Thesis (D.Tech.: Biotechnology)-Dept. of Biotechnology, Durban Institute of Technology, 2005 xx, 175, [14] leaves : ill. ; 30 cm / Previous studies indicate that a mutation in the non-oncogenic p53 gene is epidemiologically linked to human HCC (Ozturk, 1991; Chan et al., 2003). Hsu et al. (1991) found this link in Chinese, South African and Asian patients and Hollstein et al. (1993) found the same gene mutation in Taiwanese patients. The incidence of these aberrations is reported to be about 20- 50% in HCC’s (Kishimoto et al., 1997). There is sufficient evidence to indicate that carotenoids in addition to their well known antioxidant properties (Paiva and Russel, 1999), also affect intercellular communication, immune responses, neoplastic transformations and growth control, and cellular levels of enzymes that detoxify carcinogens (Zhang et al., 1991; Brockman et al., 1992; Pryor et al., 2000). To date studies carried out have used the rat (Foote et al., 1970; Gradelet et al., 1998) and the mule duckling model (Cheng et al., 2001) to show the protective effect of these carotenoids against AFB1 exposure. Of the well known carotenoids, lycopene and beta- carotene occur in abundance in fruits and vegetables and are safe for human consumption. Aflatoxin B1 frequently induces mutations of the p53 gene which is linked to HCC. Although there is much evidence from epidemiological studies linking the beneficial aspects of carotenoids to the prevention of cancer, the cellular and molecular mechanisms need to be understood in order to implement large scale intervention strategies to prevent AFB1 induced carcinoma. The use of chemical or dietary interventions to alter the susceptibility of humans to the actions of carcinogens and to block, retard or reverse carcinogenesis is an emerging chemoprotective strategy for disease prevention (Abdulla and Gruber, 2000; Kensler et al., 2003; Bingham and Riboli, 2004). Chemoprotection by natural products involves maintaining cellular integrity, preventing DNA alterations, activation of p53 suppressor protein and apoptosis. The aim of this study was thus to investigate the cellular and molecular mechanisms by which beta-carotene and lycopene may prevent the AFB1-induced toxic changes in human hepatocytes. In order to achieve this aim, the following objectives were set out: i. To optimise an in vitro system for the evaluation of AFB1 damage to cultured hepatocytes. ii. To determine the biochemical protection offered by beta-carotene and lycopene to AFB1-exposed hepatocytes, by measuring the mitochondrial activity, cell viability and ROS levels using appropriate enzyme assays and flow cytometry. iii. To determine the cellular protection offered by beta-carotene and lycopene to AFB1-exposed hepatocytes, by studying the morphological changes at the structural and ultrastructural levels using phase contrast light and electron microscopy respectively. iv. To determine the molecular protection offered by beta-carotene and lycopene to AFB1-exposed hepatocytes, by detecting apoptotic bodies as genomic markers and measuring the levels of p53 protein and AFB1-N7-guanine adducts produced.

The status of the Baynespruit bacteriological water quality is very alarming - E-coli concentrations have far exceeded the allowable limit of both local and international guidelines for more than a decade, namely 2000-2010. Concentrations of indicator bacteria have been recorded as high as 2419000 cfu/100 ml, whereas guideline levels of E-coli for recreational contact are about 130 cfu/100 ml. In this study, statistical analyses were carried out on data from two sampling points to clarify the seasonal changes and the variability of the pollution. Cross-correlation analyses showed that there was no significant correlation between E-coli concentrations and rainfall in the uMsunduzi catchment. There was also only a weak correlation between the two sampling points which suggests the existence of unregulated sources of pathogenic water pollution between the sampling locations that are independent of the effect that rainfall has on dilution and dispersion of pollution. The data indicates that the population living along the Baynespruit has about a 2% risk of contracting gastrointestinal illness as a result of the pollution in the stream. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.

