Duong Truong Thi Quoy

Equine piroplasmosis, which is caused by Theileria equi and Babesia caballi , has a significant impact on the veterinary and economic aspects of the global horse industry. However, many countries, including Vietnam, have not yet conducted epidemiological surveys to determine the prevalence of these haemoparasites. The aim of this study was therefore to detect T. equi and/or B. caballi infections in horses and to identify their genotypes. Blood samples were collected from 154 seemingly healthy horses in 8 districts of Hanoi, Thai Nguyen, and Son La provinces located in the northern part of the country. Twenty-four horses (15.58%, 95% CI: 10.70–22.14%) were infected with T. equi in six districts. Babesia caballi was not detected. No significant association was found between gender, host age, and the number of infected horses. Phylogenetic analysis of the 18S rRNA sequences from the positive DNA samples revealed genotypes A, C, and E.The results of this study confirm the presence of equine theileriosis in northern Vietnam and highlight the need for nationwide studies of equine piroplasmosis involving a large sample size.

We analyzed and compared genomes of Extended Spectrum Beta-Lactamase (ESBL)-producing Escherichia coli from pigs and pig farm workers at 116 farms in Vietnam. Analyses revealed the presence of bla_CTX-M-55, bla_CTX-M-27, bla_CTX-M-15, bla_CTX-M-14, bla_CTX-M-3, bla_CTX-M-65, bla_CTX-M-24, bla_DHA-1, and bla_CMY2 in both hosts. Most strains from pigs contained quinolones (qnr) and colistin resistance genes (mcr-1 and mcr-3). Isolates predominantly harbored more than one plasmid replicon and some harbored plasmid replicons on the same contigs as the ESBL genes. Five strains from farm workers of ST38 (2), ST69 (1), and ST1722 (2) were classified as either uropathogenic E. coli (UPEC_HM)/extraintestinal pathogenic E. coli (ExPEC_JJ) or UPEC_HM, and the remaining were genetically distinct commensals. A high heterogeneity was found among the ESBL-producing E. coli from pigs and workers, with most isolates belonging to unrelated phylogroups, serogroups, and sequence types with >4046 Single-Nucleotide Polymorphisms-(SNPs). In comparing the genomes of pig isolates to those from humans, it appeared that ESBL-producing E. coli in workers did not predominantly originate from pigs but were rather host-specific. Nevertheless, the occurrence of ESBL-producing E. coli carrying plasmid-mediated colistin and quinolone resistance genes in pigs could represent a potential source for horizontal transmission to humans through food rather than direct contact.

Animals are considered important sources of ESBL/AmpC-producing bacteria in humans. We analyzed indications of transfer of ESBL/AmpC genes between pigs and pig farmers in Vietnam by analyzing whole genome sequences of 114 ESBL/AmpC-producing E. coli isolated from the two hosts, and performed conjugation experiments and plasmid profiling to confirm that such transfer could have happened. ESBL-encoding genes detected in pigs and pig farmers included bla_CTX–M-55, bla_CTX-M-27, bla_CTX-M-65, bla_CTX-M-15, bla_CTX-M-14, bla_CTX-M-3, bla_CTX-M-24, and bla_CARB-2, and AmpC β-lactamases included bla_CMY-2, bla_DHA-1, and bla_CMY-42. The most frequent ESBL gene, bla_CTX-M-55, was carried on plasmid with replicons types IncF, IncX, IncH, IncN, IncR, and IncP. The insertion transposases downstream of the bla_CTX-M-55 gene were different in plasmids carried by different strains. The second most detected gene, bla_CTX-M-27, is found in a stable genetic arrangement with the same flanking transposons seen across strains, and the gene was located on similar conjugal IncF plasmid types, suggesting a horizontal spread of these plasmids. In three strains, we observed a novel bla_CTX-M-27 harboring IncF type of plasmid which had not been reported before. Its closest reference in NCBI was the non-ESBL Salmonella Typhimurium plasmid pB71 that might have experienced an insertion of bla_CTX-M-27. Our data also point to an emergence of plasmids co-carrying ESBL genes, mcr genes, quinolones and other antimicrobials resistance determinants, and such plasmids require special attention. Plasmids phylogeny confirmed that the bla_CTX-M-55 encoding plasmids varied considerably, while those encoding bla_CTX-M-27 were closely related. Plasmids harboring both ESBL genes were confirmed to be conjugative and not to differ in transfer efficacy. The isolates carrying the plasmids, even those with plasmids of similar types, showed wide genetic variation with high number of SNPs, suggesting horizontal spread of plasmids into different clonal lines. Their virulence profiles did not confirm to known pathotypes, suggesting that unrelated commensals are a main reservoir for ESBL and AmpC β-lactamases in both humans and pigs. Overall, despite evidence of transferability of plasmids in the analyzed strains, our findings do not support that ESBL-producing E. coli from pigs or their ESBL/AmpC encoding plasmids are commonly spread to workers in close contact with the animals.