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摘要
Objectives: Macrolides, such as azithromycin and erythromycin, are first-line drugs for the (prophylactic) treatment of pertussis. This study aimed to screen for macrolide-, quinolone- or trimethoprim/sulfamethoxazole (SXT)-resistant strains among Finnish Bordetella pertussis isolates. Methods: Antimicrobial susceptibility testing was performed on 148 B. pertussis strains isolated during 2006-2017. Isolates were analysed by allele-specific PCR for detection of the macrolide resistance-associated mutation A2047G in the 23S rRNA gene. The gyrA gene was sequenced for detection of the A260G mutation associated with quinolone resistance. For phenotyping, a random selection was made by selecting every third isolate (n=50) to determine the minimum inhibitory concentrations (MICs) for erythromycin and azithromycin by Etest and the inhibition zone size for nalidixic acid (NAL) and SXT by single disk diffusion assay. Results: Neither the macrolide resistance-associated mutation A2047G nor the quinolone resistance-associated mutation A260G was detected in any of the B. pertussis isolates. MICs of azithromycin and erythromycin ranged between 0.016-0.19 mu g/mL and 0.016-0.25 mu g/mL, respectively. The size of the inhibition zone surrounding the NAL disk ranged between 22-27 mm in diameter. The inhibition zone surrounding the SXT disk ranged between 24-37 mm in diameter. No isolates resistant to any of the tested antimicrobials were identified. Conclusions: The allele-specific PCR is a simple and useful tool for screening B. pertussis resistance to macrolides. All Finnish isolates tested were susceptible to macrolides, quinolones and SXT.
- 出版日期2018-9
- 单位首都医科大学