Quality control procedures during food processing may involve either lengthy enrichment steps, precluding enumeration of bacteria in contaminated food, or direct inoculation of food samples onto appropriate selective media for subsequent enumeration. However, sublethally injured bacteria often fail to grow on selective media, enabling them to evade detection and intervention measures and ultimately threaten the health of consumers. This study compares traditional selective and nonselective agar-based overlays versus two commercial systems (Petrifilm and Easygel) for recovery of injured Escherichia coli B-41560, originally an isolate from ground beef. Bacteria were propagated in tryptic soy broth (TSB), ground beef, or infant milk formula (IMF) to a density of 106-108 CFU/mL, and stressed for six minutes either in lactic acid (pH of 4.5) or heat-shocked for 3 min. at 60°C. Samples were pour- plated in basal layers of either tryptic soy agar (TSA), Sorbitol MacConkey (SMAC), or Violet Red Bile (VRB) agar and resuscitated for 4h prior to addition of agar overlays. Other stressed bacteria were plated directly onto the commercial media Petrifilm and Easygel. Our results indicate that the use of selective and nonselective agar overlays for sensitive recovery and accurate enumeration of E. coli B-41560 is dependent on the stress treatment and food system. These data underscore the need to implement food safety measures that address sublethally- injured bacteria such as E. coli O157:H7, without the use of enrichment steps, in order to avoid underestimation of true densities for target pathogens. / Department of Biology

Thesis (Ph. D.)--Florida State University, 2005. / Advisor: Dr. Timothy M. Logan, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed Sept. 14, 2005). Document formatted into pages; contains xix, 166 pages. Includes bibliographical references.

Staphylococcus aureus is a Gram-positive bacterium predominantly found on human skin and in nasal passages with 20 to 40 percent of the population carrying this organism. Although S. aureus is an unspectacular, non-motile coccoid bacterium, it is a perilous human pathogen associated with both nosocomial and community-acquired infections and it is increasingly becoming virulent and resistant to most antibiotics. It is responsible for several infections such as osteomyelitis, toxin-mediated diseases and bacteraemia, with severe infections arising from strains harbouring antibiotic resistance genes together with virulence genes. S. aureus has been largely confined to hospitals and long-term care facilities, but it is now emerging in the community in places such as recreational beach waters, and occurring in healthy individuals with no associated risk factors. This organism has been reported to be released by swimmers in beaches, suggesting that recreational waters are a potential source of community-acquired S. aureus infections. It is possibly the pathogen of greatest concern due to its intrinsic virulence, its capacity to cause various life-threatening infections, and its ability to adapt to varying environmental conditions. This study was aimed at characterizing S. aureus and methicillin-resistant S. aureus (MRSA) in Port Elizabeth, Port Alfred, Kenton-on-sea and East London beaches of the Eastern Cape Province of South Africa. This was done by investigating the occurrence, antibiotic susceptibilities, antibiotic-resistant genes and virulence genes profiles of S. aureus in the selected beaches. To achieve this aim, 249 beach sand and water samples were obtained from the beaches during the period of April 2015 to April 2016. Physico-chemical parameters of beach water was investigated on site using a multi-parameter ion specific meter during sample collection. Samples were filtered and inoculated on m-Endo agar, m-FC agar and bile aesculin azide agar for total and faecal coliform as well as Enterococci respectively. For isolation of S. aureus and MRSA, samples were cultured on Mannitol salt agar and Staph 24 agar. S. aureus was identified using morphological, Gram staining and molecular (PCR) methods. The isolates were further characterized by determining their antimicrobial resistance profiles, antibiotic resistant genes (mecA, rpoB, blaZ, ermB and tetK genes) and detection of virulent genes encoding intracellular adhesion (icaA), enterotoxin (seaA) and cytolytic toxins (PVL). The majority of study sites passed the directives of physico-chemical standards levels set by WHO during the study period. A total of 143 presumptive isolates were obtained of which 30 (30 