Amoxycillin as an alternative to dihydrostreptomycin sulphate for treating cattle infected with Leptospira borgpetersenii serovar hardjo.
OBJECTIVE
To assess the effect of amoxycillin treatment on urinary excretion of leptospires from cattle infected with Leptospira borgpetersenii serovar hardjo.


METHODS
A chemotherapy trial with controls.


METHODS
Fourteen heifers serologically negative to L hardjo were inoculated with L hardjo via the conjunctival route and assessed for evidence of infection by serological, fluorescent antibody and microbiological tests. Two injections (48 h apart) of amoxycillin at a dose of 15 mg/kg were administered intramuscularly to seven heifers 6.5 weeks after infection; the remaining heifers acted as untreated controls. Later, these seven control group heifers were treated with a single dose of amoxycillin (15 mg/kg). Samples of urine were collected before and after amoxycillin treatments; kidneys were collected at slaughter, and examined by fluorescent antibody test and microbiological culture.


RESULTS
Leptospires were isolated from the urine of 11 of 14 heifers inoculated with L hardjo. After treatment of six of these with two injections of amoxycillin, leptospires were not isolated. Of the controls, four of the five initially leptospiruric heifers continued to shed leptospires; after a single injection of amoxycillin, no leptospires were detected in the kidneys of these four.


CONCLUSIONS
Amoxycillin may be an acceptable alternative to dihydrostreptomycin sulphate for the treatment of cattle infected with L hardjo.
Smith
C R
CR
Dayboro Veterinary Surgery, School of Veterinary Science, University of Queensland.
Corney
B G
BG
McGowan
M R
MR
McClintock
C S
CS
Ward
W
W
Ketterer
P J
PJ
D000658:Amoxicillin / Q000008:administration & dosage / Q000627:therapeutic use*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D000907:Antibodies, Bacterial / Q000032:analysis / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood / Q000188:drug therapy* / Q000453:epidemiology; D004096:Dihydrostreptomycin Sulfate / Q000008:administration & dosage / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004350:Drug Residues; D005260:Female; D007273:Injections, Intramuscular / Q000379:methods / Q000662:veterinary; D007668:Kidney / Q000382:microbiology / Q000473:pathology; D007919:Leptospira / Q000276:immunology / Q000302:isolation & purification*; D007922:Leptospirosis / Q000097:blood / Q000188:drug therapy / Q000662:veterinary*; D010406:Penicillins / Q000008:administration & dosage / Q000627:therapeutic use*; D011793:Queensland / Q000453:epidemiology
D000900:Anti-Bacterial Agents; D000907:Antibodies, Bacterial; D010406:Penicillins; D000658:Amoxicillin; D004096:Dihydrostreptomycin Sulfate