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Aggregation of Nontuberculous Mycobacteria in Vitro and in Situ

DePas, W. and Bergkessel, M. and Newman, D. K. (2017) Aggregation of Nontuberculous Mycobacteria in Vitro and in Situ. In: 31st Annual North American Cystic Fibrosis Conference, 2-4 November 2017, Indianapolis, IN.

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The incidence of nontuberculous mycobacterial (NTM) infections in cystic fibrosis (CF) patients is increasing, with some CF clinics in the US reporting NTM prevalence upwards of 25%. In addition, the current treatment regimen for NTM involves long courses of antibiotic cocktails that demonstrate limited efficacy and cause frequent and serious side effects. Mycobacterium abscessus, in particular, is difficult to treat and correlates with a more rapid decline in lung function compared to Mycobacterium avium complex. Studies with zebrafish and human cell cultures have demonstrated that M. abscessus is more virulent when aggregated into cord-like biofilms, in part because of the decreased ability of phagocytes to efficiently engulf and kill corded M. abscessus compared to diffuse M. abscessus cells. Translating these findings into useful clinical strategies for treating NTM infections will be greatly aided by 1.) A thorough understanding of the environmental conditions and genetic networks that control NTM aggregation, and 2.) Information about the in vivo aggregation state of NTM during infection. To address item 1, we developed an in vitro aggregation assay in which NTM such as M. abscessus and the model strain Mycobacterium smegmatis aggregate and disperse regularly in liquid culture. We found that M. smegmatis aggregation was dependent on carbon source type and availability. In particular, glycerol catabolism induces aggregation while pyruvate or amino acid catabolism leads to growth as dispersed cells. In contrast, oxygen availability does not induce changes in aggregation state. Currently, we are performing experiments in order to elucidate the genetic regulators that trigger aggregation in response to glycerol catabolism.

Item Type:Conference or Workshop Item (Poster)
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URLURL TypeDescription
Bergkessel, M.0000-0002-4530-1224
Newman, D. K.0000-0003-1647-1918
Additional Information:© 2017 Wiley Periodicals, Inc. Issue online: 19 September 2017; Version of record online: 19 September 2017.
Group:Division of Geological and Planetary Sciences
Issue or Number:S47
Record Number:CaltechAUTHORS:20171012-103413414
Persistent URL:
Official Citation:(2017), Poster Session Abstracts. Pediatr Pulmonol., 52: S214–S516. doi:10.1002/ppul.23840
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:82309
Deposited By: Tony Diaz
Deposited On:12 Oct 2017 22:19
Last Modified:27 Apr 2023 00:00

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