Anaerobic Medium Research Articles

Vagococcus jeotgali sp. nov., isolated from cutlassfish jeotgal, a traditional Korean fermented seafood.

A novel, Gram-positive, facultatively anaerobic, and non-motile bacterial strain, designated B2T-5T, was isolated from jeotgal, a traditional Korean fermented seafood. Colonies grown on gifu anaerobic medium agar plates were cream-coloured, irregular, and umbonate with curled margins. Optimal growth of strain B2T-5T occurred at 20 °C, pH 8.0, and in the presence of 1% (w/v) NaCl. Strain B2T-5T was negative for oxidase and catalase activity. Hippurate was not hydrolysed and acetoin was not produced. The major cellular fatty acids were C18 : 1 ω9c and C16 : 0. The cell-wall peptidoglycan was of the A4α type containing l-Lys-d-Asp. The predominant respiratory quinone was menaquinone 7. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylcholine. According to the phylogenetic analysis based on 16S rRNA gene sequences, strain B2T-5T was most closely related to Vagococcus teuberi DSM 21459T, showing 98.2% sequence similarity. Genome sequencing of strain B2T-5T revealed a genome size of 2.0 Mbp and a G+C content of 33.8 mol%. The average nucleotide identities of strain B2T-5T with Vagococcus teuberi DSM 21459T, Vagococcus bubulae SS1994T, and Vagococcus martis D7T301T were 75.0, 74.7, and 75.1%, respectively. Based on the phenotypic, chemotaxonomic, and genotypic data, strain B2T-5T represents a novel species of the genus Vagococcus, for which the name Vagococcus jeotgali sp. nov. is proposed. The type strain is B2T-5T (=KCTC 21223T=JCM 35937T).

Light-driven extracellular electron transfer accelerates microbiologically influenced corrosion by Rhodopseudomonas palustris TIE-1

This study investigates the microbiologically influenced corrosion (MIC) of X80 steel accelerated by the phototrophic bacterium Rhodopseudomonas palustris TIE-1. The photorespiration plays a key role in promoting extracellular electron transfer (EET)-induced MIC. In the early corrosion stage, unstable localized corrosion dominated in the dark, while intense diffusion-controlled corrosion occurs in light. Compared to the sterile anaerobic medium, R. palustris TIE-1 accelerated corrosion of X80 steel, with a significantly higher corrosion rate under light conditions, approximately three times that of dark conditions. Inhibition of photosynthetic electron transfer or cessation of photostimulation resulted in pronounced reduction in the corrosion rate.

Does hydrogen peroxide help mitigate the incidence of Cutibacterium acnes in cervical spine surgeries?

Background: Surgical site infection (SSI) is a common yet serious complication of cervical spine surgery. While initially thought to be clinically insignificant, Cutibacterium acnes (C. acnes) is an important cause of infection. The purpose of this study was to investigate the ability of an hydrogen peroxide (H2O2) application during standard pre-surgical skin preparation to reduce the burden of C. acnes in patients undergoing cervical spine surgery. Methods: This was a retrospective review of prospectively collected data. Subjects were randomly assigned to either standard surgical preparation plus H2O2 (experimental) or without H2O2 (control). Pre-scrub, post-scrub, and dermal cultures were obtained to assess the C. acnes burden after cultures on an aerobic and anaerobic growth medium were held for 21 days. Multivariate analysis was conducted to determine factors associated with presence of C. acnes. Outcome measures included the results of intraoperative cultures and the development of a SSI within 90 days post-operatively. Results: Patients (n=86) undergoing elective two- or three-level fusion via anterior approach were included. Prior to application of the antiseptic solution, 65% (28/43) of the experimental cohort and 77% (33/43) of the control cohort had positive C. acnes cultures (p=0.34). Following application of antiseptic solution, there were no differences in positive C. acnes culture rates between the experimental and control cohorts in the epidermal (30% versus 28%, p=1.00) or dermal (40% versus 42%, p=1.00) cultures. No differences in the rates of C. acnes eradication from pre-antiseptic to post-antiseptic application occurred for epidermal (p= 1.00) or dermal (p= 1.00) skin layers. None of the factors were associated with positive C. acnes epidermal cultures on multivariable logistic regression analysis (p> 0.05). Conclusions: While there is potential for H2O2 to reduce the positive culture rate of C. acnes in cervical spine patients, no difference was seen when compared to standard surgical skin preparation.

