Changing of bloodstream infections in a medical center neonatal intensive care unit.

Background/purpose: Bloodstream infections (BSIs) are associated with high mortality and morbidity in neonatal intensive care units (NICUs). The epidemiology of these infections may change after the application of new infection control policies. The aims of this study are to reveal the changing epidemiology of BSIs in our NICU and inspect the effects of infection control efforts.

Methods: We reviewed and analyzed the clinical characteristics of culture-proven BSIs in our NICU from 2008 to 2013 and compared them with our two previously reported data (1992-2001 and 2002-2007).

Results: The mortality rate decreased from 16.3% in 1992-2001 to 5.6% in 2008-2013. In the recent study period, Gram-positive infections became predominant (58.0%). Coagulase-negative staphylococci remained the most commonly isolated organisms (26.0%). Group B Streptococcus (GBS) BSIs had the highest mortality rate (30.0%). Most GBS-infected infants' mother did not perform prenatal GBS screening. There was a decrease in the total fungal infection rate after fluconazole prophylaxis for very-low-birth-weight (VLBW) neonates, but the infections of fluconazole-resistant Malassezia pachydermatis increased. The incidence of central line-associated BSI increased to 10.6% in 2011. After restricting the catheter duration to <21 days, the incidence decreased to 4.2% in 2013.

Conclusion: Through the years, the overall mortality rate of BSIs in our NICU decreased. Maternal GBS screening is an important issue for avoiding early onset GBS mortality. Fungal infection rate decreased after antifungal prophylaxis policy for VLBW infants, but we should be aware of resistant strains. Restriction of the catheter duration may decrease the incidence of catheter-related BSI.