Não consta resumo na publicação. / Abstract not available.

Orientadores: Mariangela Ribeiro Resende, Maria Luiza Moretti / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-14T14:58:52Z (GMT). No. of bitstreams: 1 Ferrari_MichelaDeLuca_M.pdf: 2800534 bytes, checksum: 6c0f0dc17633a5c05f98eaf42e330cb7 (MD5) Previous issue date: 2009 / Resumo: Os objetivos do presente estudo foram estimar a prevalência de resistência do M. tuberculosis aos fármacos de primeira linha entre pacientes com tuberculose diagnosticados no Hospital de Clínicas da Unicamp e avaliar o desempenho do método de microdiluição em placa com [3-(4,5-dimethylthiazol-2-yl)- 2,5diphenyl-tetrazolium bromide] (MTT) comparado ao Bactec MGIT 960®. No período foram notificados 360 casos de tuberculose. Destes 211 casos apresentaram cultura positiva para Mycobacterium sp, sendo incluídos 105 casos, nos quais foi identificado o M. tuberculosis. Dentre estes pacientes a apresentação pulmonar da TB ocorreu em 64,8% e co-infecção pelo HIV em 37,1%. A prevalência de resistência a qualquer fármaco foi de 6,7%; multidrogarresistência (RMP e INH) e resistência a INH e SM foram detectadas em 1%, em 3,8% e em 3,8% dos casos, respectivamente. Todos os isolados foram susceptíveis ao EMB. A resistência primária foi encontrada em quatro casos e resistência adquirida em três. Houve associação entre tratamento prévio e resistência (p=0,0181), as demais variáveis estudadas não foram associadas. Dentre os 119 isolados de M. tuberculosis incluídos para a avaliação do desempenho do MTT, ocorreu concordância de 100% para INH e EMB entre os métodos MTT e Bactec MGIT960®, de 99% para RMP (sensibilidade: 90%), enquanto que para SM houve concordância inferior aquela apresentada pelos outros fármacos (95,2%; sensibilidade: 90,9%). A prevalência de resistência entre os casos novos atendidos no Hospital de Clínicas da Unicamp no período de estudo foi de 3,8% para isoniazida, 1% para rifampicina, 3,8% para etambutol e 1% multidrogarresistente. Resistência a qualquer fármaco foi observada em 6,7% dos casos. O método colorimétrico com MTT apresentou bom desempenho e representa uma alternativa acurada, simples e de reduzidos custos, viável e sustentável para locais e países com limitados recursos. / Abstract: This cross-sectional, hospital-based study conducted between January 2006 and March 2008 sought to estimate the resistance of M. tuberculosis to first-line drugs among patients with tuberculosis confirmed by culture at a Brazilian hospital and evaluate the performance of the [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide] (MTT) microplate assay in comparison to the Bactec MGIT 960. During the study period were reported to the surveillance system 360 tuberculosis cases, 211 out of these were confirmed by positive culture for Mycobacterium sp and 105 out of these had M. tuberculosis isolated on culture and were included to the prevalence study. Pulmonary involvement was present in 64.8% of cases and HIV co-infection was found in 37.1%. The prevalence of M. tuberculosis resistance was 6.7%; multidrug-resistance [rifampin (RMP) and isoniazid (INH)] and resistance to INH and streptomycin (SM) were detected in 1%, in 3.8% and in 3.8% of cases, respectively. All isolates were susceptible to ethambutol (EMB). The resistance was primary in four cases and acquired in three cases. Previous treatment was associated with resistance (p=0.0181). Among 119 isolates of M. tuberculosis included to the MMTT performance evaluation, there was 100% observed agreement for INH and EMB between the MTT and Bactec MGIT 960¿ methods. For RMP, the observed agreement was 99% (sensitivity: 90%), and for SM, the level of agreement was lower (95.2%; sensibility 90.9%) than those of the other drugs. The prevalence of M. tuberculosis resistance among the new cases during the study period was 6.7%; multidrug-resistance and resistance to INH and streptomycin (SM) were detected in 1%, in 3.8% and in 3.8% of cases, respectively. The colorimetric method with tetrazolium (MTT) represents an accurate, simple and low cost alternative that is both viable and sustainable for settings with limited resources. / Mestrado / Ciencias Basicas / Mestre em Clinica Medica

