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Background: Metallo-beta lactamase resistance is one of the carbapenem resistances that worsen the world nowadays. A new variant of carbapenem-resistant has only limited reports from Africa including Ethiopia. This study aimed to determine Metallo -ß- lactamase resistance Gram-negative bacteria in Hawassa University Comprehensive Specialized Hospital January–June 2023. Method: A cross-sectional study was conducted in which consecutive patients infected with Gram-negative bacteria were included in the study. A structured questionnaire was used to collect the data with oriented nurses if the patients/or caregivers gave consent to participate in the study. Clinical specimens are processed based on the standard operating procedure of the Microbiology laboratory and Clinical laboratory standard institute guidelines. Culture and sensitivity testing was used to isolate the bacteria. Gram staining and biochemical tests was used to identify the bacteria to genus and species. Kirby disc diffusion technique was used to determine the susceptibility of antibiotics. Statistical Software for Social Science (SPSS) version 21 is used for data entry and analysis. Descriptive statistics and logistic regression were used to interpret the data. The odds ratio at 95% confidence interval (CI) and p-value < 0.05 were taken as a statistically significant association. Result: Our study included 153 isolates from different specimens, 83 (54.2%) were from male patients and 70 (45.8%) were from females. Klebsiella pneumonia was the predominant 43, followed by Escherichia coli 32, Acinetobacter spp 25, Pseudomonas spp 15, Enterobacter agglomerus 9, Klebsiella ozaenae 6, Enterobacter cloacae 5, Klebsiella oxytoca 4, (Klebsiella rhinoscleromatis, Proteus mirabilis and Morganella morganii) 3, Providencia stuartii 2 and (Citrobacter spp & Proteus vulgaris) 1. The rates of multi, extensive and pan-drug resistance bacteria accounted for 128/153 (83.7%), 77 /153(50.3%), and 26/153 (17.0%), respectively. Carbapenem resistance was 21 (13.7%), of this 7.2% were Enterobacteriaceae, 5.2% were Acetinobacter spp. and 1.3% Pseudomonas spp. Metallo-beta-lactamase was 17 (11.1%), of this, Enterobacteriaceae were 9(5.9%), Acetinobacter spp. 7(4.6%), and Pseudomonas spp. 1(0.7%). There were no variables statistically significantly associated with metallo-beta-lactamase-resistant. Conclusion: Our study revealed that Metallo-beta-lactamase resistance was circulating in the study area. There was a high rate of carbapenem resistance, multi, extensive and pan-drug resistance. Therefore, a measure should be taken to alleviate the emerging threat that leaves the patients without the option of treatment. [ABSTRACT FROM AUTHOR]

The Ironwood tree (Casuarina equisetifolia) holds a significant ecological role in Guam where a decline in Ironwood trees was first documented in 2002. Studies have linked the Ironwood tree decline (IWTD) to bacteria from the Ralstonia solanacearum complex and wetwood bacteria, specifically Klebsiella oxytoca and Klebsiella variicola. Presence of termites was first found to be associated with IWTD in 2010; however, the role of termites in IWTD is still not clear. The Asian subterranean termite, Coptotermes gestroi (Wasmann) (Blattodea: Rhinotermitidae) frequently attacks Ironwood trees. As workers of this soil-dwelling species of the lower termites harbor a diverse microbial community in their bodies, we examined whether C. gestroi workers carry IWTD-associated bacteria and could, therefore, act as vectors. We described the bacterial community in C. gestroi workers using 16S rRNA gene sequencing and tested the impact of factors related to the location and health of the Ironwood tree the termites were collected from on termite bacterial diversity. Feeding assays were performed to assess if workers show preference in consumption depending on the amount of Ralstonia and wetwood bacteria in the food source. Health of Ironwood trees and level of site management impacted the bacterial composition of C. gestroi termite workers attacking the trees. Although C. gestroi workers equally consumed food sources with high and low Ralstonia and wetwood bacteria load in lab experiments, Ralstonia and other IWTD-related bacteria were not detected in considerable amounts in termite workers collected from trees. Thus, C. gestroi workers are not a vector for bacteria associated with IWTD in Guam. [ABSTRACT FROM AUTHOR]

The production of microbial proteins (MPs) has emerged as a critical focus in biotechnology, driven by the need for sustainable and scalable alternatives to traditional protein sources. This study investigates the efficacy of two experimental setups in producing MPs using the nitrogen-fixing bacterium Klebsiella oxytoca M5A1. K. oxytoca M5A1, known for its facultative anaerobic growth and capability to fix atmospheric nitrogen, offers a promising avenue for environmentally friendly protein production. This research compares the performance of a simple bubble column (BC) bioreactor, which promotes efficient mixing and cross-membrane gas transfer, with static fermentation, a traditional method lacking agitation and aeration. The study involved the parallel cultivation of K. oxytoca M5A1 in both systems, with key parameters such as microbial growth, glucose utilization, protein concentration, and metabolite profiles monitored over a 48 h period. The results indicate that the BC bioreactor consistently outperformed static fermentation regarding the growth rate, protein yield, and glucose utilization efficiency. The BC exhibited a significant increase in protein production, reaching 299.90 µg/mL at 48 h, compared to 219.44 µg/mL in static fermentation. The organic acid profile reveals both synthesis and utilization regimes of varying patterns. These findings highlight the advantages of the BC bioreactor for MP production, particularly its ability to maintain aerobic conditions that support higher growth and yield. [ABSTRACT FROM AUTHOR]

Aim: Recently, substantial studies have been accumulated to indicate the important role of gut microbiota in diabetic kidney disease (DKD). The abnormal change of bacterial‐derived products could imply specific injuries or play beneficial or harmful roles in DKD progression. In this study, we examined the presence and contribution of the Klebsiella oxytoca gene in the circulation of patients with DKD. Method: We enrolled a total of 16 healthy participants, 17 patients with DKD, 5 patients with DKD requiring haemodialysis (HD), and 7 patients with CKD without diabetes. Bacterial‐derived DNA (16S rDNA and a specific K. oxytoca gene) in the blood was detected using droplet digital PCR, then investigated the relationship with clinical characteristics. Results: We identified an increase in K. oxytoca genes in the blood of DKD patients. Interestingly, blood K. oxytoca copies and K. oxytoca/ 16S DNA ratio correlated with higher blood creatinine and BUN levels together with lower eGFR in DKD patients. K. oxytoca levels were also associated with higher neutrophil percentage, lower lymphocyte frequency, and increased neutrophil‐to‐lymphocyte ratio. Conclusion: Collectively, the presence of the K. oxytoca gene in the circulation could serve as a biomarker reflecting reduced renal function in DKD patients. [ABSTRACT FROM AUTHOR]

Purpose: The emergence of antibiotic resistance in pathogenic Enterobacteriaceae is a public health problem in tropical countries such as Burkina Faso. Antibiotic resistance could be identified using a variety of approaches. This study aimed to estimate the prevalence of pathogenic enterobacteria strains from three sources, as well as their antibiotic resistance profile to biotope and climatic season. Material and Methods: The methodological approach consisted of identifying Enterobacteriaceae from human (urine, stool), animal (eggs, milk, fish), and environmental (soil, lettuce) samples, followed by assessing their antibiotic susceptibility. Samples were collected from February to December 2023. Bacterial species were isolated and phenotypically identified (morphologically, culturally, biochemically, and antigenically) using standard methods. The prevalence of bacterial susceptibility to ten antibiotics was determined using the agar disk diffusion method. The collected data were analyzed with IBM SPSS Statistics 25 software. Results: A total of 615 Enterobacteriaceae isolates were collected, including 300, 168, and 147 samples from human, animal, and environmental sources respectively. Phenotypic characteristics allowed to partially identify 43 species, among these 29.76% belonged to Escherichia coli, 24.72% to Enterobacter cloacae, 13. 82% to Klebsiella pneumoniae, 3.41% to Enterobacter sakazakii and 2.6% to Klebsiella oxytoca. Bacterial resistance rates were: aminopenicillins (54.8%), first-generation cephalosporins (35.3%), sulfonamides (33.3%), third-generation cephalosporins (30.7%), fourth-generation cephalosporins (22.5%), fluoroquinolones (21.8%), phenicols (16.8%), and carbapenems (16.2%). The distribution of antibiotic resistance was 45.3% from human sources, 19.3% from animal sources, and 13.8% from environmental sources. Conclusion: The results indicate that resistant bacteria can come from any of the three biotopes, with human origin being the most frequent. The high prevalence of resistance to the antibiotics tested in isolated bacteria raises interest in investigating the genetic factors responsible. [ABSTRACT FROM AUTHOR]

The local application of broad-spectrum antibiotics via polymeric drug delivery systems is a promising alternative to their systemic administration in wound healing, prevention and treatment of infections associated with surgical implants. However, low and poorly controlled loading efficiency and 100% burst release are common problems for the materials with weak physical interaction between antibiotics and polymeric matrices. Here, we report a new multifunctional carboxymethyl chitosan (CMC) cryogel, which efficiently prevents bacterial adhesion to the surface, kills bacteria in the solution via controlled release of ciprofloxacin (CIP), and promotes fibroblast proliferation. The suggested approach is based on CIP loading to Zn2+-chelated CMC cryogel via the ligand exchange reaction. We have shown that, due to the strong binding of Zn2+ to CMC, the antibacterial effect and toxicity to fibroblasts of CMC-Zn-CIP cryogels were mainly determined by the content of loaded CIP, which can be precisely controlled via Zn2+ content in cryogel. CMC cryogels containing 20 mgZn/g can be loaded with CIP amounts sufficient to completely suppress the growth of hospital strain Klebsiella oxytoca with MIC of 0.125 µg/mL, while maintaining a fibroblast viability at the level of 85–90%. [ABSTRACT FROM AUTHOR]

