| dc.description.abstract | In the last three decades, Zambia has experienced frequent cholera outbreaks which
mainly affect fishing camps around the country and peri urban areas in Copperbelt and
Lusaka Provinces where there is unsafe water supply and poor sanitation. In 2009, 2010
and 2016 more than 12000 cases, with about 300 deaths, were reported from Zambia
with Lusaka reporting more cases than the rest of the country. However, the antibiogram
and genetic diversity of the Vibrio cholerae isolates causing these outbreaks in Lusaka
Province were unknown. This knowledge is essential to inform cholera prevention and
control programmes.
This was a laboratory based cross-sectional study that sought to determine the
antibiogram and genetic diversity of Vibrio cholerae isolates from the 2009, 2010 and
2016 cholera outbreaks in Lusaka Province. All available isolates from the respective
outbreaks were included in this study and they were characterised by serotyping,
antimicrobial susceptibility testing and macro-restriction analysis using Pulsed-Field Gel
Electrophoresis. The 2009 and 2016 outbreaks yielded only the Ogawa serotype, while
the 2010 outbreak only yielded the Inaba serotype. All the isolates were 100% resistant
to nalidixic acid and nitrofurantoin. The 2009 and 2010 cholera outbreak isolates
showed 100% multidrug resistance while 67 % of 2016 were multidrug resistant. Macrorestriction
analysis demonstrated high diversity among the isolates with six clusters of at
least 92% similarity. The largest cluster comprised 12 isolates with 97.8-100%
similarity, while the smallest cluster comprised 3 isolates with 95.3-98% similarity.
This study demonstrated that both the Inaba and Ogawa serotypes were responsible for
the cholera outbreaks with only one of the serotypes responsible for each particular
v
outbreak; 2009(Ogawa), 2010(Inaba) and 2016(Ogawa). The study also revealed
multidrug resistant Vibrio cholerae strains circulating in all the three outbreaks. Macrorestriction
analysis demonstrated high genetic diversity among the Vibrio cholerae
isolates, suggesting that the isolates were not from the same source of infection. The
findings in this study will be used to guide therapy and track the sources and spread of
infection for effective cholera management. There is need to establish a national
surveillance system for cholera to monitor antibiotic resistance and to track the virulence
and antibiotic resistance genes of Vibrio cholerae strains circulating in Zambia to gain
insight into their clinical implications. | en |
