Introduction & Objective: Nosocomial pneumonia is pneumonia that occurs at least 48 hours after hospitalization. In total, this infection is the second most common cause of hospital-acquired infection in intensive care units. The purpose of conducting this research was the detection of etiology of nosocomial pneumonia in the ICUs of teaching hospitals of Hamadan University of medical sciences.

Materials & Methods: In this cross -sectional study, 353 patients hospitalized in the ICUs of Hamadan hospitals (Besat and Ekbatan) were analyzed. Different variables including age, gender, cause of hospitalization and underlying diseases were recorded in a number of questionnaires. On repeated visits to the ICUs, these questionnaires were completed for different patients and in the next weekly visits the patients’ conditions and paraclinical aspects were recorded in the files. The criteria for onset of nosocomial pneumonia was the appearance of fever after 48 hours and leukocytosis, the increasing pulmonary secretion and the alteration of chest x-ray together with the culture results of secretions obtained by suction of tracheal tube. In the case of infecting with nosocomial pneumonia some more variables including connecting a ventilator, the period of connecting the ventilator until infection, the type of consumed antibiotic before the onset of nosocomial pneumonia, the obtained organisms, and the period of hospitalization in the ICU until infection were also recorded for these patients. The chi-square test and Fisher’s exact test were used for data analysis and the meaningful levels for the tests were less than 0.05.

Results: The average age of study population was 51.2 years with the standard deviation of 21.9 years . 36 people (10.2%) of the hospitalized patients in the ICUs were infected with nosocomial pneumonia. Trauma with a rate of 47.5% (168 people) was the most common cause of patient hospitalization in the ICUs. 66.5% of these patients (24 patients) were affected by nosocomial pneumonia (VAP) after connecting to ventilation device . In 91.7% of the cases, the hospitalized patients in the ICUs consumed antibiotics, out of which 50% were treated with cephalosporins. It is also necessary to note that 42.5% of patients took more than one type of antibiotics.

Conclusion: The findings of this study indicates the high consumption of cephalosporins, a predisposing factor to nosocomial infections, in the ICUs of teaching hospitals of medical university of Hamadan . On the other hand,the consumption of floroquinolones were less compared to the findings of other similar researches.