Spatial and Temporal Shifts in Bacterial Biogeography and Gland Occupation during the Development of a Chronic Infection

ABSTRACT Gland colonization may be one crucial route for bacteria to maintain chronic gastrointestinal infection. We developed a quantitative gland isolation method to allow robust bacterial population analysis and applied it to the gastric pathobiont Helicobacter pylori. After infections in the mur...

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Autores principales:	Daniela Keilberg, Yana Zavros, Benjamin Shepherd, Nina R. Salama, Karen M. Ottemann
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2016
Materias:	Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/367ac532772e4d7faa03cb36fa6b4867
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spelling	oai:doaj.org-article:367ac532772e4d7faa03cb36fa6b48672021-11-15T15:50:14ZSpatial and Temporal Shifts in Bacterial Biogeography and Gland Occupation during the Development of a Chronic Infection10.1128/mBio.01705-162150-7511https://doaj.org/article/367ac532772e4d7faa03cb36fa6b48672016-11-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.01705-16https://doaj.org/toc/2150-7511ABSTRACT Gland colonization may be one crucial route for bacteria to maintain chronic gastrointestinal infection. We developed a quantitative gland isolation method to allow robust bacterial population analysis and applied it to the gastric pathobiont Helicobacter pylori. After infections in the murine model system, H. pylori populations multiply both inside and outside glands in a manner that requires the bacteria to be motile and chemotactic. H. pylori is able to achieve gland densities averaging 25 to 40 bacteria/gland after 2 to 4 weeks of infection. After 2 to 4 weeks of infection, a primary infection leads to colonization resistance for a secondary infection. Nonetheless, about ~50% of the glands remained unoccupied, suggesting there are as-yet unappreciated parameters that prevent gastric gland colonization. During chronic infections, H. pylori populations collapsed to nearly exclusive gland localization, to an average of <8 bacteria/gland, and only 10% of glands occupied. We analyzed an H. pylori chemotaxis mutant (Che−) to gain mechanistic insight into gland colonization. Che− strains had a severe inability to spread to new glands and did not protect from a secondary infection but nonetheless achieved a chronic gland colonization state numerically similar to that of the wild type. Overall, our analysis shows that bacteria undergo substantial population dynamics on the route to chronic colonization, that bacterial gland populations are maintained at a low level during chronic infection, and that established gland populations inhibit subsequent colonization. Understanding the parameters that promote chronic colonization will allow the future successful design of beneficial microbial therapeutics that are able to maintain long-term mammalian colonization. IMPORTANCE Many bacteria have an impressive ability to stay in the gastrointestinal tract for decades despite ongoing flow and antimicrobial attacks. How this staying power is achieved is not fully understood, but it is important to understand as scientists plan so-called designer microbiomes. The gastrointestinal tract is lined with repeated invaginations called glands, which may provide one niche for chronic colonization. We developed a quantitative gland isolation method to allow robust and efficient bacterial population analysis and applied it to the gastric pathogen Helicobacter pylori. Bacterial populations increased inside and outside glands at early time points but were found exclusively within glands during late time points in the chronic state. H. pylori required the ability to swim to move to new glands. Last, a fit gland bacterial population leads to colonization resistance of a second one. Our approach identified previously unappreciated aspects of gland occupation, supporting the idea that glands are the desired niche for stable, chronic colonization.Daniela KeilbergYana ZavrosBenjamin ShepherdNina R. SalamaKaren M. OttemannAmerican Society for MicrobiologyarticleMicrobiologyQR1-502ENmBio, Vol 7, Iss 5 (2016)
institution	DOAJ
collection	DOAJ
language	EN
topic	Microbiology QR1-502
spellingShingle	Microbiology QR1-502 Daniela Keilberg Yana Zavros Benjamin Shepherd Nina R. Salama Karen M. Ottemann Spatial and Temporal Shifts in Bacterial Biogeography and Gland Occupation during the Development of a Chronic Infection
