Identification of Bordetella pertussis in nasopharyngeal swabs using the polymerase chain reaction: evaluation of detection methods.

A 183 base pairs or 153 base pairs DNA fragment from a repetitive region of the Bordetella pertussis genome was amplified in a polymerase chain reaction. The sensitivities of three different detection methods (Enzymun Test, silver stained polyacrylamide gel, ethidium bromide stained agarose gel) after amplification by polymerase chain reaction showed that both a one-time polymerase chain reaction (35 cycles) with Enzymun testing as well as a nested polymerase chain reaction with either of the electrophoresis methods have high levels of sensitivity for detection of the infectious organism in nasopharyngeal swabs. Smears from 53 children with whooping cough and from 50 children without infections were analysed, using these methods. 51 patients with whooping cough gave positive test results, while 2 of the sick patients and all the control children gave negative results.