LAVADO P, CANICA M; Interscience Conference on Antimicrobial Agents and Chemotherapy.
Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 1999 Sep 26-29; 39: 142 (abstract no. 59).
NIH Dr. Ricardo Jorge, Lisbon, PORTUGAL.
BACKGROUND: The resistance of Haemophilus influenzae (Hi) to beta-lactams has developed significantly during the last 25 years, mainly as a consequence of beta-lactamase production. Since they were first described, in the 80's, beta-lactamase negative ampicillin-resistant (BLNAR) strains are now emerging in many countries. OBJECTIVES: To assess the evolution of ampicillin resistance in Portugal and look for a possible clonal diffusion of BLNAR strains.METHODS: 639 Hi strains (85% of respiratory origin) were collected during 1997-98, from 12 hospitals in different regions of Portugal. beta-lactamase production was detected with nitrocefin. Minimum inhibitory concentrations (MIC) to ampicillin and amoxicillin-clavulanate were determined by the agar dilution method (NCCLS, 1999). Capsular typing was performed by the slide agglutination method. Molecular typing by pulsed-field gel electrophoresis (PFGE) was performed for the BLNAR strains, using SmaI.RESULTS: Overall 63 strains (10%) produced beta-lactamase (bl+) (1 mg/ L /= 1 mg/L and amoxicillin-clavulanate MIC >/= 2 mg/L were considered BLNAR. All BLNAR strains were nontypeable. PFGE of 22 BLNAR strains showed 19 different patterns. 3 strains isolated from 2 babies with conjunctivitis, from different geographic areas in different years, had the same profile. 2 of the 3 strains were from the same baby, but different sources.CONCLUSIONS: Comparing these results to previous ones (2000 strains in 1989-92), we maintain in Portugal 10% of beta-lactamase production, although we assist to an increase of BLNAR strains: 0.7% from 600 strains in 1989-92 to 4.5% in this study. Molecular typing of BLNAR strains showed only 3 genetically related strains; thus the evolution of BLNAR in Portugal is not due to the dissemination of a single clone. These findings suggests the need of a continuous surveillance of Hi BLNAR in Portugal.
Publication Types:
Keywords:
- Amoxicillin
- Amoxicillin-Potassium Clavulanate Combination
- Ampicillin
- Ampicillin Resistance
- Cephalosporins
- Electrophoresis, Gel, Pulsed-Field
- Epidemiology, Molecular
- Haemophilus Infections
- Haemophilus influenzae
- Humans
- Infant
- Microbial Sensitivity Tests
- Portugal
- beta-Lactamases
- genetics
- nitrocefin
Other ID:
UI: 102244996
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