Genotypic characterization of Egypt enterotoxigenic Escherichia coli isolates expressing coli surface antigen 6

• Published in: Journal of infection in developing countries 2013-02, Vol.7 (2), p.90-100
• Main Authors: El-Gendy, Atef M, Mansour, Adel, Shaheen, Hind I, Monteville, Marshall R, Armstrong, Adam W, El-Sayed, Nasr, Young, Sylvia Y N, Klena, John D
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - pharmacology; Antigens; Antigens, Bacterial - analysis; Child, Preschool; Cluster Analysis; E coli; Egypt; Electrophoresis, Gel, Pulsed-Field; Enterotoxigenic Escherichia coli - classification; Enterotoxigenic Escherichia coli - drug effects; Enterotoxigenic Escherichia coli - genetics; Enterotoxigenic Escherichia coli - isolation & purification; Escherichia coli Infections - microbiology; Escherichia coli Proteins - analysis; Genes; Genotype; Humans; Microbial Sensitivity Tests; Molecular Typing; Prospective Studies; Vaccines; Virulence Factors - genetics
• ISSN: 1972-2680; 2036-6590; 1972-2680
• DOI: 10.3855/jidc.2454

One approach to control enterotoxigenic Escherichia coli (ETEC) infections has been to develop vaccines focused on inducing protective immunity against surface expressed antigenic factors. One such factor is coli surface antigen 6 (CS6); ETEC isolates expressing CS6 may also simultaneously co-express surface antigens CS4 or CS5. However, there is little information regarding the inter-relationships of isolates expressing the CS6 antigen alone or in combination with CS4 or CS5. A total of 62 CS6-associated ETEC isolates were evaluated for their antimicrobial susceptibility, mechanisms of resistance, toxin genes, colonization factor expression, and XbaI-pulsed-field gel electrophoretic profiles. We observed 46 XbaI profiles; 31 were exclusive to ETEC expressing CS6 alone and 15 among the ETEC co-expressing CS4 or CS5. Nearly half (47%) of these isolates were resistant to ampicillin, a third (37%) of the isolates were resistant to trimethoprim-sulfamethoxazole, and 24% of the isolates were tetracycline-resistant. A blaTEM gene was detected in 24 (83%) ampicillin-resistant isolates. Trimethoprim-sulfamethoxazole-resistant isolates (n = 23) carried either sulI (n = 1, 4%), sulII (n = 8, 35%) or both genes (n = 10, 43%); 4 had no detectable sul gene. Our results show a lack of clonality among Egypt CS6 E. coli isolates and supports the use and the further research on vaccines targeting this cell surface antigen.