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Colistin is one of the last-line treatments for multi-drug resistant Gram-negative bacterial infections. The emergence of mobile colistin resistance genes has driven global concern and triggered the need for surveillance. Our report reveals the identification of mcr-9.1 and mcr-10.1 in Ecuador by employing a proximity ligation technique.

Carbapenem-resistant Enterobacterales (CRE) have become a global threat, with colistin being the last resort for treatment. CLSI and EUCAST recommend broth microdilution (BMD) as the reference method for colistin susceptibility testing. Nordmann and Poirel have developed a simple and rapid Polymyxin NP test as an alternative to BMD for screening of colistin-resistant Enterobacterale (CoRE) isolates. This study aimed to evaluate the performance of the colistin rapid NP (CRNP) test for the detection of colistin resistance. CRNP test was performed on thirty-one clinical Enterobacterales isolates [ Klebsiella pneumoniae (21), Enterobacter spp , (9) and Escherichia coli (1), which were resistant to Colistin by the reference BMD method. The results of the NP test were interpreted after 4hr by the change in color of NP solution (original orange to yellow as a result of bacterial growth) and compared with that of BMD. The CRNP test could accurately detect 26/31 of the colistin resistant Enterobacterale isolates, and thus had an overall categorical agreement of 83.8%. Out of thirty-one CoRE isolates, five Enterobacter spp. 5/31 (16.1%) could not be detected by the CRNP test giving a false-negative result. Excluding those five Enterobacter spp. the categorical agreement (CA) of the CRNP test with BMD was 100%. The overall very major error (VME) of the CRNP test was 16% but decreased to < 3% when Enterobacter spp. (5) were excluded. The CRNP test is technically less demanding, yields faster results compared to the reference BMD method, and has 100% agreement with reference BMD in Enterobacterales except for Enterobacter spp. [ABSTRACT FROM AUTHOR]

Background: Bacterial growth rate, commonly reported in terms of doubling time, is frequently determined by one of two techniques: either by measuring optical absorption of a growing culture or by taking samples at different times during their growth phase, diluting them, spreading them on agar plates, incubating them, and counting the colonies that form. Both techniques require measurements of multiple repeats, as well careful assessment of reproducibility and consistency. Existing literature using either technique gives a wide range of growth rate values for even the most extensively studied species of bacteria, such as Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. This work aims to apply several methods to reliably determine the growth rate of a recently identified species of Enterobacteriaceae, called Enterobacter sp. SM3, and to compare that rate with that of a well-known wildtype E. coli strain KP437. Results: We extend conventional optical density (OD) measurements to determine the growth rate of Enterobacter sp. SM3. To assess the reliability of this technique, we compare growth rates obtained by fitting the OD data to exponential growth, applying a relative density method, and measuring shifts in OD curves following set factors of dilution. The main source of error in applying the OD technique is due to the reliance on an exponential growth phase with a short span. With proper choice of parameter range, however, we show that these three methods yield consistent results. We also measured the SM3 division rate by counting colony-forming units (CFU) versus time, yielding results consistent with the OD measurements. In lysogeny broth at 37oC, SM3 divides every 21 ± 3 min, notably faster than the RP437 strain of E. coli, which divides every 29 ± 2 min. Conclusion: The main conclusion of this report is that conventional optical density (OD) measurements and the colony-forming units (CFU) method can yield consistent values of bacterial growth rate. However, to ensure the reproducibility and reliability of the measured growth rate of each bacterial strain, different methods ought to be applied in close comparison. The effort of checking for consistency among multiple techniques, as we have done in this study, is necessary to avoid reporting variable values of doubling time for particular species or strains of bacteria, as seen in the literature. [ABSTRACT FROM AUTHOR]

In this study, a method of removing uranium from wastewater using Pseudomonas and Enterobacter in indigenous bacterial communities was proposed and demonstrated good removal efficiency. Biological mechanisms were employed to investigate the removal mechanism. The results suggested that the indigenous bacterial community can transform soluble uranyl ions to insoluble uranium-containing precipitates and fix them on the ore surface. Furthermore, hydroxyl, carboxyl, phosphate groups, and proteins of microorganisms were identified as crucial roles in the uranium removal process. These findings reveal the significant potential application value of the indigenous bacterial community for the remediation of uranium wastewater from decommissioned mining areas. [ABSTRACT FROM AUTHOR]

Lignin, the second most abundant renewable carbon source on earth, holds significant potential for producing biobased specialty chemicals. However, its complex, highly branched structure, consisting of phenylpropanoic units and strong carbon-carbon and ether bonds, makes it highly resistant to depolymerisation. This recalcitrancy highlights the need to search for robust lignin-degrading microorganisms with potential for use as industrial strains. Bioprospecting for microorganisms from lignin-rich niches is an attractive approach among others. Here, we explored the ligninolytic potential of bacteria isolated from a lignin-rich underground coalmine, the Morupule Coal Mine, in Botswana. Using a culture-dependent approach, we screened for the presence of bacteria that could grow on 2.5% kraft lignin-supplemented media and identified them using 16 S rRNA sequencing. The potential ligninolytic isolates were evaluated for their ability to tolerate industry-associated stressors. We report the isolation of twelve isolates with ligninolytic abilities. Of these, 25% (3) isolates exhibited varying robust ligninolytic ability and tolerance to various industrial stressors. The molecular identification revealed that the isolates belonged to the Enterobacter genus. Two of three isolates had a 16 S rRNA sequence lower than the identity threshold indicating potentially novel species pending further taxonomic review. ATR-FTIR analysis revealed the ligninolytic properties of the isolates by demonstrating structural alterations in lignin, indicating potential KL degradation, while Py-GC/MS identified the resulting biochemicals. These isolates produced chemicals of diverse functional groups and monomers as revealed by both methods. The use of coalmine-associated ligninolytic bacteria in biorefineries has potential. [ABSTRACT FROM AUTHOR]

Carbapenem-resistance in Enterobacter spp due to acquisition of mobile carbapenemases is of concern. An Enterobacter spp grew on ChromID CARBA medium and was positive for the mCIM carbapenemase detection assay. Susceptibility testing showed resistance to aztreonam and reduced susceptibility to imipenem. Conventional PCR using FRI primers detected a blaFRI gene. Whole genome sequencing reveled a new variant; blaFRI−12 was closest in sequence to blaFRI−5 differing by 13 amino acids and was found on a unique 110Kb IncR plasmid. Given the intrinsic nature of Enterobacter spp. to be carbapenem non-susceptible, blaFRI-types may be under reported globally. [ABSTRACT FROM AUTHOR]

Acetaminophen [N-(4-hydroxyphenyl) acetamide, APAP] is an extensively and frequently consumed over-the-counter analgesic and antiphlogistic medication. It is being regarded as an emerging pollutant due to its continuous increment in the environment instigating inimical impacts on humans and the ecosystem. Considering its wide prevalence in the environment, there is an immense need of appropriate methods for the removal of APAP. The present study indulged screening and isolation of APAP degrading bacterial strains from pharmaceuticals-contaminated sites, followed by their molecular characterization via 16S rRNA sequencing. The phylogenetic analyses assigned the isolates to the genera Pseudomonas, Bacillus, Paracoccus, Agrobacterium, Brucella, Escherichia, and Enterobacter based on genetic relatedness. The efficacy of these strains in batch cultures tested through High-performance Liquid Chromatography (HPLC) revealed Paracoccus sp. and Enterobacter sp. as the most promising bacterial isolates degrading up to 88.96 and 85.92%, respectively of 300 mg L−1 of APAP within 8 days of incubation. Michaelis–Menten kinetics model parameters also elucidated the high degradation potential of these isolates. The major metabolites identified through FTIR and GC–MS analyses were 4-aminophenol, hydroquinone, and 3-hydroxy-2,4-hexadienedioic. Therefore, the outcomes of this comprehensive investigation will be of paramount significance in formulating strategies for the bioremediation of acetaminophen-contaminated sites through a natural augmentation process via native bacterial strains. [ABSTRACT FROM AUTHOR]

Colistin resistance poses a major therapeutic challenge and resistant strains have now been reported worldwide. However, the occurrence of such bacteria in aquatic environments is considerably less understood. This study aimed to isolate and characterize colistin-resistant strains from water and plastic litter collected in an urban recreational estuary. Altogether, 64 strains with acquired colistin resistance were identified, mainly Acinetobacter spp. and Enterobacter spp. From these, 40.6% were positive for at least one mcr variant (1–9), 26.5% harbored, extended-spectrum beta-lactamases, 23.4% harbored, sulfonamide resistance genes, and 9.3% harbored, quinolone resistance genes. merA , encoding mercury resistance, was detected in 10.5% of these strains, most of which were also strong biofilm producers. The minimum inhibitory concentration toward colistin was determined for the mcr -positive strains and ranged from 2 to ≥512 µg ml−1. Our findings suggest that Gram-negative bacteria highly resistant to a last-resort antimicrobial can be found in recreational waters and plastic litter, thereby evidencing the urgency of the One Health approach to mitigate the antimicrobial resistance crisis. [ABSTRACT FROM AUTHOR]

