Genotype Cluster Analysis in PathogenicEscherichia coliIsolates Producing Different CDT Types
Diarrheagenic and uropathogenicE. colitypes are mainly characterized by the expression of distinctive bacterial virulent factors.stx1,stx2(Shiga toxins), andcdt(cytolethal distending toxin) genes have been acquired by horizontal gene transfer. Some virulent genes such asespP(serine protease),etpD(part of secretion pathway), andkatP(catalase-peroxidase), orsfpAgene (Sfp fimbriae), are on plasmids and the others likefliC(flagellin) and thefimHgene (fimbriae type-I) are located on chromosome. Genomic pathogenicity islands (PAIs) carry some virulent genes such ashlygene. To determine the existence of virulence genes incdtclinical isolates, genes includingstx1,stx2,cdt,hly,espP,katP,sfpA,etpD,fliC, andfimHwere assessed by Polymerase Chain Reaction (PCR). The most prevalent isolates foretpDandkatPgenes were 85.7% incdtII.katPgene was also observed 83.3% incdtI. However, in 42.85% ofcdtIIIisolates,espPgene was the most detected. Moreover,hlygene was also the most prominent gene incdtIII(71.42%).sfpA genewas observed in 66.6% ofcdtV.stx1gene was detected in 100% ofcdtII,cdtIV, andcdtVtypes. Presence and pattern of virulence genes were considered amongcdtpositive isotypes and used for their clustering and profiling.