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A number of insects are associated with gut symbiotic microorganisms, wherein symbiotic partners play pivotal metabolic roles for each other such as nutrient supplementation, diet degradation, and pesticide detoxification. Despite the ecological and evolutionary importance of gut microbial communities in insects, their diversity and dynamics remain unclear in many species. The green plant bug Apolygus spinolae, a notorious grapevine pest in Japan, damages grape shoots and severely reduces grape berry yield and quality. The plant bug possesses a simple tubular gut housing ~ 104 bacteria. Here, we investigated geographic, seasonal, and growth-related dynamics of gut microbiota by high-throughput sequencing in 82 individuals (11 nymphs and 71 adults) from five locations in Hokkaido, Japan. In plant bugs, gut microbiota changed dynamically depending on region, season, and developmental stage. Among the gut bacteria, Serratia was consistently and abundantly detected and was significantly affected by seasonal changes. In addition, Caballeronia, known as a specific symbiont in some stinkbug species, was abundantly detected, especially in insects collected in late summer despite A. spinolae complete lack of midgut crypts known as symbiotic organ harboring Caballeronia in other stinkbug species. Considering their prevalence among host bug populations, it is possible these gut microorganisms play a pivotal role in the adaptation of the green plant bug to grapevine fields, although further confirmation through rearing experiments is needed. [ABSTRACT FROM AUTHOR]

Serratia plymuthica UBCF_13 produces the maximum level of indole-3-acetic acid (IAA) in yeast mannitol medium. However, the impact of medium ingredients on gene expression and metabolites related to IAA synthesis remains unclear. Therefore, Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) was used to assess the effects of culture medium optimization components on the genes involved in IAA production. High-Performance Liquid Chromatography (HPLC) has been employed to investigate the impact of medium constituents on the metabolites associated with the biosynthesis of IAA. The highest IAA production was found in sucrose and yeast extract as the carbon and nitrogen sources (134.6 µg/mL). It was also discovered that calcium carbonate and magnesium sulfate are significant inorganic salts for UBCF_13 in the production of IAA. Most genes showed higher levels of expression when sucrose was used as the carbon source, including ipdC, nthA, puuC, amiE, oxdA, tyrB and nthB. Furthermore, the expression of tyrB, puuC, DDC and oxdA was upregulated in response to calcium carbonate, while puuC, nthA, nthB and amiE expression levels were elevated in the presence of magnesium sulfate. Indole-3-acetamide (IAM) was identified with HPLC as an intermediate product in several optimized culture media, with the highest IAA concentration (429.79 µg/mL) which was observed in yeast sucrose medium. Thus, sucrose played a pivotal role in IAA biosynthesis, and yeast sucrose medium supplemented with complete inorganic salts emerged as the optimal medium for IAA production by UBCF_13. [ABSTRACT FROM AUTHOR]

Background: Endometrial hyperplasia (EH) is a precursor to endometrial cancer, and the role of the microbiome in its development is unclear. Results: The present study investigated the uterine microbiome in patients with benign uterine conditions and endometrial hyperplasia. A significant structural shift in the uterine microbiome of patients with endometrial hyperplasia compared to those with benign conditions was found. Delftia, Serratia and Stenotrophomonas were significantly enriched in endometrial hyperplasia samples and associated with the presence of endometrial hyperplasia. Conclusions: The novel finding suggested that increased abundance of Delftia, Serratia and Stenotrophomonas is associated with the presence of endometrial hyperplasia. Further investigation is needed to determine the value of these microbes as biomarkers for endometrial hyperplasia. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to evaluate the antibiotic resistance of microorganisms isolated in cases of culture-positive nosocomial late-onset neonatal sepsis in the neonatal intensive care unit. Materials and Methods: Infants admitted to our neonatal intensive care unit between October 2015 and June 2022 were retrospectively screened. A total of 458 different cultures from 386 sepsis incidents in 250 infants were analyzed. Results: Over an 8-year period, 407 cases of culture-positive nosocomial late-onset neonatal sepsis were reviewed in a total of 4244 infants. Twenty-one cases were excluded due to insufficient data. The incidence of culture-positive nosocomial sepsis was 6.3%. Coagulase-negative Staphylococcus and Staphylococcus aureus were the most common gram-positive bacteria found in cultures. Resistance to ampicillin and cephalosporin treatments was high, while resistance to vancomycin, teicoplanin, and linezolid was low. Klebsiella spp. were the most frequent gram-negative bacteria isolated in cultures and showed high resistance to non-carbapenembased regimens. The only fungal microorganisms isolated in cultures were Candida spp., which had a high mortality rate despite their low resistance profile. The mortality rate due to nosocomial sepsis was 19.6%. Conclusion: Our study demonstrated that microorganisms and their antibiotic resistance profiles changed over time in the newborn intensive care unit. Gram-negative pathogens exhibited high antibiotic resistance, while fungi had high mortality rates. It is essential to adjust empirical antibiotic regimens for nosocomial sepsis based on thorough surveillance. [ABSTRACT FROM AUTHOR]

Insect’s gut microbiota has diverse effects on their fitness, and a comprehensive understanding of gut microbiota functions requires analyzing its diversity. Apolygus lucorum is a highly destructive pest that threatens many economically important crops in China. This study investigated the gut microbiota of A. lucorum across its life cycle using both culture-dependent and culture-independent methods. A total of 87 gut bacterial isolates were identified, belonging to 4 phyla, 27 families, and 45 genera, while Miseq sequencing detected 91 amplicon sequence variants (ASVs) assigned to 5 phyla, 28 families, and 39 genera. Proteobacteria and Firmicutes were the predominant phyla, with Staphylococcus and Serratia as the major genera. There were significant differences in the relative abundance of these genera between the nymph and adult stages. Staphylococcus was significantly more abundant in nymphs than it in adults, while Serratia was significantly more abundant in sexually mature adults than in other developmental stages. Notably, Serratia is a common opportunistic pathogen in many insects. Injecting the gut-dominant isolate Serratia marcescens verified its high pathogenicity. Additionally, immune indicators of the bug at different developmental stages supported the hypothesis that Serratia is a pathogen of A. lucorum. This study provides a foundation for understanding the role of gut bacteria in the life history of A. lucorum and developing new pest control strategies based on microbes. [ABSTRACT FROM AUTHOR]

