Detection of high levels of resistance to antimicrobials including Linezolid and Vancomycin in Staphylococcus aureus

Abdul Haque

doi:10.21767/2472-1093-C2-006

Detection of high levels of resistance to antimicrobials including Linezolid and Vancomycin in Staphylococcus aureus

6^th Edition of International Conference on Antibiotics, Antimicrobials and Resistance

October 11-12, 2018 Edinburgh, Scotland

Abdul Haque

The University of Faisalabad, Pakistan

Posters & Accepted Abstracts: J Infec Dis Treat

Abstract:

Both MRSA (Methicillin resistant Staphylococcus aureus) and MSSA (Methicillin sensitive Staphylococcus aureus) are rapidly overcoming the current array of drugs. Two hundred isolates from a hospital were studied for resistance to 27 drugs representing various generations of 11 groups. Important findings were substantiated by targeting of genetic loci. Seventy two (36.0%) isolates were MRSA. Antimicrobial sensitivity results were obtained by disc diffusion method and E-test. Generally, these isolates were resistant to almost all β-lactams, fluoroquinolones, and aminoglycosides. Oxacillin, Ofloxacin, Ceftazidime, Meropenem, Aztreonem, and Gentamicin were significantly more active against MSSA. Both MRSA and MSSA showed high level of resistance towards Linezolid, figures being 41.6% and 12.5% respectively. Vancomycin resistance was remarkable in MRSA (12.5%) but relatively low in MSSA (4.7%). The cfr gene was detected in 80% Linezolid resistant isolates and vanA locus in 76% Vancomycin resistant isolates. This level of resistance against Linezolid and Vancomycin is unprecedented. There were 8 MRSA isolates which were phenotypically resistant to all drugs. None of MRSA isolates showed less than 60% resistance to tested drugs and all were MDR. Among the MSSA isolates, 65% were MDR. These results are alarming and highlight the threat of non-treatable Staphylococcus aureus strains. We also studied the leading virulence factors associated with these pathogens. α-toxin, the major cytotoxic factor, was detected in 40% whereas ß-hemolysin was found in 25% cases. Panton Valentine leucocidin was detected in 8.33% and toxic shock syndrome toxin in5% cases. Two multiplex PCRs were developed which when run simultaneously can provide vital information about methicillin resistance and virulence status of the isolate within a few hours as compared to several days needed by routine procedures.