title: Antibiotic resistance in exopolysaccharide-forming Staphylococcus epidermidis clinical isolates from orthopaedic implant infections.
abstract: The opportunistic pathogen Staphylococcus epidermidis is able to produce biofilm and to frequently cause implant infections. In recent years, it has also exhibited an increasing antimicrobial drug resistance. Here, the resistance to a panel of 16 different antibiotics in 342 clinical strains of S. epidermidis from orthopaedic implant infections has been investigated. The isolates were pheno- and genotyped for extracellular polysaccharide production, relevant to staphylococcal biofilm formation, in order to ascertain possible associations with antibiotic resistance. Approximately 10% of the isolates were found to be sensitive to all screened antibiotics. In all, 37-38% were resistant to beta-lactams such as oxacillin and imipenem, while the resistance to penicillin, ampicillin, cefazolin, cefamandole, was consistently observed in over 80% of the strains. Erythromycin- and clindamycin- resistant strains were approximately 41% and 16%, respectively. Of the isolates, 10% was resistant to chloramphenicol, 23% to sulfamethoxazole and 26% to ciprofloxacin. Resistance to vancomycin was never observed. Interestingly, exopolysaccharide-producing strains exhibited a significantly higher prevalence in the resistance to the four aminoglycosides (gentamicin, amikacin, netilmicin, tobramycin), to sulfamethoxazole and to ciprofloxacin with respect to non-producing isolates. Moreover, multiple resistance to antibiotics was more frequent among exopolysaccharide-forming strains.
authors.affiliation: Research Unit on Implant Infections, Rizzoli Orthopaedic Institute, Via di Barbiano 1/10, 40136 Bologna, Italy. carlarenata.arciola@ior.it
authors.forename: Carla Renata
authors.initials: CR
authors.lastname: Arciola
authors.forename: Davide
authors.initials: D
authors.lastname: Campoccia
authors.forename: Simonetta
authors.initials: S
authors.lastname: Gamberini
authors.forename: Maria Elena
authors.initials: ME
authors.lastname: Donati
authors.forename: Valter
authors.initials: V
authors.lastname: Pirini
authors.forename: Livia
authors.initials: L
authors.lastname: Visai
authors.forename: Pietro
authors.initials: P
authors.lastname: Speziale
authors.forename: Lucio
authors.initials: L
authors.lastname: Montanaro
mesh_terms: D000362:Agar / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D018441:Biofilms; D002981:Clindamycin / Q000494:pharmacology; D004058:Diffusion; D024881:Drug Resistance, Bacterial; D004352:Drug Resistance, Microbial; D004917:Erythromycin / Q000494:pharmacology; D006801:Humans; D008422:Materials Testing; D008712:Methicillin / Q000737:chemistry; D009985:Orthopedics / Q000379:methods*; D011134:Polysaccharides / Q000737:chemistry* / Q000378:metabolism; D019736:Prostheses and Implants; D016459:Prosthesis-Related Infections; D013203:Staphylococcal Infections / Q000378:metabolism*; D013212:Staphylococcus epidermidis / Q000378:metabolism*; D047090:beta-Lactams / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D011134:Polysaccharides; D047090:beta-Lactams; D002981:Clindamycin; D004917:Erythromycin; D000362:Agar; D008712:Methicillin