Phosphorus (P) solubilization is one of the major traits for plant growth-promoting rhizobacteria since P is easily rendered insoluble in soil. Phosphate-solubilizing microorganisms can be harnessed as an environment-friendly strategy to enhance the mobilization and acquisition of P by crops. Utilization of such microorganisms as microbial inoculants in agriculture serves as an alternative to chemical fertilizers and an approach for more efficient P fertilization. Hence, this study aims to characterize a phosphate-solubilizing isolate and evaluate its potential as a microbial inoculant. Morphological, biochemical, and genetic characterization of the isolate were performed. Then, the mineral phosphate solubilization ability of the isolate was evaluated. Lastly, this study evaluated the plant growth promotion of the isolate as a single inoculant in rice or as a co-inoculant with rhizobia in peanuts. On the basis of biochemical and 16S rRNA analysis, the isolate was identified as Enterobacter sp. Also, it can solubilize P from tricalcium phosphate or aluminum phosphate. Simultaneous with P solubilization, medium acidification, and gluconic acid secretion were observed. Lastly, the Enterobacter sp. isolate could potentially be developed as a biofertilizer in reducing P resource input or to enhance the performance of a rhizobia inoculant. [ABSTRACT FROM AUTHOR]

Aim This study aimed to screen and characterize colistin-resistant strains isolated from different livestock species in Algeria, including sheep, goats, and dromedaries. Methods and results A total of 197 rectal and nasal swabs were screened for colistin-resistant Gram-negative bacilli. Twenty one isolates were selected, identified, and their antibiotic resistance was phenotypically and genotypically characterized. The majority (15/21) were affiliated to Escherichia coli , from which 4 strains isolated from sheep (n  = 2) and goats (n  = 2) and belonging to phylogroup A and ST10 and ST6396 lineages, respectively, carried the mcr -1 gene. The remaining isolates were identified as belonging to the following genera: Raoultella, Enterobacter, Klebsiella , and Pseudomonas. Conclusion This study highlights the presence of virulent and multiresistant Gram-negative bacilli in farm animals, increasing the risk of transmitting potentially fatal infections to humans. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the microbiological quality of coconut water sold from street carts equipped with cooling coils or refrigerated at bakeries in the Grande Vitória Region, Brazil. Additionally, it assessed the phenotypic and genotypic antimicrobial resistance profiles of isolated enterobacteria. The results indicated that coconut water sold at street carts had lower microbiological quality compared to refrigerated samples, as evidenced by significantly higher counts of mesophilic microorganisms. Using MALDI-TOF, the following opportunistic pathogens were identified: Citrobacter freundii, Enterobacter bugandensis, E. kobei, E. roggenkampii, Klebsiella pneumoniae, and Kluyvera ascorbata. Three isolates—E. bugandensis, K. pneumoniae, and K. ascorbata—were classified as multidrug-resistant (MDR). Widespread resistance to β-lactams and cephalosporins was detected, and some isolates were resistant to quinolones, nitrofurans, and phosphonic acids. The gene blaCTX-M-2 was detected in C. freundii, E. bugandensis, E. kobei, and K. ascorbata. However, genes blaNDM, blaKPC, blaCMY-1, and blaCMY-2 were not detected in any isolate. The findings underscore the need to enhance good manufacturing practices in this sector to control the spread of antimicrobial resistance (AMR). To our knowledge, this is the first study documenting the presence of potentially pathogenic enterobacteria in coconut water samples and their associated phenotypic and genotypic AMR profiles. [ABSTRACT FROM AUTHOR]

We analyzed the whole genome sequences (WGS) and antibiograms of 35 Enterobacter isolates, including E. hormaechei and E. asburiae, and the recently described E. bugandensis, E. kobei, E. ludwigii, and E. roggenkampii species. Isolates were obtained from human blood and urinary tract infections in patients in the United States. Our goal was to understand the genetic diversity of antimicrobial resistance genes and virulence factors among the various species. Thirty-four of 35 isolates contained an AmpC class blaACT allele; however, the E. roggenkampii isolate contained blaMIR-5. Of the six Enterobacter isolates resistant to ertapenem, imipenem, and meropenem, four harbored a carbapenemase gene, including blaKPC or blaNDM. All four isolates were mCIM-positive. The remaining two isolates had alterations in ompC genes that may have contributed to the resistance phenotype. Interpretations of cefepime test results were variable when disk diffusion and automated broth microdilution results were compared due to the Clinical Laboratory and Standards Institute use of the "susceptible dose-dependent" classification. The diversity of the blaACT alleles paralleled species identifications, as did the presence of various virulence genes. The classification of recently described Enterobacter species is consistent with their resistance gene and virulence gene profiles. [ABSTRACT FROM AUTHOR]

The current study focused on the exploration of bacterial community in heavy metal contaminated soil using culture dependent and independent approaches that might be applied to the bioremediation process. A total of 150 bacterial colonies were examined from the heavy metal-contaminated soil at initial level, and 25 isolates were chosen for further examination. Finally, twelve strains were chosen for future research based on their high levels of heavy metal resistance. The 10 bacterial strains i.e.,1K-10K were then characterized on the basis of their morphology and microscopic analysis. The morphological and biochemical characteristic relied on the basis of Bergey's manual of bacterial classification that 1K as Pseudomonas sp., 2K as Enterobacter sp., 3K as Streptococcus sp., 4K as Staphylococcus sp.,5K as Staphylococcus sp., 6K as Pseudomonas sp., 7K as Micrococcus sp., 8K as Staphylococcus sp., 9K as Staphylococcus sp. & 10K as Staphylococcus sp. In metagenomics analysis, the most prevalent bacteria present in samples were "Actinobacteria, Proteobacteria, Acidobacteria, Pseudomonas Cyanobacteria, Bacteriodes, and Sphingomonas. Among the 29 identified phyla, Chloroflexi and Tenericutes were the most dominant phyla and their relative abundance ranged from 0.75-1.00. While, on the genera level, the most abundant genera were Blautia, Rhodoplanes followed by Prevotella and Arenimonas. The relative abundance of these genera ranged from 0.75% to 1.00%. Depending on the relative abundance of taxons, the results of this study showed Proteobacteria, Synergistetes and Bacteriodes were most abundant phylum while the least abundant phylum present in heavy metal contaminated soil was Chlamydia and Tenericutes. Screening of soil-based libraries using functional and sequence-based specifications, which has disclosed information on soil microbial communities, has made it possible to identify new microbial communities. Thus, the culture dependent and independent approaches revealed that even heavy metal contaminated soil compose of diverse group of bacterial community that could be explored for bioremediation purposes. [ABSTRACT FROM AUTHOR]

Phosphorus (P) solubilization is one of the major traits for plant growth-promoting rhizobacteria since P is easily rendered insoluble in soil. Phosphate-solubilizing microorganisms can be harnessed as an environment-friendly strategy to enhance the mobilization and acquisition of P by crops. Utilization of such microorganisms as microbial inoculants in agriculture serves as an alternative to chemical fertilizers and an approach for more efficient P fertilization. Hence, this study aims to characterize a phosphate-solubilizing isolate and evaluate its potential as a microbial inoculant. Morphological, biochemical, and genetic characterization of the isolate were performed. Then, the mineral phosphate solubilization ability of the isolate was evaluated. Lastly, this study evaluated the plant growth promotion of the isolate as a single inoculant in rice or as a co-inoculant with rhizobia in peanuts. On the basis of biochemical and 16S rRNA analysis, the isolate was identified as Enterobacter sp. Also, it can solubilize P from tricalcium phosphate or aluminum phosphate. Simultaneous with P solubilization, medium acidification, and gluconic acid secretion were observed. Lastly, the Enterobacter sp. isolate could potentially be developed as a biofertilizer in reducing P resource input or to enhance the performance of a rhizobia inoculant.

Introduction: Enterobacter chengduensis was defined as a novel species in the genus. Enterobacter in 2019, however, antimicrobial resistance, such as carbapenem resistance, has rarely been described in E. chengduensis. This study described the molecular features of four carbapenem-resistant E. chengduensis strains collected from a tertiary health care hospital in Southwest China. Methods: Whole genome sequencing (WGS) was used to determine the genome sequence of four E. chengduensis strains. The precise species of strains were identified by average nucleotide identity (ANI) and in silico DNADNA hybridization (isDDH). The clonal relatedness of four E. chengduensis strains and additional 15 ones from NCBI were examined through phylogenetic analysis. The molecular features of E. chengduensis and genetic structure of carbapenemase-encoding plasmids were characterized through genomic annotation and analysis. Results: The results revealed the emergence of blaNDM-1-carrying E. chengduensis strains in China. Multilocus sequence typing (MLST) analysis showed that all 19 E. chengduensis belonged to the same sequence type of ST414. Core SNP analysis suggested the potential intrahospital clonal transmission of ST414 E. chengduensis. The carbapenemase-encoding gene blaNDM-1 was harbored by an IncC-type plasmid, which was experimentally confirmed to be able to conjugate. Discussion: This study reports the first emergence and potential clonal transmission of blaNDM-1-carrying E. chengduensis. Further surveillance should be advocated to monitor the dissemination of carbapenem-resistant E. chengduensis and blaNDM-1-harboring IncC-type plasmids in China. [ABSTRACT FROM AUTHOR]

