Comparative sequence analysis of recA gene among Vibrio cholerae isolates from Iran with globally reported sequences

ArticleinLetters in Applied Microbiology 53(3):313-23 · June 2011with16 Reads
Impact Factor: 1.66 · DOI: 10.1111/j.1472-765X.2011.03108.x · Source: PubMed
Abstract

To study the genetic relatedness between V. cholerae isolates from Iran and other countries based on housekeeping gene recA sequence analysis. A 995-bp region of the recA gene from 24 V. cholerae isolates obtained from human and surface water origins in Iran over a 5-year period was sequenced and compared with the sequence data from the isolates belonging to other places. Cluster analysis of the constructed dendrogram based on recA sequence divergence for our clinical isolates showed one sequence type (ST), whereas environmental isolates revealed eight STs. Interestingly, one of our environmental isolates was intermixed with clinical isolates in the largest cluster containing the epidemic strains. Our 24 isolates plus 198 global isolates available in the GenBank showed 77 sequence types (STs) with at least one nucleotide difference. Our result suggested that recA sequencing is a reliable analysis method for understanding the relatedness of the local isolates with the isolates obtained elsewhere. Understanding the genetic relatedness between V. cholerae isolates could give insights into the health care system for better control and prevention of the cholera.

    • "Variations which may occur in genetic content of V. cholerae during epidemic and inter-epidemic periods may affect the virulence and genotyping properties of epidemic isolates. Mobile genetic elements including phages, pathogenicity islands, and constins may contribute to genetic variation of V. cholerae [5, 12, 20]. According to performed studies phenotypic characters may not be sufficient to investigate diversity of V. cholerae M. Hajia Á M. Rahbar Department of Molecular Biology, Research Center of Health Reference Laboratories, Ministry of Health and Medical Education, Tehran, Iran M. Rahnamye Farzami Á A. Dolatyar Á M. Imani Á R. Saburian Research Center of Health Reference Laboratories, Ministry of Health and Medical Education, Tehran, Iran H. Masoumi Asl Á M. Mafi Center for Communicable Diseases Control, Ministry of Health and Medical Education, Tehran, Iran B. Bakhshi (&) Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Jalal-Ale-Ahmad Ave, 14117-13116 Tehran, Iran e-mail: b.bakhshi@modares.ac.ir strains because of instability of expressed phenotypes or insufficient discriminatory for strain differentiation [14, 27]. "
    [Show abstract] [Hide abstract] ABSTRACT: A total of 1,187 Vibrio cholerae isolates were received during 2011 cholera outbreaks from 16 provinces in different geographical location to Iranian reference Health laboratory. A random selection was performed, and 61 isolates were subjected to further investigations. Cholera cases were come up from May with nine cases and reached to its maximum rate at August (57 cases) and continued to October after which a fall occurred in September. All of the isolates were susceptible to three antimicrobial agents including ciprofloxacin, cefixime, and ampicillin. The highest rate of resistance was seen to nalidixic acid (96.7 %) and co-trimoxazole (91.8 %). Clonality of isolates was investigated through genotyping by PFGE method. A total of seven pulsotypes were obtained from 61 isolates under study. The pulsotypes were highly related with only 1-3 bands differences. Three pulsotypes (PT5, PT6, and PT7) constituted 93.4 % of total isolates. One environmentally isolated strain showed distinct pattern from clinical specimens. This strain although had no any evidence in identified cholera infections, highlighted selecting more environmental specimens in any future outbreaks as long as human samples. In conclusion, emergence and dominance of Ogawa serotypes after about 7 years in Iran are alarming due to fear of import of new V. cholerae clones from out of the country. Approximately, one third of patients in 2011 cholera outbreak in Iran were of Afghan or Pakistani nationality which makes the hypothesis of import of Ogawa serotype strains from neighboring countries more documented and signifies the need to monitor and protect the boundaries.
    Full-text · Article · Nov 2014 · Current Microbiology
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  • [Show abstract] [Hide abstract] ABSTRACT: The aim of this study was to investigate the presence of TCP gene clusters among clinical and environmental Vibrio cholerae isolates and to explore the genetic relatedness of isolates using ribotyping technique. A total of 50 V. cholerae strains (30 clinical and 20 environmental) were included in this study. Three clinical isolates were negative for TCP cluster genes while the cluster was absent in all of the environmental strains. Ribotyping of rRNA genes with BglI produced 18 different ribotype patterns, three of which belonged to clinical O1 serotype isolates. The remaining 15 ribotypes belonged to clinical non-O1, non-O139 serogroups (two patterns) and environmental non-O1, non-O139 serogroups (13 patterns). Clinical V. cholerae O1 strains from 2004 through 2006 and several environmental non-O1, non-O139 V. cholerae strains from 2006 showed 67.3 % similarity and fell within one single gene cluster. Ribotyping analysis made it possible to further comprehend the close originality of clinical isolates as very little changes have been occurred within rRNA genes of different genotypes of V. cholerae strains through years. In conclusion, ribotyping analysis of environmental V. cholerae isolates showed a substantial genomic diversity supporting the fact that genetic changes within bacterial genome occurs during years in the environment, while only little changes may arise within the genome of clinical isolates.
    No preview · Article · Mar 2013 · Annals of Microbiology
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  • [Show abstract] [Hide abstract] ABSTRACT: Sequence analysis of dnaE, hlyA, and asd housekeeping genes were used to determine the genetic relatedness of our collection of Vibrio cholerae isolated from patients and surface waters over a 5-year period in Iran. The results showed 41, 17, and 9 variable sites throughout the sequenced fragments of dnaE (837 bp), hlyA (495 bp), and asd (295 bp), respectively. The results from sequence typing showed that all our clinical isolates were grouped in the same cluster. Eleven genotypes were identified among the environmental isolates. One environmental isolate was found to be in close genetic relatedness with our clinical isolates. One V. cholerae isolate showed a single-locus variant in the dnaE. For each of the studied genetic loci 10, 7, and 7 sequence types were observed for dnaE, hlyA, and asd, respectively. Only asd sequence analysis could make the distinction between the classical and El Tor isolates which emphasizes on selection of housekeeping locus with better discrimination power for analysis of different groups of isolates. Overall, the results indicated that surface waters in Tehran are a pool of non-toxigenic V. cholerae strains which are rarely related to clinical toxigenic isolates. In addition, our results verified that housekeeping gene sequence analysis could be a suitable approach for determination of the relatedness between clinical and environmental V. cholerae isolates.
    No preview · Article · Feb 2013 · Current Microbiology
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