Characterization of Escherichia coli Isolates from Commercial Layer Hens with Salpingitis
Mahmood Salehi and Reza Ghanbarpour
DOI : 10.3844/ajavsp.2010.208.214
American Journal of Animal and Veterinary Sciences
Volume 5, Issue 3
Problem statement: Escherichia coli isolates are the most common bacterial agents of salpingitis in commercial layer hens. The objectives of this study were to determine the phylogenetic groups/subgroups and antibiotic resistance of E. coli isolates from salpingitis cases in commercial layer hens farms in southeast of Iran. Approach: One hundred twenty one E. coli isolates from oviducts of layer hens with salpingitis were examined to determine their O-serogroup, phylogenetic group/subgroup and antibiotic resistance pattern. Results: O-serogroup determination test showed that 47 (38.84%) isolates were typeable and belonged to eleven different O serogroups including: O1, O2, O6, O8, O15, O20, O25, O36, O78, O86 and O111 and 71 (58.67%) isolates were O-nontypeable. Three most prevalent serogroup were O78, O2 and O1 respectively. PCR assays showed that the isolates fall into four phylogenetic groups A (41.32%), D (33.88%), B2 (14.87%) and B1 (9.91%). Ninety nine (81.81%) isolates fell into six phylogenetic subgroups including: A0 (17.35%), A1 (23.96%), B22 (5.78%), B23 (9.09%), D1 (13.22%) and D2 (20.66%). All of the E. coli isolates from O78 serogroup belonged to A phylo-group whereas the O2 isolates mostly fell into D group. The maximum antibiotic resistance was against tetracycline (100%) and minimum resistance was against linco-spectin (37.19%). Twenty four isolates (19.83%) were resistant to all of the examined antibiotics. Twenty three different patterns of multiple drug resistance were observed, out of which N-Te-Sxt-Fm- Nfx-C and N-Te-Sxt-Gm-Fm-Nfx-C-Ls was the two most frequent patterns respectively. The resistant isolates were found in all of the phylogenetic groups and or sub groups. Conclusion: There are similarities between salpingitis derived E. coli strains and other avian pathogenic E. coli isolates in phylogroups, O-serogroups and antibio-resistance patterns.
© 2010 Mahmood Salehi and Reza Ghanbarpour. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.