Carlos Bezuidenhout - Academia.edu (original) (raw)

Papers by Carlos Bezuidenhout

Heliyon

Background: Dementia, including Alzheimer's disease (AD), is one of the most burdensome medical c... more Background: Dementia, including Alzheimer's disease (AD), is one of the most burdensome medical conditions. Usually, the reviews that aim at calculating the prevalence of dementia include estimates from studies without assessing their methodological quality. Alzheimer's Disease International (ADI) proposed a score to assess the methodological quality of population-based studies aimed at estimating the prevalence of dementia. During the last three years, the European Commission has funded three projects (Eurodem, EuroCoDe, and ALCOVE) in order to estimate the prevalence of dementia in Europe. Objective: The aim of this study was to perform a systematic review and meta-analysis of data on the prevalence of dementia in Europe derived from studies that included only subjects with a diagnosis of dementia according to the DSM IV criteria, and that had a high quality score according to ADI criteria. Methods: We considered the studies selected by the two projects EuroCoDe (1993-2007) and Alcove (2008-2011), and we performed a new bibliographic search. For the systematic review, we only selected the subset of articles that included subjects with a diagnosis of dementia according to the DSM IV criteria. The studies were qualitatively assessed using the ADI tool. Results: The meta-analysis considered 9 studies that were carried out in Europe between 1993 and 2018 including a total of 18,263 participants, of which 2,137 were diagnosed with dementia. The prevalence rate standardized for age and sex resulted 7.1%. Discussion: This is the first systematic review on the prevalence of dementia in Europe considering only high-quality studies adopting the same diagnostic criteria (i.e., DSM IV).

International Journal of Infectious Diseases

Attribution License, which permits unrestricted use, distribution, and reproduction in any medium... more Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The aim of this study was to isolate and identify environmental bacteria from various raw water sources as well as the drinking water distributions system in Mafikeng, South Africa, and to determine their antibiotic resistance profiles. Water samples from five different sites (raw and drinking water) were analysed for the presence of faecal indicator bacteria as well as Aeromonas and Pseudomonas species. Faecal and total coliforms were detected in summer in the treated water samples from the Modimola dam and in the mixed water samples, with Pseudomonas spp. being the most prevalent organism.Themost prevalent multiple antibiotic resistance phenotype observed was KF-AP-C-E-OT-K-TM-A. All organisms tested were resistant to erythromycin, trimethoprim, and amoxicillin. All isolates were susceptible to ciprofloxacin and faecal coliforms and Pseud...

International journal of pharmaceutics, Jan 30, 2017

Antimicrobial resistance is an imminent threat to the effective prevention and treatment of bacte... more Antimicrobial resistance is an imminent threat to the effective prevention and treatment of bacterial infections and alternative antimicrobial strategies are desperately needed. Antimicrobial peptides (AMPs) may be promising alternatives to current antibiotics or act as adjuvants to enhance antibiotic potency. Additionally, the use of biodegradable lipid nanoparticles can enhance the antibacterial activity of antibiotics and antimicrobial peptides. In this study, the interaction of the AMPs, nisin Z and melittin, with conventional antibiotics was investigated on Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli. The effectiveness of nanostructured lipid carriers (NLCs) for the entrapment of nisin Z was also evaluated. Findings revealed that nisin Z exhibited additive interactions with numerous conventional antibiotics. Notable synergism was observed for novobiocin-nisin Z combinations. The addition of the non-antibiotic adjuvant EDTA significantly improved the a...

Journal of basic microbiology, Jan 21, 2017

Insecticidal proteins expressed by genetically modified Bt maize may alter the enzymatic and micr... more Insecticidal proteins expressed by genetically modified Bt maize may alter the enzymatic and microbial communities associated with rhizosphere soil. This study investigated the structure and enzymatic activity of rhizosphere soil microbial communities associated with field grown Bt and non-Bt maize. Rhizosphere soil samples were collected from Bt and non-Bt fields under dryland and irrigated conditions. Samples were subjected to chemical tests, enzyme analyses, and next generation sequencing. Results showed that nitrate and phosphorus concentrations were significantly higher in non-Bt maize dryland soils, while organic carbon was significantly higher in non-Bt maize irrigated field soil. Acid phosphatase and β-glucosidase activities were significantly reduced in soils under Bt maize cultivation. The species diversity differed between fields and Bt and non-Bt maize soils. Results revealed that Actinobacteria, Proteobacteria, and Acidobacteria were the dominant phyla present in these ...

