Prevalence of coagulase negative Staphylococcus species among hospital personnel and surgical patients.

Two hundred and fourteen strains of Coagulase negative Staphylococci (CNS) isolated from hospital personnel (114 strains) and patients (100 strains) were identified upto species level. The prevalence rate of CNS in relation to sex, sources and type of specimens were analysed. Most of the CNS strains belonged to S. epidermidis (49.1% among carriers and 39% in clinical isolates) and S. hominis (36% each). Besides, five more CNS species, namely S. saprophyticus, S. capitis, S. haemolyticus, S. cohnii and S. xylosus were also isolated. (0.5 to 10.3% isolation rates). Maximum S. hominis isolated were from hospital personnel and urine from patients (63.4% and 72.2%, respectively), 50.0% and 33.3% of S. hominis were found from urine and blood, respectively. The present study revealed that the leading species S. epidermidis and S. hominis may play an important role in the nosocomial infections, especially among immunocompromised hosts during their hospital stay.

Correlation between beta-lactamase production and MIC values against penicillin with coagulase negative staphylococci.

Two hundred strains of coagulase negative staphylococci (CNS) isolated from various clinical specimens (116) and healthy hospital personnel (84) were investigated for the production of beta-lactamases by means of three iodometric techniques and correlated with the minimum inhibitory concentration (MIC) values of penicillin-G by agar dilution technique and disc diffusion technique. One hundred and fifty (75.0%) of the 200 strains tested produced beta-lactamases. Seventy two per cent of the CNS were found to be beta-lactamase positive by the starch paper technique which was the most sensitive one in our study. The MIC values of penicillin against CNS ranged from less than or equal to 1.25 to greater than or equal to 2000 units. The present study indicated the higher prevalence of beta-lactamase producers with increased penicillin resistance among CNS strains isolated from healthy carriers and hospitalised patients.