Effect Of Microbial Colonization Research Articles

Bone loss with aging is independent of gut microbiome in mice

Emerging evidence suggests a significant role of gut microbiome in bone health. Aging is well recognized as a crucial factor influencing the gut microbiome. In this study, we investigated whether age-dependent microbial change contributes to age-related bone loss in CB6F1 mice. The bone phenotype of 24-month-old germ-free (GF) mice was indistinguishable compared to their littermates colonized by fecal transplant at 1-month-old. Moreover, bone loss from 3 to 24-month-old was comparable between GF and specific pathogen-free (SPF) mice. Thus, GF mice were not protected from age-related bone loss. 16S rRNA gene sequencing of fecal samples from 3-month and 24-month-old SPF males indicated an age-dependent microbial shift with an alteration in energy and nutrient metabolism potential. An integrative analysis of 16S predicted metagenome function and LC-MS fecal metabolome revealed an enrichment of protein and amino acid biosynthesis pathways in aged mice. Microbial S-adenosyl methionine metabolism was increased in the aged mice, which has previously been associated with the host aging process. Collectively, aging caused microbial taxonomic and functional alteration in mice. To demonstrate the functional importance of young and old microbiome to bone, we colonized GF mice with fecal microbiome from 3-month or 24-month-old SPF donor mice for 1 and 8 months. The effect of microbial colonization on bone phenotypes was independent of the microbiome donors’ age. In conclusion, our study indicates age-related bone loss occurs independent of gut microbiome.

Healthcare-Associated Infections in Subjects With Severe Acquired Brain Injury: The Effect of Microbial Colonization on the Functional Outcome. Data From a Multicenter Observational Study.

Background: Hospital-acquired infections (HAIs) and microbial colonization are a worldwide serious threat for human health. Neurological patients with infections who undergo rehabilitation have a significantly poor recovery. The effect of microbial colonization on the functional outcome in severe acquired brain injury (sABI) subjects is still unclear.Aim: The aim of this multicenter observational study was to describe the clinical impact of HAIs and colonization on the functional outcome of sABI subjects admitted to inpatient neurorehabilitation.Methods: Patients were assigned to three groups: infected (INF), not infected (noINF), and colonized (COL). The Glasgow Coma Scale (GCS), the Rancho Los Amigos Levels of Cognitive Functioning Scale, Disability Rating Scale, and modified Barthel Index (mBI) assessments were performed both at admission and discharge.Results: Two hundred sixty-five (92 female/173 male) patients were enrolled: 134 were assigned to INF, 63 to COL, and 68 to noINF. In the INF group, 231 culture specimens were found positive for bloodstream (44.2%), respiratory tract (25.5%), urinary tract (18.6%), gastrointestinal tract (8.3%), skin (3%), and cerebrospinal fluid (0.4%) infections. After rehabilitation, all groups showed a significant improvement in all assessment tests, except for the noINF group that did not show any improvement in GCS. Both noINF and COL groups showed a significantly higher gain in mBI than the INF group (p = 0.000). The COL group showed a significantly higher gain than the noINF group in GCS (p = 0.001). A significantly lower improvement was detected in the INF group than the COL and noINF groups. The rate of patients who needed functional isolation was higher in the INF group than the COL group. Length of stay (LOS) (in days) was 56 ± 50.7, 88.3 ± 55, and 101.3 ± 73.6 for noINF, INF, and COL groups, respectively. The number of deaths in the INF group was significantly higher (24.6%) than the noINF group (7.4%) (p = 0.005) and comparable to the COL group (19%).Conclusion: Colonized sABI patients obtained a similar functional outcome to that of subjects who had no infections, even if they needed a significantly higher LOS.

The effect of microbial colonization on the host proteome varies by gastrointestinal location.

Endogenous intestinal microbiota have wide-ranging and largely uncharacterized effects on host physiology. Here, we used reverse-phase liquid chromatography-coupled tandem mass spectrometry to define the mouse intestinal proteome in the stomach, jejunum, ileum, cecum and proximal colon under three colonization states: germ-free (GF), monocolonized with Bacteroides thetaiotaomicron and conventionally raised (CR). Our analysis revealed distinct proteomic abundance profiles along the gastrointestinal (GI) tract. Unsupervised clustering showed that host protein abundance primarily depended on GI location rather than colonization state and specific proteins and functions that defined these locations were identified by random forest classifications. K-means clustering of protein abundance across locations revealed substantial differences in host protein production between CR mice relative to GF and monocolonized mice. Finally, comparison with fecal proteomic data sets suggested that the identities of stool proteins are not biased to any region of the GI tract, but are substantially impacted by the microbiota in the distal colon.

Variation in microbial communities colonizing horticultural slow sand filter beds: implications for filter function

The effect of microbial colonization on the function and rejuvenation of slow sand filters was investigated using culture-independent profiling. Colonization resulted in significant reduction in filter pore size, which may be important in order to fully remove pathogens, but was not associated with a specific microbial component. Communities were highly variable, and no common microbial groups were found in effective filters. Bacterial community composition was affected by sand particle size, although high levels of microbial turnover during filter maturation suggested that this was unlikely to have a major influence on community composition. The composition of microbial inoculum from a previous filter could not be maintained through a cycle of culture, storage and re-culture. Furthermore, no significant proportion of the inoculum persisted in filter maturity, and no advantages in terms of time to filter maturation or final filter efficiency were evident. These results may explain why filtration is such an effective and robust water treatment and emphasize the need for further research on the mechanisms involved in pathogen elimination.