Genomic Relatedness of the New Matlab Variants of Vibrio cholerae O1 to the Classical and El Tor Biotypes as Determined by Pulsed-Field Gel Electrophoresis

Abstract

The genomes of the recently described Matlab variants of Vibrio cholerae O1 that are hybrids between classical and El Tor biotypes were compared with those of El Tor and classical biotypes by the use of pulsed-field gel electrophoresis. Dendrograms constructed using the unweighted-pair group method using average linkages generated from NotI restriction patterns of whole-chromosomal DNA grouped these strains into two major clusters that were found to be similar but not identical to those of either of the biotypes. Strains that clustered with the classical biotype appear to have been derived from the classical strains, which are thought to be extinct.

Genetic characteristics of Matlab variants of Vibrio cholerae O1 that are hybrids between classical and El Tor biotypes

“…In this study, all except two strains examined possessed the classical type of ctxB DNA sequence or genotype 1, which is in contrast to the results obtained by PCR from different virulence-associated genetic regions. Notably, the PFGE results from our previous study (Safa et al, 2005) that clustered reference strains (MT-I, MT-II and MT-III) of Matlab variants with the El Tor biotype also disagree with the ctxB typing result.…”

“…Different phenotypic traits (haemolysis of sheep erythrocytes, agglutination of chicken erythrocytes, sensitivity to polymyxin B and to specific phages, and reaction to the Voges-Proskauer test) and genotypic traits (ctxA, acfB, tcpA and rstR) examined in the previous study failed to classify them into classical or El Tor biotypes (Nair et al, 2002). Further characterization of the Matlab type strains by PFGE revealed that type I strains had a classical biotype lineage, whereas types II and III were more closely related to the El Tor biotype (Safa et al, 2005). In this study, we employed extensive PCR-based screening and a DNAsequence-based approach to examine the different virulence genes and/or gene clusters of Matlab variants and other similar strains, and compared the results with those obtained with reference strains of the classical and El Tor biotypes.…”

Outbreaks Caused by New Variants ofVibrio choleraeO1 El Tor, India

“…usually have been recognized as part of the human gingival oral fl ora; some species, including A. rimae and A. parvulum, have been identifi ed as agents of chronic periodontitis (4,5). A. rimae, formerly known as L. rimae (1), forms short, gram-positive, strictly anaerobic, elliptical bacteria with low G+C content (4). A. rimae produces large amounts of lactic acid and has been recovered previously from normal human gingival fl ora (4,5).…”

“…A. rimae, formerly known as L. rimae (1), forms short, gram-positive, strictly anaerobic, elliptical bacteria with low G+C content (4). A. rimae produces large amounts of lactic acid and has been recovered previously from normal human gingival fl ora (4,5). Apart from periodontitis, it has not been implicated in other types of infection.…”

Genetic diversity of El Tor strains of Vibrio cholerae O1 with hybrid traits isolated from Bangladesh and Mozambique

“…None of the strains of classical and El Tor biotype isolated from Bangladesh examined so far by PFGE showed this 398 kb band (Fig. 3) (Islam et al, 2004;Safa et al, 2005). When this 398 kb molecular weight band generated by PFGE was used as template DNA (desired cellular DNA for PCR was extracted from the separated bands in PFGE which were excised from the gel, placed in a dialysis bag, and eluted by electrophoresis using the method described earlier (Maniatis et al, 1989) using primers for the rstR1 gene, it was found that all hybrid strains from different sources amplified the rstR1 gene.…”