MUPIROCIN TREATMENT OF STAPHYLOCOCCUS-AUR EUS NASAL CARRIAGE AND PREVENTION OF INFECTION IN INTENSIVE-CARE UNITS - A MULTICENTER CONTROLLED-STUDY

Objective: To examine the efficacy of nasal mupirocine ointment for er adication of S. aureus nasal carriage and prevention of acquired infec tions due to S. aureus in patients hospitalised in intensive care unit s (ICU) with high endemic rate of MRSA. Design: Open sequential trial with two periods of 18 and 16 weeks, with one untreated group compared to a subsequent treated group. Setting: Five medical or polyvalent IC Us in university or university-affiliated hospitals. Patients: Consecu tive patients with ICU stay of over two days and simplified acute seve rity score of >6. Intervention: Nasal swabs were obtained on admission and every four days for the first 2 weeks of ICU stay. During the sec ond period, patients with S. aureus nasal carriage were treated with m upirocin for 5 days. Measurements and main results: S. aureus nasal ca rriage was detected in 225/546 (41%) patients followed during the firs t period, including 152 (28%) on admission and 95 (17.4%) secondarily; S. aureus infection occurred in 57 (10.4%) patients, associated in 33 (6%) with secondarily acquired nasal carriage. During the treatment p eriod, nasal carriage was detected in 159/463 patients (34.4%, p=0.03) , including 107 (23%) on admission and 59 (12.8%, p=0.04) secondarily. Mupirocin treatment resulted in eradication of nasal carriage in 78/9 5 evaluable patients treated; S. aureus infections however occurred in 35 (7.6%, p=0.12) patients, including 25 (5.4%) with secondarily acqu ired infection and nasal carriage. Methicillin-resistant strains (MRSA ) accounted for 56% and 49% of all S. aureus isolates in the two perio ds, respectively, including 32% and 33% of isolates recovered from scr eening samples on admission and 88% and 76% of isolates (p<0.001) reco vered after 4 days in the ICU. Six strains recovered during the second period had low-level resistance to mupirocin. Conclusions: In intensi ve care units where MRSA is highly endemic, screening for nasal carrie rs and their subsequent treatment with mupirocin results in limited re duction of infection rates despite marked efficacy on nasal carriage, and carries the risk of emergence of resistance to the topical agent.