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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Enhancement of extracellular enzyme secretion in Bacillus lichenformis NCIB 6346

Grieveson, A. P. H. January 1988 (has links)
No description available.
2

A study of the facultative thermophile Bacillus coagulans

Ball, A. S. January 1986 (has links)
No description available.
3

The protoplast mediated genetics of thermophilic bacilli

Dunn, R. M. January 1987 (has links)
No description available.
4

Pollutant pressure effects on the diversity, stability and function of the soil microbial community

Girvan, Martina Susanna January 2000 (has links)
This study aims to investigate the link between genetic functioning and diversity, and to establish a relationship, if any, between that diversity and the stability of the community. Extreme transient perturbations were performed, using repeat chloroform fumigations, to reduce the community to its lowest genetic level (0.7% of the DNA of the control population). Severe reduction in community diversity and selection for bacilli was initially observed, the community subsequently recovered (6 months) to its previous diversity but was altered in community composition, bacilli were no longer dominant. Perturbations using benzene resulted in a reduced genetic diversity (16S rDNA and DGGE) which did not recover (after 4 weeks). However, full recovery was observed for culturable cell numbers, DNA concentration and community level physiological profile (Biolog)., suggesting high levels of genetic redundancy within soil. Investigation of the relationship between diversity and stability was performed by perturbing soils with naturally differing levels of diversity (Sourhope>Boyndie) to equivalent toxicity, using copper and benzene. Large decreases in biomass were observed for both soils after benzene perturbation. Assuming successful equivalent toxicity, the genetic diversity of the naturally more diverse soil was more resistant to benzene perturbation than the less diverse soil. The broad scale function of both benzene-treated soil communities was unaffected (14C-labelled wheat shoot mineralisation). Narrow niche function was impaired for both soils (14C-labelled 2,4-DCP mineralisation). The Sourhope soil recovered this function by the end of the experiment, but Boyndie did not. The genetic diversity of both soils was resistant to copper perturbation despite biomass decreases. Initial shifts in physiological profiles of both soils was observed but rapidly returned to that of the control. In conclusion, diversity-stability relationships may exist in soil communities, despite generally being an extremely robust system.
5

Quality of sputum collected for Acid-Fast Bacilli (AFB) test from patients at Dr. George Mukhari Hospital, Pretotia

Iqbal, R January 2010 (has links)
Thesis (M Med.(Family Medicine))--University of Limpopo, 2010. / OBJECTIVE: In order to obtain optimal results using sputum smear microscopy for acid-fast bacilli (AFB) detection in the diagnosis of pulmonary tuberculosis (PTB), good quality sputum with an adequate volume of at least 5.0ml is required. An inadequate amount of sputum sample may result cases of active PTB being missed. This study was aimed at showing that a single sputum sample of at least 5.0ml would lower the chances of missing active PTB cases, and increase sputum smear positivity by microscopy thus enabling prompt treatment of PTB, and restricting its transmission. METHODS: An analytical cross sectional study was carried out at Dr George Mukhari Hospital in Pretoria, South Africa. Two sputum samples, one of 5.0ml and the other with 2.0ml were collected from each adult patient suspected of having active PTB. Sputum collection was supervised and patients were given instructions on how to enhance sputum expectoration. Sputum samples were processed using the N-acetyl-L-cysteine (NaLc-NaOH) method and stained with Auramine O. Sputum analysis was done with the aid of fluorescence microscopy. Following microscopy, both the 2.0ml and 5.0ml specimens were sent for culture using the Middlebrook broth medium, and culture results were available after 6-8 weeks. Using the culture results as gold standard, the yield through microscopy of the 2.0ml specimen versus the 5.0ml specimen for each patient were compared and analysed. RESULTS: A Total of 330 sputum samples were analysed of which 77 were found to be culture positive. A sensitivity of 76.6% and specificity of 99.6% was obtained for AFB test in the 5.0ml specimens; while in the 2.0ml samples the sensitivity was 75.3%, with a specificity of 99.2%. The difference in the smear positivity rate of 76.6% obtained using the 5.0ml sputum specimen compared to the 75.3% obtained using the 2.0ml specimen from patients suspected of having TB in this study was statistically insignificant – ascribable to the small sample size. CONCLUSION: In this study, the volume of sputum collected did not determine a better AFB test yield in the diagnosis of pulmonary tuberculosis in patients suspected of having TB.
6

