Bacterial cell wall peptidoglycan is essential, maintaining both cellular integrity and morphology, in the face of internal turgor pressure. Peptidoglycan synthesis is important, as it is targeted by cell wall antibiotics, including methicillin and vancomycin. Here, we have used the major human pathogen Staphylococcus aureus to elucidate both the cell wall dynamic processes essential for growth (life) and the bactericidal effects of cell wall antibiotics (death) based on the principle of coordinated peptidoglycan synthesis and hydrolysis. The death of S. aureus due to depletion of the essential, two-component and positive regulatory system for peptidoglycan hydrolase activity (WalKR) is prevented by addition of otherwise bactericidal cell wall antibiotics, resulting in stasis. In contrast, cell wall antibiotics kill via the activity of peptidoglycan hydrolases in the absence of concomitant synthesis. Both methicillin and vancomycin treatment lead to the appearance of perforating holes throughout the cell wall due to peptidoglycan hydrolases. Methicillin alone also results in plasmolysis and misshapen septa with the involvement of the major peptidoglycan hydrolase Atl, a process that is inhibited by vancomycin. The bactericidal effect of vancomycin involves the peptidoglycan hydrolase SagB. In the presence of cell wall antibiotics, the inhibition of peptidoglycan hydrolase activity using the inhibitor complestatin results in reduced killing, while, conversely, the deregulation of hydrolase activity via loss of wall teichoic acids increases the death rate. For S. aureus, the independent regulation of cell wall synthesis and hydrolysis can lead to cell growth, death, or stasis, with implications for the development of new control regimes for this important pathogen.
- MeSH
- antibakteriální látky farmakologie MeSH
- antiinfekční látky metabolismus farmakologie MeSH
- bakteriální proteiny metabolismus MeSH
- buněčná stěna metabolismus fyziologie MeSH
- homeostáza MeSH
- kyseliny teichoové metabolismus MeSH
- methicilin farmakologie MeSH
- N-acetylmuramoyl-L-alaninamidasa metabolismus MeSH
- peptidoglykan metabolismus MeSH
- stafylokokové infekce mikrobiologie MeSH
- Staphylococcus aureus růst a vývoj metabolismus MeSH
- vankomycin farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BackgroundInvasive infections caused by Staphylococcus aureus have high clinical and epidemiological relevance. It is therefore important to monitor the S. aureus trends using suitable methods.AimThe study aimed to describe the trends of bloodstream infections (BSI) caused by meticillin-resistant S. aureus (MRSA) and meticillin-susceptible S. aureus (MSSA) in the European Union (EU) and the European Economic Area (EEA).MethodsAnnual data on S. aureus BSI from 2005 to 2018 were obtained from the European Antimicrobial Resistance Surveillance Network (EARS-Net). Trends of BSI were assessed at the EU/EEA level by adjusting for blood culture set rate (number of blood culture sets per 1,000 days of hospitalisation) and stratification by patient characteristics.ResultsConsidering a fixed cohort of laboratories consistently reporting data over the entire study period, MRSA percentages among S. aureus BSI decreased from 30.2% in 2005 to 16.3% in 2018. Concurrently, the total number of BSI caused by S. aureus increased by 57%, MSSA BSI increased by 84% and MRSA BSI decreased by 31%. All these trends were statistically significant (p < 0.001).ConclusionsThe results indicate an increasing health burden of MSSA BSI in the EU/EEA despite a significant decrease in the MRSA percentage. These findings highlight the importance of monitoring antimicrobial resistance trends by assessing not only resistance percentages but also the incidence of infections. Further research is needed on the factors associated with the observed trends and on their attributable risk.
