title: Serodiagnosis as adjunct assay for pertussis infection in São Paulo, Brazil.
abstract: Pertussis remains an important public health problem in many countries despite extensive immunization. Cultures and real-time PCR (RT-PCR) assays are the recommended pertussis diagnostic tests, but they lack sensitivity at the later stage of the disease. This study introduces the IgG anti-pertussis toxin enzyme-linked immunosorbent assay (PT ELISA) in our routine diagnosis to improve disease burden estimation. Serum samples and nasopharyngeal swabs (n = 503) were collected at the same time from patients presenting with cough illness suspected of being pertussis and tested by the PT ELISA and culture and/or RT-PCR, respectively. Patients were separated into three age groups: group 1, <1 year (n = 260; mean age, 3 months), group 2, 1 to 6 years (n = 81; mean age, 3 years), and group 3, ≥7 years (n = 162; mean age, 26 years). The times (means) from cough onset to specimen collection were 16, 24, and 26 days, respectively. In group 1, 83 (82.2%) of 101 positive cases were positive for pertussis by culture/RT-PCR, while 40 (39.6%) tested positive by PT ELISA. In group 2, 6 (19.4%) of 31 positive cases were culture/RT-PCR positive, and 29 (93.6%) were seropositive. In group 3, 13 (13.8%) of 94 positive cases were positive by culture/RT-PCR and 91 (96.8%) were positive by serology. Culture/RT-PCR detected more cases of pertussis in infants (P < 0.0001), whereas the PT ELISA detected more cases in adolescents and adults (P < 0.0001). The timing between cough onset and specimen collection or recent vaccination may have partially affected our results. Serology is a suitable, cost-effective, and complementary pertussis diagnostic tool, especially among older children, adolescents, and adults during the later disease phase.
authors.affiliation: Immunology Center, Bacteriology Center, Instituto Adolfo Lutz, São Paulo, Brazil.
authors.forename: Lourdes R A
authors.initials: LR
authors.lastname: Vaz-de-Lima
authors.forename: Monte D
authors.initials: MD
authors.lastname: Martin
authors.forename: Lucia C
authors.initials: LC
authors.lastname: Pawloski
authors.forename: Daniela
authors.initials: D
authors.lastname: Leite
authors.forename: Karen C P
authors.initials: KC
authors.lastname: Rocha
authors.forename: Cyro A
authors.initials: CA
authors.lastname: de Brito
authors.forename: Tânia M I
authors.initials: TM
authors.lastname: Vaz
authors.forename: Luciano Moura
authors.initials: LM
authors.lastname: Martins
authors.forename: Danielly P
authors.initials: DP
authors.lastname: Alvarenga
authors.forename: Ana F
authors.initials: AF
authors.lastname: Ribeiro
authors.forename: Telma R M P
authors.initials: TR
authors.lastname: Carvalhanas
authors.forename: Rosa M D
authors.initials: RM
authors.lastname: Nakasaki
authors.forename: Silvia S
authors.initials: SS
authors.lastname: Oliveira
authors.forename: Eliseu A
authors.initials: EA
authors.lastname: Waldman
authors.forename: Maria Lucia
authors.initials: ML
authors.lastname: Tondella
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood*; D001431:Bacteriological Techniques / Q000379:methods; D001886:Bordetella pertussis / Q000235:genetics / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification; D001938:Brazil; D002648:Child; D002675:Child, Preschool; D003955:Diagnostic Tests, Routine / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods; D009305:Nasopharynx / Q000382:microbiology; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods; D014917:Whooping Cough / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G