Phenotypic Detection of Carbapenem Resistant Enterobacteriaceae Isolates and Assessment of Their Susceptibility to the Novel Ceftazidime-Avibactam Combination

Ibrahim, Dalia M.; Taha, Shereen E.; Abdel Salam, Shimaa A.; Abd El Aziz, Abd El Aziz A.

doi:10.21608/ejmm.2019.282667

Phenotypic Detection of Carbapenem Resistant Enterobacteriaceae Isolates and Assessment of Their Susceptibility to the Novel Ceftazidime-Avibactam Combination

Document Type : New and original researches in the field of Microbiology.

Authors

¹ Department of Medical Microbiology and Immunology, Ain Shams University, Cairo, Egypt

² Department of Anesthesia, Intensive Care and Pain Management, Ain Shams University, Cairo, Egypt

10.21608/ejmm.2019.282667

Abstract

Background: Carbapenems have become one of the last lines of antimicrobials against Gram negative resistant microorganisms. But in last few years, Carbapenem Resistant Enterobacteriaceae (CRE) have been reported all over the world. Numerous phenotypic tests have been planned for detection of carbapenemase activity including the newer modified Carbapenem Inactivation Method (mCIM). There is a strong need for new antibiotics to mitigate the growing threat of antimicrobial resistance (AMR). Objectives: Evaluation of the mCIM as a new method for phenotypic detection of carbapenemase-producing CRE and to test the in vitro susceptibility of the isolates to ceftazidime-avibactam. Methodology: Total of 25 CRE, isolated from 120 clinical specimens then identified by conventional methods over a 6 months period from Intensive Care Units of Surgery Department of Ain Shams University Hospitals. Phenotypic detection of carbapenemase-producing CRE was done by mCIM method compared to meropenem E-test as well as testing the susceptibility of isolates to ceftazidime- avibactam by E test. Results: Twenty-five CRE isolates were detected by meropenem disk diffusion method [Klebsiella pneumoniae (n=19) and E.coli (n=6)]. mCIM was positive for 23 out of 25 isolates (92%) showing 100% sensitivity, 66.6% specificity and 96% accuracy. There is an excellent agreement between meropenem E-test and modified CIM (kappa =0.77; P value >0.001). Twenty-two of CRE isolates (88%) were sensitive to ceftazidime- avibactam. Conclusion: The mCIM method is simple, less subjective, cost effective, sensitive method and plays an important role in detection of CRE. Also, Ceftazidime-avibactam appears to be a promising agent for the treatment of serious CRE infections.

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