Long-term efficacy of mupirocin in the prevention of infections with meticillin-resistant Staphylococcus aureus in a gastroenterology unit.

The long-term efficacy (55 months) of eradication of nasal carriage of meticillin-resistant Staphylococcus aureus (MRSA) by mupirocin was assessed for MRSA infections in a gastroenterology unit receiving patients for long hospital stays. In total, 2242 patients were included in the study; 92% had been hospitalized in another hospital before admission to the study department, 64% had chronic liver diseases (LD), 25% had miscellaneous medical conditions and 11% were admitted following gastroenterological surgery. Three consecutive periods were considered in the analysis. Nasal carriage at admission was similar in all three periods (10.9 vs 7.5 vs 8.6% in Periods 1, 2 and 3, respectively), while acquired nasal carriage decreased in the whole population (14.3 vs 16.2 vs 10.2% in Periods 1, 2 and 3, respectively, P=0.006) and in LD patients (15.8 vs 18.7 vs 11.9% in Periods 1, 2 and 3, respectively, P=0.018). The incidence of MRSA infections (N per total number of hospitalization-days) was 1.41 per 1000 in the year before initiation of eradication, 1.40 in Period 1, 0.74 in Period 2 and 0.59 in Period 3 (P=0.022). The incidence of MRSA infections among patients was 7.0% in Period 1, 3.7% in Period 2 and 3.1% in Period 3 in LD patients (P=0.0062). The corresponding figures were 5.5, 3.0 and 2.4% for the whole population (P=0.0024). The mortality caused by MRSA was 0.31, 0.19 and 0.13% (P=0.035) in Periods 1, 2 and 3, respectively. The numbers of resistant strains among those acquired during hospitalization were 12 in Period 1, four in Period 2 and six in Period 3. Long-term intranasal mupirocin treatment in MRSA carrier patients with long hospital stay is associated with a decrease in acquired carriage and MRSA infections, while resistance of the strains to mupirocin does not increase provided that colonized patients are only treated once.