Please use this identifier to cite or link to this item:http://hdl.handle.net/20.500.12105/8256
Dynamics of long-term colonization of respiratory tract by Haemophilus influenzae in cystic fibrosis patients shows a marked increase in hypermutable strains [Postprint]
Roman, Federico ISCIII | Cantón, Rafael | Perez-Vazquez, Maria Dolores ISCIII | Baquero, Fernando | Campos, Jose ISCIII
J Clin Microbiol. 2004 Apr;42(4):1450-9.
The persistence and variability of 188 Haemophilus influenzae isolates in respiratory tract of 30 cystic fibrosis (CF) patients over the course of 7 years was studied. Antibiotic susceptibility testing, DNA fingerprinting, and analysis of outer membrane protein profiles were performed on all isolates. A total of 115 distinct pulsed-field gel electrophoresis profiles were identified. Ninety percent of patients were cocolonized with two or more clones over the studied period. A third of the patients were cross-colonized with one or two H. influenzae strains; 11% of the clones persisted for 3 or more months. Biotype, outer membrane protein profiles, and resistance profiles showed variation along the studied period, even in persisting clones. Four isolates (2.1%) recovered from 3 patients were type f capsulate, with three of them belonging to the same clone. beta-Lactamase production was detected in 23.9% of isolates while 7% of the beta-lactamase-negative isolates presented diminished susceptibility to ampicillin (beta-lactamase-negative ampicillin resistance phenotype). Remarkably, 21.3% of the H. influenzae isolates presented decreased susceptibility to ciprofloxacin, which was mainly observed in persisting clones. Of the H. influenzae isolates from CF patients, 18 (14.5%) were found to be hypermutable in comparison with 1 (1.4%) from non-CF patients (P < 0.0001). Ten patients (33.3%) were colonized by hypermutable strains over the study period. A multiresistance phenotype and long-term clonal persistence were significantly associated in some cases for up to 7 years. These results suggest that H. influenzae bronchial colonization in CF patients is a dynamic process, but better-adapted clones can persist for long periods of time.
Adolescent | Adult | Anti-Bacterial Agents | Child | Child, Preschool | Cystic Fibrosis | Electrophoresis, Gel, Pulsed-Field | Female | Haemophilus Infections | Haemophilus influenzae | Humans | Infant | Male | Microbial Sensitivity Tests | Respiratory System | Mutation
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