A Molecular and Epidemiological Study of Vibrio Cholerae Isolates from Cholera Outbreaks in Southern Ghana
Date
2020
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
PLOS
Abstract
Cholera remains a major global public health threat and continuous emergence of new Vibrio
cholerae strains is of major concern. We conducted a molecular epidemiological study to
detect virulence markers and antimicrobial resistance patterns of V. cholerae isolates
obtained from the 2012–2015 cholera outbreaks in Ghana. Archived clinical isolates
obtained from the 2012, 2014 and 2015 cholera outbreaks in Ghana were revived by culture
and subjected to microscopy, biochemical identification, serotyping, antibiotic susceptibility
testing, molecular detection of distinct virulence factors and Multi-Locus Variable-Number of
Tandem-Repeat Analysis (MLVA). Of 277 isolates analysed, 168 (60.6%) were confirmed
to be V. cholerae and 109 (39.4%) isolates constituted other bacteria (Escherichia coli,
Aeromonas sobria, Pseudomonas aeruginosa, Enterobacter cloacae and Enterococci faecalis).
Serotyping the V. cholerae isolates identified 151 (89.9%) as Ogawa, 3 (1.8%) as
Inaba and 14 (8.3%) as non-O1/O139 serogroup. The O1 serogroup isolates (154/168,
91.7%) carried the cholera toxin ctxB gene as detected by PCR. Additional virulence genes
detected include zot, tcpA, ace, rtxC, toxR, rtxA, tcpP, hlyA and tagA. The most common
and rare virulence factors detected among the isolates were rtxC (165 isolates) and tcpP
(50 isolates) respectively. All isolates from 2014 and 2015 were multidrug resistant against
the selected antibiotics. MLVA differentiated the isolates into 2 large unique clones A and B,
with each predominating in a particular year. Spatial analysis showed clustering of most isolates
at Ablekuma sub-district. Identification of several virulence genes among the two different
genotypes of V. cholerae isolates and resistance to first- and second-line antibiotics,
calls for scaleup of preventive strategies to reduce transmission, and strengthening of public
health laboratories for rapid antimicrobial susceptibility testing to guide accurate treatment. Our findings support the current WHO licensed cholera vaccines which include both O1
Inaba and Ogawa serotypes
Description
Research Article
Keywords
epidemiological, Cholera, Ghana
Citation
Danso EK, Asare P, Otchere ID, Akyeh LM, Asante-Poku A, Aboagye SY, et al. (2020) A molecular and epidemiological study of Vibrio cholerae isolates from cholera outbreaks in southern Ghana. PLoS ONE 15(7): e0236016. https://doi.org/10.1371/journal.pone.0236016