Characterization of vancomycin-resistant Enterococcus faecium in children admitted to a pediatric oncology hospital in the city of São Paulo Brazil
Thomás Cardoso Chagas Neto, Luciana Ferreira Franco, Fabianne CarlesseAbstract
Background
Vancomycin-resistant Enterococcus (VRE) is an important microorganism in nosocomial infections in pediatric oncology patients. Immunosuppression, prolonged use of antimicrobials (particularly cephalosporins and vancomycin) and invasive procedures are the main risk factors for acquiring infection by this agent. Furthermore, studies have shown that exposure of a patient bed previously occupied by a VRE carrier can be considered a risk factor for acquiring new in-patient infections. The aim of this study was to evaluate the colonization of Enterococcus faecium vancomycin- resistant (EfmVRE) and further infection in children admitted to a reference pediatric oncology hospital.
Methods
Retrospective cohort study conducted at a reference pediatric oncology hospital in Sao Paulo, Brazil and the Federal University of Sao Paulo. Inclusion criteria: samples from patients who were followed up during the period from January to December 2009 and who presented a positive surveillance culture for EfmVRE with a later positive clinical culture for the same agent were included in the study. We analyzed 10 samples of EfmVRE in 2009, two samples from each patient: one representative of colonization site and another of the site of infection using the analysis of the profile generated after chromosomal restriction digestion (SmaI) of the samples by PFGE, then analyzed byBioNumerics ® software, according to the microrestriction pattern obtained.
Results
We observed that five pediatric patients were colonized (3 rectal swabs, 1 IV catheter and 1 tracheal aspirate) by EfmVRE, and subsequently developed bloodstream infection by the same agent. We also observed a genetic similarity among representative samples of infection and colonization, from the same patient, except the patient 2. Genetic clonal profiles were observed (100% similarity) between samples isolated from patient 1 and patient 5. 95.7% similarity was observed in samples from patient 3 and 90.9% in samples of patient 4. An important fact is that patients 1, 2 and 5 were admitted to the pediatric ICU within two months period, this might explain the genetic similarity observed among the respective isolates. The finding of clonal samples as demonstrated in our study suggests that patients presenting EfmVRE colonization prior to associated risk factors developed infection due to these microorganisms.
Conclusions
It was also observed that there was a high degree of similarity (> 80%) among isolates from different patients and from different hospitals belonging to the same hospital complex. Earlier detection of EfmVRE colonizing patients could prevent its spreading in the hospital. In fact, two vulnerable patients died, one treated for a bloodstream infection with linezolid. Our findings point to the need of studies for EfmVR decolonization in susceptible patient to prevent further infection.