Rats are a reservoir of human- and livestock-associated methicillin-resistant Staphylococcus aureus (MRSA). However, the composition of the natural S. aureus population in wild and laboratory rats is largely unknown. Here, 144 nasal S. aureus isolates from free-living wild rats, captive wild rats and laboratory rats were genotyped and profiled for antibiotic resistances and human-specific virulence genes. The nasal S. aureus carriage rate was higher among wild rats (23.4%) than laboratory rats (12.3%). Free-living wild rats were primarily colonized with isolates of clonal complex (CC) 49 and CC130 and maintained these strains even in husbandry. Moreover, upon livestock contact, CC398 isolates were acquired. In contrast, laboratory rats were colonized with many different S.aureus lineages-many of which are commonly found in humans. Five captive wild rats were colonized with CC398-MRSA. Moreover, a single CC30-MRSA and two CC130-MRSA were detected in free-living or captive wild rats. Rat-derived S. aureus isolates rarely harbored the phage-carried immune evasion gene cluster or superantigen genes, suggesting long-term adaptation to their host. Taken together, our study revealed a natural S. aureus population in wild rats, as well as a colonization pressure on wild and laboratory rats by exposure to livestock- and human-associated S.aureus, respectively.
- MeSH
- antibakteriální látky farmakologie MeSH
- divoká zvířata mikrobiologie MeSH
- ekosystém MeSH
- faktory virulence genetika MeSH
- hemokoagulace MeSH
- methicilin farmakologie MeSH
- molekulární epidemiologie MeSH
- nos mikrobiologie MeSH
- potkani Sprague-Dawley MeSH
- stafylokokové infekce epidemiologie veterinární MeSH
- Staphylococcus aureus účinky léků genetika izolace a purifikace MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
- Německo MeSH
This study is aimed at detecting and characterizing methicillin-resistant Staphylococcus aureus (MRSA) from bulk tank milk samples of cows, sheep, and goats collected from dairy farms in the Czech Republic. All MRSA isolates were identified using PCR detection of the Staphylococcus aureus-specific fragment SA442 and mecA gene. The staphylococcal chromosomal cassettes mec (SCCmec), spa, and multilocus sequence types (MLST) were determined. The presence of genes encoding enterotoxins (ses), Panton-Valentine leukocidin (pvl), exfoliative toxins A, B (eta, etb), and toxic shock syndrome toxin (tst) were assessed. To differentiate human and animal origin, the presence of staphylokinase (sak) gene, ϕSa3 prophage, and susceptibility to tetracycline was tested. Out of 49 bulk tank milk samples examined, 14 (28.6%) were MRSA-positive. Eleven positive samples came from cow's milk (38%) and the remaining three from goat's milk (33%). All samples of ewe's milk were negative. In MRSA isolates three sequence types containing seven spa types were identified. Twelve isolates (85.7%) belonged to ST398 spa types t011/SCCmec IVa, t011/SCCmec V, t034/SCCmec V, t1456/SCCmec IVa, t1255/SCCmec V, and t2346/SCCmec V. Another two isolates belonged to ST5/t3598/SCCmec IVa and ST8/t064/SCCmec IVNT. In six isolates, one or more ses genes (seb, sed, seg, sei, and sej) were confirmed. One isolate from cow's milk harbored the tst gene. Another two isolates (ST398/t1456/SCCmec IVa and ST5/t3598/SCCmec IVa) harbored the sak gene and ϕSa3 prophage, and the latter was the only tetracycline-susceptible isolate in this study. However, none of the isolates was positive for pvl or eta, etb. These results suggest that there is the wide geographical spread of ST398 across different regions of the Czech Republic with no host preference among dairy cattle and goats. Therefore, when evaluating the occupational and foodborne risks, MRSA carriage and infection should be taken into account.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální proteiny genetika MeSH
- bakteriální toxiny genetika MeSH
- exotoxiny genetika MeSH
- farmy MeSH
- kozy MeSH
- leukocidiny genetika MeSH
- methicilin rezistentní Staphylococcus aureus genetika izolace a purifikace MeSH
- methicilin farmakologie MeSH
- mlékárenství MeSH
- mléko mikrobiologie MeSH
- multilokusová sekvenční typizace veterinární MeSH
- ovce MeSH
- rezistence na methicilin * MeSH
- skot MeSH
- stafylokokové infekce epidemiologie mikrobiologie veterinární MeSH
- techniky typizace bakterií veterinární MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Lytic bacteriophages are valuable therapeutic agents against bacterial infections. There is continual effort to obtain new phages to increase the effectivity of phage preparations against emerging phage-resistant strains. Here we described the genomic diversity of spontaneous host-range mutants of kayvirus 812. Five mutant phages were isolated as rare plaques on phage-resistant Staphylococcus aureus strains. The host range of phage 812-derived mutants was 42% higher than the wild type, determined on a set of 186 methicillin-resistant S. aureus strains representing the globally circulating human and livestock-associated clones. Comparative genomics revealed that single-nucleotide polymorphisms from the parental phage 812 population were fixed in next-step mutants, mostly in genes for tail and baseplate components, and the acquired point mutations led to diverse receptor binding proteins in the phage mutants. Numerous genome changes associated with rearrangements between direct repeat motifs or intron loss were found. Alterations occurred in host-takeover and terminal genomic regions or the endolysin gene of mutants that exhibited the highest lytic activity, which implied various mechanisms of overcoming bacterial resistance. The genomic data revealed that Kayvirus spontaneous mutants are free from undesirable genes and their lytic properties proved their suitability for rapidly updating phage therapeutics.