percent) were confirmed as S. aureus with 22 (73.3 percent) of these confirmed isolates from marine water and 8 (26.7 percent) from marine sand. Upon culturing on MRSA 2 agar, 15 (50 percent) of isolates showed phonotypic resistance to methicillin. Based on Antimicrobial susceptibility tests, (22/30) 73.3 percent of the isolates showed phonotypic resistance to oxacillin. Out of the 30 isolates, 16 (53.3 percent) were mecA positive and were considered methicillin-resistant S. aureus. S. aureus showed high susceptibility to gentamycin, cefoxithin, levofloxacin, ciprofloxacin, imipenem, and chloramphenicol. A large proportion (36.67 percent to 96.7 percent) of the S. aureus isolates was resistant to penicillin G, ampicillin, oxacillin, tetracycline, clindamycin, rifampicin, vancomycin, sulfamethoxazole-Trimethoprim and erythromycin. Multiple antibiotic resistance (MAR) phenotypes were generated from 7 S. aureus isolates showing resistance to three or more antibiotics. The mecA, rpoB, blaZ, ermB and tetM genes coding for methicillin, rifampicin, βeta-lactam, erythromycin and tetracycline antibiotics resistance was detected in 5 (22.7 percent), 11 (45.8 percent), 16 (55.2 percent), 15 (71.4 percent) and 8 (72.7 percent) respectively. The PVL, icaA and seaA genes coding for virulent determinants were detected in 50, 20 and 13.3 percent of the confirmed isolates respectively. Physico-chemical and faecal indicator bacteria results obtained from this study can assist municipal authorities in developing appropriate management strategies for beaches in the study area. The findings of this study showed that the investigated beaches were contaminated with toxigenic and multi-drug resistant S. aureus strains. This emphasizes the need for the implementation of better control measures to reduce the occurrence of antibiotic resistant S. aureus and of virulent S. aureus strains in recreational waters. In our study it was established that the potential of recreational waters to be reservoirs of S. aureus should not be taken for granted, and it is important that beach goers be educated about this organism as well as other related pathogens that could affect human health, especially immuno-compromised individuals. The community should be educated on antibiotic stewardship and the detrimental effects of antibiotics abuse.

Submitted by EDNEA FREITAS PORTILHO null (edneaportilho@hotmail.com) on 2016-02-29T20:21:35Z No. of bitstreams: 1 total_tese pdf.pdf: 3123535 bytes, checksum: 5e423abcc9b636c6fa5e7443987c0078 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-03-01T13:29:14Z (GMT) No. of bitstreams: 1 portilho_ef_dr_jabo.pdf: 3123535 bytes, checksum: 5e423abcc9b636c6fa5e7443987c0078 (MD5) / Made available in DSpace on 2016-03-01T13:29:14Z (GMT). No. of bitstreams: 1 portilho_ef_dr_jabo.pdf: 3123535 bytes, checksum: 5e423abcc9b636c6fa5e7443987c0078 (MD5) Previous issue date: 2016-02-04 / A segurança alimentar é um assunto que tem sido debatido em todo o mundo, sendo de responsabilidade de todos envolvidos na cadeia produtiva, desde os agricultores, produtores, transportadores, fabricantes, manipuladores, o Estado, e, todas suas esferas governamentais, e os consumidores. Com esse conceito e com a necessidade da descentralização na esfera governamental dos serviços de inspeção para um melhor controle higiênico-sanitário dos estabelecimentos produtores de alimentos de origem animal, assim, sendo, o Serviço de Inspeção Municipal (SIM) é responsável por controlar a qualidade dos produtos de origem animal comercializados no município, e combater a clandestinidade, com isso diminuir os riscos de agravos à saúde transmitidos por microrganismos patogênicos veiculados através destes alimentos. Sendo Rio Verde, GO, o primeiro município goiano a implantar o Serviço de Inspeção Municipal no estado, o presente trabalho realizou um diagnóstico da implantação do SIM no município e da incidência de microrganismos patogênicos em produtos cárneos produzidos no município (quibe e cortes de frango temperado). Concluindo que o serviço de inspeção se encontra em fase de implantação apresentando falhas e necessidades de adequações técnicas, como adequação na legislação vigente à realidade do município, definir padrões e regimentar a profissão do responsável técnico, realizar fiscalizações com maior rigor nas áreas de manipulação e sobre os manipuladores. No diagnóstico de microrganismos patogênicos, foram encontradas prevalências inaceitáveis de Salmonella spp., Bacillus cereus e Listeria spp., comprovando as falhas presentes na manipulação, uma má aplicação