RESUMO
OBJECTIVES: Campylobacter jejuni (C. jejuni) is one of the most common pathogens that causes gastroenteritis. Because there is currently insufficient epidemiological information about the antimicrobial susceptibility and molecular characterisation of clinical isolates of C. jejuni in Japan, this study carried out antimicrobial susceptibility testing and multilocus sequence typing (MLST) of clinical C. jejuni isolates in Tokyo between 2000-2017. METHODS: Antimicrobial susceptibility to erythromycin and ciprofloxacin was tested using the broth microdilution method in 430 C. jejuni clinical isolates collected over 18 years, between 2000-2017, at a Tokyo general hospital. To observe the sequence type (ST) evolution, 82 isolates were chosen from three non-consecutive years (16 isolates from 2000, 25 isolates from 2008, and 41 isolates from 2017) and analysed by MLST as a molecular characterisation test. Mutations in the quinolone resistance-determining region of the gyrA and gyrB genes were identified. RESULTS: The rate of resistance to erythromycin was low, but that of ciprofloxacin resistance was 34.9% in 2000-2008 and 41.9% in 2009-2017. The most common clonal complex (CC) identified during the entire period was CC21; ST4526 with ciprofloxacin resistance was highly prevalent in 2017 (6 of 11; 54.5%). CONCLUSION: The results indicate that the rate of resistance to quinolone has gradually increased. Since ST4526 was not isolated in 2000 and 2008, it is likely that ST4526 is rapidly increasing in Japan.
Assuntos
Infecções por Campylobacter/microbiologia , Campylobacter jejuni/classificação , DNA Girase/genética , Tipagem de Sequências Multilocus/métodos , Análise de Sequência de DNA/métodos , Proteínas de Bactérias/genética , Campylobacter jejuni/efeitos dos fármacos , Campylobacter jejuni/genética , Campylobacter jejuni/isolamento & purificação , Ciprofloxacina/farmacologia , Farmacorresistência Bacteriana , Eritromicina/farmacologia , Hospitais Gerais , Humanos , Japão , Testes de Sensibilidade Microbiana , MutaçãoRESUMO
Moraxella catarrhalis causes respiratory infections. In this study, fluoroquinolone-resistant strains were selected in vitro to evaluate the mechanism of fluoroquinolone resistance. Strains with reduced fluoroquinolone susceptibility were obtained by stepwise selection in levofloxacin, and fluoroquinolone targets gyr and par were sequenced. Six novel mutations in GyrA (D84Y, T594dup, and A722dup), GyrB (E479K and D439N), and ParE (Q395R) involved in M. catarrhalis resistance to fluoroquinolones were revealed.
