PLoS ONE (Jan 2022)

Genetic relatedness, virulence factors and antibiotics susceptibility pattern of Vibrio cholerae isolates from various regions during cholera outbreak in Tanzania.

  • Hamza Hamad Matimba,
  • Agricola Joachim,
  • Mucho Michael Mizinduko,
  • Irene Anthony Maseke,
  • Salum Kassim Nyanga,
  • Maria Ezekiely Kelly,
  • Ali Said Nyanga,
  • Janneth Maridadi Mghamba,
  • Mtebe Venance Majigo,
  • Ahmed Abade Mohamed

DOI
https://doi.org/10.1371/journal.pone.0265868
Journal volume & issue
Vol. 17, no. 3
p. e0265868

Abstract

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BackgroundCholera continues to cause morbidity and mortality in developing countries, including Tanzania. Since August 2015, Tanzania Mainland has experienced cholera outbreaks affecting 26 regions and a 1.6% case fatality rate. The current study determined the virulence factors, genetic relatedness and antimicrobial susceptibility patterns of the Vibrio cholerae isolated from different regions in Tanzania.MethodsA cross-sectional study that involved the genetic characterization of V. cholerae isolates from eleven regions in Tanzania was carried out. There were 99 V. cholerae isolates collected between January 2016 and December 2017. The study perfomed a Multi-locus Variable-number tandem-repeat analysis for genetic relatedness and Mismatch Amplification Mutation Analysis polymerase chain reaction for analyzing toxin genes. All the isolates were tested for antimicrobial susceptibility using the Kirby Bauer disk diffusion method. Data were generally analyzed using Microsoft excel, where genetic relatedness was analyzed using eBurst software v3.ResultsAll isolates were V. cholerae O1. Ogawa was the most predominant 97(98%) serotype. Isolates were genetically related with a small genetic diversity and were positive for ctxA, tcpA El Tor virulence genes. All isolates (100%) were sensitive to doxycycline, trimethoprim-sulphamethoxazole, tetracycline, ceftriaxone, and chloramphenicol, while 87.8% were sensitive to ciprofloxacin. A high resistance rate (100%) was detected towards erythromycin, nalidixic acid, amoxicillin, and ampicillin.ConclusionThe V.cholerae O1 serotypes Ogawa, El Tor variant predominantly caused cholera outbreaks in Tanzania with strains clonally related regardless of the place and time of the outbreak. Most of the isolates were susceptible to the antibiotic regimen currently used in Tanzania. The high resistance rate detected for the other common antibiotics calls for continuous antimicrobial susceptibility testing during outbreaks.