Determination of the carbapenem resistance in Escherichia coli isolated from samples obtained from Shahrekordhospitals and determination of their minimum inhibitory concentration

Background and aims: Carbapenems are the final-line treatments for multidrug-resistant, gram-negative infections. The patterns of resistanceto carbapenems among hospital bacterial pathogens vary widely across different hospitals in a country. Considering that Escherichia coli isone of the most important causes of nosocomial infections, it is essential to study its drug resistance.Methods: In this descriptive-analytical study, a total of ۸۰ samples of E. coli isolated from inpatients with urinary tract infections (UTIs)were collected in different wards (i.e., women, urology, infectious, and ICU) of Shahrekord hospitals. After the diagnosis and confirmationof bacteria by standard bacteriological methods, their sensitivity to imipenem and meropenem was investigated by the antibiogram (diskdiffusion)method. Then, the minimum inhibitory concentration (MIC) was determined by the E-test strip according to the Clinical andLaboratory Standards Institute (CLSI) standard.Results: In this study, resistance to meropenem and imipenem by antibiogram (disc diffusion) was observed in ۲۱ (۲۵.۲۶%) and ۲۰ (۲۵%)of the isolates, respectively. Twenty isolates had MIC ≥۴ μg/mL for meropenem, ۱۳ isolates demonstrated MIC≥۴ μg/mL for imipenem, and۱۴ isolates had ۱≤MIC<۴ μg/mL and were semi-sensitive.Conclusion: In general, E. coli had significant resistance to carbapenems. Therefore, rapid and accurate identification of these strains canbe a major step to the treatment and control of these strains and prevention of the spread of the resistance.

Keywords:

Escherichia coli , Carbapenems , Meropenem , Imipenem , Minimum inhibitory concentration