Increase in pertussis cases along with high prevalence of two emerging genotypes of Bordetella pertussis in Perú, 2012

BMC Infectious Diseases

Research Article

D. Hozbor¹  C. Padilla²  H. Bailon²  N. León-Janampa² 

[1] Departamento de Ciencias Biológicas, Laboratorio VacSal del Instituto de Biotecnología y Biología Molecular, Facultad de Ciencias Exactas Universidad Nacional de La Plata, CONICET, La Plata, Argentina;Laboratorio de Biotecnología y Biología Molecular, Centro Nacional de Salud Pública, Instituto Nacional de Salud, Ministerio de Salud, Lima, Peru;

关键词: Pertussis;    Bordetella pertussis;    Genotype;    Pulsed-field gel electrophoresis;    Perú;   

DOI  :  10.1186/s12879-016-1700-2

 received in 2015-09-03, accepted in 2016-07-08,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundAs has occurred in many regions worldwide, in 2012 the incidence of pertussis increased in Perú. This epidemiologic situation has been associated with a waning vaccine-induced immunity and the adaptation of Bordetella pertussis to vaccine-induced immunity along with improved diagnostic methods.MethodsThe study comprised a total of 840 pertussis-suspected cases reported in Perú during 2012. We summarize here the distribution of pertussis cases according to age and immunization status along with the immunization-coverage rate. Laboratory diagnosis was performed by culture test and real-time polymerase-chain reaction (PCR). B. pertussis bacteria recovered from infected patients were characterized by pulsed-field gel electrophoresis (PFGE), and the DNA sequencing of the pertussis-toxin (promoter and subunit A), pertactin, and fimbriae (fim2 and fim3) genes.ResultsFrom the total pertussis-suspected cases, 191 (22.7 %) infections were confirmed by real-time PCR and 18 through cultivation of B. pertussis (2.1 %), while one infection of B. parapertussis (0.11 %) was also detected by culture. Pertussis was significantly higher in patients that had had 0–3 vaccine doses (pentavalent vaccine alone) than in those who had had 4–5 vaccine doses (pentavalent plus DwPT boosters) at 94.3 vs. 5.7 %, respectively (p < 0.00001). The relative risk (RR) for patients with 4–5 doses compared to those with fewer than 4 doses or no dose was 0.23 (95 % Confidence Interval: 0.11–0.44), while the vaccine effectiveness was 77 % and coverage 50.5 %. Genetic analysis of B. pertussis isolates from different Peruvian regions detected two clonal groups as identified by PFGE. Those two groups corresponded to the B. pertussis genotypes emerging worldwide ptxP3-ptxA1-prn2 or 9-fim3-1 and ptxP3-ptxA1-prn2 or 9-fim3-2.ConclusionsTwo emerging B. pertussis genotypes similar to isolates involved in worldwide epidemics were detected in Perú. Low vaccine coverage (<50 %) and genetic divergence between the vaccine-producing strain and the local isolates could contribute to this pertussal epidemic.

【 授权许可】

CC BY   
© The Author(s). 2016