description	ABSTRACT Gland colonization may be one crucial route for bacteria to maintain chronic gastrointestinal infection. We developed a quantitative gland isolation method to allow robust bacterial population analysis and applied it to the gastric pathobiont Helicobacter pylori. After infections in the murine model system, H. pylori populations multiply both inside and outside glands in a manner that requires the bacteria to be motile and chemotactic. H. pylori is able to achieve gland densities averaging 25 to 40 bacteria/gland after 2 to 4 weeks of infection. After 2 to 4 weeks of infection, a primary infection leads to colonization resistance for a secondary infection. Nonetheless, about ~50% of the glands remained unoccupied, suggesting there are as-yet unappreciated parameters that prevent gastric gland colonization. During chronic infections, H. pylori populations collapsed to nearly exclusive gland localization, to an average of <8 bacteria/gland, and only 10% of glands occupied. We analyzed an H. pylori chemotaxis mutant (Che−) to gain mechanistic insight into gland colonization. Che− strains had a severe inability to spread to new glands and did not protect from a secondary infection but nonetheless achieved a chronic gland colonization state numerically similar to that of the wild type. Overall, our analysis shows that bacteria undergo substantial population dynamics on the route to chronic colonization, that bacterial gland populations are maintained at a low level during chronic infection, and that established gland populations inhibit subsequent colonization. Understanding the parameters that promote chronic colonization will allow the future successful design of beneficial microbial therapeutics that are able to maintain long-term mammalian colonization. IMPORTANCE Many bacteria have an impressive ability to stay in the gastrointestinal tract for decades despite ongoing flow and antimicrobial attacks. How this staying power is achieved is not fully understood, but it is important to understand as scientists plan so-called designer microbiomes. The gastrointestinal tract is lined with repeated invaginations called glands, which may provide one niche for chronic colonization. We developed a quantitative gland isolation method to allow robust and efficient bacterial population analysis and applied it to the gastric pathogen Helicobacter pylori. Bacterial populations increased inside and outside glands at early time points but were found exclusively within glands during late time points in the chronic state. H. pylori required the ability to swim to move to new glands. Last, a fit gland bacterial population leads to colonization resistance of a second one. Our approach identified previously unappreciated aspects of gland occupation, supporting the idea that glands are the desired niche for stable, chronic colonization.
format	article
author	Daniela Keilberg Yana Zavros Benjamin Shepherd Nina R. Salama Karen M. Ottemann
author_facet	Daniela Keilberg Yana Zavros Benjamin Shepherd Nina R. Salama Karen M. Ottemann
author_sort	Daniela Keilberg
title	Spatial and Temporal Shifts in Bacterial Biogeography and Gland Occupation during the Development of a Chronic Infection
title_short	Spatial and Temporal Shifts in Bacterial Biogeography and Gland Occupation during the Development of a Chronic Infection
title_full	Spatial and Temporal Shifts in Bacterial Biogeography and Gland Occupation during the Development of a Chronic Infection
title_fullStr	Spatial and Temporal Shifts in Bacterial Biogeography and Gland Occupation during the Development of a Chronic Infection
title_full_unstemmed	Spatial and Temporal Shifts in Bacterial Biogeography and Gland Occupation during the Development of a Chronic Infection
title_sort	spatial and temporal shifts in bacterial biogeography and gland occupation during the development of a chronic infection
publisher	American Society for Microbiology
publishDate	2016
url	https://doaj.org/article/367ac532772e4d7faa03cb36fa6b4867
work_keys_str_mv	AT danielakeilberg spatialandtemporalshiftsinbacterialbiogeographyandglandoccupationduringthedevelopmentofachronicinfection AT yanazavros spatialandtemporalshiftsinbacterialbiogeographyandglandoccupationduringthedevelopmentofachronicinfection AT benjaminshepherd spatialandtemporalshiftsinbacterialbiogeographyandglandoccupationduringthedevelopmentofachronicinfection AT ninarsalama spatialandtemporalshiftsinbacterialbiogeographyandglandoccupationduringthedevelopmentofachronicinfection AT karenmottemann spatialandtemporalshiftsinbacterialbiogeographyandglandoccupationduringthedevelopmentofachronicinfection
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Spatial and Temporal Shifts in Bacterial Biogeography and Gland Occupation during the Development of a Chronic Infection

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