RESUMEN
The causative organisms vary according to the patients’ demographics in the ICU, methods of diagnosis, the durations of hospital and ICU stay. It is necessary to study different etiological organisms and their antimicrobial susceptibility pattern for generating local antibiotic policy. Aims: To study the causative organisms and determine the antibiotic susceptibility pattern of the lower respiratory tract isolates from patients admitted to ICU. Methods and Material: Endotracheal aspirates from 200 patients admitted to the ICU were cultured, identified and antimicrobial susceptibility testing was performed by standard methods. Results: From 200 specimens, 69(34.5%) were culture positive. Total 96 isolates were recovered, from these 92 (96.87%) isolates were gram negative bacilli (GNB). In 34.78% specimens, two isolates were recovered. The most common Gram- negative organism being Acinetobacter spp. (31.25%) followed by Klebsiella spp. (21.87%), E-coli (21.87%) and Pseudomonas Spp. (17.7%). All GNBs were 100% sensitive to polymyxin B and colistin and resistant to piperacillin, ceftazidime and cotrimoxazole. 50% E-coli and 38% of Klebsiella pneumoniae strains were ESBL (extendedspectrum b-lactamase) producers. Conclusions: This study demonstrates the trend in antimicrobial susceptibility pattern of gram negative bacilli in intensive care unit. It is the most important for specific treatment of ventilator associated pneumonia patients and to generate local data periodically to decide empiric antimicrobial therapy.