Transmission and Institutional Infection Control of Tuberculosis

Abstract

Tuberculosis (TB) transmission control in institutions is evolving with increased awareness of the rapid impact of treatment on transmission, the importance of the unsuspected, untreated case of transmission, and the advent of rapid molecular diagnostics. With active case finding based on cough surveillance and rapid drug susceptibility testing, in theory, it is possible to be reasonably sure that no patient enters a facility with undiagnosed TB or drug resistance. Droplet nuclei transmission of TB is reviewed with an emphasis on risk factors relevant to control. Among environmental controls, natural ventilation and upper-room ultraviolet germicidal ultraviolet air disinfection are the most cost-effective choices, although high-volume mechanical ventilation can also be used. Room air cleaners are generally not recommended. Maintenance is required for all engineering solutions. Finally, personal protection with fittested respirators is used in many situations where administrative and engineering methods cannot assure protection. HOW TUBERCULOSIS IS TRANSMITTED

Diverse approaches to preventing occupational tuberculosis in health workers: cross-disciplinary or cross purposes?

“…While outbreaks in US hospitals were effectively contained by this package of measures, administrative-level measures, particularly early diagnosis, isolation and treatment of patients with TB, are frequently identified as the most effective of the triad. 10 The difficulty of following these guidelines in low-resource, high TB burden settings was quickly recognised, however, and modified versions were developed by the World Health Organization (WHO) from the 1990s onwards. 5,6 The WHO approach emphasises elements more in keeping with the needs of low-resource countries.…”

“…In the face of the continued generalised epidemic of HIV-related TB and drug-resistant TB characteristic of high TB burden countries, the administrative component of IPC has recently been 'refocused' as a programme in the form of FAST. 10,18 While its three components, i.e., active TB case finding in patients arriving at health facilities, separation to avoid onward infection and effective treatment are clearly not new, the point of departure is that these have not to date been fully implementable or implemented in many health care facilities. What is relatively new is the emergence of the technical capacity for early and rapid diagnosis of TB disease and of drug susceptibility of the organism using GeneExpert technology (Cepheid, Sunnyvale, CA, USA), as also the availability of effective treatment for some forms of drug-resistant TB.…”

“…The advocates of this approach have emphasised its narrowed primary prevention focus by promoting the term 'TB transmission control' rather than 'infection control' more generally and the argument that, 'Unlike hand washing…FAST implementation is not fundamentally an educational campaign for employees… (but) ... requires an investment in resources and specific person-nel…' 10 An operational evaluation of FAST in Bangladesh has indicated successfully increased rates of detection of unsuspected TB and of drug-resistant disease. 19 However, the impact of FAST on reducing TB rates in HCWs is still under study.…”

Where is tuberculosis transmission happening? Insights from the literature, new tools to study transmission and implications for the elimination of tuberculosis

“…One such programme is the ‘Finding TB cases Actively, Separating safely, and Treating effectively (F‐A‐S‐T)’ strategy, which incorporates early case detection, diagnosis and treatment to reduce the risk and duration of exposure for both patients and healthcare workers . Environmental controls, including natural and mechanical ventilation and ultraviolet germicidal irradiation (UVGI), and redesign of healthcare facilities to separate potentially infectious individuals from other patients can also reduce the risk of nosocomial transmission …”

Optical model of the murine lung to optimize pulmonary illumination

“…[12][13][14][15] These external illumination methods allow for longitudinal studies but, unfortunately, suffer from a relatively high detection threshold compared with physiologically relevant infectious doses of 1 to 10 bacteria. 16 A pulmonary bacterial load of 10 5 colony forming units (CFU) or higher is needed to effectively detect the signal. This high detection threshold limits these methods when determining therapeutic efficacy of antimicrobials for pathogenic bacteria.…”