Ecotoxicology, 2016

To test whether metal-tolerant and metal-sensitive earthworm specimens could be an inherent part ... more To test whether metal-tolerant and metal-sensitive earthworm specimens could be an inherent part of metal-free earthworm populations, (i) we used DNA barcoding to identify and categorize earthworms from 8 populations of the standard test species Eisenia andrei, and (ii) the earthworms carrying three of the identified COI haplotypes (named Hap1, hap3 and Hap3) were paired up and exposed to Cd in order to assess the difference in Cd sensitivity between the breeding pairs. A total of six breeding pairs were exposed to 0, 25, 50 and 100 mg Cd/kg for 4 weeks at 20°C. The survival of the breeding pairs, their change in biomass and cocoon production were assessed. For all of the endpoints assessed, the results indicated that couple 6 (Hap3 9 Hap3) was the most sensitive breeding pair whereas couple 4 (Hap1 9 Hap3) was the least sensitive one. The analysis of Cd tissue contents revealed that with increasing Cd concentration, Cp6 (Hap3 9 Hap3) could accumulate significantly more Cd than any other breeding pair (p B 0.01). Our findings indicate that E. andrei may harbour intrinsically Cd-tolerant and Cd-sensitive individuals and that this may be due to individual differences in Cd accumulation kinetics. In the context of ecotoxicological testing, our results underline the importance of using genetically diverse populations in laboratory testing to prevent generating flawed data from genetically homogeneous laboratory stocks. Although we do not regard the present mitochondrial haplotypes as proxy for possibly nuclear encoded traits, we discuss the necessity of a standardised earthworm barcoding protocol that could help not only to confirm the taxonomy of laboratory earthworm stocks but also to select genetically diverse stocks suitable for laboratory testing.

African Zoology, Oct 13, 2013

Water Science & Technology

The widespread and indiscriminate use of antibiotics has led to the development of antibiotic res... more The widespread and indiscriminate use of antibiotics has led to the development of antibiotic resistance in pathogenic, as well as commensal, microorganisms. Resistance genes may be horizontally or vertically transferred between bacterial communities in the environment. The recipient bacterial communities may then act as a reservoir of these resistance genes. In this study, we report the incidence of antibiotic resistance in enteric bacteria isolated from the Mhlathuze River and the distribution of genetic elements that may be responsible for the observed antibiotic resistance. The resistance of the enteric bacteria isolated over a period of one year showed that resistance to the older classes of antibiotics was high (94.7% resistance to one antibiotic and 80.8% resistance to two antibiotics). Furthermore, antibiotic resistance data of the environmental isolates showed a strong correlation (r = 0.97) with data obtained from diarrhoea patients. PCR based methods demonstrated that cla...

South African Journal of Science

Toxigenic Fusarium species, studied mainly for the damage they cause to commercial crops, have re... more Toxigenic Fusarium species, studied mainly for the damage they cause to commercial crops, have received scant research attention in the context of small-scale food production. In this regard home gardens are an important source of nutrition for resource-poor urban families in Africa. We have investigated the presence of Fusarium in household food gardens in a peri-urban setting in the Rustenburg district of South Africa. Standard techniques were employed for the isolation and morphological species identification of Fusarium species from various sources, namely, maize, soil, air and naturally growing morogo vegetables, thepe and lerotho. Nine Fusarium species with mycotic and mycotoxigenic potential were specifically targeted for detection: F. verticillioides, F. proliferatum, F. solani, F. subglutinans and F. oxysporum were predominantly isolated from maize, air, soil and morogo vegetables. All species were isolated in significantly higher numbers from localities in proximity to mai...

South African Journal of Science

Wild African dark-green leafy vegetables (morogo) are an important constituent of the traditional... more Wild African dark-green leafy vegetables (morogo) are an important constituent of the traditional starch-based African diet. Three wild morogo types were sampled from different geographical regions in South Africa to determine their mineral, total polyphenol, total carotenoid and beta-carotene contents. Mineral and trace element compositions were determined using inductively coupled argon plasma mass spectrometry (ICP-MS). Concentrations of total carotenoids and total phenolics were measured by spectrophotometry and beta-carotene concentrations by high performance liquid chromatography (HPLC). In comparison with values reported for commercial spinach and swiss chard, results from the present study indicate relatively high calcium and magnesium concentrations in the wild morogo. Total carotenoid concentrations in the three morogo types were comparable with that of spinach. Beta-carotene concentrations were highest in Amaranthus hybridus, but this value was lower than those reported f...

