87 Detection of enterotoxins (A–E) from Staphylococcus aureus isolated from CF sputum: Clinical significance of enterotoxigenic (ET+) strains of S. aureus in paediatric and adult CF patients

Abstract

Objectives Staphylococcus aureus (SA) can produce several entertoxins (ETs) that may cause nausea and vomiting when ingested. Chronic colonisation of the CF airways by high numbers (10 8 –10 9 cfu/ml sputum) of ET+ SA may allow ET production in situ in the CF airways. It was therefore the aim of this study to examine CF SA isolates and CF sputum for the presence of ETs. Methods Sixteen CF patients, who were chronic/intermittently colonised with SA, were selected at random from adult and paediatric CF services. Following laboratory optimisation of an ELISA (R-Biopharm Rhone) for the detection of SA ETs A–E, spent Brain Heart Infusion broth from late logarithmic SA cultures were examined for SA ETs. In addition, sputum sol samples from 19 SA positive patients were also tested for ETs. Results Five of 16 cultures (31.3%) were positive for ETs. These samples came from 4 females and 1 male, including 4 children and 1 adult [4 delF508 homogygous + 1 delF508/R117H]. When controlled for delF508/delF508, these ET+ SA patients were compared to CF patients with chronic/intermittent colonisation with known ET − SA strains. There was no significant difference (p>0.05) in %FEV1 and BMI values between these two patient groups. ETs were not detected in any of the sputum sol samples. Conclusion The carriage of ETs in CF-related SA (31.3%) is approximately half that previously reported from SA isolated from non-CF student nasal swabs (66.7%). Further work is required to optimise detection of ETs in sputum sol samples.