Introduction: Urinary tract infection (UTI) is the most common infection of the pediatric age group. Several factors linked to higher prevalence include poor personal hygiene, improper sanitation, lower socioeconomic status, and malnourishment. In addition to having a worse quality of life, the 1.8 million children who live in Karachi's Korangi district are routinely exposed to such factors. Objectives: The study aims to evaluate the frequency of UTI and distribution of uropathogens along with their antimicrobial susceptibility pattern in patients presenting to a pediatric tertiary care center in the Korangi district of Karachi, Pakistan. Design: The study employed an observational cross-sectional design. Methods: The study was conducted at the Microbiology laboratory of Sindh Institute of Child Health and Neonatology, Karachi, Pakistan from 1st January to 15th August 2023. Urine samples of patients 1 to 16 years of age were collected via midstream clean catch method and of patients from birth up to 1 year were collected in urine collection bags. The samples were cultured on Cystine Lactose Electrolyte Deficient (CLED) agar and antibiotic susceptibility testing was performed using the Kirby-Bauer Disc Diffusion method. Results: A total of 457 urine samples were collected, of which 90 (19.7%) were positive for significant uropathogens. With a mean age of 4.6 years, majority of the culture-positive patients were female (n = 72; 80%). Enterobacterales were the most frequently isolated (n = 88; 95.6%), of which Escherichia coli was the most common (73.9%; n = 68). Citrobacter (n = 7; 7.6%), Klebsiella (n = 6; 6.5%), Serratia (n = 4; 4.3%), Proteus (n = 2; 2.2%), Salmonella (n = 2; 2.2%), and Enterobacter (n = 1; 1.1%) were among the other Enterobacterales isolated. Meropenem and imipenem were the most effective in isolates from Enterobacterales (n = 88) followed by amikacin (n = 84), ciprofloxacin (n = 75), and piperacillin-tazobactam (n = 70). Ceftriaxone and cefixime exhibited moderate susceptibility (n = 69 and 52) whereas, amoxicillin-clavulanate was the least susceptible (n = 3). Conclusion: We report high frequency of UTI in our pediatric population with uropathogens and associated antimicrobial susceptibility pattern confirming to the existing trends of pediatric UTIs in Pakistan. In addition to valuable insights for treating patients under similar conditions, our study serves as a catalyst for further multi-center research in this area. [ABSTRACT FROM AUTHOR]

The NG-Test CARBA 5 and Carbapenem-resistant K.N.I.V.O. Detection K-Set are lateral flow assays (LFAs) that rapidly detect five carbapenemases (KPC, NDM, IMP, VIM and OXA-48-like). We evaluated the effect of inoculum size on the performance of these two assays using 27 Enterobacterales isolates. Whole-genome sequencing (WGS) was used as the reference method. Using the NG-Test CARBA 5, eight Serratia spp. and six M. morganii isolates showed false-positive NDM results with a high inoculum. Using the Carbapenem-resistant K.N.I.V.O. Detection K-Set, eight M. morganii, four Serratia spp. and one K. pneumoniae isolates showed false-positive NDM and/or OXA-48-like bands at large inoculum sizes, while the other two M. morganii isolates demonstrated false-positive NDM and OXA-48-like results at all inoculum sizes. The false-positive bands varied in intensity. WGS confirmed that no carbapenemase gene was present. No protein sequence with a ≥50% identity to NDM or OXA-48-like enzymes was found. This study emphasizes the importance of assessing inoculum size in the diagnostic evaluation of LFAs. [ABSTRACT FROM AUTHOR]

The contemporary food industry's uses of nanoemulsions (NEs) include food processing, effective nutraceutical delivery, the development of functional chemicals, and the synthesis of natural preservatives, such as phytocompounds. Although cinnamon essential oil (CEO) is widely used in the cosmetic, pharmaceutical, and food industries, it is difficult to add to aqueous‐based food formulations due to its weak stability and poor water solubility. This study describes the formulation of a CEO nanoemulsion (CEONE) by spontaneous emulsification and evaluates its antibacterial and antibiofilm properties against biofilm‐forming Serratia rubidaea BFMO8 isolated from spoiled emperor fish (Lethrinus miniatus). Bacteria causing spoilage in emperor fish were isolated and identified as S. rubidaea using common morphological, cultural, and 16S RNA sequencing methods, and their ability to form biofilms and their susceptibility to CEONE were assessed using biofilm‐specific methods. The spontaneous emulsification formulation of CEONE was accomplished using water and Tween 20 surfactant by manipulating organic and aqueous phase interface properties and controlling particle growth by capping surfactant increases. The best emulsification, with highly stable nano‐size droplets, was accomplished at 750 rpm and a 1:3 ratio concentration. The stable CEONE droplet size, polydispersity index, and zeta potential values were 204.8 nm, 0.115, and −6.05 mV, respectively. FTIR and high‐resolution liquid chromatography‐mass spectrometry (HR‐LCMS) analyses have revealed carboxyl, carbonyl, and phenol‐like primary phytochemical functional groups in CEO and CEONE, which contribute to their antibacterial and antibiofilm properties. [ABSTRACT FROM AUTHOR]

Serratia are opportunistic bacteria, causing infections in plants, insects, animals and humans under certain conditions. The development of bacterial infection in the human body involves several stages of host–pathogen interaction, including entry into non-phagocytic cells to evade host immune cells. The facultative pathogen Serratia proteamaculans is capable of penetrating eukaryotic cells. These bacteria synthesize an actin-specific metalloprotease named protealysin. After transformation with a plasmid carrying the protealysin gene, noninvasive E. coli penetrate eukaryotic cells. This suggests that protealysin may play a key role in S. proteamaculans invasion. This review addresses the mechanisms underlying protealysin's involvement in bacterial invasion, highlighting the main findings as follows. Protealysin can be delivered into the eukaryotic cell by the type VI secretion system and/or by bacterial outer membrane vesicles. By cleaving actin in the host cell, protealysin can mediate the reversible actin rearrangements required for bacterial invasion. However, inactivation of the protealysin gene leads to an increase, rather than decrease, in the intensity of S. proteamaculans invasion. This indicates the presence of virulence factors among bacterial protealysin substrates. Indeed, protealysin cleaves the virulence factors, including the bacterial surface protein OmpX. OmpX increases the expression of the EGFR and β1 integrin, which are involved in S. proteamaculans invasion. It has been shown that an increase in the invasion of genetically modified S. proteamaculans may be the result of the accumulation of full-length OmpX on the bacterial surface, which is not cleaved by protealysin. Thus, the intensity of the S. proteamaculans invasion is determined by the balance between the active protealysin and its substrate OmpX. [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: Lignin is an intricate phenolic polymer found in plant cell walls that has tremendous potential for being converted into value-added products with the possibility of significantly increasing the economics of bio-refineries. Although lignin in nature is bio-degradable, its biocatalytic conversion is challenging due to its stable complex structure and recalcitrance. In this context, an understanding of strain's genomics, enzymes, and degradation pathways can provide a solution for breaking down lignin to unlock the full potential of lignin as a dominant valuable bioresource. A gammaproteobacterial strain AORB19 has been isolated previously from decomposed wood based on its high laccase production. This work then focused on the detailed genomic and functional characterization of this strain based on whole genome sequencing, the identification of lignin degradation products, and the strain's laccase production capabilities on various agro-industrial residues. Results: Lignin degrading bacterial strain AORB19 was identified as Serratia quinivorans based on whole genome sequencing and core genome phylogeny. The strain comprised a total of 123 annotated CAZyme genes, including ten cellulases, four hemicellulases, five predicted carbohydrate esterase genes, and eight lignin-degrading enzyme genes. Strain AORB19 was also found to possess genes associated with metabolic pathways such as the β-ketoadipate, gentisate, anthranilate, homogentisic, and phenylacetate CoA pathways. LC–UV analysis demonstrated the presence of p-hydroxybenzaldehyde and vanillin in the culture media which constitutes potent biosignatures indicating the strain's capability to degrade lignin. Finally, the study evaluated the laccase production of Serratia AORB19 grown with various industrial raw materials, with the highest activity detected on flax seed meal (257.71 U/L), followed by pea hull (230.11 U/L), canola meal (209.56 U/L), okara (187.67 U/L), and barley malt sprouts (169.27 U/L). Conclusions: The whole genome analysis of Serratia quinivorans AORB19, elucidated a repertoire of genes, pathways and enzymes vital for lignin degradation that widens the understanding of ligninolytic metabolism among bacterial lignin degraders. The LC-UV analysis of the lignin degradation products coupled with the ability of S. quinivorans AORB19 to produce laccase on diverse agro-industrial residues underscores its versatility and its potential to contribute to the economic viability of bio-refineries. [ABSTRACT FROM AUTHOR]