Journal of Biotechnology, 2008

Leishmania major causative agent of zoonotic cutaneous leishmaniasis (CL) shows several diverse c... more Leishmania major causative agent of zoonotic cutaneous leishmaniasis (CL) shows several diverse clinical manifestations (Seimenis et al., 2006). Likewise, heterogeneity in genomic pattern of isolates has been reported in isolates collected from different endemic areas (Elfari et al., 2005). This polymorphism may cause difficulty in selection of reliable strain for development of a candidate vaccine. The present study aimed at choosing an ideal strain of L. major induces reliable virulence and Th1 response. Isolates from lesion of patients residing in four endemic areas of L. major in Iran including Damghan (north), Kashan (center), Dehloran (west), and Shiraz (south) were analyzed by PCR, RAPD-PCR and SSCP. Four isolates with distinct patterns as well as WHO reference strain were inoculated to five groups of C57BL/6 mice and their pathogenicity and specific immune responses were compared, after 4 weeks. Measurement of parasite burden by limiting dilution, cytokine production by ELISA and T cell phenotyping by flow cytometry were performed on the lymph node (LN) cells culture. Data showed the lowest and highest parasite burden in LN of mice infected with Damghan and Kashan strains, respectively. The ratio of gammainterferon/interleukin-4 was high in LN cell culture of mice infected with Shiraz and Damghan strains. Moreover, high levels of IL-12p70 and high ratio of CD4 + T/CD8 + T cells (>1) produced by all strains. Results indicated that Damghan strain which induced lowest parasite load and high ratio of gamma-IFN/IL-4 in LN cell culture might be an ideal candidate strain for vaccine studies in leishmaniasis.

Journal of Applied Microbiology, 2012

Aims: To investigate the presence of methicillin-resistant Staphylococcus aureus (MRSA) in untrea... more Aims: To investigate the presence of methicillin-resistant Staphylococcus aureus (MRSA) in untreated hospital wastewaters (UHWW), their transmission into the receiving sewage treatment plant (STP) and survival through the STP treatment. Methods and Results: Over eight consecutive weeks of sampling, we isolated 224 Staph. aureus strains from UHWW-1, UHWW-2 and its receiving STP inlet (SI) and post-treatment outlet (SO). These strains were typed using the PhP typing method and RAPD-PCR and tested for their antibiotic resistance patterns. Resistance to cefoxitin and the presence of mecA gene identified MRSA isolates. In all, 11 common (C) and 156 single (S) PhP-RAPD types were found among isolates, with two multidrug resistant (MDR) C-types found in H2, SI and SO. These C-type strains also showed resistance to cefoxitin and vancomycin. The mean number of antibiotics to which the strains from UHWW were resistant (5Á14 ± 2) was significantly higher than the STP isolates (2Á9 ± 1Á9) (P < 0Á0001). Among the 131 (68%) MRSA strains, 24 were also vancomycin resistant. MDR strains (including MRSA) were more prevalent in hospital wastewaters than in the STP. Conclusion: This study provides evidence of the survival of MRSA strains in UHWWs and their transit to the STP and then through to the final treated effluent and chlorination stage. Significance and Impact of the Study: This preliminary study identifies the need to further investigate the load of MRSA in hospitals' wastewaters and possible their survival in STPs. From a public health point of view, this potential route of hospital MRSA dissemination is of great importance.

