Previous Article | Next Article ![]()
Journal of Clinical Microbiology, 11 1995, 2833-2838, Vol 33, No. 11
SM Faruque, SK Roy, AR Alim, AK Siddique and MJ Albert
Cholera is endemic in Bangladesh, and a regular seasonal pattern of cholera
epidemics occurs. We examined the clonal relationships among 103 clinical
and environmental Vibrio cholerae isolates belonging to O1, O139, or non-O1
non-O139 serogroups isolated during epidemic and interepidemic periods in
Bangladesh and compared them with those of 51 V. cholerae isolates from
four countries in Asia and Africa. These studies were done by a
computer-assisted numerical analysis of the restriction endonuclease
cleavage patterns of rRNA genes (ribotypes). Unweighed pair-group cluster
analysis of BglI- and HindIII-generated band patterns revealed 16 clusters.
Ribotypes were defined as clusters of strains possessing > 98%
similarity. The results showed that 154 isolates could be differentiated
into 15 different ribotypes, and strains belonging to 3 of these ribotypes
(ribotypes I, V, and VIIIA and VIIIB) were isolated more frequently during
the epidemic periods than during interepidemic periods in Bangladesh.
Classical vibrios belonged to six different ribotypes (ribotypes I to VI),
with a mean similarity coefficient of 0.84, and the El Tor vibrios belonged
to five different ribotypes (ribotypes VIIIA and IX to XII), with a mean
similarity coefficient of 0.82. A single clone of El Tor vibrios (ribotype
XII) was resident in Tanzania, whereas Nigeria, Syria, and India shared
toxigenic El Tor strains with Bangladesh. Cholera toxin (CT)-positive O139
vibrios isolated from Bangladesh and India belonged to a single ribotype
(ribotype VIIIB) and were > 98% similar to one of the ribotypes of El
Tor vibrios (ribotype VIIIA), but a CT-negative O139 vibrio from Argentina
(ribotype XIII) was < 75% similar to the same cluster of El Tor vibrios,
thus suggesting more than one possible origin for O139 vibrios. Strains
belonging to the same ribotypes (ribotypes VIII to X) were isolated from
both patients and surface water in Bangladesh, indicating possible
transmission through surface water. A clone of a CT-positive environmental
isolate of non-O1 V. cholerae (ribotype VII) was found to be closely
related (76.3% similarity) to a clone of classical vibrios (ribotype I) and
was only between 27.2 and 56.1% similar to clusters of El Tor, O139, and
two other non-O1 nontoxigenic clones.
Copyright © 1995 by the American Society for Microbiology. All rights reserved.
Molecular epidemiology of toxigenic Vibrio cholerae in Bangladesh studied by numerical analysis of rRNA gene restriction patterns
Molecular Biology Laboratory, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»