β-Lactam antibiotics are a class of antibiotics commonly used to treat bacterial infections. However, the effects of β-lactam antibiotics on term neonatal intestinal flora have not been fully elucidated. Hospitalized full-term newborns receiving β-lactam antibiotics formed the antibiotic group (n = 67), while those without antibiotic treatment comprised the non-antibiotic group (n = 47). A healthy group included healthy full-term newborns (n = 16). Stool samples were collected for 16 S rDNA sequencing to analyze gut microbiota variations. Further investigation was carried out within the β-lactam antibiotic group, exploring the effects of antibiotic use on the newborns' gut microbiota in relation to the duration and type of antibiotic administration, delivery method, and feeding practices. The antibiotic group exhibited significant difference of microbial community composition compared to the other groups. Genera like Klebsiella, Enterococcus, Streptococcus, Alistipes, and Aeromonas were enriched, while Escherichia-Shigella, Clostridium sensu stricto 1, Bifidobacterium, and Parabacteroides were reduced. Klebsiella negatively correlated with Escherichia-Shigella, positively with Enterobacter, while Escherichia-Shigella negatively correlated with Enterococcus and Streptococcus. Regardless of neonatal age, β-lactam antibiotics induced an elevated abundance of Klebsiella and Enterococcus. The impact on gut microbiota varied with the duration and type of antibiotic (cefotaxime or ampicillin/sulbactam). Compared to vaginal delivery, cesarean delivery after β-lactam treatment heightened the abundance of Klebsiella, Enterobacteriaceae_Unclassified, Lactobacillales_Unclassified, and Pectobacterium. Feeding patterns minimally influenced β-lactam-induced alterations. In conclusion, β-lactam antibiotic treatment for neonatal pneumonia and sepsis markedly disrupted intestinal microbiota, favoring Klebsiella, Enterococcus, Streptococcus, Alistipes, and Aeromonas. The impact of β-lactam varied by duration, type, and delivery method, emphasizing heightened disruptions post-cesarean delivery. [ABSTRACT FROM AUTHOR]

Antibiotic resistance has emerged as a global threat to public health, generating a growing interest in investigating the presence of antibiotic-resistant bacteria in environments influenced by anthropogenic activities. Wastewater treatment plants in hospital serve as significant reservoirs of antimicrobial-resistant bacteria, where a favorable environment is established, promoting the proliferation and transfer of resistance genes among different bacterial species. In our study, we isolated a total of 243 strains from 5 hospital wastewater sites in Mexico, belonging to 21 distinct Gramnegative bacterial species. The presence of β-lactamase was detected in 46.9% (114/243) of the isolates, which belonging to the Enterobacteriaceae family. We identified a total of 169 β-lactamase genes; blaTEM in 33.1%, blaCTX-M in 25.4%, blaKPC in 25.4%, blaNDM 8.8%, blaSHV in 5.3%, and blaOXA-48 in 1.1% distributed in 12 different bacteria species. Among the 114 of the isolates, 50.8% were found to harbor at least one carbapenemase and were discharged into the environment. The carbapenemase blaKPC was found in six Citrobacter spp. and E. coli, while blaNDM was detected in two distinct Enterobacter spp. and E. coli. Notably, blaNDM-1 was identified in a 110 Kb IncFII conjugative plasmid in E. cloacae, E. xiangfangensis, and E. coli within the same hospital wastewater. In conclusion, hospital wastewater showed the presence of Enterobacteriaceae carrying a high frequency of carbapenemase blaKPC and blaNDM. We propose that hospital wastewater serves as reservoirs for resistance mechanism within bacterial communities and creates an optimal environment for the exchange of this resistance mechanism among different bacterial strains. [ABSTRACT FROM AUTHOR]

Infections caused by multidrug-resistant (MDR) bacteria are a growing global concern. Enterobacter cloacae complex (ECC) species are particularly adept at developing antibiotic resistance. Phage therapy is proposed as an alternative treatment for pathogens that no longer respond to antibiotics. Unfortunately, ECC phages are understudied when compared to phages of many other bacterial species. In this Ghanaian-Finnish study, we isolated two ECC strains from ready-to-eat food samples and three novel phages from natural waters against these strains. We sequenced the genomic DNA of the novel Enterobacter phages, fGh-Ecl01, fGh-Ecl02, and fGh-Ecl04, and assessed their therapeutic potential. All of the phages were found to be lytic, easy to propagate, and lacking any toxic, integrase, or antibiotic resistance genes and were thus considered suitable for therapy purposes. They all were found to be related to T4-type viruses: fGh-Ecl01 and fGh-Ecl04 to karamviruses and fGh-Ecl02 to agtreviruses. Testing of Finnish clinical ECC strains showed promising susceptibility to these novel phages. As many as 61.1% of the strains were susceptible to fGh-Ecl01 and fGh-Ecl04, and 7.4% were susceptible to fGh-Ecl02. Finally, we investigated the susceptibility of the newly isolated ECC strains to three antibiotics – meropenem, ciprofloxacin, and cefepime – in combination with the novel phages. The use of phages and antibiotics together had synergistic effects. When using an antibiotic-phage combination, even low concentrations of antibiotics fully inhibited the growth of bacteria. [ABSTRACT FROM AUTHOR]

The family of ESKAPE pathogens is comprised of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter. Together they are the main contributors of nosocomial infections and are well established for their ability to "escape" antibiotics. Farnesol is an FDA-approved cosmetic and flavoring agent with significant anti-biofilm properties. In a proprietary emulsion, farnesol has been shown to be capable of disrupting S. aureus, P. aeruginosa, and A. baumannii biofilms. The current work demonstrates that this farnesol emulsion reduces the number of viable bacteria, while also leading to reductions in biomass, of the other three ESKAPE pathogens: Enterococcus faecium, Klebsiella pneumoniae, and Enterobacter, both in vitro and in an ex vivo human skin model. A concentration of 0.5 mg/mL was effective for impeding biofilm development of all three bacteria, while 1 mg/mL for E. faecium and K. pneumoniae, or 0.2 mg/mL for E. cloacae, was able to kill bacteria in established biofilms. Contrary to antibiotics, no resistance to farnesol was observed for E. faecium or K. pneumoniae. The results indicate that farnesol is effective for direct cell killing and also has the ability to induce biofilm detachment from surfaces, as confirmed using Live/Dead image analysis. Our findings confirm that farnesol emulsion is an effective broad-spectrum agent to impede ESKAPE biofilms. [ABSTRACT FROM AUTHOR]

The paper presents an attempt to explain the potential mechanisms related to the biocontrol capacity of the four strains representing bacterial species in which this activity was observed for the first time (Pseudomonas vancouverensis L16, Pseudomonas chlororaphis subsp. aureofaciens 3M, Enterobacter ludwigii 43M and Pseudomonas protegens 59M). The P. protegens 59M strain showed the highest effectiveness in protecting pear fruitlets against fire blight. The phenotypic analyses of tested mechanisms showed that all strains demonstrated the ability of motility, hydrogen cyanide production and degradation of nicotinic acid. Also, all strains except E. ludwigii 43M, produced siderophores and P. vancouverensis L16 was able to produce biosurfactant, salicylic acid and indole-3-acetic acid (IAA) while the E. ludwigii 43M and P. chlororaphis subsp. aureofaciens 3M strains produced IAA and homoserine lactones (AHL), respectively. A study on the detection of genes encoding antibiotics characteristic of pseudomonads showed the presence of prnD in the P. chlororaphis subsp. aureofaciens 3M strain and phlD, pltC, pltB and pltC in P. protegens 59M, which suggested that the latter strain had the largest number of antibiotic-coding genes among all the strains tested. The regulatory gene gacA was also present in P. protegens 59M and P. chlororaphis subsp. aureofaciens 3M strains. However, none of the genes sought were detected in the L16 strain. It was assumed that the ability of strain P. protegens 59M to completely protect slices of pear fruitlet against E. amylovora infection is related to the production of antibiotics and possibly also to the other detected mechanisms of antagonism, such as siderophore, IAA and HCN production. [ABSTRACT FROM AUTHOR]

Triadimefon, a type of triazole systemic fungicide, has been extensively used to control various fungal diseases. However, triadimefon could lead to severe environmental pollution, and even threatens human health. To eliminate triadimefon residues, a triadimefon-degrading bacterial strain TY18 was isolated from a long-term polluted site and was identified as Enterobacter hormaechei. Strain TY18 could grow well in a carbon salt medium with triadimefon as the sole nitrogen source, and could efficiently degrade triadimefon. Under triadimefon stress, a total of 430 differentially expressed genes (DEGs), including 197 up-regulated and 233 down-regulated DEGs, were identified in strain TY18 using transcriptome sequencing (RNA-Seq). Functional classification and enrichment analysis revealed that these DEGs were mainly related to amino acid transport and metabolism, carbohydrate transport and metabolism, small molecule and pyrimidine metabolism. Interestingly, the DEGs encoding monooxygenase and hydrolase activity acting on carbon–nitrogen were highly up-regulated, might be mainly responsible for the metabolism in triadimefon. Our findings in this work suggest that strain E. hormaechei TY18 could efficiently degrade triadimefon for the first time. They provide a great potential to manage triadimefon biodegradation in the environment successfully. [ABSTRACT FROM AUTHOR]

