CHAPTER XLIII. 

 STAPHYLOCOCCI PYOGENETES. 



Introduction. 



Section I. The experimental disease, p. 618. 



Section II. Morphology, p. 619. 



1. Microscopical appearance and staining reactions, p. 619. 2. Cultural charac- 

 teristics, p. 619. Staphylococcus pyogenes aureus, p. 619. S. pyogenes albus, p. 620. 

 S. pyogenes citreus, p. 620. 

 Section III. Biological properties, p. 620. 



1. Vitality and virulence, p. 620. 2. Bio -chemical reactions, p. 621. 3. Toxin, 

 p. 622. 4. Vaccination, p. 623. 5. Serum therapy, p. 624. 6. Agglutination, p. 624. 

 Section IV. Detection and isolation of the staphylococci, p. 625. 



Diplococcus crassus, p. 626. 



SINCE the discovery by Pasteur of the Staphylococcus aureus two other 

 pyogenic staphylococci have been described, namely the Staphylococcus 

 pyogenes albus and the StapJiylococcus pyogenes citreus. In their biological 

 properties these three micro-organisms are similar, differing from one another 

 only in the colour of their growths. Rodet and Courmont regard them 

 merely as three races of the same species and this view is probably correct. 

 The three organisms will therefore be described together : the Staphylococcus 

 aureus will be taken as the type and the characteristics by which the other 

 two varieties are differentiated from it will be noted in the proper places. 



The pyogenic staphylococci are very widely distributed in nature, and are found 

 in the air and sometimes in water, and in man on the skin and mucous membranes,, 

 under the finger nails, and in the alimentary canal. 



Staphylococci are always present in the mouth : the organisms found in this 

 situation and described by Biondi as Micrococcus salivarius pyogenes, albus and 

 aureus, are identical with the StapJiylococcus albus and aureus respectively. 



In human pathological lesions they are frequently found in pus, especially in 

 furunculosis, osteo-myelitis (Pasteur), abscesses in various parts of the body, etc. 

 Occasionally the Staphylococcus enters the blood stream giving rise to a purulent 

 infection known as pyaemia. 



The pyogenic staphylococci are found in the lesions of suppurative pleurisy, 

 pericarditis and peritonitis, and also in ulcerative endocarditis : they are the cause 

 of some cases of broncho-pneumonia, of inflammatory conditions of the throat, 

 bronchitis, coryza, etc. They are frequently associated with the tubercle bacillus 

 in pleurisy and suppurative meningitis : they complicate infections with the trico- 

 phyton parasites, and are often associated with the pneumococcus in pneumonia 

 and with the diphtheria bacillus in diphtheria : they favour the germination of the 

 spores of the bacillus of malignant oedema (Besson), of the bacillus of hospital gangrene 

 (Vincent), of the bacillus of influenza (Grassberger), and of some other organisms. 



