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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 ~ 10 4 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., (© 2024. The Author(s).)

Novel, white-pigmented, Gram-negative bacterial strains (K-M0706 T , K-M0228, K-M0252, K-M0260) were isolated from clinical samples. With a similarity of up to 69.7 % to Serratia nevei S15 T and up to 63.8 % to Serratia marcescens ATCC 13880 T , as determined by digital DNA-DNA hybridization, the strains were assigned as novel species of the genus Serratia. The species can easily be differentiated from the red colored Serratia marcescens sensu stricto by its white phenotype. Discrimination between this strain and Serratia nevei is possible due to alpha-glucosidase activity and O/129-resistance, as shown for strain K-M0706 T . The major fatty acids were determined as myristate, palmitate, cis-9,10-methylenehexadecanoate, linoleate, and (all cis-9,10)-methyleneoctadecanoate. These phenotypical and genomic data support the assignment of a novel species within the genus Serratia, named S. sarumanii due to its pathogenicity and white phenotype, with strain K-M0706 T as the type strain., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

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., (© 2024. The Author(s).)

Microplastics, synthetic solid particles of different sizes (< 5 mm), pose a major challenge to marine ecosystems. Introducing microplastics into the marine environment leads to the formation of complex microbial communities, a topic of growing interest in environmental research. For this study, we selected an area in the northern Adriatic Sea, less affected by human activities, to understand how pristine environmental conditions influence microbial colonization of microplastics. Samples of coastal seawater and Mediterranean mussels (Mytilus galloprovincialis) were collected in a mussel farm near Debeli rtič of the Slovenian coast. Microplastics were isolated, visually and chemically analyzed and DNA was extracted for metagenomics. In the marine water column, 12.7 microplastics per m 3 water column and 0.58 microplastics per individual mussel were found. Sufficient DNA was available to analyze six particles, five originating from seawater, and one from a mussel. This was the first-ever sequenced microplastic particle from a mussel. Genera of Pseudomonas and Serratia were identified in all samples. In one of the samples, the most abundant was a marine genus Pseudoalteromonas, while in another sample Campylobacter was present with >30 % abundance. The microbiomes of the mussel- and seawater-isolated particles were similar, suggesting a common microbial colonization pattern, which may have implications for the transfer of microplastic-associated microbes, including potential pathogens, through the food web to the consumers. Microplastic pollution is a complex issue requiring further research, especially regarding microbial biofilms, pathogen colonization and the potential of pathogen transmission via microplastic particles. Our findings enhance the understanding of microplastic pollution in the Adriatic Sea and stress the necessity for comprehensive strategies to mitigate the impact on marine ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

In this study, a combination of Serratia nematophila L2 and Bacillus velezensis W24 was used to biocontrol Sclerotinia sclerotiorum. When the mixed ratio of L2 to W24 was 1:1, the inhibition rate on the growth of S. sclerotiorum was 88.1 %. To gain a large number of bacteria, the culture medium and conditions were optimized. When the medium formula involved molasses (8.890 g/L), soy peptone (6.826 g/L), and NaCl (6.865 g/L), and the culture conditions were 32 °C, inoculum 4%, rotation speed 200 rpm, and pH 7, the maximum amounts of bacterial cells obtained. In order to prepare microcapsules, spray drying conditions were optimized. These conditions included the soluble starch concentration of 30 g/100 mL, the inlet air temperature of 160 °C, and the feed flow rate of 450 mL/h. Under these optimized conditions to prepare microcapsules, the mixed strain (L2 and W24) exhibited a survival rate of 93.9 ± 0.9% and a viable bacterial count of 6.4 × 10 12  cfu/g. In addition, microcapsules (GW24Ms) which contained strains L2 and W24 had good storage stability. In the pot experiment, GW24Ms could effectively reduce the disease of soybean plants and the control effect was 88.4%. Thus, the microbial agent represents a promising biocontrol solution for managing Sclerotinia in soybean., (Copyright © 2024 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Imported foods play an essential role in food security and in fulfilling consumer demand. However, these foods can also carry antibiotic-resistant bacteria, which might be introduced into the country of importation. Here, we report the draft genomes of antibiotic-resistant bacteria that were isolated from imported fresh produce in Georgia, USA., Competing Interests: The authors declare no conflict of interest.

Opportunistic bacterial infections are common in insect populations but there is little information on how they are acquired or transmitted. We tested the hypothesis that Macrocheles mites can transmit systemic bacterial infections between Drosophila hosts. We found that 24% of mites acquired detectable levels of bacteria after feeding on infected flies and 87% of infected mites passed bacteria to naïve recipient flies. The probability that a mite could pass Serratia from an infected donor fly to a naïve recipient fly was 27.1%. These data demonstrate that Macrocheles mites are capable of serving as vectors of bacterial infection between insects., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

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 bla NDM-1 and bla VIM-86 were observed too. bla NDM-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.

The genus Serratia harbors opportunistic pathogenic species, among which Serratia marcescens is pathogenic for honeybees although little studied. Recently, virulent strains of S. marcescens colonizing the Varroa destructor mite's mouth were found vectored into the honeybee body, leading to septicemia and death. Serratia also occurs as an opportunistic pathogen in the honeybee's gut with a low absolute abundance. The Serratia population seems controlled by the host immune system, but its presence may represent a hidden threat, ready to arise when honeybees are weakened by biotic and abiotic stressors. To shed light on the Serratia pathogen, this research aims at studying Serratia 's development dynamics in the honeybee body and its interactions with the co-occurring fungal pathogen Vairimorpha ceranae . Firstly, the degree of pathogenicity and the ability to permeate the gut epithelial barrier of three Serratia strains, isolated from honeybees and belonging to different species ( S. marcescens , Serratia liquefaciens , and Serratia nematodiphila ), were assessed by artificial inoculation of newborn honeybees with different Serratia doses (10 4 , 10 6 , and 10 8 cells/mL). The absolute abundance of Serratia in the gut and in the hemocoel was assessed in qPCR with primers targeting the luxS gene. Moreover, the absolute abundance of Serratia was assessed in the gut of honeybees infected with V. ceranae at different development stages and supplied with beneficial microorganisms and fumagillin. Our results showed that all tested Serratia strains could pass through the gut epithelial barrier and proliferate in the hemocoel, with S. marcescens being the most pathogenic. Moreover, under cage conditions, Serratia better proliferates when a V. ceranae infection is co-occurring, with a positive and significant correlation. Finally, fumagillin and some of the tested beneficial microorganisms could control both Serratia and Vairimorpha development. Our findings suggest a correlation between the two pathogens under laboratory conditions, a co-occurring infection that should be taken into consideration by researches when testing antimicrobial compounds active against V. ceranae , and the related honeybees survival rate. Moreover, our findings suggest a positive control of Serratia by the environmental microorganism Apilactobacillus kunkeei in a in vivo model, confirming the potential of this specie as beneficial bacteria for honeybees., Competing Interests: Author DS is/was employed by the company Advance Science Forbairt Eolaiochta Teo Limited. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Braglia, Alberoni, Garrido, Porrini, Baffoni, Scott, Eguaras, Di Gioia and Mifsud.)