In Vitro Interactions of Amikacin and Beta-Lactam Antibiotics Against Amikacin-Resistant Gram-Negative Bacilli

Alvarez, Salvador, Jones, Mary, Holtsclaw-Berk, Shirley, Berk, Steven L. 01 January 1988 (has links)
We tested 42 strains of amikacin-resistant gram-negative bacilli with amikacin in combination with six beta-lactam antibiotics using the checkerboard and time kill curve techniques. Synergism was demonstrated with time-killing curve in 43-68% of the strains tested. Ceftazidime plus amikacin was the most active combination by the checkerboard technique, while amikacin-cefoperazone was the most active combination by the time-killing curve technique against Pseudomonas aeruginosa. Discrepancies were found between the results of the two methods used.
7

Avaliação da multirresistência a antibióticos e produção de ESBL e carbapenemases em bacilos gram-negativos de efluente hospitalar e urbano / Evaluation of antibiotic multi-resistance and production of ESBL and carbapenemases in gram-negative bacilli of hospital and urban effluent

Zagui, Guilherme Sgobbi 29 March 2019 (has links)
A multirresistência aos antibióticos observada em bacilos gram-negativos é um grave problema de saúde pública devido a alta morbidade e mortalidade apresentada, especialmente em instituições assistenciais de saúde. Como consequência do intenso uso de antibióticos, a multirresistência a esses fármacos é principalmente mediada por enzimas hidrolisantes, onde destaca-se as enzimas ?-lactamases, principal mecanismo de resistência aos ?-lactâmicos verificado em bacilos gram-negativos. Os esgotos de origem hospitalar e de estações de tratamento de esgoto (ETE) são considerados como reservatórios de bactérias multirresistentes pela presença de antibióticos que as selecionam e por favorecem a transmissão de determinantes de resistência. Nesse sentido, o presente estudo objetivou avaliar a multirresistência a antibióticos e a produção de enzimas ?-lactamases em bacilos gram-negativos isolados de efluente hospitalar e da estação de tratamento de esgoto, na cidade de Ribeirão Preto, SP. No hospital terciário, amostras de esgotos foram coletadas dos ambulatórios, das enfermarias e da junção do esgoto hospitalar. Na ETE, amostras foram coletadas na caixa de entrada do esgoto bruto e após ao tratamento. Dez microlitros foram semeados em ágar MacConkey, SalmonellaShigella, Cetrimide e TCBS e a identificação dos bacilos gram-negativos foi realizada pelo kit Bactray®. O teste de susceptibilidade aos antibióticos foi realizado pelo método de discodifusão em ágar. A detecção fenotípica de bacilos produtores de ESBL foi realizada pelos testes de sinergia de disco-duplo e disco combinado com ácido clavulânico, e para detecção de isolados produtores de carbapenemases foi utilizado os testes de disco combinado com ácido fenilborônico e EDTA e o teste Blue Carba. A PCR foi utilizada para amplificação dos genes codificadores de ESBL e carbapenemases. No total, 45 bacilos gram-negativos foram isolados, sendo as espécies Klebsiella pneumoniae e Pseudomonas aeruginosa as de maiores prevalências. Ampla resistência foi verificada aos antibióticos ?-lactâmicos, sendo a resistência ao aztreonam, a cefepime e a cefotaxima mais expressiva nos isolados do esgoto hospitalar, com diferenças estatisticamente significante (p<0,05). O fenótipo multidroga resistente foi atribuído a 33,3%, nos isolados exclusivamente do esgoto hospitalar, com diferença estatisticamente significante (p = 0,0025) em relação aos isolados do esgoto da ETE. Genes de ?-lactamases foram encontrados em 35,6% das bactérias, sendo o blaKPC e blaTEM os de maiores ocorrências, ambos em 17,8% dos isolados, e os genes blaSHV e blaCTX-M em 13,3% e 8,9%. Somente em um isolado de Enterobacter cloacae no esgoto tratado da ETE foi identificado o gene blaSHV, os demais isolados portadores dos genes de ?