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Antimicrobial Agents and Chemotherapy May 2017is one of the primary causes of nosocomial infections. Disinfectants are commonly used to prevent infections with multidrug-resistant in hospitals. Worryingly,...
is one of the primary causes of nosocomial infections. Disinfectants are commonly used to prevent infections with multidrug-resistant in hospitals. Worryingly, strains that exhibit tolerance to disinfectants have already been described. We aimed to identify and characterize genes that contribute to tolerance to the disinfectant chlorhexidine (CHX). We used a transposon mutant library, constructed in a multidrug-resistant bloodstream isolate, to perform a genome-wide screen to identify genetic determinants involved in tolerance to CHX. We identified a putative two-component system (2CS), composed of a putative sensor histidine kinase (ChtS) and a cognate DNA-binding response regulator (ChtR), which contributed to CHX tolerance in Targeted and deletion mutants exhibited compromised growth in the presence of CHX. Growth of the and mutants was also affected in the presence of the antibiotic bacitracin. The CHX- and bacitracin-tolerant phenotype of E1162 was linked to a unique, nonsynonymous single nucleotide polymorphism in Transmission electron microscopy showed that upon challenge with CHX, the Δ and Δ mutants failed to divide properly and formed long chains. Normal growth and cell morphology were restored when the mutations were complemented in Morphological abnormalities were also observed upon exposure of the Δ and Δ mutants to bacitracin. The tolerance to both chlorhexidine and bacitracin provided by ChtRS in highlights the overlap between responses to disinfectants and antibiotics and the potential for the development of cross-tolerance for these classes of antimicrobials.
Topics: Anti-Bacterial Agents; Bacitracin; Bacterial Proteins; Chlorhexidine; DNA-Binding Proteins; Disinfectants; Drug Resistance, Multiple, Bacterial; Enterococcus faecium; Histidine Kinase; Microbial Sensitivity Tests; Polymorphism, Single Nucleotide
PubMed: 28242664
DOI: 10.1128/AAC.02122-16 -
International Journal of... 2023The variety of morphological and cultural characteristics of acid-resistant bacteria (ARB) makes it possible to use microscopy and estimate the growth rate and pigment...
BACKGROUND
The variety of morphological and cultural characteristics of acid-resistant bacteria (ARB) makes it possible to use microscopy and estimate the growth rate and pigment formation when cultivating on solid egg media for preliminary identification only as additional indicative methods. It is necessary to develop new approaches for the cultivation and primary identification of ARB isolated from the biological material. It will allow to obtain data on the prevalence, structure, epidemiological, and clinical features of infectious processes caused by opportunistic ARB.
METHODS
Three hundred and sixty strains of ARB were isolated from the various biological materials obtained from the patients during the examination for tuberculosis. All biological material samples were negative on Mycobacteria tuberculosis complex. Species identification of all bacteria was performed by matrix-assisted lazer desorption/ion-ization time-of-flight mass spectrometry. The cultural characteristics of ARB were evaluated on a universal chromogenic media. As a selective additive, a mixture of bacitracin and polymyxin sulfate which had no effect on ARB was tested to suppress concomitant Gram-positive and Gram-negative microflora.
RESULTS
Cultural characteristics were identified and described for all tested representatives of fast-growing nontuberculous mycobacteria (NTM), as well as for all types of nocardia, gordonia, and streptomycetes. Representatives of other genera of ARB on a universal chromogenic media gave meager growth or did not show it at all. When inoculated on a universal chromogenic media with a selective addition, 100% of the strains from the ARB group showed abundant or moderate growth. Incubation time for fast-growing species was up to 7 days; for slow-growing species, it was up to 28 days. Concomitant control strains of Gram-positive and Gram-negative bacteria on universal chromogenic media with selective growth additive did not show the growth.
CONCLUSIONS
The use of a universal chromogenic media allows to preliminarily identify NTM and other ARB by cultural characteristics. The addition of bacitracin and polymyxin sulfate does not reduce the growth properties of ARB, which can be used when working with both biological materials and for the isolation of pure ARB cultures from mixtures with other bacteria.
