OBJECTIVE: To contribute to measures against hospital-acquired infections by analyzing and evaluating tuberculosis contact investigations in hospitals. METHODS: This study included 202 tuberculosis cases between January 2010 and September 2011 in which contact investigations were requested from the Public Health Office in Osaka City. RESULTS: 1) To assess the necessity for contact investigation and the demographics of index cases, contact investigations were conducted for 66 of the 202 cases. Index cases with higher rates of contact investigation included those with "higher degree of sputum smear positivity," "respiratory symptoms," "period from hospitalization to tuberculosis diagnosis of 8 days or longer," and "high-risk procedures (including endotracheal intubation, endotracheal aspiration, and bronchofiberscopy)." 2) A total of 632 contact persons from the following professions underwent QuantiFERON-TB (QFT) testing: 59 doctors, 492 nurses, 60 other hospital staff members, and 21 patients, and the positive QFT rates were 18.6, 10.8, 13.3, and 14.3%, respectively. 3) Among the 66 index cases for which contact investigations were conducted, there were 0 QFT-positive contact persons in 37 cases (56.1%), 1 or more in 29 (43.9%), and 2 or more in 18 cases (27.3%). Assuming the dependent variable to be 0 and 1, respectively, for index cases with 0 and 2 or more QFT-positive contact persons, we performed a multiple logistic regression analysis with independent variables that included the presence or absence of high-risk procedures, period from hospitalization to diagnosis either within 7 days or 8 or more days, presence or absence of cough and cavity, and the degree of sputum smear positivity (1+/2+/3+). Among these variables, those significantly associated with cases with 1 and 2 or more QFT-positive persons included the "presence of high-risk procedures" and "period from hospitalization to diagnosis of 8 days or longer" (P < 0.05). DISCUSSION: Our results suggest that early diagnosis and appropriate responses during high-risk procedures may be necessary measures to prevent hospital-acquired infections.
OBJECTIVE: To contribute to measures against hospital-acquired infections by analyzing and evaluating tuberculosis contact investigations in hospitals. METHODS: This study included 202 tuberculosis cases between January 2010 and September 2011 in which contact investigations were requested from the Public Health Office in Osaka City. RESULTS: 1) To assess the necessity for contact investigation and the demographics of index cases, contact investigations were conducted for 66 of the 202 cases. Index cases with higher rates of contact investigation included those with "higher degree of sputum smear positivity," "respiratory symptoms," "period from hospitalization to tuberculosis diagnosis of 8 days or longer," and "high-risk procedures (including endotracheal intubation, endotracheal aspiration, and bronchofiberscopy)." 2) A total of 632 contact persons from the following professions underwent QuantiFERON-TB (QFT) testing: 59 doctors, 492 nurses, 60 other hospital staff members, and 21 patients, and the positive QFT rates were 18.6, 10.8, 13.3, and 14.3%, respectively. 3) Among the 66 index cases for which contact investigations were conducted, there were 0 QFT-positive contact persons in 37 cases (56.1%), 1 or more in 29 (43.9%), and 2 or more in 18 cases (27.3%). Assuming the dependent variable to be 0 and 1, respectively, for index cases with 0 and 2 or more QFT-positive contact persons, we performed a multiple logistic regression analysis with independent variables that included the presence or absence of high-risk procedures, period from hospitalization to diagnosis either within 7 days or 8 or more days, presence or absence of cough and cavity, and the degree of sputum smear positivity (1+/2+/3+). Among these variables, those significantly associated with cases with 1 and 2 or more QFT-positive persons included the "presence of high-risk procedures" and "period from hospitalization to diagnosis of 8 days or longer" (P < 0.05). DISCUSSION: Our results suggest that early diagnosis and appropriate responses during high-risk procedures may be necessary measures to prevent hospital-acquired infections.