Decolonization is an evidence-based patient safety practice with the goal of lowering the microbial bio-burden on patient body sites to reduce the risk of infection from endogenous colonization during surgery.
Nasal decolonization has become an important strategy for reducing surgical site infections (SSIs) due to Staphylococcus aureus (S. aureus). Data from the National Healthcare Safety Network (NHSN) for 2014 reports that S. aureus is the primary pathogen responsible for SSIs, with 42.6 percent of S. aureus SSIs caused by methicillin-resistant S. aureus (MRSA).
The gold standard for nasal decolonization has been mupirocin. However, selective pressure has led to mupirocin-resistant strains of S. aureus and treatment failures. Patient compliance and satisfaction has been suboptimal, in part due to the need for multiple applications prior to surgery. As part of an overall approach to patient safety and antibiotic stewardship, investigators have looked to antiseptics, such as povidone-iodine (PVP-I), as alternatives.
An estimated 157,500 SSIs resulting in more than 8,000 deaths occur annually in the United States healthcare system. The estimated excess length of hospital stay (LOS) for these infections is 11 days, with a cost of $20,785. If MRSA is the causative pathogen, the LOS and cost increases to 23 days and $42,300, respectively.
The anterior nares are the primary reservoir for S. aureus carriage and approximately 20-30 percent of healthy individuals are persistently colonized. Approximately 1-3 percent of healthy adults are colonized with MRSA; higher carriage rates have been reported among hospitalized and long-term care patients.
As S. aureus carriers are two to nine times more likely than non-carriers to have SSIs, perioperative nasal decolonization has been extensively studied as an SSI prevention strategy. The introduction in the mid-1980s of mupirocin calcium ointment led to its widespread use as the decolonization agent of choice for preventing S. aureus infection and transmission.
Mupirocin has excellent in vitro activity against staphylococci and most streptococci, is rapidly metabolized, and has minimal side-effects. “The Mupirocin and the Risk of Staphylococcus aureus (MARS) Study” found that among the patients with nasal carriage of S. aureus, 4.0 percent of those who received mupirocin had nosocomial S. aureus infections compared with 7.7 percent of those who received placebo (OR 0.49; P=0.02).
The orthopedic and cardiothoracic surgical communities have widely adopted mupirocin decolonization protocols. A systematic review of 19 studies found a range of SSI reduction from 29-57 percent in total SSIs for those using mupirocin alone and 13-81 percent in total SSIs, 56-200 percent reductions in S. aureus SSIs, and 29-100 percent reductions in MRSA SSIs for those using mupirocin and chlorhexidine.
A trial involving cardiac surgery patients with an intervention of pre-operative nasal screening for MSSA and MRSA, decolonization of carriers with mupirocin twice daily and chlorhexidine daily bathing for 5 days, and modification of prophylactic antibiotics to vancomycin and cefazolin for MRSA carriers, found a 42 percent reduction in SSIs.
In the late 1990s, mupirocin resistance began to emerge. In a large public teaching hospital that implemented universal decolonization with nasal mupirocin as an adjunct to infection control measures to address an endemic MRSA problem, mupirocin resistance among MRSA isolates increased from 2.7 percent to 65 percent over a 3-year period.
More recent surveillance studies have reported mupirocin-resistant (MupR) MRSA strains in up to 13 percent of surgical ICU patients in the absence of routine use of mupirocin and 23.7 percent MupR among MRSA clinical isolates in a facility where mupirocin was routinely used to decolonize MRSA-positive patients.
A strong association has been found between prior mupirocin use and subsequent mupirocin-resistant in MRSA. Currently, mupirocin susceptibility testing is infrequently performed, and the prevalence of MupR MRSA strains is unknown in many clinical settings.
Concern has also been cited regarding suboptimal patient compliance with the mupirocin regimen of twice daily application for five days and overall patient satisfaction. These concerns have led to the use of antiseptics as alternative nasal decolonization agents. One such alternative, PVP-I, is gaining popularity due to its efficacy in eradicating S. aureus, safety, patient satisfaction, and cost.
Povidone-iodine (PVP-I) is a complex of polyvinylpyrrolidine and tri-iodine ions which has been used widely for cutaneous antisepsis prior to the insertion of intravascular devices and surgical procedures and for wound irrigation.
An in vitro study comparing the activity against S. aureus isolates of 5 percent PVP-I cream vs. mupirocin, found PVP-I to be bactericidal against three MupS S. aureus strains from nasal carriers, and both MupS and MupR MRSA strains after 1 minute of incubation, but mupirocin did not prevent growth after 180 minutes of incubation. These authors highlighted the rapid bactericidal activity of PVP-I compared with that of mupirocin and the importance of its activity against emerging MupR MRSA strains.
