Antibiotic sensitivity pattern of gram negative bacilli isolated from the lower respiratory tract of ventilated patients in the intensive care unit

Background: Lower respiratory tract infections (LRTIs) are the most frequent infections among patients in Intensive care units (ICUs).Aims: To know the bacterial profi le and determine the antibiotic susceptibility pattern of the lower respiratory tract isolates from patients admitted to the ICU.Settings and Design: Tertiary care hospital, retrospective study.Materials and Methods: Transtracheal or bronchial aspirates from 207 patients admitted to the ICU were cultured, identifi ed, and antibiotic sensitivity was performed by standard methods.Statistical Analysis Used: SPSS software was used for calculation of % R of 95% confi dence interval (CI).Results: Of 207 specimens, 144 (69.5%) were culture positive and 63 (30.4%) showed no growth.From 144 culture positives, 161 isolates were recovered, of which 154 (95.6%) were Gram negative bacilli (GNB).In 17 (11.0%)patients, two isolates per specimen were recovered.The most common GNB in order of frequency were Pseudomonas aeruginosa (35%), Acinetobacter baumannii (23.6%), and Klebsiella pneumoniae (13.6%).A very high rate of resistance (80-100%) was observed among predominant GNB to ciprofl oxacin, ceftazidime, co-trimoxazole, and amoxycillin/clavulanic acid combination.Least resistance was noted to meropenem and doxycycline.Conclusion: Nonfermenters are the most common etiological agents of LRTIs in ICU.There is an alarmingly high rate of resistance to cephalosporin and ␤-lactam-␤-lactamase inhibitor group of drugs.Meropenem was found to be the most sensitive drug against all GNB.Acinetobacter and Klebsiella spp.showed good sensitivity to doxycycline. Key words: Antibiotic susceptibility, gram negative bacilli, intensive care unit, ventilated patientsis further complicated by the emergence of multiple beta lactamase producers and multidrug resistant pathogens.In a recent report, Infectious Disease Society of America, specifi cally addressed three categories of gram negative bacilli (GNB), namely extended spectrum beta lactamase (ESBL) producing Escherichia coli, and Klebsiella spp., Multidrug resistant (MDR) Pseudomonas, and carbapenem resistant Acinetobacter spp., as high priority bacterial pathogens.[6] All these major reports indicate the need for obtaining data on prevalent strains in the ICU along with the susceptibility pattern, to help in revising antibiotic policy and guiding clinicians for the better management of patients.Prevalent fl ora and antimicrobial resistance pattern may vary from region to region depending upon the antibiotic pressure in that locality.Therefore, the present study was