title: Evaluation of antibiotics for treatment of cattle infected with Leptospira borgpetersenii serovar hardjo.
abstract: OBJECTIVE
  To evaluate antibiotics for treatment of cattle with leptospirosis caused by Leptospira borgpetersenii serovar hardjo.
  
  
  METHODS
  Randomized controlled trial.
  
  
  METHODS
  42 healthy mixed-breed cattle.
  
  
  METHODS
  Cattle were inoculated via conjunctival instillation with L. borgpetersenii serovar hardjo. After infection and urinary shedding of L. borgpetersenii were confirmed, cattle were treated with various antibiotics. To determine effectiveness of antibiotic treatment, urinary shedding of L. borgpetersenii was monitored for 4 to 6 weeks after administration of antibiotics, using darkfield microscopic examination, microbial culture, immunofluorescence testing, and a polymerase chain reaction assay.
  
  
  RESULTS
  All inoculated cattle developed leptospirosis and shed leptospires in their urine. The following antibiotic treatments resulted in elimination of urinary shedding of leptospires: a single injection of oxytetracycline (20 mg/kg 19 mg/lb] of body weight, IM), tilmicosin (10 mg/kg [4.5 mg/lb], SC), or a combination product that contained dihydrostreptomycin-penicillin G (25 mg/kg [11.4 mg/lb], IM) or multiple injections of ceftiofur sodium (2.2 or 5 mg/kg [1 or 2.3 mg/lb], IM, once daily for 5 days, or 20 mg/kg, IM, once daily for 3 days).
  
  
  CONCLUSIONS
  Successful resolution of leptospirosis in cattle by administration of dihydrostreptomycin-penicillin G confirms results obtained by other investigators. Three other antibiotics (oxytetracycline, tilmicosin, and ceftiofur) also were effective for resolving leptospirosis and may be useful substitutes for dihydrostreptomycin, an antibiotic that is no longer available for use in food-producing animals in the United States. Cost, safety, and withdrawal times of these various treatment options need to be considered.
authors.affiliation: Bacterial Diseases of Livestock Research Unit, National Animal Diseases Center, USDA, Ames, IA 50010, USA.
authors.forename: D P
authors.initials: DP
authors.lastname: Alt
authors.forename: R L
authors.initials: RL
authors.lastname: Zuerner
authors.forename: C A
authors.initials: CA
authors.lastname: Bolin
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001437:Bacteriuria / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary*; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy* / Q000382:microbiology; D002511:Cephalosporins / Q000494:pharmacology / Q000627:therapeutic use; D004096:Dihydrostreptomycin Sulfate / Q000494:pharmacology / Q000627:therapeutic use; D004359:Drug Therapy, Combination / Q000494:pharmacology / Q000627:therapeutic use; D005260:Female; D005455:Fluorescent Antibody Technique / Q000662:veterinary; D007919:Leptospira / Q000187:drug effects* / Q000254:growth & development; D007922:Leptospirosis / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary*; D018942:Macrolides; D008297:Male; D010118:Oxytetracycline / Q000494:pharmacology / Q000627:therapeutic use; D010400:Penicillin G / Q000494:pharmacology / Q000627:therapeutic use; D016133:Polymerase Chain Reaction / Q000662:veterinary; D016896:Treatment Outcome; D015645:Tylosin / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D018942:Macrolides; C053503:ceftiofur; D010400:Penicillin G; D004096:Dihydrostreptomycin Sulfate; D010118:Oxytetracycline; C052319:tilmicosin; D015645:Tylosin