Improved early diagnosis of Pseudomonas aeruginosa by real-time PCR to prevent chronic colonisation in a paediatric cystic fibrosis population

Early detection of Pseudomonas aeruginosa in children with cystic fibrosis is hampered by the need to process a sub-optimal specimen type, namely cough swabs, which are known to have a lower positive yield than sputa or more invasive samples. This delay in the detection of low levels of P. aeruginosa could potentially result in the loss of an opportunity to initiate early aggressive antibiotic therapy and result in chronic colonisation, with a poorer overall prognosis. Quantitative real-time PCR (qPCR) offers an opportunity to increase the detection rate of P. aeruginosa compared to traditional culture techniques. This study examined 500 cough swabs and 42 sputum samples from paediatric patients and showed that detection of P. aeruginosa could be increased in both sample types by 100% and 45% respectively. Overall the sensitivity was 100% and specificity of 58% when compared to culture as a gold standard. These results although initially promising require careful consideration both from a treatment and infection control standpoint as the significance of detection of very low levels of P. aeruginosa is unclear.