Topics: Humans; Angiotensin Receptor Antagonists; Anti-Bacterial Agents; Bacitracin; Gram-Negative Bacteria; Angiotensin-Converting Enzyme Inhibitors; Gram-Positive Bacteria; Tuberculosis; Mycobacterium; Nontuberculous Mycobacteria; Culture Media
PubMed: 36926763
DOI: 10.4103/ijmy.ijmy_6_23 -
Frontiers in Cellular and Infection... 2022, a Gram-positive facultative anaerobic bacterium, is a major pathogen of dental caries. The protein Cnm of is involved in collagen binding, but its other biological...
, a Gram-positive facultative anaerobic bacterium, is a major pathogen of dental caries. The protein Cnm of is involved in collagen binding, but its other biological functions are unknown. In this study, a Cnm-deficient isogenic mutant and a complementation strain were generated from a Cnm-positive strain to help determine the properties of Cnm. Initially, comparison of the cell surface structure was performed by electron microscopy, which demonstrated that Cnm appears to be localized on the cell surface and associated with a protruding cell surface structure. Deep RNA sequencing of the strains revealed that the defect in Cnm caused upregulated expression of many genes related to ABC transporters and cell-surface proteins, while a few genes were downregulated. The amount of biofilm formed by the Cnm-defective strain increased compared with the parental and complemented strains, but the biofilm structure was thinner because of elevated expression of genes encoding glucan synthesis enzymes, leading to increased production of extracellular polysaccharides. Particular antibiotics, including bacitracin and chloramphenicol, had a lower minimum inhibitory concentration for the Cnm-defective strain than particular antibiotics, including bacitracin and chloramphenicol, compared with the parental and complemented strains. Our results suggest that Cnm is located on the cell surface, gives rise to the observed protruding cell surface, and is associated with several biological properties related to membrane permeability.
Topics: ATP-Binding Cassette Transporters; Adhesins, Bacterial; Anti-Bacterial Agents; Bacitracin; Base Composition; Biofilms; Carrier Proteins; Chloramphenicol; Collagen; Glucans; Membrane Proteins; Permeability; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Streptococcus mutans
PubMed: 36176579
DOI: 10.3389/fcimb.2022.994014 -
Antimicrobial Agents and Chemotherapy 2014Resistance of Enterococcus faecalis against antimicrobial peptides, both of host origin and produced by other bacteria of the gut microflora, is likely to be an...
Resistance of Enterococcus faecalis against antimicrobial peptides, both of host origin and produced by other bacteria of the gut microflora, is likely to be an important factor in the bacterium's success as an intestinal commensal. The aim of this study was to identify proteins with a role in resistance against the model antimicrobial peptide bacitracin. Proteome analysis of bacitracin-treated and untreated cells showed that bacitracin stress induced the expression of cell wall-biosynthetic proteins and caused metabolic rearrangements. Among the proteins with increased production, an ATP-binding cassette (ABC) transporter with similarity to known peptide antibiotic resistance systems was identified and shown to mediate resistance against bacitracin. Expression of the transporter was dependent on a two-component regulatory system and a second ABC transporter, which were identified by genome analysis. Both resistance and the regulatory pathway could be functionally transferred to Bacillus subtilis, proving the function and sufficiency of these components for bacitracin resistance. Our data therefore show that the two ABC transporters and the two-component system form a resistance network against antimicrobial peptides in E. faecalis, where one transporter acts as the sensor that activates the TCS to induce production of the second transporter, which mediates the actual resistance.
Topics: ATP-Binding Cassette Transporters; Anti-Bacterial Agents; Bacitracin; Drug Resistance, Bacterial; Enterococcus faecalis; Gene Expression Regulation, Bacterial; Microbial Sensitivity Tests; Promoter Regions, Genetic; Proteome
PubMed: 24342648
DOI: 10.1128/AAC.02111-13 -
BMC Research Notes Sep 2017To determine the effect of bacitracin methylene disalicylate (BMD) and feed changes on gastrointestinal integrity, endotoxin permeability, and morphometric parameters in...
