PERTUSSIS 



2/z long and tend to occur in pairs or short chains. Some claim that 

 they are Gram-positive. 



Culturally the formation of little pits of liquefaction in Loffler's serum within 

 twenty-four hours which later become confluent may be regarded as fairly character- 

 istic. They do not grow on nutrient agar. 



After two or three days on blood-serum rather marked involution 

 forms occur. While usually causing a more or less chronic conjuncti- 

 vitis they may at times produce a keratitis. 



NOTE. A Gram-negative bacillus which is less than i micron long, growing singly, 

 or in pairs, and known as the bacillus of Zur Nedden has been stated to produce 

 corneal ulcers. It grows readily on agar or other ordinary culture media. It 

 coagulates milk. 



Bacillus of Chancroid (Ducrey, 1889). These are short coccobacilli, 

 occurring chiefly in chains. They show bipolar staining. They grow 

 best in a mixture of blood and bouillon. 



Material for culturing should be obtained before the lesion ulcerates. The 

 exudate should be inoculated on blood agar, i part blood to 2 of agar. After forty- 

 eight hours small glistening colonies develop which easily slide about the slant when 

 touched with a loop. 



Bacillus of Bordet-Gengou. This bacillus was reported as the cause 

 of whooping-cough by Bordet and Gengou in 1906. (Czaplewski and 

 Reyher had previously reported oval bipolar staining organisms, as the 

 cause of pertussis, and other authors influenza-like organisms.) 



The bacillus is oval, Gram-negative, shows bipolar staining, somewhat resembles 

 B. influenza and grows only on uncoagulated serum media, as blood or ascites agar. 

 The original cultures are very scanty so that the colonies are difficult to recognize. 

 In subcultures the growth is more flourishing. The organism is only found in white, 

 thick, leukocyte abounding sputum, of the beginning of the disease. Hence per- 

 tussis is probably contagious only at the onset. 



Complement binding and agglutination reactions have been obtained. For 

 diagnosis stain the sputum. Remember that pertussis gives a mononuclear leuko- 

 cytosis of 15,000 to 50,000. 



For isolation from sputum the following medium is required. Auto- 

 clave 500 grams potato with 1000 c.c. of 4% glycerine solution. Pour 

 off excess of fluid. Emulsify potato in 1 500 c.c. normal salt solution and 

 add powdered agar to 3 or 4%. For use mix with an equal quantity 

 of defibrinated blood. 



