Bacteroides thetaiotaomicron: a dynamic, niche‐adapted human symbiont

Comstock, Laurie E.; Coyne, Michael J.

doi:10.1002/bies.10350

Cited by 96 publications

(61 citation statements)

References 17 publications

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“…This idea would imply that sialylation may be required for persistence and that, if so, a therapeutic approach blocking surface modification could have broad clinical value by causing certain microbes to become sensitive to host clearance mechanisms. Evidence that surface carbohydrate modification plays a role in symbiosis comes from Bacteroides spp., in which the synthesis of eight structurally distinct capsular polysaccharides varies randomly in response to a site-specific recombinase for reversible inversion of the different capsule biosynthetic operon promoters (12). In contrast, our results point to the variation at the level of LOS sialylation being dependent on a supply of host sialic acid.…”

Section: Discussioncontrasting

confidence: 53%

Sialic Acid Metabolism and Systemic Pasteurellosis

et al. 2005

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Pasteurella multocida subsp. multocida is a commensal and opportunistic pathogen of food animals, wildlife, and pets and a zoonotic cause of human infection arising from contacts with these animals. Here, an investigation of multiple serotype A strains demonstrated the occurrence of membrane sialyltransferase. Although P. multocida lacks the genes for the two earliest steps in de novo sialic acid synthesis, adding sialic acid to the growth medium resulted in uptake, activation, and subsequent transfer of sialic acid to a membrane acceptor resembling lipooligosaccharide. Two candidate-activating enzymes with homology to Escherichia coli cytidine 5-monophospho-N-acetylneuraminate synthetase were overproduced as histidine-tagged polypeptides. The synthetase encoded by pm0187 was at least 37 times more active than the pm1710 gene product, suggesting pm0187 encodes the primary sialic acid cytidylyltransferase in P. multocida. A sialate aldolase (pm1715) mutant unable to initiate dissimilation of internalized sialic acid was not attenuated in the CD-1 mouse model of systemic pasteurellosis, indicating that the nutritional function of sialate catabolism is not required for systemic disease. In contrast, the attenuation of a sialate uptake-deficient mutant supports the essential role in pathogenesis of a sialylation mechanism that is dependent on an environmental (host) supply of sialic acid. The combined results provide the first direct evidence of sialylation by a precursor scavenging mechanism in pasteurellae and of a potential tripartite ATP-independent periplasmic sialate transporter in any species.

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Section: Discussioncontrasting

confidence: 53%

Sialic Acid Metabolism and Systemic Pasteurellosis

et al. 2005

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“…In some cases the factor may regulate large numbers of prokaryotic genes, and in some cases the genes comprising a sigma factor regulon have a clearly defined function (131). One class of these factors, the extracytoplasmic function -factors, known as ECF-type -factors, are relatively small proteins (65). They are frequently associated with specific membrane-tethered cognates, known as anti--factors.…”

Section: Environmental Sensing Systemsmentioning

confidence: 99%

Bacteroides: the Good, the Bad, and the Nitty-Gritty

2007

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SUMMARY Summary: Bacteroides species are significant clinical pathogens and are found in most anaerobic infections, with an associated mortality of more than 19%. The bacteria maintain a complex and generally beneficial relationship with the host when retained in the gut, but when they escape this environment they can cause significant pathology, including bacteremia and abscess formation in multiple body sites. Genomic and proteomic analyses have vastly added to our understanding of the manner in which Bacteroides species adapt to, and thrive in, the human gut. A few examples are (i) complex systems to sense and adapt to nutrient availability, (ii) multiple pump systems to expel toxic substances, and (iii) the ability to influence the host immune system so that it controls other (competing) pathogens. B. fragilis, which accounts for only 0.5% of the human colonic flora, is the most commonly isolated anaerobic pathogen due, in part, to its potent virulence factors. Species of the genus Bacteroides have the most antibiotic resistance mechanisms and the highest resistance rates of all anaerobic pathogens. Clinically, Bacteroides species have exhibited increasing resistance to many antibiotics, including cefoxitin, clindamycin, metronidazole, carbapenems, and fluoroquinolones (e.g., gatifloxacin, levofloxacin, and moxifloxacin).

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“…*P Ͼ 0.005. The genus Bacteroides makes up a substantial portion of Bacteroidetes in the gastrointestinal tract, and the species B. thetaiotaomicron is a well-characterized Bacteroides member found in both the human and mouse intestine (7,10,15,35,40,58,91). Based on the increased luminal [Na ϩ ], we sought to determine whether B. thetaiotaomicron was responsible for the increase in luminal Bacteroides in the NHE3 Ϫ/Ϫ terminal ileum.…”

Section: Nhe3mentioning

confidence: 99%

Loss of NHE3 alters gut microbiota composition and influencesBacteroides thetaiotaomicrongrowth

Engevik

Aihara

Montrose

et al. 2013

American Journal of Physiology-Gastrointestinal and Liver Physi

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Changes in the intestinal microbiota have been linked to diabetes, obesity, inflammatory bowel disease, and Clostridium difficile ( C. difficile)-associated disease. Despite this, it remains unclear how the intestinal environment, set by ion transport, affects luminal and mucosa-associated bacterial composition. Na+/H+-exchanger isoform 3 (NHE3), a target of C. difficile toxin B, plays an integral role in intestinal Na+ absorption. Thus the NHE3-deficient mouse model was chosen to examine the effect of pH and ion composition on bacterial growth. We hypothesized that ion transport-induced change in the intestinal environment would lead to alteration of the microbiota. Region-specific changes in ion composition and pH correlated with region-specific alteration of luminal and mucosal-associated bacteria with general decreases in Firmicutes and increases in Bacteroidetes members. Bacteroides thetaiotaomicron ( B. thetaiotaomicron) increased in NHE3−/− terminal ileum and was examined in vitro to determine whether altered Na+ was sufficient to affect growth. Increased in vitro growth of B. thetaiotaomicron occurred in 43 mM Na+ correlating with the NHE3−/− mouse terminal ileum [Na+]. NHE3−/− terminal ileum displayed increased fut2 mRNA and fucosylation correlating with B. thetaiotaomicron growth. Inoculation of B. thetaiotaomicron in wild-type and NHE3−/− terminal ileum organoids displayed increased fut2 and fucosylation, indicating that B. thetaiotaomicron alone is sufficient for the increased fucosylation seen in vivo. These data demonstrate that loss of NHE3 alters the intestinal environment, leading to region-specific changes in bacteria, and shed light on the growth requirements of some gut microbiota members, which is vital for creating better treatments of complex diseases with an altered gut microbiota.

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Bacteroides thetaiotaomicron: a dynamic, niche‐adapted human symbiont

Cited by 96 publications

References 17 publications

Sialic Acid Metabolism and Systemic Pasteurellosis

Sialic Acid Metabolism and Systemic Pasteurellosis

Bacteroides: the Good, the Bad, and the Nitty-Gritty

Loss of NHE3 alters gut microbiota composition and influencesBacteroides thetaiotaomicrongrowth

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