Association of biofilm formation and methicillin-resistance with accessory gene regulator (agr) loci in Greek Staphylococcus aureus clones

Ikonomidis, Alexandros; Vasdeki, Afroditi; Kristo, Ioulia; Maniatis, Antonios N.; Tsakris, Athanassios; Malizos, Konstantinos N.; Pournaras, Spyros

doi:10.1016/j.micpath.2009.09.011

Cited by 25 publications

(20 citation statements)

References 14 publications

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“…Cafiso et al () and Post et al () have reported that isolates of agr II tend to be strong biofilm producers, while agr I isolates were described as weak biofilm producers. In contrast, our data indicates that many isolates of agr I had strong biofilm formation ability, which is in agreement with the results by Ikonomidis et al () and Melchior et al (). This difference may be partly related to the geographic origin or isolate source.…”

Section: Discussionsupporting

confidence: 94%

Biofilm formation and antibiotic resistance pattern of dominant Staphylococcus aureus clonal lineages in China

Song

Zhang

et al. 2016

Journal of Food Safety

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Biofilm formation usually increases antimicrobial resistance capacity of Staphylococcus aureus, which poses considerable challenges to successful eradication of staphylococcal infections. Very little is known about the biofilm-forming capacity and antibiotic resistance pattern of dominant S. aureus clonal lineages in China. In this study, the disk diffusion method and the microtiter plate assay were, respectively, performed to determine the antibiotic resistance and biofilm-forming capacity of 84 different S. aureus isolates belonging to 10 dominant clonal lineages in China. It was shown that isolates of different clonal lineages had obvious variations in biofilm-forming capacity. Resistance to individual antibacterial agents was most frequently observed to erythromycin (72.6%) and azithromycin (72.6%).Then, all tested isolates were further screened for the presence of 16 resistance genes by polymerase chain reaction (PCR), and no significant correlation was found between clonal lineage and the distribution of resistance genes. Overall, our results indicate that biofilm producers of S. aureus have a greater likelihood to carry more antibiotic resistance genes than non-biofilm producers (p < .01), further implying that biofilm may promote the dissemination of antibiotic resistance determinants. Practical applicationsStaphylococcus aureus is the leading cause of nosocomial infections and often associated with food poisoning worldwide. Biofilm formation of S. aureus influences the efficacy of antimicrobial therapy and promotes the persistence of infections; however, the knowledge about biofilm formation capacity of isolates belonging to different clonal lineages is little. Therefore, this study on biofilm formation capacity and antibiotic resistance pattern of dominant S. aureus clonal lineages could help to fix this information gap. K E Y W O R D Sagr type, antibiotic resistance, biofilm, clonal complex, Staphylococcus aureus

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Section: Discussionsupporting

confidence: 94%

Biofilm formation and antibiotic resistance pattern of dominant Staphylococcus aureus clonal lineages in China

Song

Zhang

et al. 2016

Journal of Food Safety

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“…In addition, typically of agr type I strains, the majority of our isolates did not produce biofilm in bovine milk serum (Ikonomidis et al . ; Melchior et al . ).…”

Section: Resultsmentioning

confidence: 99%

Genotypic and phenotypic characterization of methicillin-resistantStaphylococcus aureus(MRSA) isolated from milk of bovine mastitis

Bardiau

Yamazaki

Duprez

et al. 2013

Lett Appl Microbiol

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Significance and Impact of the Study: This study confirms the presence of ST398 MRSA in milk from bovine mastitis in Belgium. Moreover, the isolated MRSA strains were described for genotypic and phenotypic characteristics potentially implicated in virulence. This study highlights that Belgian bovine could be a reservoir of MRSA for human. AbstractThe aim of this study was to evaluate the presence of methicillin-resistant Staphylococcus aureus (MRSA) among a (S. aureus) collection (n = 430) isolated from milk of cows suffering from mastitis in Belgium and to compare their genotypic as well as phenotypic characteristics. Pulsed field gel electrophoresis (PFGE) and PCR-based typing techniques (MLST, spa, SCCmec, and agr typing) have been applied and supplemented by capsule serotyping, biofilm production quantification and antimicrobial susceptibility testing. Nineteen MRSA were isolated. Seven distinct ApaI PFGE patterns were observed. All isolates, except one, were identified as ST398 strains. Three spa types (t011, t567 and t108) and two SCCmec types (IV and V) were identified. All isolates belonged to agr type I and capsule type 5 and were PantonValentine leukocidin (PVL) negative. All isolates produced biofilm in TSB glc , whereas the majority did not in milk serum. Twelve resistance patterns were observed, with almost two-thirds of the isolates being resistant to at least six antibiotics, including penicillin and tetracycline. Our study confirms that the emerging ST398 LA-MRSA clone has attained Belgian cattle. With regard to genotypic and phenotypic typing, the 19 MRSA isolated in this study form a homogenous group and do not differ much from one another, neither from what has been previously described.

