Microbial biofilms: biosurfactants as antibiofilm agents.

Current microbial inhibition strategies based on planktonic bacterial physiology have been known to have limited efficacy on the growth of biofilm communities. This problem can be exacerbated by the emergence of increasingly resistant clinical strains. All aspects of biofilm measurement, monitoring, dispersal, control, and inhibition are becoming issues of increasing importance. Biosurfactants have merited renewed interest in both clinical and hygienic sectors due to their potential to disperse microbial biofilms in addition to many other advantages. The dispersal properties of biosurfactants have been shown to rival those of conventional inhibitory agents against bacterial and yeast biofilms. This makes them suitable candidates for use in new generations of microbial dispersal agents and for use as adjuvants for existing microbial suppression or eradication strategies. In this review, we explore aspects of biofilm characteristics and examine the contribution of biologically derived surface-active agents (biosurfactants) to the disruption or inhibition of microbial biofilms.

Influence of Seasonality and Public-Health Interventions on the COVID-19 Pandemic in Northern Europe.

BACKGROUND: Most government efforts to control the COVID-19 pandemic revolved around non-pharmaceutical interventions (NPIs) and vaccination. However, many respiratory diseases show distinctive seasonal trends. In this manuscript, we examined the contribution of these three factors to the progression of the COVID-19 pandemic. METHODS: Pearson correlation coefficients and time-lagged analysis were used to examine the relationship between NPIs, vaccinations and seasonality (using the average incidence of endemic human beta-coronaviruses in Sweden over a 10-year period as a proxy) and the progression of the COVID-19 pandemic as tracked by deaths; cases; hospitalisations; intensive care unit occupancy and testing positivity rates in six Northern European countries (population 99.12 million) using a population-based, observational, ecological study method. FINDINGS: The waves of the pandemic correlated well with the seasonality of human beta-coronaviruses (HCoV-OC43 and HCoV-HKU1). In contrast, we could not find clear or consistent evidence that the stringency of NPIs or vaccination reduced the progression of the pandemic. However, these results are correlations and not causations. IMPLICATIONS: We hypothesise that the apparent influence of NPIs and vaccines might instead be an effect of coronavirus seasonality. We suggest that policymakers consider these results when assessing policy options for future pandemics. LIMITATIONS: The study is limited to six temperate Northern European countries with spatial and temporal variations in metrics used to track the progression of the COVID-19 pandemic. Caution should be exercised when extrapolating these findings.

A comparison of effects of broad-spectrum antibiotics and biosurfactants on established bacterial biofilms.

Current antibiofilm solutions based on planktonic bacterial physiology have limited efficacy in clinical and occasionally environmental settings. This has prompted a search for suitable alternatives to conventional therapies. This study compares the inhibitory properties of two biological surfactants (rhamnolipids and a plant-derived surfactant) against a selection of broad-spectrum antibiotics (ampicillin, chloramphenicol and kanamycin). Testing was carried out on a range of bacterial physiologies from planktonic and mixed bacterial biofilms. Rhamnolipids (Rhs) have been extensively characterised for their role in the development of biofilms and inhibition of planktonic bacteria. However, there are limited direct comparisons with antimicrobial substances on established biofilms comprising single or mixed bacterial strains. Baseline measurements of inhibitory activity using planktonic bacterial assays established that broad-spectrum antibiotics were 500 times more effective at inhibiting bacterial growth than either Rhs or plant surfactants. Conversely, Rhs and plant biosurfactants reduced biofilm biomass of established single bacterial biofilms by 74-88 and 74-98 %, respectively. Only kanamycin showed activity against biofilms of Bacillus subtilis and Staphylococcus aureus. Broad-spectrum antibiotics were also ineffective against a complex biofilm of marine bacteria; however, Rhs and plant biosurfactants reduced biofilm biomass by 69 and 42 %, respectively. These data suggest that Rhs and plant-derived surfactants may have an important role in the inhibition of complex biofilms.

Unintended Consequences of COVID-19 Non-Pharmaceutical Interventions (NPIs) for Population Health and Health Inequalities.

