Unveiling distinct genetic features in multidrug-resistant Escherichia coli isolated from mammary tissue and gut of mastitis induced mice

• Published in: Heliyon 2024-03, Vol.10 (5), p.e26723, Article e26723
• Main Authors: Hoque, M. Nazmul, Faisal, Golam Mahbub, Jerin, Shobnom, Moyna, Zannatara, Islam, Md Aminul, Talukder, Anup Kumar, Alam, Mohammad Shah, Das, Ziban Chandra, Isalm, Tofazzal, Hossain, M. Anwar, Rahman, Abu Nasar Md Aminoor
• Format: Article
• Language: English
• Subjects: Antimicrobial resistance; Complete genomes; E. coli; Mastitis; Mouse; Sequence typing; Virulence
• ISSN: 2405-8440; 2405-8440
• DOI: 10.1016/j.heliyon.2024.e26723

Escherichia coli is one of the major pathogens causing mastitis in lactating mammals. We hypothesized that E. coli from the gut and mammary glands may have similar genomic characteristics in the causation of mastitis. To test this hypothesis, we used whole genome sequencing to analyze two multidrug resistant E. coli strains isolated from mammary tissue (G2M6U) and fecal sample (G6M1F) of experimentally induced mastitis mice. Both strains showed resistance to multiple (>7) antibiotics such as oxacillin, aztreonam, nalidixic acid, streptomycin, gentamicin, cefoxitin, ampicillin, tetracycline, azithromycin and nitrofurantoin. The genome of E. coli G2M6U had 59 antimicrobial resistance genes (ARGs) and 159 virulence factor genes (VFGs), while the E. coli G6M1F genome possessed 77 ARGs and 178 VFGs. Both strains were found to be genetically related to many E. coli strains causing mastitis and enteric diseases originating from different hosts and regions. The G6M1F had several unique ARGs (e.g., QnrS1, sul2, tetA, tetR, emrK, blaTEM-1/105, and aph(6)-Id, aph(3″)-Ib) conferring resistance to certain antibiotics, whereas G2M6U had a unique heat-stable enterotoxin gene (astA) and 7192 single nucleotide polymorphisms. Furthermore, there were 43 and 111 unique genes identified in G2M6U and G6M1F genomes, respectively. These results indicate distinct differences in the genomic characteristics of E. coli strain G2M6U and G6M1F that might have important implications in the pathophysiology of mammalian mastitis, and treatment strategies for mastitis in dairy animals.