Detection of TEM and CTX-M Genes in Escherichia coli Isolated from Clinical Specimens at Tertiary Care Heart Hospital, Kathmandu, Nepal.

Ram Shankar Prasad Sah,Upendra Thapa Shrestha,Megha Raj Banjara,Nabaraj Adhikari,Binod Kumar Yadav,Komal Raj Rijal,Bipin Adhikari,Binod Dhungel,Prakash Ghimire,Binod Lekhak

doi:10.3390/diseases9010015

Abstract

Background: Antimicrobial resistance (AMR) among Gram-negative pathogens, predominantly ESBL-producing clinical isolates, are increasing worldwide. The main aim of this study was to determine the prevalence of ESBL-producing clinical isolates, their antibiogram, and the frequency of ESBL genes (blaTEM and blaCTX-M) in the clinical samples from patients. Methods: A total of 1065 clinical specimens from patients suspected of heart infections were collected between February and August 2019. Bacterial isolates were identified on colony morphology and biochemical properties. Thus, obtained clinical isolates were screened for antimicrobial susceptibility testing (AST) using modified Kirby–Bauer disk diffusion method, while ESBL producers were identified by using a combination disk diffusion method. ESBL positive isolates were further assessed using conventional polymerase chain reaction (PCR) to detect the ESBL genes blaTEM and blaCTX-M. Results: Out of 1065 clinical specimens, 17.8% (190/1065) showed bacterial growth. Among 190 bacterial isolates, 57.4% (109/190) were Gram-negative bacteria. Among 109 Gram-negative bacteria, 40.3% (44/109) were E. coli, and 30.2% (33/109) were K. pneumoniae. In AST, 57.7% (n = 63) Gram-negative bacterial isolates were resistant to ampicillin and 47.7% (n = 52) were resistant to nalidixic acid. Over half of the isolates (51.3%; 56/109) were multidrug resistant (MDR). Of 44 E. coli, 27.3% (12/44) were ESBL producers. Among ESBL producer E. coli isolates, 58.4% (7/12) tested positive for the blaCTX-M gene and 41.6% (5/12) tested positive for the blaTEM gene. Conclusion: Half of the Gram-negative bacteria in our study were MDR. Routine identification of an infectious agent followed by AST is critical to optimize the treatment and prevent antimicrobial resistance.

Highlights

Escherichia coli and Klebsiella species comprise the largest portion of the Gram-negative pathogens in several nosocomial and community-acquired infections, such as intra-abdominal infection, bloodstream infection (BSI), meningitis, and pyogenic liver abscess (PLA) [1]
All pathogenic strains of Gram-negative bacteria are responsible for several infections, including gastroenteritis, urinary tract infection (UTI), septicemia, nosocomial infections, pneumonia, brain and abdominal abscess, and neonatal meningitis [3]
Antimicrobial resistance (AMR) is the condition in which pathogenic strains of the bacteria develop resistance against the specific drug prescribed in response to that microorganism(s) [6,7]

Summary

Introduction

All pathogenic strains of Gram-negative bacteria are responsible for several infections, including gastroenteritis, urinary tract infection (UTI), septicemia, nosocomial infections, pneumonia, brain and abdominal abscess, and neonatal meningitis [3]. Fluroquinolones, cephalosporins, β-lactams, and β-lactamases inhibitors alone or in combination are the frequently prescribed drugs in response to infections caused by Gram-negative bacteria [4]. Overuse of such drugs in humans, animals, and the environment is deemed responsible for the emergence of antibiotic resistance [5]. Antimicrobial resistance (AMR) is the condition in which pathogenic strains of the bacteria develop resistance against the specific drug prescribed in response to that microorganism(s) [6,7]

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