P-044. Analysis of Campylobacter Plasmids from Different Hosts

E. M. L. Johnson, M. K. Fakhr, S. R. Petermann, J. S. Sherwood, C. M. Logue;
North Dakota State Univ., Fargo, ND.

Campylobacter is a leading cause of bacterial gastroenteritis worldwide. Poultry is considered the primary foodborne source of this pathogen; however cattle, pigs, and sheep are also carriers. Plasmids in a range of sizes have been detected in Campylobacter recovered from humans and food production animals. Although plasmids can contribute to both virulence and antimicrobial resistance, the roles of Campylobacter plasmids are not well understood. This study was conducted to determine the prevalence of plasmids in Campylobacter spp. from various hosts. Plasmid carriage of virB11, a gene present on the Campylobacter virulence plasmid pVir, was also investigated. Campylobacters (n=120) recovered from humans, turkey, pigs, and cattle were screened for plasmids using a modified phenol-chloroform extraction method or Qiagen kits. Plasmids obtained were analyzed by restriction enzyme digestion with BglII and PstI. Among the isolates from each source, the percentage of isolates with plasmids and the approximate plasmid sizes obtained were: turkey, 90%, 50-100 kb; cattle, 85%, 2-70 kb; pig, 75%, 3-95 kb; and human, 48%, 37-85 kb. Restriction digestion profiles of plasmid DNA from the same hosts and between different hosts were variable. Southern hybridization using a virB11 probe was conducted to determine if this gene was located on selected plasmids. Interestingly, hybridization analysis showed that some plasmids from turkey carry virB11. Isolates were also analyzed for susceptibility to azithromycin, ciprofloxacin, clindamycin, erythromycin, florfenicol, gentamicin, nalidixic acid, telithromycin, and tetracycline using broth microdilution. Tetracycline resistance rates were highest among isolates originating from turkey (100%), followed by cattle (61%), pigs (57%), and humans (55%). Our results indicate that plasmids are prevalent among human and animal Campylobacter isolates and plasmid profiles tend to vary by host. Conjugation assays are in progress to assess plasmid mobility. Further investigation of these plasmids will aid in understanding their role in Campylobacter.