Zeitschrift für Arzneimittelstoffwechsel und Toxikologie
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Abstrakt

Multi-Drug Resistance of MRSA Isolated Strains from Healthcare, Community and the Distribution of Fusidic Acid MIC and Zone of Inhibition

Said E Wareg

The evolution of resistance to antibiotics is one of the most significant problems in Modern medicine, posing serious threats to human and animal health. Multidrug-resistant organisms(MDRO,S), including MRSA, vancomycin-resistant Enterococci (VRE)and certain Gram-negative bacilli  have important infection control complications. From a previous study, an agar susceptibility testing was used  to test all isolates against  vancomycin, chloramphenicol, gentamicin, fusidic acid, erythromycin, streptomycin, Ciprofloxacin, cefotaxime and clindamycin.

MRSA was detected using cefoxitin (30µg) disc and antibiotic susceptibility pattern was determined using the Kirby and Bauer disc diffusion susceptibility testing method and confirmed for fusidic acid and vancomycin by determination of minimum inhibitory concentration. The isolated MRSA strains showed multiple drug  resistance pattern as 42% for IPHA-MRSA, 34% for OPHA-MRSA and 23% for   CC-MRSA. The distribution of strains of IPHA, OPHA and CC-MRSA compared with the MIC and zone size of fusidic acid showed that the highest number of isolates were distributed about the highest MIC values for IPHA-MRSA(16 , 8 , 4mg/L) ,OPH-MRSA (8, 4,2mg/L) and CC-MRSA(8,4mg/L). These results showed high multi-drug resistance for all MRSA isolated strains ( Fig.1, Fig.2, Fig.3). Interpretative zone of inhibition for fusidic acid and vancomycin was based on the British Society for Antimicrobial Chemotherapy (BSAC) (Anon-2010/2013) guidelines.  Standard international interpretation criteria for zone size for fusidic acid should be addressed.