The effects of danofloxacin and tilmicosin on neutrophil function and lung consolidation in beef heifer calves with induced Pasteurella (Mannheimia) haemolytica pneumonia.
Pneumonia caused by Pasteurella (Mannheimia) haemolytica was induced in weaned beef heifer calves, approximately 6 months of age. Calves were treated at 20 h after challenge with therapeutic doses of danofloxacin or tilmicosin. Peripheral blood neutrophils were collected at 3, 24 and 48 h after treatment. The ex vivo effects on neutrophil function, neutrophil apoptosis, and hematological parameters were examined, as was the effect on percentage lung consolidation. Neutrophil function assays included random migration under agarose, cytochrome C reduction, iodination, Staphylococcus aureus ingestion, chemotaxis, and antibody-dependent and antibody-independent cell-mediated cytotoxicity. Apoptosis was determined using a cell death detection kit. Killing was performed at 72 h after treatment. Statistical comparisons were made among the three groups of challenged-treated animals: saline, danofloxacin, and tilmicosin. Comparisons were also made between nonchallenged nontreated animals (NCH) and challenged saline-treated animals. There were no significant differences for any of the neutrophil function assays or neutrophil apoptosis among the challenged-treated groups. This suggests that danofloxacin and tilmicosin have no clinically significant effects on neutrophil function or apoptosis. There were also no significant differences in percentage lung consolidation among the challenged-treated groups. Significant differences were found between the NCH calves and the challenged saline-treated calves in several neutrophil assays, which were attributed to effects of P. haemolytica infection.
Fajt
V R
VR
Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University College of Veterinary Medicine, Ames, IA 50010-3020, USA. fajt@iastate.edu
Apley
M D
MD
Roth
J A
JA
Frank
D E
DE
Brogden
K A
KA
Skogerboe
T L
TL
Shostrom
V K
VK
Chin
Y-L
YL
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D002417:Cattle; D024841:Fluoroquinolones; D007279:Injections, Subcutaneous / Q000662:veterinary; D008168:Lung / Q000187:drug effects / Q000382:microbiology / Q000473:pathology; D018942:Macrolides; D016978:Mannheimia haemolytica / Q000187:drug effects* / Q000472:pathogenicity; D008826:Microbial Sensitivity Tests; D009504:Neutrophils / Q000187:drug effects* / Q000382:microbiology; D012766:Pasteurellosis, Pneumonic / Q000188:drug therapy* / Q000473:pathology; D010587:Phagocytosis / Q000187:drug effects; D015645:Tylosin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology* / Q000627:therapeutic use
D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D018942:Macrolides; C068581:danofloxacin; C052319:tilmicosin; D015645:Tylosin