Neonatal Nosocomial Bloodstream Infections at a Referral Hospital in a Middle-income Country: Burden, Pathogens, Antimicrobial Resistance and Mortality

Background: Data on nosocomial bloodstream infection (BSI) rates, pathogens, mortality and antimicrobial resistance in African neonates are limited.

Methods: Nosocomial neonatal BSI at Tygerberg Hospital, Cape Town were retrospectively reviewed between 1 January 2009 and 31 December 2013. Laboratory and hospital data were used to determine BSI rates, pathogen profile, mortality and antimicrobial resistance in selected nosocomial pathogens.

Results: Of 6521 blood cultures taken over 5 years, 1145 (17.6%) were culture-positive, and 717 (62.6%) discrete nosocomial BSI episodes were identified. Nosocomial BSI rates remained unchanged over time (overall 3.9/1000 patient days, 95% CI 3.6-4.2, χ(2) for trend P = 0.23). Contamination rates were relatively high (5.1%, 95% CI 4.6-5.7%). Among BSI pathogens, Gram-negatives predominated (65% vs 31% Gram-positives and 4% fungal); Klebsiella pneumoniae (235, 30%), Staphylococcus aureus (112, 14%) and Enterococci (88, 11%) were most prevalent. Overall crude BSI mortality was 16% (112/717); Gram-negative BSI was significantly associated with mortality (P = 0.007). Mortality occurred mostly in neonates of very low (33/112, 29%) or extremely low (53/112, 47%) birthweight. Deaths attributed to nosocomial BSI declined significantly over time (χ(2) for trend P = 0.01). The prevalence of antibiotic-resistant pathogens was high: methicillin-resistant Staphylococcus aureus 66%, multidrug-resistant A. baumanni 90% and extended-spectrum β-lactamase-producing K. pneumoniae 73%.

Conclusion: The burden of nosocomial neonatal BSI at this middle-income country referral neonatal unit is substantial and remained unchanged over the study period, although attributable mortality declined significantly. Nosocomial BSI pathogens exhibited high levels of antimicrobial resistance.