Multilocus genetic analysis reveals that the Australian strains of Vibrio cholerae O1 are similar to the pre-seventh pandemic strains of the El Tor biotype.
Episodes of cholera stemming from indigenous Vibrio cholerae strains in Australia are mainly associated with environmental sources. In the present study, 10 V. cholerae O1 strains of Australian origin were characterized. All of the strains were serogroup O1 and their conventional phenotypic traits categorized them as belonging to the El Tor biotype. Genetic screening of 12 genomic regions that are associated with virulence in V. cholerae showed variable results. Analysis of the ctxAB gene showed that the Australian environmental reservoir contains both toxigenic and non-toxigenic V. cholerae strains. DNA sequencing revealed that all of the toxigenic V. cholerae strains examined were of ctxB genotype 2. Whole genome PFGE analysis revealed that the environmental toxigenic V. cholerae O1 strains were more diverse than the non-toxigenic environmental O1 strains, and the absence of genes that make up the Vibrio seventh pandemic island-I and -II in all of the strains indicates their pre-seventh pandemic ancestry.
Safa
Ashrafus
A
Department of Biology and Chemistry, City University of Hong Kong, 83 Kowloon Tong, Kowloon, Hong Kong SAR.
Bhuiyan
Nurul A
NA
International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka 1212, Bangladesh.
Murphy
Denise
D
Public Health Microbiology Laboratory, Forensic and Scientific Services, Cooper, Coopers Plains, Queensland, Australia.
Bates
John
J
Public Health Microbiology Laboratory, Forensic and Scientific Services, Cooper, Coopers Plains, Queensland, Australia.
Nusrin
Suraia
S
International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka 1212, Bangladesh.
Kong
Richard Y C
RYC
Department of Biology and Chemistry, City University of Hong Kong, 83 Kowloon Tong, Kowloon, Hong Kong SAR.
Chongsanguan
Manas
M
Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok 10400, Thailand.
Chaicumpa
Wanpen
W
Molecular Microbiology and Molecular Immunology Laboratories, Faculty of Allied Health, Thammasat University, Pratumatance 12121, Thailand.
Nair
G Balakrish
GB
National Institute of Cholera and Enteric Diseases, Kolkata, India.
D001315:Australia / Q000453:epidemiology; D015373:Bacterial Typing Techniques / Q000379:methods*; D002771:Cholera / Q000453:epidemiology / Q000382:microbiology*; D004196:Disease Outbreaks; D006801:Humans; D008969:Molecular Sequence Data; D014734:Vibrio cholerae / Q000145:classification* / Q000235:genetics*