Changing epidemiology of coagulase-negative staphylococci in normal flora of skin.

Coagulase negative staphylococci (CoNS) have recently emerged as important pathogens causing nosocomial blood stream infections. To evaluate the prevalence of CoNS in cutaneous normal flora, skin swabs were collected from voluntary blood donors and processed for culture and identification using matrix assisted laser desorption ionisation-time of flight (MALDI-TOF). CoNS were isolated from 96% of blood donors, most commonly Staphylococcus hominis (86%), followed by Staphylococcus epidermidis (22%) and Staphylococcus haemolyticus (9%). There has been a shift in the prevalent species of CoNS in the community in India, from the earlier known S. epidermidis towards resistant species such as S. hominis and S. haemolyticus. Routine and rapid speciation of CoNS in clinical isolates with MALDI-TOF should be used effectively to manage these resistant species.