Antibiotic resistance of gram-negative enteric bacteria from pigs in three herds with different histories of antibiotic exposure.
The antibiotic resistance patterns of gram-negative fecal bacteria from pigs in three herds with different histories of antibiotic exposure were examined. In general, smaller proportions of antibiotic-resistant or multiply resistant fecal isolates (P less than 0.05) were obtained from pigs in a herd not exposed to antimicrobial agents for 154 months than from pigs in a herd continuously exposed to antimicrobial agents at subtherapeutic doses or from pigs in a herd exposed only to therapeutic doses of antimicrobial agents. The proportions of antibiotic-resistant and multiply resistant strains were greater among isolates from pigs in the therapeutic herd than in the non-antibiotic-exposed herd (P less than 0.05). The proportion of antibiotic-resistant isolates in the non-lactose-fermenting population was greater than that in the lactose-fermenting population, regardless of herd. The results suggest that any form of antimicrobial exposure will increase the prevalence of antimicrobial resistance and multiple resistance of fecal bacteria.
Gellin
G
G
Department of Animal Sciences, University of Kentucky, Lexington 40546-0215.
Langlois
B E
BE
Dawson
K A
KA
Aaron
D K
DK
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001424:Bacterial Infections / Q000188:drug therapy; D004352:Drug Resistance, Microbial / Q000235:genetics; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D005285:Fermentation; D007785:Lactose / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D009154:Mutation; D012007:Rectum / Q000382:microbiology; D013552:Swine
D000900:Anti-Bacterial Agents; D007785:Lactose