Investigation and control of biofouling in seawater reverse osmosis desalination membranes by bacteria and their extracellular polysaccharides

Biofouling in seawater reverse osmosis desalination membranes is a phenomenon that needs urgent solutions to effectively mitigate the problem, mainly due to huge economic losses it incurs. To achieve this, a thorough understanding of the microbial community ecology and source of fouling organisms on RO membranes is important. Extracellular polysaccharides produced by bacteria form an important part of the biofilm matrix that govern physical properties and structural integrity of the biofilm. Information about the chemical composition of exopolysaccharides is necessary to employ good control methods. The objectives of this research were defined to better understand biofouling, especially with respect to polysaccharide fouling, and investigate control methods. They were achieved as follows i) Bacterial communities on industrially fouled RO membranes were characterized by next generation sequencing (NGS) on the Illumina Miseq platform; comparisons of microbial ecology were made between treatment groups of membrane samples. ii) Bacteria were isolated from membranes, prefilters and upstream locations of a full-scale desalination plant, and identified by 16S rRNA gene sequencing, matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) and Biolog Gen III systems. Suitable models were then selected from the culture collection based on their dominance in the genetic biofilm community. iii) Exopolysaccharides of model bacteria were purified by acetone precipitation methods and characterized by ion chromatography, Attenuated total reflectance-Fourier transformed infrared spectroscopy (ATR-FTIR) and enzyme linked lectin assay. iv) 2,2-dibromo-3-nitrilopropionamide (DBNPA), a biocide, and two free radical generating compounds, sodium nitroprusside (SNP) and xanthine oxidase, were tested as control agents to disperse biofilms by degrading polysaccharides on industrially fouled membranes. v) For potential use in biological control, bacterial isolates were screened for production of oxidizing enzymes using a xanthine oxidase nitroblue tetrazolium assay. The major findings of this research that contribute to scholarly knowledge are: i) The bacterial community on RO membranes was identified as being dominated by certain bacterial groups, which are known to be associated with unique biofilm forming abilities; mainly Caulobacterales, known to attach irreversibly with holdfast; Sphingobacterales, Rhizobiales and Sphingobacteriia that are known to produce glycosphingolipids; Burkholderiales, known for nitrate-reduction; and Pseudomonadales, proposed to be both primary and secondary colonizers, based on the literature. ii) The cultured bacterial population were dominated by Gammaproteobacteria. MALDI-TOF and 16S rRNA gene sequencing were the most efficient identification methods. The model bacteria were good representatives of biofouling organisms in large scale, within limitations of culture bias. iii) Polysaccharide structures of bacterial isolates revealed the presence of some rare sugars, which are known to form critical components of strong biofilms. iv) Free-radical-generating compounds, SNP and xanthine oxidase, were more effective than the biocide DBNPA in alleviation of fouling by degrading polysaccharides. v) Some bacterial strains like Microbacterium and Exiguobacterium produced xanthine oxidase to significant levels when exposed to hypoxanthine

Association of Inflammatory and Oxidative Stress Markers with Metabolic Syndrome in Asian Indians in India

Metabolic syndrome (MetS) is a primary risk factor for cardiovascular disease and is associated with a proinflammatory state. Here, we assessed the contribution of inflammatory and oxidative stress markers towards prediction of MetS. A total of 2316 individuals were recruited in Phase I of the Indian Atherosclerosis Research Study (IARS). Modified ATPIII guidelines were used for classification of subjects with MetS. Among the inflammatory and oxidative stress markers studied, levels of hsCRP (P < .0001), Neopterin (P = .036), and oxLDL (P < .0001) were significantly higher among subjects with MetS. Among the markers we tested, oxLDL stood out as a robust predictor of MetS in the IARS population (OR 4.956 95% CI 2.504–9.810; P < .0001) followed by hsCRP (OR 1.324 95% CI 1.070–1.638; P = .010). In conclusion, oxLDL is a candidate predictor for MetS in the Asian Indian population

Transcriptomic Analysis Comparing Tumor-Associated Neutrophils with Granulocytic Myeloid-Derived Suppressor Cells and Normal Neutrophils

The role of myeloid cells in supporting cancer growth is well established. Most work has focused on myeloid-derived suppressor cells (MDSC) that accumulate in tumor-bearing animals, but tumor-associated neutrophils (TAN) are also known to be capable of augmenting tumor growth. However, little is known about their evolution, phenotype, and relationship to naïve neutrophils (NN) and to the granulocytic fraction of MDSC (G-MDSC)

LEARN: A multi-centre, cross-sectional evaluation of Urology teaching in UK medical schools