Eubacterium album sp. nov., a butyrate-producing bacterium isolated from faeces of a healthy human.

An oval to rod-shaped, Gram-stain-positive, strictly anaerobic bacterium, designated LFL-14T, was isolated from the faeces of a healthy Chinese woman. Cells of the strain were non-spore-forming, grew optimally at 37 °C (growth range 30-45 °C) and pH 7.0 (growth range 6.0-9.0) under anaerobic conditions in the liquid modified Gifu anaerobic medium (mGAM). The result of 16S rRNA gene-based analysis indicated that LFL-14T shared an identity of 94.7 0% with Eubacterium ventriosum ATCC 27560T, indicating LFL-14T represented a novel taxon. The results of genome-based analysis revealed that the average nucleotide identity (ANI), the digital DNA-DNA hybridisation (dDDH) and average amino acid identity (AAI) between LFL-14T and its phylogenetically closest neighbour, Eubacterium ventriosum ATCC 27560T, were 77.0 %, 24.6 and 70.9 %, respectively, indicating that LFL-14T represents a novel species of the genus Eubacterium. The genome size of LFL-14T was 2.92 Mbp and the DNA G+C content was 33.14 mol%. We analysed the distribution of the genome of LFL-14T in cohorts of healthy individuals, type 2 diabetes patients (T2D) and patients with non-alcoholic fatty liver disease (NAFLD). We found that its abundance was higher in the T2D cohort, but it had a low average abundance of less than 0.2 % in all three cohorts. The percentages of frequency of occurrence in the T2D, healthy and NAFLD cohorts were 48.87 %, 16.72 % and 13.10 % respectively. The major cellular fatty acids of LFL-14T were C16 : 0 (34.4 %), C17 : 0 2-OH (21.4 %) and C14 : 0 (11.7 %). Additionally, the strain contained diphosphatidylglycerol (DPG) and phosphatidylethanolamine (PE), as well as unidentified phospholipids and unidentified glycolipids. The glucose fermentation products of LFL-14T were acetate and butyrate. In summary, On the basis of its chemotaxonomic, phenotypic, phylogenetic and phylogenomic properties, strain LFL-14T (= CGMCC 1.18005T = KCTC 25580T) is identified as representing a novel species of the genus Eubacterium, for which the name Eubacterium album sp. nov. is proposed.

Bentonite as an arsenic and lead adsorbent in the bovine digestive tract: an in vitro study

Objective. To determine the recommended dose of bentonite as a chelator of arsenic (As) and lead (Pb) in the rumen, abomasal and duodenal environment by means of an in vitro system, considering the variables of ruminal fermentation and the adsorbent effect of As and Pb. Materials and Methods. Vials were prepared with 50 mL of anaerobic medium and 0.5 g of alfalfa as substrate. The culture media were added with 1.01 and 1.95 ppm of As and Pb, respectively. The treatments consisted of different levels of bentonite (B) added to the medium, B-0%, B-1.5%, B-3.0% and B-4.5%. The media were incubated for 24 h, and pH, volatile fatty acid (VFA) and N-NH3 production, in vitro DM digestibility (IVDMD) and chelating effect of bentonite were measured, simulating rumen, abomasum and duodenum conditions. A completely randomised design and orthogonal contrasts were used. Results. Bentonite did not modify the pH (p > 0.05) and the molar proportion of VFAs, but the total VFA concentration presented a negative linear effect with increasing bentonite levels. Likewise, the N-NH3 level decreased (p < 0.05) with increasing inclusion levels of bentonite. The IVDMD was reduced with B-3% and B-4.5% (52.36b and 49.74b%) in comparison to B-0% and B-1.5% (62.30a and 61.98a%). Treatments B-1.5% and B-4.5% improved (p < 0.05) As and Pb adsorption in the rumen, abomasal and duodenal environments. Conclusions. The recommended level of bentonite as chelator of As and Pb is 1.5%; doses of 4.5% affect IVDMD and, consequently, animal productivity.

