EasyNAT MTC assay: A simple, rapid, and low-cost cross-priming amplification method for the detection of mycobacterium tuberculosis suitable for point-of-care testing.

More sensitive, rapid, and affordable diagnostic tools for pulmonary tuberculosis (PTB) are urgently needed. This study aimed to assess the performance of EasyNAT MTC (abbreviation: EasyNAT) (Ustar Biotechnologies, China), a novel isothermal amplification method with a turnaround time of less than two hours that requires a few manual steps to process the sputum. Sputum samples from 249 patients with suspected PTB were subjected to smear, culture, Xpert MTB/RIF (Cepheid, USA) and EasyNAT assay testing. Of the 169 PTB patients, EasyNAT detected more PTB patients than Xpert (72.19% vs. 61.54%, P < 0.05, χ2 = 4.326). Both the Xpert assay and EasyNAT assay detected almost all the culture-positive sputa successfully, but EasyNAT yielded more positive results among the smear-negative and culture-negative PTB cases (44.59% (33/74) vs. 22.97% (17/74), P < 0.01, χ2 = 7.732). Although the specificity of EasyNAT was lower in contrast to Xpert [95.00% (76/80) vs. 98.75% (79/80)], the difference was not significant (P = 0.363, χ2 = 0.826). EasyNAT could be used as an initial test for PTB diagnosis due to its simplicity, rapid turnaround time, high sensitivity, and low cost.

Carbonyl Cyanide 3-Chlorophenylhydrazone (CCCP) Exhibits Direct Antibacterial Activity Against Mycobacterium abscessus.

OBJECTIVE: Treatment choices for Mycobacterium abscessus (M. abscessus) infections are very limited, and the prognosis is generally poor. Effective new antibiotics or repurposing existing antibiotics against M. abscessus infection are urgently needed. Carbonyl cyanide 3-chlorophenylhydrazone (CCCP), a member of the lipophilic weak acid class, is known as an efflux pump inhibitor for Mycobacterium tuberculosis. The aim of this study was to determine the inhibitory activity of CCCP as a potential novel antibiotic against M. abscessus. METHODS: A total of 47 reference strains of different mycobacterial species and 60 clinical isolates of M. abscessus were enrolled. In vitro inhibitory activity of CCCP was accessed using microplates alamar blue method with the reference and clinical isolates. The activity of CCCP against intracellular M. abscessus residing within macrophage was also evaluated by intracellular colony numerating assay. RESULTS: CCCP exhibited good activity against M. abscessus clinical isolates in vitro, the minimum inhibitory concentration (MIC) ranged from 0.47 µg/mL to 3.75 µg/mL, with a MIC50 of 1.875 µg/mL and MIC90 of 3.75 µg/mL. At concentrations safe for the cells, CCCP exhibited highly intracellular bactericidal activities against M. abscessus and M. massiliense reference strains, with inhibitory rates of 84.8%±8.8% and 72.5%±13.7%, respectively. CCCP demonstrated bactericidal activity against intracellular M. abscessus that was comparable to clarithromycin, and concentration-dependent antimicrobial activity against M. abscessus in macrophages was observed. In addition, CCCP also exhibited good activities against most reference strains of rapidly growing mycobacterial species. CONCLUSION: CCCP could be a potential candidate of novel antimicrobiological agent to treat M. abscessus infection.