158 MEDICAL BACTERIOLOGY 



The finding of typical rosettes, clubs and filaments establishes the diagnosis. 



When, for more detailed study, cultures are desired the actinomyces must be 

 isolated from other organisms present in the pus. The technique for this is as 

 follows : 



Lift a dozen or more of the granules from the pus and place on gelatin plates ; 

 incubate these plates at 37C. for 2 days; most of the granules will be surrounded 

 with colonies of contaminating bacteria; search for granules free from other 

 bacteria and remove these with a sterile loop and plant on slant tubes of glycerin 

 agar and tubes of Loeffler's blood serum; incubate these tubes at 37C. Many 

 tubes should be planted, as some will show no growth and others will contain 

 organisms other than actinomyces; tubes containing only strep to thrix actino- 

 myces will show growth in 4 to 6 days. 



STREPTOTHRIX MADURA 



Streptothrix madurae is found in the lesions and pus and exudate of a dis- 

 ease known as "madura foot." 



Morphology. Granules removed from lesions, exudate or pus, consist of 

 interlaced, branching filaments. Organisms removed from cultures have the 

 same appearance; in addition they show spores arranged singly, in pairs, and 

 irregular masses. 



Staining readily occurs with the usual anilin dyes. It is Gram positive. 



Growth. Streptothrix madurae is an obligate aerobe and grows best at 

 37C. In bouillon, gelatin, agar, egg and serum growth is scant when it takes 

 place at all. 



Glucose Glycerin Agar. After several days, round, smooth, elevated, 

 yellowish- white colonies appear; as they age they increase in size, become pink 

 and later red. Umbilication may occur or the colonies may coalesce. 



Potato. -Warty colonies develop on this medium; at first white, they gradu- 

 ally change to deep red. 



Milk is not coagulated. 



Hay Infusion. Flocculi form after several days; some precipitate and some 

 float. Those exposed to the oxygen after several weeks turn from white to 

 pink. The medium is not clouded. 



Pathogenesis. Streptothrix madurae causes a chronic productive inflam- 

 matory condition of the foot; associated nodular swellings give a warty appear- 

 ance to the surface. After a time suppuration occurs, followed by spontaneous 

 rupture and sinus formation. The exudate or pus which oozes from the sinus 

 contains small white, yellow or black granules similar to those found in 

 actinomycosis. 



Rarely the hand is affected. The disease has been observed in man only. 

 Animals are immune. 



Diagnosis.- In suspected cases the pus is inspected for granules, and these 

 are stained and examined microscopically. 



Cultures are obtained by asepticizing the skin over a nodule, making an 

 incision and removing some fluid from the nodule with a sterile tube and trans- 

 ferring it to hay infusion or glycerin glucose agar. 