-lactamases foram encontrados no esgoto hospitalar. Os dados obtidos neste estudo são importantes levando em consideração que no Brasil o esgoto hospitalar pode ser lançado in natura na rede coletora municipal, no entanto, acredita-se que tal permissão favorece a disseminação da multirresistência bacteriana, posto que, os resultados demonstram alta frequência de bactérias portadoras de genes de resistência a antibióticos no esgoto hospitalar estudado. Assim, a implementação do tratamento de efluentes hospitalares, especialmente os de hospitais terciários, e adicionalmente ao tratamento da ETE evitaria a propagação dessas bactérias no ambiente e de impactar negativamente os recursos hídricos / Antibiotic multi-resistance observed in Gram-negative bacilli is a serious public health problem due to high morbidity and mortality, especially in health care institutions. As a consequence of the intense use of antibiotics, multi-resistance to these drugs is mainly mediated by hydrolyzing enzymes, in which ?-lactamases, the main ?-lactam resistance mechanism observed in Gramnegative bacilli, are prominent. Hospital sewage and wastewater treatment plants (WWTP) are considered reservoirs of multiresistant bacteria by the presence of antibiotics that select these bacteria and favor the transmission of resistance determinants. In this sense, the present study aimed to evaluate the antibiotics multi-resistance and the production of ?-lactamase enzymes in Gram-negative bacilli isolated from hospital effluent and the wastewater treatment plants in Ribeirão Preto city, SP. In the tertiary hospital, sewage samples from the outpatient clinics, rooms patients and the hospital sewage junction were collected. In the WWTP, raw and treated sewage were collected. Ten microliters were seeded on MacConkey, Salmonella-Shigella, Cetrimide and TCBS agar and the identification of Gram-negative bacilli was performed by the Bactray® kit. Antibiotic susceptibility test was performed by agar-diffusion method. Phenotypic detection of ESBL-producing bacilli was performed by double-disc and discsynergy tests combined with clavulanic acid, and for the detection of carbapenemase-producing isolates the combined disk tests with phenylboronic acid and EDTA and Blue Carba test were used. PCR amplification of ESBL and carbapenemases-encoding genes was used. In total, 45 Gram-negative bacilli were isolated, and Klebsiella pneumoniae and Pseudomonas aeruginosa being the most prevalent. Extensive resistance was verified to ?-lactam antibiotics and resistance to aztreonam, cefepime and cefotaxime was more pronounced in hospital sewage isolates, with statistically significant differences (p<0.05). Multidrug-resistant phenotype was attributed to 33.3% in isolates exclusively from hospital sewage, with a statistically significant difference (p = 0.0025) in relation to the sewage isolates from the WWTP. ?-lactamase genes were found in 35.6% of the bacteria, with blaKPC and blaTEM having the highest occurrences, both in 17.8% of the isolates, and the blaSHV and blaCTX-M genes in 13.3% and 8, 9%. Only in an isolate of Enterobacter cloacae in the treated sewage from WWTP was the blaSHV gene identified, the other isolates carrying the ?-lactamases genes were found in hospital sewage. The data obtained in this study are important considering that in Brazil the hospital sewage can be released in nature in municipal collection network, however, it is believed that such permission favors the dissemination of bacterial multi-resistance, since, the results show high frequency of bacteria carrying antibiotic resistance genes in the hospital sewer studied. Thus, the implementation of treatment of hospital effluents, especially those in tertiary hospitals, and in addition to the treatment of WWTP would prevent the spread of these bacteria in the environment and negatively impact water resources
8

Uso de simbiótico para prevenção de infecções hospitalares em pacientes colonizados e/ou infectados por bacilos Gram-negativos multirresistentes / Use of a symbiotic product to prevent nosocomial infections in patients colonized and/or infected by multi-resistant Gram-negative bacilli.

