Occurrence of virulence determinants in vibrio cholerae, vibrio mimicus, vibrio alginolyticus, and vibrio parahaemolyticus isolates from important water resources of Eastern Cape, South Africa.

BACKGROUND: Virulence determinants are crucial to the risk assessment of pathogens in an environment. This study investigated the presence of eleven key virulence-associated genes in Vibrio cholerae (n = 111) and Vibrio mimicus (n = 22) and eight virulence determinants in Vibrio alginolyticus (n = 65) and Vibrio parahaemolyticus (n = 17) isolated from six important water resources in Eastern Cape, South Africa, using PCR techniques. The multiple virulence gene indexes (MVGI) for sampling sites and isolates as well as hotspots for potential vibriosis outbreaks among sampling sites were determined statistically based on the comparison of MVGI. RESULT: The PCR assay showed that all the V. cholerae isolates belong to non-O1/non-O139 serogroups. Of the isolates, Vibrio Cholera (84%), V. mimicus (73%), V. alginolyticus (91%) and V. parahaemolyticus (100%) isolates harboured at least one of the virulence-associated genes investigated. The virulence gene combinations detected in isolates varied at sampling site and across sites. Typical virulence-associated determinants of V. cholerae were detected in V. mimicus while that of V. parahaemolyticus were detected in V. alginolyticus. The isolates with the highest MVGI were recovered from three estuaries (Sunday river, Swartkopps river, buffalo river) and a freshwater resource (Lashinton river). The cumulative MVGI for V. cholerae, V. mimicus, V. alginolyticus and V. parahaemolyticus isolates were 0.34, 0.20, 0.45, and 0.40 respectively. The targeted Vibrio spp. in increasing order of the public health risk posed in our study areas based on the MVGI is V. alginolyticus > V. parahaemolyticus > V. cholerae > V. mimicus. Five (sites SR, PA5, PA6, EL4 and EL6) out of the seventeen sampling sites were detected as the hotspots for potential cholera-like infection and vibriosis outbreaks. CONCLUSIONS: Our findings suggest that humans having contact with water resources in our study areas are exposed to potential public health risks owing to the detection of virulent determinants in human pathogenic Vibrio spp. recovered from the water resources. The study affirms the relevancy of environmental Vibrio species to the epidemiology of vibriosis, cholera and cholera-like infections. Hence we suggest a monitoring program for human pathogenic Vibrio spp. in the environment most especially surface water that humans have contact with regularly.

Virulence Signatures, Integrons, and Antibiotic Resistance Genes in Bacterial Strains Recovered from Selected Commercial Dairy Products and Fresh Raw Meat.

Bacterial species responsible for food infections and intoxication are sometimes carried through the food production and processing. Very few published literatures exist on integrons among antibiotic-resistant staphylococcal strains from foods of animal origin in Gauteng Province, South Africa, hence this study. A total of 720 samples (360 meat and 360 dairies) from a community abattoir of a research farm in South Africa, using conventional bacteriological and molecular methods. Nine (9) bacterial strains, including Bacillus subtilis AYO-123, Acinetobacter baumannii AYO-241, Staphylococcus lentus AYO-352, among others were identified and submitted to GenBank. More bacterial strains were recovered from raw meat (90.5%) than dairy products (9.5%). Resistance was shown (0-100%) to Imipenem, Meropenem, Norfloxacin, Clindamycin, and 22 other antibiotics, without any carbapenem-resistant Acinetobacter baumannii and methicillin/vancomycin-resistant Staphylococcus species (MRSS/VRSS). Virulence genes for fibronectin-binding protein A (FnbA) were predominant (56.24%) followed by the circulating nucleic acids (cna) gene (43.75%). Others were staphylococcal enterotoxin A (sea, 41%), staphylococcal enterotoxin B (seb, 23.5%). Co-presence of sea and seb genes occurred in 11.76% of the isolates, but no coa genes was amplified. Antibiotic resistance genes (ARGs), tetK (70.58%), linA (29.4%), and ermA (11.76%) were detected, but none of the mecA and vat genes was amplified. Class 2 integron (50%) was more predominantly detected than integron 1 (25%), but no Class 3 integron was detected. Bacteria with both the detected virulence and antibiotic resistance genes are of potential risks to human health.