OBJECTIVE
To determine the effect of bacitracin methylene disalicylate (BMD) and feed changes on gastrointestinal integrity, endotoxin permeability, and morphometric parameters in the duodenum of broilers.
RESULTS
Birds were raised on a starter diet without growth promoting antibiotics for 31 days then switched to a grower diet. Four of the pens including 50 g/ton of BMD while 4 pens remained antibiotic free. Eight birds per treatment were sampled prior to the feed change and at 3 and 7 days following the feed change. Gastrointestinal integrity and endotoxin permeability in the duodenum were determined using a modified Ussing Chamber and an adjacent section fixed in 10% formalin for morphometric analysis. Data were analyzed using Proc Glimmix of SAS with the model fitting BMD treatment, time, and the interaction of BMD treatment and time as fixed effects. Intestinal integrity increased at d 3 and 7 compared to prior to the feed change and addition of BMD (P > 0.001) and villus height was decreased with BMD supplementation (P = 0.049). All other tested effects similar (P > 0.1). In conclusion, the practice of changing feed had a greater effect on intestinal health than addition of BMD. However, the factors driving these differences 42 are unclear.
Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Anti-Bacterial Agents; Bacitracin; Chickens; Diet; Duodenum; Endotoxins; Salicylates
PubMed: 28886731
DOI: 10.1186/s13104-017-2781-8 -
Scientific Reports Mar 2022Treatment of bacterial infections is one of the major challenges of our time due to the evolved resistance mechanisms of pathogens against antibiotics. To circumvent...
Treatment of bacterial infections is one of the major challenges of our time due to the evolved resistance mechanisms of pathogens against antibiotics. To circumvent this problem, it is necessary to understand the mode of action of the drug and the mechanism of resistance of the pathogen. One of the most potent antibiotic targets is peptidoglycan (PGN) biosynthesis, as this is an exclusively occurring and critical feature of bacteria. Lipid II is an essential PGN precursor synthesized in the cytosol and flipped into the outer leaflet of the membrane prior to its incorporation into nascent PGN. Antimicrobial peptides (AMPs), such as nisin and colistin, targeting PGN synthesis are considered promising weapons against multidrug-resistant bacteria. However, human pathogenic bacteria that were also resistant to these compounds evolved by the expression of an ATP-binding cassette transporter of the bacitracin efflux (BceAB) type localized in the membrane. In the human pathogen Streptococcus agalactiae, the BceAB transporter SaNsrFP is known to confer resistance to the antimicrobial peptide nisin. The exact mechanism of action for SaNsrFP is poorly understood. For a detailed characterization of the resistance mechanism, we heterologously expressed SaNsrFP in Lactococcus lactis. We demonstrated that SaNsrFP conferred resistance not only to nisin but also to a structurally diverse group of antimicrobial PGN-targeting compounds such as ramoplanin, lysobactin, or bacitracin/(Zn)-bacitracin. Growth experiments revealed that SaNsrFP-producing cells exhibited normal behavior when treated with nisin and/or bacitracin, in contrast to the nonproducing cells, for which growth was significantly reduced. We further detected the accumulation of PGN precursors in the cytoplasm after treating the cells with bacitracin. This did not appear when SaNsrFP was produced. Whole-cell proteomic protein experiments verified that the presence of SaNsrFP in L. lactis resulted in higher production of several proteins associated with cell wall modification. These included, for example, the N-acetylmuramic acid-6-phosphate etherase MurQ and UDP-glucose 4-epimerase. Analysis of components of the cell wall of SaNsrFP-producing cells implied that the transporter is involved in cell wall modification. Since we used an ATP-deficient mutant of the transporter as a comparison, we can show that SaNsrFP and its inactive mutant do not show the same phenotype, albeit expressed at similar levels, which demonstrates the ATP dependency of the mediated resistance processes. Taken together, our data agree to a target protection mechanism and imply a direct involvement of SaNsrFP in resistance by shielding the membrane-localized target of these antimicrobial peptides, resulting in modification of the cell wall.