Mariana Corrêa Coelho Salomão 27 February 2015 (has links)
Nas últimas décadas, a incidência de infecções hospitalares causadas por bactérias Gram-negativas multirresistentes vem crescendo de maneira vertiginosa em todo o mundo, de modo que a Organização Mundial de Saúde (OMS) recentemente reconheceu essas infecções como uma preocupação mundial devido ao seu impacto negativo sobre as taxas de mortalidade intra-hospitalar e dos custos da assistência à saúde, afetando tanto os países desenvolvidos quanto os em desenvolvimento. Atualmente considera-se que o uso racional de antimicrobianos, a higienização das mãos e o isolamento de contato são as principais medidas disponíveis para contenção desse avanço. Porém, elas são apenas parcialmente efetivas e de implementação trabalhosa e onerosa. Assim, considera-se necessário o desenvolvimento de formas mais simples e eficientes para lidar com esse problema. No presente estudo, nos propusemos a avaliar o impacto da administração de um produto simbiótico a pacientes colonizados e/ou infectados por bactérias Gram-negativas multirresistentes sobre a incidência subsequente de infecções hospitalares relacionadas ao trato respiratório e urinário. Trata-se de um ensaio clínico randomizado, duplamente cego, controlado com placebo, cuja intervenção consistiu na administração oral ou enteral diária de 1010 unidades de Lactobacillus bulgaricus e 1010 unidades de Lactobacillus rhamnosus associados a fruto-oligosacarídeos durante 7 dias, a pacientes internados em um hospital terciário, com colonização prévia por bactérias Gram-negativas multirresistentes, demonstrada por meio de cultura seletiva de swab retal. O desfecho primário do estudo foi a incidência de infecção hospitalar posterior à intervenção, que, na análise do tipo intenção de tratar foi 18/48 (37,50%) no grupo experimental e 12/53 (22,64%) no grupo controle (odds ratio ajustado=1,95, IC95%=0,69-5,50, p=0,21). Os desfechos secundários principais, também de acordo com a análise intenção de tratar, foram: o tempo de internação hospitalar; sendo a mediana de 17 dias no grupo controle e 31 dias no grupo experimental (p= 0,07), taxas de óbito; com valores de 3,77% no grupo placebo e 8,33% no grupo simbiótico (odds ratio ajustado = 1,34, IC95%= 0,454,00, p= 0,61) e ocorrência de eventos adversos; 7,55% no grupo que utilizou placebo e 6,25% no grupo sob intervenção (p= 1,00). Os dados obtidos pelo estudo nos levam à conclusão de que o simbiótico estudado demonstrou-se inefetivo na prevenção de infecções hospitalares do trato respiratório e urinário em pacientes colonizados e/ou infectados por bactérias Gram-negativas multirresistentes. / In recent decades the incidence of multidrug resistant Gram-negative nosocomial infections has been dramatically raising in the whole world. The World Health Organization (WHO) recently recognized nosocomial infections as a global concern due to its negative impact on patients, health care workers and health care institutions, affecting developed countries as well as developing ones. They negatively impact in-hospital mortality and healthcare related costs. Antibiotic stewardship, hand hygiene promotion and contact precautions are the main available measures to control such multidrug resistant Gram-negative organisms in hospitals. However, they are only partially effective as well as difficult to be implemented and expensive. Therefore, simpler and more effective actions are thought to be helpful and urgent. In the main study, we propose to analyze the impact of the administration of a symbiotic product on patients colonized and/or infected by Gram-negative multidrug resistant bacteria upon the subsequent incidence of respiratory and urinary tract nosocomial infections. A randomized, double- blinded, placebo controlled, clinical trial was proposed in order to provide oral or enteral daily administration of 1010 units of Lactobacillus bulgaricus and 1010 units of L. rhamnosus associated with fructo-oligosacharide (FOS) during 7 days, to previously colonized patients with multi-resistant Gram-negative bacteria, identified through selective culture of rectal swab, hospitalized in a tertiary-care hospital. The primary outcome was the incidence of nosocomial infections after the intervention, which in the intention to treat analysis was 18/48 (37,50%) in the experimental group versus 12/53 (22,64%) in the control group (adjusted odds ratio= 1,95, IC95%= 0,69-5,50, p=0,21). Secondary outcomes, according to intention to treat analysis, were hospital length of stay: median of 17 days in the control group and 31 days in the symbiotic group (p= 0,07), mortality rates: 3,77% in the placebo group versus 8,33% in the experimental group (adjusted odds ratio = 1,34, IC95%= 0,45 4,00, p= 0,61) and adverse effects: 7,55% in the control group and 6,25% in the intervention group (p= 1,00). The results of this study leads to the conclusion that the studied symbiotic proved to be ineffective to prevent nosocomial respiratory and urinary tract infections in patients colonized and/or infected by Gram-negative multi-resistant bacteria.
9

