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

The aim of the study was to evaluate epidemiology and susceptibility patterns of nosocomial Gram-positive infections in a referral teaching hospital.

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.

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.

This study showed high rates of antimicrobial resistance among nosocomial Gram-positive pathogens, complicating antibiotic therapy and its outcomes.