Topics: Adenosine Triphosphate; Anti-Bacterial Agents; Bacitracin; Bacterial Proteins; Drug Resistance, Bacterial; Membrane Transport Proteins; Nisin; Proteomics
PubMed: 35273305
DOI: 10.1038/s41598-022-08095-2 -
Frontiers in Cellular and Infection... 2022Preeclampsia (PE) is a pregnancy complication characterized by severe hypertension and multiple organ damage. Gut microbiota has been linked to PE by previous amplicon...
Preeclampsia (PE) is a pregnancy complication characterized by severe hypertension and multiple organ damage. Gut microbiota has been linked to PE by previous amplicon sequencing studies. To resolve the PE gut microbiota in a higher taxonomy resolution, we performed shotgun metagenomic sequencing on the fecal samples from 40 early-onset PE and 37 healthy pregnant women. We recovered 1,750 metagenome-assembled genomes (representing 406 species) from the metagenomic dataset and profiled their abundances. We found that PE gut microbiota had enriched in some species belonging to , , , and and microbial functions such as the bacitracin/lantibiotics transport system, maltooligosaccharide transport system, multidrug efflux pump, and rhamnose transport system. Conversely, the gut microbiome of healthy pregnant women was enriched in species of and and microbial functions including the porphyrin and chlorophyll metabolism, pyridoxal-P biosynthesis, riboflavin metabolism, and folate biosynthesis pathway. PE diagnostic potential of gut microbial biomarkers was developed using both species and function profile data. These results will help to explore the relationships between gut bacteria and PE and provide new insights into PE early warning.
Topics: Bacitracin; Bacteriocins; Biomarkers; Chlorophyll; Dysbiosis; Feces; Female; Folic Acid; Humans; Metagenome; Microbiota; Porphyrins; Pre-Eclampsia; Pregnancy; Pyridoxal Phosphate; RNA, Ribosomal, 16S; Rhamnose; Riboflavin
PubMed: 36189343
DOI: 10.3389/fcimb.2022.933523 -
MSphere Aug 2021Listeria monocytogenes is a foodborne pathogen and a resilient environmental saprophyte. Dairy farms are a reservoir of L. monocytogenes, and strains can persist on...
Listeria monocytogenes is a foodborne pathogen and a resilient environmental saprophyte. Dairy farms are a reservoir of L. monocytogenes, and strains can persist on farms for years. Here, we sequenced the genomes of 250 L. monocytogenes isolates to investigate the persistence and mobile genetic elements (MGEs) of strains inhabiting dairy farms. We performed a single-nucleotide polymorphism (SNP)-based phylogenomic analysis to identify 14 monophyletic clades of L. monocytogenes persistent on the farms for ≥6 months. We found that prophages and other mobile genetic elements were, on average, more numerous among isolates in persistent than nonpersistent clades, and we demonstrated that resistance genes against bacitracin, arsenic, and cadmium were significantly more prevalent among isolates in persistent than nonpersistent clades. We identified a diversity of mobile elements among the 250 farm isolates, including three novel plasmids, three novel transposons, and a novel prophage harboring cadmium resistance genes. Several of the mobile elements we identified in Listeria were identical to the mobile elements of enterococci, which is indicative of recent transfer between these genera. Through a genome-wide association study, we discovered that three putative defense systems against invading prophages and plasmids were negatively associated with persistence on farms. Our findings suggest that mobile elements support the persistence of L. monocytogenes on dairy farms and that L. monocytogenes inhabiting the agroecosystem is a potential reservoir of mobile elements that may spread to the food industry. Animal-derived raw materials are an important source of L. monocytogenes in the food industry. Knowledge of the factors contributing to the pathogen's transmission and persistence on farms is essential for designing effective strategies against the spread of the pathogen from farm to fork. An increasing body of evidence suggests that mobile genetic elements support the adaptation and persistence of L. monocytogenes in the food industry, as these elements contribute to the dissemination of genes encoding favorable phenotypes, such as resilience against biocides. Understanding of the role of farms as a potential reservoir of these elements is needed for managing the transmission of mobile elements across the food chain. Because L. monocytogenes coinhabits the farm ecosystem with a diversity of other bacterial species, it is important to assess the degree to which genetic elements are exchanged between and other species, as such exchanges may contribute to the rise of novel resistance phenotypes.
