Mycobacterium simiae and related mycobacteria

Area of Science:

• Microbiology
• Mycobacteriology
• Primate Health

Background:

• Mycobacterial infections in non-human primates can pose zoonotic risks.
• Tuberculin-negative monkeys may harbor atypical mycobacteria.
• Characterization of novel mycobacterial species is crucial for disease control.

Purpose of the Study:

• To isolate and identify mycobacterial strains from imported monkeys.
• To determine the drug susceptibility and virulence of isolated species.
• To investigate the antigenic properties and serotypes of the identified mycobacteria.

Main Methods:

• Isolation and identification of mycobacteria from monkey samples.
• Antitubercular drug susceptibility testing.
• Virulence studies in white mice.
• Gel precipitation method for antigen analysis.
• Serotyping of Mycobacterium simiae strains.

Main Results:

• Fifty mycobacterial strains were isolated; 14 identified as Mycobacterium simiae and 4 as Mycobacterium asiaticum.
• Both species are slow-growing, niacin-positive (M. simiae), photochromogenic, virulent in mice, and contagious.
• Drug resistance to streptomycin, isoniazid, p-aminosalicylate, and rifampin was observed, with sensitivity to cycloserine.
• Gel precipitation revealed shared antigens with Mycobacterium tuberculosis, with Mycobacterium species strain 52 being distinct.
• Mycobacterium simiae strains belonged to two serotypes, with Mycobacterium habana classified under serotype 1.

Conclusions:

• Mycobacterium simiae and Mycobacterium asiaticum are significant isolates from imported monkeys, exhibiting distinct drug resistance and virulence profiles.
• The contagious nature and potential for intrauterine transmission highlight the importance of monitoring these mycobacteria in primate populations.
• Antigenic analysis reveals cross-reactivity with Mycobacterium tuberculosis, necessitating careful diagnostic considerations.