mecA and fdh: markers of pathogenicity and commensalism in Staphylococcus epidermidis of pediatric origin from Pakistan

Staphylococcus epidermidis is an opportunistic bacterial pathogen. The study screened isolates of S. epidermidis of pediatric origin for genetic markers of discriminatory potential. 103 isolates (n = 75 clinical; n = 28 community) were screened for methicillin resistance (mecA), formate dehydrogenase (fdh) and an array of virulence factors through multiplex PCR and Congo red assay. The isolates were typed in four distinct categories, based on the presence of selected virulent factors. The type A clinical isolates carrying icaADBC operon (n = 22; 29.3%, P = 0.117) were not significantly differentiating the origin of isolates. The type B clinical isolates representing methicillin resistant S. epidermidis (MRSE) (n = 73; 97.3%, P < 0.00001) and the type C clinical isolates lacking formate dehydrogenase fdh (n = 62; 82.6%, P < 0.00001) were having significant discriminatory potential of clinical isolates, respectively. All type D community isolates were carrying fdh (n = 28; 100%, P < 0.00001). MecA and fdh are significant differential markers of pathogenicity and commensalism in S. epidermidis of pediatric origin.