Molecular characterization of recent Vibrio cholerae O1, El Tor, Inaba strains isolated from hospitalized patients in Kolkata, India.
OBJECTIVE
To study the phenotypic and genotypic characterization of newly emerged V. cholerae O1, Inaba strains isolated from patients with diarrhoea.


METHODS
Bacterial characterization was made using polymerase chain reaction, ribotyping, PFGE and RFLP.


RESULTS
After its first appearance in July 2004, O1 Inaba became the dominant serotype by March 2005 and totally replaced the former dominant serotype, Ogawa from May 2005. Most of the Inaba isolates belong to a new ribotype RIV. Ogawa and also some Inaba strains isolated during the same period were identified as RIII. Similarly, the majority of the Inaba isolates belong to 'H1' pulsotype and one isolate is type 'H', while the Ogawa isolates were mostly 'H' pulsotype. Presence of CTX prophage was detected in a single site of the chromosome with at least two RS elements.


CONCLUSIONS
There has been a switch of dominant serotype from Ogawa to Inaba in the Kolkata region. This is not necessarily due to emergence of a new clone but does serve as an epidemiological marker. Further analysis at the molecular level will be required to define this trend and to monitor future spread to other regions.
Raychoudhuri
Amit
A
National Institute of Cholera and Enteric Diseases, Kolkata, India.
Chatterjee
Souvik
S
Pazhani
Gururaja P
GP
Nandy
Ranjan K
RK
Bhattacharya
Mihir K
MK
Bhattacharya
Sujit K
SK
Ramamurthy
T
T
Mukhopadhyay
Asish K
AK
D002771:Cholera / Q000453:epidemiology / Q000382:microbiology*; D002772:Cholera Toxin / Q000235:genetics; D002876:Chromosomes, Bacterial / Q000235:genetics; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D006760:Hospitalization; D006801:Humans; D007194:India / Q000453:epidemiology; D017720:Molecular Epidemiology; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D039002:Prophages / Q000235:genetics; D021521:Ribotyping; D041241:Vibrio cholerae O1 / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification
D004269:DNA, Bacterial; D002772:Cholera Toxin