Since the start of the COVID-19 pandemic in early 2020, governments around the world have adopted an array of measures intended to control the transmission of the SARS-CoV-2 virus, using both pharmaceutical and non-pharmaceutical interventions (NPIs). NPIs are public health interventions that do not rely on vaccines or medicines and include policies such as lockdowns, stay-at-home orders, school closures, and travel restrictions. Although the intention was to slow viral transmission, emerging research indicates that these NPIs have also had unintended consequences for other aspects of public health. Hence, we conducted a narrative review of studies investigating these unintended consequences of NPIs, with a particular emphasis on mental health and on lifestyle risk factors for non-communicable diseases (NCD): physical activity (PA), overweight and obesity, alcohol consumption, and tobacco smoking. We reviewed the scientific literature using combinations of search terms such as 'COVID-19', 'pandemic', 'lockdowns', 'mental health', 'physical activity', and 'obesity'. NPIs were found to have considerable adverse consequences for mental health, physical activity, and overweight and obesity. The impacts on alcohol and tobacco consumption varied greatly within and between studies. The variability in consequences for different groups implies increased health inequalities by age, sex/gender, socioeconomic status, pre-existing lifestyle, and place of residence. In conclusion, a proper assessment of the use of NPIs in attempts to control the spread of the pandemic should be weighed against the potential adverse impacts on other aspects of public health. Our findings should also be of relevance for future pandemic preparedness and pandemic response teams.

Lipopeptide biosurfactants from Paenibacillus polymyxa inhibit single and mixed species biofilms.

Although biofilms are recognised as important in microbial colonisation, solutions to their inhibition are predominantly based on planktonic assays. These solutions have limited efficacy against biofilms. Here, a series of biofilm-orientated tests were used to identify anti-biofilm compounds from marine micro-flora. This led to the isolation of a complex of anti-biofilm compounds from an extract of Paenibacillus polymyxa (PPE). A combination of rpHPLC and mass spectrometry identified the principle components of PPE as fusaricidin B (LI-FO4b) and polymyxin D1, with minor contributions from surfactins. This complex (PPE) reduced the biofilm biomass of Bacillus subtilis, Micrococcus luteus, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus bovis. In contrast, ampicillin was only effective against S. aureus. PPE also inhibited a self-assembling marine biofilm (SAMB) in co-incubation assays by 99.3% ± 1.9 and disrupted established SAMB by 72.4% ± 4.4, while ampicillin showed no significant reduction. The effectiveness of this complex of lipopeptides against single and multispecies biofilms suggests a future role in biofilm prevention strategies.

Phosphoproteome Dynamics of Streptomyces rimosus during Submerged Growth and Antibiotic Production.

Streptomyces rimosus is an industrial streptomycete, best known as a producer of oxytetracycline, one of the most widely used antibiotics. Despite the significant contribution of Streptomyces species to the pharmaceutical industry, most omics analyses have only been conducted on the model organism Streptomyces coelicolor. In recent years, protein phosphorylation on serine, threonine, and tyrosine (Ser, Thr, and Tyr, respectively) has been shown to play a crucial role in the regulation of numerous cellular processes, including metabolic changes leading to antibiotic production and morphological changes. In this study, we performed a comprehensive quantitative (phospho)proteomic analysis during the growth of S. rimosus under conditions of oxytetracycline production and pellet fragmentation. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis combined with phosphopeptide enrichment detected a total of 3,725 proteins, corresponding to 45.6% of the proteome and 417 phosphorylation sites from 230 phosphoproteins. Significant changes in abundance during three distinct growth phases were determined for 494 proteins and 98 phosphorylation sites. Functional analysis revealed changes in phosphorylation events of proteins involved in important cellular processes, including regulatory mechanisms, primary and secondary metabolism, cell division, and stress response. About 80% of the phosphoproteins detected during submerged growth of S. rimosus have not yet been reported in streptomycetes, and 55 phosphoproteins were not reported in any prokaryote studied so far. This enabled the creation of a unique resource that provides novel insights into the dynamics of (phospho)proteins and reveals many potential regulatory events during antibiotic production in liquid culture of an industrially important bacterium. IMPORTANCE Streptomyces rimosus is best known as a primary source of oxytetracycline (OTC). The significant global market value of OTC highlights the need for a better understanding of the regulatory mechanisms that lead to production of this antibiotic. Our study provides, for the first time, a detailed insight into the dynamics of (phospho)proteomic profiles during growth and antibiotic production in liquid culture of S. rimosus. Significant changes in protein synthesis and phosphorylation have been revealed for a number of important cellular proteins during the growth stages that coincide with OTC production and morphological changes of this industrially important bacterium. Most of these proteins have not been detected in previous studies. Therefore, our results significantly expand the insight into phosphorylation events associated with important cellular processes and antibiotic production; they also greatly increase the phosphoproteome of streptomycetes and contribute with newly discovered phosphoproteins to the database of prokaryotic phosphoproteomes. This can consequently lead to the design of novel research directions in elucidation of the complex regulatory network in Streptomyces.