Uso de simbiótico para prevenção de infecções hospitalares em pacientes colonizados e/ou infectados por bacilos Gram-negativos multirresistentes / Use of a symbiotic product to prevent nosocomial infections in patients colonized and/or infected by multi-resistant Gram-negative bacilli.

Salomão, Mariana Corrêa Coelho 27 February 2015 (has links)
Nas últimas décadas, a incidência de infecções hospitalares causadas por bactérias Gram-negativas multirresistentes vem crescendo de maneira vertiginosa em todo o mundo, de modo que a Organização Mundial de Saúde (OMS) recentemente reconheceu essas infecções como uma preocupação mundial devido ao seu impacto negativo sobre as taxas de mortalidade intra-hospitalar e dos custos da assistência à saúde, afetando tanto os países desenvolvidos quanto os em desenvolvimento. Atualmente considera-se que o uso racional de antimicrobianos, a higienização das mãos e o isolamento de contato são as principais medidas disponíveis para contenção desse avanço. Porém, elas são apenas parcialmente efetivas e de implementação trabalhosa e onerosa. Assim, considera-se necessário o desenvolvimento de formas mais simples e eficientes para lidar com esse problema. No presente estudo, nos propusemos a avaliar o impacto da administração de um produto simbiótico a pacientes colonizados e/ou infectados por bactérias Gram-negativas multirresistentes sobre a incidência subsequente de infecções hospitalares relacionadas ao trato respiratório e urinário. Trata-se de um ensaio clínico randomizado, duplamente cego, controlado com placebo, cuja intervenção consistiu na administração oral ou enteral diária de 1010 unidades de Lactobacillus bulgaricus e 1010 unidades de Lactobacillus rhamnosus associados a fruto-oligosacarídeos durante 7 dias, a pacientes internados em um hospital terciário, com colonização prévia por bactérias Gram-negativas multirresistentes, demonstrada por meio de cultura seletiva de swab retal. O desfecho primário do estudo foi a incidência de infecção hospitalar posterior à intervenção, que, na análise do tipo intenção de tratar foi 18/48 (37,50%) no grupo experimental e 12/53 (22,64%) no grupo controle (odds ratio ajustado=1,95, IC95%=0,69-5,50, p=0,21). Os desfechos secundários principais, também de acordo com a análise intenção de tratar, foram: o tempo de internação hospitalar; sendo a mediana de 17 dias no grupo controle e 31 dias no grupo experimental (p= 0,07), taxas de óbito; com valores de 3,77% no grupo placebo e 8,33% no grupo simbiótico (odds ratio ajustado = 1,34, IC95%= 0,454,00, p= 0,61) e ocorrência de eventos adversos; 7,55% no grupo que utilizou placebo e 6,25% no grupo sob intervenção (p= 1,00). Os dados obtidos pelo estudo nos levam à conclusão de que o simbiótico estudado demonstrou-se inefetivo na prevenção de infecções hospitalares do trato respiratório e urinário em pacientes colonizados e/ou infectados por bactérias Gram-negativas multirresistentes. / In recent decades the incidence of multidrug resistant Gram-negative nosocomial infections has been dramatically raising in the whole world. The World Health Organization (WHO) recently recognized nosocomial infections as a global concern due to its negative impact on patients, health care workers and health care institutions, affecting developed countries as well as developing ones. They negatively impact in-hospital mortality and healthcare related costs. Antibiotic stewardship, hand hygiene promotion and contact precautions