Distribution of virulence associated genes in isolated Escherichia coli from avian colibacillosis


1 Department of Microbiology, Faculty of Veterinary Medicine, University of Semnan, Semnan, Iran

2 Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran

3 Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan


BACKGROUND: Colibacillosis is one of the most prevalent
diseases in the world that causes multimillion-dollar annual
losses. OBJECTIVES: In order to evaluate molecular epidemiology
of some virulence associated factors in Escherichia coli,
isolated from poultry, the presence of iut A, iss, hly F, omp T, iro
N, afa, sfa (S)and pap G (II) were investigated by multiplex PCR
assay. METHODS: Two hundred thirty four Escherichia coli
isolated from avian colibacillosis (APEC) and fifty four fecal E.
coli isolates from the feces of apparently healthy birds (AFEC)
were investigated for presence of some virulence associated
genes by two panel of multiplex PCR. Statistical analysis was
performed using |c
2 test. the p-value was |£|0.05. RESULTS:
Among 234 E. coli strains associated with colibacillosis and 54
AFEC strains, 85% of isolates were positive for at least one of the
virulence gene. The three most prevalent genes in E. coli isolated
from colibacillosis were hly F (77.3%), omp T(73%) and iss
(68.2%). Iut A, iro Nand pap G (II) were detected in 157 (67.4%),
152 (65.2%) and 41(17.6%) respectively. None of isolates
harbored sfa (s) and afa genes. Several combination patterns of
virulence genes were detected. Combination of hly F, omp T
(70.8%) was the most prevalent pattern. CONCLUSIONS: the
prevalence of iss, hly F, omp T, iro N genes in APEC isolates was
significantly more than AFEC strains and probably these genes
play an important role in the pathogenesis of APEC strains.