Coagulase-negative staphylococci as true pathogens in newborn infants: a cohort study.

We examined the pathogenicity of coagulase-negative staphylococci (CONS) in newborn infants by comparing presenting nonspecific signs of infection in infants with and without CONS bacteremia. During a 6-month period 799 blood cultures were obtained in a tertiary care nursery; 81 (10.1%) grew CONS and 25 (3.0%) grew other bacteria. A comparison group of 121 infants was selected randomly from ill patients whose blood cultures were negative. In addition 70 well infants were matched to CONS-positive cases. Abnormal clinical signs, complete blood cell counts, C-reactive protein, alpha-1-acid glycoprotein and prealbumin were determined at the time of culture. Signs that discriminated best between infants with and without CONS bacteremia were identified by logistic regression analysis. Infants with CONS bacteremia did not differ from infants with sepsis caused by recognized pathogens, except for lethargy, which was significantly more common in unequivocal infection. Infants with presumed infection but negative blood cultures, and noninfected control patients had abnormal signs significantly less often than CONS-positive infants. C-reactive protein, hyperthermia, increased oxygen requirements and lethargy were the most useful signs in identifying neonatal bloodstream infection. This cohort study provides objective evidence for the pathogenicity of CONS in newborn infants.