STAPHYLOCOCCUS PYOGENES AUREUS 



153 



by Gram's method. They are not motile; have neither flagella 

 nor spores. 



Oxygen Requirements. The coccus grows well in oxygen, and 

 poorly without it. 



Temperature and Vital Resistance. 

 Thrives best at body temperature, but 

 grows well at room temperature. Resists 

 drying for over one hundred days in pus. 

 Dry thermal death-point is 8oC. for one 

 hour. Moist heat 7oC., kills in ten to 

 twenty minutes. Resists freezing tempera- 

 ture for many months. 



Exceedingly resistant to formaldehyde, 

 more so than some spore-bearing organisms. 

 Resists light also. It is killed by corrosive 

 sublimate i-iooo in fifteen minutes; i per- 

 cent H2C>2 in thirty minutes. 



Chemical Activities. Produces a golden- 

 yellow pigment only under oxygen. Gener- 

 ates acids, but no free gases. Creates indol 

 and sulphuretted hydrogen; ferments urea, 

 and produces ferments that dissolve gelatine, 

 and the coagulated proteids of milk. The 

 toxin is soluble in water, and acts intensely, 

 causing violent local reaction. If in the ab- 

 dominal cavity, it causes peritonitis. Subcu- 

 taneously it may produce sterile abscess, or 

 local necrosis. There is produced in cultures 

 a toxin having a destructive action upon leucocytes and red 

 blood cells. 



Cultures. In gelatine it rapidly forms golden-yellow colonies, 

 that quickly liquefy the gelatine (Fig. 40). Sterile products 

 of the growth also liquefy gelatine. On gelatine plate, yellowish 

 to orange colonies are formed. On agar streak a luxuriant orange 



FIG. 40. Gelatine 

 culture staphylococ- 

 cus aureus one week 

 old. (Williams.) 



