Etiopatogenia de infecções de corrente sangüínea por Staphylococcus epidermidis associadas e relacionadas ao uso de cateter vascular central em neonatos críticos

Abstract

Bloodstream infections associated/related to central vascular catheters (CVC) at Neonatal Intensive Care Units (NICUs) are frequent, severe and costly. The aim of this research was to evaluate the incidence of bloodstream infection related / associated with different types of CVC and to investigate the pathogenesis of these infections in critical newborns hospitalized in the NICU at the Uberlândia University Hospital. The study was conducted between April/2006 and April/2008. 318 neonates were investigated using CVC followed-up through epidemiologic vigilance National Healthcare Safety Network . Blood specimens were obtained from peripheral puncture. Hemocultures were performed by the automatic commercial system Bactec/ Alert (Vitek System). Additionally, were realized cultures of nostril, skin of CVC insertion site, hub and CVC tip. The ethical approval was obtained from the Ethics Committee of Uberlândia Federal University according to the Health Ministry demands under No. 022/06. The incidence of CVC-associated/related to BSI was 13.0 and 2.1 per 1000 days CVC, respectively. The umbilical catheter (40.6%) and PICC (39.6%) CVCs were used more frequently in times average usage of 5.3 and 13.6 days, respectively. Staphylococcus epidermidis was the most common microorganism (60.0%) in bloodstream infection related CVC, followed by Staphylococcus aureus (30.0%) and Enterococcus faecalis (10.0%). The umbilical catheter was associated with 50.0% of infections related to use of this device. In total, 39.0% and 22.0% of samples from the CVC tip and blood, respectively, showed biofilm production. Approximately 83.0% and 67.0% of blood samples and tip, respectively, isolated cases of CVC-related bloodstream infection were resistant to oxacillin and producing biofilms. The mecA gene was detected in 50.0% of strains of S. epidermidis isolated from blood and CVC tip of the patients with CVC-related infection, and the gene icaAD was detected in the 33.3% and 50.0% of strains isolated from blood and CVC tip, respectively. There was agreement among the clones of S. epidermidis recovered from blood and CVC tip in only one patient, without definition of origin where skin, nostril or hub , due to negative cultures of these places. There is evidence that the pathogenesis of bloodstream infection related to CVC in neonates differs from that reported in adults, and their best knowledge will certainly allow the adoption of practices to prevent and control these infections.