Browsing by Author "Dintwe, Galaletsang"

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    Characterization of Escherichia coli isolated from poultry in the Chobe region of Botswana by molecular methods
    Yi, Saehah; Bywater, Auja; Dintwe, Galaletsang; Haidl, Thomas; Cameron, Andrew; Ponder, Monica A.; Alexander, Kathleen A. (2024-07-15)
    Introduction: Diarrheal illness incidence is high in rural dryland environments, including the Chobe region of Botswana, where peaks are often associated with high rainfall events. Antibiotic resistance (ABR) is also a growing problem in the region. Contributions of poultry to diarrheal illness and ABR in the region are not well understood. Purpose: Characterize the virulence potential and ABR of E.coli isolated from chicken purchased from local vendors in Botswana using molecular techniques, including whole genome sequencing. Methods: Poultry was purchased in Kasane, Botswana and enriched within 24h. E.coli was isolated using MacConkey and EMB agar. Isolates were shipped to Virginia Tech for molecular and antibiotic resistance characterization. Multiplex PCR was used to detect presence of genes phoA (all E.coli), and diarrheagenic E.coli (eae, and est1b). Phenotypic ABR was determined using CLSI disk diffusion methods. Whole genome sequencing was performed using an Illumina MiSeq system and genome annotated using BV-BRC. Results: E.coli was isolated from 62% (38/61) of poultry samples. Five isolates were classified as diarrheagenic based on eae, none were positive for est1LB. Multidrug resistance (3+) was seen in 26 isolates and resistance to 1 or more antibiotics in 41 E.coli isolates. Resistance amongst chicken isolates was as follows: tetracycline (29), doxycycline (21), sulfamethoxazole (20), streptomycin (15), ampicillin (15), chloramphenicol (9), ciprofloxacin (6), gentamicin (4), c ceftriaxone (4), amoxicillin-clavulanic acid (3) and azithromycin (1). Comprehensive analysis of the genomes from chicken intestinal isolates revealed large numbers of virulence genes (125-252) common amongst diarrheagenic E.coli. Antibiotic resistance genes (65-85) were also present including those encoding resistance to ampicillin, ceftriaxone, doxycycline, streptomycin, and tetracycline. Significance: While prevalence of diarrheagenic E.coli was low, antibiotic resistant E.coli were frequently isolated. E.coli may be an important sentinel species to evaluate ABR emergence and effectiveness of control strategies by Botswana poultry producers.
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    Characterization of Diarrheagenic Escherichia coli and Salmonella enterica from Produce in the Chobe District of Botswana
    Bywater, Auja; Dintwe, Galaletsang; Alexander, Kathleen A.; Ponder, Monica A. (Elsevier, 2024-08-24)
    Diarrheal disease is a leading cause of death in children in low- and moderate-income countries. Fresh produce, including fruits and vegetables, may harbor diarrheal disease-causing bacteria including strains of Salmonella enterica and Escherichia coli. This study aimed to determine the prevalence and antibiotic resistance profiles of S. enterica and E. coli isolated from produce samples (n = 207) obtained from retail markets in northern Botswana in Chobe District of Botswana in 2022. Samples were enriched in the appropriate selective media: Brilliant Green Bile Broth for E. coli and Rappaport Vassiliadis Broth for S. enterica. E. coli were confirmed by PCR detecting the phoA gene, and classified as potentially pathogenic through screening for the eae, stx, and stx2 and estIb genes. S. enterica isolates were confirmed using invA primers. Isolates were evaluated for resistance to ampicillin, amoxicillin-clavulanic acid, chloramphenicol, cefotaxime, doxycycline, streptomycin, sulfamethoxazole, and tetracycline antibiotic using the Kirby-Bauer Disk Diffusion method. E. coli was isolated from 15.5% of produce samples (n = 207). The gene eae was detected from 1.5% of samples, while stx1, stx2, and estIb were not detected. Resistance to one or more antibiotics was common (72%) with the majority of the resistant E. coli (n = 32) isolated from fruits (22%) and greens (18%) compared to other types of vegetables. Multidrug resistance (MDR, resistant to 3 or more antibiotics) was identified in 18% of samples. S. enterica was isolated from 3.4% of produce samples (7, n = 207). Resistance was uncommon among the S. enterica isolates (1/7). Overall prevalence of diarrheagenic S. enterica and E. coli was low; however, their presence and that of MDR E. coli in foods commonly consumed raw increases the risk to vulnerable populations. Strategies to reduce contamination of fresh produce and public education on washing and cooking some types of produce may be useful to reduce disease.