dos Manuais de Boas Práticas de Fabricação, demostrando a necessidade de um maior compromisso por parte dos estabelecimentos e responsáveis técnicos com a saúde pública, de se responsabilizarem por mudanças necessárias para a diminuição dos riscos de agravos à saúde da população. / Food safety is an issue that has been debated worldwide, being the responsibility of all involved in the production chain, from farmers, producers, carriers, manufacturers, handlers, the state, and all its spheres of government, and consumers . With this concept and the need for decentralization in the government sphere of inspection services for a better hygienic and sanitary control of establishments producing food of animal origin, thus being the Municipal Inspection Service (SIM) is responsible for controlling the quality of animal products marketed in the city, and combat illegal immigration, thereby decreasing the risk of health problems transmitted by pathogenic microorganisms conveyed by these foods. And Rio Verde Go, the first municipality Goias to implement the Municipal Inspection Service in the state, this paper carried out a diagnosis of SIM deployment in the city and the incidence of pathogens in meat products produced in the municipality (kebab and seasoned chicken cuts ). Concluding that the inspection service is under implementation had shortcomings and needs of technical adaptations, such as adequacy in the current legislation the municipal reality, define standards and regiment the profession's technical manager, perform inspections more closely in the areas of handling and on the handlers. In the diagnosis of pathogenic microorganisms, unacceptable prevalence of Salmonella spp. were found., Bacillus cereus and Listeria spp., Proving the flaws present in the handling, incorrect application of Good Manufacturing Practices Manuals, demonstrating the need for a greater commitment by establishments and technicians in charge of public health, to take responsibility for changes needed to reduce the risks of harm to health.

Made available in DSpace on 2015-03-26T13:46:52Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1174662 bytes, checksum: b8d279c4ce9aa576070293eaf8594b88 (MD5) Previous issue date: 2010-03-24 / Sewage sludge is the major residue produced in Sewage Treatment Stations (STS). One of its possible applications, agricultural use of biosolids - a term which characterizes sewage sludge submitted to hygienization process - presents productive and reduced cost advantages. However, there is a concern of environmental contamination and risk of disease transmission through pathogenic microorganisms. This work aimed to evaluate the decay of pathogenic organisms in hygienized sewage sludge by solarization and lime addition, at field scale, and to estimate the time of permanence of microorganisms in soils fertilized by biosolids in experiments in laboratory conditions. Sewage sludge from a UASB reactor was fortnightly disposed in drying beds and three different lots were monitored, out of which samples were collected for analysis of microbiological parameters every seven days until class B biosolid characteristics were reached, following CONAMA 375/2006 specifications. The parameters monitored were: total solids, pH, humidity, total coliforms, Escherichia coli, Salmonella sp. and helminth eggs. Mixtures in the proportion of 75, 50 and 25% of biosolid with soil were prepared in the laboratory experiments, besides a biosolid treatment. The treatments were placed in 2 kg vases, with 3 repetitions, and submitted to 100 mL irrigation, weekly. The results indicated that hygienization was faster when the lime addition process was applied. Besides, the laboratory experiments confirmed that the biosolid+limed soil mixtures presented a drastic reduction of the remaining pathogenic microorganisms, even after hygienization. The concentrations found at 90 days of treatment with 75% of biosolid were 1.85x102 NMP/g of S.T. (?) for total coliforms, absence of E. coli since the start of monitoring and 0.07 helminth eggs per g of S.T. (?) In the treatment with 75% of solarized biosolid, total coliform concentrations of 5.15x104 NMP/g of S.T. (?) were found at 90 days of experiment; absence of E. coli, at the end of the experiment and between 0.48 and 0.12 helminth eggs per g of S.T. The results obtained in this work indicate the efficiency of both hygienization processes and continuity in pathogen reduction even after their application in the soil, confirming their viability for agricultural use. / O lodo de esgoto é o principal