Occurrence of herbicides in the aquatic environment and their removal using advanced oxidation processes: a critical review.

Herbicides are chemicals used globally to kill unwanted plants so as to obtain high agricultural yields and good agricultural products. Herbicides are sometimes transported from the farmlands into water bodies mainly through runoffs. These chemicals are recalcitrant, and their accumulation is hazardous to abiotic and biotic components of the ecosystem. At present, the best alternative technology for elimination of herbicides in water is the usage of advanced oxidation processes (AOPs). The AOPs, which are performed homogeneously or heterogeneously, are capable of breaking down complex pollutants in water into carbon dioxide and mineral compounds. In these processes, ·OH is produced and used for degradation process. It is recommended that the total organic carbon (TOC) produced during degradation reaction be monitored because the ‧OH produced or generated can react to form intermediates before complete mineralisation is achieved. Different kinds of AOPs for degradation of herbicides have their specific advantages as well as limitations. This report shows that AOPs are excellent techniques for degradation of herbicides in aqueous solutions, and the mechanisms showed that herbicides were mineralised. The amount and type of photocatalysts, pH of the medium, surface characteristics of the photocatalysts, doping of the photocatalysts, temperature of the medium, concentration of herbicides, presence of competing ions, intensity and irradiation period, and type of oxidants have great influence on the degradation of herbicides in water. Overall, this report showed that most AOPs could not completely degrade herbicides in water and complete degradation can be achieved by developing novel and robust AOPs that will completely mineralise herbicides in water-this will pave way for water and environmental safety.

Evaluation of the research trends on perfluorinated compounds using bibliometric analysis: knowledge gap and future perspectives.

Detection of perfluorinated compounds (PFCs) in the environment has been a global concern because of the risk they pose due to their endocrine-disruptive properties. This study analyzed the global trends and research productivity of PFCs from 1990 to 2021. A total number of 3256 articles on PFCs were retrieved from the Web of Science focusing on different environmental and biological matrices. An increase in the productivity of research on PFCs was observed during the survey period which indicates that more research and publications on this class of contaminants are expected in the future. Evaluating the most productive countries and the number of citations per country on PFCs research shows that China and the United States of America were ranked in first and second places. It was also observed that research on PFCs received the most attention from scientists in developed countries, with little research emerging from Africa. Hence, research on PFCs in developing countries, especially low-income countries should be promoted. Consequently, more research programs should be implemented to investigate PFCs in countries and regions where research on these contaminants is low. The study will help researchers, government agencies and policymakers to tailor future research, allocation of funds to PFCs research and countries' collaboration.

A systematic assessment of research trends on polycyclic aromatic hydrocarbons in different environmental compartments using bibliometric parameters.

Polycyclic aromatic hydrocarbons (PAHs) are a large group of diverse hazardous organic compounds that are relatively stable and widely distributed throughout the world's ecosystems due to various anthropogenic activities. They are generally less soluble in water and have a low vapour pressure, but dissolve easily in adipose tissues; and they bioaccumulate into high concentrations in aquatic animals, thereby exerting a variety of hazardous and lethal effects. Despite the plethora of research studies on these pollutants, only few bibliometric reviews on the subject have been documented in the literature. As a result, the present study aimed to assess the research growth on PAHs-related studies across different ecosystems. Science Citation Index-Expanded of Web of Science was explored to obtain the research studies that were conducted between 1991 and 2020, and RStudio was utilized for the data analysis. Annual productivity increased arithmetically over the years, with a 9.2% annual growth rate and a collaboration index of 2.52. Foremost among the trend topics in this field of study include soil, sediments, biodegradation, bioremediation, bioavailability, and source apportionment. China, USA, Spain, France and Germany were the five top-ranked countries in terms of publications and citations over the three decades investigated; however, Korea, Japan, United Kingdom, Germany, and Canada were ranked as the five leading countries in terms of collaboration per published article (MCP ratio). Therefore, efforts to strengthen international collaboration in this field of study especially among the less participating countries and continents are thus encouraged. The findings of this study are expected to provide future direction for the upcoming researchers in identifying the hot spots in this field of study as well as research leaders whom to seek collaboration in their future research plan.