Background: Enterobacter cloacae complex (ECC) including different species are isolated from different human clinical samples. ECC is armed by many different virulence genes (VGs) and they were also classified among ESKAPE group by WHO recently. The present study was designed to find probable association between VGs and antibiotic susceptibility in different ECC species. Methods: Forty-five Enterobacter isolates that were harvested from different clinical samples were classified in four different species. Seven VGs were screened by PCR technique and antibiotic susceptibility assessment was performed by disk-diffusion assay. Result: Four Enterobacter species; Enterobacter cloacae (33.3%), Enterobacter hormaechei (55.6%), Enterobacter kobei (6.7%) and Enterobacter roggenkampii (4.4%) were detected. Minimum antibiotic resistance was against carbapenem agents and amikacin even in MDR isolates. 33.3% and 13.3% of isolates were MDR and XDR respectively. The rpoS (97.8%) and csgD (11.1%) showed maximum and minimum frequency respectively. Blood sample isolated were highly virulent but less resistant in comparison to the other sample isolates. The csgA, csgD and iutA genes were associated with cefepime sensitivity. Conclusion: The fepA showed a predictory role for differentiating of E. hormaechei from other species. More evolved iron acquisition system in E. hormaechei was hypothesized. The fepA gene introduced as a suitable target for designing novel anti-virulence/antibiotic agents against E. hormaechei. Complementary studies on other VGs and ARGs and with bigger study population is recommended. [ABSTRACT FROM AUTHOR]

Simple Summary: This study was undertaken to determine the gut microbiota of six species of the Telenomus genus (T. alecto, T. sulculus, T. fariai, T. remus, T. podisi, and T. lobatus). Wasp parasitoids were collected from their hosts in different locations in Mexico. DNA was extracted from gut collection, and sequencing of bacterial 16S rRNA was carried out in Illumina® MiSeq™. Among the six species of wasps, results showed that the most abundant phylum were Proteobacteria (82.3%), Actinobacteria (8.1%), and Firmicutes (7.8%). The most important genera were Delftia and Enterobacter. Seventeen bacteria species were found to be shared among the six species of wasps. Bacterial symbionts in insects constitute a key factor for the survival of the host due to the benefits they provide. Parasitoid wasps are closely associated with viruses, bacteria, and fungi. However, the primary symbionts and their functions are not yet known. This study was undertaken to determine the gut microbiota of six species of the Telenomus genus: T. alecto (Crawford), T. sulculus Johnson, T. fariai Costa Lima, T. remus Nixon, T. podisi Ashmead, and T. lobatus Johnson & Bin. Wasp parasitoids were collected from their hosts in different locations in Mexico. DNA was extracted from gut collection, and sequencing of bacterial 16S rRNA was carried out in Illumina® MiSeq™. Among the six species of wasps, results showed that the most abundant phylum were Proteobacteria (82.3%), Actinobacteria (8.1%), and Firmicutes (7.8%). The most important genera were Delftia and Enterobacter. Seventeen bacteria species were found to be shared among the six species of wasps. The associate microbiota will help to understand the physiology of Telenomus to promote the use of these wasp parasitoids in the management of insect pests and as potential biomarkers to target new strategies to control pests. [ABSTRACT FROM AUTHOR]

Most bacterial species synthesize extracellular polymeric substances (EPS) with diverse compositional, structural, and functional characteristics. When under sustained hydrodynamic flow, bacteria form streamers, which are filamentous matrix structures porous in nature. So far, investigations on streamers have been limited to pure culture bacterial species, overlooking the aggregate nature of bacterial flocs and biofilms. The aim of this work is to analyze the effects of the cultivation conditions (controlling the EPS synthesis), the hydrodynamics, and the bacterial species type on streamer formation by pure and mixed culture using microfluidic separators. Enterobacter A47 (EPS-producing bacterium) and Cupriavidus necator (non-EPS producing bacterium) are used for the experimental work. It has been found that the EPS secreted by the bacteria and flow conditions play a very significant role in streamer formation dynamics. Strong flow conditions (i.e., high flow rates and small constrictions with tortuous architecture) favor the fast development of streamers, whereas intermediate flow rates result in sustained growth for longer filtration times, leading to dense streamers. Our analysis confirms that the presence of EPS in the bacterial suspension critically controls streamer formation by forming bacterial aggregates, or flocs, and bridging between different aggregates. We also found that streamer formation is significantly enhanced with mixed bacterial culture, which may be attributed to the symbiotic relationships influencing the concentration and characteristics of EPS and the material behavior in general. [ABSTRACT FROM AUTHOR]

Background: Unlike plant phytochemicals, little has been done to explore the metabolites from phyllosphere bacterial flora, some of which enabled them to survive interspecific competition through amensalism. This study evaluated the antimicrobial activity of metabolites from Phyllospheric Bacteria (PB) isolated from Funtumia elastica (FE), against selected bacterial and fungal pathogens. Phenotypic and molecular methods were used to identify the isolated phyllo-microbiota. Methods: The PB were aseptically isolated by sonication. Their metabolites were obtained from the fresh overnight culture of the organisms. The cell-free supernatants containing the metabolites were used for antimicrobial assays against the pathogens. The DNA of the bacterial isolates were isolated using a NIMR-BIOTECH DNA extraction kit, while their 16S rRNA was amplified with the primer: 799F 5'-AACACGGATTA GATACC-3', 1193R 5'- ACGTCATCCCCACCTTCC-3', using SolisFast* Master Mix, (Solis Biodyne-Estonia). The BLAST of the sequence was done from the NCBI Genbank. The PB strains identified were submitted to NCBI and accession numbers were assigned to them. Results: The phyllosphere of FE yielded 21 bacterial isolates: 7 Gram-positives and 14 Gram-negatives. The metabolites from these isolates showed varying degrees of bioactivity against Staphylococcus aureus (ATCC29213), Escherichia coli (ATCC 25922) Klebsiella pneumoniae (ATCC 35659); Trychophyton rubrum, Candida albicans and Microsporum canis. Fifteen bioactive isolates sequenced yielded four genera, Enterobacter (E. hormaechei 98.44%), Bacillus (B. cereus 100%), Pontoea (P. dispersa 99.72%), Staphylococcus (S. arlettae 99.72%). Conclusion: Bacteria from FE phyllosphere, produced metabolites antagonistic (cidal) to some human pathogens. This has great potential for possible drug discovery. [ABSTRACT FROM AUTHOR]

Enterobacter hormaechei, one of the species within the Enterobacter cloacae complex, is a relevant agent of healthcare-associated infections. In addition, it has gained relevance because isolates have shown the capacity to resist several antibiotics, particularly carbapenems. However, knowledge regarding colonization and virulence mechanisms of E. hormaechei has not progressed to the same extent as other Enterobacteriaceae species as Escherichia coli or Klebsiella pneumoniae. Here, we describe the presence and role of the type 3 fimbria, a chaperone-usher assembled fimbria, which was first described in Klebsiella spp., and which has been detected in other representatives of the Enterobacteriaceae family. Eight Chilean E. cloacae isolates were examined, and among them, four E. hormaechei isolates were found to produce the type 3 fimbria. These isolates were identified as E. hormaechei subsp. hoffmannii, one of the five subspecies known. A mutant E. hormaechei subsp. hoffmannii strain lacking the mrkA gene, encoding the major structural subunit, displayed a significantly reduced adherence capacity to a plastic surface and to Caco-2 cells, compared to the wild-type strain. This phenotype of reduced adherence capacity was not observed in the mutant strains complemented with the mrkA gene under the control of an inducible promoter. Therefore, these data suggest a role of the type 3 fimbria in the adherence capacity of E. hormaechei subsp. hoffmannii. A screening in E. hormaechei genomes contained in the NCBI RefSeq Assembly database indicated that the overall presence of the type 3 fimbria is uncommon (5.94–7.37%), although genes encoding the structure were detected in representatives of the five E. hormaechei subspecies. Exploration of complete genomes indicates that, in most of the cases, the mrkABCDF locus, encoding the type 3 fimbria, is located in plasmids. Furthermore, sequence types currently found in healthcare-associated infections were found to harbor genes encoding the type 3 fimbria, mainly ST145, ST78, ST118, ST168, ST66, ST93, and ST171. Thus, although the type 3 fimbria is not widespread among the species, it might be a determinant of fitness for a subset of E. hormaechei representatives. [ABSTRACT FROM AUTHOR]

Coffee leaf rust, caused by the fungus Hemileia vastatrix , has become a major concern for coffee-producing countries. Additionally, there has been an increase in the resistance of certain races of the fungus to fungicides and breeding cultivars, making producers use alternative control methods. In this work, we transplanted the leaf surface microbiota of rust-resistant coffee species (Coffea racemosa and Coffea stenophylla) to Coffea arabica and tested whether the new microbiota would be able to minimize the damage caused by H. vastatrix. It was seen that the transplant was successful in controlling rust, especially from C. stenophylla , but the protection depended on the concentration of the microbiota. Certain fungi, such as Acrocalymma, Bipolaris, Didymella, Nigrospora, Setophaeosphaeria, Simplicillium, Stagonospora and Torula , and bacteria, such as Chryseobacterium, Sphingobium and especially Enterobacter , had their populations increased and this may be related to the antagonism seen against H. vastatrix. Interestingly, the relative population of bacteria from genera Pantoea, Methylobacterium and Sphingomonas decreased after transplantation, suggesting a positive interaction between them and H. vastatrix development. Our findings may help to better understand the role of the microbiota in coffee leaf rust, as well as help to optimize the development of biocontrol agents. [ABSTRACT FROM AUTHOR]