Tomatoes are frequently challenged by various pathogens, among which Phytophthora capsici (P. capsici) is a destructive soil‐borne pathogen that seriously threatens the safe production of tomatoes. Plant growth‐promoting rhizobacteria (PGPR) positively induced plant resistance against multiple pathogens. However, little is known about the role and regulatory mechanism of PGPR in tomato resistance to P. capsici. Here, we identified a new strain Serratia plymuthica (S. plymuthica), HK9‐3, which has a significant antibacterial effect on P. capsici infection. Meanwhile, stable colonization in roots by HK9‐3, even under P. capsici infection, improved tomato growth parameters, root system architecture, photosynthetic capacity, and boosted biomass. Importantly, HK9‐3 colonization significantly alleviated the damage caused by P. capsici infection through enhancing ROS scavenger ability and inducing antioxidant defense system and pathogenesis‐related (PR) proteins in leaves, as evidenced by elevating the activities of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), and chitinase, β‐1,3‐glucanase, and increasing the transcripts of POD, SOD, CAT, APX1, PAL1, PAL2, PAL5, PPO2, CHI17 and β‐1,3‐glucanase genes. Notably, HK9‐3 colonization not only effectively improved soil microecology and soil fertility, but also significantly enhanced fruit yield by 44.6% and improved quality. Our study presents HK9‐3 as a promising and effective solution for controlling P. capsici infection in tomato cultivation while simultaneously promoting plant growth and increasing yield, which may have implications for P. capsici control in vegetable production. [ABSTRACT FROM AUTHOR]

The biosyntheses of sodorifien and chlororaphen demonstrate impressively that in bacteria an additional way of terpene biosynthesis was established which results in the production of new – so far unknown – natural terpene products. For these biosynthetic pathways, especially the properties of two specialized enzymes are responsible. This is on the one hand a bifunctional SAM-dependent FPP-methyltransferase with cyclase activity and on the other hand a terpene synthase with altered substrate specificity. Thus, it has been documented that – deviating from the C5 unit-depending isoprene rule – there is another possibility of modifying classical prenyl pyrophosphates to C16 or C17 cyclized substrates. Subsequently, the 136-year-old isoprene dogma has to be expanded or modified. [ABSTRACT FROM AUTHOR]

Diseases that occur in silkworms include soft rot, hardening disease, digestive diseases, and sepsis. However, research on the causes of bacterial diseases occurring in silkworms and the resulting changes in the microbial community is lacking. Therefore, we examined the morphological characteristics of sepsis and changes in the microbial community between silkworms that exhibit a unique odor and healthy silkworms; thus, we established a relationship between disease-causing microorganisms and sepsis. After producing a 16S rRNA amplicon library for samples showing sepsis, we obtained information on the microbial community present in silkworms using next-generation sequencing. Compared to that in healthy silkworms, in silkworms with sepsis, the abundance of the Firmicutes phylum was significantly reduced, while that of Proteobacteria was increased. Serratia sp. was dominant in silkworms with sepsis. After bacterial isolation, identification, and reinfection through the oral cavity, we confirmed this organism as the disease-causing agent; its mortality rate was 1.8 times higher than that caused by Serratia marcescens. In summary, we identified a new causative bacterium of silkworm sepsis through microbial community analysis and confirmed that the microbial community balance was disrupted by the aberrant proliferation of certain bacteria. [ABSTRACT FROM AUTHOR]

A bacterial strain 22S belonging to the genus Serratia was isolated from soil samples contaminated with chemical production wastes. The strain was found to be nonpathogenic based on the study of its virulence, toxicity, infectivity, and invasiveness. In batch culture, Serratia sp. 22S was able to separately utilize chlorophenoxyacetic acids (100 mg/L) as the sole source of carbon and energy. The catabolism pathway for chlorophenoxyacetic acids was suggested through complete reductive dechlorination of the substrate followed by meta-cleavage of the aromatic ring of catechol based on the compounds found in the culture medium (2,4-dichloro-6-methylphenoxyacetic, phenoxyacetic, and 2-hydroxy-2-hexenedionic acids). Intact cells experiments confirmed this assumption. In model systems, good adaptability and survival of the 22S strain in the soil was revealed, and the content of chlorophenoxyacetic acids up to a certain concentrations had a positive effect on the growth of the strain, most likely due to its selective effect. [ABSTRACT FROM AUTHOR]

Donated human milk is the best possible alternative when mother's own milk is not available. The aim of this study is to investigate whether there are differences in the milk donation volumes and microbiological quality of donated milk depending on human milk donors (HMDs) characteristics. We analyzed data on the HMDs who donated milk in the first three years of work of human milk bank (HMB) – November 2019 to January 2023. The data on the volume of donated milk in L and suitable microbiological quality assessed by the number and isolated species of bacteria were collected from questionnaires filled out by HMDs and documentation administered by HMB employees and are presented using descriptive and comparative statistics. Two hundred HMDs were included in this study. The majority of them are between 26 and 35 years of age, reside in capital city or the surrounding county, have given birth to a full-term child vaginally, and express surplus milk through a breast pump. Donor mothers of preterm born infants (14.5 %) donated greater quantities, there is statistically significant difference in the median of volume of milk donated (9.6 vs. 6.4, p=0.026). Milk expressed manually shows better results in microbiological quality (median percentage 100 vs. 82 vs. 100, p=0.040), while by comparing other characteristics of the donors, no difference was found between the groups. It is important to be aware of the characteristics of previous HMDs in order to direct the HMB future promotional and educational activities. [ABSTRACT FROM AUTHOR]

Background: The viability and persistence of engineered bacterium candidates in field conditions is one of the considerable challenges in the paratransgenesis approach to fighting vector-borne diseases. Methods: In this study two engineered bacterium candidates to produce paratransgenic sand flies, Serratia AS1 and Enterobacter cloacae expressing m-Cherry fluorescent were applied on the leaves of the white saxaul plant (Haloxylon persicum), sugar bait, and rodent burrow soil and their persistent time was tested in desert condition, Matin Abad County, Isfahan, August 2022. A PBS suspension of 109 cells/ml was used for sugar bait, spraying on plant leaves (~10 cm2 ) and 10 cm2 of rodent burrow soil. Sand fly samples were taken daily and were plated on LB Agar and the fluorescent cells were counted after 24 hours. Results: Time course in general caused a decrease in the number of bacteria for both strains. The two strains were persistent in sugar bait and on plant leaves for four days and on soil for two days. Although there were slight differences between the number of the bacteria in sugar baits, which was not significant (P< 0.05). The number of E. cloacae surviving on plant and in soil were significantly (P< 0.0001 and P= 0.046) higher than Serratia AS1. Conclusion: This study shows that plants or sugar bait are useful routes for delivery of the transformed bacteria for the paratransgenesis approach, although, the bacteria ought to be sprayed on plants or sugar baits should be replaced with new ones in four days intervals. [ABSTRACT FROM AUTHOR]

This report describes the clinical presentation and progression of a Serratia marcescens‐associated subcutaneous abscess in a dog with hypothyroidism, hyperadrenocorticism and diabetes mellitus. The S. marcescens isolate was resistant to several antibiotics. Treatment with antibiotics and topical antiseptics was not successful. [ABSTRACT FROM AUTHOR]