Environmental Toxicology, 2006

Culture-independent methods employed in fungal genetic studies using in vitro amplification (PCR)... more Culture-independent methods employed in fungal genetic studies using in vitro amplification (PCR) and analysis of specific genes or gene fragments have proved to be useful for detection, identification, and molecular taxonomy of various plant pathogens including Fusarium spp. This approach may be faster than culture-dependent methods, and could especially be of value for the rapid detection of slowgrowing toxin-producing species in food samples. The present study was aimed at the development and evaluation of multiplex PCR-based methods for the detection and identification of potential fumonisinproducing Fusarium spp. in traditional morogo-leafy vegetables supplementing the maize-based staple diet of rural communities in South Africa. In these rural subsistence settings, some morogo plants grow as weeds in maize fields where they might become contaminated with potential fumonisin-producing Fusarium strains before being collected for consumption. Substances released by senescent vegetables could induce toxin production during storage. Using fumonisin-positive MRC Fusarium verticillioides strains as reference cultures, the following primer sets for the detection of specific gene fragments in fumonisin-positive Fusarium spp. were evaluated: (i) the conserved transcription elongation factor gene (EF-1), (ii) the FUM1 gene encoding polyketide synthase for fumonisin B 1 production, and (iii) 18S rRNA gene. Preliminary results indicated that, these DNA fragments were amplified from MRC reference strains as well as Fusarium spp. isolated from morogo. The annealing temperature for the multiplex PCR was 558C and each reaction contained 25 pmol of each of the primer sets EF and FUM1 and 12.5 pmol of the 18S primer set. The detection limit of the individual primers was up to 1 ng and for the multiplex up to 10 ng. This demonstrates the potential of this method for the detection of potential fumonisin-positive strains.

Water Supply

Water quality affected by polluted surface runoff from agricultural settings, storm-water as well... more Water quality affected by polluted surface runoff from agricultural settings, storm-water as well as sewage from urban locations, and mining in the North West Province are reasons for concern. Similar situations may exist in areas elsewhere that have similar water issues and impacts. This study aimed to evaluate the water quality of the Loopspruit River by analysing the physico-chemical and microbiological parameters of the water. Bacterial diversity was the highest in less polluted areas of the Loopspruit River. Dominating at all the sites tested were Proteobacteria, followed by Bacteroidetes, Cyanobacteria, Actinobacteria and Verrucomicrobia. Predicted metagenome analysis revealed a correlation between the physico-chemical parameters and observed taxonomic units (OTU). Temperature had a negative correlation with Patescibacteria, Nanoarchaeaeota and Firmicutes (p < 0.05). The negative correlation was strongest with Patescibacteria. Sulphate had a strong correlation with Fusobact...

Heliyon

Background: Dementia, including Alzheimer's disease (AD), is one of the most burdensome medical c... more Background: Dementia, including Alzheimer's disease (AD), is one of the most burdensome medical conditions. Usually, the reviews that aim at calculating the prevalence of dementia include estimates from studies without assessing their methodological quality. Alzheimer's Disease International (ADI) proposed a score to assess the methodological quality of population-based studies aimed at estimating the prevalence of dementia. During the last three years, the European Commission has funded three projects (Eurodem, EuroCoDe, and ALCOVE) in order to estimate the prevalence of dementia in Europe. Objective: The aim of this study was to perform a systematic review and meta-analysis of data on the prevalence of dementia in Europe derived from studies that included only subjects with a diagnosis of dementia according to the DSM IV criteria, and that had a high quality score according to ADI criteria. Methods: We considered the studies selected by the two projects EuroCoDe (1993-2007) and Alcove (2008-2011), and we performed a new bibliographic search. For the systematic review, we only selected the subset of articles that included subjects with a diagnosis of dementia according to the DSM IV criteria. The studies were qualitatively assessed using the ADI tool. Results: The meta-analysis considered 9 studies that were carried out in Europe between 1993 and 2018 including a total of 18,263 participants, of which 2,137 were diagnosed with dementia. The prevalence rate standardized for age and sex resulted 7.1%. Discussion: This is the first systematic review on the prevalence of dementia in Europe considering only high-quality studies adopting the same diagnostic criteria (i.e., DSM IV).

International Journal of Infectious Diseases

Attribution License, which permits unrestricted use, distribution, and reproduction in any medium... more Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The aim of this study was to isolate and identify environmental bacteria from various raw water sources as well as the drinking water distributions system in Mafikeng, South Africa, and to determine their antibiotic resistance profiles. Water samples from five different sites (raw and drinking water) were analysed for the presence of faecal indicator bacteria as well as Aeromonas and Pseudomonas species. Faecal and total coliforms were detected in summer in the treated water samples from the Modimola dam and in the mixed water samples, with Pseudomonas spp. being the most prevalent organism.Themost prevalent multiple antibiotic resistance phenotype observed was KF-AP-C-E-OT-K-TM-A. All organisms tested were resistant to erythromycin, trimethoprim, and amoxicillin. All isolates were susceptible to ciprofloxacin and faecal coliforms and Pseud...

