The Susceptibility Evaluation of Multiresistant Gram-Negative Bacilli to Meropenem and Imipenem

Introduction: Nosocomial infections are responsible for the much of the morbidity and mortality found in hospitals. The present study was conducted on 70 bacterial strains isolated from hospitalized patients in various medical units of Baqiyatallah Hospital in Tehran, Iran during a period of 12 months from; March to February 2009. Methods: The bacterial sensitivity for meropenem and imipenem was evaluated using the E-test and explanations of the MIC values. All patients were included in this study that had been hospitalized with no signs and symptoms of infection within the first 48 hours of hospitalization and began presenting signs and symptoms of infection after 48 hours of hospitalization. Results: Resistance to meropenem and imipenem was confirmed with E-test (AB Biodisk, Sweden) and disc diffusion methods. Meropenem and imipenem were active against 61 (64.2%) and 62(65.2%) strains, respectively, of the 95 ESBL positive strains. Conclusion: The activity of meropenem or imipenem against gram negative ESBL-positive bacilli is decreasing rapidly but even so these antibiotics are effective against nosocomial multiresistant organisms.