Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: 2/21/2003
Publication Date: 4/20/2003
Citation: BROGDEN, K.A., ACKERMANN, M.R., WELSH, M.J., ZABNER, J. XYLITOL ACTIVATED INNATE IMMUNITY SUPPRESSES PULMONARY MANNHEIMIA HAEMOLYTICA INFECTIONS IN SHEEP. 103rd GENERAL MEETING OF THE AMERICAN SOCIETY FOR MICROBIOLOGY. 2003. Abstract p. 250, #E-006.
Technical Abstract: Osmolytes with low transepithelial permeability administered to mucosal surfaces, (e.g., the respiratory tract) during experimental challenge may lower the ionic strength of the interstitial fluids and increase the activity of endogenous antimicrobial proteins and peptides. To test this hypothesis, lambs were randomized to 8 groups of 3 and lightly sedated. Mannheimia haemolytica at concentrations of 10**6 to 10**9 CFU in 300 mM xylitol were instilled into the caudal portion of the right cranial lobe of the lungs in half the groups. Identical concentrations of M. haemolytica in 1 ml 300 mM NaCl were similarly instilled into the lungs of sheep in the other groups. Twenty minutes postinoculation (PI), the inoculation sites of all lambs were lavaged with 100 ml saline, and concentrations of live M. haemolytica were determined by quantitative plate counts. At 24 hours PI, all lambs were euthanized for necropsy. The inoculation site was again lavaged for quantitative bacterial culture, and tissue was collected from the pulmonary deposition site for histopathological examination of lesions and quantitative bacterial culture. Mannheimia haemolytica in 1 ml 300 mOsm xylitol was more readily cleared at 20 minutes and 24 hours than M. haemolytica in 1 ml 300 mOsm NaCl. The effect of xylitol in this model appeared to be dependent upon the concentration of M. haemolytica instilled; preliminary work with a small number of lambs suggested that xylitol had a significant enhanced airway clearance at 20 minutes and 24 hours when the bacterial inocula was 10**7 CFU or less. These studies suggest that xylitol enhances bacterial killing in the lung.