Studies of the pathogenic avian Haemophili.

The biochemical and physiological characteristics of 35 strains of avian haemophili from 7 countries were examined. All strains required V-factor but not X-factor for growth on artificial media. They produced acid in phenol-red broth containing fructose, glucose, and mannose. Acid production from other carbohydrates was variable or did not occur. Thirty-two strains were pathogenic to chickens. Pathogenicity varied with method of exposure. Hyaluronic acid was found in 9 strains. Hemagglutination of human or chicken erythrocytes was inhibited by its presence. Antimicrobial sensitivity patterns showed all strains to be sensitive to chloromycetin, erythromycin, furoxone, gentamicin, nalidixic acid, neomycin, novobiocin, spectinomycin, and tetracycline.