- MeSH
- bakteriální léková rezistence MeSH
- bakteriofágy genetika MeSH
- délka genomu MeSH
- genom virový MeSH
- genomika MeSH
- jednonukleotidový polymorfismus MeSH
- methicilin farmakologie MeSH
- mutace * MeSH
- Staphylococcus aureus růst a vývoj virologie MeSH
- zastoupení bazí MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
UNLABELLED: In this study, we tested 15 naturally occurring isoflavones and their metabolites for their possible antibacterial properties against nine Gram-positive and Gram-negative bacteria. The in vitro antibacterial activity was determined using the broth microdilution method, and the results were expressed as minimum inhibitory concentrations (MICs). 6,7,4'-trihydroxyisoflavone (demethyltexasin), 7,3',4'-trihydroxyisoflavone (hydroxydaidzein), 5,7-dihydroxy-4'-methoxyisoflavone (biochanin A), 7,8,4'-trihydroxyisoflavone (demethylretusin) and 5,7,4'-trihydroxyisoflavone (genistein) produced significant antibacterial activity (MICs ≥ 16 μg ml(-1)). The most effective compound, demethyltexasin, was subsequently tested for its growth-inhibitory effect against Staphylococcus aureus, and it exhibited significant antistaphylococcal effects against various standard strains and clinical isolates, including methicillin and tetracycline resistant ones with the MICs ranging from 16 to 128 μg ml(-1). SIGNIFICANCE AND IMPACT OF THE STUDY: The results of the structure-activity relationship (SAR) analysis identified ortho-dihydroxyisoflavones as a class of antibacterially effective compounds emphasizing the hydroxyl groups at C-5, 6 and 7 positions as crucial supposition for the antibacterial action of plant isoflavones and their metabolites. Demethyltexasin, an isoflavones' metabolite present in the human body through enterohepatic recycling of soya bean isoflavones (daidzein, genistein), showed the most potent antibacterial activity, especially against various strains of Staphylococcus aureus (including MDR and MRSA). The significance of this study is a deepening of the knowledge on isoflavones' SAR and identification of the antistaphylococcal activity of demethyltexasin, which suggest that metabolites of isoflavones can be even more potent antibacterial agents than their precursors.
- MeSH
- antibakteriální látky chemie farmakologie MeSH
- genistein farmakologie MeSH
- gramnegativní bakterie účinky léků MeSH
- isoflavony chemie farmakologie MeSH
- lidé MeSH
- methicilin farmakologie MeSH
- mikrobiální testy citlivosti MeSH
- rostlinné extrakty farmakologie MeSH
- Staphylococcus aureus účinky léků MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A screening method for methicillin-resistant Staphylococcus aureus (MRSA) using real-time polymerase chain reaction (PCR) and dye Syto 9 was developed and evaluated. The assay was based on the two duplex reactions run simultaneously. The detection reaction amplified staphylococcal cassette chromosome mec (SCCmec) right extremity sequences and S. aureus-specific 442-bp DNA (Sa442). The control reaction amplified S. aureus-specific nuclease gene nuc and a marker of methicillin resistance, mecA. The method was evaluated by analyzing 214 clinical S. aureus isolates yielding 98.7 % sensitivity, 100 % specificity, 100 % positive predictive value and 96.6 % negative predictive value for detection of MRSA. The detection limit was determined to be 15-80 genome copies per real-time PCR. It was able to discriminate between MRSA, methicillin resistant coagulase negative staphylococci and methicillin susceptible S. aureus (MSSA) isolates containing only small fragments of the right extremity of the SCCmec (MSSA revertants).