Hypsizygus marmoreus has become one of the most popular edible mushrooms due to its high nutritional and economic value. Previous researchers found that Serratia odorifera could promote the growth of H. marmoreus by producing and secreting some of its inducers. However, the specific mechanism of action was still unclear. In this study, we found that the exogenous addition of sterile fermentation filtrate (HZSO-1), quorum sensing (QS) signaling molecules, 3-oxo-C6-HSL, cyclo(Pro-Leu), and cyclo(Tyr-Leu) could significantly promote the growth of H. marmoreus, increase the number of clamp junctions, and the diameter of mycelium (p < 0.05). In addition, non-targeted metabolomic analysis revealed that 706 metabolites were detected in the treated group. Of these, 307 metabolites were significantly different (p < 0.05). Compared with the control, 54 and 86 metabolites were significantly increased and decreased in the HZSO-1 group, respectively (p < 0.05). We speculate that the sterile fermentation filtrate of S. odorifera could mediate the carbohydrate and amino acid metabolism of H. marmoreus by influencing the pentose phosphate pathway (PPP) to increase the energy supply for the growth and development of the mycelium. The above results will further reveal the growth-promoting mechanism of S. odorifera on H. marmoreus. [ABSTRACT FROM AUTHOR]

Bacteria use cell surface proteins to mediate host–pathogen interactions. Proteins responsible for cell adhesion, including E-cadherin, serve as receptors for entry into the host cell. We have previously shown that an increase in eukaryotic cell sensitivity to Serratia grimesii correlates with an increase in E-cadherin expression. On the other hand, Serratia proteamaculans invasion involves the EGFR, which can interact with E-cadherin on the surface of host cells. Therefore, we investigated the role of E-cadherin in Serratia invasion into M-HeLa and Caco-2 cells. Bacterial infection increased E-cadherin expression in both cell lines. Moreover, E-cadherin was detected in the Caco-2 cells in a full-length form and in the M-HeLa cells in only a truncated form in response to incubation with bacteria. Transfection with siRNA targeting E-cadherin inhibited S. proteamaculans invasion only into the Caco-2 cells. Thus, only full-length E-cadherin is involved in S. proteamaculans invasion. On the other hand, transfection with siRNA targeting E-cadherin inhibited S. grimesii invasion into both cell lines. Thus, not only may full-length E-cadherin but also truncated E-cadherin be involved in S. grimesii invasion. Truncated E-cadherin can be formed as a result of cleavage by bacterial proteases or the Ca2+-activated cellular protease ADAM10. The rate of Ca2+ accumulation in the host cells depends on the number of bacteria per cell upon infection. During incubation, Ca2+ accumulates only when more than 500 S. grimesii bacteria are infected per eukaryotic cell, and only under these conditions does the ADAM10 inhibitor reduce the sensitivity of the cells to bacteria. An EGFR inhibitor has the same quantitative effect on S. grimesii invasion. Apparently, as a result of infection with S. grimesii, Ca2+ accumulates in the host cells and may activate the ADAM10 sheddase, which can promote invasion by cleaving E-cadherin and, as a result, triggering EGFR signaling. Thus, the invasion of S. proteamaculans can only be promoted by full-length E-cadherin, and S. grimesii invasion can be promoted by both full-length and truncated E-cadherin. [ABSTRACT FROM AUTHOR]

Most insects harbour influential, yet non‐essential heritable microbes in their hemocoel. Communities of these symbionts exhibit low diversity. But their frequent multi‐species nature raises intriguing questions on roles for symbiont–symbiont synergies in host adaptation, and on the stability of the symbiont communities, themselves. In this study, we build on knowledge of species‐defined symbiont community structure across US populations of the pea aphid, Acyrthosiphon pisum. Through extensive symbiont genotyping, we show that pea aphids' microbiomes can be more precisely defined at the symbiont strain level, with strain variability shaping five out of nine previously reported co‐infection trends. Field data provide a mixture of evidence for synergistic fitness effects and symbiont hitchhiking, revealing causes and consequences of these co‐infection trends. To test whether within‐host metabolic interactions predict common versus rare strain‐defined communities, we leveraged the high relatedness of our dominant, community‐defined symbiont strains vs. 12 pea aphid‐derived Gammaproteobacteria with sequenced genomes. Genomic inference, using metabolic complementarity indices, revealed high potential for cooperation among one pair of symbionts—Serratia symbiotica and Rickettsiella viridis. Applying the expansion network algorithm, through additional use of pea aphid and obligate Buchnera symbiont genomes, Serratia and Rickettsiella emerged as the only symbiont community requiring both parties to expand holobiont metabolism. Through their joint expansion of the biotin biosynthesis pathway, these symbionts may span missing gaps, creating a multi‐party mutualism within their nutrient‐limited, phloem‐feeding hosts. Recent, complementary gene inactivation, within the biotin pathways of Serratia and Rickettsiella, raises further questions on the origins of mutualisms and host–symbiont interdependencies. [ABSTRACT FROM AUTHOR]

Introduction: Bacteremia caused by Serratia rubidaea is seldom mentioned in comparison with other Enterobacteriaceae species. It primarily affects immunocompromised patients undergoing invasive procedures. Furthermore, the incidence, clinical features, and microbiological profile of this pathogen in the intensive care unit are rarely described. Case presentation: We present four North African case studies of bacteremia in four young female patients admitted to the intensive care unit for ketoacidosis with a history of diabetes mellitus. All four patients developed catheter-related infections complicated by deep vein thrombosis. The catheter site was femoral in all cases, and the main clinical manifestation was poorly tolerated fever. The pathogen was isolated in multiple peripheral blood cultures (> 4) for each patient, showing a similar profile in all cases: resistance to third-generation cephalosporins and sensitivity to aminoglycosides, piperacillin, fluoroquinolones, and folate-pathway inhibitors. Targeted treatment consisted of a combination of ciprofloxacin 400 mg twice per day and trimethoprim/sulfamethoxazole 400/80 mg thrice per day for all four cases. However, in one case, this regimen was switched to amikacin due to adverse effects. The outcomes were favorable in the majority of cases. The patients described in this study were 21, 66, 22, and 27-year-old North African women. Conclusion: Most of the reported cases shared common risk factors and clinical aspects. Notably, a case of thrombosis complicating a catheter infection caused by Serratia rubidaea has not been previously reported in the literature. Furthermore, this bloodstream infection typically affects deeply immunocompromised patients. However, our four cases, admitted to the intensive care unit for ketoacidosis, only had a history of diabetes mellitus. [ABSTRACT FROM AUTHOR]

