Nosocomial Gram-positive antimicrobial susceptibility pattern at a referral teaching hospital in Tehran, Iran

Aims: The aim of the study was to evaluate epidemiology and susceptibility patterns of nosocomial Gram-positive infections in a referral teaching hospital. Methods: Over a 1-year period, Gram-positive microorganisms isolated from specimens of hospitalized patients with documented nosocomial infection underwent antimicrobial susceptibility testing using the disk diffusion test. In addition, possible risk factors for developing multidrug-resistant bacteria were evaluated. Results: During the study period, a total of 137 nosocomial infections were detected. Staphylococcus aureus was the most frequently isolated microorganism (56.2%), followed by Enterococcus spp. (21.9%) and Staphylococcus epidermidis (15.3%). All S. aureus strains were sensitive to vancomycin, teicoplanin, linezolid and chloramphenicol. More than 50% of enterococci strains were resistant to vancomycin and teicoplanin. Possible risk factors for multidrug resistance among isolated pathogens were history of antibiotic use and intubation of patient for mechanical ventilation. Conclusion: This study showed high rates of antimicrobial resistance among nosocomial Gram-positive pathogens, complicating antibiotic therapy and its outcomes.