Serratia marcescens is an opportunistic pathogen historically associated with sudden outbreaks in intensive care units (ICUs) and the spread of carbapenem-resistant genes. However, the ecology of S. marcescens populations in the hospital ecosystem remains largely unknown. We combined epidemiological information of 1,432 Serratia spp. isolates collected from sinks of a large ICU that underwent demographic and operational changes (2019-2021) and 99 non-redundant outbreak/non-outbreak isolates from the same hospital (2003-2019) with 165 genomic data. These genomes were grouped into clades (1-4) and subclades (A and B) associated with distinct species: Serratia nematodiphila (1A), S. marcescens (1B), Serratia bockelmannii (2A), Serratia ureilytica (2B), S. marcescens / Serratia nevei (3), and S. nevei (4A and 4B). They may be classified into an S. marcescens complex (SMC) due to the similarity between/within subclades (average nucleotide identity >95%-98%), with clades 3 and 4 predominating in our study and publicly available databases. Chromosomal AmpC β-lactamase with unusual basal-like expression and prodigiosin-lacking species contrasted classical features of Serratia . We found persistent and coexisting clones in sinks of subclades 4A (ST92 and ST490) and 4B (ST424), clonally related to outbreak isolates carrying bla VIM-1 or bla OXA-48 on prevalent IncL/pB77-CPsm plasmids from our hospital since 2017. The distribution of SMC populations in ICU sinks and patients reflects how Serratia species acquire, maintain, and enable plasmid evolution in both "source" (permanent, sinks) and "sink" (transient, patients) hospital patches. The results contribute to understanding how water sinks serve as reservoirs of Enterobacterales clones and plasmids that enable the persistence of carbapenemase genes in healthcare settings, potentially leading to outbreaks and/or hospital-acquired infections.IMPORTANCEThe "hospital environment," including sinks and surfaces, is increasingly recognized as a reservoir for bacterial species, clones, and plasmids of high epidemiological concern. Available studies on Serratia epidemiology have focused mainly on outbreaks of multidrug-resistant species, overlooking local longitudinal analyses necessary for understanding the dynamics of opportunistic pathogens and antibiotic-resistant genes within the hospital setting. This long-term genomic comparative analysis of Serratia isolated from the ICU environment with isolates causing nosocomial infections and/or outbreaks within the same hospital revealed the coexistence and persistence of Serratia populations in water reservoirs. Moreover, predominant sink strains may acquire highly conserved and widely distributed plasmids carrying carbapenemase genes, such as the prevalent IncL-pB77-CPsm (pOXA48), persisting in ICU sinks for years. The work highlights the relevance of ICU environmental reservoirs in the endemicity of certain opportunistic pathogens and resistance mechanisms mainly confined to hospitals., Competing Interests: The authors declare no conflict of interest.

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.

Serratia marcescens is commonly noted to be an opportunistic pathogen and is often associated with nosocomial infections. In addition to its high antibiotic resistance, it exhibits a wide range of virulence factors that confer pathogenicity. Targeting quorum sensing (QS) presents a potential therapeutic strategy for treating bacterial infections caused by S. marcescens, as it regulates the expression of various virulence factors. Inhibiting QS can effectively neutralize S. marcescens' bacterial virulence without exerting stress on bacterial growth, facilitating bacterial eradication by the immune system. In this study, the antibacterial and anti-virulence properties of eugenol against Serratia sp. were investigated. Eugenol exhibited inhibitory effects on the growth of Serratia, with a minimal inhibitory concentration (MIC) value of 16.15 mM. At sub-inhibitory concentrations, eugenol also demonstrated antiadhesive and eradication activities by inhibiting biofilm formation. Furthermore, it reduced prodigiosin production and completely inhibited protease production. Additionally, eugenol effectively decreased swimming and swarming motilities in Serratia sp. This study demonstrated through molecular modeling, docking and molecular dynamic that eugenol inhibited biofilm formation and virulence factor production in Serratia by binding to the SmaR receptor and blocking the formation of the HSL-SmaR complex. The binding of eugenol to SmaR modulates biofilm formation and virulence factor production by Serratia sp. These findings highlight the potential of eugenol as a promising agent to combat S. marcescens infections by targeting its virulence factors through quorum sensing inhibition., Competing Interests: Declaration of competing interest All authors have thoroughly reviewed and approved the manuscript, and we all concur with its submission to Microbial Pathogenesis journal. The authors declare that they have no competing interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Bacterial multimodular polyketide synthases (PKSs) are giant enzymes that generate a wide range of therapeutically important but synthetically challenging natural products. Diversification of polyketide structures can be achieved by engineering these enzymes. However, notwithstanding successes made with textbook cis -acyltransferase ( cis -AT) PKSs, tailoring such large assembly lines remains challenging. Unlike textbook PKSs, trans -AT PKSs feature an extraordinary diversity of PKS modules and commonly evolve to form hybrid PKSs. In this study, we analyzed amino acid coevolution to identify a common module site that yields functional PKSs. We used this site to insert and delete diverse PKS parts and create 22 engineered trans -AT PKSs from various pathways and in two bacterial producers. The high success rates of our engineering approach highlight the broader applicability to generate complex designer polyketides.