The raising concern of drug resistance, having substantial impacts on public health, has instigated the search of new natural compounds with substantial medicinal activity. In order to find out a natural solution, the current study has utilized prodigiosin, a linear tripyrrole red pigment, as an active ingredient to control bacterial proliferation and prevent cellular oxidation caused by ROS (Reactive Oxygen Species). A prodigiosin-producing bacterium BRL41 was isolated from the ancient Barhind soil of BCSIR Rajshahi Laboratories, Bangladesh, and its morphological and biochemical characteristics were investigated. Whole genome sequencing data of the isolate revealed its identity as Serratia sp. and conferred the presence of prodigiosin gene cluster in the bacterial genome. "Prodigiosin NRPS", among the 10 analyzed gene clusters, showed 100% similarity with query sequences where pigC, pigH, pigI, and pigJ were identified as fundamental genes for prodigiosin biosynthesis. Some other prominent clusters for synthesis of ririwpeptides, yersinopine, trichrysobactin were also found in the chromosome of BRL41, whilst the rest displayed less similarity with query sequences. Except some first-generation beta-lactam resistance genes, no virulence and resistance genes were found in the genome of BRL41. Structural illumination of the extracted red pigment by spectrophotometric scanning, Thin-Layer Chromatography (TLC), Fourier Transform Infrared Spectroscopy (FTIR), and change of color at different pH solutions verified the identity of the isolated compound as prodigiosin. Serratia sp. BRL41 attained its maximum productivity 564.74 units/cell at temperature 30˚C and pH 7.5 in two-fold diluted nutrient broth medium. The compound exhibited promising antibacterial activity against Gram-positive and Gram-negative bacteria with MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) values ranged from 3.9 to15.62 μg/mL and 7.81 to 31.25 μg/mL respectively. At concentration 500 μg/mL, except in Salmonella enterica ATCC-10708, prodigiosin significantly diminished biofilm formed by Listeria monocytogens ATCC-3193, Pseudomonas aeruginosa ATCC-9027, Escherichia coli (environmental isolate), Staphylococcus aureus (environmental isolate). Cellular glutathione level (GSH) was elevated upon application of 250 and 500 μg/mL pigment where 125 μg/mL failed to show any free radical scavenging activity. Additionally, release of cellular components in growth media of both Gram-positive and Gram-negative bacteria were facilitated by the extract that might be associated with cell membrane destabilization. Therefore, the overall findings of antimicrobial, antibiofilm and antioxidant activities suggest that in time to come prodigiosin might be a potential natural source to treat various diseases and infections. [ABSTRACT FROM AUTHOR]

Horizontal transmission of bacteria to varied hosts can maintain and even expand microbial niches. We previously found that the aphid gut bacterium Serratia symbiotica strain SsMj can be transmitted to ladybird beetles via predation, but whether the predator is a new host, a reservoir or a dead end of this bacterium is unknown. This study aims to provide a clear picture of SsMj circulation from aphids to plants and predators. We first found that SsMj in aphids and ladybirds was abundantly distributed not only in digestive tracts but also in droppings. We found no evidence for vertical transmission of SsMj to aphid offspring. Instead, we showed that it could be transmitted to conspecific aphids by sharing the same plant or contacting honeydews. The key finding of this study is that SsMj was transmitted from aphids to ladybirds through predation, while ladybirds could also transfer SsMj back to aphids, possibly through feces. Together, this evidence suggests that SsMj is able to survive in the digestive tracts and droppings of insects and to expand its host range with plants and predators as reservoirs. [ABSTRACT FROM AUTHOR]

The present study assessed the occurrence of antibiotic-resistant Enterobacteriaceae in free-living White-eyed Parakeets (Psittacara leucophthalmus) inhabiting the metropolitan region of Sorocaba. For this purpose, cloacal swabs were collected from 30 parakeets, which were subsequently rescued and directed to the Municipal Zoo of the city. Bacterial culture of the biological samples on selective media and laboratory biochemical tests were conducted for the identification of Enterobacteriaceae. Escherichia coli was observed in 16 birds (53%), Edwardisiella tarda in three (10%), Serratia liquefaciens in two (6%), Citrobacter freundii in two (6%), Enterobacter cloacae in one (3%), and Serratia odorifera in only one bird (3%). Among the tested antibiotics, chloramphenicol exhibited the highest bacterial sensitivity, while aztreonam, cefepime, and ceftazidime showed no efficacy against any of the Enterobacteriaceae identified in the study. [ABSTRACT FROM AUTHOR]

There is increasing interest in the use of endosymbionts in pest control, which will benefit from the identification of endosymbionts from potential donor species for transfer to pest species. Here, we screened for endosymbionts in 123 Australian aphid samples across 32 species using 16S DNA metabarcoding. We then developed a qPCR method to validate the metabarcoding data set and to monitor endosymbiont persistence in aphid cultures. Pea aphids (Acyrthosiphon pisum) were frequently coinfected with Rickettsiella and Serratia, and glasshouse potato aphids (Aulacorthum solani) were coinfected with Regiella and Spiroplasma; other secondary endosymbionts detected in samples occurred by themselves. Hamiltonella, Rickettsia and Wolbachia were restricted to a single aphid species, whereas Regiella was found in multiple species. Rickettsiella, Hamiltonella and Serratia were stably maintained in laboratory cultures, although others were lost rapidly. The overall incidence of secondary endosymbionts in Australian samples tended to be lower than recorded from aphids overseas. These results indicate that aphid endosymbionts probably exhibit different levels of infectivity and vertical transmission efficiency across hosts, which may contribute to natural infection patterns. The rapid loss of some endosymbionts in cultures raises questions about factors that maintain them under field conditions, while endosymbionts that persisted in laboratory culture provide candidates for interspecific transfers. [ABSTRACT FROM AUTHOR]

Objectives The incidence of Serratia endocarditis is increasing, yet optimal treatment has not been defined. Our objective was to investigate the outcomes of patients with Serratia endocarditis by treatment strategy. Methods We reviewed adult patients with definitive Serratia endocarditis at two independent health systems between July 2001 and April 2023. Combination therapy was defined as receipt of ≥2 in vitro active agents for ≥72 h. Results Seventy-five patients were included; 64% (48/75) were male and 85% (64/75) were people who inject drugs. Compared with monotherapy, receipt of combination therapy was associated with lower rates of microbiological failure (0% versus 15%, P = 0.026) and 90 day all-cause mortality (11% versus 31%, P = 0.049). Antimicrobial discontinuation due to an adverse event was more common among patients receiving combination therapy compared with monotherapy (36% versus 8%, P = 0.058). Conclusions In the largest series of Serratia endocarditis to date, combination antibiotic treatment was associated with improved outcomes. However, larger, prospective studies are warranted. [ABSTRACT FROM AUTHOR]

Fusarium wilt, caused by Fusarium oxysporum f. sp. niveum (FON), is a predominant and devastating soil-borne disease that results in significant yield losses in watermelon cultivation. In this study, a strain MM isolated from the herbage rhizosphere soil, exhibited an inhibition rate of 65.46% against FON, leading to mycelial collapse, atrophy, and deformation. In pot experiments, strain MM effectively controlled Fusarium wilt of watermelon, showing a control efficacy of 74.07%. Through morphological observation and 16S rDNA gene sequencing, strain MM was identified as Serratia plymuthica. Additionally, S. plymuthica MM demonstrated antagonistic activity against eight plant pathogens, indicating that MM had broad-spectrum antifungal activity. The strain also exhibited the ability to synthesize siderophores and indole acetic acid (IAA), both of which are growth-promoting compounds. Moreover, strain MM secreted various extracellular enzymes, including protease, chitinase, β-glucanase, and cellulase. This ability allowed S. plymuthica MM to readily colonize watermelon roots and promote seedling growth. Inoculation with S. plymuthica MM increased the activity of PAL, POD, PPO, and CAT enzymes associated with watermelon defense. Furthermore, qRT-PCR analysis revealed up-regulation of LOX, POD, PAL, ClPR3, and C4H genes, which are related to plant disease resistance. The results indicated that S. plymuthica MM enhances watermelon plants' resistance to FON by activating the JA, SA, and shikimic acid phenylpropanoid–lignin synthesis pathways. Gas chromatography–mass spectrometry (GC-MS) analysis of S. plymuthica MM culture supernatant identified piperazinedione, pyrrolo[1,2-a]pyrazine-1,4-dione, and octadecenamide as the main antimicrobial substances. Overall, S. plymuthica MM shows promise as a biocontrol agent against Fusarium wilt of watermelon, suggesting its potential for the development of a new biocontrol agent. [ABSTRACT FROM AUTHOR]