Non-serogroup O1/O139 agglutinable Vibrio cholerae: a phylogenetically and genealogically neglected yet emerging potential pathogen of clinical relevance.

Somatic antigen agglutinable type-1/139 Vibrio cholerae (SAAT-1/139-Vc) members or O1/O139 V. cholerae have been described by various investigators as pathogenic due to their increasing virulence potential and production of choleragen. Reported cholera outbreak cases around the world have been associated with these choleragenic V. cholerae with high case fatality affecting various human and animals. These virulent Vibrio members have shown genealogical and phylogenetic relationship with the avirulent somatic antigen non-agglutinable strains of 1/139 V. cholerae (SANAS-1/139- Vc) or O1/O139 non-agglutinating V. cholerae (O1/O139-NAG-Vc). Reports on implication of O1/O139-NAGVc members in most sporadic cholera/cholera-like cases of diarrhea, production of cholera toxin and transmission via consumption and/or contact with contaminated water/seafood are currently on the rise. Some reported sporadic cases of cholera outbreaks and observed change in nature has also been tracable to these non-agglutinable Vibrio members (O1/O139-NAGVc) yet there is a sustained paucity of research interest on the non-agglutinable V. cholerae members. The emergence of fulminating extraintestinal and systemic vibriosis is another aspect of SANAS-1/139- Vc implication which has received low attention in terms of research driven interest. This review addresses the need to appraise and continually expand research based studies on the somatic antigen non-serogroup agglutinable type-1/139 V. cholerae members which are currently prevalent in studies of water bodies, fruits/vegetables, foods and terrestrial environment. Our opinion is amassed from interest in integrated surveillance studies, management/control of cholera outbreaks as well as diarrhea and other disease-related cases both in the rural, suburban and urban metropolis.

Characterization of a thermostable and solvent-tolerant laccase produced by Streptomyces sp. LAO.

OBJECTIVES: Decaying wood samples were collected, and actinomycetes were isolated and screened for laccase production. The identity of the efficient laccase-producing isolate was confirmed by using a molecular approach. Fermentation conditions for laccase production were optimized, and laccase biochemical properties were studied. RESULTS: Based on the 16S rRNA gene sequencing and phylogenetic analysis, the isolate coded as HWP3 was identified as Streptomyces sp. LAO. The time-course study showed that the isolate optimally produced laccase at 84 h with 40.58 ± 2.35 U/mL activity. The optimized physicochemical conditions consisted of pH 5.0, ferulic acid (0.04%; v/v), pine back (0.2 g/L), urea (1.0 g/L), and lactose (1 g/L). Streptomyces sp. LAO laccase was optimally active at pH and temperature of 8.0 and 90 °C, respectively, with remarkable pH and thermal stability. Furthermore, the enzyme had a sufficient tolerance for organic solvents after 16 h of preincubation, with laccase activity > 70%. Additionally, the laccase maintained considerable residual activity after pretreatment with 100 mM of chemical agents, including sodium dodecyl sulphate (69.93 ± 0.89%), ethylenediaminetetraacetic acid (93.1 ± 7.85%), NaN3 (96.28 ± 3.34%) and urea (106.03 ± 10.72%). CONCLUSION: The laccase's pH and thermal stability; and robust catalytic efficiency in the presence of organic solvents suggest its industrial and biotechnological application potentials for the sustainable development of green chemistry.

Global bibliometric meta-analytic assessment of research trends on microbial chlorine resistance in drinking water/water treatment systems.