We report the de novo sequencing of six bacterial strains isolated from the Western honey bee, as well as the resequencing of six strains that have existing draft genomes, to obtain complete, chromosomal-level assemblies. These strains include the bee gut symbiont genera Bartonella, Bifidobacterium, Snodgrassella, Gilliamella, Lactobacillus , and the opportunistic pathogen Serratia marcescens KZ11., Competing Interests: The authors declare no conflict of interest.

Cucurbit yellow vine disease (CYVD) is caused by Serratia marcescens , vectored by squash bugs ( Anasa tristis ), and is an emerging disease in many parts of the U.S. CYVD can cause 100% yield losses in cucurbits (Bruton et al., 2003). In the summer of 2021, at the Iowa State University Horticultural Research Station (HRS) in Gilbert, Iowa, we observed leaf yellowing, vine decline, and honey-brown discoloration of the phloem of acorn squash ( Cucurbita pepo cv. Table Ace) plants in research fields that were infested with squash bugs. In 2022, we observed similar symptoms on pumpkin ( Cucurbita maxima cv. Howden) and muskmelon ( Cucumis melo cv. Athena) in different fields at the HRS and on giant pumpkins ( Cucurbita maxima cv. Prizewinner) in Jones and Ringgold counties. For up to 3 symptomatic plants of each cucurbit species per location, a 20-cm-long stem section immediately above the soil line was excised, surface sterilized by immersion in 10% sodium hypochlorite and 70% ethanol for 2 min each, then triple rinsed in sterile water. The interior of the cross-section tissue was blotted on Luria agar amended with cycloheximide (100 μg/ml) and tetracycline (20 μg/ml) (Stock et al. 2003). Whitish translucent colonies developed after incubation at 28°C for 48 h. The genomic DNA of three isolates from symptomatic plants of muskmelon (MK01), pumpkin (HFP01), and giant pumpkin (AP01), was extracted using the DNeasy Blood and Tissue Kit (Qiagen, Germantown, MD). S. marcescens species-specific primers YV1 (5'-GGGACTTGCTCCCCGG-3') and YV4 (5'-AACGTCAATTGATGAACGTATTAAGT-3') (Bruton et al. 2003) were used to amplify part of the 16S rDNA gene, and the primers specific to S. marcescens CYVD strains A79F/A79R (Zhang et al., 2005) were used to amplify part of a major facilitatory superfamily (MFS) transporter gene strain. The sequences of the 16S rRNA PCR product for the three isolates were identical and were deposited in NCBI under Accession OR963533. They shared 100% (395/395 nt) identity with other CYVD strains (Rascoe et al. 2003) and those of other S. marcescens strains in NCBI. The sequences of the amplified region of the MFS transporter gene of the three isolates (NCBI Accession OR962261) were identical and showed a 98.8% (319/323 nt) identity to that of non-CYVD-causing S. marcescens strains, such as N10A28 (Accession CP033623.1). Koch's postulates were fulfilled by inoculating C. pepo cv. Zephyr plants with either strain HFP01 or phosphate buffer saline (PBS) (10 plants per treatment) 1 wk after seeding by injecting 300 µl of bacteria (~10 8 CFU/ml) or PBS using a syringe needle. Plants were incubated at 28°C in a growth room for 4 wks. CYVD symptoms similar to those observed in the field developed on 7 out of 10 plants inoculated with strain HFP01 in one study, and 9 out 10 plants in a replicate study, with none of the PBS-inoculated plants showing CYVD symptoms. Bacteria were isolated from the symptomatic plants with selection on tetracycline. The PCR fragments amplified with YV1/YV4 and A79F/A79R were the same size as those of the pre-inoculation strain HFP01. To our knowledge this is the first report of CYVD in Iowa and in the Upper Midwest of the U.S. CYVD is a devastating disease that poses a significant threat to cucurbit production. This report can serve as an alert for the region's growers and for the development of effective management practices.

Serratia spp. is a well-recognized pathogen in neonates; however, limited data are available in adults. We studied microbiological and clinical characteristics of Serratia spp. causing bloodstream infections (BSI) in our institution (January 2005-July 2020). Overall, 141 BSI episodes affecting 139 patients were identified and medical records reviewed. Antimicrobial susceptibility was recovered from our informatics system and 118 isolates from 116 patients were available for further microbiological studies. Whole genome sequencing (WGS) was completed in 107 isolates. Incidence of Serratia BSI was 0.3/1000 overall admissions (range 0.12-0.60), with maximum prevalence (27 episodes, 19.1%) during 2017-2018. Relevant patients' clinical characteristics were 71.9% ≥60 years ( n = 100), with high comorbidity rates (49%, ≥2), 23 (74.2%) of them died within 1 month of the BSI episode. WGS identified all isolates as Serratia marcescen s when Kraken bioinformatics taxonomic tool was used despite some which were identified as Serratia nematodiphila (32/118) or Serratia ureilytica (5/118) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Nevertheless, when using MASH distance, Serratia nevei (63/107), S. ureilytica (38/107), and S. marcescens (6/107) were assigned. Carbapenemase ( bla VIM-1 ) and extended-spectrum β-lactases (ESBL) ( bla SHV-12 ) genes were found in seven and three isolates, respectively, one of them expressing both genes. The worldwide-disseminated IncL/M scaffold plasmid was identified in six VIM producers. Four genotypes were established based on their virulence factors and resistome. Serratia spp. emerged as a relevant nosocomial pathogen causing BSI in elderly patients in our hospital, particularly in recent years with a remarkable increase in antibiotic resistance. ESBL and carbapenemases production related to plasmid dissemination are particularly noteworthy.IMPORTANCE Serratia spp. is the third most frequent pathogen involved in outbreaks at neonatal facilities and is primarily associated with bacteremia episodes. In this study, we characterized all causing bloodstream infection (BSI) in patients admitted to our hospital during a 16-year period (2005-2020). Despite having no neonatal intensive care unit in our hospital, this study revealed that Serratia spp. is a relevant pathogen causing BSI in elderly patients with high comorbidity rates. A significant increase of antimicrobial resistance was detected over time, particularly in 2020 and coinciding with the coronavirus disease (COVID-19) pandemic and nosocomial spread of multidrug-resistant Serratia spp. isolates. extended-spectrum β-lactases and carbapenemases genes associated with plasmid dissemination, typically detected in other Enterobacterales species, were also identified, reinforcing the role of Serratia spp. in the antimicrobial resistance landscape. Additionally, this work highlights the need to reclassify the species of Serratia , since discrepancies were observed in the identification when using different tools., Competing Interests: The authors declare no conflict of interest.