Antibiotic resistance is a quickly emerging public health crisis, accounting for more than 700,000 annual global deaths. Global human antibiotic overuse and misuse has significantly expedited the rate at which bacteria become resistant to antibiotics. A renewed focus on discovering new antibiotics is one approach to addressing this crisis. However, it alone cannot solve the problem: historically, the introduction of a new antibiotic has consistently, and at times rapidly, been followed by the appearance and dissemination of resistant bacteria. It is thus crucial to develop strategies to improve how we select and deploy antibiotics so that we can control and prevent the emergence and transmission of antibiotic resistance. Current gold-standard antibiotic susceptibility tests measure bacterial growth, which can take up to 72 hours. However, bacteria exhibit more immediate measurable phenotypes of antibiotic susceptibility, including changes in transcription, after brief antibiotic exposure. In this dissertation I develop a framework for building a paper-based cell-free toehold sensor antibiotic susceptibility test that can detect differential mRNA expression. I also explore how long-term lab evolution experiments can be used to prospectively uncover transcriptional signatures of antibiotic susceptibility. Paper-based cell-free systems provide an opportunity for developing clinically tractable nucleic-acid based diagnostics that are low-cost, rapid, and sensitive. I develop a computational workflow to rapidly and easily design toehold switch sensors, amplification primers, and synthetic RNAs. I develop an experimental workflow, based on existing paper-based cell-free technology, for screening toehold sensors, amplifying bacterial mRNA, and deploying sensors for differential mRNA detection. I combine this work to introduce a paper-based cell-free toehold sensor antibiotic susceptibility test that can detect fluoroquinolone-susceptible E. coli. Next, I describe a methodology for long-term lab evolution and how it can be used to explore the relationship between a phenotype, such as gene expression, and antibiotic resistance acquisition. Using a set of E. coli strains evolved to acquire tetracycline resistance, I explore how each strain's transcriptome changes as resistance increases. Together, this work provides a set of computational and experimental methods that can be used to study the emergence of antibiotic resistance, and improve upon available methods for properly selecting and deploying antibiotics. / 2023-03-17T00:00:00Z

Made available in DSpace on 2016-12-23T13:55:59Z (GMT). No. of bitstreams: 1 Dissertacao mestrado Nazareth Klein.pdf: 9490018 bytes, checksum: a860548b52d0cb66494dd6a26c4306df (MD5) Previous issue date: 2006-10-23 / Este estudo foi conduzido para se avaliar a prevalência e a distribuição das espécies de Candida spp., isoladas de diversos materiais biológicos, obtidos de pacientes internados no Hospital Universitário Cassiano Antonio de Moraes (HUCAM), Vitória-ES, durante o período de janeiro de 2003 a dezembro 2005, e descrever o perfil de suscetibilidade de Candida não-albicans a drogas antifúngicas. A dentificação da espécie Candida albicans foi realizada no meio cromogênico CHROMagar-Candida® e confirmada pela indução positiva de tubo germinativo e/ou clamidoconídeo. A identificação das espécies não-albicans foi realizada pelos seus padrões morfológicos e bioquímicos e pelo sistema comercial API 20 C AUX. O perfil de suscetibilidade às drogas antifúngicas anfotericina B, itraconazol e fluconazol foi estabelecido pelo método de referência, microdiluição em caldo, de acordo com o documento M27-A2 do CLSI, 2002. Estudo comparativo foi realizado, empregandose o método Etest® para as cepas de Candida tropicalis, sendo incluída nesta etapa, a droga voriconazol. Os resultados mostraram 268 isolados de Candida spp., no geral, um predomínio de Candida não-albicans (54%), incluindo C. tropicalis (26%), C. parapsilosis (14%), C. glabrata (10%), C. Krusei (2%), C. guilliermondii (1.5%) e C. lusitaniae (0.5%). Ocorreu uma marcante transição na prevalência de Candida não-albicans, durante os três anos de estudo, oscilando na freqüência de 39% dos isolamentos em 2003 para 74% em 2005. As espécies