Background: Tobacco (Nicotiana tabacum L.) is an important economic crop, and the use of plant growth-promoting bacteria (PGPB) to enhance its growth and suppress soil-borne diseases has garnered considerable research interest. However, the potential of yeast to augment the growth-promoting and disease-suppressing effects of PGPB on tobacco remains unclear. Methods: This study investigated the effects of Pichia sp. microbial fertilizer (J1), PGPB- Klebsiella oxytoca microbial fertilizer (ZS4), and their composite fertilizer (JZ) on tobacco growth indexes, soil properties, and soil microbial community through a pot experiment. Additionally, field experiments were conducted to further assess the efficacy of the composite microbial fertilizer on tobacco growth and the incidences of soil-borne diseases, including tobacco bacterial wilt (TBW) and tobacco black shank (TBS). Results and discussions: In the pot experiment, application of the microbial fertilizers significantly enhanced soil organic matter (OM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available phosphorus (AP), and available potassium (AK) levels. Compared to the control group (CK), J1, ZS4, and JZ microbial fertilizers significantly promoted tobacco growth, and the composite microbial fertilizers demonstrated superior to the individual microbial fertilizers. We found that the application of microbial fertilizer led to significant alterations in the structure and composition of the bacterial and fungal communities based on the high-throughput sequencing of 16S rRNA and internal transcribed spacer (ITS) regions. The bacterial and fungal diversity indexes showed a decreasing trend. Key microorganisms such as Sphingomonas , Kitasatospora , Nitrosospira , Mortierella , and Trichoderma were identified as influential in regulating soil physicochemical parameters to enhance tobacco growth. Functional prediction further demonstrated a significant increase in the relative abundances of certain enzymes, including Alkaline phosphatase, 1-aminocyclopropane-1-carboxylate deaminase (ACC deaminase), and Peroxidase, as well as antimicrobial substances like Tetracycline, Isoquinoline alkaloid, and Phenylpropanoids, following inoculation with the fertilizer. Besides, field experiments revealed that the JZ fertilizer significantly promoted tobacco growth and reduced the incidence of TBW and TBS, indicating its potential for further application in tobacco cultivation. [ABSTRACT FROM AUTHOR]

Background: Antimicrobial resistance (AMR) can lead to fatal consequences. AMR genes carriage by phenotypically susceptible bacteria, such as Extended-Spectrum β-Lactamases (ESBL)s in Enterobacteriaceae , have potential implications for AMR spread and therapeutic outcomes. This phenomenon should be investigated. Methods: Positive blood cultures from hospitalized patients in a Malaysian tertiary center between April 2022 and March 2023 were reviewed. A total of 137 clinical isolates of Escherichia coli (E.coli), Klebsiella pneumoniae (K.pneumoniae), and Klebsiella oxytoca were included. The antibiotic susceptibility and ESBL phenotypes were determined by disk diffusion method and the identification of genotypes by multiplex polymerase chain reaction. The clinical characteristics and outcome information were extracted by reviewing patients' medical records to evaluate the clinical significance of the ESBL genotype-positive but phenotype-negative isolates in bacteremia. Results: All 137 isolates were positive for at least one genotype (bla CTX-M, n = 71, 51.8%; bla SHV, n = 87, 63.5%; bla TEM, n = 95, 69.3%; bla OXA-1, n = 38, 27.7%). While bla CTX-M was proportionately higher in the ESBL phenotype-positive isolates than ESBL phenotype-negative isolates (33/37, 89.2% vs 38/100, 38%; p < 0.001), more than half of those harboring bla CTX-M remained susceptible to third-generation cephalosporins (3GC). The sensitivity (Sen) of bla CTX-M for ESBL phenotypes prediction was 89.19% (95% confidence interval [CI], 74.58 - 96.97%); however, specificity (Sp) was low (46.47%; 95% CI 39.75 - 53.32). The patient characteristics were similar among 98 ESBL phenotype-negative cases, except that the non- bla CTX-M carrier group had significantly more renal impairment (0/37 vs 7/61, p = 0.043) and gastrointestinal sources of bacteremia (9/37 vs 27/61, p = 0.047). No differences were observed in infection severity, in-hospital mortality, and length of stay (LOS) between the bla CTX-M and non- bla CTX-M carrier groups. Conclusion: The current study provides insight into the gene carriage in E.coli and Klebsiella species clinical isolates, including bla CTX-M genotypes in antibiotic-susceptible strains from a Malaysian hospital. The ESBL encoding genotypes such as bla CTX-M presented substantially beyond one-third of the ESBL phenotype-negative or 3GC susceptible E.coli and K.pneumoniae isolated from bloodstream infection. Although clinical outcomes were not worsened with bla CTX-M genotype-positive but ESBL phenotype-negative isolates in bacteremia, the potential implications for AMR spread deserve further investigation. [ABSTRACT FROM AUTHOR]

NK-lysins from chicken, bovine and human are used as antiviral and antibacterial agents. Gram-negative and gram-positive microorganisms, including Streptococcus pyogenes, Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa, Klebsiella oxytoca, Shigella sonnei, Klebsiella pneumoniae and Salmonella typhimurium, are susceptible to NK-lysin treatment. The presence of dominant TEM-1 gene was noted in all untreated and treated bacteria, while TOHO-1 gene was absent in all bacteria. Importantly, β-lactamase genes CTX-M-1, CTX-M-8, and CTX-M-9 genes were detected in untreated bacterial strains; however, none of these were found in any bacterial strains following treatment with NK-lysin peptides. NK-lysin peptides are also used to test for inhibition of infectivity, which ranged from 50 to 90% depending on NK-lysin species. Chicken, bo vine and human NK-lysin peptides are demonstrated herein to have antibacterial activity and antiviral activity against Rotavirus (strain SA-11). On the basis of the comparison between these peptides, potent antiviral activity of bovine NK-lysin against Rotavirus (strain SA-11) is particularly evident, inhibiting infection by up to 90%. However, growth was also significantly inhibited by chicken and human NK-lysin peptides, restricted by 80 and 50%, respectively. This study provided a novel treatment using NK-lysin peptides to inhibit expression of β-lactamase genes in β-lactam antibiotic-resistant bacterial infections. [ABSTRACT FROM AUTHOR]

Date palm (Phoenix dactylifera) considered a main income and food source for local individuals in producing countries. However, palm offshoot decline and bud rot disease was observed in some palm groves in Khuzestan province as a major date producer in Iran. Thirty‐five samples with rot and decline were collected from diseased offshoot from palm groves of six cities of Khuzestan during 2019–2021. Yellowing in outer leaves, black, brown or reddish brown spots were observed on petioles at the early stage, which gradually continues to rot. Seventy‐nine were isolated from symptomatic samples among which 38 strains caused rotting in the inoculated site and emission of a foul odour 3 weeks after inoculation on petioles and rachises of young offshoots. Based on the phenotypic characters, pathogenic strains categorised in three groups including Klebsiella oxytoca with 15, Kosakonia radicincitans with 12 and Citrobacter koseri with 11 strains. The phylogenic tree based on analysis of the concatenated partial sequences of two housekeeping genes, gyrB and infB, revealed that six representative strains clustered with the type strains of K. oxytoca and K. radicincitans. Furthermore, two strains were clustered with the type strain of C. koseri based on concatenated partial sequences of gyrB, fusA and pyrG genes. This is the first report of K. oxytoca, K. radicincitans and C. koseri, as agents of date palm offshoot decline and bud rot. The inundation of palm groves due to massive flood during 2019 and 2020 in Khuzestan province may intensify the outbreak of decline and offshoot rot disease. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the contamination levels of fresh products by ESBLs-producing Enterobacterales (ESBLs-E) or AmpC-producing Enterobacterales and characterize ESBLs genes. A total of 132 samples (67 vegetables and 65 fruits) were collected from markets in Tebessa, eastern Algeria. Among the samples, 16 third-generation cephalosporin-resistant Enterobacterales isolates were identified with a prevalence of 19.40% in vegetable samples, while there was no positive finding in fruit samples. Isolates showed resistance to most β-lactams, and all of them displayed multidrug resistance. Phenotypic tests for ESBLs detection, using double-disk synergy test and double-disk test were positive for 14 strains, including Klebsiella pneumoniae (n = 5), Klebsiella oxytoca (n = 4), Klebsiella terrigena (n = 2), Kluyvera spp. (n = 2), and Enterobacter cloacae (n = 1). Two AmpC-producing strains (Citrobacter freundii and E. cloacae) were identified through the AmpC disk test. Contamination rates of vegetables by ESBLs-E and AmpC-producing Enterobacterales were 19.40% and 2.98%, respectively. PCR results showed the presence of at least one ESBL gene in seven selected strains, with the dominance of blaCTX-M gene. Notably, K. pneumoniae strains showed the co-occurrence of two or three genes. Sequencing identified uncommon variants of ESBLs genes for the first time in Algeria, including blaCTX-M-79 (2/7), blaCTX-M-107 (2/7), blaCTX-M-117 (2/7), blaTEM-112 (1/7), blaTEM-125 (2/7), blaTEM-194 (1/7), and blaSHV-176 (3/7). [ABSTRACT FROM AUTHOR]

Klebsiella oxytoca JCM 1665 was subjected to extracellular rhodanese production using a submerged fermentation technique. The organism was further engineered for higher cyanide tolerance and rhodanese yield using ethylmethanesulfonate as a mutagen. Mutagenesis resulted in an improved mutant with high cyanide tolerance (100 mM) and rhodanese yield (26.7 ± 0.67 U/mL). This yield was 4.34-fold higher than the wild strain (6.15 ± 0.65 U/mL). At temperatures ranging from 30 to 80 °C, the first-order thermal denaturation constant (Kd) for free enzyme increases from 0.00818 to 0.0333 min−1 while the immobilized enzyme increases from 0.003 to 0.0204 min−1. The equivalent half-life reduces from 99 to 21 minutes and 231 to 35 minutes, respectively. Residual activity tests were used to assess the thermodynamic parameters for both enzyme preparations. For the free enzyme, the parameters obtained were enthalpy (29.40 to 29.06 kJ.mol−1), entropy (−194.24 to −197.50 J.mol−1K−1) and Gibbs free energy (90.20 to 98.80 kJ.mol-1). In addition, for immobilized rhodanese, we obtained enthalpy (40.40 to 40.07 kJ.mol−1), entropy (−164.21 to − 165.20 J.mol−1K−1) and Gibbs free energy (91.80 to 98.40 kJ.mol−1. Regarding its operational stability, the enzyme was able to maintain 63% of its activity after being used for five cycles. Immobilized K. oxytoca rhodanese showed a marked resistance to heat inactivation compared to free enzyme forms; making it of utmost significance in many biotechnological applications. [ABSTRACT FROM AUTHOR]

