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

 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 (bla_TEM and bla_CTX-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 bla_TEM and bla_CTX-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 bla_CTX-M gene and 41.6% (5/12) tested positive for the bla_TEM 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.

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