[Rapid method for identifying Escherichia coli and species of the Proteeae tribe in urine]. / Método rápido para identificar Escherichia coli y especies de la tribu Proteeae en orina.

ABSTRACT

BACKGROUND: To evaluate the possibility of using the determination of beta-glucuronidase and phenylalanine deaminase activity directly from urine samples for rapid detection (2 hours) of the presence of Escherichia coli and species of the Proteeae tribe. METHODS: To detect beta-glucuronidase activity methyl-umbelipheryl-beta-D-glucuronic was used as a substrate. The presence of fluorescence after incubation at 37 degrees C for 2 hours indicated a positive reaction. While phenylalanine was used as a substrate for detecting phenylalanine deaminase activity, FeCl3 was added after incubation at 37 degrees C for 2 hours with a greenish color being observed indicating phenylalanine deaminase activity. RESULTS: The detection of Escherichia coli by beta-glucuronidase activity presented sensitivity and specificity of 0.91 and 0.99, respectively. The positive predictive value was 0.96 and the negative predictive value was 0.98, whereas the determination of the phenylalanine deaminase activity with the aim of detecting species of the Proteeae tribe presented the following results; sensitivity 0.92, specificity 0.99, positive predictive value 0.94 and negative predictive value 0.99. CONCLUSIONS: The determination of beta-glucuronidase and phenylalanine deaminase activities directly from urine sediment has been demonstrated as a rapid and specific test for detecting the presence of Escherichia coli and species of the Proteeae tribe, therefore it must be considered as a useful test in early diagnosis of urinary infection thereby facilitating the administration of appropriate antibiotic treatment.