M. tuberculosis

Pasteurization, the heating of certain fluids, frequentiy milk or dairy products (see Milk and milk products), destroys potentially harmful organisms such as mycobacteria, M. tuberculosis M. bovis or M. avium. Pasteurization, carried out at 62°C for 30 min or at 72°C for 15 s, is not a sterilization procedure. 

The thiophene analog of chloramphenicol (255) has been synthesized,as also have been similar structures. The antibacterial activity of all was much lower than that of the natural antibiotic. The thioamide of 2-thenoic acid has been prepared in a study of potential antitubercular compounds. It did not surpass thioisonico-tinamide in antitubercular activity. The thiosemicarbazones of thio-phenealdehydes and ketones (cf. Section VII,D) show high activity against Mycobacterium tuberculosis, but are very toxic. The thiosemi-carbazone of 4-(2-thienyl)-3-buten-2-one has been reported to be capable of completely inhibiting the in vitro growth of M. tuberculosis even in relatively low concentrations. ... 

Francis et and Snow have isolated from Mycobacterium phlei and M. tuberculosis two series of growth factors for M. johnei, containing the mycobactins P (12) and T (13), respectively. 

Most aiititubercular drag s are bacteriostatic (slow or retard the growth of bacteria) against the M. tuberculosis bacillus. These dm usually act to inhibit bacterial cell wall synthesis, which slows the multiplication rate of the bacteria. Only isoniazid is bactericidal, with rifampin and streptomycin having some bactericidal activity. 

In 1947, L-rhamnose was first recognized by Stacey as a constituent of Pneumococcus Type II specific polysaccharide. This finding was confirmed, in 1952, by Kabat et al. and in 1955 again by Stacey when 2,4- and 2,5-di-O-methyl-L-rhamnose were synthesized and the former was shown to be identical with a di-O-methylrhamnose, obtained by hydrolysis of the methylated polysaccharide. This result indicated a pyranose ring structure for the rhamnose units in the polysaccharide. Announcement of the identification of D-arabinofuranose as a constituent of a polysaccharide from M. tuberculosis aroused considerable interest. The L-enantiomer had been found extensively in polysaccharides, but reports of the natural occurrence of D-arabinose had been comparatively rare. To have available reference compounds for comparison with degradation products of polysaccharides, syntheses of derivatives (particularly methyl ethers) of both d- and L-arabinose were reported in 1947. 

The Constitution of a Specific Somatic Polysaccharide from M. tuberculosis (Human Strain), N. Haworth, P. W. Kent, and M. Stacey, /. Chem. Soc.. (1948) 1211 -1220. 

Otenhoff, T.H., Kale, A.B., VanEmbden, J.D.A., Thole, J.E.R., Kiessling, R. (1988). The recombinant 65-kD heat shock protein of Mycobacterium bovis bacillus calmette guerin/M. tuberculosis is a target molecule for CD4 + cytotoxic T lymphocytes that lyse human monocytes. J. Exp. Med. 168, 1947-1952. 

Stiepton dn was isolated by Waksman in 1944, and its activity against M tuberculosis ensured its use as a primaiy ding in the treatment of tuberculosis. Unfortunately, its ototoxicity and the rapid development of resistance have tended to modify its usefulness, and although it still remains a front-hne dmg against tuberculosis it is usually used in combination with isoniazid and p(4)-aminosalicyhc acid (section 11.5). Streptomycin also shows activity against other types of bacteria,... 

Capreomycin and viomycin show activity against M. tuberculosis and may be regarded as being second-line antituberculosis drugs. 

There has, unfortunately, been a global resurgenee of tuberculosis in recent years. Multiple drug-resistant M tuberculosis (MDRTB) strains have been isolated in which resistance has been aequired to many drugs used in the treatment of this disease. 

Microorganisms surviving M. tuberculosis Bacterial spores HBV and prions as in Creutzfeldt-Jakob disease Bacterial spores Prions Extreme challenge of resistant bacterial spores Prions (insufficient data)... 

Because of the risks of adverse reaction to the vaccine by persons who had already been exposed to the disease a sensitivity test must be carried out prior to immunization with BCG. A Mantoux skin test assesses an individual s sensitivity to a purified protein derivative (PPD) prepared fi om heat-treated antigens (tuberculin) extracted fiom M tuberculosis. A positive test imphes past infection or past, successful immunization Those with strongly positive tests may have active disease and should be referred to a chest clinic. Many people with active TB, especially disseminated TB, however, sero-convert fiom skin test positive to skin test negative. Results of the skin test must therefore be interpreted with care. 

Once infected with M. tuberculosis, a person s lifetime risk of active TB is about 10%, with about half this risk evident during the first 2 years after infection.2,3,6 Young children, the elderly, and immunocompromised patients have greater risks. HIV-infected patients with M. tuberculosis infection are roughly 100 times more likely to develop active TB than normal hosts owing to the lack of normal cellular immunity.3,9... 

M. tuberculosis is transmitted from person to person by coughing or sneezing.2,6,15 This produces small particles known as droplet nuclei that float in the air for long periods of time. Each droplet contains one to three organisms. It is estimated that 30% of individuals with prolonged contact with an infectious TB patient become infected. 

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