Incremental yield of Xpert® MTB/RIF Ultra over Xpert® MTB/RIF in the diagnosis of extrapulmonary TB.

BACKGROUND: Extrapulmonary TB (EPTB) comprises approximately 15-20% of TB cases worldwide, and its diagnosis is difficult. The sensitivity of Xpert® MTB/RIF (Xpert) in the diagnosis of EPTB is low on account of its paucibacillary nature. Xpert® MTB/RIF Ultra (Ultra) was developed to improve sensitivity.OBJECTIVE: To compare the sensitivity of Ultra test with that of Xpert against MGIT™ (Mycobacteria Growth Indicator Tube) culture and a composite reference standard (CRS).METHODS: We recruited consecutive treatment-naïve patients with suspected EPTB. Demographic information, clinical and relevant laboratory data were collected.RESULTS: From January 2019 to November 2019, 210 patients provided 250 samples. Against MGIT culture, the sensitivity of Ultra was significantly higher than Xpert (72% vs. 51.1%; P = 0.04), the specificity was lower (87.8% vs. 95.1%). Against the CRS also, the sensitivity of Ultra was significantly higher than Xpert (45.4% vs. 25.2%; P = 0.002); however, the specificities were similar (98.2% vs. 99.1%). The trend towards higher sensitivity of Ultra compared to Xpert was seen in most of the individual samples. The sensitivities against MGIT and CRS were as follows: lymph node (68.1% vs. 31.8%; P = 0.01) and (59.5% vs. 23.8%; P = 0.001), pleural biopsy (80.0% on both; P = NS) and (53.8% vs. 46.2%; P = NS) and pleural fluid (66.7% vs. 50%; P = NS) and (22.5% vs. 9.6%; P = NS), respectively.CONCLUSIONS: Xpert Ultra showed a significantly higher sensitivity in diagnosing EPTB than Xpert.

Impact of point-of-care implementation of Xpert® MTB/RIF: product vs. process innovation.

BACKGROUND: Both product innovation (e.g., more sensitive tests) and process innovation (e.g., a point-of-care [POC] testing programme) could improve patient outcomes. OBJECTIVE: To study the respective contributions of product and process innovation in improving patient outcomes. DESIGN: We implemented a POC programme using Xpert(®) MTB/RIF in an out-patient clinic of a tertiary care hospital in India. We measured the impact of process innovation by comparing time to diagnosis with routine testing vs. POC testing. We measured the impact of product innovation by comparing accuracy and time to diagnosis using smear microscopy vs. POC Xpert. RESULTS: We enrolled 1012 patients over a 15-month period. Xpert had high accuracy, but the incremental value of one Xpert over two smears was only 6% (95%CI 3-12). Implementing Xpert as a routine laboratory test did not reduce the time to diagnosis compared to smear-based diagnosis. In contrast, the POC programme reduced the time to diagnosis by 5.5 days (95%CI 4.3-6.7), but required dedicated staff and substantial adaptation of clinic workflow. CONCLUSION: Process innovation by way of a POC Xpert programme had a greater impact on time to diagnosis than the product per se, and can yield important improvements in patient care that are complementary to those achieved by introducing innovative technologies.

Endogenous excess cortisol production and diabetes mellitus as predisposing factors for pulmonary cryptococcosis: a case report and literature review.

Pulmonary cryptococcosis usually occurs as an opportunistic infection in immunocompromised patients. Endogenous Cushing's syndrome is associated with cortisol excess and can predispose to development of cryptococcal infections. We report a case of diabetic patient with ACTH secreting pituitary tumour who developed a cavitating lung mass. Computed tomography-guided biopsy of the lesion revealed mucicarminophilic budding forms of cryptococcus. Broncheoalveolar lavage culture grew Cryptococcus neoformans. There was radiological response to treatment with liposomal Amphotericin, but patient ultimately succumbed to septicemia and multiorgan failure. Opportunistic infections with organisms like Cryptococcus neoformans, should be considered in patients with endogenous Cushing's syndrome and a pulmonary infiltrate.