Related Experiment Videos
Characterization of a clinical Vibrio cholerae O139 isolate from Mexico
Salina Parveen1, Samuel R Farrah, Celia Gonzalez-Bonilla
1Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA.
Abstract:
Pathogenic strains of Vibrio cholerae O139 possess the cholera toxin A subunit (ctxA) gene as well as the gene for toxin co-regulated pili (tcpA). We report the isolation of a ctxA-negative, tcpA-negative V. cholerae O139 strain (INDREI) from a patient in Mexico diagnosed with gastrointestinal illness. Certain phenotypic characteristics of this strain were identical to those of V. cholerae O1 biotype El Tor. Unlike ctxA-positive V. cholerae O139 strains, this strain was sensitive to a wide panel of antibiotics, including ampicillin, chloramphenicol, ciprofloxacin, gentamicin, furazolidone, nalidixic acid, nitrofurantoin, tetracycline, trimethoprim-sulfamethoxazole, and streptomycin, but was resistant to polymyxin B. Ribotype and pulsed-field gel electrophoresis profiles of INDRE1 differed from those of ctxA-positive V. cholerae O139 and other V. cholerae strains. Phenotypic characteristics of the Mexico strain were similar to those reported for V. cholerae O139 isolates from Argentina and Sri Lanka.
Insights
A novel Vibrio cholerae O139 strain lacking key virulence genes (ctxA and tcpA) was identified in Mexico. This strain exhibits unique antibiotic sensitivity patterns, differing from typical pathogenic V. cholerae O139.
Area of Science:
- Microbiology
- Infectious Diseases
- Genetics
Background:
- Pathogenic Vibrio cholerae O139 strains are characterized by the presence of cholera toxin A subunit (ctxA) and toxin co-regulated pili (tcpA) genes.
- These virulence factors are crucial for the pathogenesis of cholera.
Purpose of the Study:
- To report the isolation and characterization of a unique Vibrio cholerae O139 strain.
- To investigate the genetic and phenotypic properties of a strain lacking ctxA and tcpA genes.
Main Methods:
- Isolation of Vibrio cholerae O139 strain INDRE1 from a patient in Mexico.
- Phenotypic characterization, including antibiotic susceptibility testing.
- Molecular typing using ribotyping and pulsed-field gel electrophoresis (PFGE).
Main Results:
- Isolation of a ctxA-negative, tcpA-negative V. cholerae O139 strain (INDRE1) from a gastrointestinal illness patient.
- INDRE1 displayed phenotypic characteristics similar to V. cholerae O1 biotype El Tor.
- INDRE1 showed sensitivity to multiple antibiotics but resistance to polymyxin B, differing from ctxA-positive strains.
- Molecular profiles (ribotype, PFGE) of INDRE1 were distinct from other V. cholerae O139 and V. cholerae strains.
- Phenotypic similarities were noted between the Mexico strain and isolates from Argentina and Sri Lanka.
Conclusions:
- The identification of a V. cholerae O139 strain lacking key virulence genes challenges traditional understanding of O139 pathogenicity.
- The distinct antibiotic resistance profile suggests potential differences in epidemiology and treatment strategies.
- Further research is needed to understand the evolutionary and epidemiological significance of such strains.