Molecular characterization of Vibrio cholerae responsible for cholera epidemics in Uganda by PCR, MLVA and WGS.

Godfrey Bwire,Atek Kagirita,David A Sack,Joseph B Voeglein,Ambrose Wabwire Buyinza,Amanda Kay Debes,Mathieu Almeida,Christopher Garimoi Orach,O Colin Stine,Shan Li

doi:10.1371/journal.pntd.0006492

Abstract

BackgroundFor almost 50 years sub-Saharan Africa, including Uganda, has experienced several outbreaks due to Vibrio cholerae. Our aim was to determine the genetic relatedness and spread of strains responsible for cholera outbreaks in Uganda.Methodology/Principal findingsSixty-three V. cholerae isolates collected from outbreaks in Uganda between 2014 and 2016 were tested using multiplex polymerase chain reaction (PCR), multi-locus variable number of tandem repeat analysis (MLVA) and whole genome sequencing (WGS). Three closely related MLVA clonal complexes (CC) were identified: CC1, 32% (20/63); CC2, 40% (25/63) and CC3, 28% (18/63). Each CC contained isolates from a different WGS clade. These clades were contained in the third wave of the 7th cholera pandemic strain, two clades were contained in the transmission event (T)10 lineage and other in T13. Analysing the dates and genetic relatedness revealed that V. cholerae genetic lineages spread between districts within Uganda and across national borders.ConclusionThe V. cholerae strains showed local and regional transmission within Uganda and the East African region. To prevent, control and eliminate cholera, these countries should implement strong cross-border collaboration and regional coordination of preventive activities.

Highlights

Vibrio cholerae remains a major cause of morbidity and mortality globally [1]
The goal of this study was to analyze V. cholerae isolates responsible for cholera outbreaks that occurred between 2014–2016 in Uganda using multiplex polymerase chain reaction (PCR), multi-locus variable number of tandem repeat analysis (MLVA) and whole genome sequencing (WGS) to determine the genetic relatedness and spread of V. cholerae isolates from different outbreaks in Uganda
The isolates were from 9 locations: 8 districts in Uganda and a ninth from patients who acquired their illness in Juba, South Sudan, and were treated in Uganda

Summary

Introduction

Vibrio cholerae remains a major cause of morbidity and mortality globally [1]. There have been seven cholera pandemics since the disease was recognized as a global threat [2]. Industrialized countries essentially have eliminated cholera as a public health problem through improved water and sanitation [9]. This enteric bacterium continues to cause deaths and suffering in many countries [10,11,12]. Sub-Saharan Africa bears the highest reported cholera disease burden [13]. The ongoing outbreaks in Africa and elsewhere in the world are part of the seventh pandemic caused by the V. cholerae O1, El Tor lineage [14,15]. For almost 50 years sub-Saharan Africa, including Uganda, has experienced several outbreaks due to Vibrio cholerae.

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Conclusion