Background Coagulase negative Staphylococci (CoNS) are the commonest organisms recovered from neonates with late onset sepsis in the neonatal intensive care unit. CoNS are normal skin commensals and vary in species, antibiotic susceptibility and pathogenicity.¹ Clinically defining true CoNS bacteraemia is challenging. Management of these infections varies between clinicians, affecting antimicrobial consumption and bacterial resistance long-term.

Methods Infants with CoNS bacteraemias were identified at Heartlands Hospital, Birmingham, UK between 07/01/12 and 04/01/13. Demographic and clinical data were collected, using published tools.² CoNS were identified using molecular methods, and vancomycin susceptibility was measured by culture. Antibiotic duration was utilised as an outcome.

Results 96 blood cultures were positive for CoNS (44 S. epidermidis, 48 CoNS (non-S. epidermidis); 1 mixed CoNS and 3 mixed organisms). These were collected from 60 neonates, representing 76 suspected sepsis episodes. 37/76 episodes were true bacteraemias. 44.4% of S. epidermidis and 52.5% of non-S. epidermidis met the true bacteraemia criteria. Median antibiotic duration was the same for S. epidermidis episodes whether they were true bacteraemias or not (7 days). Antibiotic duration for non-S. epidermidis episodes was 7 days for true bacteraemias and 6 days for contaminants.

Discussion Determining whether CoNS, isolated from a neonatal blood culture, are significant should be made clinically. Our data suggests clinicians are not adjusting antibiotic duration according to published clinical definitions, as duration was similar for true bacteraemias and contaminants. Early identification of specific organisms in combination with a clinical definition of true bacteraemia could have significant implications on antibiotic stewardship.

References

1. Healy CM, Baker CJ, Palazzi DL, et al. Distinguishing true coagulase negative Staphylococcus infections from contaminants in the neonatal intensive care setting. J Perinatol. 2013;33(1):52–8

2. Modi N, Doré CJ, Saraswatula A, et al. A case definition for national and international neonatal bloodstream infection surveillance. Arch Dis Child Fetal Neonatal Ed. 2009;94:F8–F12