622 



STAPHYLOCOCCUS 



Potato. — 24 hours, 37° G. Poor, yellowish, effuse growth. 5 days ; moderate, confluent, 

 slightly raised, golden-yellow growth. 



Loeffler's Serum. — 24 hours, 37° C. Good, raised, confluent, golden-yellow growth. 



Resistance. — May withstand moist heat at 60° C. for 30 minutes ; generally killed in one 

 hour. Destroyed by 2 per cent, phenol in 15 minutes. 



Metabolism. — Aerobic, facultatively anaerobic. Growth occurs best at 37° C, limits 12° 

 to 45° C. Optimum pH for growth is 7-4-7-6. Pigment formed most readily at 

 22° C. ; is not formed in ciUtures grown anaerobically. Filtrable hsemolysin pro- 

 duced ; a-lysin acts rapidly on rabbit and sheep red corpuscles ; yS-lysin acts slowly 

 on sheep corpuscles — hot-cold lysis. Coagulase produced which clots citrated human 

 or rabbit plasma. 



Biochemical Reactions. — Acid, no gas, in glucose, maltose, mannitol, lactose, and sucrose. 

 L.M. acid, clot, and sometimes peptonization. Indole — . M.R. -|-. V.P. -f. 

 Nitrates reduced to nitrites. M.B. reduction -|- . HjS — . NH3-J-. 



Antigenic Structure. — Contains a polysaccharide A, demonstrable by precipitation. Divi- 

 sible by agglutination with absorbed sera into three main types and a number 

 of sub -types. 



Pathogenicity. — Forms exotoxin with hsemolytic, leucocytolytic, skin-necrosing, and lethal 

 properties for the rabbit. Some strains also form an enterotoxin acting on man. 

 Staph, aureus is frequently responsible for suppurative lesions in the human body, 

 such as boils and abscesses, acute osteomyelitis, infective endocarditis, pyaemia, 

 etc. Experimentally, it is pathogenic for rabbits, less so for mice and guinea- 

 pigs. 0-1-0-5 ml. of a 24-hours' broth culture injected intravenously into a rabbit 

 is generally fatal in 24 to 48 hours ; post mortem, haemorrhages on the serous 

 membranes ; the cocci can be recovered from the blood stream. A smaller 

 dose may not prove fatal for 1 to 6 weeks ; post mortem, multiple abscesses 

 are frequently seen, especially in the kidneys, less frequently in the myocardium, 

 lungs, spleen, bone marrow, and costal cartilages. 



Staphylococcus albus. — Resembles Staph, aureus in many respects. For chief 

 differences, see p. 621. 



Staphylococcus citreus. — Resembles Staph, aureiis in many respects. For chief 

 difierences, see p. 621. 



TABLE 39 



* Viscid growth in broth. 



