title: Effect of nitrofurazone or novobiocin on Salmonella enteritidis cecal colonization and organ invasion in Leghorn hens.
abstract: Nitrofurazone (433 mg/liter drinking water) administration to leghorn laying hens for 72 hours with a 48-hour withdrawal period before nitrofurazone-sensitive Salmonella enteritidis challenge resulted in a S. enteritidis culture-positive rate significantly (P less than 0.05) higher than that of unmedicated controls when hens were cultured 6 days following challenge. In a similar experiment, simultaneous nitrofurazone administration and S. enteritidis challenge resulted in no significant differences in S. enteritidis isolation frequency. However, unchallenged nitrofurazone-medicated contact control hens showed a significantly higher S. enteritidis culture-positive rate than the unchallenged unmedicated controls. This increase in apparent S. enteritidis susceptibility was associated with significantly lower cecal propionic acid and fewer anaerobic colony-forming units (CFU). In a third experiment, nitrofurazone treatment had no effect when the antibiotic was withdrawn 72 hours before S. enteritidis challenge. In a subsequent experiment, novobiocin (385 mg/kg) or nitrofurazone (300 mg/kg) was administered to adult hens for 7 days before challenge with nitrofurazone and novobiocin-resistant S. enteritidis. Both nitrofurazone and novobiocin administration resulted in a significantly higher S. enteritidis culture-positive rate than unmedicated controls at end of the experiment 7 days post-challenge. Results indicate that administration of some antibiotics may enhance susceptibility to S. enteritidis in leghorn hens.
authors.affiliation: Department of Poultry Science, Texas A&M University, College Station 77843.
authors.forename: J G
authors.initials: JG
authors.lastname: Manning
authors.forename: B M
authors.initials: BM
authors.lastname: Hargis
authors.forename: A
authors.initials: A
authors.lastname: Hinton
authors.forename: D E
authors.initials: DE
authors.lastname: Corrier
authors.forename: J R
authors.initials: JR
authors.lastname: DeLoach
authors.forename: C R
authors.initials: CR
authors.lastname: Creger
mesh_terms: D000818:Animals; D001421:Bacteria, Anaerobic / Q000187:drug effects; D002432:Cecum / Q000737:chemistry / Q000187:drug effects / Q000382:microbiology; D002645:Chickens; D005232:Fatty Acids, Volatile / Q000032:analysis; D005260:Female; D009583:Nitrofurazone / Q000494:pharmacology / Q000627:therapeutic use*; D009675:Novobiocin / Q000494:pharmacology / Q000627:therapeutic use*; D011201:Poultry Diseases / Q000188:drug therapy / Q000382:microbiology; D012481:Salmonella Infections, Animal / Q000188:drug therapy* / Q000382:microbiology; D012477:Salmonella enteritidis / Q000187:drug effects* / Q000502:physiology
chemical_list: D005232:Fatty Acids, Volatile; D009675:Novobiocin; D009583:Nitrofurazone