National survey of molecular epidemiology of Staphylococcus aureus colonization in Belgian cystic fibrosis patients.

OBJECTIVES: Epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) is poorly defined in cystic fibrosis (CF) patients, and S. aureus detection may be hampered by the presence of small colony variants (SCVs). We conducted a multicentre survey to determine the prevalence of S. aureus and MRSA colonization in Belgian CF patients and characterize the phenotype and clonal distribution of their staphylococcal strains. METHODS: S. aureus isolated from CF patients attending nine CF centres were collected. Oxacillin resistance was detected by oxacillin agar screen and mecA PCR. Antibiotic susceptibility was tested by microdilution. MRSA strains were genotyped by PFGE and SCCmec typing and compared with hospital-associated MRSA strains. RESULTS: Laboratories used a diversity of sputum culture procedures, many of which appeared substandard. S. aureus was isolated from 275/627 (44%) CF patients (20% to 72% by centre). The prevalence of SCV colonization was 4%, but SCVs were almost exclusively recovered from patients in two centres performing an SCV search. Phenotypically, 14% of S. aureus isolates were oxacillin-resistant: 79% carried mecA and 19% were SCVs lacking mecA. The mean prevalence of 'true' MRSA colonization was 5% (0% to 17% by centre). By PFGE typing, 67% of CF-associated MRSA were related to five epidemic clones widespread in Belgian hospitals. CONCLUSIONS: This first survey of S. aureus colonization in the Belgian CF population indicated a diversity in local prevalence rates and in proportion of oxacillin-resistant and SCV phenotypes, probably related to variation in bacteriological methods. These findings underscore the need for standard S. aureus detection methods and MRSA control policies in Belgian CF centres.

Evaluation of the ProSpecT Microplate Assay for detection of Campylobacter: a routine laboratory perspective.

OBJECTIVES: To evaluate the use of the new enzyme-linked immunosorbent assay, the ProSpecT Campylobacter Microplate Assay (Alexon-Trend, Minneapolis, MN, USA), which allows 2-h detection of both Campylobacter jejuni and Campylobacter coli antigen directly in stool specimens. METHODS: Over 4 months, all stool samples preserved in Cary-Blair medium, or fresh specimens, from non-hospitalized children and HIV-infected patients (adults and children), submitted to our laboratory were evaluated with the ProSpecT Campylobacter Microplate Assay. Results were compared with those obtained by routine culture methods using both a specific medium and a filtration method for the recovery of Campylobacter spp. RESULTS: Of the 1205 stool specimens cultured, 101 were found to be positive for either C. jejuni or C. coli, giving an overall recovery rate of 8.38%. Ninety samples were positive by both culture and ProSpecT Campylobacter Microplate Assay, and 11 were positive by culture only, giving a sensitivity of 89.1%. In addition, of 1104 samples negative by culture, 25 were initially positive by ProSpecT Campylobacter Microplate Assay. We found no cross-reaction with other bacterial enteropathogens isolated from stool specimens. These results thus confirm a high specificity (97.7%) for both C. jejuni and C. coli. The positive and negative predictive values found were 78.3% and 99%, respectively. There was no statistically significant difference in sensitivity and specificity if the stool was fresh or preserved with Cary-Blair medium. CONCLUSION: These data suggest that the ProSpecT Campylobacter Microplate Assay is a rapid and easy-to-use test for the detection of both C. jejuni and C. coli in stool specimens. It could be used for patients for whom early antibiotic therapy is needed or for epidemiologic studies.

[Induced expectoration or endoscopic samples in case of bronchopulmonary infection?]. / Expectorations induites ou prélèvements endoscopiques en cas d'infection bronchopulmonaire?

The aim of this study was to compare induced sputum versus bronchoscopy in a non selected population. An induced sputum and a bronchoscopy with aspiration of secretions and bronchoalveolar lavage (BAL) were proposed to 30 patients with suspected lower respiratory tract infection, including 14 subjects with AIDS. Induced sputum failed in 3 patients, while endoscopy could not be performed (contra-indication, refusal or failure due to lack of cooperation) in 7 patients; a technical failure for BAL was observed in 3/23 cases. Contamination by oral germs was significantly less frequent with BAL (4/20) than with aspiration (15/23) or induced sputum (17/27). A relevant pathogen was cultured from induced sputum in 7/27 cases (3 mycobacteria, 4 usual pathogens) from aspiration in 3/23 cases (one mycobacterium, 2 usual pathogens) and from BAL in 4/20 cases (one mycobacterium, 3 usual pathogens). These results suggest that induced sputum is a promising method when difficulties in performing bronchoscopy are expected (severe respiratory insufficiency, psychiatric disease, lack of cooperation).