resíduo produzido nas Estações de Tratamento de Esgotos (ETEs). Entre os destinos possíveis, o uso agrícola de biossólidos, nome este que caracteriza o lodo de esgoto submetido a processo de higienização, apresenta vantagens produtivas e de redução de custos; contudo, há preocupação com a possibilidade de contaminação ambiental e risco de transmissão de doenças por microrganismos patogênicos. Este trabalho teve como objetivos avaliar o decaimento de organismos patogênicos em lodo de esgoto higienizado por solarização e caleação, em escala real, e estimar o tempo de permanência dos microorganismos em solos adubados com biossólido em experimentos de bancada. O lodo de um reator UASB era descartado quinzenalmente em leitos de secagem. Foram acompanhados três lotes diferentes, dos quais amostras foram coletadas para análise de parâmetros microbiológicos, a cada sete dias, até alcançar características de biossólido classe B, conforme especificação da CONAMA 375/2006. Os parâmetros monitorados foram: sólidos totais, pH, umidade, coliformes totais, Escherichia coli, Salmonella sp. e ovos de helmintos. Nos experimentos de bancada, foram realizadas misturas na proporção de 75, 50 e 25% de biossólido com solo, além de um tratamento sem biossólido. Os tratamentos foram colocados em vasos com capacidade de 2 kg, com três repetições, e submetidos à irrigação semanal de 100 mL. Os resultados indicaram que a higienização foi mais rápida, quando foi aplicado o processo de caleação. Além disso, constatou-se, nos experimentos de bancada, que as misturas biossólido + solo caleado apresentaram drástica redução dos microrganismos patogênicos remanescentes, mesmo após o processo de higienização. As concentrações encontradas aos 90 dias do tratamento, com 75% de biossólido, foram de 1,85x102 NMP/g de S.T para coliformes totais; ausência de E. coli, desde o princípio do monitoramento; e 0,07 ovos de helmintos por g de S.T. No tratamento com 75% de biossólido solarizado, foram encontradas, aos 90 dias, concentrações de coliformes totais de 5,15x104 NMP/g de S.T.; ausência de E. coli no final do experimento; e ovos de helmintos entre 0,48 e 0,12 ovos por g S.T. Os resultados obtidos indicam que há eficiência em ambos os processos de higienização e continuidade na redução de patógenos, mesmo após a sua aplicação no solo, o que ratifica a sua viabilidade para o uso agrícola.

Orientador: Marcelo Brocchi / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T01:54:39Z (GMT). No. of bitstreams: 1 Gosse_JessicaThandara_M.pdf: 9918536 bytes, checksum: dc4c91a89de0bb62c2d5c3f1c2ea0b3c (MD5) Previous issue date: 2013 / Resumo: O resumo poderá ser visualizado no texto completo da tese digital quando for liberada / Abstract: The abstract is available with the full electronic document when available / Mestrado / Genetica de Microorganismos / Mestra em Genética e Biologia Molecular

Cryptosporidiosis is an infection caused by Cryptosporidium; a protozoan parasite that infects the gastrointestinal tract. The infection is of major public health concern in both developed and developing countries. Faecal samples were collected from 160 in-patient adults, with complaint of diarrhoea, admitted at Victoria hospital in Alice, Nkonkobe Municipality. Twenty apparently healthy subjects were included as controls. All diarrhoea positive patients were interviewed to record socio-demographic information, water supply and animal contact. Initial screening was carried out by microscopy and ELISA to detect positive Cryptosporidium. Genomic DNA was extracted from microscopically positive samples and a PCR reaction was perform to amplify the (18S) SSUrRNA gene for further identification and epidemiology of Cryptosporidium. Data were analysed using Pearson‘s χ2 and Fisher‘s exact test to assess the univariate association between Cryptosporidium infection and the possible risk factors. Of the 180 subjects screened for cryptosporidial infection, Cryptosporidium antigen was detected in 122 giving an overall prevalence of 67.8 percent. In HIV-positive diarrhoea patients, prevalence increased with ages; between 31-43 (mean age 36.5 yr) and 70-82 (mean age 75.8 yr) had a higher prevalence (100 percent) of the antigen than 18-30 (mean age 23.2 yr) and 83-95 (mean age 88.8 yr) (50.0 percent) in HIV-positive diarrhoea patients (P > 0.05). In HIV-negative diarrhoea patients, prevalence was highest in the 18-30 (mean age 23.2 yr) (87.5 percent) and least (35.7 percent) in those aged 83-95 (mean age 88.8 yr) (P > 0.05). Cryptosporidium antigen was higher in females than in males. Of 