Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: February 9, 2001
Publication Date: May 20, 2001
Citation: Cray, P.J., Bailey, J.S., Ladely, S.R., Cosby, D.E., Hall, M.C., Haro, J.H. 2001. Effect on resistance in salmonella species following use of gentamicin in ovo. American Society for Microbiology. Session No. 245. Abstract. C-404. P. 245. Technical Abstract: The development of antimicrobial resistance is a global problem. Poultry are known to be a source of zoonotic bacteria, particularly Salmonella. Eggs are routinely inoculated with Marek's vaccine prior to hatch and incorporation of Gentamicin reduces chick mortality associated with vaccination. Eggs were placed in one of four groups (n=132/group). Groups 1 and 3 were not given Gentamicin (g) while Groups 2 and 4 eggs were inoculated with 0.4 mg Gentamicin/egg. Following hatch, 12 birds/group were necropsied. Birds from Groups 3 and 4 were commingled with seeder birds which had been challenged with 10**6 CFU each of Salmonella (s) and Campylobacter (c). Birds (n=40/group) were necropsied at weeks 2, 4, and 6. The ceca from all birds was harvested and cultured for Salmonella and generic E. coli. The total prevalence of Salmonella per group was 9%, 0%, 40% and 56% for Groups 1 - 4, respectively. Salmonella isolates were examined for resistance to Gentamicin as per the protocol established for the NARMS program. Only 1/7 (14%) isolates was resistant to Gentamicin in Group 3 (s+c+g-) while 2/49 (4%) and 3/49 (6%)isolates had intermediate resistance from Groups 1 (s-c-g-) and 4 s+c+g+), respectively. Only the E. coli isolates which were recovered from the same birds which were salmonella positive were tested for resistance to Gentamicin. 3/6 (50%), 23/46 (50%) and 22/28 (79%) of isolates from Groups 1, 3 and 4 were Gentamicin resistant, respectively. These data suggest that use of Gentamicin does not affect the prevalence of Salmonella and does not appear to affect the development of Gentamicin resistance in Salmonella or generic E. coli.