Nicosulfuron residues in soil can be harmful to the environment. In this study, Klebsiella oxytoca ES5 and Klebsiella grimontii ES8 were isolated to construct the ES58 bacterial complex. The culture medium was optimized using response surface methodology, nicosulfuron degradation by ES58 reached 97.21 % in 96 h. The optimal degradation conditions were: temperature: 25℃, pH 6, initial nicosulfuron concentration: 50 mg L−1 and inoculum volume: 2 %. The two individual strains and the bacterial complex were tested for the ability of nitrogen fixation, phosphorus solubilization, potassium decomposition and iron carrier production. The results revealed that both strains and the bacterial complex had the ability to promote the growth, with bacterial complex being more capable than the two individual bacterial strains. After 28 d of bioremediation of nicosulfuron-contaminated soil by ES58, degradation rate of nicosulfuron was 90.84 % in the unsterilized soil. Furthermore, the remediation process restored the activities of catalase, invertase, dehydrogenase and urease in the soil. The ES5-specific gene budA and ES8-specific gene ldh were detected in the soil at the 28th day. ES58 exhibited different effects on the growth indexes of nicosulfuron-sensitive crops. The study provides a novel strategy for nicosulfuron degradation effective by constructing and utilizing bacterial complex. [Display omitted] • Two strains of nicosulfuron efficient degrading bacteria were isolated and identified. • The degradation characteristics of the complex bacterium ES58 were investigated. • The growth-promoting ability of the composite bacterium ES58 was determined. • Bioremediation of nicosulfuron contaminated soil by the complex bacterium ES58 was studied. [ABSTRACT FROM AUTHOR]

Introduction: Rapid detection and identification of pathogens and antimicrobial susceptibility is essential for guiding appropriate antimicrobial therapy and reducing morbidity and mortality associated with sepsis. Objectives: The metabolic response of clinical isolates of Klebsiella oxytoca exposed to different concentrations of ciprofloxacin (the second generation of quinolones antibiotics) were studied in order to investigate underlying mechanisms associated with antimicrobial resistance (AMR). Methods: Metabolomics investigations were performed using Fourier-transform infrared (FT-IR) spectroscopy as a metabolic fingerprinting approach combined with gas chromatography-mass spectrometry (GC-MS) for metabolic profiling. Results: Our findings demonstrated that metabolic fingerprints provided by FT-IR analysis allowed for the differentiation of susceptible and resistant isolates. GC-MS analysis validated these findings, while also providing a deeper understanding of the metabolic alterations caused by exposure to ciprofloxacin. GC-MS metabolic profiling detected 176 metabolic features in the cellular extracts cultivated on BHI broth, and of these, 137 could be identified to Metabolomics Standards Initiative Level 2. Data analysis showed that 40 metabolites (30 Level 2 and 10 unknown) were differentiated between susceptible and resistant isolates. The identified metabolites belonging to central carbon metabolism; arginine and proline metabolism; alanine, aspartate and glutamate metabolism; and pyruvate metabolism. Univariate receiver operating characteristic (ROC) curve analyses revealed that six of these metabolites (glycerol-3-phosphate, O-phosphoethanolamine, asparagine dehydrate, maleimide, tyrosine, and alanine) have a crucial role in distinguishing susceptible from resistant isolates (AUC > 0.84) and contributing to antimicrobial resistance in K. oxtytoca. Conclusion: Our study provides invaluable new insights into the mechanisms underlying development of antimicrobial resistance in K. oxytoca suggests potential therapeutic targets for prevention and identification of AMR in K. oxytoca infections. [ABSTRACT FROM AUTHOR]

A novel lyophilization (freeze-drying) technique has been developed to produce the petroleum hydrocarbon (PH)–degrading bacterial strain powders for the enhancement of bioremediation of PH-polluted soils. Four different PH-degrading strains (Paenarthrobacter ureafaciens, Klebsiella oxytoca, Pseudomonas citronellolis, and Enterobacter cloacae) isolated from a PH-polluted site were used for bacterial strain powder production. The modified lyophilization buffer contained skimmed milk powder, trehalose, sucrose, and glycerin. The water content, bacterial activity, bacterial survival factor, glass transition temperature, and surface characteristics were analyzed to determine the properties of the produced bacterial strain powders. Addition of 20% skimmed milk powder as an excipient and 15% trehalose as a cryoprotectant could significantly enhance the stability and survival factor of the bacterial strains. The incorporation of 0.75% sucrose and 0.05% glycerol into the basic formula of skimmed milk powder and trehalose, respectively, could allow the bacterial strain powder to be stored at ambient temperature due to the effective environmental isolation and continuous nutrient supplement capabilities of the two agents. Up to 95% of the bacterial survival could be obtained when 24 h of prefreezing at −80°C was applied as the first stage of the modified lyophilization process followed by the second stage of freeze-drying for 24 h. With this process, the depreciation rate was less than 1% after storing the powder for 6-month at 25°C. The glass transition temperature of the strain powder fell within the range of 10°C to 25°C, indicating that the optimized formulation for bacterial strain powder production could facilitate the strain storage at room temperature and produce diverse powder variants. Through the application of novel lyophilization process, more stable bacterial strain powder could be produced with a higher survival factor and a longer storage period. Up to 83% of total PH removal could be obtained in microcosms with the application of strain bacterial powders. [ABSTRACT FROM AUTHOR]

Abstract Background Whey, which has high biochemical oxygen demand and chemical oxygen demand, is mass-produced as a major by-product of the dairying industry. Microbial fermentation using whey as the carbon source may convert this potential pollutant into value-added products. This study investigated the potential of using whey powder to produce α-ketoisovalerate, an important platform chemical. Results Klebsiella oxytoca VKO-9, an efficient L-valine producing strain belonging to Risk Group 1 organism, was selected for the production of α-ketoisovalerate. The leucine dehydrogenase and branched-chain α-keto acid dehydrogenase, which catalyzed the reductive amination and oxidative decarboxylation of α-ketoisovalerate, respectively, were inactivated to enhance the accumulation of α-ketoisovalerate. The production of α-ketoisovalerate was also improved through overexpressing α-acetolactate synthase responsible for pyruvate polymerization and mutant acetohydroxyacid isomeroreductase related to α-acetolactate reduction. The obtained strain K. oxytoca KIV-7 produced 37.3 g/L of α-ketoisovalerate from lactose, the major utilizable carbohydrate in whey. In addition, K. oxytoca KIV-7 also produced α-ketoisovalerate from whey powder with a concentration of 40.7 g/L and a yield of 0.418 g/g. Conclusion The process introduced in this study enabled efficient α-ketoisovalerate production from low-cost substrate whey powder. Since the key genes for α-ketoisovalerate generation were integrated in genome of K. oxytoca KIV-7 and constitutively expressed, this strain is promising in stable α-ketoisovalerate fermentation and can be used as a chassis strain for α-ketoisovalerate derivatives production.

Objectives: This study describes the detection and tracking of emergency neurosurgical cross-transmission infections with carbapenem-resistant Klebsiella oxytoca (CRKO). Methods: We conducted an epidemiological investigation and a rapid screening of 66 surveillance samples using the chromogenic selective medium. Two CRKO isolates from infected patients and three from the preoperative shaving razors had similar resistance profiles identified by the clinical laboratory. Results: The whole genome sequencing (WGS) results identified all isolates as Klebsiella michiganensis (a species in the K. oxytoca complex) with sequence type 29 (ST29) and carrying resistance genes blaKPC-2 and blaOXY-5, as well as IncF plasmids. The pairwise average nucleotide identity values of 5 isolates ranged from 99.993% to 99.999%. Moreover, these isolates displayed a maximum genetic difference of 3 among 5,229 targets in the core genome multilocus sequence typing scheme, and the razors were confirmed as the contamination source. After the implementation of controls and standardized shaving procedures, no new CRKO infections occurred. Conclusion: Contaminated razors can be sources of neurosurgical site infections with CRKO, and standard shaving procedures need to be established. Chromogenic selective medium can help rapidly identify targeted pathogens, and WGS technologies are effective mean in tracking the transmission source in an epidemic or outbreak investigation. Our findings increase the understanding of microbial transmission in surgery to improve patient care quality. [ABSTRACT FROM AUTHOR]

Background: Antibiotic resistance of Enterobacterales poses a major challenge in the treatment of urinary tract infections (UTIs). In low- and middle-income countries (LMICs), standard microbiological (i.e. urine culture and simple disk diffusion test) methods are considered the "gold standard" for bacterial identification and drug susceptibility testing, while PCR and DNA sequencing are less commonly used. In this study, we aimed to re-identifying Enterobacterales as the primary bacterial agents responsible for urinary tract infections (UTIs) by comparing the sensitivity and specificity of traditional microbiological methods with advanced molecular techniques for the detection of uropathogens in indigenous women from Otavalo, Ecuador. Methods: A facility-based cross-sectional study was conducted from October 2021 to February 2022 among Kichwa-Otavalo women. Pathogens from urine samples were identified using culture and biochemical typing. Morphological identification was doble-checked through PCR and DNA sequencing of 16S, recA, and rpoB molecular barcodes. The isolates were subjected to antimicrobial susceptibility-testing using disk diffusion test. Results: This study highlighted a 32% misidentification rate between biochemical and molecular identification. Using traditional methods, E. coli was 26.19% underrepresented meanwhile Klebsiella oxytoca was overrepresented by 92.86%. Furthermore, the genera Pseudomonas, Proteus, and Serratia were confirmed to be E. coli and Klebsiella spp. by molecular method, and one Klebsiella spp. was reidentified as Enterobacter spp. The susceptibility profile showed that 59% of the isolates were multidrug resistant strains and 31% produced extended spectrum beta-lactamases (ESBLs). Co-trimoxazole was the least effective antibiotic with 61% of the isolates resistant. Compared to previous reports, resistance to nitrofurantoin and fosfomycin showed an increase in resistance by 25% and 15%, respectively. Conclusions: Community-acquired UTIs in indigenous women in Otavalo were primarily caused by E. coli and Klebsiella spp. Molecular identification (16S/rpoB/recA) revealed a high rate of misidentification by standard biochemical and microbiological techniques, which could lead to incorrect antibiotic prescriptions. UTI isolates in this population displayed higher levels of resistance to commonly used antibiotics compared with non-indigenous groups. Accurate identification of pathogens causing UTIs and their antibiotic susceptibility in local populations is important for local antibiotic prescribing guidelines. [ABSTRACT FROM AUTHOR]

