Evaluation of the Uro4 HB&L™ system for the rapid diagnosis of lower respiratory tract infections in intensive care units

Respiratory tract infection is a common and important problem in the intensive care unit (ICU) setting. It has been demonstrated that an appropriate initial regimen or its early modification (within 6-12h from diagnosis) based on microbiological results leads to a higher survival rate. Here we evaluated the Uro4 HB&L automated system for the rapid diagnosis of respiratory tract infections in ICU patients. A total of 644 lower respiratory tract specimens collected from 400 inpatients from nine ICUs at the Padova University hospital were collected during a 12-month period. All samples were processed both with the Uro4 HB&L system and with the reference culture method. Out of 322 samples, 312 were concordant positive, 276 out of 276 were concordant negative, 66 samples were declared uncertain and discarded because of an excess in turbidity. The diagnostic accuracy was good, compared with standard cultures from BAL specimens, in terms of sensitivity (0.972), specificity (1.00), likelihood ratios and diagnostic odds ratio. Ten discordant samples, resulted positive with the reference culture and not detectable with the Uro4 HB&L, were confirmed positive by Gram-stain smear analysis performed after incubation. The Uro4 HB&L system, compared to the standard culture method, revealed a very high sensitivity and a full specificity in identifying clinically relevant microorganisms from lower respiratory tract samples after merely 6h. Overall our results indicate that Uro4 HB&L is a reliable system for the surveillance of the respiratory tract infections in ICUs; it could speed up the laboratory procedures and provide fast, reliable results for clinicians.