Comparison of Four Phenotypic Assays for the Detection of ESBL Producing Gram Negative Bacilli and Assessment of the Magnitude of Carbapenemase-Producing Gramnegative Bacilli Isolated from Specimens Referred to Ethiopian Public Health Institute.
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Date
2020-07
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Addis Abeba University
Abstract
Background: The detection of extended-spectrum β-lactamase producing (ESBL)Enterobacteriaceaeand carbapenemase-producing gram-negative bacilli are of importance for infection control andepidemiological purposes. The common mechanism of resistance to extended spectrum cephalosporinsand carbapenem antibiotics is through the production of ESBL and carbapenemase enzymes. Thus, thisstudy was designed to compare four phenotypic assays to detect ESBLs in clinical isolates ofEnterobacteriaceae and determine the magnitude of carbapenemase-producing gram-negative bacilli.
Objective:To compare four phenotypic assays for the detection of ESBL production and to determine themagnitude of carbapenemase-producing gram-negative bacilli.
Methods:The study was conducted from June 30, 2019, to May 30, 2020. Modified and simplifiedcarbapenem inactivation methods were used to screen for carbapenemase. The MICand combination diskmethods were used to confirm Klebsiella pneumonia carbapenemase (KPC)and Metallo βlactamases(MBL)respectively. ESBL detectionassays (Vitek2 Compact, ESBL Etests, combination disks, DDSmethods on Mueller-Hinton [MHA]) were compared. Initially, data were entered on WHOnet 2019 andanalyzed using both WHOnet 2019 and SPSS 23 version.
Results:Out of 117 clinical isolates, CAZ/CAL disk, CTX/CTL disk, DDS, Vitek 2 compact, MICCAZ/CAL, and MIC CTX/CTL detected, 65% (76/117), 64.1% (75/117),64.1% (75/117), 63.2% (74/117),60.7% (71/117), and 59.8% (70/117)ESBL producers respectively.Out of 429 clinical isolates, 15.4%(66/429), 5.4% (23/429), and 23.77% (102/429 isolates were non-susceptible to carbapenems, carbapenemase positive, and MDR respectively.0.7% (3/429)and 2.3% (10/429)were positivefor KPC and MBLrespectively. The highest and lowest resistance was observed against Ampicillin (92%) and Amikacin(11.2%) respectively.
Conclusions: The prevalence of MDR, carbapenem non susceptible and carbapenemase producing gramnegative bacilli was found to be high in this study. In this study, a combination disk method was found tobe superior to other methods for ESBL detection. Metallo β-lactamase was found to be the most prevalentcarbapenemase among clinical isolates. For prevention infection control and regular surveillance must be enhanced.
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Keywords
Extended-spectrum β-lactamase, Carbapenemase,Modified carbapenem inactivation method,Combination disk method, Ethiopia