Individuals with pancreatic-related health conditions usually show lower diversity and different composition of bacterial and viral species between the gut and oral microbiomes compared to healthy individuals. We performed a thorough microbiome analysis, using deep shotgun sequencing of stool and saliva samples obtained from patients with chronic pancreatitis (CP), pancreatic ductal adenocarcinoma (PDAC), and healthy controls (HCs).We observed similar microbiota composition at the species level in both the gut and oral samples in PDAC patients compared to HCs, among which the most distinctive finding was that the abundance of oral-originated Fusobacterium nucleatum species did not differ between the oral and the gut samples. Moreover, comparing PDAC patients with HCs, Klebsiella oxytoca was significantly more abundant in the stool samples of PDAC patients, while Streptococcus spp. showed higher abundance in both the oral and stool samples of PDAC patients. Finally, the most important finding was the distinctive gut phage–bacterial interactome pattern among PDAC patients. CrAssphages, particularly Blohavirus, showed mutual exclusion with K. oxytoca species, while Burzaovirus showed co-occurrence with Enterobacteriaceae spp., which have been shown to be capable of inducing DNA damage in human pancreatic cells ex vivo. The interactome findings warrant further mechanistic studies, as our findings may provide new insights into developing microbiota-based diagnostic and therapeutic methods for pancreatic diseases. [ABSTRACT FROM AUTHOR]

Virulent Klebsiella oxytoca strains are associated with gut and lung pathologies, yet our understanding of the molecular signals governing pathogenesis remains limited. Here, we characterized a family of K. oxytoca pyrazine and pyrazinone autoinducers and explored their roles in microbial and host signaling. We identified the human mucin capping sugar Neu5Ac as a selective elicitor of leupeptin, a protease inhibitor prevalent in clinical lung isolates of K. oxytoca, and leupeptin-derived pyrazinone biosynthesis. Additionally, we uncovered a separate pyrazine pathway, regulated by general carbohydrate metabolism, derived from a broadly conserved PLP-dependent enzyme. While both pyrazine and pyrazinone signaling induce iron acquisition responses, including enterobactin biosynthesis, pyrazinone signaling enhances yersiniabactin virulence factor production and selectively activates the proinflammatory human histamine receptor H4 (HRH4). Our findings suggest that the availability of specific carbohydrates delineates distinct autoinducer pathways in K. oxytoca that may have differential effects on bacterial virulence and host immune responses. Differential carbohydrate metabolism elicits distinct pyrazine and pyrazinone autoinducer signalling pathways in Klebsiella oxytoca, which impact bacterial virulence programs. [ABSTRACT FROM AUTHOR]

Background: Whey, which has high biochemical oxygen demand and chemical oxygen demand, is mass-produced as a major by-product of the dairying industry. Microbial fermentation using whey as the carbon source may convert this potential pollutant into value-added products. This study investigated the potential of using whey powder to produce α-ketoisovalerate, an important platform chemical. Results: Klebsiella oxytoca VKO-9, an efficient L-valine producing strain belonging to Risk Group 1 organism, was selected for the production of α-ketoisovalerate. The leucine dehydrogenase and branched-chain α-keto acid dehydrogenase, which catalyzed the reductive amination and oxidative decarboxylation of α-ketoisovalerate, respectively, were inactivated to enhance the accumulation of α-ketoisovalerate. The production of α-ketoisovalerate was also improved through overexpressing α-acetolactate synthase responsible for pyruvate polymerization and mutant acetohydroxyacid isomeroreductase related to α-acetolactate reduction. The obtained strain K. oxytoca KIV-7 produced 37.3 g/L of α-ketoisovalerate from lactose, the major utilizable carbohydrate in whey. In addition, K. oxytoca KIV-7 also produced α-ketoisovalerate from whey powder with a concentration of 40.7 g/L and a yield of 0.418 g/g. Conclusion: The process introduced in this study enabled efficient α-ketoisovalerate production from low-cost substrate whey powder. Since the key genes for α-ketoisovalerate generation were integrated in genome of K. oxytoca KIV-7 and constitutively expressed, this strain is promising in stable α-ketoisovalerate fermentation and can be used as a chassis strain for α-ketoisovalerate derivatives production. [ABSTRACT FROM AUTHOR]

Aims Klebsiella michiganensis is a medically important bacterium that has been subject to relatively little attention in the literature. Interrogation of sequence data from K. michiganensis strains in our collection has revealed the presence of multiple large plasmids encoding type II toxin–antitoxin (TA) systems. Such TA systems are responsible for mediating a range of phenotypes, including plasmid stability ('addiction') and antibiotic persistence. In this work, we characterize the hipBA TA locus found within the Klebsiella oxytoca species complex (KoSC). Methods and results The HipBA TA system is encoded on a plasmid carried by K. michiganensis PS_Koxy4, isolated from an infection outbreak. Employing viability and plasmid stability assays, we demonstrate that PS_Koxy4 HipA is a potent antibacterial toxin and that HipBA is a functional TA module contributing substantially to plasmid maintenance. Further, we provide in silico data comparing HipBA modules across the entire KoSC. Conclusions We provide the first evidence of the role of a plasmid-encoded HipBA system in stability of mobile genetic elements and analyse the presence of HipBA across the KoSC. These results expand our knowledge of both a common enterobacterial TA system and a highly medically relevant group of bacteria. [ABSTRACT FROM AUTHOR]

Simple Summary: The black soldier fly (Hermetia illucens L.) is a saprophagous insect belonging to the Stratiomyidae family that can degrade organic waste and convert it into high-quality insect protein and lipid. Corn straw is a kind of prevalent agricultural waste. In this study, black soldier fly larvae were reared with corn straw to obtain larval biomass and consume corn straw. The results showed that most of the black soldier fly larvae could survive and gain weight when fed with corn straw. Gut microorganisms could respond to the substrates, and four cellulase-producing strains isolated from the gut were beneficial to digesting corn straw. Corn straw is considered a renewable biomass energy source, and its unreasonable disposal leads to resource waste and environmental pollution. Black soldier fly (Hermetia illucens L.) larvae (BSFL) facilitate the bioconversion of various types of organic wastes. In this study, we found that 88% of BSFL survived, and 37.4% of corn straw was digested after 14 days of feeding with corn straw. Contrary to expectations, the pretreatment of corn straw with alkaline hydrogen peroxide did not promote its digestion but rather reduced the growth and survival rates of BSFL. Acinetobacter, Dysgonomonas, and unclassified Enterobacteriaceae were the abundant genera in the BSFL gut fed with corn straw. Compared with the standard diet, the relative abundances of carbohydrate metabolism genes, such as the gene abundances of β-glucosidase and α-glucosidase, were higher with corn straw as the substrate. These results suggested that the gut microbial community could regulate suitable and functional microorganisms in response to the substrates. Furthermore, four cellulase-producing strains, namely Klebsiella pneumoniae, Proteus mirabilis, Klebsiella oxytoca, and Providencia rettgeri, were isolated from the guts of corn straw BSFL. These four strains helped increase the conversion rates of corn straw, the weights of BSFL, and survival rates. In summary, we reared BSFL with corn straw and discovered the functions of gut microorganisms in adapting to the substrates. We also isolated four cellulase-producing strains from the BSFL guts and declared the benefits of BSFL digesting corn straw. [ABSTRACT FROM AUTHOR]

Klebsiella oxytoca is a causative agent of various community-acquired and nosocomial infections, including urinary tract infections, nosocomial pneumonia, antibiotic-associated diarrhea, etc. However, the virulence factors of the species are still incompletely understood. The adhesive potential of the urological isolate K. oxytoca NK-1 was characterized using several substrates. The strain was found to efficiently adhere to epithelial cell lines, glycosylated and nonglycosylated proteins, and polystyrene and to induce yeast cell agglutination, indicating the presence of type 1 and type 3 fimbriae, which are organelles that facilitate adhesion of enterobacteria to a wide range of substrates. Both type 1 and type 3 fimbrial operons were identified in the strain genome, the latter occurring in two copies. Mutants with inactivated fimbrial genes were constructed. Inactivation of type 1 fimbrial genes did not affect bacterial adhesion. Inactivation of type 3 fimbrial genes increased adhesion of K. oxytoca NK-1 to lung epithelial cells (line H1299), and mannose was shown to serve as an additional inducer of higher adhesion. Adhesion of the mutant to other substrates was not affected. The findings suggested a multifactorial nature for the K. oxytoca adhesive apparatus and the possibility of compensatory expression or overexpression of genes for alternative adhesins in the absence of type 1 and/or 3 fimbriae. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The objective of this study was to describe the prevalence of antimicrobial resistance of Escherichia coli , Klebsiella oxytoca , Klebsiellapneumoniae , and Serratiamarcescens from quarter milk samples submitted to the udder health laboratory of the Bavarian Animal Health Services (TGD) in Southern Germany between 2014 and 2022. All samples were tested with the California Mastitis Test and analyzed with a standard microbroth dilution to determine the MIC. The antimicrobials tested were amoxicillin/clavulanate, cefazoline, kanamycin/cefalexin, cefoperazone, cefquinome, and marbofloxacin. Breakpoints were chosen in accordance with the Clinical and Laboratory Standards Institute (CLSI). Over the study period, E. coli , K. oxytoca , and K. pneumoniae showed only few resistances to all antimicrobials tested. For those pathogens MIC 50 and MIC 90 were below breakpoint for all antimicrobials except cefoperazone over the 9 years. A decrease in MIC could be seen for E. coli and K. oxytoca for all of the antimicrobials. While the MIC for K. pneumoniae stayed more stagnant, the prevalence of resistance still decreased overall. Serratiamarcescens isolates were proven intrinsically resistant to amoxicillin/clavulanate and cefazolin, and while in vitro resistances were low for all other antimicrobials tested, S. marcescens tended toward higher MIC for most of the antimicrobials over the years. Over time, there was also an overall increase in the number of isolates for all 4 pathogens per year. Starting 2018 there was a steep increase in the number of isolates particularly from clinical cases. This jump in numbers coincided with a change of the regulation for veterinary drug prescriptions in Germany in 2018 that required, among other things, antimicrobial resistance testing before a change of antibiotics in the course of treatment and the use of critically important antimicrobials. Overall, although the pathogens increased in numbers, the prevalence of their antimicrobial resistance remained low. [ABSTRACT FROM AUTHOR]

