Analysis of antimicrobial resistance for Staphylococcus aureus strains by WHONET 5: Microbiology laboratory database software

Abstract

Objectives: To analyze our hospital laboratory microbiological data by using WHONET 5-Microbiology laboratory database software-, and to acquire information about antimicrobial resistance of Staphylococcus aureus strains among every ward. Materials and methods: The database of Staphylococcus aureus strains had been brought to our hospital microbiology laboratory from every ward in our hospital from September 2001 till December 2002. Analysis was performed under the condition as one isolate per one patient. Starting of 'resistance profile' analysis in WHONET 5 and analyzing the microbiological laboratory testing reports for every ward. We chose Oxacillin, Levofloxacin, Erythromycin and Gentamicin as the antimicrobials that need to be investigated for resistance. We evaluated the monthly transition of resistance ratios with regard to the specific wards that have the moving lines of inpatients in order to verify the hypothesis that resistant strains may be carried from ward to ward along the moving lines of inpatients. Results: The data of 2,113 Staphylococcus aureus strains were accumulated and analyzed. Overall Oxacillin resistance ratio in our hospital was 65.7%. The ward of the smallest Oxacillin resistance ratio was Pediatrics/Ophthalmology ward. The ratios of Oxacillin resistant were varied as from 67.9% to 96.7% regardless the categories of wards such as internal medicine or surgery. Multi-resistant MRSA strains were overwhelmingly dominant in the wards of surgery. The ratios of the Gentamicin sensitive strains that were resistant to Oxacillin were high over the every ward. The moving lines of inpatients existed between ICU/CCU ward and three rear wards. Two rear wards whose Oxacillin resistance changes were reflected to those of ICU/CCU, but one rear ward was not. Conclusion: Variation of resistant degree among wards were very obvious and large. We could survey the wards where patient-to-patient transmission of resistant organisms might occur along the moving lines of inpatients. WHONET 5 will be recognized as an analysis and surveillance tool for every infection control team to survey the suspicious wards.