Effective colonization on plant roots is a prerequisite for plant growth promoting rhizobacterias (PGPR) to exert beneficial activities. Light is essential for plant growth, development and stress response. However, how light modulates root colonization of PGPR remains unclear. Here, we found that high red/far red (R/FR) light promoted and low R/FR light inhibited the colonization and growth enhancement of Serratia plymuthica A21-4 (S. plymuthica A21-4) on tomato, respectively. Non-targeted metabolomic analysis of root exudates collected from different R/FR ratio treated tomato seedlings with or without S. plymuthica A21-4 inoculation by UPLC-MS/MS showed that 64 primary metabolites in high R/FR light-grown plants significantly increased compared with those determined for low R/FR light-grown plants. Among them, 7 amino acids, 1 organic acid and 1 sugar obviously induced the chemotaxis and biofilm formation of S. plymuthica A21-4 compared to the control. Furthermore, exogenous addition of five artificial root exudate compontents (leucine, methionine, glutamine, 6-aminocaproic acid and melezitose) regained and further increased the colonization ability and growth promoting ability of S. plymuthica A21-4 on tomato under low R/FR light and high R/FR light, respectively, indicating their involvement in high R/FR light-regulated the interaction of tomato root and S. plymuthica A21-4. Taken together, our results, for the first time, clearly demonstrate that high R/FR light-induced root exudates play a key role in chemotaxis, biofilm formation and root colonization of S. plymuthica A21-4. This study can help promote the combined application of light supplementation and PGPR to facilitate crop growth and health in green agricultural production., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

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-C 6 -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 .

Serratia sp. B1 is a bacterial species isolated from soil highly impacted by perfluoroalkyl and polyfluoroalkyl substances, a family of biopersistent contaminants colloquially known as "forever chemicals." Here, we report the genome of Serratia sp. B1, sequenced with Oxford Nanopore Technology. The genome consists of one 5.14 Mbp chromosome and one 92 kb plasmid., Competing Interests: The authors declare no conflict of interest.

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., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Microbial life present in the marine environment has to be able to adapt to rapidly changing and often extreme conditions. This makes these organisms a putative source of commercially interesting compounds since adaptation provides different biochemical routes from those found in their terrestrial counterparts. In this work, the goal was the identification of a marine bacterium isolated from a sample taken at a shallow water hydrothermal vent and of its red product. Genomic, lipidomic, and biochemical approaches were used simultaneously, and the bacterium was identified as Serratia rubidaea . A high-throughput screening strategy was used to assess the best physico-chemical conditions permitting both cell growth and production of the red product. The fatty acid composition of the microbial cells was studied to assess adaptation at the lipid level under stressful conditions, whilst several state-of-the-art techniques, such as DSC, FTIR, NMR, and Ultra-High Resolution Qq-Time-of-Flight mass spectrometry, were used to characterize the structure of the pigment. We hypothesize that the pigment, which could be produced by the cells up to 62 °C, is prodigiosin linked to an aliphatic compound that acts as an anchor to keep it close to the cells in the marine environment.

Introduction: The colonization of the oral cavity by potentially pathogenic antimicrobial-resistant bacteria in adolescents and its consequences is very poorly understood. The present study focused on the occurrence of oral colonization by Gram-negative bacilli (GNB) and their multidrug resistance, including the production of extended-spectrum β-lactamases (ESBLs) and carbapenemases, among healthy adolescents and risk factors associated with GNB colonization., Materials and Methods: This study was conducted as part of "A program for the early detection of risk factors for lifestyle diseases SOPKARD-Junior" (SOPKARD-Junior). Oral samples were collected from 182 adolescents from four public elementary schools in Sopot, Poland, aged 13-14 years. Bacterial strains were identified by the MALDI-TOF MS method. Screening of antimicrobial resistance was performed using a disk diffusion method. The NG-Test ® CARBA-5 was used to detect and differentiate the five most widely distributed carbapenemases. Demographic and clinical data were collected and statistical analysis of risk factors was performed., Results: A total of 68 out of 182 (37.4%) healthy adolescents was documented oral colonization with Gram-negative bacilli, including 50/182 (27.5%) multidrug resistant (MDR-GNB) strains. Over 60% of oral carriage concerned three main genera Enterobacter spp., Pseudomonas spp., and Serratia spp., which were detected in 22.1%, 19.1%, and 19.1% of participants, respectively. Citrobacter spp., Escherichia coli , Klebsiella spp., Hafnia spp., Aeromonas spp., Acinetobacter spp., and Stenotrophomonas spp. were also isolated. The antimicrobial resistance to ampicillin (100%), ceftazidime (69.1%), meropenem (60.3%), gentamycin (60.3%), piperacillin/tazobactam (52.9%), and piperacillin (45.6%) were the most common. Among 73.5% GNB strains multidrug resistance was observed, including all Pseudomonas spp. strains. Among MDR-GNB, 30.4% were resistant to four groups of antibiotics, half of the MDR Pseudomonas spp. strains were resistant to 10 groups of antibiotics. Extended-spectrum β-lactamases were produced by Enterobacter cloacae , Klebsiella spp., and Serratia spp. (7.4%). Colonization by ESBLs-positive GNB strains was significantly associated with recurrent respiratory infections, nasal congestion, and bronchitis (p<0.05)., Conclusion: Our study revealed high oral carriage of multi-drug resistant Gram-negative bacilli in healthy adolescents and the association of ESBL-producing strains with respiratory infections. Further studies on oral colonization with GNB are necessary due to the possibility of distinct infections and the acquisition of antibiotic resistance by resident microbiota., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Katkowska, Garbacz, Kwapisz, Suligowska, Kusiak, Cichońska and Świetlik.)