Topics: Animals; Anti-Bacterial Agents; Bacitracin; Cattle; Dairying; Genome, Bacterial; Interspersed Repetitive Sequences; Listeria monocytogenes; Metals, Heavy; Phylogeny; Polymorphism, Single Nucleotide; Prophages; Virulence Factors; Whole Genome Sequencing
PubMed: 34232074
DOI: 10.1128/mSphere.00383-21 -
Molecular Microbiology Aug 2011Two-component systems (TCSs) are key regulatory pathways allowing bacteria to adapt their genetic expression to environmental changes. Bacitracin, a cyclic...
Bacitracin and nisin resistance in Staphylococcus aureus: a novel pathway involving the BraS/BraR two-component system (SA2417/SA2418) and both the BraD/BraE and VraD/VraE ABC transporters.
Two-component systems (TCSs) are key regulatory pathways allowing bacteria to adapt their genetic expression to environmental changes. Bacitracin, a cyclic dodecylpeptide antibiotic, binds to undecaprenyl pyrophosphate, the lipid carrier for cell wall precursors, effectively inhibiting peptidoglycan biosynthesis. We have identified a novel and previously uncharacterized TCS in the major human pathogen Staphylococcus aureus that we show to be essential for bacitracin and nisin resistance: the BraS/BraR system (Bacitracin resistance associated; SA2417/SA2418). The braRS genes are located immediately upstream from genes encoding an ABC transporter, accordingly designated BraDE. We have shown that the BraSR/BraDE module is a key bacitracin and nisin resistance determinant in S. aureus. In the presence of low antibiotic concentrations, BraSR activate transcription of two operons encoding ABC transporters: braDE and vraDE. We identified a highly conserved imperfect palindromic sequence upstream from the braDE and vraDE promoter sequences, essential for their transcriptional activation by BraSR, suggesting it is the likely BraR binding site. We demonstrated that the two ABC transporters play distinct and original roles in antibiotic resistance: BraDE is involved in bacitracin sensing and signalling through BraSR, whereas VraDE acts specifically as a detoxification module and is sufficient to confer bacitracin and nisin resistance when produced on its own. We show that these processes require functional BraD and VraD nucleotide-binding domain proteins, and that the large extracellular loop of VraE confers its specificity in bacitracin resistance. This is the first example of a TCS associated with two ABC transporters playing separate roles in signal transduction and antibiotic resistance.
Topics: ATP-Binding Cassette Transporters; Adaptation, Physiological; Amino Acid Sequence; Antimicrobial Cationic Peptides; Bacitracin; Base Sequence; Drug Resistance, Bacterial; Gene Expression Regulation, Bacterial; Humans; Microbial Sensitivity Tests; Models, Biological; Molecular Sequence Data; Multigene Family; Nisin; Operon; Promoter Regions, Genetic; Sequence Alignment; Signal Transduction; Staphylococcus aureus
PubMed: 21696458
DOI: 10.1111/j.1365-2958.2011.07735.x -
Anesthesiology Aug 1981
Review
Topics: Aminoglycosides; Anti-Bacterial Agents; Bacitracin; Bacteria; Cell Membrane Permeability; Cell Wall; Clindamycin; Drug Hypersensitivity; Drug Interactions; Gentamicins; Humans; Kanamycin; Lincomycin; Muscle Proteins; Neomycin; Neuromuscular Junction; Nucleic Acids; Penicillins; Polymyxins; Streptomycin; Tetracyclines
PubMed: 6266284
DOI: 10.1097/00000542-198108000-00011