International journal of pharmaceutics, Jan 30, 2017

Antimicrobial resistance is an imminent threat to the effective prevention and treatment of bacte... more Antimicrobial resistance is an imminent threat to the effective prevention and treatment of bacterial infections and alternative antimicrobial strategies are desperately needed. Antimicrobial peptides (AMPs) may be promising alternatives to current antibiotics or act as adjuvants to enhance antibiotic potency. Additionally, the use of biodegradable lipid nanoparticles can enhance the antibacterial activity of antibiotics and antimicrobial peptides. In this study, the interaction of the AMPs, nisin Z and melittin, with conventional antibiotics was investigated on Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli. The effectiveness of nanostructured lipid carriers (NLCs) for the entrapment of nisin Z was also evaluated. Findings revealed that nisin Z exhibited additive interactions with numerous conventional antibiotics. Notable synergism was observed for novobiocin-nisin Z combinations. The addition of the non-antibiotic adjuvant EDTA significantly improved the a...

Journal of basic microbiology, Jan 21, 2017

Insecticidal proteins expressed by genetically modified Bt maize may alter the enzymatic and micr... more Insecticidal proteins expressed by genetically modified Bt maize may alter the enzymatic and microbial communities associated with rhizosphere soil. This study investigated the structure and enzymatic activity of rhizosphere soil microbial communities associated with field grown Bt and non-Bt maize. Rhizosphere soil samples were collected from Bt and non-Bt fields under dryland and irrigated conditions. Samples were subjected to chemical tests, enzyme analyses, and next generation sequencing. Results showed that nitrate and phosphorus concentrations were significantly higher in non-Bt maize dryland soils, while organic carbon was significantly higher in non-Bt maize irrigated field soil. Acid phosphatase and β-glucosidase activities were significantly reduced in soils under Bt maize cultivation. The species diversity differed between fields and Bt and non-Bt maize soils. Results revealed that Actinobacteria, Proteobacteria, and Acidobacteria were the dominant phyla present in these ...

Ecotoxicology, 2016

To test whether metal-tolerant and metal-sensitive earthworm specimens could be an inherent part ... more To test whether metal-tolerant and metal-sensitive earthworm specimens could be an inherent part of metal-free earthworm populations, (i) we used DNA barcoding to identify and categorize earthworms from 8 populations of the standard test species Eisenia andrei, and (ii) the earthworms carrying three of the identified COI haplotypes (named Hap1, hap3 and Hap3) were paired up and exposed to Cd in order to assess the difference in Cd sensitivity between the breeding pairs. A total of six breeding pairs were exposed to 0, 25, 50 and 100 mg Cd/kg for 4 weeks at 20°C. The survival of the breeding pairs, their change in biomass and cocoon production were assessed. For all of the endpoints assessed, the results indicated that couple 6 (Hap3 9 Hap3) was the most sensitive breeding pair whereas couple 4 (Hap1 9 Hap3) was the least sensitive one. The analysis of Cd tissue contents revealed that with increasing Cd concentration, Cp6 (Hap3 9 Hap3) could accumulate significantly more Cd than any other breeding pair (p B 0.01). Our findings indicate that E. andrei may harbour intrinsically Cd-tolerant and Cd-sensitive individuals and that this may be due to individual differences in Cd accumulation kinetics. In the context of ecotoxicological testing, our results underline the importance of using genetically diverse populations in laboratory testing to prevent generating flawed data from genetically homogeneous laboratory stocks. Although we do not regard the present mitochondrial haplotypes as proxy for possibly nuclear encoded traits, we discuss the necessity of a standardised earthworm barcoding protocol that could help not only to confirm the taxonomy of laboratory earthworm stocks but also to select genetically diverse stocks suitable for laboratory testing.

