Multidisciplinary Digital Publishing Institute (MDPI)
Diseases. 2021 Feb 7;9(1):15. DOI: 10.3390/diseases9010015.
PMID: 33562276
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 1, Binod Dhungel 1, Binod Kumar Yadav 2, Nabaraj Adhikari 1, Upendra Thapa Shrestha 1, Binod Lekhak 1, Megha Raj Banjara 1, Bipin Adhikari 3, Prakash Ghimire 1, Komal Raj Rijal 1*
1 Central Department of
Microbiology, Tribhuvan University, Kirtipur, Kathmandu 44618, Nepal
2 Shahid Gangalal
National Heart Centre, Bansbari, Kathmandu 44618, Nepal
3 Mahidol Oxford
Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol
University, Bangkok 10400, Thailand
* Author to whom correspondence should be addressed.
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.
Keywords: Cefotaximase; ESBL; Nepal; Temoneira (TEM);
antimicrobial resistance; blaCTX-M; blaTEM; uropathogenic E. coli.