Uses of Microorganisms in The Recovery of Oil and Gas

Microscopic organisms are the only single-celled organisms proposed for the advancement of techniques for Estimation of Oil Recovery (EOR) because they have numerous desirable properties, including a simple structure and an unsustainable growth rate when supplied with vital nutrients, resulting in the release of metabolic chemicals like Aerosols, acids, minimum lubricants, surfactants, and polymers. Clostridium acetobutylicum was isolated from intensive rice cultivation soil and has the ability to use polysaccharides such as starch and carboxylmethyl cellulose to produce biobutanol, while Desulfovibrio hydrocarbonoclasticus was isolated from marine sediment in Iraq and grows in anaerobic synthetic seawater medium with the addition of a trace element solution. These bacteria can also withstand difficult conditions High salinity, high pressure, and high temperature play roles and contribute to underground geological formations. An aqueous mixture of nutrients, Clostridium acetobutylicum, Desulfovibrio hydrocarbonoclasticus, and molasses with nutrient and bacterial spore injection into a reservoir. As a result, these microorganisms are capable of considerable catalytic reactions. production of a diverse spectrum of products (biosolvents, bioacids, biogases, and biosurfactants) from relatively simple nutritional compounds, multiply vigorously under favourable conditions, and have resulted in increased oil release from reservoir rock. The well began producing 70 days after the medication was started. 80 to 90 days after the injection began, relatively brief polyunsaturated fats, Carbon dioxide, and residues of ethanol, 1-butanol, and acetone were detected. Because of their highly resistant endospores, Clostridium are the most ideal of the several microbes used in MEOR (Microbial enhanced oil recovery). Desulfovibrio strains capable of producing biosurfactants in situ, which are beneficial to the MEOR process, are also valuable. Nutrients are often supplied as fermentable carbs to promote microbial metabolism.

Identification of metabolites produced by six gut commensal Bacteroidales strains using non-targeted LC-MS/MS metabolite profiling

As the most abundant gram-negative bacterial order in the gastrointestinal tract, Bacteroidales bacteria have been extensively studied for their contribution to various aspects of gut health. These bacteria are renowned for their involvement in immunomodulation and their remarkable capacity to break down complex carbohydrates and fibers. However, the human gut microbiota is known to produce many metabolites that ultimately mediate important microbe-host and microbe-microbe interactions. To gain further insights into the metabolites produced by the gut commensal strains of this order, we examined the metabolite composition of their bacterial cell cultures in the stationary phase. Based on their abundance in the gastrointestinal tract and their relevance in health and disease, we selected a total of six bacterial strains from the relevant genera Bacteroides, Phocaeicola, Parabacteroides, and Segatella. We grew these strains in modified Gifu anaerobic medium (mGAM) supplemented with mucin, which resembles the gut microbiota’s natural environment. Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based metabolite profiling revealed 179 annotated metabolites that had significantly differential abundances between the studied bacterial strains and the control growth medium. Most of them belonged to classes such as amino acids and derivatives, organic acids, and nucleot(s)ides. Of particular interest, Segatella copri DSM 18205 (previously referred to as Prevotella copri) produced substantial quantities of the bioactive metabolites phenylethylamine, tyramine, tryptamine, and ornithine. Parabacteroides merdae CL03T12C32 stood out due to its ability to produce cadaverine, histamine, acetylputrescine, and deoxycarnitine. In addition, we found that strains of the genera Bacteroides, Phocaeicola, and Parabacteroides accumulated considerable amounts of proline-hydroxyproline, a collagen-derived bioactive dipeptide. Collectively, these findings offer a more detailed comprehension of the metabolic potential of these Bacteroidales strains, contributing to a better understanding of their role within the human gut microbiome in health and disease.

