Trends in antibiotic resistance among methicillin-resistant Staphylococcus aureus (MRSA) isolates

Methicillin-resistant Staphylococcus aureus (MRSA) has become the most important multidrug-resistant pathogen worldwide, causing significant morbidity and increased healthcare costs. Hospital acquired MRSA are usually associated with increased expression of multiple antibiotic resistance genes. In hospitals, prolonged hospital stay and antibiotic therapy, especially with beta-lactam antibiotics and fluoroquinolones, predispose patients to acquisition of MRSA.

From October 2015 to October 2016. 100 strains of MRSA were isolated from various clinical specimens from different patients. The screening and confirmation of MRSA production was done by Cefoxitin disc diffusion method. Antibiotic susceptibility test for MRSA was done using Kirby-Bauer disk diffusion method for conventional antibiotics.

resistance pattern was Pefloxacin (87%), Ofloxacin (75%), Ciprofloxacin (61%), Erythromycin (65%), Cotrimoxazole (61%), Clindamycin (57%), Cefipime (40%), Tetracycline (29%), Gentamicin (24%), Amikacin (13%), Linezolid (0%), Teicoplanin (0%) and Vancomycin (0%). Inducible clindamycin resistance was 38%. Among risk factors, 74% patients had the history of administration of antibiotics, 70% are Hospitalized patients. 58% of the patients are having foreign bodies in situ. 31% are community acquired and 69% are hospital acquired MRSA.

The selection of antimicrobial agent should be based on in vitro susceptibility and the hospital-based antibiotic policies must be strictly followed. There should be constant surveillance for susceptibility pattern of MRSA as well as to detect emergence of vancomycin resistance. In addition to good infection control practices, the rational use of antimicrobial agents is one of the major steps in reducing the growing problem of antibiotic resistance.