There are significant reasons for nitrate contamination in groundwater (Delhi, India): sewage, runoff from landfill sites, nitrogenous chemical fertilisers, and pesticides from agricultural lands. The highest recorded concentration of nitrate in Delhi's groundwater is reported to be 1500 mg/l. Consumption of high nitrate through water may pose serious health problems in humans, especially children (below five years). The study's primary objective was to isolate and identify nitrate-remediating microbes from the nitratecontaminated site Okhla Barrage, located on the Yamuna River in Delhi, India. A total of 11 different strains were isolated from this site. Among these four strains exhibited 40%-50% remediation efficiency at a nitrate concentration of 1000 mg/l. Molecular characterisation revealed that these four strains, Enterobacter aerogenes, E. coli K12, Klebsiella oxytoca and Lelliottia amnigena, belong to the Enterobacteriaceae family. This study assessed the nitrate remediation potential of isolated microbes in groundwater with 1000 and 1500 mg/l nitrate concentrations. By using a 2% inoculum, the microbes were incubated anaerobically at room temperature for ten days. Nitrate concentrations were monitored every 48 hours. Lelliottia, E. coli, and Enterobacter reduced nitrate (1500 mg/l) by approximately 42%, 24%, and 29%, respectively, while K. oxytoca showed minimal reduction. L. amnigena exhibited superior nitrate removal efficiency compared to other strains. According to the reported data, these strains are known to reduce nitrate concentrations of 620 mg/l. However, our findings demonstrate a remarkable nitrate remediation capacity of 1500 mg/l, showcasing a novel contribution to this study. Further detailed analysis for condition optimisation and association of microbe-microbe could be more helpful. [ABSTRACT FROM AUTHOR]

Microbial mimicry, the process in which a microbial antigen elicits an immune response and breaks tolerance to a structurally related selfantigen, has long been proposed as a mechanism in autoimmunity. In this issue of the JCI, Dolton et al. extend this paradigm by demonstrating that a naturally processed peptide from Klebsiella oxytoca acts as a superagonist for autoreactive T cells in type 1 diabetes (T1D). Reframing microbial mimics as superagonists that are thousands of times better at binding disease-associated autoreactive T cell receptors than self-peptides serves to narrow the search space for relevant sequences in the vast microbial proteome. Moreover, the identified superagonists have implications for the intervention and personalized monitoring of T1D that may carry over to other autoimmune diseases with microbial mimicry. [ABSTRACT FROM AUTHOR]

Colombia is the ninth largest producer of dragon fruit in the world and the department of Boyacá is the largest with 440 hectares planted. Bacterial phytopathogens can cause pitahaya fruit losses and low yields by producing stem soft rot. This research aimed to study and identified possible agents of bacterial diseases of pitahaya in Boyacá, Colombia. Thirteen farms in the region were selected to take 20 samples by means of a targeted and random sampling of stem and fruit tissues with soft rot symptoms in the early stages of the disease. A process of microbiological isolation, biochemical and molecular taxonomic identification of the isolated bacteria. The 16s rRNA gene sequences of the V2-V5 region were edited by removing the primers, assembling and obtaining the consensus sequence of the primers 1100R-337F and 800R -518F. The phylogenetic analysis was performed by BLAST at NCBI, using the "Classifier" and "SeqMatch" tools from the RDP website, and phylogenetic trees were created by multiple alignment using the MUSCLE algorithm and the Tamura Nei distance method was performed. Signs like blisters and mucilaginous fluids, symptoms like yellow and brown chlorotic spots, soft rot, and liquefaction were identified, and possible vectors like flies and ants were report. Twenty-five bacterial morphotypes were identified classifieds in 4 phyla, 9 families and 13 genera. The analysis of the 16S rRNA gene sequences of the bacterial strains showed a 98 to 100% identity with Enterobacter cloacae, Pectobacterium carotovora and Paenibacillus glucanolyticus, reported in other studies as causing the soft rot of the pitahaya stem and fruit. New species were reported as possible pathogenic bacteria of pitahaya: Pantoea cypripedii, Kluyvera intermedia and Klebsiella oxytoca. Infectivity assays did not have positive results. The microbiota identified in the stages of the necrotrophic phase or final stage of soft rot of the stem belong to the genera Achromobacter, Sphingobacterium, Pseudomonas, Klebsiella, Paenibacillus, Bacillus, Stenotrophomonas and Microbacterium. In the fly Leptoglossus zonatus associated with the crop were identified Pseudomonas fulva and Lysinibacillus fusiformis were identified. This is also the first official report of a complex of possible phytopathogen bacteria of the order Enterobacterales (Enterobacteriacea, Erwiniaceae and Pectobacteriaceae family) in symptoms by bacterial disease on pitahaya Colombian crops. Identification of the bacteria in a pathogenic system can guide chemical and biological control practices in order to increase the productive and export potential of exotic and orphan crops from small local farmings. [ABSTRACT FROM AUTHOR]

In the context of global efforts to combat antimicrobial resistance (AMR), the importance of comprehensive AMR data is more crucial than ever. AMR surveillance networks, such as the European Antimicrobial Resistance Surveillance Network (EARS-Net) and the Central Asian and European Surveillance of Antimicrobial Resistance (CAESAR), support member states in obtaining high-quality AMR data. Nevertheless, data gaps persist in some countries, including those in the Western Balkans (WBs), a region with high AMR rates. This review analyzed existing research on carbapenem-resistant Enterobacterales (CRE) to better understand the AMR landscape in the WB countries. The most prevalent CRE was Klebsiella pneumoniae, followed by Escherichia coli, Enterobacter cloacae, and Proteus mirabilis, with sporadic cases of Morganella morganii, Providencia spp., Klebsiella oxytoca, and Citrobacter sedlakii. Carbapenemase production was identified as the most common mechanism of carbapenem resistance, but other resistance mechanisms were not investigated. An increasing trend in carbapenem resistance has been observed over the last decade, alongside a shift in carbapenemase epidemiology from the NDM type in 2013–2014 to the OXA-48 type in recent years. Few studies have applied whole-genome sequencing for CRE analysis, which has demonstrated the spread of resistance determinants across different niches and over time, emphasizing the importance of molecular-based research. The overall low number of studies in the WB countries can be attributed to limited resources, highlighting the need for enhanced support in education, training, technology, and equipment to improve data collection and evaluation. [ABSTRACT FROM AUTHOR]

The fruit and vegetable industry in post-harvest processing plants is characterized by a substantial consumption of water resources. Wash waters may serve as an environment for the periodic or permanent habitation of microorganisms, particularly if biofilm forms on the inner walls of tanks and flushing channels. Despite the implementation of integrated food safety monitoring systems in numerous countries, foodborne pathogens remain a global public health and food safety concern, particularly for minimally processed food products such as vegetables and fruits. This necessitates the importance of studies that will explore wash water quality to safeguard minimally processed food against foodborne pathogen contamination. Therefore, the current study aimed to isolate and identify bacteria contaminating the wash waters of four fresh-cut processing plants (Poland) and to evaluate the phenotypic antibiotic resistance profiles in selected species. Bacteria were isolated using membrane filtration and identified through mass spectrometry, followed by antibiotic susceptibility testing according to EUCAST guidelines. The results revealed that the level of contamination with total aerobic bacteria in the water ranged from 1.30 × 106 cfu/mL to 2.54 × 108 cfu/mL. Among the isolates, opportunistic pathogens including Enterococcus faecalis, Pseudomonas aeruginosa, Klebsiella oxytoca, Klebsiella pneumoniae, Serratia marcescens, and Proteus vulgaris strains were identified. An especially noteworthy result was the identification of cefepime-resistant K. oxytoca isolates. These findings highlight the importance of monitoring the microbial microflora in minimally processed foods and the need for appropriate sanitary control procedures to minimize the risk of pathogen contamination, ensuring that products remain safe and of high quality throughout the supply chain. [ABSTRACT FROM AUTHOR]

Bovine mastitis is a worldwide disease affecting dairy cattle and causes major economic losses in the dairy industry. Recently, the emergence of microbial resistance to the current antibiotics complicates the treatment protocol which necessitates antibiotic stewardship and further research to find new active compounds. Recently, phytobiotics have gained interest in being used as an alternative to antibiotics in the poultry industry as an antibiotic stewardship intervention. This study evaluated the in vitro antibacterial activity of 16 flavonoids against bovine mastitis pathogens. Two flavones: 2-(4-methoxyphenyl)chromen-4-one (1) and 2-(3-hydroxyphenyl)chromen-4-one (4) showed inhibition of the growth of Klebsiella oxytoca with MIC values range (25–50 µg mL− 1) followed by a structure-activity relationship (SAR) study indicating that the presence of a hydroxyl group at C-3' or methoxy at C-4' increases the activity against Klebsiella oxytoca while the presence of hydroxyl group at C-7 decreases the activity. Furthermore, a structure-based drug development approach was applied using several in silico tools to understand the interactions of active flavones at the active site of the DNA gyrase protein. Compound (4) showed a higher docking score than quercetin (standard) which is known to have antibacterial activity by inhibiting the DNA gyrase. In addition, the structure-based pharmacophores of compound (4) and quercetin showed similar pharmacophoric features and interactions with DNA gyrase. Based on our findings, compounds (1) and (4) are promising for further study as potential anti-microbial phytochemicals that can have a role in controlling bovine mastitis as well as to investigate their mechanism of action further. [ABSTRACT FROM AUTHOR]