Construction of a versatile in vitro cultivation screening platform using human oral microbiota.

We developed a simulation model of human oral microbiota using Bio Palette oral medium (BPOM) containing 0.02% glucose and lower bacterial nitrogen sources, derived from saliva and dental plaque. By decreasing the concentration of Gifu anaerobic medium (GAM) from 30 to 10 g L-1 , we observed increased ratios of target pathogenic genera, Porphyromonas and Fusobacterium from 0.5% and 1.7% to 1.2% and 3.5%, respectively, in the biofilm on hydroxyapatite (HA) discs. BPOM exhibited the higher ratios of Porphyromonas and Fusobacterium, and amplicon sequence variant number on HA, compared with GAM, modified GAM and basal medium mucin. Mixing glycerol stocks of BPOM culture solutions from four human subjects resulted in comparable ratios of these bacteria to the original saliva. In this simulation model, sitafloxacin showed higher inhibitory effects on P. gingivalis than minocycline hydrochloride at a low dosage of 0.1 μg mL-1 . Probiotics such as Streptococcus salivarius and Limosilactobacillus fermentum also showed significant decreases in Porphyromonas and Fusobacterium ratios on HA, respectively. Overall, the study suggests that BPOM with low carbon and nutrients could be a versatile platform for assessing the efficacy of antibiotics and live biotherapeutics in treating oral diseases caused by Porphyromonas and Fusobacterium.

Caproicibacterium argilliputei sp. nov., a novel caproic acid producing anaerobic bacterium isolated from pit clay.

An anaerobic, Gram-positive, rod-shaped, motile and spore-forming bacterium, designated strain ZCY20-5T, was isolated from pit clay of Chinese strong-aroma type Baijiu (Chinese liquor). Phylogenetic analyses based on 16S rRNA gene and genome sequences showed that strain ZCY20-5T belonged to the genus Caproicibacterium, family Oscillospiracheae, but it showed low similarity to the type species Caproicibacterium amylolyticum LBM18003T (98.00 %) and Caproicibacterium lactatifermentans LBM19010T (95.67 %). In anaerobic yeast extract medium, growth was observed at 20-45 °C (optimum, 35-40 °C), at pH 4.0-9.0 (optimum, pH 6.5-7.0) and with 0.0-2.0 % NaCl (w/v). The predominant fatty acids were C16 : 0, C14 : 0, C13 3-OH and C16 3-OH, and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, three phospholipids of unknown structure containing glucosamine and two unidentified phospholipids. Strain ZCY20-5T exhibited an 81.32 % pairwise average nucleotide identity value, a 78.98 % average amino acid identity value and a 22.30 % digital DNA-DNA hybridization value compared to its closest relative C. amylolyticum LBM18003T. Based on morphological, physiological, biochemical, chemotaxonomic, genotypic and phylogenetic results, strain ZCY20-5T represents a novel species of Caproicibacterium, and the type strain is ZCY20-5T (=MCCC 1A19399T=KCTC 25590T).

The improvement of immunity and activation of TLR2/NF-κB signaling pathway by Romboutsia ilealis in broilers.

