ABSTRACT
We simulated the frequency of tuberculosis infection in healthcare workers in order to classify the risk of TB transmission for nine hospitals in Medellín, Colombia. We used a risk assessment approach to estimate the average number of infections in three risk groups of a cohort of 1082 workers exposed to potentially infectious patients over 10- and 20-day periods. The risk level of the hospitals was classified according to TB prevalence: two of the hospitals were ranked as being of very high priority, six as high priority and one as low priority. Consistent results were obtained when the simulation was validated in two hospitals by studying 408 healthcare workers using interferon gamma release assays and tuberculin skin testing. The latent infection prevalence using laboratory tests was 41% [95% confidence interval (CI) 34·3-47·7] and 44% (95% CI 36·4-51·0) in those hospitals, and in the simulation, it was 40·7% (95% CI 32·3-49·0) and 36% (95% CI 27·9-44·0), respectively. Simulation of risk may be useful as a tool to classify local and regional hospitals according to their risk of nosocomial TB transmission, and to facilitate the design of hospital infection control plans.
Subject(s)
Infectious Disease Transmission, Patient-to-Professional , Latent Tuberculosis/epidemiology , Models, Statistical , Personnel, Hospital , Tuberculosis, Pulmonary/epidemiology , Tuberculosis, Pulmonary/transmission , Colombia/epidemiology , Computer Simulation , Hospitals/classification , Humans , Incidence , Interferon-gamma Release Tests , Latent Tuberculosis/diagnosis , Prevalence , Risk Assessment/methods , Tuberculin Test , Tuberculosis, Pulmonary/diagnosisABSTRACT
SETTING: The burden of tuberculosis (TB) disease among household contacts of multidrug-resistant TB (MDR-TB) patients is poorly understood and might represent a target for transmission-interrupting interventions. DESIGN: This retrospective cohort study, conducted in Lima, Peru, from June to September 2008, estimated the incidence of TB disease among household contacts of MDR-TB patients in 358 households. RESULTS: Of 2112 household contacts in 80 households (22% of households), 108 (5%) developed TB disease during the study, giving an incidence rate of 2360 per 100 000 contact follow-up years for each of the first 3 years after exposure. Drug susceptibility tests (DST) were available for 50 diseased contacts, of whom 36 (80%) had MDR-TB. Forty-two pairs of index-contact DSTs were available, among which the contact had an identical or less resistant phenotype than the index case in 27 pairs. Multivariate Cox regression demonstrated that male contacts (hazard ratio [HR] 2.8, P < 0.05), with previous TB disease (HR 20.7, P < 0.001) and with associated (non-human immunodeficiency virus) comorbidities (HR 11.2, P < 0.001) were more likely to develop TB. CONCLUSION: The high percentage of diseased household contacts highlights an opportunity for household-level interventions to prevent transmission, whether or not these cases were all attributable to the index case.
Subject(s)
Antitubercular Agents/therapeutic use , Family Characteristics , Tuberculosis, Multidrug-Resistant/epidemiology , Adolescent , Adult , Cohort Studies , Cost of Illness , Female , Follow-Up Studies , Humans , Incidence , Male , Microbial Sensitivity Tests , Multivariate Analysis , Peru/epidemiology , Proportional Hazards Models , Retrospective Studies , Tuberculosis, Multidrug-Resistant/drug therapy , Young AdultABSTRACT
BACKGROUND: Overcrowded emergency departments (EDs) are used by undiagnosed tuberculosis (TB) patients. TB infection control measures are seldom prioritized, making EDs potential foci of unrecognised nosocomial transmission. OBJECTIVE: To quantify TB infection risk among health care workers in an ED in a high TB-burden setting, Lima, Peru, and to evaluate TB infection control measures. METHODS: Consenting ED staff were tested for TB infection at baseline and after 1 year using the QuantiFERON-TB Gold In-Tube (QFT-G). In parallel, sputum for TB culture was requested from patients spending >2 h in the ED, irrespective of presenting complaint. Infection control measures were documented and room ventilation measured. RESULTS: Over 1 year, there were 2246 TB patient-hours of exposure in the ED from 153 different patients. At baseline, 56% of the 70 staff recruited were QFT-G-positive; 27 of 31 baseline-negatives consented to follow-up after 1 year, and eight (30%, all clinical staff) tested positive. Annual incidence of infection was 1730 per 100,000 population. TB infection control measures were sub-optimal, with no patient screening, no isolation rooms, inadequate ventilation and sporadic respirator use. CONCLUSIONS: ED staff were exposed to an unexpectedly large TB burden in the workplace, resulting in a high rate of TB infection. TB infection control should be prioritized in EDs, especially in high-prevalence settings.
