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PeerJ 2023is a ubiquitous bacterium from order displaying a high genetic plasticity that allows it to adapt and persist in multiple niches including soil, water, plants, and... (Review)
Review
is a ubiquitous bacterium from order displaying a high genetic plasticity that allows it to adapt and persist in multiple niches including soil, water, plants, and nosocomial environments. Recently, has gained attention as an emerging pathogen worldwide, provoking infections and outbreaks in debilitated individuals, particularly newborns and patients in intensive care units. isolates recovered from clinical settings are frequently described as multidrug resistant. High levels of antibiotic resistance across species are a consequence of the combined activity of intrinsic, acquired, and adaptive resistance elements. In this review, we will discuss recent advances in the understanding of mechanisms guiding resistance in this opportunistic pathogen.
Topics: Humans; Infant, Newborn; Serratia Infections; Serratia marcescens; Drug Resistance, Microbial; Intensive Care Units; Disease Outbreaks
PubMed: 36627920
DOI: 10.7717/peerj.14399 -
MSphere Dec 2022Bacteria can quickly adapt to constantly changing environments through a number of mechanisms, including secretion of secondary metabolites, peptides, and proteins....
Bacteria can quickly adapt to constantly changing environments through a number of mechanisms, including secretion of secondary metabolites, peptides, and proteins. Serratia marcescens, an emerging pathogen with growing clinical importance due to its intrinsic resistance to several classes of antibiotics, can cause an array of infections in immunocompromised individuals. To better control the spread of S. marcescens infections, it is critical to identify additional targets for bacterial growth inhibition. We found that extracellular metabolites produced by the wild-type organism in response to peroxide exposure had a protective effect on an otherwise-HO-sensitive indicator strain. Detailed analysis of the conditioned medium demonstrated that the protective effect was associated with a low-molecular-weight heat-sensitive and proteinase K-sensitive metabolite. Furthermore, liquid chromatography-tandem mass spectrometry analysis of the low-molecular-weight proteins present in the conditioned medium led to identification of the previously uncharacterized DUF1471-containing protein TBU67220 (SrfN). We found that loss of the gene did not have an impact on the production of extracellular enzymes. However, the S. marcescens mutant lacking SrfN was significantly more sensitive to growth in medium with a low pH and to exposure to oxidative stress. Both defects were fully rescued by complementation. Thus, our results indicate that SrfN, a low-molecular-weight DUF1471-containing protein, is involved in S. marcescens SM6 adaptation to adverse environmental conditions. Serratia marcescens is ubiquitous in the environment and can survive in water, soil, plants, insects, and animals, and it can also cause infections in humans. In the face of disturbances such as oxidative or low-pH stress, bacteria adapt, survive, and recover through several mechanisms, including changes in their secretome. We show that a hydrogen peroxide-exposed S. marcescens milieu contains a small previously uncharacterized DUF1471-containing protein similar to the SrfN protein in Salmonella enterica serovar Typhimurium, and we illustrate the role of this protein in bacterial survival during acid and oxidative stresses.
Topics: Humans; Animals; Serratia marcescens; Hydrogen Peroxide; Culture Media, Conditioned; Anti-Bacterial Agents; Oxidative Stress
PubMed: 36218346
DOI: 10.1128/msphere.00212-22 -
BMC Microbiology Jan 2022Soil fertility decline and pathogen infection are severe issues for crop production all over the world. Microbes as inherent factors in soil were effective in...
BACKGROUND
Soil fertility decline and pathogen infection are severe issues for crop production all over the world. Microbes as inherent factors in soil were effective in alleviating fertility decrease, promoting plant growth and controlling plant pathogens et al. Thus, screening microbes with fertility improving and pathogen controlling properties is of great importance to humans.
RESULTS
Bacteria Pt-3 isolated from tea rhizosphere showed multiple functions in solubilizing insoluble phosphate, promoting plant growth, producing abundant volatile organic compounds (VOCs) and inhibiting the growth of important fungal pathogens in vitro. According to the 16S rRNA phylogenetic and biochemical analysis, Pt-3 was identified to be Serratia marcescens. The solubilizing zone of Pt-3 in the medium of lecithin and Ca(PO) was 2.1 cm and 1.8 cm respectively. In liquid medium and soil, the concentration of soluble phosphorus reached 343.9 mg.L, and 3.98 mg.kg, and significantly promoted the growth of maize seedling, respectively. Moreover, Pt-3 produced abundant volatiles and greatly inhibited the growth of seven important phytopathogens. The inhibition rate ranged from 75.51 to 100% respectively. Solid phase micro-extraction coupled with gas chromatography tandem mass spectrometry proved that the antifungal volatile was dimethyl disulfide. Dimethyl disulfide can inhibit the germination of Aspergillus flavus, and severely destroy the cell structures under scanning electron microscopy.