Chlorine is the commonest and cheapest disinfectant used in drinking water and wastewater treatment at household, municipal and industrial levels. However, the uprising of microbial chlorine resistance (MCR) pose critical public health hazard concerns; because, its potentiate exposure to difficult-to-treat resistant pathogens. Therefore, this study aimed at evaluating the burden of MCR in drinking water/wastewater treatment and distribution systems (DWWTDS) via science mapping of research productivity (authors, countries, institutions), thematic conceptual framework, disciplines, research networks and associated intellectual landscape. MCR data were mined from Scopus and Web of Science based on optimized algorithms with the root key term "chlorine* resistant*'' and analysed for pre-set indicator variables. Results revealed 1127 documents from 442 journals and 1430% average growth rate (AGR) of research articles from 2017 to 2019 on MCR. Country-wise, the USA (n = 299), China (n = 119), and Japan (n = 43) ranked in the 1st, 2nd, and 3rd positions respectively, among the top participating countries in MCR research. MCR research had considerable performance in public health and sustainable concern subjects namely, Environmental Sciences & Ecology, Engineering, Microbiology, Water Resources, Biotechnology & Applied Microbiology, Food Science & Technology, Public, Environ & Occupational Health, Chemistry, Infectious Diseases, and Marine & Freshwater Biology; and with noticeable AGR in Environmental Sciences & Ecology (330%) and Infectious Diseases (130%). The study found biofilm-related thrusts (n = 90, 270% AGR) as main research hotspots on MCR. Overall, the study identified and discussed four important thematic areas of public health challenges in MCR that could promote increasing waterborne diseases due to (re)emerging pathogens, enteric viruses and dissemination in DWWTDS. In conclusion, this study provides comprehensive overview of the growing burden of MCR in DWWTDS and standout as a primer of information for researchers on MCR. It recommends direct, intentional and integrated research priorities on MCR to overcome accompanying public health and environmental threats. In addition, chlorine resistance in waterborne fungi have not received research attention. Research activities related to fungal chlorine resistance will be an invaluable future direction in DWWTDS and guide against exposure to waterborne pathogenic fungi and mycotoxins. It is unknown whether chlorine resistance can be acquired by horizontal gene transfer in microorganisms and future research should elucidate this important thrust.

Environmental Water Pollution, Endocrine Interference and Ecotoxicity of 4-tert-Octylphenol: A Review.

4-tert-Octylphenol is a degradation product of non-ionic surfactants alkylphenol polyethoxylates as well as raw material for a number of industrial applications. It is a multimedia compound having been detected in all environmental compartments such as indoor air and surface waters. The pollutant is biodegradable, but certain degradation products are more toxic than the parent compound. Newer removal techniques from environmental waters have been presented, but they still require development for large-scale applications. Wastewater treatment by plant enzymes such as peroxidases offers promise in total removal of 4-tert-octylphenol leaving less toxic degradation products. The pollutant's endocrine interference has been well reported but more in oestrogens than in any other signalling pathways through which it is believed to exert toxicity on human and wildlife. In this paper we carried out a review of the activities of this pollutant in environmental waters, endocrine interference and relevance to its toxicities and concluded that inadequate knowledge of its endocrine activities impedes understanding of its toxicity which may frustrate current efforts at ridding the compound from the environment.

Nanotechnology as a viable alternative for the removal of antimicrobial resistance determinants from discharged municipal effluents and associated watersheds: A review.

Effective and efficient utilization of antimicrobial drugs has been one of the important cornerstone of modern medicine. However, since antibiotics were first discovered by Alexander Fleming about a century ago, the time clock of antimicrobial resistance (AMR) started ticking somewhat leading to a global fear of a possible "post-antimicrobial era". Antibiotic resistance (AR) remains a serious challenge causing global outcry in both the clinical setting and the environment. The huge influence of municipal wastewater effluent discharges on the aquatic environment has made the niche a hotspot of research interest in the study of emergence and spread of AMR microbes and their resistance determinants/genes. The current review adopted a holistic approach in studying the proliferation of antibiotic resistance determinants (ARDs) as well as their impacts and fate in municipal wastewater effluents and the receiving aquatic environments. The various strategies deployed hitherto for the removal of resistance determinants in municipal effluents were carefully reviewed, while the potential for the use of nanotechnology as a viable alternative is explicitly explored. Also, highlighted in this review are the knowledge gaps to be filled in order to curtail the spread of AMR in aquatic environment and lastly, suggestions on the applicability of nanotechnology in eliminating AMR determinants in municipal wastewater treatment facilities are proffered.

