Dataset Information

Antimicrobial resistance genes in enterotoxigenic Escherichia coli O149:K91 isolates obtained over a 23-year period from pigs.

ABSTRACT: A total of 112 Escherichia coli O149:K91 strains isolated from pigs with diarrhea in Quebec, Canada, between 1978 and 2000 were characterized for their genotypic antimicrobial resistance profiles. Tests for resistance to 10 antimicrobial agents were conducted. Resistance to tetracycline and sulfonamides was found to be the most frequent, but resistance to cefotaxime and ceftiofur was absent. An increase in the number of isolates resistant to at least three antimicrobials was observed over time. The distribution of 28 resistance genes covering six antimicrobial families (beta-lactams, aminoglycosides, phenicols, tetracycline, trimethoprim, and sulfonamides) was assessed by colony hybridization. Significant differences in the distributions of tetracycline [tet(A), tet(B), tet(C)], trimethoprim (dhfrI, dhfrV, dhfrXIII), and sulfonamide (sulI, sulII) resistance genes were observed during the study period (1978 to 2000). Sixty percent of the isolates possessed a class 1 integron, illustrating the importance of integrons in the epidemiology of antibiotic resistance in E. coli strains from pigs. Amplification of the integron's variable region resulted in four distinct fragments of 1, 1.3, 1.6, and 1.8 kb, with the 1.6- and 1.8-kb fragments appearing only during the last half of the study period. Examination of linkages among the different resistance genes showed a variety of positive and negative associations. Association analysis of isolates divided into two groups, those isolated between 1978 and 1989 and those isolated between 1990 and 2000, revealed the appearance of new positive resistance gene associations. Our genotypic resistance analyses of ETEC isolates from pigs indicate that many of the antibiotic resistance genes behind phenotypic resistance are not static but, rather, are in a state of flux driven by various selection forces such as the use of specific antimicrobials.

SUBMITTER: Maynard C

PROVIDER: S-EPMC201132 | biostudies-literature | 2003 Oct

REPOSITORIES: biostudies-literature

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Antimicrobial resistance genes in enterotoxigenic Escherichia coli O149:K91 isolates obtained over a 23-year period from pigs.

Maynard Christine C Fairbrother John M JM Bekal Sadjia S Sanschagrin François F Levesque Roger C RC Brousseau Roland R Masson Luke L Larivière Serge S Harel Josée J

Antimicrobial agents and chemotherapy 20031001 10

A total of 112 Escherichia coli O149:K91 strains isolated from pigs with diarrhea in Quebec, Canada, between 1978 and 2000 were characterized for their genotypic antimicrobial resistance profiles. Tests for resistance to 10 antimicrobial agents were conducted. Resistance to tetracycline and sulfonamides was found to be the most frequent, but resistance to cefotaxime and ceftiofur was absent. An increase in the number of isolates resistant to at least three antimicrobials was observed over time. ...[more]

PMID: 14506033

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Project description:This study aimed to characterize in silico enterotoxigenic Escherichia coli F4- and F18-positive isolates (n = 90) causing swine postweaning diarrhea, including pathogenic potential, phylogenetic relationship, antimicrobial and biocide resistance, prophage content, and metal tolerance rates. F4 strains belonged mostly to the O149 and O6 serogroups and ST100 and ST48 sequence types (STs). F18 strains were mainly assigned to the O8 and O147 serogroups and ST10, ST23, and ST42. The highest rates of antimicrobial resistance were found against streptomycin, sulfamethoxazole, tetracycline, trimethoprim, and ampicillin. No resistance was found toward ciprofloxacin, cefotaxime, ceftiofur, and colistin. Genes conferring tolerance to copper (showing the highest diversity), cadmium, silver, and zinc were predicted in all genomes. Enterotoxin genes (ltcA, 100% F4, 62% F18; astA, 100% F4, 38.1% F18; sta, 18.8% F4, 38.1% F18; stb, 100% F4, 76.2% F18) and fimbria-encoding genes typed as F4ac and F18ac were detected in all strains, in addition to up to 16 other virulence genes in individual strains. Phage analysis predicted between 7 and 20 different prophage regions in each strain. A highly diverse variety of plasmids was found; IncFII, IncFIB, and IncFIC were prevalent among F4 isolates, while IncI1 and IncX1 were dominant among F18 strains. Interestingly, F4 isolates from the early 1990s belonged to the same clonal group detected for most of the F4 strains from 2018 to 2019 (ONT:H10-A-ST100-CH27-0). The small number of single-nucleotide polymorphism differences between the oldest and recent F4 ST100 isolates suggests a relatively stable genome. Overall, the isolates analyzed in this study showed remarkably different genetic traits depending on the fimbria type.IMPORTANCE Diarrhea in the postweaning period due to enterotoxigenic E. coli (ETEC) is an economically relevant disease in pig production worldwide. In Denmark, prevention is mainly achieved by zinc oxide administration (to be discontinued by 2022). In addition, a breeding program has been implemented that aims to reduce the prevalence of this illness. Treatment with antimicrobials contributes to the problem of antimicrobial resistance (AMR) development. As a novelty, this study aims to deeply understand the genetic population structure and variation among diarrhea-associated isolates by whole-genome sequencing characterization. ST100-F4ac is the dominant clonal group circulating in Danish herds and showed high similarity to ETEC ST100 isolates from China, the United States, and Spain. High rates of AMR and high diversity of virulence genes were detected. The characterization of diarrhea-related ETEC is important for understanding the disease epidemiology and pathogenesis and for implementation of new strategies aiming to reduce the impact of the disease in pig production.