Due to the high microbiological contamination of raw food materials and the increase in the incidence of multidrug-resistant bacteria, new methods of ensuring microbiological food safety are being sought. One solution may be to use bacteriophages (so-called phages) as natural bacterial enemies. Therefore, the aim of this study was the biological and genomic characterization of three newly isolated Serratia- and Enterobacter-specific virulent bacteriophages as potential candidates for food biocontrol. Serratia phage KKP_3708 (vB_Sli-IAFB_3708), Serratia phage KKP_3709 (vB_Sma-IAFB_3709), and Enterobacter phage KKP_3711 (vB_Ecl-IAFB_3711) were isolated from municipal sewage against Serratia liquefaciens strain KKP 3654, Serratia marcescens strain KKP 3687, and Enterobacter cloacae strain KKP 3684, respectively. The effect of phage addition at different multiplicity of infection (MOI) rates on the growth kinetics of the bacterial hosts was determined using a Bioscreen C Pro growth analyzer. The phages retained high activity in a wide temperature range (from −20 °C to 60 °C) and active acidity values (pH from 3 to 12). Based on transmission electron microscopy (TEM) imaging and whole-genome sequencing (WGS), the isolated bacteriophages belong to the tailed bacteriophages from the Caudoviricetes class. Genomic analysis revealed that the phages have linear double-stranded DNA of size 40,461 bp (Serratia phage KKP_3708), 67,890 bp (Serratia phage KKP_3709), and 113,711 bp (Enterobacter phage KKP_3711). No virulence, toxins, or antibiotic resistance genes were detected in the phage genomes. The lack of lysogenic markers indicates that all three bacteriophages may be potential candidates for food biocontrol. [ABSTRACT FROM AUTHOR]

Background: Currently, the Enterobacteriaceae species are responsible for a variety of serious infections and are already considered a global public health problem, especially in underdeveloped countries, where surveillance and monitoring programs are still scarce and limited. Analyses were performed on the complete genome of an extensively antibiotic-resistant strain of Enterobater hormaechei, which was isolated from a patient with non-Hodgkin's lymphoma, who had been admitted to a hospital in the city of Manaus, Brazil. Methods: Phenotypical identification and susceptibility tests were performed in automated equipment. Total DNA extraction was performed using the PureLink genomic DNA mini-Kit. The genomic DNA library was prepared with Illumina Microbial Amplicon Prep and sequenced in the MiSeq Illumina Platform. The assembly of the whole-genome and individual analyses of specific resistance genes extracted were carried out using online tools and the Geneious Prime software. Results: The analyses identified an extensively resistant ST90 clone of E. hormaechei carrying different genes, including blaCTX-M-15, blaGES-2, blaTEM-1A, blaACT-15, blaOXA-1 and blaNDM-1, [aac(3)-IIa, aac(6′)-Ian, ant(2″)-Ia], [aac(6′)-Ib-cr, (qnrB1)], dfrA25, sul1 and sul2, catB3, fosA, and qnrB, in addition to resistance to chlorhexidine, which is widely used in patient antisepsis. Conclusions: These findings highlight the need for actions to control and monitor these pathogens in the hospital environment. [ABSTRACT FROM AUTHOR]

Here, we report the comprehensive genome analysis of Enterobacter cloacae SBP-8 and its pan-genome comparison to other Enterobacter species. Genome comparison was performed by the BioRing Image Generator Tool, which predicted its genome similarity to other closest strains. Detailed annotations of the genome revealed different families of carbohydrate-degrading enzymes (CAZymes) that might be involved in the degradation of decaying plant materials with industrial significance for biomass research and the food industry. Moreover, the microbial secretome contains a number of proteins that generally interact with other microbes, environmental space, and the host. The secretion of proteins is performed by the secretory system present in the bacterial cell, however, only a few secretome proteins have been studied in limited bacterial strains. Therefore, we explored the secretome analysis of E. cloacae SBP-8 by nano LC-MS/MS and identified 776 proteins that provide insight into the role of these proteins in bacterial adaptation to different environments. The secretome proteins were classified into molecular, biological, and cellular functions using Blast2GO, whereas the subcellular localization was predicted by the PSORB tool. Many of the secretome proteins belonged to virulence proteins including Type VI secretion system (T6SS) proteins, chemotaxis & fimbriae formation proteins, outer membrane proteins (OMPs), and exotoxin secretion. Moreover, STRING analysis showed the interaction among the identified proteins. The detailed investigations of secretome proteins may provide an understanding of the possible pathogenicity of test organism E. cloacae SBP-8, and is also clinically important for the development of biomarkers and therapeutic approaches. [ABSTRACT FROM AUTHOR]

Plant biostimulants have received attention as sustainable alternatives to chemical fertilizers. Extracellular polymeric substances (EPSs), among the compounds secreted by plant growth-promoting rhizobacteria (PGPRs), are assumed to alleviate abiotic stress. This study aims to investigate the effect of purified EPSs on rice under abiotic stress and analyze their mechanisms. A pot experiment was conducted to elucidate the effects of inoculating EPSs purified from PGPRs that increase biofilm production in the presence of sugar on rice growth in heat-stress conditions. Since all EPSs showed improvement in SPAD after the stress, Enterobacter ludwigii, which was not characterized as showing higher PGP bioactivities such as phytohormone production, nitrogen fixation, and phosphorus solubilization, was selected for further analysis. RNA extracted from the embryos of germinating seeds at 24 h post-treatment with EPSs or water was used for transcriptome analysis. The RNA-seq analysis revealed 215 differentially expressed genes (DEGs) identified in rice seeds, including 139 up-regulated and 76 down-regulated genes. A gene ontology (GO) enrichment analysis showed that the enriched GO terms are mainly associated with the ROS scavenging processes, detoxification pathways, and response to oxidative stress. For example, the expression of the gene encoding OsAAO5, which is known to function in detoxifying oxidative stress, was two times increased by EPS treatment. Moreover, EPS application improved SPAD and dry weights of shoot and root by 90%, 14%, and 27%, respectively, under drought stress and increased SPAD by 59% under salt stress. It indicates that bacterial EPSs improved plant growth under abiotic stresses. Based on our results, we consider that EPSs purified from Enterobacter ludwigii can be used to develop biostimulants for rice. [ABSTRACT FROM AUTHOR]

Selenium (Se) is an essential trace element for human physiological metabolism. The application of organic Se as a source to cultivate Se-rich plants for micronutrient supplementation has been receiving increasing attention. In our study, a bacterial strain named H1 was isolated from the soil in Heilongjiang Province, China, and under optimal culture conditions, the unit Se content could reach 3000 μg·g−1 and its 16S ribosomal DNA sequence seemed to be a new molecular record of an Enterobacter species. After the domestication of Se tolerance and Se-rich experiments, H1 can be used as a Se source for cultivation of Se-rich Auricularia auricula. The results showed that soluble protein, soluble sugar, free amino acid and vitamin C contents in Auricularia auricula were notably increased by 28.7%, 21.8%, 32.5% and 39.2% under the treatment of Se concentration of 0.24 mg·kg−1, respectively. These findings enhance our understanding that H1 is more conducive to Se uptake and nutrient accumulation. [ABSTRACT FROM AUTHOR]

Background: Acidic environments naturally occur worldwide and uncontrolled use of agricultural practices may also cause acidification of soils. The development of acidic conditions disturbs the establishment of efficient microbial populations in their natural niches. The survival of Enterobacter species under acidic stress remains poorly understood. Objective: This study aimed to investigate the survival of an environmental isolate Enterobacter sp. S-33 under acidic stress and to identify the various genes involved in stress protection at the global gene transcription level. The obtained results provide new targets that will allow understanding the in-depth mechanisms involved in the adaptation of bacteria to environmental pH changes. Methods: We used the next-generation sequencing (NGS) method to analyze the expression (up-regulation & down-regulation) of genes under varying pH conditions. Results: A total of 4214 genes were differentially expressed under acidic conditions (pH 5.0), with 294 up-regulated and 167 down-regulated. At pH 6.0, 50 genes were significantly expressed, of which 34 and 16 were identified as up-regulated and down-regulated, respectively. Many of the up-regulated genes were involved in carbohydrate metabolism, amino acid transport & metabolism, and the most down-regulated genes were related to post-translational modification, lipid transport & metabolism, etc. The observed transcriptomic regulation of genes and pathways identified that Enterobacter reduced its post-translational modification, lipid transport & metabolism, and increased carbohydrate metabolism, amino acid metabolism & transport, energy production & conversion to adapt and grow in acidic stress. Conclusions: The present work provides in-depth information on the characterization of genes associated with tolerance or adaptation to acidic stress of Enterobacter bacterium. [ABSTRACT FROM AUTHOR]

