Tuberculosis transmission

Cenrers for Disease Control and Prevention. Draft guidelines for preventing the transmission of tuberculosis in health-care facilities, second edition Notice of comment period, federal Register, vol. 58, no. 195 (October 12, 1993), 52809-52854. 

Tuberculosis is on the increase in developed countries such as the USA and UK furthermore, MAI may be associated with AIDS sufferers. Hospital-acquired opportunistic mycobacteria may cause disseminated infection and also lung infections, endocarditis and pericarditis. Transmission of mycobacterial infection by endoscopy is rare, despite a marked increase in the use of flexible fibreoptic endoscopes, but bronchoscopy is probably the greatest hazard for the transmission ofM tuberculosis and other mycobacteria. Thus, biocides used for bronchoscope disinfection must be ehosen carefully to ensure that such transmission does not occur. 

In the United States, tuberculosis disproportionately affects ethnic minorities as compared with whites, reflecting greater ongoing transmission in ethnic minority communities. Additional tuberculosis surveillance and preventive treatment are required within these communities. 

Basu S, Andrews JR, Poolman EM, Gandhi NR, Shah NS, Moll A et al. Prevention of nosocomial transmission of extensively drug-resistant tuberculosis in rural South African district hospitals an epidemiological modelling study. Lancet 2007 370(9597) 1500-7. 

M. tuberculosis (the tubercle bacillus) and other mycobacteria are resistant to many bactericides. Resistance is either (a) intrinsic, mainly due to reduced cellular permeability or (b) acquired, due to mutation or the acquisition of plasmids. Tuberculosis remains an important public health hazard, and indeed the annual number of tuberculosis cases is rising in many countries. The greatest risk of acquiring infection is from the undiagnosed patient. Equipment used for respiratory investigations can become contaminated with mycobacteria if the patient is a carrier of this organism. It is important to be able to disinfect the equipment to a safe level to prevent transmission of infection to other patients (Table 17.2). 

The purpose of the tuberculosis control plan is to prevent the transmission of tuberculosis (TB), which occurs when an individual inhales a droplet that contains Mycohacterium tuberculosis. M. tuberculosis is aerosolized when an infected individual sneezes, speaks, or coughs. Transmission of TB and exposure to TB can be greatly diminished with early identification and isolation of patients at risk, environmental controls, appropriate use of respiratory protection equipment, education of laboratory employees, and when necessary early initiation of therapy. 

Beck-Sague C, Dooley SW, Hutton MD, et al. Hospital outbreak of multidmg-resistant Mycobacterium tuberculosis infections Eactors in transmission to staff and HIV-infected patients. JAMA 1992 268 1280-1286. 

Agent Index A317 Class Index C24 Melioidosis Pseudomonas pseudomalle Type Bacteria Presents a range of manifestations from asymptomatic involvement of the lungs to necrotizing pneumonia and/or fatal blood poisoning. May simulate typhoid fever or tuberculosis. Routes Incubation 2 days to Inhalation years Ingestion Mortality Rate — Abraded Skin Reservoir Soils, Water, Rodents, Secondary Hazards Farm animals Body Fluids Direct Person-to-Person Transmission does not occur. 

Is the immune response to mycobacteria also under the control of the microbial genome Viewed from the perspective of M. tuberculosis, the 10% failure rate associated with natural immunity fully supports transmission of infection and maintenance of a healthy microbial population. Perhaps this represents a window generated by active immune subversion by the pathogen Or, from a more interactive viewpoint, pathogen variants may have been selected to exploit niches associated with variations in the immune response. To parallel the human studies, we can look for evidence of this in the genetic diversity of M. tuberculosis. 

Type Bacteria blood poisoning. May simulate typhoid fever or tuberculosis. Body Fluids Direct Person-to-Person Transmission does not occur. 

Yetman M., Porter S., Ronayne D., Ralph P., Cooze H., Reid U., et al., 2010. Guideline for Preventing the Transmission of Mycobacterium Tuberculosis across the Continuum of Care. 

Airborne transmission refers to infections that are contracted from airborne micro-organisms such as dust, which can transmit spores of Clostridium Difficile or aerosol droplets which can hold tuberculosis or severe acute respiratory syndrome (SARS) (Ulrich and Wilson, 2006). Hospital air quality plays a decisive role in affecting the concentration of pathogens in the air, and thereby has major effects on the frequency of airborne infectious diseases such as tuberculosis, influenza and SARS. When ventilation systems are contaminated or break down, the consequences can be extremely serious. In one outbreak, for example, the ventilation grilles in two patient bays were found to be harbouring MRS A (Kumari et al, 1998). Whenever this ventilation system... 

Guidelines for Preventing Transmission of Mycobacterium tuberculosis in Healthcare Facilities (2005)... 

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