Crocin Inhibits Angiogenesis and Metastasis in Colon Cancer via TNF-α/NF-kB/VEGF Pathways.

Angiogenesis and metastasis play pivotal roles in the progression of cancer. We recently discovered that crocin, a dietary carotenoid derived from the Himalayan crocus, inhibited the growth of colon cancer cells. However, the exact role of crocin on the angiogenesis and metastasis in colorectal cancer remains unclear. In the present study, we demonstrated that crocin significantly reduces the viability of colon cancer cells (HT-29, Caco-2) and human umbilical vein endothelial cells (HUVEC), but was not toxic to human colon epithelial (HCEC) cells. Furthermore, pre-treatment of human carcinoma cells (HT-29 and Caco-2) with crocin inhibited cell migration, invasion, and angiogenesis in concentration -dependent manner. Further studies demonstrated that crocin inhibited TNF-α, NF-κB and VEGF pathways in colon carcinoma cell angiogenesis and metastasis. Crocin also inhibited cell migration, invasion, and tube formation in human umbilical vein endothelial cells (HUVEC) in a concentration -dependent manner. We also observed that crocin significantly reduced the secretion of VEGF and TNF-α induced activation of NF-kB by human colon carcinoma cells. In the absence of TNF-α, a concentration-dependent reduction in NF-kB was observed. Many of these observations were confirmed by in vivo angiogenesis models, which showed that crocin significantly reduced the progression of tumour growth. Collectively, these finding suggest that crocin inhibits angiogenesis and colorectal cancer cell metastasis by targeting NF-kB and blocking TNF-α/NF-κB/VEGF pathways.

Exoproteome of Staphylococcus aureus reveals putative determinants of nasal carriage.

Due to the increasing prevalence of nosocomial and community-acquired antibiotic resistant Staphylococcus aureus (SA), understanding the determinants of SA nasal carriage has become a major imperative. Previous research has revealed many host and bacterial factors that contribute to SA nasal carriage. To assess bacterial factors that facilitate nasal carriage, we compared the exoproteome of a nasal carrier strain of SA to a genetically similar noncarrier strain. Additionally, the carrier strain biofilm exoproteome was also compared against its planktonic counterpart. Using high throughput proteomics, it was observed that the carrier strain of SA secretes a greater number of proteins that may promote successful colonization of the human nose, including cell attachment and immunoevasive proteins, than the noncarrier strain. Similarly, SA carrier strain biofilm exoproteome contains a greater number of immunoevasive proteins than its planktonic counterpart. Analysis of the most abundant immunoevasive proteins revealed that Staphylococcal protein A was present at significantly higher levels in carrier than in noncarrier strains of SA, suggesting an association with nasal carriage. While further analyses of specific differences between carrier and noncarrier strains of SA are required, many of the differentially expressed proteins identified can be considered to be putative determinants of nasal carriage.

RAD51-UTR haplotype genetic polymorphisms and susceptibility to breast cancer in women from Jordanian population.

BACKGROUND: Genetic predisposition to breast cancer (BC) has been extensively explored to achieve an enhanced understanding of the biology of BC. Targeting candidate genes to screen different genetic variants such as RAD51 gene that plays a critical role in DNA repair pathways including the double-strand break repair system is an important task. AIM: To study several single nucleotide polymorphisms (SNPs) within RAD51-UTR gene and to find their relationship with BC risk and prognosis among Jordanian females. MATERIALS AND METHODS: In this case-control study, DNA sequencing technique was used to screen SNPs within the untranslated region (UTR) of RAD51 in 206 cases and 185 controls and the resulting data were statistically analyzed using different types of genetic analyses. Patients' clinical and pathological features were obtained from their medical records to perform genotype-phenotype association analysis. RESULTS: Our findings show a significant association between both SNPs rs528590644, rs1801320 and BC risk (p = 0.016). We estimated the correlation between many of BC prognostic factors and BC risk, and we found an association between rs1801321 and age at first menstruation (p = 0.032) in addition to a strong correlation between age at BC diagnosis and rs1801320 (p = 0.008). CONCLUSION: RAD51-UTR polymorphisms may be involved in BC development and progression.

Exploiting the Metabolism of the Gut Microbiome as a Vehicle for Targeted Drug Delivery to the Colon.