This study was conducted to investigate the effects of Romboutsia ilealis on the immune function of broilers and the underlying mechanisms. A total of 48 one-day-old Arbor Acres broilers were allocated to 4 groups as follows: broilers treated daily with 1mL live R. ilealis in general anaerobic medium broth media (0, 1 × 104, 1 × 106, and 1 × 108 CFU/mL) from days 1 to 7. Samples were collected on days 8 and 14. The results showed that R. ilealis had no negative effect on the body weight of broilers (P > 0.05). R. ilealis significantly increased the levels of lysozyme, IFN-γ, IFN-γ/IL-4, and IgG in the serum (P < 0.05). R. ilealis significantly increased the levels of IL-4, IFN-γ, sIgA, lysozyme, and iNOS in the ileal mucosa (P < 0.05). R. ilealis significantly increased the mRNA levels of TLR2, TLR4, NF-κB, IL-1β, TNF-α, IFN-γ, IgA, pIgR, iNOS, and MHC-II in the ileum (P < 0.05). R. ilealis significantly increased the relative abundance of Enterococcus and Paracoccus in the jejunum and ileum, ileal Candidatus Arthromitus, and cecal Romboutsia and Intestinimonas (P < 0.05). Correlation analysis showed that Enterococcus, Paracoccus, Romboutsia, and Intestinimonas were significantly positively correlated with humoral immune function (P < 0.05). In conclusion, R. ilealis boosted the immune system, activated the intestinal TLR2/NF-κB signaling pathway, and improved the gut microbiota in broilers.

An outbreak after all: Cutibacterium acnes among pediatric patients with cerebrospinal fluid diversion device infections highlights gaps in guidelines.

Cutibacterium acnes is normal skin flora but can cause sterile implant infections. We investigated a cluster of seven patients with C. acnes in anaerobic cerebrospinal fluid (CSF) cultures in November 2020. Further analysis identified a missed outbreak, highlighting ambiguity in diagnosis of indolent organisms in the 2017 IDSA meningitis guidelines. Outbreak investigation. Quaternary pediatric facility. A case was defined as a hospitalized patient with C. acnes isolated from CSF culture from January 1, 2016 to December 31, 2022. We defined comparison periods based on timing of C. acnes culture positivity as 1) pre-outbreak (2016-2020), 2) outbreak (2020-2021), and 3) post-outbreak (2022). Rates of C. acnes positive cultures per 1000 CSF cultures and rate ratios were calculated by comparison periods. We identified 9 positive C. acnes CSF cultures among 7 cases November 10-27, 2020, all with at least 1 CSF diversion device. The anaerobic culture media was substituted at the time of case cluster. In 2021, the culture media was implemented permanently with no increase in C. acnes culture positivity. The rate of C. acnes positive CSF cultures and rate ratio increased in the outbreak period (p=0.01) compared to pre-outbreak and post-outbreak periods. There was no difference between the pre- and post-outbreak periods. Retrospective analysis of CSF culture data led to reclassifying a C. acnes pseudo-outbreak as a true outbreak in CSF diversion devices at our institution. Clearer guidance is needed to delineate the role of C. acnes in CSF diversion device infections.

A search for bacteria identified from cerebrospinal fluid shunt infections in previous surgical events.

Shunt infections are a common complication when treating hydrocephalus by cerebrospinal fluid (CSF) shunt placement. The source of infecting pathogens is not well understood. One hypothesis, which we explored here, is that microorganisms persist chronically in the host long before a symptomatic infection occurs and may be detectable in surgical events preceding infection. A cohort of 13 patients was selected, for which CSF samples were available from an infection episode and from a previous surgery event, which was either an initial shunt placement or a revision. Microbiota were analyzed both directly from CSF and from isolates cultured from CSF on aerobic and anaerobic media. The detection and identification of bacteria was done with high throughput DNA sequencing methods and mass spectrometry. The presence of bacteria was confirmed in 4 infection samples, of which 2 were after initial placement and 2 after revision surgery. Taxonomic identification was consistent with clinical microbiology laboratory results. Bacteria were not detected in any of the CSF samples collected at the time of the previous surgical events. While our findings do not provide direct evidence for long-term persistence of pathogens, they suggest the need for consideration of additional source material, such as biofilm and environmental swabs, and/or the use of more sensitive and specific analytical methods.

