Virulence Characterization of Coagulase-Negative Staphylococci Isolated from Sexually Active Women with Symptomatic Genital Tract Infection, In Comparison with Staphylococcus aureus Isolated from the Same Cases

Abstract

This study included 33 coagulase-negative staphylococci (CNS) and 35 Staphylococcus aureus isolated from sexually active females with symptomatic genital tract infection (64 pregnant and 110 non-pregnant). Comparison of phenotypic characteristics showed that the difference is not significant between CNS and S. aureus isolates for hemolytic activity (63.6% and 54.2%, respectively); lipolytic activity (87.8% and 88.5%, respectively); protease production (18.1% and 31.4%, respectively). and biofilm formation ( 96.9% and 94.2%, respectively). Whereas the difference is significant (P≤ 0.05) for urease production (18.1% and 42.8%, respectively). With the exception of lipolytic activity and biofilm formation, co-expression of other factors showed that there was an opposite expression of hemolytic and proteolytic activities of both CNS and S. aureus isolates. For CNS only 3/33 (9%) of the isolates were hemolytic and preoteolytic while for S. aureus only 2/35 (5.7%) isolates had this characteristics. Also for S. aureus isolates, ureolytic activity was more correlated with hemolytic (20%) and proteolytic (11.4%) activities than in CNS (6.0% and 3.0%, respectively). We concluded that, for this study included factors, the virulence of CNS isolated from females' genital tract infection is comparable to that of the potential females' genital tract pathogen, S. aureus. So that, CNS can be opportunistic pathogens in these cases rather than mere contaminants.