In this study, we describe an Enterobacter ludwigii clinical isolate that is resistant to both carbapenems and colistin in South Korea. Antimicrobial susceptibility testing revealed that E. ludwigii CRE2104-31 was non-susceptible to all tested antibiotics except fosfomycin. Whole genome sequencing identified a 323-kbp IncHI2 plasmid, pCRE2104-31a, that was co-harbouring mobile colistin resistance (mcr)-9.1 and blaIMP-1. In comparison with other full plasmids, pCRE2104-31a exhibited the closest similarity to a plasmid from the Klebsiella pneumoniae strain CNR48 from France, with 19.9% query coverage and 99% identity. Notably, we observed five tandem repeats of blaIMP-1 and aac(6′)-Il genes, accompanied by multiple attCs within a class I integron on the Tn402-like transposon. The unit of blaIMP-1-attC-aac(6′)-Il-attC might have accumulated due to multiple convergent events. In addition to mcr-9.1 and blaIMP-1, various other antibiotic resistance-associated genes were identified in the plasmid, as follows: blaTEM-1B, aph(3′)-I, aph(3′)-Ia, aac(6′)-Il, aac(6′)-IIc, aac(6′)-IIa, aph(6)-Id, aph(3′')-Ib, aadA2b, aac(6′)-Ib3, sul, dfrA19, qnrB2, aac(6′)-Ib-cr, ere(A), and qacE. A conjugation assay showed that the mcr-9.1/blaIMP-1-co-bearing plasmid was self-transmissible to E. coli J53. However, colistin and carbapenem resistance could not be transferred to E. coli due to high incompatibility. The convergence of mcr and carbapenemase genes is thought to be host-dependent among Enterobacteriaceae. The emergence of extensively drug-resistant E. ludwigii co-harbouring MCR-9.1 and a multicopy of blaIMP-1 would pose a significant threat within the compatible Enterobacteriaceae.

Background: The biosynthesis of zinc oxide nanoparticles (ZnO NPs) using Enterobacter sp. and the evaluation of their antimicrobial and copper stress (Cu+ 2)-reducing capabilities in Vicia faba (L.) plants. The green-synthesized ZnO NPs were validated using X-ray powder diffraction (XRD); Fourier transformed infrared (FTIR), Ultraviolet-Visible spectroscopy (UV-Vis), Transmission electron microscope (TEM) and scanning electron microscopy (SEM) techniques. ZnO NPs could serve as an improved bactericidal agent for various biological applications. as well as these nanoparticles used in alleviating the hazardous effects of copper stress on the morphological and physiological traits of 21-day-old Vicia faba (L.) plants. Results: The results revealed that different concentrations of ZnO NPs (250, 500, or 1000 mg L-1) significantly alleviated the toxic effects of copper stress (100 mM CuSO4) and increased the growth parameters, photosynthetic efficiency (Fv/Fm), and pigments (Chlorophyll a and b) contents in Cu-stressed Vicia faba (L.) seedlings. Furthermore, applying high concentration of ZnO NPs (1000 mg L-1) was the best dose in maintaining the levels of antioxidant enzymes (CAT, SOD, and POX), total soluble carbohydrates, total soluble proteins, phenolic and flavonoid in all Cu-stressed Vicia faba (L.) seedlings. Additionally, contents of Malondialdehyde (MDA) and hydrogen peroxide (H2O2) were significantly suppressed in response to high concentrations of ZnO NPs (1000 mg L-1) in all Cu-stressed Vicia faba (L.) seedlings. Also, it demonstrates strong antibacterial action (0.9 mg/ml) against various pathogenic microorganisms. Conclusions: The ZnO NPs produced in this study demonstrated the potential to enhance plant detoxification and tolerance mechanisms, enabling plants to better cope with environmental stress. Furthermore, these nanoparticles could serve as an improved bactericidal agent for various biological applications. [ABSTRACT FROM AUTHOR]

This study aimed to isolate and comprehensively characterize chitinase-producing bacterial isolates collected from diverse aquatic stations in the Red Sea. Out of twenty nine isolates, chitinase-producing marine Enterococcus hirae (OR064172) and Enterococcus faecalis (OR053873) were biochemically and genetically identified. The two isolates have primary specific activity of 10.7 and 11.5U/ mg for E. hirae and E. faecalis, respectively. To enhance the purity of the chitinase enzymes, ammonium sulfate precipitation was employed, yielding 12.9 and 13.47U/ mg for 70% fractions of E. hirae and E. faecalis, respectively. Afterward, DEAEcellulose chromatography was utilized for the purification process, resulting in two peaks for E. hirae and one peak for E. faecalis. The results of chitinase characterization indicated optimal conditions with a temperature of 37°C, a pH of 6.5, and a salt tolerance of up to 1% for both strains. The indepth kinetic chitinase analysis unveiled the optimum Km (0.03 and 0.07) and Vmax (0.124 and 0.0003) conditions for chitinase activity for both E. hirae and E. faecalis, respectively. The application of the previous strains at the economic level involves the production of chitinase using marine shrimp waste in an attempt to extract beneficial products. The solid state fermentation process of this waste for both isolates was also tested, with results indicating that the specific activity of the produced enzyme was 8.48 and 11.38U/ mg, respectively, achieving the highest production after 48 hours. This study adeptly accomplished the isolation and identification of chitinase-producing marine bacterial isolates. The rigorous purification and comprehensive characterization of chitinase enzymes offer valuable insights into their production, refinement, and utilization across diverse industries, particularly within aquaculture and waste management. [ABSTRACT FROM AUTHOR]

The Enterobacter cancerogenus strain EcHa1 was isolated from the dead larvae of Helicoverpa armigera, and has the potential for biocontrol of some Lepidoptera insects. In order to screen insecticidal-related genes by qRT-PCR, stable endogenous reference genes used for normalizing qRT-PCR data were selected and evaluated from 13 housekeeping genes (HKGs). The expression levels of the HKGs were determined using qRT-PCR under different experimental conditions, including two culture temperatures and three bacterial OD values. Five stability analysis methods (Ct, BestKeeper, NormFinder, geNorm, and RefFinder) were used to comprehensively rank the candidate genes. The results showed that the optimal reference genes varied under different experimental conditions. The combination of gyrA and gyrB was recommended as the best reference gene combination at 28 °C, while gyrA and rpoB was the best combination at 37 °C. When the OD values were 0.5, 1.0 and 2.0, the recommended reference gene combinations were ftsZ and gyrA, rpoB and gyrB, and gyrA and pyk, respectively. The most suitable reference genes were gyrA and gyrB under all experimental conditions. Using gyrA and gyrB as the reference genes for qRT-PCR, EcHa1 was found to invade all tissues of the H. armigera larvae, and expressed a candidate pathogenic factor Hcp at high levels in gut, Malpighian tubules, and epidermis tissues. This study not only establishes an accurate and reliable normalization for qRT-PCR in entomopathogenic bacteria but also lays a solid foundation for further study of functional genes in E. cancerogenus. [ABSTRACT FROM AUTHOR]

Chromium is a prevalent toxic heavy metal, and chromate [Cr(VI)] exhibits high mutagenicity and carcinogenicity. The presence of the Cr(VI) efflux protein ChrA has been identified in strains exhibiting resistance to Cr(VI). Nevertheless, certain strains of bacteria that are resistant to Cr(VI) lack the presence of ChrB, a known regulatory factor. Here, a PadR family transcriptional repressor, ChrN, has been identified as a regulator in the response of Enterobacter sp. Z1(CCTCC NO: M 2019147) to Cr(VI). The chrN gene is cotranscribed with the chrA gene, and the transcriptional expression of this operon is induced by Cr(VI). The binding capacity of the ChrN protein to Cr(VI) was demonstrated by both the tryptophan fluorescence assay and Ni-NTA purification assay. The interaction between ChrN and the chrAN operon promoter was validated by reporter gene assay and electrophoretic mobility shift assay. Mutation of the conserved histidine residues His14 and His50 resulted in loss of ChrN binding with the promoter of the chrAN operon. This observation implies that these residues are crucial for establishing a DNA-binding site. These findings demonstrate that ChrN functions as a transcriptional repressor, modulating the cellular response of strain Z1 to Cr(VI) exposure. [ABSTRACT FROM AUTHOR]

Carbapenemase-producing Enterobacter spp. Serratia marcescens, Citrobacter freundii, Providencia spp., and Morganella morganii (CP-ESCPM) are increasingly identified as causative agents of nosocomial infections but are still not under systematic genomic surveillance. In this study, using a combination of whole-genome sequencing and conjugation experiments, we sought to elucidate the genomic characteristics and transferability of resistance genes in clinical CP-ESCPM isolates from Bulgaria. Among the 36 sequenced isolates, NDM-1 (12/36), VIM-4 (11/36), VIM-86 (8/36), and OXA-48 (7/36) carbapenemases were identified; two isolates carried both NDM-1 and VIM-86. The majority of carbapenemase genes were found on self-conjugative plasmids. IncL plasmids were responsible for the spread of OXA-48 among E. hormaechei, C. freundii, and S. marcescens. IncM2 plasmids were generally associated with the spread of NDM-1 in C. freundii and S. marcescens, and also of VIM-4 in C. freundii. IncC plasmids were involved in the spread of the recently described VIM-86 in P. stuartii isolates. IncC plasmids carrying blaNDM-1 and blaVIM-86 were observed too. blaNDM-1 was also detected on IncX3 in S. marcescens and on IncT plasmid in M. morganii. The significant resistance transfer rates we observed highlight the role of the ESCPM group as a reservoir of resistance determinants and stress the need for strengthening infection control measures. [ABSTRACT FROM AUTHOR]

