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THE ACTINOMYCETES, Vol. I 



There were numerous other reports of the 

 occurrence of streptomyces in human or- 

 gans, as m the ear (Odom ct al.), in tumors 

 (Leyton and Leyton), and in tear ducts and 

 glands (Gruter). Mackinnon and Artaga- 

 veytia-Allende (1956) examined 38 strains 

 of aerobic actinomycetes producing locaUzed 

 mycetoma in various zones of the world. 

 They identified these organisms as species 

 of Streptomyces and Nocardia. 



The isolation of Micrornonospora cultures 

 from animal and human cases has also been 

 reported. Morquer and Comby found (1943) 

 M. caballi to be parasitic on the horse, but 

 not on rabbits, rats, or mice. 



Acton and McGuire observed the occur- 

 rence in India of a red actinomycete that 

 produces keratolytic changes in the skin of 

 the hands and feet, causing lesions known as 

 keratolysis plantare sucatum, mango toe, 

 cracked heel, paronychia, onychomycosis, 

 and vesicular eruptions. It is commonly be- 

 lieved that these lesions are caused by walk- 

 ing barefooted on damp soil, particularly soil 

 contaminated by horse manure. The organ- 

 ism was actually recovered from both horse 

 and cow manure; it had a marked lytic action 

 on the horny layer of the epidermis of the 

 soles of the feet and sometimes on the palms 

 of the hand. In culture, the colonies were red 

 or black, with deep mycelium penetrating 

 the media. On microscopic examination the 

 organism showed fine hyphae, about 0.8 /x in 

 diameter. The conidia were small and round, 

 and formed along the course of the aerial 

 hyphae, at the ends or growing out laterally. 

 At first they were single, but in old cultures 

 they were grouped and surrounded the aerial 

 hyphae. The name A. keratolijtica was pro- 

 posed, but a study of the illustrations shows 

 the organism to be a Micromonuspora. The 

 organism causing lumpiness of matted wool 

 in sheep is definitely a Nocardia and not an 

 Actinomyces, as claimed by Bull. 



Heymer (1957) found a Streptomyces (S. 

 coelicolor) in relatively great abundance in 



the microflora of human beings, nota- 

 bly in the sputum, tonsilar crypts, and skin. 

 This organism exerted an antagonistic effect 

 upon \'arious human pathogenic fungi and 

 yeasts. It was suggested that such organisms 

 may play an important role in keeping the 

 microbiological e(iuilibrium in the human 

 })ody. 



Further information, some of which is 

 highly fragmentary, on the causation of dif- 

 ferent animal diseases by actinomycetes is 

 found elsewhere in this treatise, notably in 

 Chapters 24, 25, and 30, Volume II. In other 

 cases, where some degree of certainty exists 

 of the disease causation, the organisms have 

 not been sufficiently studied to enable ascer- 

 tainment of their exact relationship to others 

 now well recognized. The introduction of new 

 systems of classification has complicated fur- 

 ther the i-ecognition of some of the disease- 

 producing forms. It was simple enough when 

 the organisms could be classified under "Ac- 

 tinomyces" or "Streptothrix." It was still 

 relatively simple to place the anaerobes un- 

 der Actinomyces and the aerobes under No- 

 cardia. With the introduction of the newer 

 genera, notably Streptomyces and Micromon- 

 ospora, it became very difficult to decide 

 when an aerobic organism should be placed 

 in the Streptomyces or in Nocardia. In the 

 excellent work of Erikson, for example, the 

 accurate descriptions permit one to decide 

 where certain cultures might preferably be 

 placed. Other, more recent investigators were 

 so uncertain of the systematic position of the 

 particular cultures as to designate them by 

 two generic names, such as Nocardia (Strep- 

 tomyces). Still others (Gordon) were not 

 averse to lumping many cultures, showing 

 only minor variations from one another, un- 

 der a particular species. 



The present discussion ma}' be limited, 

 however, to two types of disease caused by 

 actinomycetes and most frequently desig- 

 nated as actinomycosis and nocardiosis. 