Bacillus sp. FPF-1 Produced Keratinase with High Potential for Chicken Feather Degradation.

Chicken feathers are predominantly composed of keratin; hence, valorizing the wastes becomes an imperative. In view of this, we isolated keratinase-producing bacteria and identified them through the 16S rDNA sequence. The process condition for keratinase activity was optimized, and electron micrography of the degradation timelines was determined. Keratinolytic bacteria were isolated and identified as Bacillus sp. FPF-1, Chryseobacterium sp. FPF-8, Brevibacillus sp. Nnolim-K2, Brevibacillus sp. FPF-12 and Brevibacillus sp. FSS-1; and their respective nucleotide sequences were deposited in GenBank, with the accession numbers MG214993, MG214994, MG214995, MG214996 and MG214999. The degree of feather degradation and keratinase concentration among the isolates ranged from 62.5 ± 2.12 to 86.0 ± 1.41(%) and 214.55 ± 5.14 to 440.01 ± 20.57 (U/mL), respectively. In the same vein, 0.1% (w/v) xylose, 0.5% (w/v) chicken feather, an initial fermentation pH of 5.0, fermentation temperature of 25 °C and an agitation speed of 150 rpm, respectively, served as the optimal physicochemical conditions for keratinase activity by Bacillus sp. FPF-1. The time course showed that Bacillus sp. FPF-1 yielded a keratinase concentration of 1698.18 ± 53.99(U/mL) at 120 h. The electron microscopic imaging showed completely structural dismemberment of intact chicken feather. Bacillus sp. FPF-1 holds great potential in the valorization of recalcitrant keratinous biomass from the agro sector into useful products.

Determination and ecological risk assessment of two endocrine disruptors from River Buffalo, South Africa.

4-tert-Octylphenol (4-tOP) and triclosan (TCS) are endocrine disruptors which have been detected in environmental matrices such as air, soil and water at ultra-low levels. Exposure to endocrine disruptors may account at least in part, for the global increase in the incidence of non-communicable diseases like cancers and diabetes and may also lead to an imbalance in the aquatic ecosystem. River Buffalo is an important natural resource in the Eastern Cape of South Africa serving more than half a million people. The presence of the two compounds in the river water hitherto unknown was investigated during winter seasons using solid-phase extraction and gas chromatography-mass spectrometric techniques. The sampling points differed by some physicochemical parameters. The concentration of 4-tOP ranged 0-755 ng/L, median value 88.1 ng/L while that of TCS ranged 0-1264.2 ng/L and the median value was 82.1 ng/L. Hazard quotient as an index of exposure risk varied according to daphnids Ëƒ fish Ëƒ algae for 4-tOP exposure while HQ for TCS exposure was algae > daphnids = fish showing that both compounds were capable of causing imbalance in the aquatic ecosystem. Graphical abstract.

Prevalence and capsular type distribution of Streptococcus agalactiae isolated from pregnant women in Namibia and South Africa.

