Comparison between nasopharyngeal swab and nasal wash, using cluture and PCR, in the detection of potential repiratory pathogens

Background: Nasopharyngeal carriage of potential pathogens is important as it is both the major source of

transmission and the prerequisite of invasive disease. New methods for detecting carriage could improve comfort,

accuracy and laboratory utility. The aims of this study were to compare the sensitivities of a nasopharyngeal swab

(NPS) and a nasal wash (NW) in detecting potential respiratory pathogens in healthy adults using icrobiological

culture and PCR.

Results: Healthy volunteers attended for nasal washing and brushing of the posterior nasopharynx. Conventional

and real-time PCR were used to detect pneumococcus and meningococcus. Statistical differences between the

two nasal sampling methods were determined using a nonparametric Mann-Whitney U test; differences between

culture and PCR methods were determined using the McNemar test. Nasal washing was more comfortable for volunteers than swabbing (n = 24). In detection by culture, the NW was

significantly more likely to detect pathogens than the NPS (p < 0.00001). Overall, there was a low carriage rate of

pathogens in this sample; no significant difference was seen in the detection of bacteria between culture and PCR

methods.

Conclusions: Nasal washing and PCR may provide effective alternatives to nasopharyngeal swabbing and classical

microbiology, respectively.