Tables
- TABLE 1
Air changes per hour (ACH) and removal efficiencies of Mycobacterium tuberculosis droplets
ACH Time required for removal efficiency min 99% 99.9% 2 138 207 4 69 104 6 46 69 12 23 35 20 14 21 Reproduced and modified from [4].
- TABLE 2
Comparison of guidelines on selected preventive measures for protection against Mycobacterium tuberculosis in hospitals separated by topics
Guidelines/recommendations WHO [6, 7] USA [4, 12, 24, 26] UK [5, 8, 25] Germany [3, 9, 13, 23] Spatial requirements NPI rooms Yes Yes Yes Yes Normal ventilation room allowed Yes Yes, if air-cleaning technologies (e.g. a portable HEPA filtration system) are available Yes, single rooms that are vented to the outside of the building Yes, single rooms that are vented to the outside of the building Frequency of air exchange in NPI rooms Minimum 12 per h Prefer ≥12 per h (minimum ≥6 per h) “Adequate ventilation” Optionally 12 per h Frequency of air exchange in normal ventilation rooms Not addressed Minimum 2 per h Not addressed Not addressed Personal protection Minimum standard of masks N95 or FFP2 N95 or FFP2 FFP2 FFP2 Masks when encountering MDR-TB patients FFP3 not addressed >N95 FFP3 FFP3 Masks during aerosol-generating procedures FFP2 >N95 FFP2 [5], FFP3 [8] FFP2 [3] or at least FFP 2 [23] Removal from isolation Sputum smear-positive patients Discussed, but no recommendation provided Minimum 2-week treatment, progressively decreasing M. tuberculosis load, then 3 microscopy-negative sputum smear-results Only after at least 2-week treatment, and given a low initial smear (grade 2 or less), then 3 negative sputum smear results After 3-week treatment [23] or after 3-week treatment and 3 microscopy-negative sputum smear results [3], in each case dependent on clinical and radiographic improvement Sputum smear-negative patients Not addressed After two negative results of the Xpert MTB/RIF test No isolation After 3 microscopy- negative sputum results, depending on further medical consideration [3] or after 3-week treatment and clinical and radiographic improvement [23] MDR-TB patients Not addressed (isolation only for culture-positive XDR-TB patients) After at least 1 negative culture After 3 microscopy-negative smears at weekly intervals and ideally 1 negative culture After 3 microscopy-negative smears, possibly after 1 negative culture [3] or definitely after 1 negative culture [23] Screening for LTBI Serial testing of healthcare workers Not addressed At the discretion of healthcare facilities; routine serial testing not recommended Not addressed (BCG vaccination instead?) Yes, required by law (Ordinance of Occupational Health Care) in risk-prone healthcare facilities Disinfection Upper-air or in-duct UV disinfection (UVGI) Yes Yes, but not in lieu of ventilation Not addressed Noted as general option, but not recommended WHO: World Health Organization; NPI: negative pressure isolation; HEPA: high efficiency particulate air; FFP: filtering face piece; MDR: multidrug-resistant; XDR: extensively drug-resistant; TB: tuberculosis; RIF: rifampicin; XDR: extensively drug resistant; LTBI: latent TB infection; BCG: bacille Calmette–Guérin; UVGI: ultraviolet germicidal irradiation.
Vol 6 Issue 1
Table of Contents
Protection of healthcare workers against transmission of Mycobacterium tuberculosis in hospitals: a review of the evidence