The use of PVP-I for nasal decolonization has revealed promising results. In an open-label, randomized trial of patients undergoing arthroplasty or spine fusion procedures, deep SSI rates within 90 days were compared for those individuals receiving topical 2 percent chlorhexidine wipes the night before and morning of surgery in combination with either twice daily application of nasal mupirocin ointment during the 5 days before surgery or two applications of 5 percent povidone-iodine (PVP-I) solution into each nostril within two hours of surgical incision.
An evaluation of 763 surgical procedures in the mupirocin group and 776 surgical procedures in the PVP-I group was performed. In the per-protocol analysis, S. aureus deep SSIs developed in ﬁve patients (0.7 percent) who received mupirocin and zero patients (0.00 percent) among those who received PVP-I (p = 0.03).
For patients with a preoperative S. aureus nasal culture, another nasal culture was obtained within one to three days after surgery. The proportion of postoperative negative nasal cultures was 92 percent for patients in the mupirocin group vs. 54 percent in the PVP-I group. This was expected as mupirocin was intended to eradicate colonization while PVP-I was intended only to suppress S. aureus during surgery. The conclusion: nasal PVP-I may be considered as an alternative to mupirocin in a multifaceted approach to reduce SSI.
A recent quasi-experimental, retrospective, nonrandomized trial compared a preoperative decontamination intervention — 2 percent chlorhexidine washcloths and 0.12 percent chlorhexidine oral rinse the night before and morning of surgery and the use of 5 percent PVP-I intra-nasally once the morning of surgery — to historical controls without a decontamination protocol to evaluate the impact on SSI rates for patients undergoing elective orthopedic procedures with hardware implantation. Nasal screening for S. aureus before and after decontamination was not performed.
A total of 709 patients were analyzed (344 controls and 365 patients who were decolonized) with both groups well matched for age, sex, body mass index, and co-morbidities. There was 100 percent compliance with completion of the decontamination protocol by patients in the intervention group. Rates of SSIs were signiﬁcantly lower in the intervention group than in the control group (1.1 percent versus 3.8 percent; p = 0.02).
In addition to the more than 50 percent reduction in SSI rates, adherence to and cost of a decontamination regimen is a cardinal factor for its success. It was noted that a decolonization protocol containing PVP-I instead of mupirocin could potentially dissipate concerns regarding antibiotic resistance, broaden application beyond S. aureus carriers, and result in cost-savings ($35.00 per patient for the PVP-I regimen vs. $54.00 for mupirocin and chlorhexidine).
PVP-I decolonization is a promising alternative to mupirocin for the reduction of SSIs and may promote better patient compliance. Maslow and colleagues studied patient experience with preoperative nasal decolonization. The study evaluated and compared patient experiences and satisfaction of patients randomized to receive either PVP-I or mupirocin ointment (MO) along with 2 percent chlorhexidine gluconate wipes.
Of 1679 patients interviewed, the majority felt that being an active participant in SSI prevention was a positive experience. Those assigned to receive PVP-I as nasal decolonization reported significantly fewer adverse events than the nasal MO group (P<.01).
Of patients receiving PVP-I, 3.4 percent reported an unpleasant or very unpleasant experience, compared with 38.8 percent using nasal MO (p = <.0001). Of participants in the MO group, 67 percent felt it to be somewhat or very helpful in reducing SSIs vs. 71 percent of patients receiving PVP-I (p= >.05).
Despite the shorter course of treatment for PVP-I (5 percent PVP-I nasal solution in both nostrils by staff within two hours of surgical incision vs. MO 2 percent ointment twice daily for five days preoperatively until the morning of surgery), it was perceived to be similarly effective in reducing SSI risk. In addition, 54 percent of patients reported paying out-of-pocket expenses for MO totaling as much as $115 per treatment.
The emergence of mupirocin-resistant S. aureus strains, suboptimal compliance and reduced patient satisfaction has led to the adoption of antiseptics for nasal decolonization. The most effective regimen for nasal decolonization to prevent SSIs should have proven efficacy against S. aureus, the major pathogen responsible for these infections, be easy to apply, have minimal adverse reactions, and be a positive experience for patients.
PVP-I has rapid bactericidal activity against both mupirocin-sensitive and mupirocin-resistant strains of S. aureus, has no reports of bacterial resistance, can be applied immediately prior to surgery to suppress nasal carriage during the period of risk for bacterial contamination, has high patient satisfaction scores, and is cost-effective. PVP-I offers a promising alternative to mupirocin for the prevention of SSIs.
Joan Hebden, MS, RN, CIC, FAPIC received her baccalaureate and master’s degrees from the University of Maryland School of Nursing. Her clinical background includes general medicine, oncology, and cardiothoracic intensive care.
A version of this article appears in the May/June 2018 issue of Surgical Products.