ObjectiveTo study the virulence genes and the colonization factors (CF) of enterotoxigenic Escherichia coli (ETEC) in Shanghai from 2015 to 2018, describe the feature and provide the evidence for the prevention and control or further research of the ETEC-related diarrhea.
MethodsThe virulence genes (est and elt) and the major CFs (CFA/I, CS1/PCFO71, CS2-8, CS12, CS14, CS17-19, CS21) of 300 ETEC strains were collected and detected in Shanghai from 2015 to 2018 by multiplex real time PCR and the population distribution characteristics described by statistical analysis.
ResultsIn target strains, 57.00% (171/300) carried est alone, and 30.33% (91/300) carried elt alone, while 12.67% (38/300) carried both est and elt.And 68.33% (205/300) of the strains were typed to 18 combinations by 14 groups of CFs detected.Type 13 (CS6 alone, 85/300), type 18 (CS21 alone, 65/300) and type 7 (CS2+CS3+CS21, 17/300) were the top three combinations.By counting the CFs separately in the combinations, the most common CFs were CS21 and CS6.The difference was statistically significant in age distribution among the patients from whom the ETEC carried CS21 or CS6.CS21 and CS6 was frequently found in patients below 40 and above 40 respectively.
ConclusionAmong the ETEC collected in Shanghai from 2015 to 2018, most of the strains carry est gene alone.Though the composition of the virulence genes and the CFs varied in different years, most of the strains carry some major CFs such as CS6 or CS21.The strains carried CS6 alone (mainly with elt) or CS21 alone (all with est) show statistically significant difference in age distribution of the patients.
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