[Approach to the diagnosis of pertussis infection: evaluation of cases suffering from prolonged cough symptoms].

This study was performed on cases admitted to Sami Ulus Pediatric Health and Diseases Training and Research Hospital because of cough lasting two weeks or more between November, 2001 and April, 2003. According to pertussis case definitions, patient's information of each 66 probable cases complied with clinical criteria from 0-15 age group were recorded on questionnaire and nasopharyngeal samples were taken. Specimens were sent to Refik Saydam National Hygiene Centre, Pertussis Reference Laboratory in order to perform specific culture, direct fluorescent antibody (DFA) and polymerase chain reaction (PCR). Bordetella pertussis was isolated on cultures of two cases (3%) and the same specimens were found positive by DFA. Direct PCR results of nasopharyngeal samples were not evaluated since false positive reactions were obtained with one or more negative controls in different series. Since a symptomatic contact of any culture proven case is also defined as confirmed case by the standard case definitions, three of 66 cases (4.5%) together with a symptomatic contact of one of the culture positives were classified as confirmed pertussis in this study.