Phenotypic detection of ERM gene encoding methylase responsible for resistance to macrolide, lincosamide-streptogramin–B (MSL-B)antibiotics in methicillin sensitive and methicillin resistant staph aureus infections.
Objectives: Phenotypic Detection and sensitivity pattern of erm gene/D-Test positive Methicillin Sensitive (MSSA) and Methicillin Resistant Staphylococcus Aureus (MRSA). Study Design: Prospective Cohort study. Setting: Department of Pathology at Qazi Hussain Ahmed Medical Complex Nowshera. Period: From 1st March 2019 to 30th Sept 2019. Material & Methods: Relevant information’s were entered in a SPSS version 16 for descriptive and inferential analysis of different variable. Results: Out of 186 patients Staph Aureus isolates, 52(27.95%) showed D-test Positive. Thirty (57.7%) cases were females and 22(42.3%) males. The Mean age with Standard Deviation was 28.36+3.8 years. In 45(86.5%) cases D-Test phenomenon was observed in MRSA while in 7(13.5%) cases in MSSA. Chi-square test showed a significant correlation in gender groups for acquiring resistance to Macrolide-Lincosamide-Streptogrammin-B (MLS-B) antibiotic (p = 0.07) by expressing erm gene encoding methylase. The probability of resistance in female gender are 4.5 times more as compared to male gender (p=0.09, OR=4.53). The sensitivity pattern to D+ MRSA was; Vancomycine 100%, Lanezolid 100%,Rifampicin 84.23%, Fusidic acid 55.77%, Doxycyclin 32,59%, levofloxacin 21.15%, Gentamycine13.46%, ciprofloxacin 13.46%. It is pertinent to mention that the sensitivity to cefoxetin (Beta lactam antibiotics) was seen only in cases with D+MSSA cases only (13.5%) cases. Conclusion: D-Test phenomenon can be seen in both MRSA & MSSA infections. D+MSSA cases where sensitive to b-lactam antibiotics shall be treated with b-lactams only, and precious drugs like Vancomycine & Lanezolid should be kept reserved for D+ MRSA cases to reduce resistance.