Background: Carbapenem-resistant Enterobacteriaceae (CRE) and Extended-spectrum beta-lactamase (ESBL) production among Gram-negative Enterobacteriaceae is an increasing global challenge due to the high morbidity and mortality associated with their infections, especially in developing countries where there are little antibiotic treatment options. Despite these challenges, few studies in Ghana have described the burden of CRE. Therefore, this study aimed to determine the prevalence of carbapenem-resistant Enterobacteriaceae isolated from patients at the Cape Coast Teaching Hospital (CCTH) in the Central region of Ghana., Methodology/principal Findings: Enterobacteriaceae isolates were collected from April to July 2019 at the bacteriology unit of CCTH using a consecutive sampling method. Isolates were identified by standard microbiological techniques and confirmed using API 20E. Kirby Bauer disc diffusion method was used to determine the antibiogram of isolates. Isolates were also subjected to ESBL testing using the single-disc combination method. Carbapenem-resistant isolates were identified by the Kirby Bauer disc diffusion method and then examined genotypically for the presence of blaKPC-1, blaIMP-1, blaVIM-1, blaNDM-1, and blaOXA-48 genes via polymerase chain reaction (PCR). Of the 230 isolates comprising E. coli (40.9%), Citrobacter spp. (32.6%), K. pneumoniae (9.1%), P. mirabilis (6.1%), P. vulgaris (5.2%), Enterobacter spp (3.5%)., K. oxytoca (2.2%), and Serratia marcenses (0.4%). Most isolates were from urine 162(70.4%) and wound samples. The isolates showed high resistance to ampicillin 171 (74.3%) and cefuroxime 134(58.3%). The prevalence of MDR was 35.2% (81), with E. coli 40(42.6%) being the majority that exhibited MDR. Of the 230 isolates, 113(49.1%) were ESBL producers, with E. coli 54(57.5%) accounting for the majority, while Serratia marcenses was the least. Of the 13 (5.7%) CRE isolates that showed resistance towards carbapenem in the disc diffusion method, 11 showed the presence of the blaNDM-1 gene, while all isolates showed the presence of the blaOXA-48 gene., Conclusion: The prevalence of carbapenem resistance and ESBL-producing Enterobacteriaceae pathogens among patients at the Cape Coast Teaching Hospital is high and alarming. Therefore, it is imperative to consider effective infection prevention and control measures should be implemented at the hospital to prevent the rapid spread of these dangerous organisms., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Sampah et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The use of bioreactor technology to treat industrial wastewater containing heavy metals has created new perspectives. Cadmium metal is one of the toxic heavy metals that have harmful effects on human health and the environment. This research work presents a comprehensive approach for aqueous cadmium removal through biosorption in a moving bed biofilm reactor (MBBR). The bacterium resistant to Cd(II) (350 mg/L) CdIW2 was selected among 8 cadmium tolerant bacteria isolated from the industrial wastewater of the metal industry. 16S rRNA gene and phenotypic analysis showed that the bacterium CdIW2 is similar to Serratia bozhouensis. The highest biosorption capacity of 65.79 mg/g was acquired in optimal conditions (30 min, pH = 6, 0.5 g/L, and 35 °C). The biosorption of the CdIW2 strain was consistent with the Langmuir isotherm and the pseudo-second order kinetic and showed the process's spontaneous thermodynamic and endothermic results. The removal rate 91.74% of MBBR in batch mode was obtained in 72 h and 10 mg/L of Cd(II). Furthermore, continuous mode bioreactor analysis has shown high efficiency at intel loading rates of 6-36 mg/L. day for cadmium removal. The second order kinetic (Grau) was chosen as the suitable model for modeling the MBBR process. Although several studies have evaluated the removal of various types of heavy metals, none of the studies involved the use of a metal-resistant strain in an MBBR bioreactor., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

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., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Plant-associated bacteria exhibit diverse chemical means to protect plants from the pathogens. The present study has been conducted to evaluate the volatile-mediated antifungal activity of Serratia sp. NhPB1 isolated from the pitcher plant against the notorious pathogen Pythium aphanidermatum. The study has also evaluated the protective effect of NhPB1 on Solanum lycopersicum and Capsicum annuum leaves and fruits against P. aphanidermatum. From the results, NhPB1 was found to have remarkable activity against the tested pathogen. The isolate was also found to impart disease protection in selected plants as evidenced by the morphological changes. Here, the leaves and fruits of S. lycopersicum and C. annuum control which were treated with the uninoculated LB and distilled water were found to have the presence of P. aphanidermatum growth with lesions and decaying of tissues. However, the NhPB1-treated plants did not show any symptoms of fungal infection. This could further be confirmed by the microscopical examination of tissues by propidium iodide staining. Here, the normal architecture of leaf and fruit tissues could be observed in the NhPB1-treated group, but the tissue invasion by P. aphanidermatum was observed in the control group which further confirms the promises of selected bacteria for biocontrol applications., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The continued emergence and spread of antimicrobial resistance among pathogenic bacteria are ever-growing threats to health and economy. Here, we report the draft genomes for 45 Enterobacterales clinical isolates, including historical and contemporary drug-resistant organisms, obtained in Pakistan between 1998 and 2016: 5 Serratia , 3 Salmonella , 3 Enterobacter , and 34 Klebsiella ., Competing Interests: The authors declare no conflict of interest.

