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.

  • Hamzullah Khan Nowshera Medical College, Nowshera.
  • Fazli Bari Nowshera Medical College Nowshera.
  • Tayyaba Basharat Nowshera Medical College Nowshera.
  • Saadullah - Sarhad University, Peshawar.
  • Shabbir Hussain Nowshera Medical College Nowshera.
Keywords: Antibiotic Resistance, D-Test Phenomenon, ERM Gene Encoding Methylase, Macrolide-Lincosamide-Streptogramin-B Antibiotics


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.

Author Biographies

Hamzullah Khan, Nowshera Medical College, Nowshera.

MBBS, M.Phil

Associate Professor Hematology

Fazli Bari, Nowshera Medical College Nowshera.

MBBS, M.Phil

Professor of Microbiology

Tayyaba Basharat, Nowshera Medical College Nowshera.

MBBS, M.Phil

Assistant Professor of Pharmacology


Saadullah -, Sarhad University, Peshawar.

Director Public Health


Shabbir Hussain, Nowshera Medical College Nowshera.


Assistant Professor Medicine