Epidemiology ofStaphylococcus aureusin patients with cystic fibrosis

Abstract

Seven hundred and thirty-four isolates of Staphylococcus aureus, recovered from the sputum of 238 cystic fibrosis patients in six French hospitals, were characterized by esterase electrophoretic typing, capsular polysaccharide serotyping and phage typing and tested against 14 antibiotics for sensitivity. Thirty-four esterase electrophoretic types were found with a genotypic diversity coefficient of 0.91. Five hundred and forty-eight (78.7%) isolates produced capsular polysaccharide and 350 (50.3%) were type 8. Four hundred and sixty isolates (66.6%) were phage typable and 202 (28.2%) were lysed by group III bacteriophages. No esterase electrophoretic type, capsular type or phage type was specific to cystic fibrosis. Isolates belonged to a wide range of types, similar to strains acquired outside hospitals. Eighty-five patients had three or more consecutive isolates over at least 6 months. The ability of S. aureus to persist for long periods of time has been demonstrated in 73% of them. Methicillin-resistance was encountered among 73 strains (9.8%) which were also multiresistant. Two hundred and eighty-nine (39.9%) strains were sensitive to all antibiotics tested except to penicillin. Pristinamycin and co-trimoxazole were the most effective antibiotics. These results could contribute to the elaboration of a rational approach to the prophylaxis and therapy of respiratory staphylococcal infections in cystic fibrosis patients.

Genetic Relationship between Methicillin-Sensitive and Methicillin-Resistant Staphylococcus aureus Strains from France and from International Sources: Delineation of Genomic Groups

“…Although some of these groups were related, such as groups 7 to 11 and groups 15 and 16, the degree of interrelatedness was often very low (only 15%). These results are in agreement with previous estimates of genetic diversity (3,6,23); MSSA strains are polymorphic but are distributed in a limited number of major phylogenic branches. In contrast, MRSA strains were found to be clustered in a smaller number of genomic groups.…”

“…A total of 271 strains of S. aureus originating from diverse geographical origins were examined (Table 1). Two hundred twenty-six of the strains came from collections that have previously been analyzed by antibiotic typing, esterase electrophoretic typing, and phage typing (3)(4)(5)(6)(7)27). Forty-five new strains were examined.…”

“…The strains were selected according to their susceptibilities to methicillin and according to their geographical origins to maximize diversity. The strains were also selected to represent the most frequently encountered esterase electrophoretic types, as described in previous studies (4,6). One hundred sixty-two strains were recovered from French hospitals between 1980 and 1998, and 109 strains were recovered from 20 other countries.…”

“…A high degree of diversity has been observed among methicillin-sensitive S. aureus (MSSA) strains (3,6,10). However, Schlichting et al (27) noticed that epidemiologically unrelated MSSA strains with similar PFGE patterns were found in different geographical regions, suggesting that some genotypes are ubiquitous.…”

Regulation of Staphylococcus aureus Type 5 and Type 8 Capsular Polysaccharides by CO 2

“…Several extracellular and cell surface-bound components act as virulence factors in S. aureus, including capsular polysaccharides (CPs) (23,30). Although S. aureus strains can produce 11 serologically distinct CPs (16,29), the majority of clinical isolates of this pathogen have been described as CP5 or CP8 positive (1,3,4,14). Previously, however, we showed that S. aureus strains producing CP5 (12) or CP8 (22) in vitro lack these polysaccharides when directly examined by immunofluorescence microscopy of thin airway sections from CF patients.…”