Diurnal variation of salivary anaerobes correlates severe dental caries in children

Salivary secretion has diurnal fluctuations and the saliva amount affects oral bacterial activity. In this study, the time dependence of number of anaerobic bacteria in saliva such as Streptococcus mutans (S. mutans) was investigated and examined its impact on caries severity. This study was conducted at university hospital in Japan. Twenty subjects (2–10 years old) with the primary dentition were asked to collect whole saliva every 1 hour after the supper while awake at home. Eighteen subjects delivered the collected saliva, which was cultured for S. mutans and total anaerobes in trypticase-yeast extract-cysteine sucrose-bacitracin (TYCSB) medium and the Gifu anaerobic medium (GAM), respectively. The numbers of severe dental caries were also analyzed from medical records. A positive correlation was found between the number of colonies in GAM medium and the saliva collection time of the day. No significant correlation was observed between the number of colonies in TYCSB medium and the collection time. The patients were grouped based on whether or not they had experienced pulp treatment. The number of colonies of S. mutans and anaerobic bacteria were increased in the later hours of only the experienced group. The number of oral anaerobic bacteria of children fluctuated in time-dependent manner after dinner to bedtime, and was higher late in the night. Children with severe dental caries had increased S. mutans as the night progressed, whereas children without them did not.

Performance evaluation of 4-day versus 5-day blood cultures using the BD BACTEC FX system

Background: Blood culture (BC) systems have evolved to increase sensitivity and reduce turnaround times. This study compared the performance of a 4-day versus a 5-day BC incubation period using the BD BACTEC™ FX (Becton, Dickinson and Company, USA). Methods: A total of 37,379 consecutive sets of BC were evaluated over a 3-month period in a 2,700-bed tertiary care hospital. Positive BC results were reviewed to assess time-to-positivity (TTP) and species identification of the isolates. The BCs were performed in pairs of vials, utilizing either BD BACTEC Plus Aerobic/F or Peds Plus/F with BD BACTEC Lytic Anaerobic media. Results: A total of 14,899 episodes, averaging 2.51 sets per episode, were analyzed. Of these, 1,398 (9.38%) were positive, yielding 1,465 isolates. TTP (hours) were &lt; 12 in 48.87%, 12-24 in 31.40%, 24-48 in 13.38%, 48-72 in 3.28%, 72-96 in 1.43%, and &gt;96 in 1.64%. The two most prevalent organisms, Escherichia coli and Klebsiella spp. were detected within 12 hours in 88.75% and 78.90%, respectively. The respective median TTP (T50) values for E. coli, Klebsiella spp., Enterococcus faecalis/E. faecium, and Staphylococcus aureus were 9.24, 9.60, 13.75, and 14.20. T50 values for these species were significantly shorter in anaerobic bottles than in aerobic bottles. Of 24 BCs with TTP &gt; 96, only 4 containing anaerobic bacteria or molds were f irst detected after 96 hours. Conclusion: A 4-day incubation has demonstrated excellent sensitivity. However, a 5-day incubation may be beneficial for hospitals caring for patients at high risk for infections with slow-growing fungi or fastidious bacteria.

Enhanced methane production via anaerobic digestion assisted with Fe3O4 nanoparticles supported on microporous granular activated carbon

Granular activated carbon (GAC) was used as supporting material for different loading of magnetite (Fe3O4) nanoparticles using the wet impregnation method, for its use as biocatalysts during the anaerobic digestion (AD). The highest responses in terms of methane productivity were achieved with the two modified materials using 1.5% and 3% of Fe3O4. With (1.5%)Fe3O4/GAC, the conversion efficiency to methane was 97.1%, with a methane yield of 388.1 mL CH4/g COD, which was higher than the control without GAC, achieving only 72.1% of conversion and a yield of 286.6 mL CH4/g COD, representing an increment of ∼ 26% for these two parameters with the modified material. Also, the (1.5%)Fe3O4/GAC promotes the highest consumption of volatile fatty acids (VFAs) and ethanol compared to other cultures. The improvement in the AD by the modified materials could be attributable to its surface chemistry composed of a greater extent of Fe2+ and Fe3+, the external surface area, and the electron-accepting capacity. In addition, the close association between microorganisms and the (1.5%)Fe3O4/GAC biocatalyst within the anaerobic medium could be evidence that the direct interspecies electron transfer (DIET) process is occurring.

