Study of Methicillin-resistant Staphylococcus aureus Isolated from Various Clinical Specimens from Tertiary Care Hospital

Abstract

ABSTRACT Introduction: Staphylococci are Gram-positive bacteria, with a diameter of 0.5–1.5 μm and individual cocci, which are divided in more than one plane from the grape-like cluster. In the genus staphylococci, 32 species and 8 subspecies are present in many of which are present as a commensal in the human body. Staphylococci are frequently found as a normal flora of skin mucosal, surface of respiratory, upper elementary, and urogenital tract of the human body. In immunocompromised condition, the infection can be spread by skin-to-skin contact and also by excretion such as saliva aerosol releasing during sneezing and coughing. Infection of staphylococci may also spread from the animal product such as nonpasteurized milk and milk products. Over the last few decades, Staphylococcus aureus has emerge as the most dangerous organism, which is known as methicillin-resistant S. aureus (MRSA). Some strains show vancomycin resistance by S. aureus in hospitalized patients. The present study was conducted to study the prevalence and antibiogram of MRSA isolates in a clinical sample from Acharya Vinoba Bhave Rural Hospital. Materials and Methods: This study was conducted in the Department of Microbiology at Jawaharlal Nehru Medical College (Datta Meghe Institute of Higher Education and Research), Wardha, from August 2020 to December 2021. The samples received in the microbiology laboratory were inoculated on blood agar and MacConkey’s agar, and incubated for 24 h at 37°C for staphylococcal isolation. A total of 145 Staphylococcal aureus were isolated and confirmed by Gram stain and various biochemical tests such as catalase test, oxidase test, coagulase test, and mannitol salt agar. Antibiotic susceptibility test was examined on the Mueller–Hinton agar plate using the modified Kirby–Bauer disc diffusion method. Screening of methicillin resistant was performed by cefoxitin (30 μg) disc diffusion method and interpreted according to CLSI guideline. Results: The prevalence of MRSA was 76 (52.41%) to methicillin-susceptible S. aureus. The highest MRSA was found in the age group >50 years (26.31%). Out of 76 MRSA isolates from different departments, the medicine and orthopedic departments show maximum MRSA as 19.74% each followed by pediatrics (17.11%) and surgery (13.16). Out of 76 MRSA isolates, vancomycin showed 93.42% sensitivity followed by linezolid (85.52%), Gentamicin (71.05%), tetracycline (56.57%), clindamycin (46.05%), and erythromycin (31.57%). Conclusion: With the advancement of new therapeutic agent, MRSA is also being easily resistant. Due to increasing cases of MRSA, there is an increase in the rate of morbidity and mortality. Moreover, except vancomycin, other drugs are resistant, as their MIC is not in the susceptible range. Thus, the results of this study indicate that vancomycin is a suitable medication to take when MRSA cases rise. In such cases, MRSA can be controlled by regular monitoring and checking the irrational use of antibiotics.