Species identification & methicillin resistance of coagulase negative staphylococci from clinical specimens.

A total of 75 strains of coagulase negative staphylococci were isolated in pure culture from different specimens from patients suffering from various deep seated staphylococcal infections undergoing treatment between November, 1985 and December, 1986. Using the Baird Parker classification system, Staphylococcus epidermidis was the commonest isolate found (60%) of which biotype 1 was the most frequent (51.1%). Twenty seven (36%) untypable strains could be typed using Kloos and Schleifer's classification system. These strains were identified as Staph. cohnii (10), Staph. hominis (8), Staph. capitis (4), Staph. haemolyticus (3), Staph. simulans (1), and Staph. warneri (1). Three Staph. saprophyticus strains were isolated from patients of urinary tract infection. Methicillin resistant strains (14.6%) were isolated mainly from patients of meningitis, urinary tract infections and endocarditis. All these strains were sensitive to vancomycin. Coagulase negative staphylococci thus can cause a number of human infections and should no longer be regarded as harmless commensals.