It has been reported that 25% to 30% of the population has Staphylococcus colonized in their anterior nares (19). Nasal colonization has been associated with host infection and surgical site infection (SSI) of patients postoperatively. Calia et al. (20) were able to document the importance of the carrier state as a source of S. aureus wound sepsis. The authors found that 36% or 96 of 269 patients were carriers of S. aureus before a surgical procedure. The risk of wound sepsis was almost twice as great in carriers. Fifty-one of the 96 carriers harbored bacteria in their nasal cavity. Based on this premise, decolonization protocols have been established to lower the incidence of Staphylococcal surgical site infections (21).

Early protocols included the use of a single application of 2% mupirocin calcium ointment (Bactroban Nasal, GlaxoSmithKline) applied topically to the anterior nares. The studies were effective in decreasing the number of surgical site infections caused by Staphylococcus but the overall incidence of infection was unchanged. Additional studies over the ensuing decade have resulted in changes to the decolonization protocol. The current recommendations include 2% nasal mupirocin ointment for 3 to 5 days preoperatively, chlorhexidine gluconate showers, and prophylactic antibiotics that are specific for the bacteria cultured from the nares.
Antibiotics are given to patients based on this nares carriage preoperatively and for 24 hours postoperatively. For example, if methicillin-resistant Staphylococcus was cultured from the nares then vancomycin was used as a prophylactic antibiotic in addition to an antibiotic covering a broad spectrum of bacteria.

Kim et al. (22) performed a single-center study of 7,338 orthopedic patients who were asked to participate in a study to screen and treat patients preoperatively. Seven thousand nineteen or 95.7% of the patients were successfully screened. One thousand five hundred and eighty-eight (22.6%) of the group were S. aureus carriers and 309 (4.4%) of the group were identified as methicillin-resistant Staphylococcus aureus (MRSA) carriers. Patients known to carry bacteria were treated with 2% mupirocin ointment twice daily for 5 days and a shower wash with 2% chlorhexidine gluconate twotime daily for 5 days. A posttreatment nasal culture was performed to confirm eradication of the bacteria. SSI rates were compared between the study group and control patients who were followed postoperatively for 30 days. The authors reported a 59% reduction in the rate of infection (p = 0.0093) (22). One of the interesting findings included a decrease in both methicillin-resistant and methicillin-sensitive S. aureus infections using the above-described protocol. Factors that contributed to this success included a presurgical screening performed several days before surgery allowing for the complete treatment (5 days) of the patients who were carriers. In addition, bacteria-specific antibiotics could be given to patients to prevent SSI from their nasal carriage because of the preoperatively identified bacteria (e.g., vancomycin for MRSA carriers).

It has been reported that decolonization protocols including intranasal mupirocin twice daily for 5 days eradicated S. aureus infection in greater than 83% of patients in the short term (19), but the question of cost-effectiveness was raised? Courville et al. (23) performed a cost-effectiveness analysis based on a hypothetical cohort of 65-year-old patients with end-stage hip or knee arthritis. The model depicted the risk of revision surgery for a deep SSI within 1 year of the primary operation. Three scenarios were modeled including preoperative nasal screening of all patients with S. aureus colonization followed by treatment with mupirocin for positive patients, preoperative mupirocin for all patients (all strategy), and finally no screening and no treatment (no treatment strategy).

Model parameters based on previous publications and the authors’ institutional information found the relative risk of SSI from S. aureus carriers ranged from 0.6% to 1.3% and was 0.58% for noncarriers. In addition, in their institution 26% of patients were S. aureus carriers. The authors provided a sensitive analysis based on the average cost-effectiveness for the most cost-effective strategy and included data for hip and knee arthroplasty patients separately (23). The analysis demonstrated that both the treat all strategy and the screen and treat strategy for total joint using the preoperative S. aureus decolonization program with nasal mupirocin was cost-effective compared to no decolonization.

One of the limitations of the cost-effectiveness study is the exclusion of specific problems like mupirocin resistance. It is not surprising that bacteria have developed strategies to resist to mupirocin as history demonstrates that it is a natural process of bacteria. Bacteria can acquire more genetic material or mutate, but either results in resistance. A multi-institutional study by Desroches et al. (24) collected and analyzed 367 MRSA and 708 coagulase-negative Staphylococcal isolates from 37 hospitals between October 2011 and February 2012. Mupirocin resistance was identified in 2.2% of the MRSA isolates (1.4% with low-level resistance and 0.8% with high-level resistance). Mupirocin resistance was identified in 10.3% of the coagulase-negative Staphylococcal isolates. Chlorhexidine-gluconate resistance has also been identified. Fritz et al. (25) studied 1,089 patients with a skin or soft tissue infection with or without S. aureus colonization. Four hundred and eighty-three were enrolled in a decolonization protocol. At baseline, 23 of 1,089 (2.1%) carried a mupirocin-resistant S. aureus strain and 10 of 1,089 (0.9%) of the patients carried a chlorhexidine-gluconate–resistant S. aureus. Decolonization failed in all the mupirocin-resistant patients and 50% of chlorhexidine-gluconate patients.

Another alternative to the use of mupirocin to decolonize the nasal cavity is antimicrobial photodynamic therapy first reported in 2009 (26). Further studies are needed to assess the effectiveness for orthopedic surgery patients. The photodisinfection therapy procedure consists of priming the anterior nares with a 0.1% methylene blue photosensitizer solution for 30 seconds followed by a photo disinfection illumination for 120 seconds. The procedure may be performed once or twice for a total illumination time of 240 seconds with light directed toward the posterior aspect of the nares on the first illumination and toward the anterior aspect of the nares on a second illumination.