are the main available measures to control such multidrug resistant Gram-negative organisms in hospitals. However, they are only partially effective as well as difficult to be implemented and expensive. Therefore, simpler and more effective actions are thought to be helpful and urgent. In the main study, we propose to analyze the impact of the administration of a symbiotic product on patients colonized and/or infected by Gram-negative multidrug resistant bacteria upon the subsequent incidence of respiratory and urinary tract nosocomial infections. A randomized, double- blinded, placebo controlled, clinical trial was proposed in order to provide oral or enteral daily administration of 1010 units of Lactobacillus bulgaricus and 1010 units of L. rhamnosus associated with fructo-oligosacharide (FOS) during 7 days, to previously colonized patients with multi-resistant Gram-negative bacteria, identified through selective culture of rectal swab, hospitalized in a tertiary-care hospital. The primary outcome was the incidence of nosocomial infections after the intervention, which in the intention to treat analysis was 18/48 (37,50%) in the experimental group versus 12/53 (22,64%) in the control group (adjusted odds ratio= 1,95, IC95%= 0,69-5,50, p=0,21). Secondary outcomes, according to intention to treat analysis, were hospital length of stay: median of 17 days in the control group and 31 days in the symbiotic group (p= 0,07), mortality rates: 3,77% in the placebo group versus 8,33% in the experimental group (adjusted odds ratio = 1,34, IC95%= 0,45 4,00, p= 0,61) and adverse effects: 7,55% in the control group and 6,25% in the intervention group (p= 1,00). The results of this study leads to the conclusion that the studied symbiotic proved to be ineffective to prevent nosocomial respiratory and urinary tract infections in patients colonized and/or infected by Gram-negative multi-resistant bacteria.
10

Study The Change Of Blood Enteric Bacterial DNA Load In Patients With Systemic Inflammatory Response Syndrome

Yang, Ming-chieh 12 September 2012 (has links)
Early detection of infection, identification of microorganism, and correct choice of antibiotics are critical in the management of sepsis. Quantitative real-time polymerase chain reaction (RT-PCR) has the potential to improve the timeliness, sensitivity, and accuracy of detecting pathogens. In this study we utilize this method to detect the enteric bacterial counts in the blood from patients with systemic inflammatory response syndrome (SIRS) in the emergency department (ED). The universal primers utilized in RT-PCR are specific for 23S ribosomal DNA (rDNA) and wec F gene. The results show that in SIRS patients with positive culture results from specimen collected within 10 days after presenting to ED, and patients surviving for less than 28 days, the serum bacterial DNA load of enteric Gram negative bacilli is higher. In SIRS patients with shock, patients fulfilling both white blood cell counts and respiratory criteria of SIRS, and patients fulfilling both white blood cell counts and respiratory criteria of SIRS with Acute Physiology and Chronic Health Evaluation II score more than 20, the serum bacterial DNA load of enteric Gram negative bacilli and 28-day mortality are both higher. These results suggest that bacterial translocation may happen in patients with SIRS and may be related to higher mortality in patients with SIRS.

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