Clonal dissemination of Vibrio parahaemolyticus displaying similar DNA fingerprint but belonging to two different serovars (O3:K6 and O4:K68) in Thailand and India.
Active surveillance of Vibrio parahaemolyticus infection among hospitalized patients in Calcutta, India, showed the appearance of the O4:K68 serovar for the first time in March 1998 alongside the continued predominant incidence of the O3:K6 serovar. Strains belonging to both these serovars have been reported to possess pandemic potential. The genomes of O3:K6 and O4:K68 strains and for comparison, non-O3:K6 and non-O4:K68 strains isolated from two different countries, India and Thailand, were examined by different molecular techniques to determine their relatedness. The O3:K6 and O4:K68 strains from Calcutta and Bangkok carried the tdh gene but not the trh gene. Characterization of representative strains of these two serovars by ribotyping and by arbitrarily primed-polymerase chain reaction (AP-PCR) showed that the isolates had identical ribotype and DNA fingerprint. Pulsed-field gel electrophoresis (PFGE) performed with the same set of strains yielded nearly similar restriction fragment length polymorphism (RFLP) patterns for the O3:K6 and O4:K68 isolates from Calcutta and Thailand. Phylogenetic analysis of the NotI RFLP showed that the O3:K6 and O4:K68 strains formed a cluster with 78-91% similarity thus indicating close genetic relationship between the two different serovars isolated during the same time-frame but from widely separated geographical regions. The non-O3:K6 and non-O4:K68, in contrast, showed different ribotype, AP-PCR and PFGE patterns.
Chowdhury
N R
NR
National Institute of Cholera and Enteric Diseases, Calcutta, India.
Chakraborty
S
S
Eampokalap
B
B
Chaicumpa
W
W
Chongsa-Nguan
M
M
Moolasart
P
P
Mitra
R
R
Ramamurthy
T
T
Bhattacharya
S K
SK
Nishibuchi
M
M
Takeda
Y
Y
Nair
G B
GB
D016172:DNA Fingerprinting; D017931:DNA Primers; D004269:DNA, Bacterial / Q000032:analysis*; D003967:Diarrhea / Q000382:microbiology; D016521:Electrophoresis, Gel, Pulsed-Field; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D013785:Thailand / Q000453:epidemiology; D014735:Vibrio Infections / Q000453:epidemiology / Q000382:microbiology* / Q000635:transmission; D014736:Vibrio parahaemolyticus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification
D017931:DNA Primers; D004269:DNA, Bacterial