Diversity and community composition of strictly anaerobic and culturable bacteria from the feces of Styrofoam-fed Tenebrio molitor larvae: a culturomics-based study.

In recent years, researchers have been exploring the plastic-degrading abilities of bacteria residing in the guts of Styrofoam-eating Tenebrio molitor larvae. However, none of the reported strains have displayed highly efficient plastic degradation capabilities, and it's noteworthy that none of the existing studies have focused on strictly anaerobic microbes. In this study, we exclusively fed Styrofoam to T. molitor larvae and examined how this dietary change influence the gut's bacterial community composition, as observed through fecal bacteria using bacterial 16S rRNA gene amplicon sequencing and the small-scale culturomics method with 20 types of anaerobic media under four different conditions. The results revealed a significant shift in the dominant phylogroup from Lactococcus (37.8%) to Escherichia-Shigella (54.7%) when comparing the feces of larvae fed with bran and Styrofoam, as analyzing through the bacterial 16S rRNA gene amplicon sequencing. For small-scale culturomics method, a total of 226 strains of anaerobic bacteria were isolated and purified using the rolling-tube/strictly anaerobic technique. Among them, 226 strains were classified into 3 phyla, 7 classes, 9 orders, 17 families, 29 genera, 42 known species and 34 potential novel species. Interestingly, 24 genera in total, identified through the culturomics method, were not found in the results obtained from amplicon sequencing. Here, we present a collection of culturable anaerobic bacteria from the feces of T. molitor larvae, which might be a promising avenue for investigating the biodegradability of plastics by combining specific strains, either randomly or intentionally, while considering the abundance ratio of the microbial community composition.

Detection of Clostridium perfringens in donor milk at a human breast milk bank: a case report

BackgroundThe breast milk bank is a professional organization that collects donor human milk (DHM) for special medical needs by recruiting qualified breast milk donors. Such organizations are also responsible for the disinfection, processing, testing, storage, distribution, and use of breast milk. As DHM is a biological product, it may get contaminated. Microbiological testing is the final step to determine microbial contamination of DHM. However, a universal method for the microbiological analysis of DHM in breast milk banks globally is lacking.DHM without strict screening may become a potential carrier of pathogens and seriously threaten the health of infants. Clostridium perfringens, a gram-positive anaerobic bacterium, is capable of causing wound infections, including gas gangrene, enteritis/enterocolitis, and enterotoxemia. Here, the first case of C. perfringens detected in DHM has been reported to facilitate the identification of such contamination in breast milk banks.Case presentationA breastfeeding mother donated 3000 mL of milk to the breast milk bank of the First Affiliated Hospital of the Army Medical University(over 2900 beds and patient receiving capacity of over 132,000), Chongqing, China. The milk sample was subjected to microbiological screening using liquid enrichment, followed by anaerobic and aerobic culturing. The results revealed the growth of C. perfringens in the anaerobic culture medium, but no bacteria or yeast-like fungi were observed in the aerobic culture medium. The donor did not exhibit any clinical symptoms, and her routine blood results and body temperature were normal. However, the infant fed with her milk had recurrent bloody stools. Breast milk bank infection control emergency handling as well as environmental sampling and investigation revealed that the cause was contamination of the donor’s home-use breast pump with C. perfringens. The infant no longer experienced bloody stool once the donor changed the breast pump.ConclusionsC. perfringens can enter breast milk from contaminated pumping environments or devices, thus causing illness in infants. The microbiological testing of DHM in breast milk banks can be accomplished using liquid enrichment, along with anaerobic and aerobic culture, which is of immense significance in improving the standards for microbiological screening, DHM safety, and infant health.