Project description:In Algeria, the treatment of visceral and cutaneous leishmanioses (VL and CL) has been and continues to be based on antimony-containing drugs. It is suspected that high drug selective pressure might favor the emergence of chemoresistant parasites. Although treatment failure is frequently reported during antimonial therapy of both CL and VL, antimonial resistance has never been thoroughly investigated in Algeria. Determining the level of antimonial susceptibility, amongst Leishmania transmitted in Algeria, is of great importance for the development of public health policies.Within the framework of the knowledge about the epidemiology of VL and CL amassed during the last 30 years, we sampled Leishmania isolates to determine their susceptibility to antimony. We analyzed a total of 106 isolates including 88 isolates collected between 1976 and 2013 in Algeria from humans, dogs, rodents, and phlebotomines and 18 collected from dogs in France. All the Algerian isolates were collected in 14 localities where leishmaniasis is endemic. The 50% inhibitory concentrations (IC50) of potassium antimony tartrate (the trivalent form of antimony, Sb(III)) and sodium stibogluconate (the pentavalent form of antimony, Sb(V)) were determined in promastigotes and intramacrophage amastigotes, respectively. The epidemiological cutoff (ECOFF) that allowed us to differentiate between Leishmania species causing cutaneous or visceral leishmaniases that were susceptible (S+) or insusceptible (S-) to the trivalent form of antimony was determined. The computed IC50 cutoff values were 23.83 ?g/mL and 15.91 ?g/mL for VL and CL, respectively. We report a trend of increasing antimony susceptibility in VL isolates during the 30-year period. In contrast, an increase in the frequency of S- phenotypes in isolates causing CL was observed during the same period. In our study, the emergence of S- phenotypes correlates with the inclusion of L. killicki (syn: L. tropica) isolates that cause cutaneous leishmaniasis and that have emerged in Algeria during the last decade.Our results provide insight into the spatiotemporal dynamics of Leishmania antimony susceptibility in Algeria. We highlight the need for the future implementation of an effective methodology to determine the antimony susceptibility status of Leishmania isolates to detect the emergence of and prevent the dissemination of drug-resistant strains.

Project description:BackgroundEscherichia coli is the leading cause of bloodstream infections, associated with a significant mortality. Recent genomic analyses revealed that few clonal lineages are involved in bloodstream infections and captured the emergence of some of them. However, data on within sequence type (ST) population genetic structure evolution are rare.MethodsWe compared whole genome sequences of 912 E. coli isolates responsible for bloodstream infections from two multicenter clinical trials that were conducted in the Paris area, France, 12 years apart, in teaching hospitals belonging to the same institution ("Assistance Publique-Hôpitaux de Paris"). We analyzed the strains at different levels of granularity, i.e., the phylogroup, the ST complex (STc), and the within STc clone taking into consideration the evolutionary history, the resistance, and virulence gene content as well as the antigenic diversity of the strains.ResultsWe found a mix of stability and changes overtime, depending on the level of comparison. Overall, we observed an increase in antibiotic resistance associated to a restricted number of genetic determinants and in strain plasmidic content, whereas phylogroup distribution and virulence gene content remained constant. Focusing on STcs highlighted the pauci-clonality of the populations, with only 11 STcs responsible for more than 73% of the cases, dominated by five STcs (STc73, STc131, STc95, STc69, STc10). However, some STcs underwent dramatic variations, such as the global pandemic STc131, which replaced the previously predominant STc95. Moreover, within STc131, 95 and 69 genomic diversity analysis revealed a highly dynamic pattern, with reshuffling of the population linked to clonal replacement sometimes coupled with independent acquisitions of virulence factors such as the pap gene cluster bearing a papGII allele located on various pathogenicity islands. Additionally, STc10 exhibited huge antigenic diversity evidenced by numerous O:H serotype/fimH allele combinations, whichever the year of isolation.ConclusionsAltogether, these data suggest that the bloodstream niche is occupied by a wide but specific phylogenetic diversity and that highly specialized extra-intestinal clones undergo frequent turnover at the within ST level. Additional worldwide epidemiological studies overtime are needed in different geographical and ecological contexts to assess how generalizable these data are.

Dataset Information

Antimicrobial resistance genes in enterotoxigenic Escherichia coli O149:K91 isolates obtained over a 23-year period from pigs.

Publications

Antimicrobial resistance genes in enterotoxigenic Escherichia coli O149:K91 isolates obtained over a 23-year period from pigs.

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