The Turkish Journal of Pediatrics
2009 , Vol 51 , Num 4
Comparison of Nasopharyngeal Culture, Polymerase Chain
Reaction (PCR) and Serological Test for Diagnosis of
Pertussis
1Infectious Disease Unit, Department of Pediatrics, and 2Pediatric Microbiology Laboratory, Hacettepe University Faculty
of Medicine, Ankara, Turkey
This prospective study, which was designed to compare nasopharyngeal culture,
polymerase chain reaction (PCR) and serology in the diagnosis of pertussis,
covered 35 children aged between 0 and 16 who were admitted to Hacettepe
University İhsan Doğramacı Children’s Hospital between 1 March 2005 and
31 August 2006 with coughing for 7 days or longer, paroxysmal cough of
any duration, or cough with inspiratory whoop and/or vomiting (or apnea)
after coughs. The demographic data and vaccination history of the patients
were recorded. During the initial examination, samples were taken from the
posterior nasopharynx for Bordetella pertussis (B. pertussis) culture and PCR
analysis. In order to determine antibody positivity and antibody levels against
B. pertussis antigens, serum samples were taken during the initial examination
(acute phase) and two weeks later (convalescent phase). In the first serum
sample, immunoglobulin M (IgM) was determined against pertussis toxin. In
the first and second samples, IgA and IgG antibodies were evaluated against
pertussis toxin and filamentous hemagglutinin. Culture yielded negative
results in all of the patients. PCR was positive in two cases (5.7%). In the
PCR-positive patients, IgM, IgA and IgG type anti-pertussis antibodies were
found to be positive in the first serum samples, and IgA and IgG antibodies
were found to be positive in the second serum samples. Therefore, it was
considered that serology could be as sensitive as PCR when type IgM, IgA and
IgG antibodies were found to be positive against a minimum of two antigens
of B. pertussis. In conclusion, both PCR and serologic tests -if evaluating all
types of antibodies to a minimum of two antigens of B. pertussis obtained
in both acute and convalescent sera- could be more sensitive than culture
in the diagnosis of pertussis.
Keywords :
pertussis, culture, polymerase chain reaction (PCR), serology.