Takumi Moriuchi1, Ork Vichit2, Yong Vutthikol2, Md Shafiqul Hossain3, Chham Samnang3, Kohei Toda4, Varja Grabovac5, Yukihiro Hiramatsu6, Nao Otsuka6, Keigo Shibayama6, Kazunari Kamachi7. 1. Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo, Japan; Department of Pediatrics, St Marianna University School of Medicine, Kawasaki, Japan. 2. National Immunization Program, Ministry of Health, Cambodia. 3. World Health Organization, Country Office, Cambodia. 4. World Health Organization, Country Office, Philippines. 5. World Health Organization, Western Pacific Regional Office, Manila, Philippines. 6. Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo, Japan. 7. Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo, Japan. Electronic address: kamachi@nih.go.jp.
Abstract
OBJECTIVES: This study sought to determine the genotypes of circulating Bordetella pertussis, the causative agent of pertussis, in Cambodia by direct molecular typing of clinical specimens. METHODS: DNA extracts from nasopharyngeal swabs obtained from 82 pertussis patients in 2008-2016 were analyzed by multilocus variable-number tandem repeat analysis (MLVA). B. pertussis virulence-associated allelic genes (ptxA, prn, and fim3) and the pertussis toxin promoter ptxP were also investigated by DNA sequence-based typing. RESULTS: Forty-four DNA extracts (54%) yielded a complete MLVA profile, and these were sorted into 8 MLVA types (MT18, MT26, MT27, MT29, MT43, MT72, MT95, and MT200). MT27 and MT29, which are common in developed countries, were the predominant strain types (total 73%). The predominant profile of virulence-associated allelic genes was the combination of ptxP3/ptxA1/prn2/fim3A (48%). MT27 strains were detected during the entire study period, whereas MT29 strains were only found in 2014-2016. CONCLUSIONS: The B. pertussis population in Cambodia, where a whole-cell pertussis vaccine (WCV) has been continuously used, resembled those observed previously in developed countries where acellular pertussis vaccines are used. Circulating B. pertussis strains in Cambodia were distinct from those in other countries using WCVs.
OBJECTIVES: This study sought to determine the genotypes of circulating Bordetella pertussis, the causative agent of pertussis, in Cambodia by direct molecular typing of clinical specimens. METHODS: DNA extracts from nasopharyngeal swabs obtained from 82 pertussis patients in 2008-2016 were analyzed by multilocus variable-number tandem repeat analysis (MLVA). B. pertussis virulence-associated allelic genes (ptxA, prn, and fim3) and the pertussis toxin promoter ptxP were also investigated by DNA sequence-based typing. RESULTS: Forty-four DNA extracts (54%) yielded a complete MLVA profile, and these were sorted into 8 MLVA types (MT18, MT26, MT27, MT29, MT43, MT72, MT95, and MT200). MT27 and MT29, which are common in developed countries, were the predominant strain types (total 73%). The predominant profile of virulence-associated allelic genes was the combination of ptxP3/ptxA1/prn2/fim3A (48%). MT27 strains were detected during the entire study period, whereas MT29 strains were only found in 2014-2016. CONCLUSIONS: The B. pertussis population in Cambodia, where a whole-cell pertussis vaccine (WCV) has been continuously used, resembled those observed previously in developed countries where acellular pertussis vaccines are used. Circulating B. pertussis strains in Cambodia were distinct from those in other countries using WCVs.
Authors: Kazunari Kamachi; Hong T Duong; Anh D Dang; T Hai; Do Do; Kentaro Koide; Nao Otsuka; Keigo Shibayama; Ha Thi Thu Hoang Journal: Emerg Infect Dis Date: 2020-10 Impact factor: 6.883
Authors: Adriana Cabal; Daniela Schmid; Markus Hell; Ali Chakeri; Elisabeth Mustafa-Korninger; Alexandra Wojna; Anna Stöger; Johannes Möst; Eva Leitner; Patrick Hyden; Thomas Rattei; Adele Habington; Ursula Wiedermann; Franz Allerberger; Werner Ruppitsch Journal: Emerg Infect Dis Date: 2021-03 Impact factor: 6.883