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Antibacterial resistance among Streptococcus pneumoniae from 4 centres in Thailand: results from the Survey of Antibiotic Resistance (SOAR), 20072009

Abstract number: P1678

Khantawa B., Baosount V., Warachit B., Yodsawat C., Malatham K., Santanirand P., Reechaipichitkul W., Lulitanond A., Chaimance P., Sawatwipachai S., O'Brien D.

Objectives:Streptococcus pneumoniae is the main bacterial pathogens implicated in community-acquired respiratory tract infections (CARTIs), which occur frequently and account for significant morbidity and mortality. The emergence of drug resistance in these organisms has complicated empirical treatment of such infections. It is therefore imperative to know the susceptibility pattern of CARTI pathogens when selecting an antimicrobial agent for empirical therapy.

Methods: The study was split into three phases. Phase 1: disk diffusion to determine susceptibilities to key therapeutic drugs (oxacillin, erythromycin, clindamycin, co-trimoxazole. tetracycline, chloramphenicol, ofloxacin) Phase 2: Strains that were non-susceptible to oxacillin and/or erythromycin were tested against other antibiotics (penicillin, amoxicillin/clavulanate, cefprozil, ceftriaxone, azithromycin, clarithromycin, levofloxacin) by using Etest. Phase 3: Erythromycin-clindamycin double-disk test was used to determine the resistance phenotypes of erythromycin-resistant S. pneumoniae isolates. Prior to the start of each phase of the survey, a quality control four-day run-in period test was performed. Susceptibility was assessed using CLSI interpretive criteria.

Results: In total 281 (Phase 1), 159 (Phase 2) and 97 (Phase 3) S. pneumoniae strains were tested from four centres in Thailand. 49.8% (140/281) of SP were penicillin-susceptible and 50.2% (141/281) were penicillin-nonsusceptible based on oxacillin resistance (Phase 1) and CLSI 2009 oral penicillin breakpoints (Phase 2). Overall, resistance to erythromycin was 34.6% (97/281). Among erythromycin and/or penicillin resistant strains, the level of susceptibility to amoxicillin/clavulanate and azithromycin/clarithromycin was 98.7% (157/159) and 25.8% (41/159) respectively. Among 97 erythromycin resistant strains, 57.7% (56/97) were MLSB types and 42.3% (41/97) were M types.

Conclusion: Amoxicillin/clavulanate retained excellent in vitro activity against S. pneumoniae strains. Among S. pneumonaie isolates, the prevalence of macrolide resistance was high.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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