Introduction: Klebsiella pneumoniae (K. pneumoniae) is the most common pathogen causing hospital respiratory tract infection and epidemic. Gold standard procedures of microscopic examination and biochemical identification are widely used in clinical diagnosis with disadvantages of low sensitivity, time-consuming and sophisticated equipment requiring. An efficient, nucleic acid amplification-based sensitive and specific on-site identification of K. pneumoniae in clinical is necessary to facilitate clinical medication and disease control. Methods: We developed a closed dumbbell mediated isothermal amplification (CDA) assay for the rapid and sensitive detection of conserved rcsA gene in K. pneumoniae by real-time fluorescence monitoring and end-point colorimetric judgement. We designed and selected a pair of inner primers of CDA to detect K. pneumoniae. Then outer and loop primers were designed and verified to accelerate CDA reaction to achieve more efficient detection of K. pneumoniae. Results: The results showed the detection limit of CDA assay was 1.2x10-5 ng/μL (approximately 1 copy of the target gene) within 60 min, which was 100-fold more sensitive than real-time quantitative PCR (qPCR). Several pathogen genomic DNAs (Staphylococcus aureus, Shigella sonnei, Vibrio parahaemolyticus, Escherichia coli, Candida glabrata, Candida tropicalis, Candida parapsilosis, Candida albicans, Streptococcus agalactiae, Rickettsia, Listeria monocytogenes, Pseudomonas aeruginosa, Klebsiella oxytoca, and Klebsiella aerogenes) were used to evaluate the sensitivity and specificity of the established K. pneumoniae CDA assay. Total 224 batches of samples from other strains tested were negative and 296 batches of extracted K. pneumoniae DNA samples were positive by the developed CDA amplification approach, revealing high specificity and specificity of the diagnostic assay. In addition, the results of real-time fluorescence amplification of the K. pneumoniae CDA were in consistent with those of end-point colorimetric results. Discussion: The established real-time fluorescence and visual CDA assays of K. pneumoniae with merits of rapid, sensitive and specificity could be helpful for on-site diagnosis and clinical screening in rural areas. [ABSTRACT FROM AUTHOR]

Background: Food-associated antibiotic-resistant bacteria can cause infections that may critically impact human health. The objectives of this study were to determine the microbial contamination level of green leafy vegetables and their antibiotic resistance pattern. Methods: Sixty-three samples of leafy vegetables were collected from Dammam Central Fruit and Vegetables Market from January to June 2023. The vegetables included lettuce (Lactuca sativa), parsley (Petroselinum crispum), and watercress (Nasturtium officinale). Samples were tested by standard microbiological techniques for identification and antibiotic susceptibility testing. Result: Eight types of bacteria belonging to six different genera were detected. Enterobacteriaceae family was represented by four genera: Klebsiella, Proteus, Morganella, and Enterobacter. The other two genera were Pseudomonas and Aeromonas. Enterobacter cloacae was the most abundant organism, followed by Pseudomonas putida and Aeromonas sobria. On the other hand, Morganella morganii, Aeromonas hydrophila, and Proteus mirabilis were the least abundant. The three vegetable types had different levels of bacterial contamination. All isolated organisms were sensitive to penicillin, cephalosporin, aminoglycoside, and fluoroquinolone. However, Klebsiella oxytoca, M. morganii, and K. pneumonia showed resistance to ampicillin. A. hydrophila, Morganella morganii, and E. cloacae showed resistance to amoxicillin. M. morganii and E. cloacae were found to be resistant to cefalotin. Moreover, A. hydrophila, M. morganii, and E. cloacae were resistant to cefoxitin. Again, A. hydrophila was found to be resistant to imipenem. Only M. morganii was resistant to Ciprofloxacin. Two isolates, P. mirabilis and M. morganii were resistant to tigecycline. Another two, M. morganii and P. mirabilis were resistant to Nitrofurantoin. Only M. morganii was found to be resistant to trimethoprim. Conclusion: This study aligns with the broad consensus in the literature about the significance of bacterial contamination in vegetables and the public health implications. The unique focus on antibiotic resistance patterns adds an essential dimension to the existing body of knowledge. [ABSTRACT FROM AUTHOR]

Klebsiella michiganensis is an emerging pathogen. In this context, we characterised a strain fxq isolated from a cerebrospinal fluid specimen of a patient with tentorial meningioma, and the K. michiganensis isolate produced carbapenemases of KPC and NDM types. Methods: The Phoenix 100 Automated Microbiology System, MALDI-TOF and whole-genome sequencing were used to identify the species. Anti-microbial susceptibility testing was also conducted with the Phoenix 100. The plasmid locations of the blaKPC-2 and blaNDM-1 genes were determined by S1-nuclease pulsed-field gel electrophoresis and Southern blot. The transfer capacity of plasmids carrying blaKPC-2 and blaNDM-1 was investigated by conjugation experiments, and the resistance plasmid stability was evaluated by culture and subculture. K. michiganensis subtypes were identified by multi-locus sequence typing. We performed whole-genome sequencing to confirm species, characterise plasmids and analyse core genes. Results: fxq was originally identified as Klebsiella oxytoca and showed resistance to imipenem and meropenem, but whole-genome sequencing identified it to be K. michiganensis. The strain fxq belonged to the novel sequence type 202 (ST202) and carried the blaKPC-2 and blaNDM-1 genes located on the pB_KPC InFIA and pE_NDM IncU plasmids, respectively. The blaKPC-2-carrying plasmid was successfully transferred to Escherichia coli EC600 by conjugation, whereas the blaNDM-1 gene on the pE_NDM plasmid was not. The pB_KPC and pE_NDM plasmids demonstrated high stability. Conclusion: This work is the first report on a carbapenem-resistant clinical isolate K. michiganensis ST202 harbouring the blaKPC-2 and blaNDM-1 genes encoded by the IncFIA and IncU plasmids, respectively. [ABSTRACT FROM AUTHOR]

Background: Patient safety is seriously threatened by bacterial infections that spread through blood transfusions (TTBI). It has been noticed that a number of infectious viral, bacterial, and parasitic pathogens are involved as barriers to the patient's blood safety. This study aimed to determine the antibiotic resistance pattern of bacteria in the donors’ blood attending Federal Medical Centre, Birnin Kebbi, Kebbi State, Nigeria. Methods: The study adopted a cross-sectional research design. A structured questionnaire was administered to 120 blood donors to obtain bio-demographic information and their blood was collected accordingly. The blood samples were processed using standard bacteriological analysis. The isolated bacteria was confirmed using standard biochemical tests. The identified bacteria were subjected to antibiotic testing using the Kirby-Bauer disc diffusion method. Results: Twenty-four 24(20.0%) blood samples were found contaminated with bacteria. The main bacteria isolates were Gram-negative organisms namely- Klebsiella oxytoca (20.8%), Citrobacter diversus (16.7%), Enterobacter aerogene (16.7%), Shigella sonnei (12.5%), Shigella dysentrae (4.2%), Morganella morganii (4.2%), Escherichia coli (4.2%) with only Staphylococcus aureus (20.8%) as Gram-positive bacteria. The prevalence rate of TTBIs was high within the age group 36-49 years 12(50.0%). Morganella morganii was (100%) resistance to all the antibiotics used in this study. Conclusions: the study revealed that, donors’ blood was contaminated with Gram-negative bacteria which are capable of causing sepsis and which may result in death. Therefore, it is recommended that screening for bacterial infections should be done routinely because of the threat it posed as seen in Federal Medical Centre, Birnin Kebbi, Kebbi state, Nigeria. [ABSTRACT FROM AUTHOR]

In August 2021, two juvenile male Antarctic fur seals (Arctocephalus gazella) stranded in the southeastern Brazilian coast and were referred to rehabilitation centers. The animals presented increased body temperature, prostration, respiratory distress and despite treatment died. A necropsy following a standardized protocol was performed, and formalin-fixed tissues were processed for microscopic examination. Samples were screened for morbillivirus, herpesvirus, and Brucella spp. by molecular analyses (PCR, RT-PCR). Bacteriological culture was performed in samples collected from the lungs, trachea, and lymph nodes of both cases. The main histopathologic findings were of infectious nature, including multifocal necrotizing and fibrinous mixed interstitial pneumonia, bronchiolitis, and bronchitis, with intralesional myriad bacteria associated with vascular fibrinoid necrosis. Pseudomonas aeruginosa was isolated from tracheal and lung swabs of Case 1, and Klebsiella oxytoca was found in nostril swabs, tracheobronchial lymph nodes, and lung of Case 2. Gammaherpesvirus infection was detected in both cases, and the sequences retrieved were classified into the genus Percavirus. All tested samples were PCR-negative for Brucella spp. and morbillivirus. We hypothesize that the deficient immunological status in association with starvation predisposed the reactivation of herpesvirus and secondary bacterial co-infections. To the authors' knowledge, this is the first molecular detection of herpesvirus in an Antarctic pinniped. These findings reinforce that Otariid gammaherpesvirus circulating in the Southern Hemisphere are likely endemic in the Arctocephalus genus. This report contributes to the current knowledge of health aspects affecting wild pinnipeds, especially in the poorly studied Antarctic species. [ABSTRACT FROM AUTHOR]

