Culture supernatants from V. cholerae O1 El Tor strains isolated from different geographic areas induce cell vacuolation and cytotoxicity.
OBJECTIVE
To investigate whether the HlyA-induced vacuolating effect is produced by V. cholerae O1 ElTor strains isolated from different geographic origins, including Mexico.


METHODS
Supernatant-induced haemolysis, vacuolating activity and cytotoxicity in Vero cells were recorded. PCR, RFLP analysis and molecular cloning were performed.


RESULTS
All ElTor strains analyzed induced cellular vacuolation. Ribotype 2 strains isolates from the U.S. gulf coast yielded the highest titer of vacuolating activity. Eight of nine strains were haemolytic, while all strains were PCR positive for the hlyA gene. We cloned the hlyA gene from two ElTor strains, a toxigenic (2514-88, ctxAB+) and a non-toxigenic Mexican strain (CM 91-3, ctxAB-). Supernatant from those recombinant E. coli strains induced haemolysis, cell vacuolation and cytotoxicity. RFLP-PCR analysis revealed similarities in the hlyA gene from all strains tested.


CONCLUSIONS
The HlyA-induced vacuolating effect is a widespread phenotype of epidemic V. cholerae O1 ElTor strains.
Vidal
Jorge E
JE
Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, PA, USA.
Enríquez-Rincón
Fernando
F
Giono-Cerezo
Silvia
S
Ribas-Aparicio
Rosa María
RM
Figueroa-Arredondo
Paula
P
D000818:Animals; D001315:Australia / Q000453:epidemiology; D001426:Bacterial Proteins / Q000235:genetics / Q000633:toxicity*; D002522:Chlorocebus aethiops; D002771:Cholera / Q000453:epidemiology / Q000821:virology*; D017077:Culture Media, Conditioned / Q000633:toxicity*; D004269:DNA, Bacterial / Q000235:genetics; D006460:Hemolysin Proteins / Q000235:genetics / Q000633:toxicity*; D006461:Hemolysis; D007843:Latin America / Q000453:epidemiology; D010641:Phenotype; D021521:Ribotyping; D012383:Romania / Q000453:epidemiology; D014481:United States / Q000453:epidemiology; D014617:Vacuoles; D014709:Vero Cells / Q000382:microbiology* / Q000648:ultrastructure; D041241:Vibrio cholerae O1 / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D014774:Virulence / Q000235:genetics
D001426:Bacterial Proteins; D017077:Culture Media, Conditioned; D004269:DNA, Bacterial; D006460:Hemolysin Proteins; C084287:hlyA protein, Vibrio cholerae