Occurrence of fimH gene in Escherichia coli isolates from urinary tract-infected patients (Next Research)

 Occurrence of fimH gene in Escherichia coli isolates from urinary tract-infected patients

Shekhar Kumar Jha^a, Milan Kumar Upreti^a, Sanjit Shrestha^b, Anup Muni Bajracharya^c, Anjali Rawal^d, Upendra Thapa Shrestha^{d *}

^a GoldenGate International College, Department of Microbiology, Battisputali, Kathmandu, Nepal

^b Department of Pathology, Kirtipur Hospital, Kathmandu, Nepal

^c Department of Microbiology, Balkumari College, Narayangarh, Chitwan, Nepal

^d Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal

 

* Corresponding author: Dr. Upendra Thapa Shrestha, Assistant Professor, Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal. Email:  upendra.thapashrestha@cdmi.tu.edu.np / upendrats@gmail.com

 

ABSTRACT

Background: Urinary tract infections (UTIs) remain a major global public health concern, with Escherichia coli accounting for most community-acquired cases. The pathogenicity of uropathogenic E. coli (UPEC) is closely linked to virulence factors such as Type 1 fimbriae, encoded by the fimH gene, which promotes adhesion to uroepithelial cells. This study investigates the prevalence of the fimH gene in E. coli isolates recovered from UTI patients and examines its association with extended-spectrum β-lactamase (ESBL) production and multidrug resistance (MDR).

Methods: A hospital-based cross-sectional study was conducted from January to July 2022 at the Department of Microbiology, Kirtipur Hospital, Kathmandu, Nepal. A total of 1200 mid-stream urine samples were processed during the study period to isolate and identify the bacterial pathogens, including E. coli. The antimicrobial susceptibility patterns of E. coli isolates were performed by using modified Kirby-Bauer disc diffusion testing following CLSI guidelines. Phenotypic confirmation of ESBL production was performed using the Double Disc Synergy Test. Genomic DNA was extracted using the phenol: chloroform method, and the fimH gene was amplified by conventional PCR using specific primers.

Results: Among 1,200 urine samples analyzed, 330 (27.5%) showed significant bacterial growth, with E. coli representing 293 (88.8%) of isolates. Among the first-line antibiotics tested, E. coli showed the highest resistance to amoxicillin and ceftazidime, while the highest resistance was observed to tigecycline among second-line agents. In contrast, resistance to imipenem, cefoperazone-sulbactam, and piperacillin-tazobactam was limited, with no resistance to polymyxin B and colistin. ESBL production was detected in 96 (32.8%) of E. coli strains. ESBL-producing isolates exhibited significantly higher resistance to ceftazidime, levofloxacin, ofloxacin, nitrofurantoin, and imipenem than non-ESBL producers.  57% of the UPEC were MDR strains. PCR analysis revealed that 70.8% of ESBL-producing isolates and 84.4% of MDR strains carried the fimH gene.

Conclusion:  Escherichia coli was the predominant uropathogen, with a high prevalence of ESBL production and multidrug resistance, while nitrofurantoin and amikacin remained the most effective antimicrobial agents. The fimH gene was highly prevalent among UPEC isolates, particularly in ESBL-producing and MDR strains, providing preliminary molecular epidemiological data on circulating UPEC strains in Nepal.

Keywords: Uropathogenic E. coli, ESBL, Multidrug resistant, fimH

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