OBJECTIVE: To evaluate the status of UK undergraduate urology teaching against the British Association of Urological Surgeons (BAUS) Undergraduate Syllabus for Urology. Secondary objectives included evaluating the type and quantity of teaching provided, the reported performance rate of General Medical Council (GMC)-mandated urological procedures, and the proportion of undergraduates considering urology as a career. MATERIALS AND METHODS: LEARN was a national multicentre cross-sectional study. Year 2 to Year 5 medical students and FY1 doctors were invited to complete a survey between 3rd October and 20th December 2020, retrospectively assessing the urology teaching received to date. Results are reported according to the Checklist for Reporting Results of Internet E-Surveys (CHERRIES). RESULTS: 7,063/8,346 (84.6%) responses from all 39 UK medical schools were included; 1,127/7,063 (16.0%) were from Foundation Year (FY) 1 doctors, who reported that the most frequently taught topics in undergraduate training were on urinary tract infection (96.5%), acute kidney injury (95.9%) and haematuria (94.4%). The most infrequently taught topics were male urinary incontinence (59.4%), male infertility (52.4%) and erectile dysfunction (43.8%). Male and female catheterisation on patients as undergraduates was performed by 92.1% and 73.0% of FY1 doctors respectively, and 16.9% had considered a career in urology. Theory based teaching was mainly prevalent in the early years of medical school, with clinical skills teaching, and clinical placements in the later years of medical school. 20.1% of FY1 doctors reported no undergraduate clinical attachment in urology. CONCLUSION: LEARN is the largest ever evaluation of undergraduate urology teaching. In the UK, teaching seemed satisfactory as evaluated by the BAUS undergraduate syllabus. However, many students report having no clinical attachments in Urology and some newly qualified doctors report never having inserted a catheter, which is a GMC mandated requirement. We recommend a greater emphasis on undergraduate clinical exposure to urology and stricter adherence to GMC mandated procedures

Inducible Clindamycin Resistance in Staphylococcus aureus Isolated from Nursing and Pharmacy Students

Aims: Emergence of resistant isolates of Staphylococcus aureus (S. aureus) has resulted in failure of clindamycin therapy. The prevalence of inducible clindamycin resistance in S. aureus isolated from nursing students and pharmacy students (representing carriers exposed and not exposed to hospital environment respectively) was evaluated. Materials and Methods: Nasal, throat, and palmar swabs were collected from 119 nursing students and 100 pharmacy students. S. aureus was identified and antibiogram obtained by Clinical and Laboratory Standards Institute guidelines. Inducible clindamycin resistance was detected by the D-test. Results: 36 and 34 individuals in the exposed and non-exposed groups respectively were carriers of S. aureus. 16.7% and 5.9% isolates showed inducible clindamycin resistance in exposed and non-exposed groups, respectively. The percentage of inducible clindamycin resistance was higher among methicillin-resistant S. aureus (MRSA) (27.8%) compared to methicillin-sensitive S. aureus (5.8%). Conclusion: S. aureus isolates resistant to β-lactams can also show inducible clindamycin resistance. Exposure to hospital environment was not found to be a risk factor for carriage of S. aureus with MLSBi phenotype

A Rare Combination of Ovarian and Uterine Leiomyomas with Goblet Cell Carcinoid of the Appendix

We present a case of the rare combination of unilateral ovarian leiomyoma, uterine leiomyoma, and goblet cell carcinoid tumor of the appendix in a premenopausal woman who presented with right iliac pain. Immunohistochemistry study for desmin (muscle marker) and chromogranin and synaptophysin (neuroendocrine markers) confirmed immunophenotyping origin. Interestingly, both tumors showed positive reaction for estrogen receptor. To our knowledge, such a combination has not been reported previously in the literature. In this paper, the pathogenesis and differential diagnosis of both types of tumors are discussed

Lemongrass essential oil gel as a local drug delivery agent for the treatment of periodontitis

Background: It has been long recognized that periodontal diseases are infections of the periodontium, comprising the bacterial etiology, an immune response, and tissue destruction. Treatment strategies aiming primarily at suppressing or eliminating specific periodontal pathogens include adjunct use of local and systemic antibiotics as part of nonsurgical periodontal therapy. Unwanted side effects and resistance of microorganisms toward antibiotics due to their widespread use have modified the general perception about their efficacy. Research in phytosciences has revealed various medicinal plants offering a new choice of optional antimicrobial therapy. Cymbopogon citratus, Stapf. (lemongrass) is a popular medicinal plant. At a concentration ≤2%, lemongrass essential oil inhibits the growth of several kinds of microorganisms including periodontal pathogens, especially the reference strains Actinomyces naeslundii and Porphyromonas gingivalis, which were resistant to tetracycline hydrochloride. Aims: To evaluate the efficacy of locally delivered 2% lemongrass essential oil in gel form as an adjunct to scaling and root planing, as compared to scaling and root planing alone for the treatment of chronic periodontitis. Materials and Methods: 2% Lemongrass essential oil gel was prepared and placed in moderate to deep periodontal pockets after scaling and root planing. Results: Statistically significant reduction in probing depth and gingival index and gain in relative attachment level were noted in the experimental group as compared to the control group at 1 and 3 months. Conclusion: Locally delivered 2% lemongrass essential oil gel offers a new choice of safe and effective adjunct to scaling and root planing in periodontal therapy