African Zoology, Oct 13, 2013

Water Science & Technology

The widespread and indiscriminate use of antibiotics has led to the development of antibiotic res... more The widespread and indiscriminate use of antibiotics has led to the development of antibiotic resistance in pathogenic, as well as commensal, microorganisms. Resistance genes may be horizontally or vertically transferred between bacterial communities in the environment. The recipient bacterial communities may then act as a reservoir of these resistance genes. In this study, we report the incidence of antibiotic resistance in enteric bacteria isolated from the Mhlathuze River and the distribution of genetic elements that may be responsible for the observed antibiotic resistance. The resistance of the enteric bacteria isolated over a period of one year showed that resistance to the older classes of antibiotics was high (94.7% resistance to one antibiotic and 80.8% resistance to two antibiotics). Furthermore, antibiotic resistance data of the environmental isolates showed a strong correlation (r = 0.97) with data obtained from diarrhoea patients. PCR based methods demonstrated that cla...

South African Journal of Science

Toxigenic Fusarium species, studied mainly for the damage they cause to commercial crops, have re... more Toxigenic Fusarium species, studied mainly for the damage they cause to commercial crops, have received scant research attention in the context of small-scale food production. In this regard home gardens are an important source of nutrition for resource-poor urban families in Africa. We have investigated the presence of Fusarium in household food gardens in a peri-urban setting in the Rustenburg district of South Africa. Standard techniques were employed for the isolation and morphological species identification of Fusarium species from various sources, namely, maize, soil, air and naturally growing morogo vegetables, thepe and lerotho. Nine Fusarium species with mycotic and mycotoxigenic potential were specifically targeted for detection: F. verticillioides, F. proliferatum, F. solani, F. subglutinans and F. oxysporum were predominantly isolated from maize, air, soil and morogo vegetables. All species were isolated in significantly higher numbers from localities in proximity to mai...

South African Journal of Science

Wild African dark-green leafy vegetables (morogo) are an important constituent of the traditional... more Wild African dark-green leafy vegetables (morogo) are an important constituent of the traditional starch-based African diet. Three wild morogo types were sampled from different geographical regions in South Africa to determine their mineral, total polyphenol, total carotenoid and beta-carotene contents. Mineral and trace element compositions were determined using inductively coupled argon plasma mass spectrometry (ICP-MS). Concentrations of total carotenoids and total phenolics were measured by spectrophotometry and beta-carotene concentrations by high performance liquid chromatography (HPLC). In comparison with values reported for commercial spinach and swiss chard, results from the present study indicate relatively high calcium and magnesium concentrations in the wild morogo. Total carotenoid concentrations in the three morogo types were comparable with that of spinach. Beta-carotene concentrations were highest in Amaranthus hybridus, but this value was lower than those reported f...

Journal of Biotechnology, 2008

Leishmania major causative agent of zoonotic cutaneous leishmaniasis (CL) shows several diverse c... more Leishmania major causative agent of zoonotic cutaneous leishmaniasis (CL) shows several diverse clinical manifestations (Seimenis et al., 2006). Likewise, heterogeneity in genomic pattern of isolates has been reported in isolates collected from different endemic areas (Elfari et al., 2005). This polymorphism may cause difficulty in selection of reliable strain for development of a candidate vaccine. The present study aimed at choosing an ideal strain of L. major induces reliable virulence and Th1 response. Isolates from lesion of patients residing in four endemic areas of L. major in Iran including Damghan (north), Kashan (center), Dehloran (west), and Shiraz (south) were analyzed by PCR, RAPD-PCR and SSCP. Four isolates with distinct patterns as well as WHO reference strain were inoculated to five groups of C57BL/6 mice and their pathogenicity and specific immune responses were compared, after 4 weeks. Measurement of parasite burden by limiting dilution, cytokine production by ELISA and T cell phenotyping by flow cytometry were performed on the lymph node (LN) cells culture. Data showed the lowest and highest parasite burden in LN of mice infected with Damghan and Kashan strains, respectively. The ratio of gammainterferon/interleukin-4 was high in LN cell culture of mice infected with Shiraz and Damghan strains. Moreover, high levels of IL-12p70 and high ratio of CD4 + T/CD8 + T cells (>1) produced by all strains. Results indicated that Damghan strain which induced lowest parasite load and high ratio of gamma-IFN/IL-4 in LN cell culture might be an ideal candidate strain for vaccine studies in leishmaniasis.