BACKGROUND: Streptococcus agalactiae or Group B Streptococcus (GBS) is the leading cause of neonatal morbidity and mortality resulting in septicaemia, bacteraemia and meningitis. Long term problems in children range from loss of hearing to mental retardation. While Intrapartum Antibiotic Prophylaxis (IAP) has reduced the incidence of S. agalactiae infection, it still remains the leading cause of disease in neonates. GBS has ten capsular types whose distribution varies across the world. Therefore, this study sought to determine the prevalence of GBS in Namibia and South Africa amongst pregnant women between 35 and 37 weeks gestation and elucidate the capsular types. METHODS: Lower vaginal and rectal swabs were collected from pregnant women between 35 and 37 weeks gestation. Five hundred and thirty pregnant women were recruited into the study in Windhoek, Namibia while one hundred pregnant women were recruited in the Eastern Cape, South Africa. The swabs were cultured on 5% sheep blood agar (Biomerieux, New Jersey, USA) for isolation of GBS. Presumptive isolates were confirmed using both the Vitek (2) and molecular techniques targeting the scpB gene. Capsular typing was performed in a multiplex PCR with capsular specific primer pairs. RESULTS: The prevalence of GBS in Namibia was 13.6 and 37% in South Africa respectively. In both countries most women were dually colonised with GBS. Capsular types II, III and V were the most prevalent. CONCLUSIONS: The prevalence of GBS in Namibia was lower than in South Africa in this study. The prevalence in both countries was not different from those reported in other African countries and around the world. The predominant capsular types in this study are the ones commonly associated with adverse maternal outcomes.

Agrowastes utilization by Raoultella ornithinolytica for optimal extracellular peroxidase activity.

The industrial applications and prospects of microbial peroxidase are on the upwards trend, thus necessitating the search for sources with high turnaround time. Actinobacterial species have been a major source of peroxidase for the obvious reasons of having robust metabolite expression capabilities. However, other bacteria species have been underexplored for peroxidase production, hence the motivation for the investigation into the peroxidase production potential of Raoultella ornithinolytica OKOH-1 (KX640917). The bacteria expressed optimum specific peroxidase activity of 16.48 ± 0.89 U mg-1 , which is higher than those previously reported. The optimal fermentation conditions were pH 5 (3.44 ± 0.64 U mL-1 ), incubation temperature of 35 °C (5.25 ± 0.00 U mL-1 ), and agitation speed of 150 rpm (9.45 ± 2.57 U mL-1 ), with guaiacol and ammonium chloride as the best inducer and nitrogen supplement, respectively. On valorization of agrowastes as a sole carbon source for the secretion of peroxidase, sawdust gave the best peroxidase yield (15.21 ± 2.48 U mg-1 ) under solid-state fermentation. Also, a nonperoxide-dependent enzyme activity, which suggests probable laccase activity, was observed. The ability of the bacteria to utilize agrowastes is highly economical and as well a suitable waste management strategy. Consequently, R. ornithinolytica OKOH-1 is a promising industrial strain with dexterity for enhanced peroxidase production.

Neuroprotective effects of some seaweeds against Zn - induced neuronal damage in HT-22 cells via modulation of redox imbalance, inhibition of apoptosis and acetylcholinesterase activity.

Zinc plays an important role in neuronal signaling and neurotransmission. However, dyshomeostasis of this metal or its accumulation in the brain has been linked with neurological disorders such as Alzheimer's disease and Parkinson's disease. In this study, the neuroprotective effects of Ecklonia maxima (KPM), Gracilaria gracilis (GCL), Ulva lactuca (ULT) and Gelidium pristoides (MNP) in Zn -induced neurotoxicity in HT-22 cells was examined. Cells were treated with Zinc sulphate and/or aqueous - ethanol extracts and cell viability, apoptosis, acetylcholinesterase activity, including some antioxidant enzymes (catalase and superoxide dismutase activity) and glutathione (GSH) levels were determined. Malondialdehyde and nitric oxide levels produced in the Zn and/or seaweed extract treated cells were also determined. Prior treatment with the seaweed extracts improved cell viability and inhibited Zn - induced cell death. Acetylcholinesterase activity was significantly high in Zn treated cells compared to the control. Pre-treatment with the seaweed extracts triggered a decrease in acetylcholinesterase activity in Zn - treated cells. Furthermore, treatment with Zn caused a significant reduction in GSH levels as well as a decrease in superoxide dismutase and catalase activities. In contrast, the seaweed extract increased antioxidant enzyme activities and GSH levels. An increase in malondialdehyde and nitric oxide levels was also reversed after treatment with the seaweed extracts. These results suggest that the seaweed extracts improved cholinergic transmission disrupted by Zn - induced neurotoxicity and protected the cells against oxidative damage and neuroinflammation. The neuroprotective effects of the seaweed extracts could be linked to their bioactive constituents. Hence these seaweeds are potential sources of active ingredients with neuroprotective potentials and could be used for the development of functional foods and/or nutraceuticals.

