Detection of drug resistance in Escherichia coli from calves with diarrhea in the Tongliao region: an analysis of multidrug-resistant strains

Zi Wang; Miao Sun; Shuang Guo; Yongqiang Wang; Linghao Meng; Jinchuan Shi; Chao Geng; Dongxu Han; Xiaomeng Fu; Jiangdong Xue; Hongxia Ma; Kai Liu

doi:10.3389/fvets.2024.1466690

Detection of drug resistance in Escherichia coli from calves with diarrhea in the Tongliao region: an analysis of multidrug-resistant strains

Front Vet Sci. 2024 Nov 13:11:1466690. doi: 10.3389/fvets.2024.1466690. eCollection 2024.

Authors

Zi Wang^#^{1

2

3}, Miao Sun^#¹, Shuang Guo⁴, Yongqiang Wang⁵, Linghao Meng¹, Jinchuan Shi¹, Chao Geng¹, Dongxu Han^{1

2

3}, Xiaomeng Fu⁶, Jiangdong Xue^{1

2

3}, Hongxia Ma⁷, Kai Liu^{1

2

3}

Affiliations

¹ College of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao, China.
² Inner Mongolia Engineering Technology Research Center for Prevention and Control of Beef Cattle Diseases, Tongliao, China.
³ Beef Cattle Industry School of Inner Mongolia Autonomous Region, Tongliao, China.
⁴ Hinggan League Animal Disease Control Center, Hinggan League, China.
⁵ Zhalantun Vocational College, Hulunbeier, China.
⁶ Tongliao Vocational College, Tongliao, China.
⁷ College of Animal Science and Technology, Jilin Agricultural University, Changchun, China.

^# Contributed equally.

Abstract

Introduction: Escherichia coli is a major pathogen responsible for calf diarrhea, which has been exacerbated by the irrational and unscientific use of antimicrobial drugs, leading to significant drug resistance.

Methods: This study focused on the isolation and identification of E. coli from calf diarrhea samples in the Tongliao area of China. Isolation was conducted using selective media, Gram staining, and 16S rRNA sequencing. The minimum inhibitory concentration (MIC) of E. coli was determined through the microbroth dilution method. Additionally, the presence of antibiotic-resistant genes was detected, and multidrug-resistant strains were selected for whole-genome sequencing (WGS).

Results: The results revealed that all 40 isolated strains of E. coli exhibited resistance to sulfadiazine sodium, enrofloxacin, and ciprofloxacin, with 90% of the strains being susceptible to polymyxin B. Notably, strains 11, 23, and 24 demonstrated severe resistance. The detection rates of the antibiotic resistance genes TEM-1, TEM-206, strA, strB, qacH, and blaCTX were 100%, indicating a high prevalence of these genes. Moreover, the majority of strains carried antibiotic resistance genes consistent with their resistance phenotypes. WGS of strains 11, 23, and 24 revealed genome sizes of 4,897,185 bp, 4,920,234 bp, and 4,912,320 bp, respectively. These strains carried two, one, and two plasmids, respectively. The prediction of antibiotic resistance genes showed a substantial number of these genes within the genomes, with strain 24 harboring the highest number, totaling 77 subspecies containing 88 antibiotic resistance genes.

Discussion: In conclusion, all 40 isolated strains of E. coli from calf diarrhea in this study were multidrug-resistant, exhibiting a broad distribution of antibiotic resistance genes and mobile components. This poses a significant risk of horizontal gene transfer, highlighting the critical situation of antibiotic resistance in this region.

Keywords: Escherichia coli; antimicrobial resistance genes; calf diarrhea; drug resistance; whole genome sequencing.

Grants and funding

The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This study was supported by the National Natural Science Foundation of China (U23A20242, China), the Inner Mongolia Autonomous Region Colleges and Universities Basic Scientific Research Operating Expenses Program (GXKY22097 and GXKY22082, Inner Mongolia, China), the Inner Mongolia Autonomous Region Natural Science Foundation (2021BS03015, Inner Mongolia, China), the Inner Mongolia Autonomous Region Central Guiding Local Development Fund Project (2022ZY0149, Inner Mongolia, China), the Inner Mongolia Xilin Gol League Science and Technology Project (202213, Inner Mongolia, China).