Diagnosis of TB disease is confirmed by culturing M. On average, it takes about 2 weeks to culture and identify M. A preliminary diagnosis of TB can be made when acid-fast bacilli are seen by microscope on sputum smear or in other body tissues or fluids. However, microscopy cannot distinguish between M. This is particularly problematic in countries such as the United States where TB incidence is low. Nucleic acid amplification tests are more rapid than culture and specific for M. They are also more sensitive than the acid-fast bacillus smear but less sensitive than culture.
A diagnosis of TB disease can be made by using clinical criteria in the absence of microbiologic confirmation. However, laboratory testing should be performed when feasible to confirm the diagnosis. Molecular tests for drug resistance can be performed directly on specimens and can guide initial treatment while culture results are pending. Culture-based susceptibility testing is recommended for all patients with a positive culture, regardless of the availability of molecular testing, to make a final determination on the appropriate drug regimen.
Tuberculosis is a nationally notifiable disease. For people who have been exposed to isoniazid-resistant, rifampin-susceptible TB or who cannot tolerate isoniazid, 4 months of rifampin is a reasonable alternative. Travelers who suspect that they have been exposed to TB should inform their health care provider of the possible exposure and receive medical evaluation. Because drug resistance is relatively common in some parts of the world, travelers who have TST or IGRA conversion associated with international travel should consult experts in infectious diseases or pulmonary medicine.
TB disease is treated with a multiple-drug regimen administered by directly observed therapy for 6—9 months usually isoniazid, rifampin, ethambutol, and pyrazinamide for 2 months, followed by isoniazid and rifampin for an additional 4 months if the TB is not MDR TB.
Travelers should avoid exposure to TB patients in crowded and enclosed environments such as health care facilities, correctional facilities, or homeless shelters. Travelers who will be working in hospitals or health care settings where TB patients are likely to be encountered should be advised to consult infection control or occupational health experts about procedures for obtaining personal respiratory protective devices such as N respirators , along with respirator selection and training.
BCG may offer some protection in this circumstance; however, people who receive BCG vaccination must follow all recommended TB infection control precautions to the extent possible. To prevent infections due to M.
CDC website: www. CDC Yellow Book. Infectious Agent. Map Estimated tuberculosis incidence rates 1. Table The remaining 65 interviews were not assessable, for the same reasons as listed above for direct observation. Median daily interaction duration as perceived by the HCWs was Agreement was good, although variability was greater for long than for short interactions. Calibration and signal reconstruction allowed us to obtain data on interaction duration, as confirmed by the comparison with direct observation data during the validation phase.
Physicians and medical students were exposed as frequently but for longer times, compared to nurses and nursing assistants.
Diseases and Conditions
Most data on interactions between HCWs and patients are obtained via direct observation by trained observers. Direct observation data may be biased, however, chiefly via the Hawthorne effect. The Hawthorne effect is a change in the behavior of people who know they are being observed. Although not systematically evaluated, several studies in the field of hand hygiene suggested overestimation of compliance related to the Hawthorne effect  , .
Other biases are observer bias, with observers from the audited unit tending to report higher compliance; and selection bias, with direct observation being performed in units or during periods believed to be characterized by better compliance . In addition, direct observation is time-consuming. However, the World Health Organization considered direct observation to be the reference standard for assessing hand-hygiene compliance rates.
Social network specialists and infection control specialists recently developed automatic systems for collecting interactions between HCWs and patients. These systems have proved helpful for assessing contact patterns and studying the spread of respiratory viruses, with the goal of setting up prevention strategies  ,  , .
Also, compliance with hand hygiene at room entry and exit can be measured using electronic devices . Electronic methods allow continuous and automatic collection of person-to-person interactions in hospitals . For our study, we selected tuberculosis because of its epidemiological simplicity, with a single reservoir and exclusive airborne transmission. Moreover, much remains to be learned about the transmission of M. We had some concern that the HCWs might perceive the sensors as intrusive.
However, the study was well accepted, with a high participation rate.
WHO | Tuberculosis and air travel, third edition
We were therefore able to describe interactions between HCWs and patients in two large clinical units. However, we encountered unexpected difficulties in calibrating and reconstructing interactions. Obstacles to the collection of accurate data included technical issues and problems related to real-life conditions e. These technical aspects have been reported previously . Our experience shows that investigators who intend to implement an electronic system for describing social interactions should consider potential obstacles and plan a detailed calibration phase.
Interactions during the morning shift 7 a. In addition, interaction duration was significantly longer during the morning shift. This distribution is in accordance with the organization of care in the wards. The median duration of each interaction was only 2. This is not surprising, as TB patients are usually self-sufficient and do not require major nursing procedures.
However, daily care duration was as long as several hours in some TB patients, suggesting a risk of TB transmission to HCWs in the absence of airborne isolation precautions. However, most HCWs had short interaction durations. These data should prove helpful for investigations by occupational physicians working on risks to HCWs.
The interaction duration cutoff above which a contact investigation should be considered after exposure to an infectious TB patient in the absence of airborne isolation precautions varies widely across recommendations, from 1 hour in France to 8 hours for aircraft passengers in close contact with the case . Our results in two hospital wards show that prolonged contact is rare.
Our finding of longer interactions between TB patients and medical students and residents, compared to HCWs in other job categories, indicates a need for including students and residents into contact investigations. Medical students may not be under monitoring by the hospital occupational physicians and may therefore fail to receive active surveillance after exposure. The good correlation between direct observation data and RFID data confirmed the accuracy of the recorded interactions.
HCW perceptions of daily interaction durations were accurate during interviews conducted after 1 to 7 days. However, some correlations between RFID data and data from either direct observation or interviews were weaker, especially for long interactions, suggesting that signal reconstruction may not always be accurate presence of false-positive and false-negative signals despite signal reconstruction.
Technological improvements will be available soon, such as ultra-wideband radio signals, and will improve indoor sensor network localization. To our knowledge, only one study evaluated interactions between HCWs and patients in a pediatric clinical ward. The authors obtained a high participation rate from HCWs, as in our study. Although not validated by direct observations, the results were essentially similar to our data, with a short median duration of each interaction between participants and large variations of the number and duration of contacts between participants and within job categories .
In conclusion, this preliminary study demonstrates that interactions between HCWs and patients can be recorded accurately and continuously using a RFID. Electronic sensors can be used as an alternative or as a complement to time-consuming short-term direct observation. RFIDs hold promise for better describing exposure and risk, provided correct calibration is performed before data acquisition and appropriate signal reconstruction methods are used. RFIDs could be used for assessing the risk of transmissible infectious diseases.
Browse Subject Areas? Click through the PLOS taxonomy to find articles in your field. Abstract Background Direct observation has been widely used to assess interactions between healthcare workers HCWs and patients but is time-consuming and feasible only over short periods. Methods We equipped 50 patient rooms with fixed sensors and HCW volunteers with mobile sensors in two clinical wards of two hospitals.
Results After signal reconstruction, interactions were recorded between 82 HCWs and 54 tuberculosis patients during days of airborne isolation. Download: PPT.
Figure 1. Flow-chart of healthcare workers participating in the study. Methods Study Design This was an observational, prospective, study in two centers. Table 1. Characteristics of the 82 participating healthcare workers and 54 study patients.