Dados do Trabalho

Título

Laboratory diagnosis of Bordetella pertussis in Brazil: overview of culture and real-time PCR from 2010 to 2023

Introdução

The diagnoses of pertussis can be challenging due to the broad spectrum of signs/symptoms, besides other respiratory pathogens cause pertussis-like illness. In Brazil, suspected cases of pertussis are confirmed by clinical, epidemiological or laboratory criteria. Confirmation of laboratory criteria is based on the isolation of B. pertussis through nasopharyngeal secretion culture and/or by detection of bacterial DNA by real-time (quantitative) polymerase chain reaction (qPCR).

Objetivo (s)

The objective of this study was to describe the results of the culture and qPCR, in samples analyzed in the Adolfo Lutz Institute - National Reference Laboratory for Pertussis in Brazil.

Material e Métodos

From January 2010 to December 2023, were analyzed a total of 37,453 samples of nasopharyngeal secretions collected from patients and/or contacts suspected pertussis. The samples were cultured on charcoal agar with 10% sterile defibrinated horse blood and cephalexin and incubated at 35-37°C for ten days. qPCR was performed in the thermocycler Applied Biosystems™ 7500 Fast Real-Time PCR Systems, using specific primers and probes for the detection of the toxin gene ptxS1 and the insertion element IS481

Resultados e Conclusão

11% of the samples (4,082) were positive on qPCR and/or culture tests for detection of B. pertussis. 1,327 (3.5%) samples were positive using both growth culture and qPCR; 3.841 (10.0%) were only qPCR positive and 241 (0.6%), only culture positive. The higher number of positive was in 2011 to 2014, that was considered epidemic period in Brazil, with 541 and 1,074 samples positives by qPCR, respectively. qPCR is an excellent complementary tool to culture for the laboratory diagnosis of pertussis. However, failure to recognize the disease, especially among adolescents/adults, contributes to underreporting. Our data may represent only a fraction of the current number of pertussis cases occurring in this country.

Palavras Chave

Bordetella pertussis; qPCR; culture; laboratory diagnosis