VII. IDENTIFICATION OF ATYPICAL MYCOBACTERIA
329
M . avium and M. intracellulare have identical biochemical properties.
They give a negative result in the Tween-hydrolysis and the nitrate reductase tests.
E. Mycobacterium scrofulaceum
M . scrofulaceum was described by Prissick and Masson (1956) as the
causative agent of cervical lymph node infections in children. It is scotochromogenic, fails to hydrolyse Tween-80 or reduce nitrate, but is, in
contrast to M. intracellulare, urease positive. The negative result of the
Tween-hydrolysis test distinguishes M. scrofulaceum from the saprophytic
scotochromogens.
M. scrofulaceum has three serotypes with the numbers 41,42 and 43. The
original names of these types were Scrofulaceum, Lunning and Gause
(Schaefer, 1968).
F. Mycobacterium xenopi
M. xenopi was isolated by Schwabacher (1959) from a toad. Its occurrence in human infections was reported by Marks and Schwabacher
(1965). It is very slow growing and forms microcolonies at 37°C. Its
optimal growth temperature range is 4245°C. The colonies are yellow and
give positive results on the three-day arylsulphatase test. I n contrast to
M . intracellulare, M . xenopi is sensitive to Streptomycin, Isoniazid and
Ethionamide (Bretey and Boisvert, 1969).
M . xenopi has been differentiated serologically from other types of mycobacteria in the agar double diffusion (Beck and Stanford, 1968)) and complement fixation tests (Kantor et al., 1970). Differentiation is also possible
by chromatographic analysis of lipids (Jenkins et al., 1972). Whether M.
xenopi can be differentiated from other microcolony forming and nonpigmented mycobacteria is not yet known.
G. Mycobacterium simiae
The name was originally given to a group of atypical poorly growing
photochromogenic mycobacteria isolated from monkeys (Karassova et al.,
1965). Some of these strains were niacin-positive (Weiszfeiler et al., 1971).
Valdivia et al. (1971) reported the isolated of niacin-positive Runyon group
I11 strains resembling mycobacteria from sputa in Cuba and named them
M. habana. Meissner and Schroeder (1975) found the niacin-positive
strains of Weiszfeiler and Valdivia to be culturally and antigenically
identical and designated them as M . simiae type 1. This type differed from
M . intracellulare by giving positive results in the niacin and urease tests by
exhibiting delayed photochromogenicity, and by being specifically agglutinated by M . simiae antisera. M . simiae 1 has been found repeatedly in
329
M . avium and M. intracellulare have identical biochemical properties.
They give a negative result in the Tween-hydrolysis and the nitrate reductase tests.
E. Mycobacterium scrofulaceum
M . scrofulaceum was described by Prissick and Masson (1956) as the
causative agent of cervical lymph node infections in children. It is scotochromogenic, fails to hydrolyse Tween-80 or reduce nitrate, but is, in
contrast to M. intracellulare, urease positive. The negative result of the
Tween-hydrolysis test distinguishes M. scrofulaceum from the saprophytic
scotochromogens.
M. scrofulaceum has three serotypes with the numbers 41,42 and 43. The
original names of these types were Scrofulaceum, Lunning and Gause
(Schaefer, 1968).
F. Mycobacterium xenopi
M. xenopi was isolated by Schwabacher (1959) from a toad. Its occurrence in human infections was reported by Marks and Schwabacher
(1965). It is very slow growing and forms microcolonies at 37°C. Its
optimal growth temperature range is 4245°C. The colonies are yellow and
give positive results on the three-day arylsulphatase test. I n contrast to
M . intracellulare, M . xenopi is sensitive to Streptomycin, Isoniazid and
Ethionamide (Bretey and Boisvert, 1969).
M . xenopi has been differentiated serologically from other types of mycobacteria in the agar double diffusion (Beck and Stanford, 1968)) and complement fixation tests (Kantor et al., 1970). Differentiation is also possible
by chromatographic analysis of lipids (Jenkins et al., 1972). Whether M.
xenopi can be differentiated from other microcolony forming and nonpigmented mycobacteria is not yet known.
G. Mycobacterium simiae
The name was originally given to a group of atypical poorly growing
photochromogenic mycobacteria isolated from monkeys (Karassova et al.,
1965). Some of these strains were niacin-positive (Weiszfeiler et al., 1971).
Valdivia et al. (1971) reported the isolated of niacin-positive Runyon group
I11 strains resembling mycobacteria from sputa in Cuba and named them
M. habana. Meissner and Schroeder (1975) found the niacin-positive
strains of Weiszfeiler and Valdivia to be culturally and antigenically
identical and designated them as M . simiae type 1. This type differed from
M . intracellulare by giving positive results in the niacin and urease tests by
exhibiting delayed photochromogenicity, and by being specifically agglutinated by M . simiae antisera. M . simiae 1 has been found repeatedly in