Quantifying the contribution of smear-negative, culture-positive pulmonary tuberculosis to nosocomial transmission.

BACKGROUND: Despite current guidelines for tuberculosis (TB) control in health care settings, which focused on smear-positive cases, prevention of nosocomial TB transmission continues to be a challenge. Here, we report the results of the first hospital-wide prospective study applying interferon-gamma release assay to investigate the role of smear-negative, culture-positive index cases in nosocomial TB transmission. METHODS: We prospectively identified cases of culture-confirmed smear-negative pulmonary TB receiving aerosol-generating procedures (AGPs) and cases of culture-confirmed smear-positive pulmonary TB admitted at a medical center. Nosocomial transmission was evaluated by screening their close contacts for latent TB infection (LTBI) using an interferon-gamma release assay. RESULTS: A total of 93 smear-negative index receiving AGP and 122 smear-positive index were enrolled. Among them, 13 (14.0%) and 43 (35.2%) index cases, respectively, had secondary cases of LTBI (P < .001). Sputum smear negativity (adjusted odds ratio: 0.20 [0.08-0.48]) and AGP (sputum suction; adjusted odds ratio: 3.48 [1.34-9.05]) are independent factors of transmission. A similar proportion in the close contacts of the 2 index groups had LTBI (17 [15.3%] and 63 [16.0%], respectively), and the former index group contributed to 21.3% of the nosocomial transmission. CONCLUSIONS: Smear-negative, culture-positive index cases receiving AGPs could be as infectious as smear-positive index cases. Hospital TB control policy should also focus on the former group.

Developing a machine-learning model for real-time prediction of successful extubation in mechanically ventilated patients using time-series ventilator-derived parameters.

Background: Successful weaning from mechanical ventilation is important for patients admitted to intensive care units. However, models for predicting real-time weaning outcomes remain inadequate. Therefore, this study aimed to develop a machine-learning model for predicting successful extubation only using time-series ventilator-derived parameters with good accuracy. Methods: Patients with mechanical ventilation admitted to the Yuanlin Christian Hospital in Taiwan between August 2015 and November 2020 were retrospectively included. A dataset with ventilator-derived parameters was obtained before extubation. Recursive feature elimination was applied to select the most important features. Machine-learning models of logistic regression, random forest (RF), and support vector machine were adopted to predict extubation outcomes. In addition, the synthetic minority oversampling technique (SMOTE) was employed to address the data imbalance problem. The area under the receiver operating characteristic (AUC), F1 score, and accuracy, along with the 10-fold cross-validation, were used to evaluate prediction performance. Results: In this study, 233 patients were included, of whom 28 (12.0%) failed extubation. The six ventilatory variables per 180 s dataset had optimal feature importance. RF exhibited better performance than the others, with an AUC value of 0.976 (95% confidence interval [CI], 0.975-0.976), accuracy of 94.0% (95% CI, 93.8-94.3%), and an F1 score of 95.8% (95% CI, 95.7-96.0%). The difference in performance between the RF and the original and SMOTE datasets was small. Conclusion: The RF model demonstrated a good performance in predicting successful extubation in mechanically ventilated patients. This algorithm made a precise real-time extubation outcome prediction for patients at different time points.

Subsequent Antituberculous Treatment May Not Be Mandatory Among Surgically Resected Culture-Negative Pulmonary Granulomas: A Retrospective Nationwide Multicenter Cohort Study.

BACKGROUND: Histologic diagnosis of granuloma is often considered clinically equivalent to a definite diagnosis of pulmonary tuberculosis (TB) in endemic areas. Optimal management of surgically resected granulomatous inflammation in lung with negative mycobacterial culture results, however, remains unclear. METHODS: From 7 medical institutions in northern, middle, and southern Taiwan between January 2010 and December 2018, patients whose surgically resected pulmonary nodule(s) had histological features suggestive of TB but negative microbiological study results and who received no subsequent anti-TB treatment were identified retrospectively. All patients were followed up for 2 years until death or active TB disease was diagnosed. RESULTS: A total of 116 patients were enrolled during the study period. Among them, 61 patients (52.6%) were clinically asymptomatic, and 36 (31.0%) patients were immunocompromised. Solitary pulmonary nodule accounted for 44 (39.6%) of all cases. The lung nodules were removed by wedge resection in 95 (81.9%), lobectomy in 17 (14.7%), and segmentectomy in 4 (3.4%) patients. The most common histological feature was granulomatous inflammation (n=116 [100%]), followed by caseous necrosis (n=39 [33.6%]). During follow-up (218.4 patient-years), none of the patients developed active TB. CONCLUSIONS: In patients with surgically resected culture-negative pulmonary granulomas, the incidence rate of subsequent active TB is low. Watchful monitoring along with regular clinical, radiological, and microbiological follow-up, instead of routine anti-TB treatment, may also be a reasonable option.

Outcome of untreated lung nodules with histological but no microbiological evidence of tuberculosis.

BACKGROUND: The outcome of lung nodule(s) with histopathological findings suggestive of tuberculosis (TB) but lack of microbiologic confirmation remains unclear. Whether these patients require anti-TB treatment remains unknown. The aim of the study was to compare the risk of active TB within 4 years in untreated patients with histological findings but no microbiological evidences suggestive of TB. METHODS: From January 2008 to June 2013, patients with either solitary or multiple lung nodules having histological findings but no microbiological evidences suggestive of TB were identified from a medical center in Taiwan and were followed for 4 years unless they died or developed active TB. RESULTS: A total of 107 patients were identified. Among them, 54 (51%) were clinical asymptomatic. Biopsy histology showed granulomatous inflammation in 106 (99%), and caseous necrosis was present in 55 (51%) cases. Forty (37%) patients received anti-TB treatment, and 21 (53%) of them had adverse events, including 13 initially asymptomatic patients. Anti-TB treatment was favored in patients with caseous necrosis, whereas observation was preferred in subjects whose nodules were surgically removed. Only 1 case in the untreated group developed culture-confirmed active pulmonary TB during 4-year follow-up (1 case per 251.2 patient-years). None of the 16 cases having co-existing histologic finding of malignancy became incident TB case within a follow-up of 56.7 patient-years. CONCLUSIONS: In patients having lung nodules with only histologic features suggestive of TB, the incidence rate of developing active TB was low. Risk of adverse events and benefit from immediate treatment should be carefully considered.

Transthoracic Ultrasound Elastography in Pulmonary Lesions and Diseases.

Ultrasound elastography has shown promising result in the diagnosis of various diseases; however, its application for pulmonary diseases has yet to be clarified. This study aimed to assess the application and feasibility of ultrasound elastography in various pulmonary lesions and diseases. We enrolled 45 patients with radiographic evidence of pneumonia, tumors or obstructive pneumonitis, and 70 ultrasonic lesions were identified (eight necrosis, 17 atelectasis, seven consolidation and 38 tumors). Ultrasound elastography was performed and the strain ratio, which is the ratio of strain of the reference tissue to an equally measuring region of interest of a lesion, was measured. The strain ratio was significantly different among lesions with different ultrasound morphologies (1.03 ± 0.71 [necrosis] vs. 2.51 ± 1.14 [atelectasis] vs. 19.98 ± 15.59 [consolidation] vs. 36.19 ± 20.18 [tumor]; p < 0.05). The strain ratio of primary lung cancer was also significantly different from pneumonia (p = 0.023) and metastatic lung cancer (p = 0.015). In conclusion, transthoracic ultrasound elastography can differentiate pulmonary lesions with different ultrasound morphologies. ClinicalTrials.gov Identifier: NCT02636985.