Plasmid pattern analysis in Slime-producing Coagulase negative Staphylococci in acute bacterial conjunctivitis, keratitis, chronic blepharitis and corneal ulcer

ABSTRACT

Coagulase-negative Staphylococci [CoNS] which are indigenous flora of our skin and mucous membrane were isolated in large numbers from cases suffering from eye diseases as chronic blepharitis, purulent conjunctivitis, suppurative keratitis and corneal ulcer. This study determines CoNS pathogenicity in eye infections in patients at Ophthalmic Centre, Mansoura University. Total of 40 isolates of CoNS from infected eyes and 3 isolates from healthy eyes [control] were identified to the species level using automatic Sensititre, subjected to antibiotic susceptibility testing, Plasmid DNA analysis, B Lactamase production, slime production, and detection of isolates icaA and icaD genes by PCR. S. epidermidis were identified in 79% of isolates. Other species of CoNS were identified in 21% of isolates [P <0.001]. 95% of CoNS were resistant to pencillin and 95% of them were sensitive to vancomycin and teicoplanin. 62.7% were beta-Lactamase producer, 20.9% were Plasmidless. There were10 groups of different plasmid profile and 27.9% contained plasmids of MW 14MDs. 47% of S. epidermidis were potitive for slime production and 52.9% of S. epidermidis were positive ica A and D genes. Slime positive isolates were multidrug-resistant as compared to slime negative isolates [P <0.001]. Slime-producers possessed multiple plasmids in contrast to no slimeproducers [P<0.001]. Plasmid of MW14MDs had correlation with slime producer and with multidrug resistance isolates [P =0.04]. So 14MDs plasmid could determine virulence of isolates