ABSTRACT
Aim: This case-control study investigated the various PAI markers, phylogenetic groups and antimicrobial susceptibilityamong DEC and commensal E. coli isolates
Background: Diarrheagenic Escherichia coli [DEC] is an emerging agent among pathogens that cause diarrheal diseases andrepresents a major public health problem in developing countries. The major difference in virulence among DEC pathotypeand commensals may be related to the presence of specific genomic segments, termed pathogenicity islands [PAIs]
Patients and methods: A total of 600 stool specimens from children [450 with and 150 without diarrhea] were collectedand various PAI markers, phylogenetic groups and antimicrobial resistance profile among DEC and commensal E. coliisolates were detected
Results: One hundred sixty eight [90.3%] isolates were resistant to one or more antimicrobial agents. PAI markers weredetected in a substantial percentage of commensal [90%] and DEC isolates [99.3%][P> 0.05]. The most prevalent PAI markeramong DEC and commensal isolates was HPI [91.9% DEC vs. 68% commensal]. We found a high number of PAI markerssuch as SHI-2, Sheand LEE that were significantly associated with DEC. Several different combinations of PAIs were foundamong DEC isolates. Comparison of PAIs among DEC and commensal isolates showed that many DEC isolates [94.8%]carried two or more PAI markers, while 76% of commensals had only one PAI marker [P< 0.05]. According to thephylogenetic classification, group B2 was the most commonly found in the DEC isolates. Furthermore, our results showed thatgroup B2 can be present in commensal isolates [18%]
Conclusion: These results indicate that PAI markers are widespread among commensal and DEC isolates and thesecommensal isolates may be reservoirs for transmission of these markers