Pasteurella multocida: plasma lysozyme in bacteremic and lipopolysaccharide-exposed turkeys

Plasma lysozyme was measured in turkeys with experimental fowl cholera produced by either of two serotypes of Pasteurella multocida. Lysozyme was not detected in preexposure plasma, whereas plasma sampled when turkeys were terminally bacteremic contained 7.0-7.5 microgram of lysozyme/ml. Plasma lysozyme was measured in turkeys inoculated intravenously with P. multocida lipopolysaccharide (LPS). Turkeys inoculated with 10 microgram of LPS produced plasma lysozyme detectable for 2 hr after inoculation; those inoculated with 500 microgram of LPS produced plasma lysozyme detectable for at least 6 hr after inoculation. Egg-white lysozyme, equivalent in concentration to the plasma lysozyme detected in bacteremic turkeys, was active upon young cultures of P. multocida and increased the degree of lysis of P. multocida cells treated with deoxycholate. Lysozyme, ethylenediaminetetraacetate, and deoxycholate in combination produced the highest degree of lysis of P. multocida cells.