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 ecto-ATPase 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., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

The bacterial flagellum is a rotary motor organelle and important virulence factor that propels motile pathogenic bacteria, such as Salmonella enterica, through their surroundings. Bacteriophages, or phages, are viruses that solely infect bacteria. As such, phages have myriad applications in the healthcare field, including phage therapy against antibiotic-resistant bacterial pathogens. Bacteriophage χ (Chi) is a flagellum-dependent (flagellotropic) bacteriophage, which begins its infection cycle by attaching its long tail fiber to the S. enterica flagellar filament as its primary receptor. The interactions between phage and flagellum are poorly understood, as are the reasons that χ only kills certain Salmonella serotypes while others entirely evade phage infection. In this study, we used molecular cloning, targeted mutagenesis, heterologous flagellin expression, and phage-host interaction assays to determine which domains within the flagellar filament protein flagellin mediate this complex interaction. We identified the antigenic N- and C-terminal D2 domains as essential for phage χ binding, with the hypervariable central D3 domain playing a less crucial role. Here, we report that the primary structure of the Salmonella flagellin D2 domains is the major determinant of χ adhesion. The phage susceptibility of a strain is directly tied to these domains. We additionally uncovered important information about flagellar function. The central and most variable domain, D3, is not required for motility in S. Typhimurium 14028s, as it can be deleted or its sequence composition can be significantly altered with minimal impacts on motility. Further knowledge about the complex interactions between flagellotropic phage χ and its primary bacterial receptor may allow genetic engineering of its host range for use as targeted antimicrobial therapy against motile pathogens of the χ-host genera Salmonella, Escherichia, or Serratia., Competing Interests: The authors declare no competing interests., (Copyright: © 2023 Esteves et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The Japanese pine sawyer, Monochamus saltuarius, as a beetle vector of Bursaphelenchus xylophilus (pine wood nematode), is an economically important forest pest in Eurasia. To feed on the phloem and xylem of conifers, M. saltuarius needs to overcome various stress factors, including coping with entomopathogenic bacteria and also various plant secondary compounds (PSCs). As an important adaptation strategy to colonize host trees, M. saltuarius deposit eggs in oviposition pits to shield their progeny. These pits harbor bacterial communities that are involved in the host adaptation of M. saltuarius to the conifers. However, the composition, origin, and functions of these oviposition pit bacteria are rarely understood. In this study, we investigated the bacterial community associated with M. saltuarius oviposition pits and their ability to degrade PSCs. Results showed that the bacterial community structure of M. saltuarius oviposition pits significantly differed from that of uninfected phloem. Also, the oviposition pit bacteria were predicted to be enriched in PSC degradation pathways. The microbial community also harbored a lethal strain of Serratia, which was significantly inhibited. Meanwhile, metatranscriptome analysis indicated that genes involved in PSCs degradation were expressed complementarily among the microbial communities of oviposition pits and secretions. In vitro degradation showed that bacteria cultured from oviposition pits degraded more monoterpenes and flavonoids than bacteria cultured from uninfected phloem isolates. Disinfection of oviposition pits increased the mortality of newly hatched larvae and resulted in a significant decrease in body weight in the early stages. Overall, our results reveal that M. saltuarius construct oviposition pits that harbor a diverse microbial community, with stronger PSCs degradation abilities and a low abundance of entomopathogenic bacteria, resulting in the increased fitness of newly hatched larvae., (© 2022 The Authors. Insect Science published by John Wiley & Sons Australia, Ltd on behalf of Institute of Zoology, Chinese Academy of Sciences.)

The use of biocontrol agents with plant growth-promoting activity has emerged as an approach to support sustainable agriculture. During our field evaluation of potato plants treated with biocontrol rhizobacteria, four bacteria were associated with increased plant height. Using two important solanaceous crop plants, tomato and potato, we carried out a comparative analysis of the growth-promoting activity of the four bacterial strains: Pseudomonas fluorescens SLU99, Serratia plymuthica S412, S. rubidaea AV10, and S. rubidaea EV23. Greenhouse and in vitro experiments showed that P. fluorescens SLU99 promoted plant height, biomass accumulation, and yield of potato and tomato plants, while EV23 promoted growth in potato but not in tomato plants. SLU99 induced the expression of plant hormone-related genes in potato and tomato, especially those involved in maintaining homeostasis of auxin, cytokinin, gibberellic acid and ethylene. Our results reveal potential mechanisms underlying the growth promotion and biocontrol effects of these rhizobacteria and suggest which strains may be best deployed for sustainably improving crop yield., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Hanifah, Ghadamgahi, Ghosh, Ortiz, Whisson, Vetukuri and Kalyandurg.)

The agriculture is extremely important for the life of human beings. Therefore, it is needed to control the enemies that destroy vast areas of crops causing great economic losses. Chemical pesticides were the option for many decades, but the damage that they cause to environment and human health led to the idea of changing the use of these for more sustainable options such as biopesticides as a biological control. Among microbial pesticides, Serratia species have been found as suitable options to apply against several pests or pathogens. Serratia species produce a wide range of secondary metabolites with several biological activities such as antifungal, antibacterial, and pesticides which can be used in sustainable agriculture. It has been reported that several Serratia species are able to suppress some crop diseases caused by Fusarium oxysporum, Rhizoctonia solani, Phytophthora parasitica, Sclerotinia sclerotiorum, Verticillium dahlia, and Phytophthora capsici among others. Therefore, they have been used as biocontrol agents in agriculture. In this review, we summarized the genus Serratia describing its history and development and the metabolites it secretes, which are responsible for their antibacterial and antifungal activity. We have analyzed the insecticide capacity of several Serratia species as well antifungal properties of Serratia species against most important crops' pathogens. In conclusion, the use of Serratia as a biological control agent against plant pathogens can be a good option for a sustainable agriculture. More work is needed to assess the safety of the isolated new strains and their effectiveness against pathogens in in vivo conditions., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Malaria transmission occurs when Plasmodium sporozoites are transferred from the salivary glands of anopheline mosquitoes to a human host through the injection of saliva. The need for better understanding, as well as novel modes of inhibiting, this key event in transmission has driven intense study of the protein and miRNA content of saliva. Until now the possibility that mosquito saliva may also contain bacteria has remained an open question despite the well documented presence of a rich microbiome in salivary glands., Methods: Using both 16S rRNA sequencing and MALDI-TOF approaches, we characterized the composition of the saliva microbiome of An. gambiae and An. stephensi mosquitoes which respectively represent two of the most important vectors for the major malaria-causing parasites P. falciparum and P. vivax ., Results: To eliminate the possible detection of non-mosquito-derived bacteria, we used a transgenic, fluorescent strain of one of the identified bacteria, Serratia marcescens infection modified the mosquito microbiota, increasing the presence of Serratia while diminishing the presence of Plasmodium infection modified the mosquito microbiota, increasing the presence of Serratia while diminishing the presence of Elizabethkingia and that both P. berghei and Serratia were transferred to, and colonized mammalian tissues., Discussion: These data thus document the presence of bacteria in mosquito saliva, their transfer to, and growth in a mammalian host as well as possible interactions with Plasmodium transmission. Together they raise the possible role of mosquitoes as vectors of bacterial infection and the utility of commensal mosquito bacteria for the development of transmission-blocking strategies within a mammalian host., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Accoti, Damiani, Nunzi, Cappelli, Iacomelli, Monacchia, Turco, D’Alò, Peirce, Favia and Spaccapelo.)