Tomato is perishable and requires preservation to extend its shelf life. In this study, we conducted selection processes to identify essential oils that can help to avoid spoilage and deterioration during tomato storage and extend the shelf life. Thereafter, we determined the phosphatase activity assay, potassium ion concentration, and electron microscopy to study the antibacterial mechanism of essential oil. We found that Enterobacter ludwigii W01 was the dominant spoilage bacterium in tomatoes with cracked and curled skin. We selected oregano essential oil from 12 essential oils (oregano essential oil, lemon essential oil, osmanthus essential oil, cypress wood essential oil, tea tree essential oil, licorice essential oil, Baili essential oil, white camphor essential oil, Shancang seed essential oil, rosemary essential oil, rose essential oil, and cinnamon essential oil) which could significantly inhibit the activity of E. ludwigii W01. However, the diameter of the inhibition zone for Wh, Te, Cy, Li, Rm, Le, and Os is 0 mm, the diameter of the inhibition zone for Ba, Sh, and Ro was less than 1.0 mm, whereas the diameter of the inhibition zone for Ci and Or was greater than 2.0 mm. The diameter of the suppression circle for Ci and Or was greater than 2.0 mm, while Ci was lesser than Or. Oregano essential oil can damage the cell wall of E. ludwigii W01, leading to the leakage of the alkaline phosphatase stored between the cell wall and the cell membrane which can increase the alkaline phosphatase activity in the bacterial solution. Meanwhile, the addition of oregano essential oil significantly altered the cellular morphology of E. ludwigii W01. Spraying the surface of fresh tomato fruits with 1 MIC (0.125%) of oregano essential oil prolonged the storage time to 15 days, without significant changes in its sensory attributes. Those results indicated that oregano essential oil was a potential preservative for tomatoes. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance poses a global threat to human health. Analyzing monitoring data on antimicrobial resistance can assist clinicians in making strategic decisions and promptly identifying outbreaks of antimicrobial-resistant organisms. The China Antimicrobial Surveillance Network (CHINET) was established in 2004 to monitor the trends in bacterial epidemiology and antimicrobial resistance. In this study, we analyzed the distribution and changing antimicrobial resistance profiles of Enterobacter spp. isolated from 53 hospitals across China between 2015 and 2021 using the CHINET data. Over the seven-year period, a total of 37,966 clinical isolates of Enterobacter spp. were obtained, accounted for 2.5% of all isolates and 5.7% of Enterobacteriaceae isolates. Among those isolates, Enterobacter cloacae was the most prevalent, comprising 93.7% (35,571/37,966). The majority of strains were isolated from respiratory tract samples (44.6%), followed by secretion, pus (16.4%), and urine samples (16.0%). As for patient composition, 37,966 Enterobacter spp. strains were predominantly isolated from inpatients (92.9%), whereas 7.1% were isolated from outpatients and emergency patients. Among inpatients, isolates from patients in surgical ward accounted for the highest percentage (24.4%). E. cloacae exhibited the lowest rates of resistance to amikacin, tigecycline, polymyxin B, imipenem, and meropenem (resistance rates < 8%). However, the percentage of carbapenem-resistant Enterobacter spp. was 10.0%, presenting a rising tendency over the 7-year study period. Antimicrobial resistance profiles of Enterobacter spp. isolates varied according to the department of isolation and patient age (adult or child), with the intensive care unit having the highest proportion of carbapenem-resistant Enterobacter spp. isolates. [ABSTRACT FROM AUTHOR]

The rhizobacterium Enterobacter sp. DBA51 (DBA51), isolated from the semi-desert in Coahuila, Mexico, was previously found to increase the vegetative growth of tomato and tobacco plants cultivated under greenhouse conditions. The present report describes the results obtained from two independent open-field experiments performed with tomato and jalapeño pepper commercial crops inoculated with DBA51. Additionally, plants inoculated with Bacillus subtilis LPM1 (LPM1) and uninoculated plants were included as positive and negative controls, respectively. DBA51 and LPM1 significantly promoted growth at vegetative stages in the tomato plants; this effect was evident in the stem diameter (DBA51 with p < 0.0001 and LPM1 with p < 0.0001) and height (DBA51 with p < 0.0001 and LPM1 with p < 0.0001) of the tomato plants. However, no differences were detected in the jalapeño pepper plants. Additionally, DBA51 and LPM1 treatments increased tomato fruit production by 80% and 31%, respectively, compared to uninoculated plants. A similar increase in yield was recorded in DBA51- and LPM1-treated jalapeño pepper plants, which was 75% and 56% higher than uninoculated controls, respectively. These results strongly recommend the potential use of DBA51 as a biofertilizer in horticultural crops. [ABSTRACT FROM AUTHOR]

Simple Summary: Bacterial symbionts, especially Wolbachia, are vital in many physiological processes of insects. However, the mean infection prevalence of Wolbachia in many species of lepidopteran insects is relatively low. Here, we investigated the infection, composition, abundance, and diversity of bacterial symbionts, especially Wolbachia, associated with Spodoptera frugiperda. Our results revealed that Wolbachia was found in the ovaries and salivary glands of S. frugiperda female adults. Although the infection and abundance of Wolbachia varied between geographical populations, they all belonged to the supergroup B and were named the wFru strain, which has been considered to potentially induce cytoplasmic incompatibility. These findings may provide a foundation for developing potential biocontrol techniques for S. frugiperda. Bacterial symbionts associated with insects can be crucial in insect nutrition, metabolism, immune responses, development, and reproduction. However, the bacterial symbionts of the fall armyworm Spodoptera frugiperda remain unclear. S. frugiperda is an invasive polyphagous pest that severely damages many crops, particularly maize and wheat. Here, we investigated the infection, composition, abundance, and diversity of bacterial symbionts, especially Wolbachia, in different tissues of S. frugiperda female adults. The infection prevalence frequencies of Wolbachia in five provinces of China, namely Pu'er, Yunnan; Nanning, Guangxi; Sanya, Hainan; Yunfu, Guangdong; and Nanping, Fujian, were assessed. The results indicated that Proteobacteria, Firmicutes, and Bacteroidetes were the three most dominant bacterial phyla in S. frugiperda adults. At the genus level, the abundant microbiota, which included Enterobacter and Enterococcus, varied in abundance between tissues of S. frugiperda. Wolbachia was found in the ovaries and salivary glands of S. frugiperda adults, and was present in 33.33% of the Pu'er, Yunnan, 23.33% of the Nanning, Guangxi, and 13.33% of the Sanya, Hainan populations, but Wolbachia was absent in the Yunfu, Guangdong and Nanping, Fujian populations. Further phylogenetic analyses revealed that all of the Wolbachia strains from the different S. frugiperda populations belonged to the supergroup B and were named the wFru strain. Since there were Wolbachia strains inducing cytoplasmic incompatibility in supergroup B, these findings may provide a foundation for developing potential biocontrol techniques against S. frugiperda. [ABSTRACT FROM AUTHOR]

Bacterial microbiota are involved in tick physiology and varies with various factors. The variation of bacterial microbiota among tick organs is less investigated. In this study, the bacterial microbiota of four organs (ovaries, salivary glands, midgut, and Malpighian tubules) from the engorged female Haemaphysalis longicornis were surveyed using 16S rRNA high-throughput sequencing. Results indicated that the bacterial richness and diversity varied among tick organs, and ovaries had the lowest level of bacterial richness and diversity. The ovaries and salivary glands had relatively stable bacterial compositions when considering bacterial abundance. Proteobacteria was the dominant bacterial phylum in the four organs, followed by Firmicutes, Bacteroidota and Actinobacteriota. The ovaries carried more Proteobacteria, while the Firmicutes abundance was higher in salivary glands. The environmental bacteria including Staphylococcus, Pseudomonas, Brevundimonas, Acinetobacter, Enterobacter, and Stenotrophomonas had high abundance in the midgut and salivary glands, suggesting that ticks can acquire environmental bacteria through blood meals or host skin. The predominant proportion of Coxiella in ovaries ensures its vertical transmission, and Coxiella in Malpighian tubules can provide nutrients to the host. In conclusion, organ-specific bacterial microbiota was observed in the engorged female H. longicornis, and the functions of these bacteria in organs remain to be investigated. [ABSTRACT FROM AUTHOR]

Urinary tract infections are one of the most common infections affecting outpatients and hospital patients. They are believed to affect 150 million people annually and can present as an asymptomatic infection or infections of varying course and location. Patients most often present with symptoms of dysuria or increased frequency of urination. Urinary tract infections can be divided into lower and upper urinary tract infections, and the most common aetiological agents are Enterobacterales bacilli such as: Escherichia coli, Proteus spp., Klebsiella spp., Enterobacter spp., and Gram-positive cocci Enterococcus spp., Streptococcus agalactiae, and Staphylococcus saphrophyticus. Urinary tract diseases are a major public health burden, and significantly affect the quality of life of affected individuals. The choice of antibiotic and dosage should take into account the patient's health status, the effectiveness of the drug, along with its side effects. [ABSTRACT FROM AUTHOR]