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“…Although we currently have no simple explanation for this observation with these particular strains, this may well reflect differences in the nature and/or the biophysical properties of the biofilm produced, ultimately affecting antibiotic bioavailability and/or expression of activity. The mechanisms of biofilm formation indeed depend on different regulatory pathways in MSSA and MRSA (52,53), with specific determinants like the agr group, polysaccharide intercellular adhesin production, and spa types being more determinant for the capacity to produce slime than the expression of microbial surface components recognizing adhesive matrix molecules (MSCRAMM) (4,54,55). The nature of the biofilm matrix can differ among strains as well, with some producing a polysaccharide-based matrix under the control of the ica locus and others producing a protein-based matrix (4).…”

Section: Discussionmentioning

confidence: 99%

A Combined Pharmacodynamic Quantitative and Qualitative Model Reveals the Potent Activity of Daptomycin and Delafloxacin against Staphylococcus aureus Biofilms

Bauer

Siala

Tulkens

et al. 2013

Antimicrob Agents Chemother

121

105

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Biofilms are associated with persistence of Staphylococcus aureus infections and therapeutic failures. Our aim was to set up a pharmacodynamic model comparing antibiotic activities against biofilms and examining in parallel their effects on viability and biofilm mass. Biofilms of S. aureus ATCC 25923 (methicillin-sensitive S. aureus [MSSA]) or ATCC 33591 (methicillin-resistant S. aureus [MRSA]) were obtained by culture in 96-well plates for 6 h/24 h. Antibiotic activities were assessed after 24/48 h of exposure to concentrations ranging from 0.5 to 512 times the MIC. Biofilm mass and bacterial viability were quantified using crystal violet and the redox indicator resazurin. Biofilms stained with Live/Dead probes were observed by using confocal microscopy. Concentration-effect curves fitted sigmoidal regressions, with a 50% reduction toward both matrix and viability obtained at sub-MIC or low multiples of MICs against young biofilms for all antibiotics tested. Against mature biofilms, maximal efficacies and potencies were reduced, with none of the antibiotics being able to completely destroy the matrix. Delafloxacin and daptomycin were the most potent, reducing viability by more than 50% at clinically achievable concentrations against both strains, as well as reducing biofilm depth, as observed in confocal microscopy. Rifampin, tigecycline, and moxifloxacin were effective against mature MRSA biofilms, while oxacillin demonstrated activity against MSSA. Fusidic acid, vancomycin, and linezolid were less potent overall. Antibiotic activity depends on biofilm maturity and bacterial strain. The pharmacodynamic model developed allows ranking of antibiotics with respect to efficacy and potency at clinically achievable concentrations and highlights the potential utility of daptomycin and delafloxacin for the treatment of biofilm-related infections.S taphylococcus aureus is a major human pathogen, implicated in both hospital-and community-acquired infections. In addition to the increase in antibiotic resistance that often limits therapeutic options, pathogenic bacteria can adapt and survive in specific microenvironments that are also associated with therapeutic failure and recurrence or persistence of infection. Among them, biofilms play a significant role in persistent infections formed on the surface of implanted medical devices and in deep tissues (1-3). Biofilms are complex aggregates of bacteria encased in an extracellular matrix made of polymeric substances like DNA, polysaccharides, teichoic acids, and proteins (4). Biofilms protect bacteria from host defense and antibiotics, allowing them to remain dormant for long periods in the host, and represent a reservoir for resistance development and for bacterial dissemination within the body. Biofilm formation and growth are finely regulated and are accompanied by metabolic changes that could also affect bacterial response to antibiotics (5).Antibiotic activity against staphylococcal biofilms has been studied in a large variety of in vitro or animal models in an attempt ...

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Association of biofilm formation and methicillin-resistance with accessory gene regulator (agr) loci in Greek Staphylococcus aureus clones

Cited by 25 publications

References 14 publications

Biofilm formation and antibiotic resistance pattern of dominant Staphylococcus aureus clonal lineages in China

Biofilm formation and antibiotic resistance pattern of dominant Staphylococcus aureus clonal lineages in China

Genotypic and phenotypic characterization of methicillin-resistantStaphylococcus aureus(MRSA) isolated from milk of bovine mastitis

A Combined Pharmacodynamic Quantitative and Qualitative Model Reveals the Potent Activity of Daptomycin and Delafloxacin against Staphylococcus aureus Biofilms

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