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Nosocomial Infections and Drug Susceptibility Patterns in Methicillin Sensitive and Methicillin Resistant

Nitish Kumar Sharma1, Raina Garg, Shrikala Baliga

  • 1Intern, Department of Microbiology, Kasturba Medical College , Mangalore, India .

Journal of Clinical and Diagnostic Research : JCDR
|December 4, 2013
PubMed
Abstract

Insights

Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA) exhibit distinct antibiotic susceptibility patterns. Vancomycin remains effective against MRSA, while penicillin shows low susceptibility for both strains.

Area of Science:

  • Medical Microbiology
  • Infectious Diseases
  • Antimicrobial Resistance

Background:

  • Staphylococcus aureus is a major cause of hospital-acquired infections.
  • Antibiotic resistance in S. aureus, particularly MRSA, poses a significant clinical challenge.
  • Understanding susceptibility differences between MRSA and MSSA is crucial for effective treatment.

Purpose of the Study:

  • To determine and compare the antibiotic susceptibility patterns of nosocomial Methicillin-Sensitive S. aureus (MSSA) and Methicillin-Resistant S. aureus (MRSA).

Main Methods:

  • Isolation and identification of S. aureus using standard microbiological techniques.
  • Identification of MRSA strains via the cefoxitin disk diffusion method.
  • Antibiotic susceptibility testing performed using the Kirby-Bauer disk diffusion method, interpreted per CLSI guidelines.

Main Results:

  • Out of 685 S. aureus strains, 173 (25.25%) were MRSA and 512 (74.25%) were MSSA.
  • All MRSA and MSSA isolates were susceptible to vancomycin; penicillin showed the lowest susceptibility.
  • MRSA demonstrated significantly higher resistance to clindamycin, ciprofloxacin, cotrimoxazole, erythromycin, and tetracycline compared to MSSA.

Conclusions:

  • Nosocomial infections caused by MRSA represent a substantial public health concern.
  • Significant differences exist in antibiotic susceptibility between MRSA and MSSA.
  • Vancomycin is effective against all studied MRSA isolates; judicious antibiotic selection based on susceptibility testing is vital for treatment and resistance prevention.
Keywords:
Drug SusceptibilityMethicillin-Resistant Staphylococcus aureusNosocomial Infections

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