04 STUDY AND IDENTIFICATION OF BACTERIA 



It is well to remember that insignificant staphylococcal infection may lead to sep- 

 ticaemia. In the tropics, where resistance is often lowered and staphylococcal skin 

 infections common, continued fevers are often septicaemias. It is the organism 

 most frequently concerned in terminal infections. The lowered resistance of the 

 patient permits of their passage through barriers ordinarily resistant. Not only 

 should this be kept in mind when such organisms are isolated at an autopsy, but 

 as well the fact that their entrance may have been agonal or subsequent to death. 

 Vaccines have been most successful in the treatment of staphylococcal infections. 

 They stimulate phagocytosis. Pyelitis may be due to staphylococci. 



The Pneumococcus of Fraenkel. (Pasteur and Sternberg in 1880. 

 Fraenkel, 1884, isolated it from normal persons as well as pneumonia 

 patients. Inoculated mice and rabbits. Hence FraenkePs organism. 



FIG. 14. Pneumococcus, showing capsule, from pleuritic fluid of infected rabbit, 

 stained by second method of Hiss. (Mac Neal.} 



Weichselbaum accurately differentiated organisms causing pneumonia 

 in 1886.) This is by far the most common cause of pneumonia, whether 

 it be of the croupous, catarrhal, or septic type. It is also frequently 

 found in meningitis, empyema, endocarditis and otitis media. It 

 should not be confused with the pneumobacillus of Friedlander, which, 

 although possessing a capsule like the Pneumococcus, differs from it by 

 being Gram-negative, being a bacillus and having large viscid colonies. 

 The Pneumococcus is the cause of more than 80% of the cases of 

 pneumonia. 



It does not grow below 2oC. and is best cultivated on blood-serum, or blood- 

 streaked agar. On plain agar it grows as a very small dew-drop-like colony, which 



