Influence of Sampling Site and other Environmental Factors on the Bacterial Community Composition of Domestic Washing Machines

Modern, mainly sustainability-driven trends, such as low-temperature washing or bleach-free liquid detergents, facilitate microbial survival of the laundry processes. Favourable growth conditions like humidity, warmth and sufficient nutrients also contribute to microbial colonization of washing machines. Such colonization might lead to negatively perceived staining, corrosion of washing machine parts and surfaces, as well as machine and laundry malodour. In this study, we characterized the bacterial community of 13 domestic washing machines at four different sampling sites (detergent drawer, door seal, sump and fibres collected from the washing solution) using 16S rRNA gene pyrosequencing and statistically analysed associations with environmental and user-dependent factors. Across 50 investigated samples, the bacterial community turned out to be significantly site-dependent with the highest alpha diversity found inside the detergent drawer, followed by sump, textile fibres isolated from the washing solution, and door seal. Surprisingly, out of all other investigated factors only the monthly number of wash cycles at temperatures ≥ 60 °C showed a significant influence on the community structure. A higher number of hot wash cycles per month increased microbial diversity, especially inside the detergent drawer. Potential reasons and the hygienic relevance of this finding need to be assessed in future studies.

Fruit Consumption is Associated with Alterations in Microbial Composition and Lower Rates of Pouchitis

Background Patients with ulcerative colitis [UC] who undergo proctocolectomy with an ileal pouch–anal anastomosis commonly develop pouch inflammation [pouchitis]. Pouchitis develops in a previously normal small intestine and may involve environmental factors. We explored whether diet and microbiota alterations contributed to the pathogenesis of pouchitis. Methods Patients were recruited and prospectively followed at a comprehensive pouch clinic. Pouch behaviour was clinically defined as a normal pouch [NP] or pouchitis. Patients completed Food Frequency Questionnaires [FFQs]. Faecal samples were analysed for microbial composition [16S rRNA gene pyrosequencing]. Results Nutritional evaluation was performed in 172 patients [59% females], and of these, faecal microbial analysis was performed in 75 patients (microbiota cohort: NP [n = 22], pouchitis [n = 53]). Of the entire cohort, a subgroup of 39 [22.6%] patients had NP at recruitment [NP cohort]. Of these, 5 [12.8%] developed pouchitis within a year. Patients at the lowest tertile of fruit consumption [<1.45 servings/day] had higher rates of pouchitis compared with those with higher consumption [30.8% vs 3.8%, log rank, p = 0.03]. Fruit consumption was correlated with microbial diversity [r = 0.35, p = 0.002] and with the abundance of several microbial genera, including Faecalibacterium [r = 0.29, p = 0.01], Lachnospira [r = 0.38, p = 0.001], and a previously uncharacterized genus from the Ruminococcaceae family [r = 0.25, p = 0.05]. Reduction in fruit consumption over time was associated with disease recurrence and with reduced microbial diversity [Δ = –0.8 ± 0.3, p = 0.008]. Conclusions Fruit consumption is associated with modification of microbial composition, and lower consumption was correlated with the development of pouchitis. Thus, fruit consumption may protect against intestinal inflammation via alteration of microbial composition.

Characterization of Microbiota in Bronchiectasis Patients with Different Disease Severities

The application of 16S rRNA gene pyrosequencing has expanded our knowledge about the respiratory tract microbiome originally obtained using conventional, culture-based methods. In this study, we employed DNA-based molecular techniques for examining the sputum microbiome in bronchiectasis patients in relation to disease severity. Of 63 study subjects, 42 had mild and 21 had moderate or severe bronchiectasis, which was classified by calculating the FACED score based on FEV1 (forced expiratory volume in 1 s, %) (F, 0&ndash;2 points), age (A, 0&ndash;2 points), chronic colonization by Pseudomonas aeruginosa (C, 0-1 point), radiographic extension (E, 0&ndash;1 point), and dyspnoea (D, 0&ndash;1 point). Bronchiectasis was defined as mild at 0&ndash;2 points, moderate at 3&ndash;4 points, and severe at 5&ndash;7 points. The mean age was 68.0 &plusmn; 9.3 years; 33 patients were women. Haemophilus (p=0.005) and Rothia (p=0.043) were significantly more abundant in the mild bronchiectasis group, whereas Pseudomonas (p=0.031) was significantly more abundant in the moderate or severe group. However, the alpha or beta diversity did not significantly differ among sputum microbiota, i.e. the same dominating genera were found in all samples. Further large-scale studies are needed to investigate the sputum microbiome in bronchiectasis.

Bacteria in tropical floodplain soils are sensitive to changes in saltwater

Bacterial communities in floodplain and wetland soils cycle elements essential for flora and fauna. The coastal habitats of northern Australia are threatened with increasing saltwater intrusion (SWI) events that will destroy freshwater habitats. The effect of the impending SWI on bacterial communities is unknown. Here, we examined the bacterial communities of a tropical river floodplain located in World Heritage Kakadu National Park. Using 16S rRNA gene pyrosequencing, we measured the baseline bacterial communities from three morphologically distinct regions of the floodplain (lower, upper and backwater swamp), within three zones of the South Alligator River (upstream, cuspate and estuarine funnel or sinuous). Significant differences in the bacterial community were observed at each category of floodplain morphology and river zone. The greatest differences were due to pH and salinity. Large changes in bacterial compositions are predicted to occur with increases in salinity and pH. Saltwater intrusion is predicted to increase substantially in the next decades with sea-level rise, and is likely to cause large and significant changes to the bacterial community with unknown consequences for biogeochemical cycling. Kakadu National Park may benefit from incorporating bacteria into routine studies, because we have shown here that they are sensitive indicators of change, even across small ranges of abiotic variables.

Impact of a probiotic, inulin, or their combination on the piglets’ microbiota at different intestinal locations

Natural feed additives are used to maintain health and to promote performance of pigs without antibiotics. Effects of a probiotic, inulin, and their combination (synbiotic), on the microbial diversity and composition at different intestinal locations were analysed using denaturing gradient gel electrophoresis (DGGE), real-time PCR, and 16S rRNA gene pyrosequencing. Bacterial diversity assessed by DGGE and/or pyrosequencing was increased by inulin in all three gut locations and by the synbiotic in the caecum and colon. In contrast, the probiotic did only affect the microbiota diversity in the ileum. Shifts in the DGGE microbiota profiles of the caecum and colon were detected for the pro- and synbiotic fed animals, whereas inulin profiles were more similar to the ones of the control. 16S rRNA gene pyrosequencing revealed that all three additives could reduce Escherichia species in each gut location, indicating a potential beneficial effect on the gut microbiota. An increase of relative abundance of Clostridiaceae in the large intestine was found in the inulin group and of Enterococcaceae in the ileum of probiotic fed pigs. Furthermore, real-time PCR results showed that the probiotic and synbiotic increased bifidobacterial numbers in the ileum, which was supported by sequencing results. The probiotic and inulin, to different extents, changed the diversity, relative abundance of phylotypes, and community profiles of the porcine microbiota. However, alterations of the bacterial community were not uniformly between gut locations, demonstrating that functionality of feed additives is site specific. Therefore, gut sampling from various locations is crucial when investigations aim to identify the composition of a healthy gut microbiota after its manipulation through feed additives.