CONCLUSIONS
S. marcescens Pt-3 with multiple functions will provide novel agent for the production of bioactive fertilizer with P-solubilizing and fungal pathogens control activity.
Topics: Antifungal Agents; Camellia sinensis; Fertilizers; Fungi; Gas Chromatography-Mass Spectrometry; Humans; Phosphates; Phylogeny; RNA, Ribosomal, 16S; Rhizosphere; Serratia marcescens; Soil Microbiology; Solubility
PubMed: 35026980
DOI: 10.1186/s12866-021-02434-5 -
In Vivo (Athens, Greece) 2024Given the characteristics of Serratia marcescens (S. marcescens), this study aimed at investigating its presence in the hands and contact lens cases of orthokeratology...
BACKGROUND/AIM
Given the characteristics of Serratia marcescens (S. marcescens), this study aimed at investigating its presence in the hands and contact lens cases of orthokeratology wearers, along with the status of bacterial contamination.
PATIENTS AND METHODS
The 39 patients received the questionnaires about the background of orthokeratology and hygiene habits. A total of 39 contact lens cases and 39 hand samples from the patients were collected at Show Chwan Memorial Hospital from June to August in 2020 and sent to National Chung Cheng University for DNA extraction and PCR identification.
RESULTS
The results indicated a detection rate of 5.13% for S. marcescens in the contact lens cases and 12.82% in the hand samples. Additionally, 66.67% of contact lens case samples and 30.77% of hand samples found positive for 16s bacterial amplicons. The relationship between hand contamination and the duration of contact lens usage were revealed for both S. marcescens (p=0.021) and 16s bacterial amplicons (p=0.048).
CONCLUSION
The results indicated that hand hygiene is more critical than focusing on contact lens hygiene when it comes to preventing S. marcescens infections. Nevertheless, both proper hand and contact lens hygiene practices can reduce the detection of bacterial eye pathogens, especially a common intestinal bacterium.
Topics: Humans; Serratia marcescens; Male; Female; Serratia Infections; Orthokeratologic Procedures; Contact Lenses; Child; Adolescent; Hygiene; Hand Hygiene; Adult; Hand
PubMed: 38688617
DOI: 10.21873/invivo.13559 -
Microbial Genomics Mar 2022is an important nosocomial pathogen causing various opportunistic infections, such as urinary tract infections, bacteremia and sometimes even hospital outbreaks. The...
is an important nosocomial pathogen causing various opportunistic infections, such as urinary tract infections, bacteremia and sometimes even hospital outbreaks. The recent emergence and spread of multidrug-resistant (MDR) strains further pose serious threats to global public health. This bacterium is also ubiquitously found in natural environments, but the genomic differences between clinical and environmental isolates are not clear, including those between and its close relatives. In this study, we performed a large-scale genome analysis of and closely related species (referred to as the ' complex'), including more than 200 clinical and environmental strains newly sequenced here. Our analysis revealed their phylogenetic relationships and complex global population structure, comprising 14 clades, which were defined based on whole-genome average nucleotide identity. Clades 10, 11, 12 and 13 corresponded to , , and , respectively. Several clades exhibited distinct genome sizes and GC contents and a negative correlation of these genomic parameters was observed in each clade, which was associated with the acquisition of mobile genetic elements (MGEs), but different types of MGEs, plasmids or prophages (and other integrative elements), were found to contribute to the generation of these genomic variations. Importantly, clades 1 and 2 mostly comprised clinical or hospital environment isolates and accumulated a wide range of antimicrobial resistance genes, including various extended-spectrum β-lactamase and carbapenemase genes, and fluoroquinolone target site mutations, leading to a high proportion of MDR strains. This finding suggests that clades 1 and 2 represent hospital-adapted lineages in the complex although their potential virulence is currently unknown. These data provide an important genomic basis for reconsidering the classification of this group of bacteria and reveal novel insights into their evolution, biology and differential importance in clinical settings.