Macroalgae as a Valuable Source of Naturally Occurring Bioactive Compounds for the Treatment of Alzheimer's Disease.

Alzheimer's disease (AD) is a neurological condition that affects mostly aged individuals. Evidence suggests that pathological mechanisms involved in the development of AD are associated with cholinergic deficit, glutamate excitotoxicity, beta-amyloid aggregation, tau phosphorylation, neuro-inflammation, and oxidative damage to neurons. Currently there is no cure for AD; however, synthetic therapies have been developed to effectively manage some of the symptoms at the early stage of the disease. Natural products from plants and marine organisms have been identified as important sources of bioactive compounds with neuroprotective potentials and less adverse effects compared to synthetic agents. Seaweeds contain several kinds of secondary metabolites such as phlorotannins, carotenoids, sterols, fucoidans, and poly unsaturated fatty acids. However, their neuroprotective effects and mechanisms of action have not been fully explored. This review discusses recent investigations and/or updates on interactions of bioactive compounds from seaweeds with biomarkers involved in the pathogenesis of AD using reports in electronic databases such as Web of science, Scopus, PubMed, Science direct, Scifinder, Taylor and Francis, Wiley, Springer, and Google scholar between 2015 and 2019. Phlorotannins, fucoidans, sterols, and carotenoids showed strong neuroprotective potentials in different experimental models. However, there are no data from human studies and/or clinical trials.

Inhibitory effects of Azadirachta indica secondary metabolites formulated cosmetics on some infectious pathogens and oxidative stress radicals.

BACKGROUND: Infectious diseases, particularly those due to multi-drug resistant bacterial strains are almost impossible to cure globally. In this study we investigated the inhibitory effects of Azadirachta indica A. Juss secondary metabolites (AISM) formulated soap and cream for management of infectious and oxidative stress-related diseases (OSD). METHODS: The antibacterial, radical scavenging and cytotoxic effects of the neem cosmetics were examined by serial dilution, spectrophotometric and hemolytic techniques respectively, while the AISM in the essential oils (EOs) were elucidated by Gas chromatography-mass spectrometry (GC-MS) and retention index. RESULTS: The neem cosmetics without AISM exhibited bacteriostatic effects against five reference bacterial strains (Staphylococcus aureus, Listeria ivanovii, Enterobacter cloacae, Mycobacterium smegmatis, and Streptococcus uberis) and two confirmed multi-drug resistant bacterial strains (Vibrio paraheamolyticues, Escherichia coli 180) at 0.80 mg/mL. Conversely, at less than 0.50 mg/mL the neem soap produced with AISM demonstrated bactericidal effects against most of these test pathogens linked to infectious diseases. The neem soap containing AISMs displayed noteworthy effects in scavenging radicals associated with OSD at < 1.76 mg/mL. The cosmetics were not toxic to human red blood cells below 0.70 mg/ mL. To our known, the AISM predominantly caryophyllene (30.02%), phytol (14.12%), elemene (13.40%) and linoleic acid (10.5%) exceptional inhibitory effects in neem cosmetics are reported here for the first time. CONCLUSION: The study indicates that apart from traditional uses of A. indica, the EO contained potent bioactive AISM and feasible as an antimicrobial agent, an alternative to synthetic antioxidant, likewise considered novel in the pharmaceutical, cosmetics industries and as food preservatives.

The activity of commercial antimicrobials, and essential oils and ethanolic extracts of Olea europaea on Streptococcus agalactiae isolated from pregnant women.

