Title: SUPPRESSION OF MANNHEIMIA (PASTEURELLA) HAEMOLYTICA SEROVAR 1 INFECTION IN LAMBS BY INTRAPULMONARY ADMINISTRATION OF OVINE ANTIMICROBIAL ANIONIC PEPTIDE
Kalfa, V - USDA/ARS/NADC, AMES, IA
Palmquist, D - USDA/ARS/MWA, PEORIA, IL
Ackermann, Mark - IA STATE UNIV., AMES, IA
Submitted to: International Journal of Antimicrobial Agents
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 28, 2000
Publication Date: N/A
Interpretive Summary: Respiratory tract diseases are a leading cause of loss from disease in the cattle, sheep, and goat industries. Annual loss in the United States is estimated to exceed one billion dollars. Losses are from mortality, reduced feed efficiency, and slaughter condemnations, as well as prevention and treatment measures. Currently, scientists and veterinarians are looking at novel ways to prevent or treat the disease. As part of our ongoing studies, we hypothesized that antimicrobial anionic peptides, originally isolated from sheep lungs, might be effective in treating bacterial respiratory infections. To test this, we established a model of acute pneumonia in lambs. In infected lambs, a single bronchial instillation of anionic peptide reduced the concentration of bacteria in lung fluid and tissues. Hence, the in vivo effectiveness of anionic peptide suggests that it may have applications in the treatment of pulmonary infections. Corollary benefits include an increase in the profitability and international competitiveness of the U. S. cattle industry, a stronger rural economy, and a continued supply of inexpensive, wholesome beef, and beef products for the American consumer.
In this study, the efficacy of ovine antimicrobial anionic peptide (AP) was assessed in a lamb model of acute pneumonia. A single intratracheal dose of H-DDDDDDD-OH (0.5 mg) reduced pulmonary inflammation and the concentration of Mannheimia (Pasteurella) haemolytica in infected lung tissue. Administration of H-DDDDDDD-OH after infection was more effective in reducing the consolidation and lesion scores at the deposition site than administration of H-DDDDDDD-OH prior to infection. Hence, the in vivo effectiveness of AP suggests that it may have applications in the treatment of pulmonary infections. Further studies are needed to confirm these findings and also to determine the optimal doses and intervals of H-DDDDDDD-OH therapy.