CHARACTERISTICS AND BIOTYPES OF PASTEURELLA-MULTOCIDA ISOLATED FROM HUMANS

Pasteurella isolates (48 strains of P. multocida and 4 strains of atypical Pasteurella) were identified by conventional and commercial test systems. All strains fermented glucose, sucrose and fructose in purple broth base with bromocresol purple as indicator, although the atypical Pasteurella produced fermentation reactions that were barely perceptible. Eleven different biotypes were identified by fermentation reactions in maltose, mannitol, xylose, sorbitol and trehalose media. There was a correlation of biotypes to cat bites, with 61% of cat bite isolates falling into biotype A and B. A correlation of biotype and dog bite isolates was not seen. The choice of medium used for fermentation tests was critical as evidenced by the inability of the organisms to grow in a 2nd commercially purchased preparation of purple broth base. The reliability of commercial test systems in identifying Pasteurella was 81% for Oxi/Ferm, 68% for API and 11% for Minitek.