BACKGROUND: Streptococcus agalactiae also known as Group B Streptococcus (GBS) is a major cause of disease in pregnant women and new born babies where it causes early and late onset disease characterised by sepsis, pneumonia and meningitis. Ten to 37 % of pregnant women in the world are colonised with GBS while intrapartum antibiotic prophylaxis has led to significant reduction in early onset disease. The increase in drug resistant microorganisms has become a major threat. Development of vaccines is still in progress so there is need for new and safer alternatives to treatment. METHODS: Benzyl penicillin, Ampicillin, Cefotaxime, Ceftriaxone, Levofloxacin, Erythromycin, Clindamycin, Linezolid, Vancomycin, Tetracycline and Cotrimoxazole, Olea europaea leaf extracts and essential oil were tested against GBS isolates from South Africa and Namibia. RESULTS: The isolates showed 100% sensitivity to benzyl penicillin, ampicillin, ceftriaxone, levofloxacin, linezolid, vancomycin, O. europaea leaf extracts and essential oils. Only one isolate (0.6%) was resistant to cefotaxime and 23.4 and 10.4% were resistant to clindamycin and erythromycin respectively. CONCLUSION: GBS isolates showed sensitivity to O. europaea extracts at low minimum inhibitory concentrations. Β lactams are still the drugs of choice for treatment of GBS disease but O. europaea extracts potent as an alternative source of antimicrobials.

Utilization of agroindustrial wastes for the production of laccase by Achromobacter xylosoxidans HWN16 and Bordetella bronchiseptica HSO16.

Agroindustrial residual lignocellulosic biomaterial provides an economical and renewable natural bioresource for the large-scale, gainful biofuel production, as well as the production of fine bulk chemicals, which may include industrial biocatalysts. To this end, the laccase-inducing aptitude of some agroindustrial, lignocellulosic residues were appraised in submerged fermentation batch culture of two woodland betaproteobacteria (Hb9c; Achromobacter xylosoxidans HWN16, Hb16c; Bordetella bronchiseptica HSO16). Significant fermentation factors for laccase production were identified following a one-variable-at-a-time: OVAT screening method, levels of significant factors were optimized using response surface methodology: RSM. Mandarin peelings: MP and wheat bran: WB were suitable substrates for laccase production in Hb9c; 29.4 U/mL and Hb16c; 28.2 U/mL, respectively. However, the numerical optimization of significant factors for laccase production in both isolates presented an overall maximum laccase output encountered throughout the study (Hb9c; 169.39 U/mL, Hb16c; 45.22 U/mL), albeit the simulated conditions of the statistical model were outside the design space of the algorithm such as pH 5, 0.5 g MP, 100 rpm, 0.25 g NaNO3 for Hb9c and pH 3, 2.5 g WB, 50 rpm, 0.05 g yeast extract for Hb16c. Furthermore, a record 17.5 and 15.54 fold increase in laccase turnover depicts the astuteness of the statistical method in the valorization of these lignocellulosic residues for enhanced laccase production, hence, the incorporation of these outcomes at industrial scales might yield tremendous outputs.

Aptitude of Oxidative Enzymes for Treatment of Wastewater Pollutants: A Laccase Perspective.

Natural water sources are very often contaminated by municipal wastewater discharges which contain either of xenobiotic pollutants and their sometimes more toxic degradation products, or both, which frustrates the universal millenium development goal of provision of the relatively scarce pristine freshwater to water-scarce and -stressed communities, in order to augment their socioeconomic well-being. Seeing that both regulatory measures, as regards the discharge limits of wastewater, and the query for efficient treatment methods remain unanswered, partially, the prospects of enzymatic treatment of wastewater is advisable. Therefore, a reconsideration was assigned to the possible capacity of oxidative enzymes and the respective challenges encountered during their applications in wastewater treatment, and ultimately, the prospects of laccase, a polyphenol oxidase that oxidizes aromatic and inorganic substrates with electron-donating groups in treatment aromatic contaminants of wastewater, in real wastewater situations, since it is assumed to be a vehicle for a greener community. Furthermore, the importance of laccase-driven catalysis toward maintaining mass-energy balance, hence minimizing environmental waste, was comprehensibly elucidated, as well the strategic positioning of laccase in a model wastewater treatment facility for effective treatment of wastewater contaminants.