Prevalence Of Methicillin-Sensitive And Methicillin-Resistant Staphylococci In Intensive Care Units In A University Hospital

Abstract

Aim: The intensive care units (ICUs) are burdened with a high frequency of nosocomial infections often caused by multiresistant nosocomial pathogens. Coagulase-negative staphylococci (CoNS) and Staphylococcus aureus are reported as important causative agents of nosocomial infections. The objective of this study was to identify frequency of methicillin resistant and susceptible staphylococci from the various clinical samples in ICUs, and to investigate resistance patterns against various antibiotics used broadly for treatment. Methods: Originating from four selected ICUs and burn center in a University hospital, a total of 241 staphylococci strains from blood, respiratory tract, urine and wound sites were processed in our central laboratory to assess their occurrence rates and antimicrobial susceptibility profiles. Susceptibility tests of isolates were performed according to disc diffusion method recommended by National Committee for Clinical Laboratory Standards (NCCLS). Results: Staphylococci strains were isolated from 40.4% of the patients in ICUs. The rates of methicillin resistant and susceptible Staphylococcus aureus were 24.1% and 9.96%, respectively. Out of 241 isolates, 14.5% methicillin sensitive CoNS and 15.8% methicillin resistant staphylococci were isolated. The highest staphylococci isolation (47.3 %) was obtained in cardiovascular surgical ICU which is followed by general surgical ICU (45.1%), burn center (39.8%), coronary ICU (39.4%) and internal ICU (33.9%). There is statististically significant difference between surgical ICU and internal ICU. None of the isolated staphyloccocci showed resistance against vancomycin. Penicillin resistance was found to be 100% in methicillin resistant Staphylococcus aureus strains while it was 76% in methicillin sensitive Staphylococcus aureus. There is significant difference between two groups. Conclusion: Frequency of staphylococci was found to be high in patients treated at intensive care units. Antibiotic resistance patterns of methicillin resistant Staphylococcus aureus strains were found to be quite higher than that of methicillin susceptible staphylococcci.