Staphylococcus haemolyticus disseminated among neonates with bacteremia in a neonatal intensive care unit in Rio de Janeiro, Brazil

Oxacillin-resistant Staphylococcus haemolyticus (ORSH) was found as the most prevalent (77.5%) species of coagulase-negative staphylococci associated with bacteremia in neonates making use of intravenous catheters in an intensive care unit of a Brazilian teaching hospital. Thirty-one blood isolates were confirmed as S. haemolyticus by sequencing of the 16S and clustered in 6 pulsed-field gel electrophoresis types (with 58% of the strains belonging to 2 predominant types B and D). S. haemolyticus was mostly oxacillin-resistant (90.3%) displaying multiresistance profiles (70.4%). However, the mecA gene was undetected in 22.6% strains. ORSH exhibited slime production on Congo-Red agar (67.7%), adherence to polystyrene (96.7%), and glass (87%) surfaces. Interestingly, ica-operon was detected in 58% strains, mostly belonging to the B, D, and F genotypes, which is a significantly higher percentage when compared to other studies conducted at different parts of the globe. Data indicated that ica operon and biofilm-forming ORSH are endemic in Brazilian nosocomial environment.