Phylogenetic background and virulence genes of Escherichia coli isolates from colisepticemic and healthy broiler chickens in Iran

Abstract

The purposes of this study were to determine the phylogenetic background and the virulence gene profiles of Escherichia coli isolates from colisepticemic and feces of healthy (AFEC) broiler chickens. In this study, 253 E. coli isolates including 141 avian pathogenic E. coli (APEC) and 112 AFEC isolates were examined by PCR. In general, 253 E. coli isolates distributed among group A (51.8%), B1 (15.8%), B2 (8.7%), and D (23.7%). Ten (8.9%) AFEC isolates segregated in to B1 phylo-group and 102 (91.1%) isolates fell into six different phylogenetic subgroups. Distribution of colisepticemic and fecal isolates differed significantly in their assignments to A and B1 phylo-groups. The three most prevalent virulence genes were crl, fimH, and aer in isolates between both groups. The four genetic markers aer, papC, afa, and sfa were detected significantly more often among colisepticemic isolates than in fecal isolates from healthy broilers. The presence of stx ( 2 ) gene in fecal isolates were significantly differs among the colisepticemic isolates. F17 fimbrial family encoding gene and eae gene were detected in APEC and AFEC isolates, respectively. The colisepticemic and fecal isolates possessed the virulence genes were detected in all of the four phylogenetic groups. Several combination patterns of the virulence genes were detected in APEC and AFEC isolates. In colisepticemic isolates the combination of aer, crl, and fimH genes was the most prevalent pattern. None of the examined isolates harbored the cdt, cnf1, ipaH, and stx ( 1 ) virulence gene sequences.

Prevalence and characteristics of intimin-producing Escherichia coli strains isolated from healthy chickens in Korea

“…Prevalence of aEPEC in birds might vary depending on the geography, health status, and bird species. In the previous studies, there were reports exhibiting the prevalence of aEPEC including 30% of diseased chickens in the United States (Rosario et al, 2004), 15.0% of broilers in Finland, 7.2% of layers in Italy (Dipineto et al, 2006), 2.7% of migratory wild birds in Korea (Oh et al, 2011), 1.8% of chickens in EU (Stordeur et al, 2002), and healthy broilers in Iran (Ghanbarpour et al, 2011), respectively. Similarly, atypical enteropathogenic E. coli strains were isolated from children (9.3%) with diarrhea, compared with the healthy control group (Alikhani et al, 2006).…”

Identification of shiga toxin and intimin coding genes in Escherichia coli isolates from pigeons (Columba livia) in relation to phylotypes and antibiotic resistance patterns

“…There are no scientific reports in the available literature which compare with the results of current study. PCR results revealed that avian fecal E. coli isolates belonged to A (60.7%), B1 (8.9%), B2 (8.9%), and D (21.4%) phylogenetic groups (Ghanbarpour et al 2011). A study on Avian pathogenic E. coli isolates showed that these strains belonged to A (38.0%), D (28.1%), B2 (18.5%), and phylogroup B1 (15.5%) (Rodriguez-Siek et al 2005).…”

Prevalence of Shiga Toxin-Producing and Enteropathogenic Escherichia coli in Wild and Pet Birds in Iran

“…Farooq et al (2009) found 5% and 1% of E. coli strains positive for stx1 and stx2 in pigeons, respectively. In broilers, the stx2 gene was detected in 4.5% of the isolates in Iran (Ghanbarpour et al, 2011). On the other hand, some studies found no Shiga toxin genes in E.coli strains from poultry (Wani et al, 2004;Farooq et al, 2009).…”

“…Moreover, some studies have also investigated STEC strains in wild birds and poultry in different countries (Kobayashi et al, 2002; Morabito et al, 2001;Ghanbarpour et al, 2011). More recently, a new subtype of stx, called stx2f, has been described in STEC in pigeons (Schmidt et al, 2000).…”