To provide a scientific basis for controlling mulberry bacterial blight in Bazhong, Sichuan, China (BSC), this study aimed to isolate and purify pathogenic bacteria from diseased branches of mulberry trees in the region and to clarify their taxonomic status using morphological observation, physiological and biochemical detection, molecular-level identification, and the construction of a phylogenetic tree. A total of 218 bacterial strains were isolated from samples of diseased mulberry branches. Of these, 7 strains were identified as pathogenic bacteria based on pathogenicity tests conducted in accordance with Koch's postulates. Preliminary findings from the analysis of the 16S rRNA sequence indicated that the 7 pathogenic bacteria are members of Klebsiella spp. Morphological observation revealed that the pathogenic bacteria were oval-shaped and had capsules but no spores. They could secrete pectinase, cellulase, and protease and were able to utilize D-glucose, D-mannose, D-maltose, and D-Cellobiose. The 7 strains of pathogenic bacteria exhibited the highest homology with Klebsiella oxytoca. This study identifies Klebsiella oxytoca as the causative agent of mulberry bacterial blight in BSC, laying the foundation for the prevention and control of this pathogen and further investigation into its pathogenic mechanism. Supplementary Material Supplementary Material File [ABSTRACT FROM AUTHOR]

Background: In this study, Escherichia coli, Klebsiella oxytoca, and Citrobacter amalonaticus carrying blaNDM-5 were isolated from a single patient. Methods: The antibiotic susceptibility of the isolates was evaluated by using E-test and agar dilution methods, and blaNDM-5 was identified in genomic and plasmid DNA by using polymerase chain reaction and sequencing. Whole genome sequencing and de novo assembly were used for species characterization, resistance gene identification, and plasmid analysis. Results: All three species had identical plasmids, which were similar to pEC463-NDM5, a plasmid harboring blaNDM-5. Transconjugation experiments confirmed the horizontal gene transfer of blaNDM-5, highlighting the need for a close monitoring of Enterobacteriaceae species harboring this gene. Conclusions: This study conclusively demonstrates the propensity for horizontal gene transfer of blaNDM-5 among Enterobacteriaceae species, underlining the importance of vigilant monitoring to combat antibiotic resistance. [ABSTRACT FROM AUTHOR]

Background and Aims: Klebsiella oxytoca (K. oxytoca) is the second bacterial cause of nosocomial infections in the general population after K. pneumoniae. This study surveyed the frequency of cytotoxin‐producing strains of K. oxytoca and their antibiotic susceptibility profile in a cohort of children admitted to a referral hospital with different malignancies. Methods: The Stool samples of children admitted to the Cancer Chemotherapy Unit of the Mofid Children's Hospital, Tehran, Iran were analyzed using conventional biochemical tests and polymerase chain reaction targeting the pehX gene to identify K. oxytoca. The antibiotic susceptibility profile of isolated K. oxytoca against commonly prescribed antibiotics used in treating infection at the facility was determined using the Kirby–Bauer disk diffusion technique. Also, the prevalence of genes encoding toxins among K. oxytoca was identified by PCR assay. Results: The Stool samples of 280 participants were taken for the study of which 38 samples [(55.3% (21/38) 42 males and 44.7% (17/38) females)] tested positive for various Klebsiella spp. Out of this, K. oxytoca was identified in 2.5% (7/280) stools using cultures and conventional biochemical tests. Also, the stools of 2.9% (8/280) of the participants tested positive for K. oxytoca using PCR assay. Using PCR, (2/7) of the K. oxytoca isolates tested positive for the npsA and npsB genes and were identified as toxigenic K. oxytoca strains. Conclusion: The prevalence of toxin‐producing K. oxytoca strains in stool samples of children diagnosed with cancer in Iran is relatively low. Most of the K. oxytoca isolates were susceptible to tested antibiotics. Globally, active surveillance of toxigenic K. oxytoca strains in patients with different malignancies or immunocompromised patients is recommended in healthcare settings. [ABSTRACT FROM AUTHOR]

Patients with cancer have weakened immune systems, making them more vulnerable to infections. This study was carried out to determine the bacterial origins of enteric disorders in cancer patients and noncancer patients at the Oncology Department of Laquintinie Hospital in Douala. A cross‐sectional study was conducted from October 2021 to March 2023. Stool samples from 307 cancer patients with enteric disorders and 200 noncancer patients with enteric disorders were examined to diagnose the presence of bacteria using various techniques. Among all participants in this study, 62.13% were female and 37.87% were male. The average age of the participants was 46.38 ± 15.81 years, with a minimum age of 10 years and a maximum age of 84 years. The average age of participants was significantly higher (p < 0.000) in cancer patients (49.54 ± 14.65 years) compared to noncancer patients (41.53 ± 16.33 years). Proteus mirabilis, Proteus vulgaris, Salmonella typhi, Enterobacter cloacae, Klebsiella pneumoniae, Yersinia intemedia, and Klebsiella oxytoca were more frequently isolated in cancer patients than in noncancer patients, with the respective percentages of 56.25% versus 43.75%, 50.00% versus 50.00%, 61.66% versus 38.34%, 66.66% versus 33.34%, 72.22% versus 27.78%, 80.00 versus 20.00%, and 100% versus 0.00%. Most isolates were sensitive to imipenem (IMP), gentamicin (GEN), and amikacin (AMK). Proteus vulgaris, the most prevalent isolate, showed significantly high resistance (with p < 0.05) in cancer patients compared to noncancer patients at amoxicillin/clavuranic acid (AMC) (89.13% versus 41.30%), ceftriaxone (CTR) (63.04% versus 39.13%), ciprofloxacin (CIP) (65.22% versus 34.18%), and tetracycline (TET) (93.48% versus 63.04%). Multidrug resistance was observed in cancer patients compared to noncancer patients for Klebsiella pneumoniae (85.00% versus 60.00%), Salmonella typhi (84.62% versus 60.00%), and Klebsiella oxytoca (86.49% versus 43.48%). The increase in the number of Gram‐negative infections among cancer patients, as shown in the present study, highlights the need for broad‐spectrum therapy and effective planning of control programs to reduce bacterial diseases among cancer patients. [ABSTRACT FROM AUTHOR]

The problems of toxicity, adverse reactions, high cost and resistance associated with synthetic drugs have created widespread interest in plants as alternative sources of antimicrobial agents, hence the need for scientific assessment of the efficacy of such plant materials. This study evaluated the antimicrobial properties of the ethanol extract of Cinnamomum zeylanicum bark and it's cream formulations. The coarse powder obtained by grinding the dried bark of C. zeylanicum was extracted with 70% ethanol using a Soxhlet extractor. An oil-in-water formulation of the extract as an herbal cream was prepared using the previously described methodology. The antimicrobial activities of the ethanol extract and its cream formulations against some selected bacteria and fungi strains were determined using the agar well diffusion method. The MIC of the extract was determined by the agar dilution method, while the physicochemical properties of the cream were assessed by reference standard protocols. The extract of C. zeylanicum bark and the formulated cream showed comparable concentration-dependent antimicrobial activities to the standard antibiotic (Polymyxin B®), antifungal (Clotrimazole) and combined (triple) action cream (Funbact A®). The MICs were: Staphylococcus aureus (70 mg/ml), Proteus mirabilis (20 mg/ml), Escherichia coli (30 mg/ml), Pseudomonas aeruginosa (110 mg/ml), Klebsiella oxytoca (120 mg/ml) and Entero infections ococcus faecalis (50mg/ml). The physicochemical evaluation of the herbal cream showed that it possesses suitable organoleptic properties of a good cosmetic product. The concentration-dependent broad-spectrum antimicrobial activities exhibited by the crude extract and the cream formulation justify the local use of C. zeylanicum plant in traditional medicine for the treatment of various microbial infections and demonstrate its potential for use in antimicrobial chemotherapy when further developed and formulated in a suitable dosage form. [ABSTRACT FROM AUTHOR]

Introduction: Bacterial vaginosis is the most common outpatient clinical condition in gynecology department; globally Diagnosis of bacterial vaginosis is by amsel's criteria during clinical examination, nugents criteria of gram stain and culture analysis can help to detect the exact pathogen and to start the accurate treatment. The aim of this study is to know the aerobic bacteriology of bacterial vaginosis and their antibiotic susceptibility pattern.Materials and Methods: A total of 363 patients participated in this descriptive cross sectional study was between the age group of 15 to 55 years. Their samples were collected and processed as per guidelines by performing gram stain and culture & sensitivity testing method. Patient details such as age, socioeconomic status, relapse of bacterial vaginosis, number of partners, type of discharge, associated symptoms and signs, and microbiological details were tabulated in an excel sheet to evaluate further. Results: Gram positive cocci are highly susceptible to gentamicin(100%), high level gentam icin(100%), vancomycin(82.8%) followed by linezolid(71.4%), clindamycin(60%), amoxiclav(48.6%) and least sensitive to azithromycin(28.6%). Gram negative bacilli are highly susceptible to amikacin(88.9%), meropenem(85.7%), cefipime(69.2%), followed by piperacillin tazobactam(60%), cotrimoxazole (53.5%), ciprofloxacin (50%), ofloxacin (44.4%), cefotaxime (40.7%), doxycycline (33.3%) and they were least sensitive to ceftriaxone (27.8%). Between the age group of 15 - 28 years, E.coli and Staphylococcus aureus were the most common organism isolated, followed by klebsiella pneumonia, Enterococci, CONS, Candida, Acinetobacter and Klebsiella oxytoca. Between the age group of 29 - 55 years, E.coli was the most common organism isolated, followed by Klebsiella pneumoniae, Enterococci and Staphylococci aureus. Conclusion: This study emphasizes the need to understand the aerobic pathogens associated with vaginitis especially in the reproductive age group to prevent adverse complications seen during pregnancy and labour. [ABSTRACT FROM AUTHOR]

