Enterococcus faecium and Enterococcus faecalis in blood of newborns with suspected nosocomial infection

Abstract

Enterococci are Gram-positive cocci saprophyte of the human gastrointestinal tract, diners who act as opportunistic pathogens. They can cause infections in patients hospitalized for a long time or who have received multiple antibiotic therapy. Enterococcus faecalis and Enterococcus faecium are the most common species in human infections. To evaluate the possibility of rapid detection of these species and their occurrence in the blood of newborns with suspected nosocomial infection, blood samples were collected from 50 newborns with late infections, admitted to the Neonatal Care Unit of the University Hospital Federal de Mato Grosso do Sul (UFMS-HU), from September 2010 to January 2011. The samples were subjected to conventional PCR and real time PCR (qPCR) to search for Enterococcus faecium and Enterococcus faecalis, respectively. The PCR results were compared with respective blood cultures from 40 patients. No blood cultures were positive for Enterococci, however, eight blood samples were identified as genomic DNA of Enterococcus faecium by qPCR and 22 blood samples were detected as genomic DNA of Enterococcus faecalis by conventional PCR. These findings are important because of the clinical severity of the evaluated patients who were found positive by conventional PCR and not through routine microbiological methods.

Fig. 1. Samples positive for Enterococcus faecium by Real-Time PCR.

Fig. 2. Conventional PCR for Enterococcus faecalis present in blood of newborns with suspected nosocomial infection. (M) 50 bp ladder marker (1µg); (C+) positive control for E. faecalis, ATCC 19433. (C–) negative control; 22 positive samples = (11,13,14,16,17,18,20,21,25,28,29,30,31,32,35,38,40,42,43,44,46,50).