Genotypic Characterization of Egypt Enterotoxigenic Escherichia coli Isolates Expressing Coli Surface Antigen 6
NATIONAL NAVAL MEDICAL CENTER BETHESDA MD
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Introduction 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. Methodology 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. Results We observed 46 XbaI profiles 31 were exclusive to ETEC expressing CS6 alone and 15 among the ETEC coexpressing 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, suIII n 8, 35 or both genes n 10, 43 4 had no detectable sul gene. Conclusion 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.
- Medicine and Medical Research