Topics: Bacteremia; Hospitals; Humans; Phylogeny; Plasmids; Serratia marcescens
PubMed: 35315751
DOI: 10.1099/mgen.0.000793 -
FEMS Microbiology Reviews Jul 2007Many bacteria use cell-cell communication to monitor their population density, synchronize their behaviour and socially interact. This communication results in a... (Review)
Review
Many bacteria use cell-cell communication to monitor their population density, synchronize their behaviour and socially interact. This communication results in a coordinated gene regulation and is generally called quorum sensing. In gram-negative bacteria, the most common quorum signal molecules are acylated homoserine lactones (AHLs), although other low-molecular-mass signalling molecules have been described such as Autoinducer-2 (AI-2). The phenotypes that are regulated in Serratia species by means of AHLs are remarkably diverse and of profound biological and ecological significance, and often interconnected with other global regulators. Furthermore, AHL- and AI-2-mediated systems (less profoundly studied) are continuously being discovered and explored in Serratia spp., many having interesting twists on the basic theme. Therefore, this review will highlight the current known quorum sensing systems in Serratia spp., including the important nosocomial pathogen Serratia marcescens.
Topics: 4-Butyrolactone; Bacterial Proteins; Biofilms; Gene Expression Regulation, Bacterial; Homoserine; Humans; Lactones; Quorum Sensing; Serratia; Serratia marcescens; Signal Transduction
PubMed: 17459113
DOI: 10.1111/j.1574-6976.2007.00071.x -
Microbiology (Reading, England) Nov 2019is a γ-Proteobacterium and an opportunistic animal and insect pathogen. The bacterium exhibits a complex extracellular protein 'secretome' comprising numerous enzymes,...
is a γ-Proteobacterium and an opportunistic animal and insect pathogen. The bacterium exhibits a complex extracellular protein 'secretome' comprising numerous enzymes, toxins and effector molecules. One component of the secretome is the 'chitinolytic machinery', which is a set of at least four chitinases that allow the use of insoluble extracellular chitin as sole carbon source. Secretion of the chitinases across the outer membrane is governed by the operon encoding a holin/endopeptidase pair. Expression of the operon is co-ordinated with the chitinase genes and is also bimodal, as normally only 1% of the population expresses the chitinolytic machinery. In this study, the role of the ChiR protein in chitinase production has been explored. Using live cell imaging and flow cytometry, ChiR was shown to govern the co-ordinated regulation of with both and . Moreover, overexpression of alone was able to increase the proportion of the cell population expressing chitinase genes to >60 %. In addition, quantitative label-free proteomic analysis of cells overexpressing established that ChiR regulates the entire chitinolytic machinery. The proteomic experiments also revealed a surprising link between the regulation of the chitinolytic machinery and the production of proteins involved in the metabolism of nitrogen compounds such as nitrate and nitrite. The research demonstrates for the first time that ChiR plays a critical role in controlling bimodal gene expression in , and provides new evidence of a clear link between chitin breakdown and nitrogen metabolism.
Topics: Bacterial Proteins; Chitinases; Flow Cytometry; Gene Expression; Gene Expression Regulation, Bacterial; Microscopy, Fluorescence; Mutation; Nitrogen Compounds; Operon; Proteomics; Serratia marcescens; Transcription Factors
PubMed: 31526448
DOI: 10.1099/mic.0.000856 -
Journal of Bacteriology Jun 2021Serratia marcescens is an enteric bacterium that can function as an opportunistic pathogen with increasing incidence in clinical settings. This is mainly due to the...
Serratia marcescens is an enteric bacterium that can function as an opportunistic pathogen with increasing incidence in clinical settings. This is mainly due to the ability to express a wide range of virulence factors and the acquisition of antibiotic resistance mechanisms. For these reasons, S. marcescens has been declared by the World Health Organization (WHO) as a research priority to develop alternative antimicrobial strategies. In this study, we found a PhoP-binding motif in the promoter region of transcriptional regulator RamA of S. marcescens RM66262. We demonstrated that the expression of is autoregulated and that is also part of the PhoP/PhoQ regulon. We have also shown that PhoP binds directly and specifically to , , , , and promoter regions and that RamA binds to and but not to and , suggesting an indirect control for the latter genes. Finally, we have demonstrated that in S. marcescens, RamA overexpression induces the AcrAB-TolC efflux pump, required to reduce the susceptibility of the bacteria to tetracycline and nalidixic acid. In sum, we here provide the first report describing the regulation of under the control of the PhoP/PhoQ regulon and the regulatory role of RamA in S. marcescens. We demonstrate that in S. marcescens, the transcriptional regulator RamA is autoregulated and also controlled by the PhoP/PhoQ signal transduction system. We show that PhoP is able to directly and specifically bind to , , , , and promoter regions. In addition, RamA is able to directly interact with the promoter regions of and but indirectly regulates and . Finally, we found that in S. marcescens, RamA overexpression induces the AcrAB-TolC efflux pump, required to reduce susceptibility to tetracycline and nalidixic acid. Collectively, these results further our understanding of the PhoP/PhoQ regulon in S. marcescens and demonstrate the involvement of RamA in the protection against antibiotic challenges.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Chloramphenicol; Drug Resistance, Microbial; Gastrointestinal Microbiome; Gene Expression Regulation, Bacterial; Homeostasis; Lipid A; Nalidixic Acid; Phenotype; Regulon; Serratia marcescens; Signal Transduction; Tetracycline; Transcription Factors; Transcription, Genetic; Virulence Factors
PubMed: 33927048
DOI: 10.1128/JB.00523-20 -
Epigenetics Aug 2022Epigenetic modifications can contribute to adaptation, but the relative contributions of genetic and epigenetic variation are unknown. Previous studies on the role of...