- MeSH
- bakteriální chromozomy genetika MeSH
- financování organizované MeSH
- lidé MeSH
- methicilin rezistentní Staphylococcus aureus genetika izolace a purifikace účinky léků MeSH
- methicilin farmakologie MeSH
- organické látky metabolismus MeSH
- polymerázová řetězová reakce metody MeSH
- prediktivní hodnota testů MeSH
- rezistence na methicilin genetika MeSH
- senzitivita a specificita MeSH
- stafylokokové infekce diagnóza mikrobiologie MeSH
- Staphylococcus aureus genetika izolace a purifikace klasifikace účinky léků MeSH
- Check Tag
- lidé MeSH
Staphylococcal hospital isolates (n = 166) were tested in a touchdown multiplex-polymerase chain reaction assay for the identification of methicillin and mupirocin resistance and discrimination of S. aureus (femA gene) from coagulase negative staphylococci and other bacteria. All isolates harbored the 16SrDNA (Staphylococcus genus specific internal control) gene, and 130 (78 %) the mecA (methicillin resistance) gene. Fifty-seven (44 %) of these were determined as methicillin-resistant S. aureus, while the remaining 73 (56 %) were methicillin-resistant coagulase-negative staphylococci. Seventy-five (45 %) isolates harbored the ileS-2 (high-level mupirocin resistance) gene and were determined as mupirocin-resistant. This assay represents a simple, rapid, reliable approach for the detection and discrimination of methicillin-and mupirocin-resistant staphylococci.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální proteiny genetika metabolismus MeSH
- DNA bakterií genetika MeSH
- lidé MeSH
- methicilin farmakologie MeSH
- mnohočetná bakteriální léková rezistence MeSH
- mupirocin farmakologie MeSH
- nemocnice MeSH
- polymerázová řetězová reakce metody MeSH
- rezistence na methicilin MeSH
- RNA ribozomální 16S genetika MeSH
- senzitivita a specificita MeSH
- stafylokokové infekce mikrobiologie MeSH
- Staphylococcus genetika izolace a purifikace účinky léků MeSH
- Check Tag
- lidé MeSH
- MeSH
- ampicilin farmakologie MeSH
- Bacteria enzymologie účinky léků MeSH
- cefaloridin farmakologie MeSH
- cefalosporiny farmakologie MeSH
- cefalothin farmakologie MeSH
- dikloxacilin farmakologie MeSH
- Enterobacteriaceae účinky léků MeSH
- Escherichia coli účinky léků MeSH
- fixní kombinace léků MeSH
- karbenicilin farmakologie MeSH
- Klebsiella účinky záření MeSH
- kloxacilin farmakologie MeSH
- methicilin farmakologie MeSH
- mikrobiální testy citlivosti MeSH
- penicilinasa metabolismus MeSH
- peniciliny farmakologie MeSH
- počet buněk MeSH
- Proteus mirabilis účinky záření MeSH
- Proteus účinky záření MeSH
- Pseudomonas aeruginosa účinky záření MeSH
- rezistence na penicilin MeSH
- synergismus léků MeSH
- MeSH
- ampicilin farmakologie MeSH
- Bacteria enzymologie účinky léků MeSH
- cefaloridin farmakologie MeSH
- cefalosporiny farmakologie MeSH
- cefalothin farmakologie MeSH
- dikloxacilin farmakologie MeSH
- Enterobacteriaceae účinky léků MeSH
- Escherichia coli účinky léků MeSH
- fixní kombinace léků MeSH
- karbenicilin farmakologie MeSH
- Klebsiella účinky léků MeSH
- kloxacilin farmakologie MeSH
- methicilin farmakologie MeSH
- mikrobiální testy citlivosti MeSH
- penicilinasa metabolismus MeSH
- peniciliny farmakologie MeSH
- počet buněk MeSH
- Proteus mirabilis účinky záření MeSH
- Proteus účinky léků MeSH
- Pseudomonas aeruginosa účinky léků MeSH
- rezistence na penicilin MeSH
- synergismus léků MeSH
