BACKGROUND: A novel Panton-Valentine leukocidin (PVL)-positive meticillin-resistant Staphylococcus aureus (MRSA) clonal complex (CC)5-MRSA-IVc ('Sri Lankan' clone) was recently described from Sri Lanka. Similar isolates caused a recent Irish hospital outbreak. AIM: To investigate the international dissemination and diversity of PVL-positive CC5-MRSA-IVc isolates from hospital and community settings using whole-genome sequencing (WGS). METHODS: Core-genome single nucleotide polymorphism (cgSNP) analysis, core-genome multi-locus sequence typing (cgMLST) and microarray-based detection of antimicrobial-resistance and virulence genes were used to investigate PVL-positive CC5-MRSA-IVc (N = 214 including 46 'Sri Lankan' clone) from hospital and community settings in 12 countries over 17 years. Comparators included 29 PVL-positive and 23 PVL-negative CC5/ST5-MRSA-I/II/IVa/IVc/IVg/V. RESULTS: Maximum-likelihood cgSNP analysis grouped 209/214 (97.7%) CC5-MRSA-IVc into Clade I; average of 110 cgSNPs between isolates. Clade III contained the five remaining CC5-MRSA-IVc; average of 92 cgSNPs between isolates. Clade II contained seven PVL-positive CC5-MRSA-IVa comparators, whereas the remaining 45 comparators formed an outlier group. Minimum-spanning cgMLST analysis revealed a comparably low average of 57 allelic differences between all CC5/ST5-MRSA-IVc. All 214 CC5/ST5-MRSA-IVc were identified as 'Sri Lankan' clone, predominantly spa type t002 (186/214) with low population diversity and harboured a similar range of virulence genes and variable antimicrobial-resistance genes. All 214 Sri Lankan clone isolates and Clade II comparators harboured a 9616-bp chromosomal PVL-encoding phage remnant, suggesting both arose from a PVL-positive meticillin-susceptible ancestor. Over half of Sri Lankan clone isolates were from infections (142/214), and where detailed metadata were available (168/214), most were community associated (85/168). CONCLUSIONS: Stable chromosomal retention of pvl may facilitate Sri-Lankan clone dissemination.
- MeSH
- Exotoxins genetics MeSH
- Leukocidins genetics MeSH
- Humans MeSH
- Methicillin-Resistant Staphylococcus aureus * MeSH
- Methicillin MeSH
- Microbial Sensitivity Tests MeSH
- Multilocus Sequence Typing MeSH
- Hospitals MeSH
- Staphylococcal Infections * epidemiology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
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
- Anti-Bacterial Agents pharmacology MeSH
- Anti-Infective Agents metabolism pharmacology MeSH
- Bacterial Proteins metabolism MeSH
- Cell Wall metabolism physiology MeSH
- Homeostasis MeSH
- Teichoic Acids metabolism MeSH
- Methicillin pharmacology MeSH
- N-Acetylmuramoyl-L-alanine Amidase metabolism MeSH
- Peptidoglycan metabolism MeSH
- Staphylococcal Infections microbiology MeSH
- Staphylococcus aureus growth & development metabolism MeSH
- Vancomycin pharmacology MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't 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.
Recently, the interest is increasing to find alternatives to replace the usage of antibiotics since their massive and improper usage enhance the antibiotic resistance in human pathogens. In this study, for the first time we showed that the soil proteins have very high antibacterial activity (98% of growth inhibition) against methicillin resistant Staphylococcus aureus (MRSA), one of the most threatening human pathogens. We found that the protein extract (C3) from the forest with past intensive management showed higher antibacterial activity than that of unmanaged forest. The MIC and IC50 were found to be 30 and 15.0 μg protein g-1 dry soil respectively. C3 was found to kill the bacteria by cell wall disruption and genotoxicity which was confirmed by optical and fluorescent microscopy and comet assay. According to qPCR study, the mecA (the antibiotic resistant gene) expression in MRSA was found to be down-regulated after C3 treatment. In contrast, C3 showed no hemolytic toxicity on human red blood cells which was confirmed by hemolytic assay. According to ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS), 144 proteins were identified in C3 among which the majority belonged to Gram negative bacteria (45.8%). Altogether, our results will help to develop novel, cost-effective, non-toxic and highly efficient antibacterial medicines from natural sources against antibiotic resistant infections.