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 [Formula: see text]-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., (© 2022. The Author(s).)

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.

Background: Granulomatous lobular mastitis (GLM) is a rare, benign, and complex breast disease that can be easily misdiagnosed as breast cancer. The etiology of GLM is unclear, and optimal treatment has not been established., Methods: Medical records for 333 patients with GLM in recent 5 years at Longhua Hospital, Shanghai, China, were analyzed. Potential pathogens in 33 fresh tissue specimens were also analyzed using 16S rDNA sequencing technology, matrix-assisted laser desorption ionization time of flight mass spectrometry, and bacterial cultures., Results: The median age of patients was 32 years (range 22-47 years). Among 333 patients, 38.7% displayed elevated prolactin, while 23.7% displayed high interleukin-2. In the granulomatous lesion, CD3-positive T lymphocytes were significantly more than CD20-positive B lymphocytes around the vacuoles or microabscesses. Gram-positive organisms were observed in 82 cases, including in 22 cases from fresh tissue specimens. Thirty-three cases yielded associated pathogens and all displayed multiple pathogenic infections, as identified using 16S rDNA sequencing technology. Pathogenic infections were further identified as belonging to 16 main genera and 8 main pathogenic species., Conclusions: GLM displays distinct histological and clinical features similar to those that have been previously reported in the literature. Using 16S rDNA sequencing technology, all of our cases demonstrated multiple pathogenic infections, which provided more useful information for clinical treatment., Competing Interests: The authors have no conflicts of interest to declare., (Copyright © 2023 by S. Karger AG, Basel.)

Purpose: To describe clinico-microbiological features and outcomes of Serratia keratitis and to compare them with Pseudomonas aeruginosa keratitis., Methods: Cases of microbiologically proven Serratia keratitis and P. aeruginosa keratitis were reviewed. Data regarding demographic and clinical characteristics, and outcomes were recorded., Results: 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., Conclusion: 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.

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.

Focusing on visible plaques for phage isolation leaves the question if we miss the diversity of non-plaque forming phages. We addressed this question through direct plaque-based isolation by employing the new hosts Brevundimonas pondensis LVF1 and Serratia marcescens LVF3 dsDNA, ssDNA, dsRNA, and ssRNA host-associated metavirome analysis. Of the 25 distinctive dsDNA phage isolates, 14 were associated with Brevundimonas and 11 with Serratia . TEM analysis revealed that 6 were myoviruses, 18 siphoviruses and 1 podovirus, while phages infecting Brevundimonas belonged all to siphoviruses. The associated viromes suggested a higher phage diversity in summer than in winter, and dsDNA phages were the dominant group. Isolation of vB&#95;SmaP-Kaonashi was possible after investigating the viromes associated with Serratia , demonstrating the great potential of accompanying host-associated metavirome analysis. The ssDNA virome analysis showed that the B. pondensis LVF1 host is associated with Microviridae and Inoviridae phages, although none of them were isolated. The results demonstrated that the classical isolation technique is not exhausted, leading to the isolation of new dsDNA phages. It can be further improved by combination with metavirome techniques, which revealed further diversity., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Friedrich, Neubauer, Kuritsyn, Bodenberger, Tskhay, Hartmann, Poehlein, Bömeke, Hoppert, Schneider, Hertel and Daniel.)

Prior exposure to a pathogen can greatly influence the outcome of a secondary infection, and although invertebrates lack classically defined adaptive immunity, their immune response is still influenced by prior immune challenges. While the strength and specificity of such immune priming depends highly on the host organism and infecting microbe, chronic bacterial infection of the fruit fly Drosophila melanogaster with species isolated from wild-caught fruit flies provides broad nonspecific protection against a later secondary bacterial infection. To determine how chronic infection influences progression of secondary infection, we specifically tested how chronic infection with Serratia marcescens and Enterococcus faecalis impacted both resistance and tolerance to a secondary infection with an unrelated bacterium, Providencia rettgeri, by simultaneously tracking survival and bacterial load postinfection across a range of infectious doses. We found that these chronic infections increased both tolerance and resistance to P. rettgeri . Further investigation of S. marcescens chronic infection also revealed robust protection against the highly virulent Providencia sneebia, and that protection was dependent on the initial infectious dose for S. marcescens with protective doses corresponding with significantly increased diptericin expression. While the increased expression of this antimicrobial peptide gene likely explains the increased resistance, increased tolerance is likely due to other alterations in organismal physiology, such as increased negative regulation of immunity or tolerance of ER stress. These findings provide a foundation for future studies on how chronic infection influences tolerance to secondary infection.

