BIOCHEMICAL AND RIBOTYPIC COMPARISON OF ACTINOMYCES-PYOGENES AND A-PYOGENES-LIKE ORGANISMS FROM LIVER-ABSCESSES, RUMINAL WALL, AND RUMINAL CONTENTS OF CATTLE

Objective-To isolate Actinomyces pyogenes and A pyogenes-like (APL) or ganisms from the ruminal wall and ruminal contents of cattle and compa re them with isolates from liver abscesses from the same animals, usin g ribosomal DNA restriction fragment length polymorphism analysis or r ibotyping. Procedure-Specimens of liver abscesses, ruminal walls, and ruminal contents were collected from 59 cattle at slaughter. All beta- hemolytic, pinpoint colonies that were gram positive, pleomorphic rod- shaped, and catalase negative, and that hydrolyzed casein and gelatin were presumptively identified as A pyogenes and were characterized bio chemically, using an identification kit. The isolates that resembled A pyogenes but fermented mannitol or raffinose, or both, were called AP L organisms. isolates from the ruminal wall and ruminal contents were compared with liver abscess isolates from the same animal by use of ri botyping. Results-Actinomyces pyogenes and APL organisms were isolated more frequently from the ruminal wail than from ruminal contents. Rum inal isolates of A pyogenes and APL had biochemical characteristics si milar to those of the isolates from liver abscesses. Among 6 sets of i solates (4 A pyogenes and 2 APL), 2 isolates from liver abscesses had ribopatterns identical to the corresponding ruminal wail isolates, Als o, the APL organisms isolated from the ruminal content matched with th e corresponding liver abscess isolates for both sets of specimens test ed. Conclusions-The ruminal wail may be the niche for A pyogenes and A PL organisms in the rumen. The genetic similarity, on the basis of rib otyping among isolates from liver abscesses, the ruminal wall, and rum inal contents of the same animal suggests that A pyogenes and APL orga nisms that cause liver abscesses originate from the rumen.