Genotyping and macrolide-resistant mutation of Bordetella pertussis in East and South-East Asia.

OBJECTIVES: Macrolide-resistant Bordetella pertussis (MRBP) has been emerging and prevailing in mainland China since 2011. In this study, we aimed to investigate the genotype and macrolide resistance of circulating B. pertussis in East and Southeast Asia using genetic analyses. METHODS: A total of 302 DNA extracts from clinical specimens and isolates from 2010 to 2020 were analyzed: 145 from Vietnam, 76 from Cambodia, 48 from Taiwan, and 33 from Japan. Genotypes were determined by multilocus variable-number tandem-repeat analysis (MLVA). Macrolide-resistant A2047G mutation in B. pertussis 23S rRNA was investigated using the duplex Cycleave real-time polymerase chain reaction (PCR) assay. Whole-genome sequencing was performed on two MRBP isolates that were identified for the first time in Taiwan. RESULTS: Overall, 286 DNA extracts (95%) generated a complete MLVA genotype and 283 DNA extracts (94%) yielded a complete result for the A2047G mutation analysis. The A2047G mutation was detected in 18 DNA extracts: fourteen from Vietnam, one from Cambodia, two from Taiwan, and one from Japan. Most of them (78%) showed the genotypes MT104 and MT195, which have previously been reported in Chinese MRBP isolates. Further, the Taiwanese MRBP isolates were classified into the MT104 clade of Chinese MRBP isolates. CONCLUSION: After MRBP emerged and spread in mainland China, it may have spread to East and Southeast Asia in the 2010s. Continued surveillance targeting the A2047G mutation of MRBP is needed to prevent further spread of this emerging pathogen.

Community-based household assessment of human papillomavirus (HPV) vaccination coverage and acceptability - HPV vaccine demonstration program, Cambodia - 2017.

BACKGROUND: In 2017, the Cambodia Ministry of Health introduced human papillomavirus (HPV) vaccine through primarily school-based vaccination targeting 9-year-old girls. Vaccination with a two-dose series of HPV vaccine took place in six districts in two provinces as a demonstration program, to better understand HPV vaccine delivery in Cambodia. METHODS: We conducted a community-based coverage survey using a one-stage sampling design to evaluate dose-specific vaccination coverage among eligible girls (those born in 2007 and residents in the areas targeted by the campaign). The household-level survey also assessed factors associated with vaccine acceptability and communication strategies. Trained data collectors interviewed caregivers and girls using a standard questionnaire; vaccination cards and health facility records were reviewed. RESULTS: Of the 7594 households visited in the two provinces, 315 girls were enrolled in the survey (188 in Siem Reap; 127 in Svay Rieng). Documented two-dose HPV vaccination coverage was 84% (95% confidence interval [CI]: 78-88%) overall [85% (95% CI: 78-90%) in Siem Reap; 82% (95% CI: 73-88%) in Svay Rieng.] Almost all girls (>99%) were reported to be enrolled in school and over 90% of respondents reported receipt of vaccine in school. Knowledge of HPV infection and associated diseases was poor among caregivers and girls; however, 58% of caregivers reported "protection from cervical cancer" as the primary reason for the girl receiving vaccine. No serious adverse events after immunization were reported. CONCLUSIONS: The HPV vaccine demonstration program in Cambodia achieved high two-dose coverage among eligible girls in both provinces targeted for vaccination in 2017, through primarily school-based vaccination. High school enrollment and strong microplanning and coordination were seen throughout the campaign. Cambodia will use lessons learned from this demonstration program to prepare for national introduction of HPV vaccine.

Molecular epidemiology of Bordetella pertussis in Cambodia determined by direct genotyping of clinical specimens.

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.