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Whole genome sequencing reveals high clonal diversity of Escherichia coli isolated from patients in a tertiary care hospital in Moshi, Tanzania.

ABSTRACT: Background:Limited information regarding the clonality of circulating E. coli strains in tertiary care hospitals in low and middle-income countries is available. The purpose of this study was to determine the serotypes, antimicrobial resistance and virulence genes. Further, we carried out a phylogenetic tree reconstruction to determine relatedness of E. coli isolated from patients in a tertiary care hospital in Tanzania. Methods:E. coli isolates from inpatients admitted at Kilimanjaro Christian Medical Centre between August 2013 and August 2015 were fully genome-sequenced at KCMC hospital. Sequence analysis was done for identification of resistance genes, Multi-Locus Sequence Typing, serotyping, and virulence genes. Phylogeny reconstruction using CSI Phylogeny was done to ascertain E. coli relatedness. Stata 13 (College Station, Texas 77,845 USA) was used to determine Cohen's kappa coefficient of agreement between the phenotypically tested and whole genome sequence predicted antimicrobial resistance. Results:Out of 38 E. coli isolates, 21 different sequence types (ST) were observed. Eight (21.1%) isolates belonged to ST131; of which 7 (87.5.%) were serotype O25:H4. Ten (18.4%) isolates belonged to ST10 clonal complex; of these, four (40.0%) were ST617 with serotype O89:H10. Twenty-eight (73.7%) isolates carried genes encoding beta-lactam resistance enzymes. On average, agreement across all drugs tested was 83.9%. Trimethoprim/sulphamethoxazole (co-trimoxazole) showed moderate agreement: 45.8%, kappa =15% and p =?0.08. Amoxicillin-clavulanate showed strongest agreement: 87.5%, kappa?=?74% and p =?0.0001. Twenty-two (57.9%) isolates carried virulence factors for host cells adherence and 25 (65.7%) for factors that promote E. coli immune evasion by increasing survival in serum. The phylogeny analysis showed that ST131 clustering close together whereas ST10 clonal complex had a very clear segregation of the ST617 and a mix of the rest STs. Conclusion:There is a high diversity of E. coli isolated from patients admitted to a tertiary care hospital in Tanzania. This underscores the necessity to routinely screen all bacterial isolates of clinical importance in tertiary health care facilities. WGS use for laboratory-based surveillance can be an effective early warning system for emerging pathogens and resistance mechanisms in LMICs.

SUBMITTER: Sonda T

PROVIDER: S-EPMC5992844 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Whole genome sequencing reveals high clonal diversity of <i>Escherichia coli</i> isolated from patients in a tertiary care hospital in Moshi, Tanzania.

Sonda Tolbert T Kumburu Happiness H van Zwetselaar Marco M Alifrangis Michael M Mmbaga Blandina T BT Aarestrup Frank M FM Kibiki Gibson G Lund Ole O

Antimicrobial resistance and infection control 20180608

<h4>Background</h4>Limited information regarding the clonality of circulating <i>E. coli</i> strains in tertiary care hospitals in low and middle-income countries is available. The purpose of this study was to determine the serotypes, antimicrobial resistance and virulence genes. Further, we carried out a phylogenetic tree reconstruction to determine relatedness of <i>E. coli</i> isolated from patients in a tertiary care hospital in Tanzania.<h4>Methods</h4><i>E. coli</i> isolates from inpatient ...[more]

PMID: 29977533

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Project description:BackgroundEvolutionary analyses of enterohemorrhagic Escherichia coli (EHEC) have identified two distantly related clonal groups: EHEC 1, including serotype O157:H7 and its inferred ancestor O55:H7; and EHEC 2, comprised of several serogroups (O26, O111, O118, etc.). These two clonal groups differ in their virulence and global distribution. Although several fully annotated genomic sequences exist for strains of serotype O157:H7, much less is known about the genomic composition of EHEC 2. In this study, we analyzed a set of 24 clinical EHEC 2 strains representing serotypes O26:H11, O111:H8/H11, O118:H16, O153:H11 and O15:H11 from humans and animals by comparative genomic hybridization (CGH) on an oligoarray based on the O157:H7 Sakai genome.ResultsBackbone genes, defined as genes shared by Sakai and K-12, were highly conserved in EHEC 2. The proportion of Sakai phage genes in EHEC 2 was substantially greater than that of Sakai-specific bacterial (non-phage) genes. This proportion was inverted in O55:H7, reiterating that a subset of Sakai bacterial genes is specific to EHEC 1. Split decomposition analysis of gene content revealed that O111:H8 was more genetically uniform and distinct from other EHEC 2 strains, with respect to the Sakai O157:H7 gene distribution. Serotype O26:H11 was the most heterogeneous EHEC 2 subpopulation, comprised of strains with the highest as well as the lowest levels of Sakai gene content conservation. Of the 979 parsimoniously informative genes, 15% were found to be compatible and their distribution in EHEC 2 clustered O111:H8 and O118:H16 strains by serotype. CGH data suggested divergence of the LEE island from the LEE1 to the LEE4 operon, and also between animal and human isolates irrespective of serotype. No correlation was found between gene contents and geographic locations of EHEC 2 strains.ConclusionThe gene content variation of phage-related genes in EHEC 2 strains supports the hypothesis that extensive modular shuffling of mobile DNA elements has occurred among EHEC strains. These results suggest that EHEC 2 is a multiform pathogenic clonal complex, characterized by substantial intra-serotype genetic variation. The heterogeneous distribution of mobile elements has impacted the diversification of O26:H11 more than other EHEC 2 serotypes.

Dataset Information

Whole genome sequencing reveals high clonal diversity of Escherichia coli isolated from patients in a tertiary care hospital in Moshi, Tanzania.

Publications

Whole genome sequencing reveals high clonal diversity of <i>Escherichia coli</i> isolated from patients in a tertiary care hospital in Moshi, Tanzania.

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