Genomic Analysis of Antibiotic-Resistant and -Susceptible Escherichia coli Isolated from Bovine Sources in Maputo, Mozambique.

Abstract

This study reports a genomic analysis of Escherichia coli isolates recovered from 25 bovine fecal composite samples collected from four different production units in Maputo city and around Maputo Province, Mozambique. The genomes were analyzed to determine the presence of antibiotic resistance genes (ARGs), genetic relatedness, and virulence factors known to cause diseases in humans. Whole-genome sequencing was conducted on 28 isolates using an Illumina NextSeq 500 sequencing platform. The genomes were analyzed using BLASTN for the presence of resistance genes and virulence factors, as well as to determine their phylogenetic groups, sequence types (ST), and ST complexes (ST Cplxs). The majority of the isolates (85%) were identified as members of phylogenetic groups B1, with fewer isolates identified as members of group A, and a single isolate identified as group "E/Clade I." The ST analysis demonstrated a higher level of diversity than the phylogenetic group analysis. Sixteen different STs, five ST Cplxs, and seven singleton complexes were identified. A strain identified as a novel ST (ST9215) showed a high level of similarity with an isolate recovered from a wild animal in the Gambia. Seven different ARGs were identified, with tet(B) being the most frequently detected, followed by aph(3″)-Ib, aph(6)-Id, sul2, blaTEM-1B, and dfrA1. Three isolates encoded β-lactam-conferring point mutations in the ampC promoter (-42C>T). In total, 51 different virulence factors were identified among the genomes. This study demonstrates that E. coli from bovine sources in Mozambique encoded multiple antibiotic resistance elements, plasmids, and virulence factors. To the best of our knowledge, this is the first genomic description of antibiotic-resistant E. coli isolated from bovine sources in Mozambique.