It has been reported that cell-free culture broths and some proteins from pigmented and non-pigmented Serratia spp. are cytotoxic towards cancerous and non-cancerous human cell lines. Looking for new molecules toxic against human cancerous cells but harmless towards normal human cells, the aim of this work was (a) to determine whether cell-free broths from the entomopathogenic non-pigmented S. marcescens 81 (Sm81), S. marcescens 89 (Sm89) and S. entomophila (SeMor4.1) presented cytotoxic activity towards human carcinoma cell lines; (b) to identify and purify the associated cytotoxic factor(s) and (c) to evaluate whether the cytotoxic factor(s) was cytotoxic towards non-cancerous human cells. This research was focussed on the observed morphology changes and the proportion of remaining viable cells after incubation in the presence of cell-free culture broths from the Serratia spp isolates to evaluate cytotoxic activity. The results showed that broths from both S. marcescens isolates presented cytotoxic activity and induced cytopathic-like effects on the human neuroblastoma CHP-212 and the breast cancer MDA-MB-231 cells. Slight cytotoxicity was observed in the SeMor4.1 broth. A serralysin-like protein of 50 kDa was identified in Sm81 broth as responsible for cytotoxic activity after purification by ammonium sulphate precipitation and ion-exchange chromatography followed by tandem-mass spectrometry (LC-MS/MS). The serralysin-like protein was toxic against CHP-212 (neuroblastoma), SiHa (human cervical carcinoma) and D-54 (human glioblastoma) cell lines in a dose-dependent manner and showed no cytotoxic activity in primary cultures of normal non-cancerous human keratinocytes and fibroblasts. Therefore, this protein should be evaluated for a potential use as an anticancer agent., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The genera Serratia and Enterobacter belong to the Enterobacteriaceae family and several members have been described as plant growth-promoting rhizobacteria (PGPR). However, how these bacteria influence growth and development is unclear. We performed in vitro interaction assays between either Serratia sp. H6 or Enterobacter sp. L7 with Arabidopsis thaliana seedlings to analyze their effects on plant growth. In experiments of co-cultivation distant from the root tip, Enterobacter sp. decreased root length, markedly increased lateral root number, and slightly increased plant biomass by 33%, 230%, and 69%, respectively, and relative to the control. The volatile organic compounds (VOCs) emitted from Serratia sp. H6 but not those from Enterobacter sp. L7 promoted Arabidopsis growth. A blend of volatile compounds from the two bacteria had effects on plant growth that were similar to those observed for volatile compounds from H6 only. At several densities, the direct contact of roots with Serratia sp. H6 had phytostimulant properties but Enterobacter sp. L7 had clear deleterious effects. Together, these results suggest that direct contact and VOCs of Serratia sp. H6 were the main mechanisms to promote plant growth of A. thaliana, while diffusible compounds of Enterobacter sp. L7 were predominant in their PGPR activity., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

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., Competing Interests: Potential conflicts of interest. No funding sources were received for this study. R.K.S. has served as a consultant for Allergan, Cidara, Shionogi, Menarini, Melinta, Merck, Entasis, Utility, and Venatorx and has received investigator-initiated funding from Merck, Melinta, Shionogi, and Venatorx. All other authors report no potential conflicts., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Serratia marcescens is an aerobic, Gram-negative bacillus predominantly seen in patients with intravenous drug use, immunosuppression, previous antibiotic exposure, and indwelling catheterization. Gram-negative organism causing infective endocarditis (IE) is rare. Serratia marcescens IE is uncommon and is reported to be seen in 0.14% of all cases. In this report, we discuss in detail about a 38-year-old man with a history of intravenous drug abuse presenting with S. marcescens related prosthetic valve IE.

Objective: To objectively reveal the relationship between tongue coating microbes and bitter taste, sticky and greasy taste in chronic atrophic gastritis (CAG) patients., Methods: 16S rRNA high-throughput sequencing was used to detect bacterial diversity and community composition of tongue coating microbes from samples of CAG patients. LEfSe algorithm was used for discovering the different tongue coating microbes in CAG patients with or without bitter taste, also that in CAG patients with or without sticky and greasy taste., Results: We respectively compared the features of tongue coating microbes in bitter taste, sticky and greasy taste of CAG patients. At the genus level, 25 tongue coating microbes were significantly different in CAG patients with bitter taste or without bitter taste; 17 tongue coating microbes were significantly different in CAG patients with sticky and greasy taste or without sticky and greasy taste. and were closely related to CAG patients with bitter taste. , , and were closely related to CAG patients with stick and greasy taste., Conclusion: and possibly contribute to bitter taste of CAG patients, and and contribute to stick and greasy taste of CAG patients, which is potential for the diagnosis and treatment of CAG.

Background: Serratia spp. are opportunistic, multidrug resistant, Gram-negative pathogens, previously described among preterm infants in case reports or outbreaks of infection. We describe Serratia late-onset infection (LOI) in very preterm infants in a large, contemporary, nationally representative cohort., Methods: In this secondary analysis of prospectively collected data of preterm infants born 401-1500 grams and/or 22-29 weeks gestational age from 2018 to 2020 at 774 Vermont Oxford Network members, LOI was defined as culture-confirmed blood and/or cerebrospinal fluid infection > 3 days after birth. The primary outcome was incidence of Serratia LOI. Secondary outcomes compared rates of survival and discharge morbidities between infants with Serratia and non-Serratia LOI., Results: Among 119,565 infants, LOI occurred in 10,687 (8.9%). Serratia was isolated in 279 cases (2.6% of all LOI; 2.3 Serratia infections per 1000 infants). Of 774 hospitals, 161 (21%) reported at least one Serratia LOI; 170 of 271 (63%) cases occurred at hospitals reporting 1 or 2 Serratia infections, and 53 of 271 (20%) occurred at hospitals reporting ≥5 Serratia infections. Serratia LOI was associated with a lower rate of survival to discharge compared with those with non-Serratia LOI (adjusted relative risk 0.88, 95% CI: 0.82-0.95). Among survivors, infants with Serratia LOI had higher rates of tracheostomy, gastrostomy and home oxygen use compared with those with non-Serratia LOI., Conclusions: The incidence of Serratia LOI was 2.3 infections per 1000 very preterm infants in this cohort. Lower survival and significant morbidity among Serratia LOI survivors highlight the need for recognition and targeted prevention strategies for this opportunistic nosocomial infection., Competing Interests: S.A.C. reports receiving research funding from the National Heart, Lung and Blood Institute of the National Institutes of Health (T32HL007891). E.M.E. reports receiving salary support from Vermont Oxford Network. D.D.F. reports receiving research funding from the Agency for Healthcare Research and Quality (K08HS027468), from 2 contracts with the Centers for Disease Control and Prevention, and from the Children’s Hospital of Philadelphia. J.D.H. is the President, Chief Executive and Chief Scientific Officer of Vermont Oxford Network and is an unpaid member of the Vermont Oxford Network (VON) Board of Trustees. K.M.P. reports receiving research funding from the National Institutes of Health, from 2 contracts with the Centers for Disease Control and Prevention, and from the Children’s Hospital of Philadelphia. J.S.G. has no conflicts of interest to declare relevant to this study., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)