WOUND INFECTION 5 
Bacteria causing wound infection. A number of species of bacteria 
and a few fungi are included among the organisms that are known 
to produce wound infections 
in animals. Usually, how- 
ever, the forms encountered 
are Micrococcus pyogenes, 
Streptococcus pyogenes, Bacillus 
pyogenes,* Bacillus pyogenes 
Suis (Grips), Bacillus pyogenes 
bovis (Ktimnemann), afew other 
bacilli, more especially those 
belonging to the colon group, 
and a few species of the genus 
pseudomonas. Fungi, especi- 
ally the actinomyces, are 
rarely found in acute wound 
infections. Protozoa are very 
rare excepting in specific dis- 
eases which they cause and 
where their entrance to the 
body is by means of the bites 
of insects. It is true in the 
domesticated animals as in 
man, that the pyogenic bac- 
teria are the most common 
onl 
Fic.1. WOUND INFECTION. A SECTION FROM : ‘ 
THE WALL OF AN ABSCESS IN A HORSE cause of wound infection. In 
SHOWING THE INFILTRATION OF THE IN- 
TERMUSCULAR TISSUE WITH Pus cor- OPN wounds they are often 
PUSCLES. DRAWING MADE WITH] 1INcH associated with a number of 
OCULAR AND 2-3 INCH OBJECTIVE. ordina: ry saprophytic bactera.. 
Frequently in closed lesions nonpathogenic organisms are present in 
*Holt considers B. pyogenes to be identical with the bacillus of polyarthritis de- 
scribed by von Pods in 1897. He has found it present in a number of inflammations 
in animals which deviated somewhat from those caused by other pyogenic bacteria. 
These inflammations are characterized by their chronic and slow course and they 
are rarely followed by pyemia. The lesions differ from other abscess forming inflamma- 
tions in that before the necrosis of the tissue occurs, a distinct proliferation of the same 
takes place which leads to the formation of a tumorlike swelling. According to 
Grips, “The development of the abscess begins with the formation of small. solid 
tubercles of a spherical or linseed shape. These tubercles consist of a yellowish, 
hard tissue and show on section at the beginning, a symmetrical structure. In some- 
what larger tubercles one can recognize two zones, a yellow center and a gray-white 
periphery. At the beginning of the purulent dissolution which sets in at the central 
part one sees small drops of pus come out under pressure. The abscess consists of 
a strong indurated capsule and thick viscid pus of greenish or yellowish green color. 
This organism has been found in a variety of pathological conditions in swine and cat- 
tle. In swine it seems to be intimately associated with arthritis. It is suggested by 
this work that B. pyogenes may be an important factor in many morbid conditions 
that thus far have not been ascribed to any specific organism. 