The prevalence of colon-associated diseases has increased significantly over the past several decades, as evidenced by accumulated literature on conditions such as Crohn's disease, irritable bowel syndrome, colorectal cancer, and ulcerative colitis. Developing therapeutics for these diseases is challenging due to physiological barriers of the colon, systemic side effects, and the intestinal environment. Therefore, in a search for novel methods to overcome some of these problems, researchers discovered that microbial metabolism by gut microbiotia offers a potential method for targeted drug delivery This overview highlights several drug delivery systems used to modulate the microbiota and improve colon-targeted drug delivery. This technology will be important in developing a new generation of therapies which harness the metabolism of the human gut microflora.

Cationic polypeptides contribute to the anti-HIV-1 activity of human seminal plasma.

Mucosal surfaces of the reproductive tract as well as their secretions have important roles in preventing sexual transmission of HIV-1. In the current study, the majority of the intrinsic anti-HIV-1 activity of human seminal plasma (SP) was determined to reside in the cationic polypeptide fraction. Antiviral assays utilizing luciferase reporter cells and lymphocytic cells revealed the ability of whole SP to prevent HIV-1 infection, even when SP was diluted 3200-fold. Subsequent fractionation by continuous flow acid-urea (AU)-PAGE and antiviral testing revealed that cationic polypeptides within SP were responsible for the majority of anti-HIV-1 activity. A proteomic approach was utilized to resolve and identify 52 individual cationic polypeptides that contribute to the aggregate anti-HIV-1 activity of SP. One peptide fragment of semenogelin I, termed SG-1, was purified from SP by a multistep chromatographic approach, protein sequenced, and determined to exhibit anti-HIV-1 activity against HIV-1. Anti-HIV-1 activity was transient, as whole SP incubated for prolonged time intervals exhibited a proportional decrease in anti-HIV-1 activity that was directly attributed to the degradation of semenogelin I peptides. Collectively, these results indicate that the cationic polypeptide fraction of SP is active against HIV-1, and that semenogelin-derived peptides contribute to the intrinsic anti-HIV-1 activity of SP.

Streptomyces from traditional medicine: sources of new innovations in antibiotic discovery.

Given the increased reporting of multi-resistant bacteria and the shortage of newly approved medicines, researchers have been looking towards extreme and unusual environments as a new source of antibiotics. Streptomyces currently provides many of the world's clinical antibiotics, so it comes as no surprise that these bacteria have recently been isolated from traditional medicine. Given the wide array of traditional medicines, it is hoped that these discoveries can provide the much sought after core structure diversity that will be required of a new generation of antibiotics. This review discusses the contribution of Streptomyces to antibiotics and the potential of newly discovered species in traditional medicine. We also explore how knowledge of traditional medicines can aid current initiatives in sourcing new and chemically diverse antibiotics.

Subversion of interleukin-1-mediated host defence by a nasal carrier strain of Staphylococcus aureus.

Staphylococcus aureus, a major source of nosocomial and community-acquired infections, has a nasal carriage rate exceeding 25% in the human population. To elucidate host-pathogen interactions pertaining to nasal carriage, we examined the role of interleukin-1 (IL-1) in the colonization of human nasal epithelial cells (NEC) by a nasal carrier strain and a non-carrier strain of S. aureus. Using an organotypic model of the nasal epithelium, we observed that inoculation with a non-carrier strain of S. aureus induced production of IL-1 from NEC, but the expression of this cytokine was significantly reduced when NEC were inoculated with a carrier strain. Moreover, both IL-1alpha and IL-1beta significantly decreased the growth of the nasal carrier strain of S. aureus (P < 0.001, n = 17 to n = 25); however the growth of the non-carrier strain was unaffected. Interestingly, it was found that several nasal carrier strains of S. aureus form quorum-dependent biofilms, which can be partially inhibited when preincubated with IL-1alpha. Taken together these data suggest that, although nasal carrier strains of S. aureus are sensitive to IL-1, they display a significant colonization advantage by both preventing the host from expressing IL-1 and elaborating a protective biofilm.

A Novel Alkaliphilic Streptomyces Inhibits ESKAPE Pathogens.

