Surveillance for mupirocin resistance following introduction of routine peri-operative prophylaxis with nasal mupirocin
Introduction
Endemic and epidemic spread of methicillin-resistant Staphylococcus aureus (MRSA) has increased interest in the use of targeted antimicrobial prophylaxis notably in the peri-operative period. The authors recently described the successful use of a five-day peri-operative prophylaxis regimen using nasal mupirocin and topical triclosan (PPNMTT) to prevent MRSA infection in patients undergoing orthopaedic surgery.1 Studies have highlighted the potential use of nasal mupirocin prophylaxis to prevent surgical site infections, notably in patients undergoing cardiothoracic surgery2, 3, 4 and possibly upper gastrointestinal surgery.5 A recent report also claimed efficacy for this approach in orthopaedic surgery.6 However, a placebo-controlled study of nasal mupirocin prophylaxis in patients undergoing orthopaedic prosthetic implant surgery found a reduction in S. aureus nasal carriage but no effect on the incidence of surgical site infections.7
It is important to monitor for emergence of mupirocin resistance, particularly when it is used for prolonged periods.8 Indeed, experience has led to the belief that long-term mupirocin usage is invariably accompanied by the emergence of resistance. However, there is a paucity of long-term data about the emergence of mupirocin resistance in units using short-term mupirocin-based prophylaxis. Therefore, the authors performed repeated point-prevalence surveillance for four years to determine whether mupirocin resistance has emerged in two surgical units using empirical, short-term, peri-operative prophylaxis with nasal mupirocin.
Section snippets
Patients and surveillance periods
From April 1999, patients undergoing orthopaedic surgery involving insertion of metal prostheses and/or fixation in three hospitals within Leeds Teaching Hospitals Trust received peri-operative prophylaxis with nasal mupirocin for five days (i.e. from day −1 to day +4), and a shower or bath with 2% v/v triclosan (Aquasept) on the day of (or night before) surgery (henceforth referred to as PPNMT). Information leaflets were given to staff and patients, and teaching was given to staff. This
Results
Of 593, 139 and 206 nasal screening swabs (taken after PPNMTT was commenced) from orthopaedic, vascular and control patients, 28%, 24% and 48% (orthopaedic/vascular vs control patients, chi-squared P<0.001) yielded S. aureus isolates, respectively, and 12%, 11% and 30% of the screening swabs were MRSA positive, respectively (orthopaedic/vascular vs control patients, chi-squared P<0.001). Of the S. aureus nasal screening isolates from orthopaedic/vascular patients (‘mupirocin-exposed’) and
Discussion
High-level mupirocin resistance results from acquisition of mupA, which encodes a resistant variant of isoleucyl-tRNA synthetase, the target enzyme for mupirocin. There is evidence that mupA may be transferable in vivo from coagulase-negative staphylococci to S. aureus.11 Thus, long-term exposure of skin commensal staphylococci (or S. aureus) to mupirocin, for example during prolonged or repeated topical application to prevent catheter exit site infection, may subsequently lead to high-level
References (18)
- et al.
Use of perioperative mupirocin to prevent methicillin-resistant Staphylococcus aureus (MRSA) orthopaedic surgical site infections
J Hosp Infect
(2003) - et al.
Surgical site infections in cardiac surgery: an 11-year perspective
Am J Infect Control
(2004) - et al.
Decrease in Staphylococcus aureus surgical-site infection rates after orthopaedic surgery after intranasal mupirocin ointment
J Hosp Infect
(2004) Phage-typing of Staphylococcus aureus
- et al.
Reduction of surgical-site infections in cardiothoracic surgery by elimination of nasal carriage of Staphylococcus aureus
Infect Control Hosp Epidemiol
(1996) - et al.
Intranasal mupirocin reduces sternal wound infection after open heart surgery in diabetics and nondiabetics
Ann Thorac Surg
(2001) - et al.
Preoperative intranasal mupirocin ointment significantly reduces postoperative infection with Staphylococcus aureus in patients undergoing upper gastrointestinal surgery
Surg Today
(2000) - et al.
Surgical site infections in orthopedic surgery: the effect of mupirocin nasal ointment in a double-blind, randomized, placebo-controlled study
Clin Infect Dis
(2002) - et al.
Development of mupirocin resistance among methicillin-resistant Staphylococcus aureus after widespread use of nasal mupirocin ointment
Infect Control Hosp Epidemiol
(1996)