Serratia marcescens is an opportunistic human pathogen involved in antibiotic-resistant hospital acquired infections. Upon contact with the host epithelial cell and prior to internalization, Serratia induces an early autophagic response that is entirely dependent on the ShlA toxin. Once Serratia invades the eukaryotic cell and multiples inside an intracellular vacuole, ShlA expression also promotes an exocytic event that allows bacterial egress from the host cell without compromising its integrity. Several toxins, including ShlA, were shown to induce ATP efflux from eukaryotic cells. Here, we demonstrate that ShlA triggered a nonlytic release of ATP from Chinese hamster ovary (CHO) cells. Enzymatic removal of accumulated extracellular ATP (eATP) or pharmacological blockage of the eATP-P2Y2 purinergic receptor inhibited the ShlA-promoted autophagic response in CHO cells. Despite the intrinsic ectoATPase activity of CHO cells, the effective concentration and kinetic profile of eATP was consistent with the established affinity of the P2Y2 receptor and the known kinetics of autophagy induction. Moreover, eATP removal or P2Y2 receptor inhibition also suppressed the ShlA-induced exocytic expulsion of the bacteria from the host cell. Blocking α5β1 integrin highly inhibited ShlA-dependent autophagy, a result consistent with α5β1 transactivation by the P2Y2 receptor. In sum, eATP operates as the key signaling molecule that allows the eukaryotic cell to detect the challenge imposed by the contact with the ShlA toxin. Stimulation of P2Y2-dependent pathways evokes the activation of a defensive response to counteract cell damage and promotes the nonlytic clearance of the pathogen from the infected cell. [ABSTRACT FROM AUTHOR]

Indole‐3‐acetic acid (IAA) is emerging as a key intra‐ and inter‐kingdom signal molecule that modulates a wide range of processes of importance during plant–microorganism interaction. However, the mechanisms by which IAA carries out its functions in bacteria as well as the regulatory processes by which bacteria modulate auxin production are largely unknown. Here, we found that IAA synthesis deficiency results in important global transcriptional changes in the broad‐range antibiotic‐producing rhizobacterium Serratia plymuthica A153. Most pronounced transcriptional changes were observed in various gene clusters for aromatic acid metabolism, including auxin catabolism. To delve into the corresponding molecular mechanisms, different regulatory proteins were biochemically characterized. Among them, a TyrR orthologue was essential for IAA production through the activation of the ipdc gene encoding a key enzyme for IAA biosynthesis. We showed that TyrR specifically recognizes different aromatic amino acids which, in turn, alters the interactions of TyrR with the ipdc promoter. Screening of mutants defective in various transcriptional and post‐transcriptional regulators allowed the identification of additional regulators of IAA production, including PigP and quorum sensing‐related genes. Advancing our knowledge on the mechanisms that control the IAA biosynthesis in beneficial phytobacteria is of biotechnological interest for improving agricultural productivity and sustainable agricultural development. [ABSTRACT FROM AUTHOR]

In this letter, we describe a patient who presented shortly after birth with recurrent infections, lymphocytosis, and congenital anomalies and was found to have a novel, private NF-kappa B Inhibitor Alpha ( I NFKBIA i ) variant, characterized in vitro to be a gain-of-function (GOF) allele. Yet, similar to previously reported patients with EDA-ID, we observed complications with HSCT including falling/mixed chimerism, and he eventually succumbed to his disease with infection causing worsening respiratory distress and parental desire for patient comfort. Complications from transplant were significant with over 50% of the 11 transplanted patients dying post-transplant, while four of the living transplanted patients remained on prophylaxis. (A) Time-course of TIL-1 -stimulated (right) SV40 fibroblasts from 2 controls, patient (NFKBIA D31N/WT), and NEMO deficient patient (NEMO-/-) with immunoblotting for phospho-IKK (p-IKK), IKK , p-I B , I B and GAPDH. [Extracted from the article]

Several studies have outlined that changes in the honeybee gut microbial composition may impair important metabolic functions supporting the honeybees' life. Gut dysbiosis may be caused by diseases like Nosema ceranae or by other anthropic, environmental or experimental stressors. The present work contributes to increasing knowledge on the dynamics of the gut microbiome acquisition in caged honeybees, an experimental condition frequently adopted by researchers, with or without infection with N. ceranae, and fed with a bacterial mixture to control N. ceranae development. Changes of the gut microbiota were elucidated comparing microbial profile of caged and open-field reared honeybees. The absolute abundance of the major gut microbial taxa was studied with both NGS and qPCR approaches, whereas changes in the functionality were based on RAST annotations and manually curated. In general, all caged honeybees showed important changes in the gut microbiota, with γ -proteobacteria (Frischella, Gilliamella and Snodgrassella) lacking in all caged experimental groups. Caged honeybees infected with N. ceranae showed also a strong colonization of environmental taxa like Citrobacter, Cosenzaea and Morganella, as well as possibly pathogenic bacteria such as Serratia. The colonization of Serratia did not occur in presence of the bacterial mixture. The functionality prediction revealed that environmental bacteria or the supplemented bacterial mixture increased the metabolic potential of the honeybee gut microbiome compared to field and caged controls. [ABSTRACT FROM AUTHOR]

Pathogenic fungi that cause defoliation in different pine species, including Pinus patula, have been reported. The most common practice for controlling these pathogens is the use of fungicides, which have adverse environmental consequences. The objective of this study was to evaluate an alternative for pathogen control without affecting the ecosystem. Bacteria with antifungal activity obtained from forest soil were isolated and biochemically and molecularly identified for evaluation in biocontrol assays of fungi associated with defoliation under laboratory and field conditions. Two species of the genus Serratia, Serratia grimesii and S. proteamaculans, were identified as bacteria with antifungal activity. In vitro biocontrol was achieved by reducing the mycelium growth of fungi associated with diseased needles of P. patula: Alternaria alternata, Annulohypoxylon stygium, Botryosphaeria dothidea, Curvularia lunata, C. pseudobrachyspora, C. spicifera, C. trifolii, Daldinia sp., Daldinia eschscholtzii, Diplodia sapinea, Lophodermium indianum, and Myrmaecium rubricosum. The fungi in P. patula (Annulohypoxylon stygium and Daldinia eschscholtzii) decreased their damage by 82% and 77%, respectively, in the presence of Serratia under humid chamber conditions. In addition, the incidence of lesions (IL) and Disease Severity Index (% D S I) were significantly reduced under natural conditions. The results showed that biocontrol with bacteria of the genus Serratia is an alternative for the management of health in Pinus patula trees. [ABSTRACT FROM AUTHOR]

Microbiota in the mosquito plays an important role in their behavior and vector competence. The composition of their microbiome is strongly influenced by the environment, especially their habitat. The microbiome profiles of adult female Anopheles sinensis mosquitoes from malaria hyperendemic and hypoendemic areas in Republic of Korea were compared using 16S rRNA Illumina sequencing. In different epidemiology groups, the alpha and beta diversity analyses were significant. The major bacterial phylum was Proteobacteria. The most abundant species in the microbiome of hyperendemic mosquitoes were the genera Staphylococcus, Erwinia, Serratia, and Pantoea. Notably, a distinct microbiome profile characterized by the dominance of Pseudomonas synxantha was identified in the hypoendemic area, suggesting a potential correlation between the microbiome profiles and the incidence of malaria cases. [ABSTRACT FROM AUTHOR]