115 females (mean age 46.7yr) who participated in the study, antigen was detected in 90 (78.2 percent) against 32 (71.1 percent) of 45 males (mean age 42.6yr). None of the 20 apparently healthy control subjects was found to be infected with Cryptosporidium. Cryptosporidium was detected in 27 HIV-positive and 97 HIV-negative diarrhoea patients by any one of the techniques. Antigen detection by ELISA 14 showed the highest positivity 96 (76.8 percent) in HIV- negative and 26 (74.3 percent) in HIV- positive diarrhoea patients. PCR detected eighty-nine (71.2 percent) cases in HIV-negative and 23 (65.7 percent) in HIV-positive patients with diarrhoea. Only 13 (37.1 percent) HIV-positive and 34 (27.2 percent) HIV-negative diarrhoea patients were found positive for Cryptosporidium by modified ZN. No significant difference was observed in sensitivity of antigen detection by ELISA and PCR (96.9 percent) in HIV-negative diarrhoea patients, respectively. Specificity of the staining technique was 88.9 percent in HIV-positive and 96.6 percent in HIV-negative diarrhoea patients. No significant difference was found in specificity of antigen detection by ELISA and PCR in HIV-positive and HIV-negative diarrhoea patients, respectively. Positive predictive value of ZN staining in both HIV-positive and HIV-negative diarrhoea patients (92.3 and 96.9 percent) was statistically higher than ELISA and PCR. No significant difference was observed in negative predictive value of ZN technique for detection of Cryptosporidium between HIV-positive and HIV- negative diarrhoea patients. Differences found in prevalence rates due to water source, suggest that the high infection rates of specific groups are associated with their exposure to the contaminated water supply. The results indicate that Cryptosporidium infection is highly prevalent in adult faecal specimens in the Nkonkobe Municipality, an indication of active infection that is likely to emerge as major human pathogen in this location due to socioeconomic changes which favour transmission. However, sequencing analysis is required to differentiate between Cryptosporidium genotypes in the various outbreaks

Stenotrophomonas maltophilia is increasingly emerging as an opportunistic pathogen of global concern. Due to its inherent resistance to several classes of antibiotics including carbapenems and its ability to acquire mobile resistance elements, treatment of infections caused by S. maltophilia is a constant challenge for clinicians. Trimethoprim-sulphamethoxazole (TMP-SMX) is the generally accepted antibiotic of choice for the treatment of infections caused by this organism, but resistance to the drug is increasingly being reported; hence, the need for alternative therapeutic options. In this study, the antimicrobial susceptibility profile of 110 commensal S. maltophilia isolates obtained from Nkonkobe municipality, Eastern Cape Province, Republic of South Africa was investigated. Twenty-one antibiotics including TMP-SMX and the newer fluoroquinolones; levofloxacin, gatifloxacin and moxifloxacin were included in the antibiotic panel. About 63.4 percent of the isolates were susceptible to TMP-SMX with a resistance rate of 28.2 percent. The fluoroquinolones were more effective with susceptibilities ranging from 76 percent to 94.7 percent. Resistance to the fluoroquinolones ranged from 1.3 percent to 2.7 percent. Levofloxacin was the most effective fluoroquinolone tested. Phenotypic dectection of extended spectrum β-lactamases (ESBLs) showed double disc synergy test (DDST) positivity in 59.5 percent of the isolates. Cefepime was the most sensitive indicator cephalosporin in the DDST with 77.3 percent of suspected ESBL-producing isolates showing cefepime-clavulanic acid synergy. Isolates exhibited nine different ESBL phenotypes, however, PCR amplification of the bla genes revealed four isolates that possessed genes belonging to the CTX-M group (CTX-M-1 and CTX-M-8 groups). ESBL genes are usually carried on mobile elements such as plasmids and transposons which may also bear genes that mediate resistance to aminoglycosides, tetracyclines, TMP-SMX and fluoroquinolones. ESBL positive isolates appeared more susceptible to the fluoroquinolones compared to TMP-SMX but there was no significant relationship between ESBL production and susceptibility to these drugs (p > 0.05). The newer fluoroquinolones are a possible alternative treatment option for S. maltophilia infections in this environment but further studies and clinical investigations are needed to determine the in vivo efficacy of these drugs.