Genetic diversity and virulence profiles of Escherichia coli causing salpingitis and peritonitis in broiler breeders

TY - JOUR

T1 - Genetic diversity and virulence profiles of Escherichia coli causing salpingitis and peritonitis in broiler breeders

AU - Pires dos Santos, Teresa M S

AU - Bisgaard, Magne

AU - Christensen, Henrik

PY - 2013/3/23

Y1 - 2013/3/23

N2 - The genetic relatedness and virulence profiles of avian pathogenic Escherichia coli that caused salpingitis and peritonitis in 68 broiler breeders from 21 Danish farms were determined by multilocus sequence typing (MLST), pulsed-field-gel-electrophoresis (PFGE), ECOR phylogrouping, and PCR-based virulotyping. Phylogroups A, B1, B2, and D accounted for 19.1%, 5.9%, 52.9%, and 22.1% of the isolates, respectively. Overall, a total of five main MLST-based clonal groups (3-38 isolates) were identified, comprising 85.3% of the isolates. The most common sequence type (ST) was ST95 (n=12), followed by the ST428-, ST23- and ST350-clonal complexes (CCs) (n=8, n=7 and n=6, respectively). The emerging, antimicrobial resistance-associated clones, ST131 and ST648, were represented by five and three isolates, respectively, whereas ST352 and the ST168 CC comprised four isolates each. Phylogroup-B2 isolates showed a greater prevalence of nine virulence genes (P<0.05). One specific clonal group was significantly associated with phylogroup-B2 isolates (P<0.001), and with isolates that induced secondary septicemia (P=0.001). PFGE analysis revealed 12 clusters of genetically related strains (2-12) sampled from unrelated and geographically distant farms, indicating the widespread distribution and recent vertical transmission of particular APEC lineages. Certain lineages showed more diversity, substantiating that long-term, endemic transmission has been maintained. In conclusion, endemic lineages of E. coli that cause salpingitis and peritonitis in broiler breeders, although diverse, tend to be phylogenetically related, and demonstrate conserved virulence genotypes that might be associated with greater pathogenic potential.

AB - The genetic relatedness and virulence profiles of avian pathogenic Escherichia coli that caused salpingitis and peritonitis in 68 broiler breeders from 21 Danish farms were determined by multilocus sequence typing (MLST), pulsed-field-gel-electrophoresis (PFGE), ECOR phylogrouping, and PCR-based virulotyping. Phylogroups A, B1, B2, and D accounted for 19.1%, 5.9%, 52.9%, and 22.1% of the isolates, respectively. Overall, a total of five main MLST-based clonal groups (3-38 isolates) were identified, comprising 85.3% of the isolates. The most common sequence type (ST) was ST95 (n=12), followed by the ST428-, ST23- and ST350-clonal complexes (CCs) (n=8, n=7 and n=6, respectively). The emerging, antimicrobial resistance-associated clones, ST131 and ST648, were represented by five and three isolates, respectively, whereas ST352 and the ST168 CC comprised four isolates each. Phylogroup-B2 isolates showed a greater prevalence of nine virulence genes (P<0.05). One specific clonal group was significantly associated with phylogroup-B2 isolates (P<0.001), and with isolates that induced secondary septicemia (P=0.001). PFGE analysis revealed 12 clusters of genetically related strains (2-12) sampled from unrelated and geographically distant farms, indicating the widespread distribution and recent vertical transmission of particular APEC lineages. Certain lineages showed more diversity, substantiating that long-term, endemic transmission has been maintained. In conclusion, endemic lineages of E. coli that cause salpingitis and peritonitis in broiler breeders, although diverse, tend to be phylogenetically related, and demonstrate conserved virulence genotypes that might be associated with greater pathogenic potential.

KW - Faculty of Health and Medical Sciences

KW - Escherichia coli

KW - Salpingitis

KW - Peritonitis

KW - Broiler breeders

KW - Genetic diversity

KW - Virulence profiles

U2 - 10.1016/j.vetmic.2012.11.008

DO - 10.1016/j.vetmic.2012.11.008

M3 - Journal article

C2 - 23201240

SN - 0378-1135

VL - 162

SP - 873

EP - 880

JO - Veterinary Microbiology

JF - Veterinary Microbiology

IS - 2-4

ER -