Phenotypic and genetic characterization of vibrio cholera o1 isolated from various regions of Kenya between 2007 and 2010

Abstract

IntroductionCholera, a disease caused by Vibrio cholerae O1 and O139 remains an important public health problem globally. In the last decade, Kenya has experienced a steady increase of cholera cases. In 2009 alone, 11,769 cases were reported to the Ministry of Public Health and Sanitation. This study sought to describe the phenotypic characteristics of the isolated V. cholerae isolates.MethodsThis was a laboratory based cross-sectional study that involved isolates from different cholera outbreaks. Seventy six Vibrio cholerae O1 strains from different geographical areas were used to represent 2007 to 2010 cholera epidemics in Kenya, and were characterized by serotyping, biotyping, polymerase chain r(PCR), pulsed-field gel electrophoresis (PFGE) and ribotyping along with antimicrobial susceptibility testing.ResultsSeventy six Vibrio cholerae O1 strains from different geographical areas were used to represent 2007 to 2010 cholera epidemics in Kenya. Serotype Inaba was dominant (88.2%) compared to Ogawa. The isolates showed varying levels of antibiotic resistance ranging from 100% susceptible to tetracycline, doxycycline, ofloxacin, azithromycin, norfloxacin and ceftriaxone to 100% resistant to furazolidone, trimethoprim-sulfamethoxazole, polymyxin-B and streptomycin. The isolates were positive for ctxA, tcpA (El Tor), rtxC genes and were biotype El Tor variant harboring classical ctxB gene. All the isolates were classified as cholera toxin (CT) genotype 1 as they had mutation in the ctxB at positions 39 and 68. All the isolates had genetically similar NotI PFGE and BglI ribotype patterns. The absence of any observed variation is consistent with a clonal origin for all of the isolates.ConclusionKenya experienced cholera numerous outbreak from 2007-2010. The clinical Vibrio cholerae O1 isolates from the recent cholera epidemic were serotypes Inaba and Ogawa, Inaba being the predominant serotype. The Vibrio cholerae O1 strains were biotype El Tor variants that produce cholera toxin B (ctx B) of the classical type and were positive for ctxA, tcpA El Tor and rtxC genes.

Epidemiology and Antibiogram Profile of <i>Vibrio cholerae</i> Isolates between 2004–2013 from Odisha, India

“…Several other workers also reported 100% resistance to co-trimoxazole from North Karnataka (19) and Cameroon (18). (12,(16)(17)(18). During the study the El Tor variants of V.cholerae were reported from 2007 onwards causing cholera outbreaks and epidemics in different parts of the state and also spread to different areas of Odisha (7,30).…”

Fluoroquinolone-Resistant Enteric Bacteria in Sub-Saharan Africa: Clones, Implications and Research Needs

“…It is highly likely that these strains are the same clone and that the same QRDR mutations are responsible for fluoroquinolone resistance. High levels of resistance to nalidixic acid or reduced susceptibility to ciprofloxacin in likely similar V. cholerae O1 clones causing epidemics in DRC and Kenya have also been shown (Mercy et al, 2014 ; Miwanda et al, 2015 ; Table 1 ), but a lack of standard methodology for clonal analysis prevents an understanding of clonal spread across Africa. Although ciprofloxacin has only a reduced susceptibility in these strains and continues to be used for cholera management, if additional mutations occur in these circulating clones, resistance to ciprofloxacin may develop.…”

Characterization of Vibrio cholerae O1 isolates responsible for cholera outbreaks in Kenya between 1975 and 2017

“…Our results of the sheep erythrocyte hemolysis test were consistent with those reported elsewhere, in which the test has been reported to be of limited use since the El Tor strains lost their hemolytic activity in the late 1960s yielding variable results. 19 Previous cholera studies in Kenya in 1983 32 and 2007-2010 18 reported the V. cholerae O1 strains as being polymyxin B resistant. The results from this study demonstrate that polymyxin B sensitive strains emerged in Kenya in the mid-2000s and completely replaced polymyxin B resistant strains by the year 2016.…”

“…Another study reported that strains isolated between 2007 and 2010 were biotype El Tor variants possessing the cholera toxin B subunit gene (ctxB) and were positive for the ctxA, tcpA of El Tor biotype and rtxC genes. 18 However, their evolutionary lineage and how they compare with other strains previously isolated from other countries where cholera is endemic has not been described. The present study aimed to describe the evolving phenotypic and genotypic traits of V. cholerae O1 strains that were collected over the past four decades in Kenya and other Asian countries where cholera outbreaks are prevalent.…”