Antibiotic Resistance Among Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii Isolates Obtained From Shiraz Nemazi Hospital ICU Wards

Background and Aims: The monitoring of the causative agents of nosocomial infections (Nis), particularly in the Intensive Care Unit (ICU) ward to detect any change in pattern of infection and their resistance profile are crucial. The aim of this study was to investigate the antibiotic resistance pattern among Gram-negative rods isolated from inpatients in different wards of ICU in Shiraz, Iran.
Materials and Methods: In this cross-sectional study from Jaunary to June 2017, 91 different clinical samples were collected from Nemazi teaching hospital ICU wards. After confirming all the isolates by the conventional microbiologic methods, their antimicrobial susceptibility pattern against 11 antibiotics were investigated using the disk diffusion test. Extended-spectrum β-lactamase (ESBL) production was also examined.
Results and Conclusions: The isolated bacteria were Acinetobacter baumannii (n=72, 79.1%), Pseudomonas aeruginosa (n=14, 15.4%), and Escherichia coli (n=5, 5.5%). The highest and the lowest resistance rates were observed against ampicillin (100% and 95.8%) among P. aeruginosa and A. baumannii and imipenem and amikacin (0%) among P. aeruginosa and E. coli isolates, respectively. The frequency of multidrug-resistant (MDR) and ESBL-producing isolates was found 84.6% and 19.8%, respectively. Of the MDR isolates, 23.4% were ESBL producers. A significant difference was determined between ESBL production and MDR isolates.
Regarding the high rate of antimicrobial resistance among clinical isolates in the study area, the antibiotic susceptibility results may be a useful guide for empirical therapy used by physicians.