Abstract
Objective: To determine the susceptibility pattern of Enterobacteriaceae isolated from different body sites against Imipenem
Methodology: We conducted a retrospective analysis of the susceptibility pattern of
Enterobacteracaea against Imipenem, isolated from clinical specimens
between April 2014 to July 2017 at Rawal General and Dental hospital, Islamabad, Pakistan.
Results: A total of 575 Enterobacteriaceae were isolated from
urine, pus and other specimens. These specimens were taken from 163 males
and 412 females. The ages of patients ranged from 1 to 80 years.
Escherichia coli was among the most common isolate from all the specimens
(n=359), followed by Klebsiella pneumoniae (n=92) and Enterobacter cloacae
(n=51). Among the total isolates (n=575), 90.78% (n=522) were
susceptible to Imipenem. Isolates from urine revealed 95.52% susceptibility
against Imipenem which was significantly higher than the pus (74.22%) and
other specimens isolates (83.01%) susceptibility against Imipenem(p<0.0001).
Conclusion: The site of isolation appears to have a significant effect on the susceptibility of bacteria to Imipenem. This factor should be taken into account when considering antibiotic resistance. Overall Imipenem resistance (Carbapenemase Resistance Enterobacteriaceae) was less than 10% among Enterobacteriaceae in our set up. This resistance was lowest among
Enterobacteriaceae if isolated from urine (less than 5%).

Key words: Antibiotic Susceptibility, Enterobacteriaceae, Imipenem, site of isolation