Potential of Bacillus subtilis as oxygen-removal agent for biohydrogen production by Clostridium acetobutylicum

Molasses are a source of fermentable sugars, the substrate utilized for this study, as it is a subproduct from sugarcane processing for sucrose recovery. These sugars can be metabolized for bioH2 production by bacterial strains, particularly strict-anaerobe Clostridium acetobutylicum (Clac) and its media preparation requires chemical of O2 removal and N2 flushing to promote anaerobiosis. Bacillus subtilis (Bsub) can deplete O2 from culture media and promotes anaerobiosis, which is an aspect that would benefit from further research. Clac was grown in an anaerobic medium and produced 269 mL of hydrogen at 72 h. By co-culturing Clac and Bsub, 502 mL of bioH2 were produced in a cysteine/N2 flushed medium, while 203 mL of bioH2 at 72 h were produced by aerobic co-culture. Additionally, in an untreated/aerobic conventional growth culture for Clac, no production of H2 was detected, reinforcing the utility of Bsub for anaerobiosis generation.

Process Optimization and Biomethane Recovery from Anaerobic Digestion of Agro-Industry Wastes

Among the sustainable initiatives for renewable energy technologies, anaerobic digestion (AD) is a potential contender to replace fossil fuels. The anaerobic co-digestions of goat manure (GM) with sorghum (SG), cotton gin trash (CGT), and food waste (FW) having different mixing ratios, volumes, temperatures, and additives were optimized in single and two-stage bioreactors. The biochemical methane potential assays (having different mixing ratios of double and triple substrates) were run in 250 mL serum bottles in triplicates. The best-yielding ratio was up-scaled to fabricated 2 L bioreactors. The biodegradability, biomethane recovery, and process efficacy are discussed. The co-digestion of GM with SG in a 70:30 ratio yielded the highest biomethane of 239.3 ± 15.6 mL/gvs, and it was further up-scaled to a two-stage temperature-phased process supplemented with an anaerobic medium and fly ash (FA) in fabricated 2 L bioreactors. This system yielded the highest biomethane of 266.0 mL/gvs, having an anaerobic biodegradability of 67.3% in 70:30 GM:SG co-digestion supplemented with an anaerobic medium. The BMP of the FA-amended treatment may be lower because of its high Ca concentration of 205.74 ± 3.6. The liquid fraction of the effluents can be applied as N and P fertigation. The Ca concentration was found to be 24.3, 25.1, and 6.3 g/kg in GM and GM:SG (TS) and SG solid fractions, respectively, whereas K was found to be 26.6, 10.8, and 7.4 g/kg. The carbon to nitrogen ratio of solid fraction varied between 2.0 and 24.8 for return to the soils to enhance its quality. This study involving feedstock acquisition, characterization, and their anaerobic digestion optimization provides comprehensive information and may assist small farmers operating on-farm anaerobic digesters.

Using walnut shells as low-cost adsorbent materials in an anaerobic filter medium of a De-centralized wastewater treatment system (DEWATS)

The flow of unprocessed sewage through municipal sewers is a great source of water contamination. This study aims to observe the pollutants removal efficiencies of walnut shells as an efficient low-cost adsorbent material compared to gravel materials as an anaerobic filter medium. Two models of the De-Centralized Wastewater Treatment System (DEWATS) were constructed. The wastewater flowing from toilets and handwashing places was connected to anaerobic filters filled with walnut shells and gravel. The efficiency of both filter media in the removal of biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS), nitrate (NO3), and phosphate (PO43), pH and temperature were observed at the influent of the settler tank and then at the effluent of the collection tank (CT). Temperature and pH were within the acceptable limit of wastewater discharge. The results also indicated that the walnut shells filter media was more efficient at removing organic pollutants (TSS 94%, BOD5 88%, COD 85%, Nitrate 57%, phosphate 46%, and TDS 29%) than the gravel (TSS 81%, BOD5 82%, COD 84%, Nitrate 35%, phosphate 38%, and TDS 26%) at the successive stages. The average removal efficiency of the walnut shell was 88% while in the gravel case, it was 83%. The removal efficiency of walnut shell filters was extensively better over the complete experiment compared to gravel filters for the removal of pollutants, representing the high sorption capability of the walnut shell material. The results of this study show that the walnut shells may be a very useful substitute for other conventional fillers for anaerobic treatment in the anaerobic filter of DEWATS.