Epigenetic modifications can contribute to adaptation, but the relative contributions of genetic and epigenetic variation are unknown. Previous studies on the role of epigenetic changes in adaptation in eukaryotes have nearly exclusively focused on cytosine methylation (m5C), while prokaryotes exhibit a richer system of methyltransferases targetting adenines (m6A) or cytosines (m4C, m5C). DNA methylation in prokaryotes has many roles, but its potential role in adaptation still needs further investigation. We collected phenotypic, genetic, and epigenetic data using single molecule real-time sequencing of clones of the bacterium that had undergone experimental evolution in contrasting temperatures to investigate the relationship between environment and genetic, epigenetic, and phenotypic changes. The genomic distribution of GATC motifs, which were the main target for m6A methylation, and of variable m6A epiloci pointed to a potential link between m6A methylation and regulation of gene expression in . Evolved strains, while genetically homogeneous, exhibited many polymorphic m6A epiloci. There was no strong support for a genetic control of methylation changes in our experiment, and no clear evidence of parallel environmentally induced or environmentally selected methylation changes at specific epiloci was found. Both genetic and epigenetic variants were associated with some phenotypic traits. Overall, our results suggest that both genetic and adenine methylation changes have the potential to contribute to phenotypic adaptation in , but that any environmentally induced epigenetic change occurring in our experiment would probably have been quite labile.
Topics: Adenine; DNA Methylation; Epigenesis, Genetic; Mutation; Serratia marcescens; Temperature
PubMed: 34519613
DOI: 10.1080/15592294.2021.1966215 -
Applied and Environmental Microbiology Jan 2021Prodigiosin (PG), a red linear tripyrrole pigment normally secreted by , has received attention for its reported immunosuppressive, antimicrobial, and anticancer...
Prodigiosin (PG), a red linear tripyrrole pigment normally secreted by , has received attention for its reported immunosuppressive, antimicrobial, and anticancer properties. Although several genes have been shown to be important for prodigiosin synthesis, information on the regulatory mechanisms behind this cellular process remains limited. In this work, we identified that the transcriptional regulator RcsB encoding gene () negatively controlled prodigiosin biosynthesis in Disruption of conferred a remarkably increased production of prodigiosin. This phenotype corresponded to negative control of transcription of the prodigiosin-associated operon by RcsB, probably by binding to the promoter region of the prodigiosin synthesis positive regulator FlhDC. Moreover, using transcriptomics and further experiments, we revealed that RcsB also controlled some other important cellular processes, including swimming and swarming motilities, capsular polysaccharide production, biofilm formation, and acid resistance (AR), in Collectively, this work proposes that RcsB is a prodigiosin synthesis repressor in and provides insight into the regulatory mechanism of RcsB in cell motility, capsular polysaccharide production, and acid resistance in RcsB is a two-component response regulator in the Rcs phosphorelay system, and it plays versatile regulatory functions in However, information on the function of the RcsB protein in bacteria, especially in , remains limited. In this work, we illustrated experimentally that the RcsB protein was involved in diverse cellular processes in , including prodigiosin synthesis, cell motility, capsular polysaccharide production, biofilm formation, and acid resistance. Additionally, the regulatory mechanism of the RcsB protein in these cellular processes was investigated. In conclusion, this work indicated that RcsB could be a regulator for prodigiosin synthesis and provides insight into the function of the RcsB protein in .
Topics: Bacterial Proteins; Gene Expression Regulation, Bacterial; Operon; Prodigiosin; Serratia marcescens
PubMed: 33158890
DOI: 10.1128/AEM.02052-20