78 MEDICAL BACTERIOLOGY 



of the influenza bacillus appears to be exalted by symbiotic development with 

 staphylococcus aureus, pneumococcus and streptococci. 



Diagnosis. Whether the infection is localized in the upper air passages, or 

 other parts are involved, the organism can usually be found in the nasal secre- 

 tions and on the nasal mucosa of infected persons. It is present in the sputum 

 when the bacillus of influenza produces pneumonia and in the spinal fluid when 

 the infection affects the meninges. Smears stained by Gram's method and cul- 

 ture on blood-smeared agar usually suffice to establish the diagnosis. In 

 doubtful cases inoculation of rabbits and guinea-pigs is of value. 



When, as often occurs, the staphylococcus, pneumococcus or streptococcus 

 is present in-nasal secretion, sputum or spinal fluid, together with the influenza 

 bacillus, they suggest a more serious condition than uncomplicated influenzal 

 infection. 



KOCH-WEEK'S BACILLUS 



Koch-Week's bacillus, sometimes called the bacillus of acute contagious 

 conjunctivitis, found on the conjunctiva and in the lachrymal discharge in cases 

 of acute contagious conjunctivitis, is indistinguishable from the influenza 

 bacillus and is considered to be the same by some authorities. 



BORDET-GENGOU BACILLUS 



Bordet-Gengou bacillus occurs in pure culture in the bronchial mucus and 

 sputum of some cases of whooping-cough during the early days of the disease; 

 later in the disease other organisms may also be present and make its recognition 

 or isolation more difficult. When present in pure culture the bronchial secre- 

 tion shows very many Bordet-Gengou bacilli, swarms of them. 



Morphology. It is a small bacillus, almost as small as the bacillus of in- 

 fluenza; it is oval, sometimes appearing like a coccus; it stains deepest at each 

 end, and large numbers, close together, irregularly arranged, are found in smears 

 from sputum. 



The Bordet-Gengou bacillus stains with the usual anilin dyes and is Gram 

 negative. 



Growth. The Bordet-Gengou bacillus does not grow on plain agar, gelatin 

 or bouillon. Cultures direct from bronchial secretion do not develop so well as 

 subcultures, those which have been cultivated and transplanted several times. 



On Loeffler's blood serum, i per cent, glycerin-potato agar plus 100 per cent, 

 blood serum, serum agar and ascitic fluid agar, growth occurs under aerobic 

 conditions at 37C. Glycerin-potato agar serum medium is the best for first 

 cultures from the throat; subcultures do well on any of the media mentioned. 



Microscopic growth develops on glycerin-potato agar serum in about 48 

 hours. Subcultures show a faint whitish growth which is said to become more 

 abundant after a day or two. 



Diagnosis is based upon a microscopic examination of bronchial secretion 

 or sputum. 



Vaccine therapy has been lauded by some who have employed it but is not 

 in general use. 



