Slime production as a virulence factor in Staphylococcus epidermidis isolated from bacterial keratitis

A total of 126 coagulase negative staphylococci (CONS) isolated from cornea l scrapings of patients of bacterial keratitis and 50 isolates from healthy eyes (controls) were tested for slime production, Eighty eight (69.84%) of 126 isolates from patients and 11 (22%) of 50 isolates from controls were slime producing (P < 0.001). Of these 88 isolates, 42 were Staphylococcus e pidermidis biotype II, 30 were S. epidermidis biotype I, 8 were S. epidermi dis biotype III and the rest belonged to CONS other than S. epidermidis. Am ongst the corneal ulcer isolates, multidrug resistance (resistance to 3 or more antibiotics) was observed in 82.9 per cent (73/88) slime producing org anisms as against only 18.4 per cent (7/38) nonslime producing organisms (P < 0.001). Similarly, of the total 99 slime positive and 77 slime negative isolates, 79 (79.8%) and 22 (28.6%) respectively were multidrug resistant ( P < 0.001). Although, slime production is known to be one of the major viru lence factors of CONS in extraocular systemic staphylococcal infections, th e present study detected slime in isolates from ocular infections. It was f ound that S. epidermidis I and II were the common biotypes associated with bacterial keratitis and, slime production and multidrug resistance were the two important virulence factors, These observations have clinical and ther apeutic significance.