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
- Anti-Bacterial Agents pharmacology MeSH
- Animals, Wild microbiology MeSH
- Ecosystem MeSH
- Virulence Factors genetics MeSH
- Blood Coagulation MeSH
- Methicillin pharmacology MeSH
- Molecular Epidemiology MeSH
- Nose microbiology MeSH
- Rats, Sprague-Dawley MeSH
- Staphylococcal Infections epidemiology veterinary MeSH
- Staphylococcus aureus drug effects genetics isolation & purification MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Czech Republic MeSH
- Germany 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
- Anti-Bacterial Agents pharmacology MeSH
- Bacterial Proteins genetics MeSH
- Bacterial Toxins genetics MeSH
- Exotoxins genetics MeSH
- Farms MeSH
- Goats MeSH
- Leukocidins genetics MeSH
- Methicillin-Resistant Staphylococcus aureus genetics isolation & purification MeSH
- Methicillin pharmacology MeSH
- Dairying MeSH
- Milk microbiology MeSH
- Multilocus Sequence Typing veterinary MeSH
- Sheep MeSH
- Methicillin Resistance * MeSH
- Cattle MeSH
- Staphylococcal Infections epidemiology microbiology veterinary MeSH
- Bacterial Typing Techniques veterinary MeSH
- Animals MeSH
- Check Tag
- Cattle MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Czech Republic MeSH
OBJECTIVES: Staphylococcus aureus (SA) represents one of the most important microorganism that is part of the normal microflora of humans, but in certain conditions can cause very serious infections. Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for a wide spectrum of nosocomial and community associated infections worldwide. The aim of this study was to determine community acquired MRSA (CA-MRSA), as well as the frequency of Panton-Valentine leukocidin (PVL) genes and staphylococcal cassette chromosome mec (SCCmec) types in isolates obtained from outpatients in the region of 700,000 people (Canton Sarajevo, Bosnia and Herzegovina) Methods: Our investigation included phenotypic and genotypic markers such as antimicrobial resistance, pulsed-field gel electrophoresis (PFGE), SCC typing, and PVL detection. RESULTS: Antimicrobial susceptibility: all MRSA isolates were resistant to the β-lactam antibiotics tested, and all isolates were susceptible to trimethoprim sulphamethoxazole, rifampicin, fusidic acid, linezolid, and vancomycin. After the PFGE analysis, the isolates were grouped into five similarity groups: A-E. The largest number of isolates belonged to one of two groups: C - 60% and D - 27%. In both groups C and D, SCCmec type IV was predominant (60% and 88.8%, respectively). A total of 24% of the isolates had positive expression of PVL genes, while 76% showed a statistically significantly greater negative expression of PVL genes. CONCLUSIONS: Using combination techniques, we were able to investigate the origin and genetic background of the strains. PFGE analysis revealed two large, genetically related groups of strains consisting of 87 isolates. Our results suggest failure to apply the screening policy, and a lack of knowledge about multiresistant MRSA strains. This study showed the local epidemiological situation which should be the basis of antimicrobial empiric therapy for non-hospitalized patients.
- MeSH
- Anti-Bacterial Agents therapeutic use MeSH
- Bacterial Proteins MeSH
- Bacterial Toxins genetics MeSH
- Chromosomes MeSH
- Exotoxins genetics MeSH
- Community-Acquired Infections epidemiology microbiology MeSH
- Leukocidins genetics MeSH
- Humans MeSH
- Methicillin-Resistant Staphylococcus aureus drug effects genetics isolation & purification MeSH
- Methicillin MeSH
- Microbial Sensitivity Tests MeSH
- Penicillin-Binding Proteins MeSH
- Staphylococcal Infections epidemiology microbiology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Bosnia and Herzegovina 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
- Drug Resistance, Bacterial MeSH
- Bacteriophages genetics MeSH
- Genome Size MeSH
- Genome, Viral MeSH
- Genomics MeSH
- Polymorphism, Single Nucleotide MeSH
- Methicillin pharmacology MeSH
- Mutation * MeSH
- Staphylococcus aureus growth & development virology MeSH
- Base Composition MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Keywords
- Staphylococcus pseudintermedius, MLSB rezistence,
- MeSH
- Drug Resistance, Bacterial * MeSH
- Virulence Factors * genetics classification MeSH
- Genotype MeSH
- Methicillin MeSH
- Microbial Sensitivity Tests methods MeSH
- Drug Resistance, Multiple, Bacterial MeSH
- Multiplex Polymerase Chain Reaction methods MeSH
- Dogs MeSH
- Staphylococcal Skin Infections * microbiology MeSH
- Staphylococcal Infections microbiology MeSH
- Staphylococcus * genetics classification pathogenicity MeSH
- Virulence genetics MeSH
- Animals MeSH
- Check Tag
- Dogs MeSH
- Animals MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Czech Republic 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
- Anti-Bacterial Agents chemistry pharmacology MeSH
- Genistein pharmacology MeSH
- Gram-Negative Bacteria drug effects MeSH
- Isoflavones chemistry pharmacology MeSH
- Humans MeSH
- Methicillin pharmacology MeSH
- Microbial Sensitivity Tests MeSH
- Plant Extracts pharmacology MeSH
- Staphylococcus aureus drug effects MeSH
- Structure-Activity Relationship MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
