Phenotypic determination of specific virulence factors in Staphylococcus aureus circulating at Hyderabad, Pakistan

Abstract

Understanding of virulence characteristics which help Staphylococcus aureusstrains to survive in clinical and non-clinical settings is crucial for antibacterial strategies. This study is designed to investigate some phenotypic virulence traits if they relate S. aureusto defined environment. For this purpose fifty-three S. aureuscultures were isolated from clinical (n=22) and non-clinical (n=31) environments and processed for the determination of selected virulence factors i.e., Staphylokinase, lipase and haemolysins on specific media plates. The results showed that 39.6% (n=21) of total isolates were staphylokinase producers. Categorically the frequency of Staphylokinase producing isolates was higher among the clinicalisolates (50%) than the non-clinical isolates (32.2%). Overall 81% (n=43) isolates were lipase producers. Unequivocally, the frequency of lipase production was higher among clinical isolates (86.3%) than the non-clinical isolates (77.4%). The haemolytic potential was observed in all tested S. aureusisolates. Beta-haemolytic pattern was most frequent observation among both clinical and non-clinical isolates. Interestingly, 81% of Staphylokinase producers showed beta-hemolytic pattern. In conclusion, the current data suggest that S. aureusin clinical setting are more virulent than non-clinical isolates circulating at Hyderabad region