Prolific contamination of low moisture foods by microorganisms poses a high public health risk for humans. The present study aimed at the microbiological analysis of a local Ready-to-Use Supplementary Food developed for treatment of malnourished children. Microbiological analysis included the determination of total viable aerobic count by standard plate count method, enumeration of total coliforms, yeasts and molds.The local Ready-to-Use Supplementary Food was developed at Chinhoyi University of Technology and analysed by conventional culture methods. Microorganisms were identified by VITEK 2system. Isolated microorganisms suspension inoculated into the VITEK 2 system. A total of 8 strains were investigated and 7 of these species (87.50%) were correctly identified while I strain (12.5%) was not identified. The correct identification rate ranged from 85% to 99%. Identified species were the 25% Enterobacter species,25%Bacillus species and 12.5% forPontea agglomerans, Serratia species, and Salinococcus roseus respectively. Average counts as log coli forming units per gram were total viable count 2.99, Staphylococcus aureus 1.23, total coliforms 1.3, and Enterobacteriaceae 1.15. Colony count quality was satisfactory according to the 2016 Irish Food Safety Authority guidelines. Total faecal coliforms, Escherichia coli, Salmonella, and Vibrio cholera were not detected. The results were satisfactory but the ready- to-supplementary food could pose a risk to humans due to presence of food borne pathogens and opportunistic bacteria. Relevant local authorities must ensure that hygienic conditions are improved to curb potential foodborne infections. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the impact of phosphorus deficiency in the interaction between the biofertilizer Serratia sp. S119 strain and peanut and maize plants. Plant assays were performed under P deficiency and several parameters of plant-bacterial interaction were measured. Bacterial chemotaxis, root colonization and biofilm production were measured as the first steps of the plant-bacteria interaction. Also, the effect of root exudates of plants grown in P deficiency on the ability to solubilize insoluble phosphate of Serratia sp. S119 was analyzed. Results were further correlated with analyzes of the pqqE gene expression and the measurement of the activity of pqq promoter. Finally, the effect of the root exudates on the ACC deaminase activity of S119 strain was measured. Results indicated that plant root exudates obtained under P-deficient conditions positively attract Serratia sp. S119 and stimulate its colonization and biofilm formation. These plant root compounds showed also to produce a stimulating effect of the phosphate solubilization ability and ACC deaminase activity of S119 strain. Finally, root exudates obtained under P-deficient conditions induce pqqE gene expression and the activity of pqq promoter of S119 strain. In conclusion, root exudates contain specific signal molecules that attract phosphate solubilizing bacteria to the rhizosphere of peanut and maize plants growing in P deficient condition. Signal molecules would favor the colonization and establishment of the PSB strain in the surface tissues as well as in inner tissues, stimulate phosphate solubilization ability and enhance ACC deaminase activity to decrease plant's nutritional stress response. [ABSTRACT FROM AUTHOR]

Background and Objectives: Biosurfactants are amphiphilic surface-active agents that mainly produced by various microorganisms. In this study, the anti-biofilm and inhibition of bacterial adhesion activities of two bacterial biosurfactants were investigated. Materials and Methods: After extraction and evaluation of Bacillus cereus and Serratia nematodiphila biosurfctants, inhibition of bacterial adhesion and anti-biofilm effects of them on Staphylococcus aureus and Pseudomonas aeruginosa were determined. Results: On average, the synergistic effect of two bacterial biosurfactants, caused about 60% decrease in adhesion and about 80% decrease in biofilm formation of S. aureus and P. aeruginosa. Conclusion: The results of this study showed that combination of B. cereus and S. nematodiphila biosurfactants would increase the potential of attachment inhibition and biofilm eradication with very low toxicity. [ABSTRACT FROM AUTHOR]

In order to reduce the use of chemical fertilizers, the use of biological inoculants has been increased. Beneficial microorganisms are used to increase crop yields by stimulating plant growth through the production of phytohormones. In the present study, Indole Acetic Acid (IAA) production was analyzed in 18 bacterial isolates with Plant Growth-Promoting (PGP) capabilities; 15 of these isolates were Rhizobium, and three were Serratia. All isolates have been characterized morphologically and biochemically, and their IAA production in the presence of tryptophan, a precursor for IAA biosynthesis, has been evaluated. IAA production was detected using the Salkowski reagent with CT-2200 spectrophotometer at 530 nm. The levels of IAA production varied between the different isolates. The top two IAA producers were selected for genetic identification using 16SrRNA primers (27F and 1492R). One of the Rhizobium isolates (NRC-R2) shared 95% sequence similarity with Rhizobium sp., according to a Blastn search in GenBank and Rhizobium leguminosarum, whereas the Serratia isolate (Ain Shams Center for Genetic Engineering and Biotechnology (ACGEB)-S2 was 99.5% similar to Serratia sp. In the near future, it is possible that these two isolates could serve as biological sources for IAA. [ABSTRACT FROM AUTHOR]

Cell membrane rafts form signaling platforms on the cell surface, controlling numerous protein–protein and lipid–protein interactions. Bacteria invading eukaryotic cells trigger cell signaling to induce their own uptake by non-phagocytic cells. The aim of this work was to reveal the involvement of membrane rafts in the penetration of the bacteria Serratia grimesii and Serratia proteamaculans into eukaryotic cells. Our results show that the disruption of membrane rafts by MβCD in the three cell lines tested, M-HeLa, MCF-7 and Caco-2, resulted in a time-dependent decrease in the intensity of Serratia invasion. MβCD treatment produced a more rapid effect on the bacterial susceptibility of M-HeLa cells compared to other cell lines. This effect correlated with a faster assembly of the actin cytoskeleton upon treatment with MβCD in M-HeLa cells in contrast to that in Caco-2 cells. Moreover, the 30 min treatment of Caco-2 cells with MβCD produced an increase in the intensity of S. proteamaculans invasion. This effect correlated with an increase in EGFR expression. Together with the evidence that EGFR is involved in S. proteamaculans invasion but not in S. grimesii invasion, these results led to the conclusion that an increase in EGFR amount on the plasma membrane with the undisassembled rafts of Caco-2 cells after 30 min of treatment with MβCD may increase the intensity of S. proteamaculans but not of S. grimesii invasion. Thus, the MβCD-dependent degradation of lipid rafts, which enhances actin polymerization and disrupts signaling pathways from receptors on the host cell's surface, reduces Serratia invasion. [ABSTRACT FROM AUTHOR]

The ability of a low-power ultrasound system to alter the physiology of cyanobacteria cells in controlled field applications was evaluated. Serratia sp., a model bacteria, and cyanobacteria collected from a bloom containing Microcystis sp. and Aphanizomenon sp., were placed in sound transparent containers and exposed to ultrasound in field studies. No observed changes in Serratia sp. and cyanobacteria gas vesicles between unexposed controls and ultrasound exposed samples were found. Cell viability and phycocyanin concentration for both model bacteria and environmental samples were not significantly affected. At the highest acoustic pressure measured (3.5 kPa), 1 m from the transducer, the acoustic pressures were over 100( lower than gas vesicle critical collapse pressures. Moreover, the ultrasound frequencies emitted are significantly lower than gas vesicle resonance frequencies. Therefore, consistent with pressure and frequency measurements, we found no evidence that gas vesicle collapse is the mechanism of ultrasound as a cyanobacteria mitigation strategy. [ABSTRACT FROM AUTHOR]

