Preventing surgical-site infections in nasal carriers of Staphylococcus aureus.

BACKGROUND: Nasal carriers of Staphylococcus aureus are at increased risk for health care-associated infections with this organism. Decolonization of nasal and extranasal sites on hospital admission may reduce this risk. METHODS: In a randomized, double-blind, placebo-controlled, multicenter trial, we assessed whether rapid identification of S. aureus nasal carriers by means of a real-time polymerase-chain-reaction (PCR) assay, followed by treatment with mupirocin nasal ointment and chlorhexidine soap, reduces the risk of hospital-associated S. aureus infection. RESULTS: From October 2005 through June 2007, a total of 6771 patients were screened on admission. A total of 1270 nasal swabs from 1251 patients were positive for S. aureus. We enrolled 917 of these patients in the intention-to-treat analysis, of whom 808 (88.1%) underwent a surgical procedure. All the S. aureus strains identified on PCR assay were susceptible to methicillin and mupirocin. The rate of S. aureus infection was 3.4% (17 of 504 patients) in the mupirocin-chlorhexidine group, as compared with 7.7% (32 of 413 patients) in the placebo group (relative risk of infection, 0.42; 95% confidence interval [CI], 0.23 to 0.75). The effect of mupirocin-chlorhexidine treatment was most pronounced for deep surgical-site infections (relative risk, 0.21; 95% CI, 0.07 to 0.62). There was no significant difference in all-cause in-hospital mortality between the two groups. The time to the onset of nosocomial infection was shorter in the placebo group than in the mupirocin-chlorhexidine group (P=0.005). CONCLUSIONS: The number of surgical-site S. aureus infections acquired in the hospital can be reduced by rapid screening and decolonizing of nasal carriers of S. aureus on admission. (Current Controlled Trials number, ISRCTN56186788.)

Highly resistant microorganisms in a teaching hospital: the role of horizontal spread in a setting of endemicity.

OBJECTIVE: To determine the incidence density of highly resistant organisms (HROs) and the relative contribution of horizontal spread in a setting of endemicity. METHODS: Prospective surveillance was performed among hospitalized patients during an 18-month period. Enterobacteriaceae, nonfermentative gram-negative bacilli, Staphylococcus aureus, Streptococcus pneumoniae, and Enterococcus faecium--all considered highly resistant, according to Dutch guidelines--were included. Epidemiological linkage and nosocomial transmission were determined on the basis of molecular typing and hospital admission data. RESULTS: From 119 patients, we recovered a total of 170 unique HRO isolates, as follows: Escherichia coli, 96 isolates; Klebsiella species, 11 isolates; Enterobacter species, 8 isolates; Proteus species, 9 isolates; Citrobacter species, 5 isolates; Pseudomonas species, 5 isolates; Acinetobacter species, 3 isolates; Morganella species, 2 isolates; Salmonella species, 1 isolate; Serratia species, 1 isolate; S. pneumoniae, 20 isolates; and S. aureus, 9 isolates. No vancomycin-resistant E. faecium was found. The incidence density was 4.3 HRO isolates per 10,000 patient-days. The majority of HRO isolates were unique, and nosocomial transmission was observed 4 times for highly resistant gram-negative bacilli (case reproduction rate, 0.05) and 4 times for penicillin-nonsusceptible S. pneumoniae (case reproduction rate, 0.29). A stay on the intensive care unit was the main determinant for the recovery of an HRO. CONCLUSION: Nosocomial transmission of HROs was observed 8 times during the 18-month period. The intensive care unit was identified as the main reservoir of horizontal spread of HROs. This study shows that nosocomial transmission of HROs is largely preventable using transmission precautions.

Appropriateness of antimicrobial therapy measured by repeated prevalence surveys.

Prudent use of antibiotics is mandatory to control antibiotic resistance. The objective of this study was to determine if prevalence surveys are useful tools to determine the appropriateness of antimicrobial therapy (AMT) and determinants of inappropriate AMT. The study was performed in a 1,350-bed teaching hospital including all medical specialties. Six consecutive 1-day prevalence surveys of in-patients were performed twice yearly from 2001 to 2004. Data on the demographics, infections, and AMT were gathered. The appropriateness of AMT was assessed according to a standardized algorithm based on the local AMT prescription guidelines. On average, 684 patients were included in each survey (total, 4,105). The use of AMT as determined in the prevalence survey corresponded to the annual data from the pharmacy department. Nine hundred thirty-eight (22.9%) of the patients received AMT, and in 351 (37.4%) of these patients AMT was inappropriate. Only 25 (0.6%) patients did not receive AMT, although it was indicated. After multivariate analysis, the use of quinolones was the only statistically significant variable associated with inappropriate use. Prevalence surveys proved to be useful tools to judge the appropriateness of AMT and to identify determinants of inappropriate use. This study shows that in a setting with a low use of AMT, there are few patients who inadvertently do not receive AMT. On the other hand, a substantial number of the patients are treated inappropriate.