Lack of association of Staphylococcus aureus type A beta-lactamase with cefazolin combined with antimicrobial spacer placement prosthetic joint infection treatment failure.

Association of cefazolin treatment failure with type A beta-lactamase-producing Staphylococcus aureus has been suggested. The prevalence of beta-lactamase gene types among 23 methicillin-susceptible S. aureus (MSSA) isolates associated with prosthetic joint infection (PJI) treated with cefazolin was determined using polymerase chain reaction (PCR), and clinical and microbiologic outcomes were assessed. PCR revealed 4 isolates without blaZ, and 12 with type A, 2 with type B, and 5 with type C blaZ. Of 13 patients undergoing resection arthroplasty with subsequent reimplantation, all received antimicrobial spacer placement at resection with or without antimicrobial-impregnated polymethylmethacrylate at reimplantation. All 13 cases had tissue cultures at time of reimplantation that were negative for S. aureus and 11 had histopathology specimens showing no acute inflammation. Of 8 type A cases undergoing reimplantation, all prostheses remained in place at follow-up (median, 798 days; range, 32-927 days). We conclude that type A blaZ is common in MSSA PJI and that cefazolin therapy for blaZ MSSA PJI can be successful when combined with 2-stage reimplantation and local antimicrobial therapy.