Further characterization of the agent causing coryza in turkeys

A total of 128 isolates of Alcaligenes faecalis, from the respiratory tract of turkeys and chickens, were identified and divided into two types designated type I and type II. Type I isolates were pathogenic in poults, hemagglutinated guinea pig red blood cells (RBCs), and did not grow on minimal essential medium (MEM) agar, and most did not grow in 6.5% NaCl broth. Type II isolates were nonpathogenic and nonhemagglutinating and grew on MEM agar, and most grew in 6.5% NaCl broth. Hemagglutination of guinea pig RBCs was a reliable characteristic for distinguishing type I from type II isolates, and it correlated with pathogenicity. In serological studies using 62 type I and 21 type II isolates, cross-reactions were observed when type I but not type II antigens were used to test antisera in the microagglutination test. Eleven bacterial isolates, different from type I and type II isolates, were urease-positive. Although frequently isolated from turkeys with coryza, these isolates were nonpathogenic and were always found in association with type I A. faecalis. Urease-positive isolates and type I and type II A. faecalis isolates were stable following 50 in vitro passages. Bordetella avium sp. nov. (the nomenclature suggested in Europe for A. faecalis) was pathogenic in poults. The colonial morphology, biochemical characteristics, and hemagglutinating activity of B. avium sp. nov. were the same as those of type I A. faecalis isolates. Based on the results of these studies, it was concluded that type I A. faecalis is the etiologic agent of turkey coryza.