Fingerprinting of poultry isolates of Enterococcus cecorum using three molecular typing methods

Enterococcus cecorum is an emerging challenge to the broiler industry. The organism has been implicated in septicemia, spondylitis, arthritis, and osteomyelitis in commercial broilers and broiler breeders, which lead to economic losses attributed to increased mortality and culling rates, decreased average processing weights, and increased feed conversion ratios. The current study evaluated the genetic variability of 30 clinical isolates of E. cecorum from outbreaks in Pennsylvania, using 3 molecular typing methods, namely, pulsed-field gel electrophoresis (PFGE), randomly amplified polymorphic DNA analysis, and enterobacterial repetitive intergenic consensus-PCR (polymerase chain reaction), in order to understand their genetic relatedness and to identify possible pathogenic clones. The study revealed the existence of genotypic polymorphism among E. cecorum associated with clinical disease. Of the 3 typing methods used, PFGE analysis demonstrated higher genetic variability of E. cecorum isolates compared to PCR-based methods. Also, each molecular typing method was evaluated in terms of typeability, discriminatory power, and reproducibility for application of these typing methods in fingerprinting of E. cecorum in future reference. Pulsed-field gel electrophoresis provided the most reliable results with greater discriminatory power and higher reproducibility compared to the 2 PCR-based methods.