CHAPTER XLIII 



ELECTIVE LOCALIZATION OF BACTERIA 

 IN THE ANIMAL BODY 



EDWARD C. ROSENOW 



The Mayo Foundation, Rochester, Minnesota 



The problem of elective localization of bacteria in the animal body embraces an 

 important part of the whole question of virulence and the causation of disease by bac- 

 teria. In its broader application, the term "elective localization" has been used to 

 designate specific invasive or localizing power of the causative micro-organisms in 

 various diseases. Besredka'' speaks of elective localization of Bacillus dysenteriae and 

 its toxin in the intestines and central nervous system; of Bacillus anthracis and Staph- 

 ylococcus aureus in the skin in anthrax and furunculosis, respectively. The localiza- 

 tion of the Bacillus diphtheriae in the throat, of the virus of rabies in the brain, and 

 of the virus of poliomyelitis in the motor cells of the spinal cord may also be said to be 

 truly elective. The mere entrance of bacteria into the blood stream is not always suf- 

 ficient to cause metastatic disease. Certain delicately balanced conditions must be 

 fulfilled in order to promote localization and growth so that lesions may be produced 

 in various tissues or organs. Thus, in typhoid fever, the blood is invaded by the ty- 

 phoid bacillus, yet localization and lesions remain limited to the lymphoid elements 

 of the intestines and spleen. The pneumococcus commonly invades the blood in lobar 

 pneumonia, yet the lesions tend to remain limited to the lung and pleura. An extreme 

 example of the tendency of bacteria to localize and produce lesions electively in the in- 

 fected host in spontaneous disease is found in subacute bacterial endocarditis. Here 

 green-producing streptococci have been demonstrated in the blood daily or on al- 

 ternate days for many weeks and yet, in most instances, localization remains limited 

 to the valves of the heart, and when other manifestations of localization occur, such 

 as in the tips of fingers and joints, they are usually temporary. Evidence of similar 

 extreme electivity was found in a series of experiments performed long ago in which it 

 was shown that green-producing streptococci localized and produced lesions in the 

 heart valves and hemolytic streptococci in the joints of animals injected intravenously 

 with known mixtures of these organisms. 



In a more limited sense the term "elective localization" has been used to designate 

 the tendency of certain bacteria, especially streptococci, from various localized areas 

 of infection or more normal mucous membranes (such as the nasopharynx) or system- 

 ic lesions, to localize and produce lesions in animals corresponding to those in patients 

 or animals from whom the micro-organisms were isolated.- The idea that different 

 diseases might be due to a single member of the pneumococcus-streptococcus group 

 having different elective localizing power had its birth in my experiments from 191 j 



' Besredka, Alexandre: Local Immunization. Baltimore: Williams & Wilkins, 1927. 



* Rosenow, E. C: J.A.M.A., 65, 1687. 1915. 



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