[Clinical significance of coagulase-negative staphylococci isolated from neonates].

Abstract

To evaluate the clinical significance of coagulase-negative staphylococci (CNS) isolated from newborns' infections at Neonatal Unit of Hospital das Clínicas da Faculdade de Medicina de Botucatu.
The CNS strains isolated were identified and classified as clinically significant and contaminant, based on a series of clinical and laboratory data obtained from patients who stayed in the Neonatal Unit. The following data were analyzed: risk factors for infections, clinical evolution, abnormal blood cell counts and/or C-reactive protein and antibiotic therapy.
Among the 117 CNS strains isolated, 60 (51.3%) were classified as significant and 57 (48.7%) as contaminant. Among the 54 infants infected by CNS, 43 (79.6%) presented very low birthweight (<1,500 g). Most of the infants infected by CNS were submitted to two or more invasive procedures (77.8%), including use of catheter (88.9%), parenteral nutrition (64.8%) and mechanical ventilation (61.1%). Staphylococcus epidermidis was the most frequently isolated species (77.8%) and more often associated with infection (86.7%) than with contamination (68.4%). Other species of CNS, including two strains of S. haemolyticus, three strains of S. lugdunensis, one strain of S. simulans, one strain of S. warneri and one strain of S. xylosus were also isolated from infants with clinical evidence of pneumonia, necrotizing enterocolitis and sepsis.
Most newborns infected by CNS presented important risk factors for infection onset, including birthweight <1,500 g, foreign body presence and previous use of antibiotics. The identification of CNS species constitutes a useful marker of infection, since S. epidermidis was the species more frequently associated with infection.