Journal of Applied Microbiology, 2012

Aims: To investigate the presence of methicillin-resistant Staphylococcus aureus (MRSA) in untrea... more Aims: To investigate the presence of methicillin-resistant Staphylococcus aureus (MRSA) in untreated hospital wastewaters (UHWW), their transmission into the receiving sewage treatment plant (STP) and survival through the STP treatment. Methods and Results: Over eight consecutive weeks of sampling, we isolated 224 Staph. aureus strains from UHWW-1, UHWW-2 and its receiving STP inlet (SI) and post-treatment outlet (SO). These strains were typed using the PhP typing method and RAPD-PCR and tested for their antibiotic resistance patterns. Resistance to cefoxitin and the presence of mecA gene identified MRSA isolates. In all, 11 common (C) and 156 single (S) PhP-RAPD types were found among isolates, with two multidrug resistant (MDR) C-types found in H2, SI and SO. These C-type strains also showed resistance to cefoxitin and vancomycin. The mean number of antibiotics to which the strains from UHWW were resistant (5Á14 ± 2) was significantly higher than the STP isolates (2Á9 ± 1Á9) (P < 0Á0001). Among the 131 (68%) MRSA strains, 24 were also vancomycin resistant. MDR strains (including MRSA) were more prevalent in hospital wastewaters than in the STP. Conclusion: This study provides evidence of the survival of MRSA strains in UHWWs and their transit to the STP and then through to the final treated effluent and chlorination stage. Significance and Impact of the Study: This preliminary study identifies the need to further investigate the load of MRSA in hospitals' wastewaters and possible their survival in STPs. From a public health point of view, this potential route of hospital MRSA dissemination is of great importance.

Environmental Toxicology, 2006

Culture-independent methods employed in fungal genetic studies using in vitro amplification (PCR)... more Culture-independent methods employed in fungal genetic studies using in vitro amplification (PCR) and analysis of specific genes or gene fragments have proved to be useful for detection, identification, and molecular taxonomy of various plant pathogens including Fusarium spp. This approach may be faster than culture-dependent methods, and could especially be of value for the rapid detection of slowgrowing toxin-producing species in food samples. The present study was aimed at the development and evaluation of multiplex PCR-based methods for the detection and identification of potential fumonisinproducing Fusarium spp. in traditional morogo-leafy vegetables supplementing the maize-based staple diet of rural communities in South Africa. In these rural subsistence settings, some morogo plants grow as weeds in maize fields where they might become contaminated with potential fumonisin-producing Fusarium strains before being collected for consumption. Substances released by senescent vegetables could induce toxin production during storage. Using fumonisin-positive MRC Fusarium verticillioides strains as reference cultures, the following primer sets for the detection of specific gene fragments in fumonisin-positive Fusarium spp. were evaluated: (i) the conserved transcription elongation factor gene (EF-1), (ii) the FUM1 gene encoding polyketide synthase for fumonisin B 1 production, and (iii) 18S rRNA gene. Preliminary results indicated that, these DNA fragments were amplified from MRC reference strains as well as Fusarium spp. isolated from morogo. The annealing temperature for the multiplex PCR was 558C and each reaction contained 25 pmol of each of the primer sets EF and FUM1 and 12.5 pmol of the 18S primer set. The detection limit of the individual primers was up to 1 ng and for the multiplex up to 10 ng. This demonstrates the potential of this method for the detection of potential fumonisin-positive strains.

Water Supply

Water quality affected by polluted surface runoff from agricultural settings, storm-water as well... more Water quality affected by polluted surface runoff from agricultural settings, storm-water as well as sewage from urban locations, and mining in the North West Province are reasons for concern. Similar situations may exist in areas elsewhere that have similar water issues and impacts. This study aimed to evaluate the water quality of the Loopspruit River by analysing the physico-chemical and microbiological parameters of the water. Bacterial diversity was the highest in less polluted areas of the Loopspruit River. Dominating at all the sites tested were Proteobacteria, followed by Bacteroidetes, Cyanobacteria, Actinobacteria and Verrucomicrobia. Predicted metagenome analysis revealed a correlation between the physico-chemical parameters and observed taxonomic units (OTU). Temperature had a negative correlation with Patescibacteria, Nanoarchaeaeota and Firmicutes (p < 0.05). The negative correlation was strongest with Patescibacteria. Sulphate had a strong correlation with Fusobact...