Kageto Yamada1, Ryoichi Saito2, Saori Muto3, Masakazu Sasaki4, Hinako Murakami4, Kotaro Aoki5, Yoshikazu Ishii5, Kazuhiro Tateda5. 1. Department of Clinical Laboratory, Toho University Medical center Omori Hospital, Tokyo, Japan. Electronic address: kageto.yamada@med.toho-u.ac.jp. 2. Department of Microbiology and Immunology, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo, Japan. 3. Department of Clinical Laboratory, Tokyo Metropolitan Health and Medical Treatment Corporation Toshima Hospital, Tokyo, Japan. 4. Department of Clinical Laboratory, Toho University Medical center Omori Hospital, Tokyo, Japan. 5. Department of Microbiology and Infectious Disease, Toho University School of Medicine, Tokyo, Japan.
Abstract
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.
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.