Antibiotic susceptibility among Staphylococcus epidermidis isolated from prosthetic joint infections with special focus on rifampicin and variability of the rpoB gene

Abstract

Staphylococcus epidermidis is the most important pathogen in infections related to implanted foreign materials, especially prosthetic joint infections (PJIs). The aim of this study was to investigate the antimicrobial activities of 16 antibiotics against S. epidermidis isolated from PJIs, with special focus on rifampicin and rpoB variability. Ninety-one per cent of the isolates were multiresistant (i.e. resistant to members of more than three classes of antibiotics). Thirty-nine per cent were resistant to rifampicin, associated with one or two single-nucleotide polymorphisms (SNPs) in rpoB. Using IsoSensitest agar with supplements, 61% were resistant to oxacillin, and using Mueller-Hinton II agar with supplement, 84% were resistant. Using the Etest, 58% were resistant to cefoxitin, and using the disk diffusion test, 91% were resistant. The mecA gene was detected in 85% of the isolates. Regarding recently available antibiotics, all isolates were susceptible to tigecycline and linezolid, and 97% were susceptible to daptomycin. In addition, two novel antibiotics, dalbavancin and ceftobiprole, were tested, although not yet available for routine use. The MIC(50) and MIC(90) values of these novel antibiotics were 0.032 and 0.047 mg/L and 0.5 and 1.5 mg/L, respectively. Among the other antibiotics, the rates of resistance varied between 0% (vancomycin) and 82% (trimethoprim-sulphamethoxazole). S. epidermidis strains causing PJIs often show multiresistance, including resistance to rifampicin, which is mainly caused by one or two SNPs. Some of the newer antimicrobial agents may provide alternatives for monotherapy or combination therapy with rifampicin. Detection of mecA is necessary before initiating treatment of infections due to S. epidermidis when it displays intermediate susceptibility to cefoxitin.

Biofilm Producing Staphylococcus epidermidis Strains Isolated From Clinical Samples in Tehran, Iran

“…The prevalence of erythromycin-resistant strains was significantly lower in other studies (30)(31)(32). On the other hand, we found that 10 biofilm and non-biofilm-producing strains showed susceptibility to all tested antibiotics except for penicillin; these findings are consistent with our previous reports for S. aureus strains (17,(33)(34)(35)(36)(37)(38).…”

Increased Temperature Enhances the Antimicrobial Effects of Daptomycin, Vancomycin, Tigecycline, Fosfomycin, and Cefamandole on Staphylococcal Biofilms

“…Rifampin, which is probably the single most important drug currently used against biofilm infections of arthroplasties (49), was not investigated in the present study because of the existence of many experimental and clinical data (50). Although rifampin is very active against bacterial and staphylococcal biofilms in particular, resistance to rifampin is increasing in many organisms and not only staphylococci (22,28). The question is how heat can be applied topically and used for a long period without risking thermal burns.…”

Prevenção da formação de biofilmes em marcapassos artificiais: é viável?

“…(17) Rifampicin is considered to be the antimicrobial agent of choice for the treatment of CIED, since previous studies have shown that, in combination with other antimicrobials (usually linezolid or teicoplanin), rifampicin is able to prevent vascular infections caused by methicillin-resistant S. aureus and S. epidermidis. (11,13,18) Still using rifampicin, the AIGIS (RX)® product was developed to provide a novel approach by creating an antibiotic mesh in which a variety of devices can be implanted to reduce the development of infections in cardiac implants. This product combines rifampicin and minocycline and has been effective in preventing cardiac device colonization and clinical infections by S. aureus.…”