The World Tuberculosis Day is 24th of March. It’s time to get to know one of the most dangerous diseases, according to the World Health Organization, Tuberculosis (TB). Thanks to science it is a curable disease, with an estimated 53 million lives saved through diagnosis and treatment between 2000 and 2016. Sadly, in 2016, 1.7 million people worldwide still died from the disease.
TB is an infectious disease caused by Mycobacterium tuberculosis that most often affects the lungs. TB is spread from person to person via the air by sneezing, coughing, spitting or even speaking.
To avoid becoming seriously ill with TB, there are some things that you can or may already do. The BCG (Bacillus Calmette-Guerin) vaccine has been shown to provide children with excellent protection against the disseminated forms of TB. The BCG vaccination is rarely given to anyone over the age of 16 – and never over the age of 35, because it doesn’t work very well in adults.
You should not be the same area, breathing the same air as a TB-infected person for long periods of time. Always wash your hands thoroughly, keep in mind that good hygienic practice is one of the most important ways avoid diseases.
Environmental mycobacteria, also known as Non Tubercule Mycobacteria (NTM) and mycobacteria other than tuberculosis (MOTT) are widely distributed in the environment, particularly in wet soil, marshland, streams, rivers and estuaries. They belong to the same family as the organisms that cause tuberculosis and leprosy, but unlike those organisms, NTM vary greatly in their ability to cause disease, and are not spread from person to person.
Mycobacterial infections are notoriously difficult to treat due to the organism’s cell wall, which is neither truly Gram negative nor positive. All Mycobacterium species share a characteristic cell wall, thicker than in many other bacteria, which is hydrophobic, waxy, and rich in mycolic acids/mycolates. The cell wall makes a substantial contribution to the hardiness of these organisms enabling them to survive long exposure to acids, alkalis, detergents, oxidative bursts, lysis, heat and many antibiotics.
Environmental mycobacteria also have extraordinary starvation survival persisting despite low nutrient levels in tap water. Furthermore, tolerance of temperature extremes results in contamination of hot tap water, spas, and ice machines by environmental mycobacteria.
Environmental Mycobacteria Testing
Due to their extreme resistance to thermal and chemical disinfection, environmental mycobacteria present a particular problem when they occur in final rinse water used to decontaminate medical devices. Standards and guidance, such as ISO 15883, HTM 2030 (withdrawn), HTM 01-06 (formerly CFPP 01-06) detail the requirements to analyse water samples for the presence of Environmental Mycobacteria. Prior to the release of CFPP 01-06 the requirement was for annual testing. The requirement for Environmental Mycobacteria testing of Endoscopy Final Rinse Water is now quarterly. In accordance with these standards, no Environmental Mycobacteria should be detected in the final rinse water after 28 days incubation. These organisms present in final rinse water can cause issues as some species are opportunistic pathogens, but also can create false-positive results in biopsies.
Normal growth media will not support the growth of Environmental Mycobacteria, so a specific, supplemented growth agar is used to promote the organisms growth. Samples are incubated at 30°C for 28 days, but are checked every 7 days for presumptive growth. Presumptive colonies are confirmed as Environmental Mycobacteria by negative oxidase reaction and Ziehl-Neelsen staining.
A Medical Device Alert (MDA/2015/022) released in 2015 linked the presence of Environmental Mycobacteria (M.chimaera) in the water of cardiac heater coolers to infections post-operative, and has results in guidance being released for the testing of water and air from these machines.
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