210 MEDICAL BACTERIOLOGY 



ARTHRITIS 



Most cases of arthritis are due to infection. It is generally believed that the 

 atria of infection in most cases is through the tonsils or teeth. When tonsillar 

 or mouth infection and arthritis coexist, the cause of the arthritis is sometimes 

 sought for in cultures obtained from the tonsils; such conclusions are quite as apt 

 to be erroneous as correct. 



The offending organism can sometimes, but not always, be found in fluid or 

 pus aspirated from the diseased joint, and an attempt to do so should be made 

 when bacteriological diagnosis is attempted. 



In nearly all cases of arthritis caused by staphylococci, streptococci or the 

 pneumococcus, careful search will reveal the presence of enlarged glands adjacent 

 to the affected joint. The offending organism can be found in these if the follow- 

 ing procedure is carried out so carefully that contamination of the gland with 

 extraneous bacteria is precluded: 



Asepticize the skin overlying the enlarged gland, incise the skin and remove 

 the gland, place the gland in a sterile mortar and emulsify it with sterile water, 

 plant on slant tubes of agar, blood-agar and ascitic fluid agar, also make deep 

 stab cultures in tubes containing agar and blood-agar to the depth of 6 inches. 

 Incubate aerobically at 37C. 



Inject the remaining portion of gland emulsion into the peritoneal cavity of 

 a guinea-pig. 



It is to be remembered that a large number of "rheumatic" manifestations, 

 muscular as well as arthritic, are due to syphilis and that the Wassermann test is 

 positive in 75 per cent, or more of these syphilitic cases. 



The gonococcus complement fixation test will often establish the diagnosis, 

 in cases of gonococcus arthritis, when other means fail. 



In tubercular arthritis the tubercle bacillus is practically never found in 

 slides or cultures made from the fluid or pus; animal inoculations sometimes give 

 positive results. In suspected cases of tubercular arthritis, when other means of 

 diagnosis fail, when there is no contraindication, a tuberculin test should 

 be made. 