Simple Summary: Aphis gossypii Glover is an important agricultural pest distributed worldwide, which can reduce the yield of cotton crops and cause huge economic losses. Binodoxys communis Gahan is the main parasitoid wasp of A. gossypii. Previous studies have shown that parasitization causes reduced egg production in A. gossypii, but the effects on the symbiotic bacteria of the host ovaries are unknown. In this study, we analyzed the microbial communities in cotton aphid ovaries by 16S rDNA sequencing and their changes before and after parasitization, performed a functional prediction analysis of the microbial communities in cotton aphid ovaries, and finally performed RT-qPCR on some core symbiotic bacteria. In summary, our results provide a framework for investigating shifts in the microbial communities in host ovaries and broaden our understanding of the interactions among aphids, parasitoid wasps, and endosymbionts. Background: Aphis gossypii Glover is an important agricultural pest distributed worldwide. Binodoxys communis Gahan is the main parasitoid wasp of A. gossypii. Previous studies have shown that parasitization causes reduced egg production in A. gossypii, but the effects of parasitism on the symbiotic bacteria in the host ovaries are unknown. Results: In this study, we analyzed the microbial communities in the ovaries of A. gossypii without and after parasitization. Whether parasitized or not, Buchnera was the dominant genus of symbiotic bacteria in the ovaries, followed by facultative symbionts including Arsenophonus, Pseudomonas, and Acinetobacter. The relative abundance of Buchnera in the aphid ovary increased after parasitization for 1 d in both third-instar nymph and adult stages, but decreased after parasitization for 3 d. The shifts in the relative abundance of Arsenophonus in both stages were the same as those observed for Buchnera. In addition, the relative abundance of Serratia remarkably decreased after parasitization for 1 d and increased after parasitization for 3 d. A functional predictive analysis of the control and parasitized ovary microbiomes revealed that pathways primarily enriched in parasitization were "amino acid transport and metabolism" and "energy production and conversion." Finally, RT-qPCR analysis was performed on Buchnera, Arsenophonus, and Serratia. The results of RT-qPCR were the same as the results of 16S rDNA sequencing. Conclusions: These results provide a framework for investigating shifts in the microbial communities in host ovaries, which may be responsible for reduced egg production in aphids. These findings also broaden our understanding of the interactions among aphids, parasitoid wasps, and endosymbionts. [ABSTRACT FROM AUTHOR]

To describe clinico-microbiological features and outcomes of Serratia keratitis and to compare them with Pseudomonas aeruginosa keratitis. Cases of microbiologically proven Serratia keratitis and P. aeruginosa keratitis were reviewed. Data regarding demographic and clinical characteristics, and outcomes were recorded. 39 patients with pure Serratia keratitis were included. Median presenting vision was 1.8 logMAR (IQR, 0.8–2.4) and median infiltrate size was 5 mm (IQR 3–7.8 mm). An ocular risk factor was present in 35 (89.7%) cases. S. marcescens was the most common species (31/39, 79.5%). Medical resolution was observed in 36/39 (92.3%) cases, while three (7.7%) eyes needed penetrating keratoplasty. On comparing with P. aeruginosa keratitis (58 eyes), no difference in outcomes (p =.14) was noted. Serratia keratitis usually occurs in eyes with a compromised surface and has good resolution with medical therapy. Both Serratia and P. aeruginosa keratitis have similar outcomes. [ABSTRACT FROM AUTHOR]

Background: Serratia ureilytica DW2 is a highly efficient phosphate-solubilizing bacteria isolated from Codonopsis pilosula rhizosphere soil that can promote the growth of C. pilosula; nonetheless, until now, no validated reference genes from the genus Serratia have been reported that can be used for the normalization of quantitative real-time polymerase chain reaction (RT--qPCR) data. Methods: To screen stable reference genes of S. ureilytica DW2, the expression of its eight candidate reference genes (16S rRNA, ftsZ, ftsA, mreB, recA, slyD, thiC, and zipA) under different treatment conditions (pH, temperature, culture time, and salt content) was assayed by RT--qPCR. The expression stability of these genes was analyzed using different algorithms (geNorm, NormFinder, and BestKeeper). To verify the reliability of the data, the expression of the glucose dehydrogenase (gdh) gene under different soluble phosphate levels was quantified using the most stably expressed reference gene. Results: The results showed that the zipA and 16S rRNA genes were the most stable reference genes, and the least stable genes were thiC and recA. The expression of gdh was consistent with the phosphate solubilization ability on plates containing the National Botanical Research Institute phosphate growth medium. Conclusion: Therefore, this study provides a stable and reliable reference gene of Serratia for the accurate quantification of functional gene expression in future studies. [ABSTRACT FROM AUTHOR]

Background The objectives of this study were to describe the changing epidemiology of gram-negative infective endocarditis (GNIE) and to identify factors associated with treatment failure and death. Methods Adult patients with GNIE were included if they met modified Duke criteria for definitive infective endocarditis (IE) between April 2010 and December 2021. Patients were identified using Boolean search terms. Clinical failure was a defined as a composite of all-cause 42-day mortality or microbiologic failure. All analyses were performed using Stata, version 15.1. Results One-hundred twenty-three patients were included. The most common pathogens were Serratia spp. (43%), Pseudomonas aeruginosa (21%), and Klebsiella spp. (14%). Fifty-two percent of cases were among persons who injection drugs (PWID; n = 64), for whom Serratia spp. (70%) was the most common cause of GNIE. Overall, patients infected with P. aeruginosa had higher microbiologic failure rates than other patients (23% vs 6%; P =.004). Patients who received combination therapy (n = 53) had comparable median lengths of stay (23 vs 19.5 days; P =.412), microbiologic failure rates (11.3% vs 7.1%; P =.528), clinical failure rates (18.9% vs 22.9%; P =.592), and 90-day mortality rates (13.2% vs 25.7%; P =.088) as those treated with monotherapy. After applying stepwise logistic regression, male gender, Pitt Bacteremia Score, and not receiving surgical intervention despite a surgical indication were associated with clinical failure. Conclusions This is the first study to identify Serratia spp. as the most common etiology of GNIE, which was particularly true among PWID. Microbiologic failures occurred most commonly among P. aeruginosa , and use of combination antimicrobial therapy did not improve clinical outcomes. [ABSTRACT FROM AUTHOR]

A novel lytic Serratia liquefaciens phage, named vB_SlqM_MQ-4, was isolated from sewage. BLASTn analysis showed that the genome sequence of phage vB_SlqM_MQ-4 shared only 15% query coverage with that of Escherichia phage vB_EcoM-ep3, with 80.52% identity. Genomic analysis demonstrated that phage vB_SlqM_MQ-4 has a 43,534-bp dsDNA genome with 56% GC content and might be a member of a new genus in the order Caudoviricetes. Moreover, vB_SlqM_MQ-4 exhibited strong lytic performance with a short latent period (10 min) and a high burst size (267 PFU per cell) as well as a wide range of thermal (below 70 ℃) and pH tolerance (pH 4–12). [ABSTRACT FROM AUTHOR]