The flora of implant-based breast infections has changed over the last decade, including at our institution. A 10-year retrospective chart review was performed on 561 implant-based breast reconstructions in 378 patients performed by a single surgeon in an academic university hospital setting. Thirty-two breast infections requiring explantation of the implants occurred during those 10 years. During that time frame, a new pre-and peri-operative protocol was implemented in an effort to diminish infections. We believe that this protocol played a major role in the evolution of changing breast periprosthetic infection flora, from nearly onethird being gram-negative infections to 100% being gram-negative infections. Gram-negative antibiotic coverage should be considered in light of these evolving trends to prevent infections particularly with Serratia marcescens. This may be especially important in patients with BRCA1/2 or ATM mutations. Diabetic patients are more likely to develop Methicillin-resistant Staphylococcus aureus (MRSA) infections and preoperative MRSA decolonization is essential in these patients. Many patients have lateonset breast periprosthetic infection, the majority of which occurred after 30 days. Regular follow-up and patient education is important to provide timely treatment. Résumé La flore des infections mammaires par implant s'est modifiée depuis dix ans, y compris dans l'établissement des auteurs. Dans un hô pital universitaire, un chirurgien a procédé à une analyse rétrospective sur dix ans des dossiers de 561 reconstructions mammaires par implant réalisées chez 378 patientes. Pendant ces dix ans, 32 infections mammaires ont entraîné l'explantation des implants. Un nouveau protocole préopératoire et périopératoire aété adopté au cours de cette période, afin de réduire les infections. Les auteurs sont d'avis que ce protocole a joué un rô le majeur dans l'évolution de la flore des infections mammaires périprothétiques, qui sont passées de près du tiers à 100 % d'infections à Gram négatif. Il faudrait examiner la couverture antibiotique de ces infections à la lumière de ces tendances afin de prévenir les infections, notamment celles à Serratia marcescens. Cette décision serait particulièrement importante pour les patientes présentant des mutations BRCA1/2 ou ATM. Les patientes diabétiques sont plus susceptibles de contracter des infections à Staphylococcus aureus résistantes à la méthicilline (SARM); la décolonisation préopératoire à SARM est essentielle dans ce cas. De nombreuses patientes ont souffert d'une infection mammaire périprothétique tardive, dont la majorité s'est déclarée plus de 30 jours après l'implant. Il est important d'assurer un suivi régulier et d'éduquer les patientes pour pouvoir leur offrir un traitement au moment opportun.

Background: Perioperative administration of intravenous antibiotics is a routine part of total knee arthroplasty.  Antibiotic selection is a matter of controversy, and the potential risks and benefits associated with each antibiotic selection need to be considered.  The objective of this study is to examine the effects of routine dual antibiotic prophylaxis with both cefazolin and vancomycin on infection and renal failure after primary total knee arthroplasty (TKA) compared with cefazolin alone.Methods: We performed a retrospective review of primary TKA patients for two years before and two years after routine dual antibiotic prophylaxis was implemented at our institution. 1502 patients were included (567 cefazolin-only and 935 dual prophylaxis).  Results: 2 patients (0.4%) in the cefazolin-only group had a deep surgical site infection, compared with 13 patients (1.4%) in the dual prophylaxis group (p=0.06). 46 patients (8.1%) in the cefazolin-only group had postoperative renal failure, compared with 36 patients (3.9%) in the dual prophylaxis group (p=0.0006).Discussion and Conclusion: Our results did not support the routine use of vancomycin in primary total joint arthroplasty to decrease periprosthetic joint infection. However, we also did not see any clear harm due to renal failure in the routine use of dual antibiotic prophylaxis.