Background: The clinical diagnosis of neonatal sepsis remains difficult because of various challenges, such as culturing the bacteria and avoiding contamination. Therefore, this study aimed to identify bacterial pathogens in patients with clinically diagnosed neonatal sepsis by next-generation sequencing (NGS). Methods: High-throughput NGS and traditional culture identification were performed by comparing samples from newborns with neonatal sepsis with healthy control infants. All blood samples were separately inoculated into anaerobic and aerobic bottles and incubated for 7 days at 37 °C, the positive specimens were then identified. Novel bacteria identified through high-throughput NGS were analysed using polymerase chain reaction (PCR), PCR products were verified by Sanger sequencing. Wilcoxon rank-sum and chi-square tests were performed to assess the significance of differences in species abundance between groups. Subjects were clinically diagnosed and hospitalized at the Pediatrics Department of Shenzhen Seventh People's Hospital and Pediatrics Department of the Longhua Branch of Shenzhen People's Hospital. Experiments were performed at the Shenzhen Seventh People's Hospital. The experimental group comprised 45 newborns clinically diagnosed with neonatal sepsis (age: 0–28 days; 28 males, 17 females). Fifteen normal newborns aged 0–28 days (7 males, 8 females) were included as the control group. Results: High-throughput NGS showed a positivity rate of 44% (20/45) for bacteria in patients clinically diagnosed with neonatal sepsis, whereas traditional bacterial culture identification showed a positivity rate of 0% (0/45). The four main bacterial species identified were Anoxybacillus kestanbolensis, Geobacillus vulcani, Klebsiella oxytoca, and Acinetobacter guillouiae. Conclusions: A. kestanbolensis, G. vulcani, K. oxytoca, and A. guillouiae, newly discovered bacteria in patients with neonatal sepsis, were identified with high-throughput NGS. Which may result from maternal intrauterine infection or birth-canal infection and have a high clinical-cure rate. Owing to a lack of methods to culture these bacteria, their role in neonatal sepsis remains unclear. A definite diagnosis cannot rely solely on bacterial culture identification for patients with a suspected diagnosis and clinical diagnosis of neonatal sepsis and should involve other effective diagnostic techniques. [ABSTRACT FROM AUTHOR]

Purpose: Raoultella spp. is a genus of bacteria that is known to be closely related to Klebsiella. It has been debated whether Raoultella should be reclassified as a subgroup of Klebsiella. The aim of this study is to compare clinical aspects of Raoultella and Klebsiella oxytoca, a species of Klebsiella that is known to be bacteriologically similar to Raoultella spp. Methods: Using data collected at a tertiary care hospital in the United States, we identified 43 patients with Raoultella infection and 1173 patients with Klebsiella oxytoca infection. We compared patient demographics (age and sex), hospitalization status, isolation sites and antibiotic resistance profiles between the two species. Results: There was no significant difference in patient demographics between the two bacteria species. The proportions of intensive care unit (ICU) admission were higher among patients with Raoultella infection (p=0.008). The most common site of isolation was urine for both species (39.5% of all patients with Raoultella spp. vs. 59.3% for K. oxytoca). The second most common site of isolation was blood stream for Raoultella spp. (23.3%) and respiratory tract for K. oxytoca (10.8%). Except for the high proportion of resistant isolates of Raoultella spp. for Trimethoprim/sulfamethoxazole, the antibiotic susceptibility profiles were similar between the two bacteria species. Both were susceptible to ciprofloxacin and meropenem. Conclusion: While there are no significant differences in the patient demographics and antibiotic susceptibility profiles between Raoultella spp. and K. oxytoca, Raoultella may cause more serious infection requiring ICU admissions. Also, Raoultella may cause blood stream infection more frequently than K. oxytoca. [ABSTRACT FROM AUTHOR]

The prevalence and impact of antibiotic-resistant pathogens transmitted through food, particularly street-vended foods, is becoming a major public health concern. Although a significant proportion of the urban population in developing countries consumes street-vended foods, the role of these foods in spreading antibiotic resistance has been rarely investigated. In this study, 50 bacterial isolates were obtained from 25 samples representing five categories of street-vended foods: Phuchka, Chatpati, Sausage, Bun, and Salad. The IMVIC test revealed a notably high occurrence of Escherichia coli (n=32) within the collected samples. Three representative isolates were selected for molecular identification using DNA sequencing of 16S rDNA. They were identified as Klebsiella oxytoca, Burkholderia fungorum, and Serratia nematodiphila. The antibiotic susceptibility of the identified isolates (n=35) was investigated using twelve antibiotics following the Kirby-Bauer disk diffusion method. Around 65.63% of the E. coli isolates (n=21) exhibited multidrug resistance. Double Disc Synergy Test (DDST) and Phenotypic Confirmatory Disk Diffusion Test (PCDDT) confirmed ESBL production of Eight multidrugresistant E. coli isolates (38.09%). The multiple antibiotic resistance (MAR) index showed that 22 E. coli isolates had MAR above 0.2, with resistance mostly against oxacillin, ampicillin, and cefuroxime. The Klebsiella oxytoca isolate showed multidrug resistance viz., ampicillin, oxacillin, cefuroxime, and kanamycin. The Burkholderia fungorum isolate showed no distinct inhibition zone against ampicillin and chloramphenicol. Additionally, the Serratia nematodiphila isolate showed no distinct inhibition zone against three antibiotics, including ampicillin, oxacillin, and cefuroxime. These findings might contribute to the knowledge of emerging antibioticresistant foodborne pathogens and raise concerns about the safety of street-vended foods in Bangladesh. [ABSTRACT FROM AUTHOR]

Background: The human microbiota, K.oxytoca, is resistant to multiple drugs, endangering the lives of patients. Hypervirulent strains evolved into multidrug-resistant strains due to the acquisition of mobile genetic elements. Objectives: To detect the antibiotic-resistant profile and the related virulence genes in the hypervirulent and non-hypervirulent strains isolated from clinical specimens. Materials and methods: A total of 136 clinical samples were collected from patients at Baghdad City Hospitals, Iraq. The isolates were identified, and an antibiotics sensitivity test was carried out. The polymerase chain reaction typing method was used to detect the virulence genes. Results: The most frequent source of K. oxytoca was urine samples (36.03%), then blood samples (15.44%), particularly inpatient samples. About 12.5% of isolates were positive for the hypervirulent test (the string test). Isolates showed variable levels of resistance towards antibiotic groups. The blaCTX-M and aac(6’)-Ib-cr genes were revealed in 88% of isolates, and the blaOXA-48 gene was in 44%. All the tested isolates were negative for the rmpA gene. Conclusion: K. oxytoca is recognized as one of the leading causes of hospital-acquired infections. The rapid identification of antibiotics-resistant, hypervirulent isolates that present a considerable threat to human health is highly recommended in the local hospitals. [ABSTRACT FROM AUTHOR]

Klebsiella spp. are causative agents of healthcare-associated infections in patients who are immunocompromised and use medical devices. The antibiotic resistance crisis has led to an increase in infections caused by these bacteria, which can develop into potentially life-threatening illnesses if not treated swiftly and effectively. Thus, new treatment options for Klebsiella are urgently required. Phage therapy can offer an alternative to ineffective antibiotic treatments for antibiotic-resistant bacteria infections. The aim of the present study was to produce a safe and effective phage cocktail treatment against Klebsiella pneumoniae and Klebsiella oxytoca, both in liquid in vitro culture and an in vivo Galleria mellonella infection model. The phage cocktail was significantly more effective at killing K. pneumoniae and K. oxytoca strains compared with monophage treatments. Preliminary phage cocktail safety was demonstrated through application in the in vivo G. mellonella model: where the phage cocktail induced no toxic side effects in G. mellonella. In addition, the phage cocktail significantly improved the survival of G. mellonella when administered as a prophylactic treatment, compared with controls. In conclusion, our phage cocktail was demonstrated to be safe and effective against Klebsiella spp. in the G. mellonella infection model. This provides a strong case for future treatment for Klebsiella infections, either as an alternative or adjunct to antibiotics. IMPORTANCE Klebsiella infections are a concern in individuals who are immunocompromised and are becoming increasingly difficult to treat with antibiotics due to their drug-resistant properties. Bacteriophage is one potential alternative therapy that could be used to tackle these infections. The present study describes the design of a non-toxic phage cocktail that improved the survival of Galleria mellonella infected with Klebsiella. This phage cocktail demonstrates potential for the safe and effective treatment of Klebsiella infections, as an adjunct or alternative to antibiotics. [ABSTRACT FROM AUTHOR]

The challenge in polystyrene disposal has caused researchers to look for urgent innovative and ecofriendly solutions for plastic degradation. Some insects have been reported to use polystyrene as their sole carbon source, and this has been linked to the presence of microbes in their guts that aid in plastic digestion. Thus, this study focuses on the molecular detection and phylogenetic analysis of the alkane-1-monooxygenase (alkB) gene in Klebsiella oxytoca strains isolated from the gut of Tenebrio molitor. The alkB gene encodes for alkane-1-monooxygenase, an enzyme involved in the oxidation of inactivated alkanes. This gene can be used as a marker to assess bacteria's ability to biodegrade polystyrene. Three bacterial strains were isolated from the guts of T. molitor mealworms and were confirmed using polymerase chain reaction (PCR) of the 16S ribosomal RNA gene. The primers used in the amplification of the 16S ribosomal RNA region were designed using NCBI, a bioinformatics tool. To detect the presence of the alkB gene in the isolated bacterial strains, a set of primers used in the amplification of this gene was manually designed from the conserved regions of the alkB nucleotide sequences of eleven bacterial species from GenBank. TCOFFE online tool was used to align the alkB sequences of the bacteria, while Jalview and ConSurf were used to view the alignment. The amplified alkB gene was then sequenced using the Sanger sequencing technique, blasted on NCBI to look for similar sequences, and a phylogenetic tree was constructed. Based on the 16S ribosomal RNA gene sequences, the isolated bacterial strains were confirmed to be Klebsiella oxytoca NBRC 102593, Klebsiella oxytoca JCM 1665, and Klebsiella oxytoca ATCC 13182. The alkB gene sequence identical to fourteen alkB gene sequences derived from Actinobacteria whole genome was detected in Klebsiella oxytoca for the first time to the best of our knowledge. The novel nucleotide sequence was published in the NCBI database under accession number OP959069. This gene sequence was found to be for the enzyme alkane-1-monooxygenase and may be one of the enzymes responsible for polystyrene degradation by the putative Klebsiella oxytoca ATCC 13182 in T. molitor. [ABSTRACT FROM AUTHOR]