56 ELEMENTARY BACTERIOLOGY LABORATORY . EXERCISES 
SECTION 19: BACTERIOLOGY OF DISEASE 
EXERCISE 83 
STUDY OF PYOGENIC STAPHYLOCOCCI 
A number of pyogenic (pus producing) infections, such as boils, carbuncles, 
abscesses, etc., are caused by staphylococci. The most important of these are 
Staphylococcus albus and Staphylococcus aureus. 
From cultures of Staphylococcus albus and Staphylococcus aureus inoculate: 
(1) agar slope, (2) nutrient broth, (3) gelatin stab, (4) brom cresol purple glu- 
cose, lactose, and sucrose broths in Durham tubes, and (5) litmus milk and brom 
cresol purple milk. 
Incubate all cultures, except the gelatin, at 37° C. 
Make morphological studies using Gram’s stain. 
EXERCISE 84 
STUDY OF STREPTOCOCCUS PYOGENES 
Streptococcus pyogenes is the common cause of pyogenic infections, such as 
boils, carbuncles, and abscesses; wound infections; inflammation of mucous mem- 
branes, such as tonsilitis; and infections of internal organs, as in certain cases 
of appendicitis and endocarditis. Other closely related streptococci are responsible 
for a number of diseases in man and animals; some examples of which are 
Streptococcus scarlatinae, cause of scarlet fever; Streptococcus erysipelatis, the 
cause of erysipelas; Streptococcus equi, the cause of strangles in horses; Strepto- 
coccus mastitidis, the cause of inflammation of the udder or garget in cattle. 
From the culture of Streptococcus pyogenes inoculate: (1) agar slope, (2) nu- 
trient broth, (3) gelatin stab, (4) brom cresol purple glucose, lactose, and sucrose 
broths in Durham tubes, and (5) litmus milk and brom cresol purple milk. 
Incubate all cultures, except the gelatin, at 37° C. 
Make morphological studies using Gram’s stain. 
EXERCISE 85 
STUDY OF CORYNABACTERIUM DIPHTHERIA 
From a culture of the diphtheria organism make stained microscopic prepa- 
rations, using methylene blue, Study carefully and observe for the presence of 
cells showing irregular staining and variations in morphology. 
