title: Enhancement of antistaphylococcal activities of six antimicrobials against sasG-negative methicillin-susceptible Staphylococcus aureus: an in vitro biofilm model.
abstract: This study was designed to evaluate antimicrobial activities against methicillin-susceptible Staphylococcus aureus in both sessile and planktonic forms and to detect genes associated with this biofilm phenotype. Minimal biofilm inhibition and eradication concentrations (MBIC and MBEC, respectively) were determined by an in vitro biofilm model, and icaA, atlA, and sasG genes were detected by polymerase chain reaction. Vancomycin and tigecycline presented better biofilm inhibitory activity (MBIC range: 4-8 μg/mL) (P ≤ 0.05) and lower MBEC/MIC ratios (P ≤ 0.001) than other antimicrobials. All isolates harbored icaA and atlA, whereas sasG was present only in strong biofilm formers (P ≤ 0.05). Interestingly, antimicrobial activities against sasG- weak biofilm formers were significantly higher than those against sasG+ strong biofilm formers (P ≤ 0.05), demonstrating that number of cells in a biofilm matrix affected the antimicrobial activity, which was also variable, and might be associated with specific genetic determinants. To our knowledge, this was the first study reporting the presence of sasG in clinical isolates of S. aureus in South America.
authors: Health Sciences Post-Graduate Program, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil. kelicrisr@gmail.com
authors: Keli Cristine
authors: KC
authors: Reiter
authors: Bárbara
authors: B
authors: Villa
authors: Thiago Galvão
authors: TG
authors: da Silva Paim
authors: Gustavo Enck
authors: GE
authors: Sambrano
authors: Caio Fernando
authors: CF
authors: de Oliveira
authors: Pedro Alves
authors: PA
authors: d'Azevedo
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000382:microbiology; D001426:Bacterial Proteins / Q000235:genetics*; D018441:Biofilms / Q000187:drug effects*; D001938:Brazil; D055499:Catheter-Related Infections / Q000382:microbiology; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D008911:Minocycline / Q000031:analogs & derivatives / Q000494:pharmacology; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D000078304:Tigecycline; D014640:Vancomycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D008565:Membrane Proteins; C524374:SasG protein, Staphylococcus aureus; D014640:Vancomycin; D000078304:Tigecycline; D008911:Minocycline