Comparative Characterization of Vibrio cholerae O1 from Five Sub-Saharan African Countries Using Various Phenotypic and Genotypic Techniques.

Anthony M Smith,Delphine Sauvageot,Husna Ismail,Arvinda Sooka,Karen H Keddy,Bradford D Gessner,Bawimodom Bidjada,Diallo M Saliou,Berthe-Marie Njanpop-Lafourcade,Nomsa Tau,José P Langa,Berthe N Miwanda,Martin A Mengel,Adèle Kacou N’Douba,Lorenz Von Seidlein

doi:10.1371/journal.pone.0142989

Abstract

We used standardized methodologies to characterize Vibrio cholerae O1 isolates from Guinea, Democratic Republic of the Congo (DRC), Togo, Côte d’Ivoire and Mozambique. We investigated 257 human isolates collected in 2010 to 2013. DRC isolates serotyped O1 Inaba, while isolates from other countries serotyped O1 Ogawa. All isolates were biotype El Tor and positive for cholera toxin. All isolates showed multidrug resistance but lacked ciprofloxacin resistance. Antimicrobial susceptibility profiles of isolates varied between countries. In particular, the susceptibility profile of isolates from Mozambique (East-Africa) included resistance to ceftriaxone and was distinctly different to the susceptibility profiles of isolates from countries located in West- and Central-Africa. Molecular subtyping of isolates using pulsed-field gel electrophoresis (PFGE) analysis showed a complex relationship among isolates. Some PFGE patterns were unique to particular countries and clustered by country; while other PFGE patterns were shared by isolates from multiple countries, indicating that the same genetic lineage is present in multiple countries. Our data add to a better understanding of cholera epidemiology in Africa.

Highlights

Cholera is well-established in Africa, with numerous outbreaks reported and tens of thousands of deaths estimated to occur annually [1]
Conventional PCR and analysis of PCR products using agarose gel electrophoresis was used to detect the presence of allelic variants of the toxin co-regulated pilus which determined the biotype of V. cholerae O1 isolates [35]
pulsed-field gel electrophoresis (PFGE) patterns were analyzed using BioNumerics Software (Applied Maths, Sint-Martens-Latem, Belgium) with dendrograms of the patterns created using the unweighted pair group method with arithmetic averages (UPGMA), with analysis of banding patterns incorporating the Dice-coefficient at an optimization setting of 1.5% and a position tolerance setting of 1.5%

Summary

Introduction

Cholera is well-established in Africa, with numerous outbreaks reported and tens of thousands of deaths estimated to occur annually [1]. We employed standardized methodologies to phenotypically and genotypically characterize, compare and investigate V. cholerae O1 isolates from Guinea, DRC, Togo, Côte d’Ivoire and Mozambique collected in 2010 to 2013, to provide a basis for understanding disease spread and the relatedness of circulating V. cholerae O1 isolates in sub-Saharan Africa. This information may highlight the emergence of new predominant multidrug-resistant or virulent clones, as well as provide baseline data for future comparisons, should new cholera cases emerge in Africa or on other continents

Materials and Methods

Ethical approval

Results

Discussion