Pollution of the Lagos Lagoon is one of the major ecological concerns in Lagos metropolis. The ecological survey of coliform was performed to determine the level of pollution in Lagos Lagoon. Water samples were collected from Iddo, Makoko, Unilag, Oyingbo, and Marina sample stations. The physicochemical and bacteriological analyses were performed under standard procedures. The values of the water samples ranged from; 4.2±0.019 to 7.7±0.016 for pH; 26.7 ±0.012 to 28.9±0.125 for temperature (°C); 0.38±0.016 to 0.56±0.044 for turbidity (nephelometric turbidity unit (NTU)) and 541.8±13.207 to 40672.02±1252.930 for salinity(mg/L). The selected physicochemical parameter results were analyzed using the one-way ANOVA test. The test revealed that the mean values of the parameters were not significantly different for the five sample stations. The pairwise test revealed no significant difference between the sample stations in the Lagos Lagoon. The predominant bacteria isolated belonged to the following genera: Klebsiella, Escherichia, Providencia, Salmonellae, Enterobacter, Aeromonas, Pseudomonas, and Citrobacter. The total viable counts ranged from 1.0 x 107 cfu/mL to 2.5 x 109 cfu/mL, and the total coliform counts ranged from 1.0 x 105 cfu/mL to 2.5 x 106 cfu/mL. The study revealed high coliform count in Lagos Lagoon. Therefore, the study stresses the need for authorities to implement laws and regulations to prohibit the discharge of untreated wastes into waterbodies to control faecal pollution. [ABSTRACT FROM AUTHOR]

The increasing world population needs a standard balanced diet to address malnutrition problems. For this purpose, seed priming is one of the best techniques, which helps to increase the production of functional and nutritional food crops. Different techniques have been used for seed priming, but biological priming is the most frequently used because biocontrol agents offer a friendly environment for the growth of food crops. In this study, Momordica charantia L. seeds were subjected to a strain of Enterobacter sp. FD17 as a biocontrol agent at different time exposures (i.e., 24 h, 48 h, and 72 h). Leaf growth, flavonoids, chlorophyll content, amino acids, soluble sugars, protein, and total soluble phenolics were studied in the vegetative stage. The yield of nutritive components was evaluated from fruit, peel, and pulp of M. charantia. Biopriming was revealed to improve the final emergence rate, mean emergence time, seedling vigor, emergence index, and vigor indices I and II. Among the growth parameters, the root (0.45 ± 0.045 g) and shoot fresh weight (1.23 ± 0.05 g), leaf area (15.52 ± 1.5 cm), shoot length (30.33 ± 0.58 cm), number of flowers (6 ± 1.0), fruit weight (96.33 ± 1.15 g), and germination percentage (56.67 ± 11.55%) were also improved. Among biochemical analyses, biopriming improved chlorophyll a (6.33 ± 0.58 mg/g) and b (8.58 ± 2.5 mg/g), total soluble sugar (33.13 ± 2.24%), and total chlorophyll content (9.0 ± 1.5 mg/g). The nutritional analysis showed that free amino acids (1.43 ± 0.02 mg/g), total soluble sugar (42.53 ± 1.65%), ash (20.53 ± 2.57%), and catalase (347.47 ± 34.76 U/g) were increased in fruit, while crude fiber (3.62 ± 0.1%) and peroxidase (5.61 ± 0.34 U/g) in peel and protein and metabolizable energy in peel and fruit were increased. Among the water, acetone, and methanol extracts, the maximum antibacterial activity was shown by methanol extracts of leaves against Gram-negative and Gram-positive bacterial species (i.e., Pseudomonas aeruginosa and Staphylococcus aureus, respectively) with inhibitory diameters of 3 mm. Biopriming also improved the phenolic contents in the leaves and fruits of M. charantia. Biopriming treatment was also revealed to be directly correlated with antiglycation activity. Therefore, biopriming treatment on seeds could be used to manipulate plant cell metabolism with a substantial improvement in phenolic content, antibacterial activity, and growth of M. charantia. [ABSTRACT FROM AUTHOR]

Carbapenems are last-resort antibiotics used to treat multidrug-resistant bacterial infections. Resistance to carbapenems has been designated as an urgent threat and is increasing in healthcare settings. However, little is still known about the distribution and characteristics of carbapenem-resistant bacteria (CRB) outside of healthcare settings. Here, we surveyed the distribution of CRB in ten diverse freshwater and seawater environments in California, U.S., ranging from San Luis Obispo County to San Bernardino County, combining both direct isolation and enrichment approaches to increase the diversity of isolated CRB. From the locations surveyed, we selected 30 CRB for further characterization. These isolates were identified as members of the genera Aeromonas, Enterobacter, Enterococcus, Paenibacillus, Pseudomonas, Sphingobacterium, and Stenotrophomonas. These isolates were resistant to carbapenems, other β-lactams, and often to other antibiotics (tetracycline, gentamicin, or ciprofloxacin). We also found that nine isolates belonging to the genera Aeromonas, Enterobacter (blaIMI-2), and Stenotrophomonas (blaL1) produced carbapenemases. Overall, our findings indicate that sampling different types of aquatic environments and combining different isolation approaches increase the diversity of the environmental CRB obtained. Moreover, our study supports the increasingly recognized role of natural water systems as an underappreciated reservoir of bacteria resistant to carbapenems and other antibiotics, including bacteria carrying carbapenemase genes. [ABSTRACT FROM AUTHOR]

2-Phenylethanol (2-PE) and indole-3-acetic acid (IAA) are important secondary metabolites produced by microorganisms, and their production are closely linked to the growth state of microorganisms and environmental factors. Enterobacter CGMCC 5087 can produce both 2-PE and IAA depending on α-ketoacid decarboxylase KDC4427. This study aimed to investigate the effects of different environment factors including osmotic pressure, temperature, and pH on the synthesis of 2-PE and IAA in Enterobacter sp. CGMCC 5087. The bacteria exhibited an enhanced capacity for 2-PE synthesis while not affecting IAA synthesis under 5% NaCl and pH 4.5 stress conditions. In an environment with pH 9.5, the synthesis capacity of 2-PE remained unchanged while the synthesis capacity of IAA decreased. The synthesis ability of 2-PE was enhanced with an increase in temperature within the range of 25 °C to 37 °C, while the synthesis capacity of IAA was not affected significantly. Additionally, the expression of KDC4427 varied under stress conditions. Under 5% NaCl stress and decreased temperature, expression of the KDC4427 gene was increased. However, altering pH did not result in significant differences in gene expression levels, while elevated temperature caused a decrease in gene expression. Furthermore, molecular docking and molecular dynamics simulations suggested that these conditions may induce fluctuation in the geometry shape of binding cavity, binding energy, and especially the dαC-C- value, which played key roles in affecting the enzyme activity. These results provide insights and strategies for the synthesis of metabolic products 2-PE and IAA in bacterial fermentation, even under unfavorable conditions. [ABSTRACT FROM AUTHOR]

Background: The International Space Station (ISS) stands as a testament to human achievement in space exploration. Despite its highly controlled environment, characterised by microgravity, increased CO 2 levels, and elevated solar radiation, microorganisms occupy a unique niche. These microbial inhabitants play a significant role in influencing the health and well-being of astronauts on board. One microorganism of particular interest in our study is Enterobacter bugandensis, primarily found in clinical specimens including the human gastrointestinal tract, and also reported to possess pathogenic traits, leading to a plethora of infections. Results: Distinct from their Earth counterparts, ISS E. bugandensis strains have exhibited resistance mechanisms that categorise them within the ESKAPE pathogen group, a collection of pathogens recognised for their formidable resistance to antimicrobial treatments. During the 2-year Microbial Tracking 1 mission, 13 strains of multidrug-resistant E. bugandensis were isolated from various locations within the ISS. We have carried out a comprehensive study to understand the genomic intricacies of ISS-derived E. bugandensis in comparison to terrestrial strains, with a keen focus on those associated with clinical infections. We unravel the evolutionary trajectories of pivotal genes, especially those contributing to functional adaptations and potential antimicrobial resistance. A hypothesis central to our study was that the singular nature of the stresses of the space environment, distinct from any on Earth, could be driving these genomic adaptations. Extending our investigation, we meticulously mapped the prevalence and distribution of E. bugandensis across the ISS over time. This temporal analysis provided insights into the persistence, succession, and potential patterns of colonisation of E. bugandensis in space. Furthermore, by leveraging advanced analytical techniques, including metabolic modelling, we delved into the coexisting microbial communities alongside E. bugandensis in the ISS across multiple missions and spatial locations. This exploration revealed intricate microbial interactions, offering a window into the microbial ecosystem dynamics within the ISS. Conclusions: Our comprehensive analysis illuminated not only the ways these interactions sculpt microbial diversity but also the factors that might contribute to the potential dominance and succession of E. bugandensis within the ISS environment. The implications of these findings are twofold. Firstly, they shed light on microbial behaviour, adaptation, and evolution in extreme, isolated environments. Secondly, they underscore the need for robust preventive measures, ensuring the health and safety of astronauts by mitigating risks associated with potential pathogenic threats. DtSaop7bYTNkSCdR7trwLe Video Abstract [ABSTRACT FROM AUTHOR]