Little has been published about the occurrence,
speciesidentification, andpathogenicpotentialofcoagulasenegative
staphylococci (CoNS) present in drinking water. In
this study, ten species were identified among 57 isolates
of staphylococci from 756 samples of chlorinated drinking
water taken from public distribution networks in the Slovak
Republic. S. warneri (37%), S. haemolyticus (23%), and S.
saprophyticus ssp. saprophyticus (14%) were identified
most frequently. Isolates did not produce coagulase,
DNase, or hyaluronidase; production of gelatinase and
lecithinase was observed in 28 and 22 isolates, respectively.
Genetically encoded ability for production of enterotoxin
SED was revealed in two isolates. Among ten antibiotics
tested, resistance to ampicillin (66.7%), penicillin (64.9%),
and erythromycin (57.9%) were observed most frequently.
Resistance to gentamicin, vancomycin, or clindamycin was
not confirmed. Production of β-lactamase was observed
in 64.9% of isolates. Fourty-two isolates were resistant to
two or more antibiotics tested, and eight isolates showed
multiresistance. The presence of mecA gene was confirmed
in 8 isolates, while PBP2a was revealed in 7. Two isolates of S.
epidermidis were identified as methicillin-resistant (MRSE).
The results demonstrate that CoNS in chlorinated drinking
water may possess virulence factors and show resistance to
various antibiotics. Therefore, their pathogenic potential
should not be ignored.