ODELAM Rapid sequence-independent detection of drug resistance in isolates of Mycobacterium tuberculosis
- Seattle Children's Research Institute, United States
- University of Washington, United States
- Vanderbilt University, United States
Abstract
Antimicrobial-resistant Mycobacterium tuberculosis (Mtb) causes over 200,000 deaths each year. Current assays of antimicrobial resistance need knowledge of mutations that confer drug resistance, or long periods of culture time to test growth under drug pressure. We present ODELAM (One-cell Doubling Evaluation of Living Arrays of Mycobacterium), a time-lapse microscopy-based method that observes individual cells growing into microcolonies. ODELAM enables rapid quantitative measures of growth kinetics in as little as 30 hours under a wide variety of environmental conditions. We demonstrate ODELAM's utility by identifying ofloxacin resistance in cultured clinical isolates of Mtb and benchmark its performance with standard minimum inhibitory concentration (MIC) assays. In Mtb isolate, ODELAM identified ofloxacin heteroresistance and identifies the presence of drug resistant colony forming units (CFUs) at 1 per 1000 CFUs in as little as 48 hours. ODELAM is a powerful new tool that can rapidly evaluate Mtb drug resistance in a laboratory setting.
Data availability
MATLAB data *.mat files and MATLAB *.m files utilized for generating figures in this submission are posted at Dryad. Additional source code has been made available at https://github.com/AitchisonLab/
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ODELAM: Rapid sequence-independent detection of drug resistance in clinical isolates of Mycobacterium tuberculosisDryad Digital Repository, doi:10.5061/dryad.b8gtht78q.
Article and author information
Author details
Funding
National Institutes of Health (U19 AI135976)
- David R Sherman
- John D Aitchison
National Institutes of Health (U19 AI111276)
- John D Aitchison
National Institutes of Health (R01 AI141953)
- John D Aitchison
National Institutes of Health (P41 GM109824)
- John D Aitchison
National Institutes of Health (R01 AI063200)
- Timothy R Sterling
National Institutes of Health (R56 AI118361)
- Timothy R Sterling
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Miles P Davenport, University of New South Wales, Australia
Version history
- Received: March 3, 2020
- Accepted: May 12, 2020
- Accepted Manuscript published: May 13, 2020 (version 1)
- Version of Record published: June 1, 2020 (version 2)
Copyright
© 2020, Herricks et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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ODELAM Rapid sequence-independent detection of drug resistance in isolates of Mycobacterium tuberculosis
eLife 9:e56613.
https://doi.org/10.7554/eLife.56613
Further reading
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- Microbiology and Infectious Disease
Antimicrobial resistance (AMR) poses a significant threat to human health. Although vaccines have been developed to combat AMR, it has proven challenging to associate specific vaccine antigens with AMR. Bacterial plasmids play a crucial role in the transmission of AMR. Our recent research has identified a group of bacterial plasmids (specifically, IncHI plasmids) that encode large molecular mass proteins containing bacterial immunoglobulin-like domains. These proteins are found on the external surface of the bacterial cells, such as in the flagella or conjugative pili. In this study, we show that these proteins are antigenic and can protect mice from infection caused by an AMR Salmonella strain harboring one of these plasmids. Furthermore, we successfully generated nanobodies targeting these proteins, that were shown to interfere with the conjugative transfer of IncHI plasmids. Considering that these proteins are also encoded in other groups of plasmids, such as IncA/C and IncP2, targeting them could be a valuable strategy in combating AMR infections caused by bacteria harboring different groups of AMR plasmids. Since the selected antigens are directly linked to AMR itself, the protective effect extends beyond specific microorganisms to include all those carrying the corresponding resistance plasmids.
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- Microbiology and Infectious Disease
Canine distemper virus (CDV) belongs to morbillivirus, including measles virus (MeV) and rinderpest virus, which causes serious immunological and neurological disorders in carnivores, including dogs and rhesus monkeys, as recently reported, but their vaccines are highly effective. The attachment glycoprotein hemagglutinin (CDV-H) at the CDV surface utilizes signaling lymphocyte activation molecule (SLAM) and Nectin-4 (also called poliovirus-receptor-like-4; PVRL4) as entry receptors. Although fusion models have been proposed, the molecular mechanism of morbillivirus fusion entry is poorly understood. Here, we determined the crystal structure of the globular head domain of CDV-H vaccine strain at 3.2 Å resolution, revealing that CDV-H exhibits a highly tilted homodimeric form with a six-bladed β-propeller fold. While the predicted Nectin-4-binding site is well conserved with that of MeV-H, that of SLAM is similar but partially different, which is expected to contribute to host specificity. Five N-linked sugars covered a broad area of the CDV-H surface to expose receptor-binding sites only, supporting the effective production of neutralizing antibodies. These features are common to MeV-H, although the glycosylation sites are completely different. Furthermore, real-time observation using high-speed atomic force microscopy revealed highly mobile features of the CDV-H dimeric head via the connector region. These results suggest that sugar-shielded tilted homodimeric structure and dynamic conformational changes are common characteristics of morbilliviruses and ensure effective fusion entry and vaccination.