In an effort to stem the rising tide of multi-resistant bacteria, researchers have turned to niche environments in the hope of discovering new varieties of antibiotics. We investigated an ethnopharmacological (cure) from an alkaline/radon soil in the area of Boho, in the Fermanagh Scarplands (N. Ireland) for the presence of Streptomyces, a well-known producer of antibiotics. From this soil we isolated a novel (closest relative 57% of genome relatedness) Streptomyces sp. capable of growth at high alkaline pH (10.5) and tolerant of gamma radiation to 4 kGy. Genomic sequencing identified many alkaline tolerance (antiporter/multi-resistance) genes compared to S. coelicolor M145 (at 3:1), hence we designated the strain Streptomyces sp. myrophorea, isolate McG1, from the Greek, myro (fragrance) and phorea (porter/carrier). In vitro tests demonstrated the ability of the Streptomyces sp. myrophorea, isolate McG1 to inhibit the growth of many strains of ESKAPE pathogens; most notably carbapenem-resistant Acinetobacter baumannii (a critical pathogen on the WHO priority list of antibiotic-resistant bacteria), vancomycin-resistant Enterococcus faecium, and methicillin-resistant Staphylococcus aureus (both listed as high priority pathogens). Further in silico prediction of antimicrobial potential of Streptomyces sp. myrophorea, isolate McG1 by anti-SMASH and RAST software identified many secondary metabolite and toxicity resistance gene clusters (45 and 27, respectively) as well as many antibiotic resistance genes potentially related to antibiotic production. Follow-up in vitro tests show that the Streptomyces sp. myrophorea, isolate McG1 was resistant to 28 out of 36 clinical antibiotics. Although not a comprehensive analysis, we think that some of the Boho soils' reputed curative properties may be linked to the ability of Streptomyces sp. myrophorea, isolate McG1 to inhibit ESKAPE pathogens. More importantly, further analysis may elucidate other key components that could alleviate the tide of multi-resistant nosocomial infections.

Schistosoma mansoni dermaseptin-like peptide: structural and functional characterization.

Analysis of the Schistosoma mansoni peptidome for immunomodulatory molecules by solvent extraction and reverse-phase HPLC revealed a 27-amino-acid residue peptide from an extract of cercariae. Using matrix-assisted, laser desorption-ionization, time-of-flight mass spectrometry, the peptide yielded a protonated molecular ion [M + H]+ of m/z 2789. The unequivocal sequence was deduced by automated Edman degradation as: DLWNSIKDMAAAAGRAALNAVTGMVNQ. The peptide exhibited an 80.76% identity with dermaseptin 3.1 from the leaf frog Agalychnis annae, and was therefore named Schistosoma mansoni dermaseptin-like peptide (SmDLP). Immunocytochemical staining using a primary antidermaseptin B2 antibody located SmDLP in acetabular glands of cercariae, in and around schistosomula, and in adult worms and their eggs. Dot-blotting confirmed its presence in extracts (cercariae and worms) and excretion/secretion (E/S) products (transforming cercariae and eggs). This was corroborated by use of a MALDI-ToF spectra database of E/S products from cercariae. Functional characterization of the peptide indicated that SmDLP had typical amphipathic antimicrobial peptide properties, i.e., the ability to lyse human erythrocytes causing a decrease in the levels of nitric oxide produced by monocytic cells. This last function strongly suggests that SmDLP plays a vital role in the parasite's immunoevasion strategy. The possibility that schistosomes acquired this gene from amphibians has been discussed by constructing a phylogenetic tree.

Suppression of innate immunity by a nasal carriage strain of Staphylococcus aureus increases its colonization on nasal epithelium.

Nasal carriage of Staphylococcus aureus is an important source of nosocomial infection and community-acquired methicillin-resistant S. aureus (MRSA). Previous studies by our laboratory revealed that nasal carriage of S. aureus is accompanied by subclinical inflammation, which is insufficient to prevent colonization, and that carriage might also be a result of adaptation and selection of certain S. aureus strains to the host's nasal environment. In the present study we observed that a carrier strain of S. aureus preferentially colonizes and attaches to nasal epithelial cells (NEC) compared to a non-carrier S. aureus strain. Conversely, when naive NEC were pretreated with interleukin-1beta for 24 hr, the growth and attachment of the carrier strain of S. aureus were significantly reduced in comparison to the non-carrier strain, emphasizing the pivotal role played by host innate immunity in the initial events of nasal carriage. While both strains up-regulated the expression of the pattern recognition receptor, Toll-like receptor 2 (TLR2), NEC exposed to the nasal carrier strain had a 4-hr delay in TLR2 expression compared with NEC exposed to non-carrier S. aureus. Moreover, even after 20 hr of colonization the expression of two principal epithelial antimicrobial peptides, human beta-defensin-2 and human beta-defensin-3, was negligibly induced in NEC exposed to the nasal carrier strain of S. aureus in comparison to the non-carrier strain. These results suggest that carrier strains of S. aureus retain a competitive advantage over non-carrier strains by delaying the host's innate response to epithelial colonization and infection.