não-albicans foram mais isoladas de urina (47%), seguido de sangue (39%) e cateter (8%). As maiores ocorrências foram na Unidade de Tratamento Intensivo Geral e Clínica Médica, com 23% em cada setor. A resistência para as espécies não-albicans ao fluconazol foi de 4% e, de suscetível dose-dependente (SDD) ao fluconazol e ao itraconazol foi de 2% e 3%, respectivamente (metodologia CSLI). Com esta metodologia, 98% das cepas de C. tropicalis foram sensíveis ao fluconazol e ao itraconazol, mas 2% foram SDD para estas drogas. Com o método Etest®, 2% dessas cepas foram resistentes (R) a ambas as drogas e 19% foram SDD ao itraconazol. Nenhum isolado de Candida não-albicans foi resistente a anfotericina B ou ao voriconazol. Todos os isolados de Candida albicans foram sensíveis às três drogas analisadas. Em conclusão: a) Houve uma marcante tendência para o isolamento de C. não-albicans no HUCAM, com predomínio de C. tropicalis. b) Observou-se, reduzida suscetibilidade ao fluconazol e ao itraconazol apenas para as espécies C. tropicalis, C. krusei e C. glabrata. c) O método Etest®, usando o meio de ágar Casitone, apresentou ótima concordância com o método de referência para as drogas anfotericina B (100%) e fluconazol (96%), no entanto, para o itraconazol, essa concordância foi de 62%. / This study was carried out to evaluate the prevalence and distribution of the species of Candida spp. Isolated from several biological materials obtained from patients interned at the Hospital Universitário Cassiano Antonio de Moraes (HUCAM), Vitória-ES, during the period of January 2003 to December 2005, and to describe the profile of susceptibility of Candida non-albicans to antifungal drugs. The identification of the species of Candida albicans was made into the chromogenic medium CHROMagar-Candida® and confirmed through the positive induction of a germinative tube and/or clamidoconídeo. The identification of the species nonalbicans was made through of morphologic and biochemical patterns and through the commercial system API 20 C AUX. The profile of susceptibility to the antifungal drugs amphotencin B itraconazole and fluconazole was established by the reference method, broth microdilution, according to the document M27-A2 from CLSI, 2002. A comparative study was conducted, using the method Etest® for the strains of Candida tropicalis being included at this stage, the drug voriconazole. The results showed that 268 isolates of Candida spp. were obtained during the period of the study and, in general, a predominance was observed in the isolation of Candida nonalbicans (54%) at HUCAM, including C. tropicalis (26%), C. parapsilosis (14%), C. glabrata (10%), C. krusei (2%), C. guilliermondii (1.5%) and C. lusitaniae (0.5%). There was a relevant transition in the prevalence of Candida non-albicans during the three years of study, oscillating in the frequency from 39% of the isolations in 2003 to 74% in 2005. The non-albicans species were more isolated from urine (47%), followed by blood (39%) and catheter (8%). The biggest occurrences were noticed in patients interned at the General Intensive Care Unit and Medical Clinic with a rate of 23% in each one. The resistance rate noticed for the non-albicans species to fluconazol was of 4% and, of susceptible dose-dependent (SDD) to fluconazole and to itraconazole was of 2% and 3% respectively (methodology CSLI). With the use of this methodology, it was observed that 98% of the strains of C.tropicalis were sensitive to fluconazole and to itraconazole, but 2% were SDD to these drugs. When the method Etest® was used, 2% of these samples were resistant to both drugs and 19% were SDD to itraconazole. No isolated of Candida non-albicans was resistant to amphotericin B or to voriconazole. All the isolates of Candida albicans were sensitive to the three drugs analyzed. With this study it was concluded that there was a striking tendency to the isolation of C. non-albicans, with the predominance of C. tropicalis. Reduced susceptibility to fluconazole and itraconazole was also noticed only in the species C. tropicalis, C. krusei and C. glabrata, reinforcing the concern about a high number of isolations of these species non-albicans at HUCAM. The Etest® method using the medium of agar Casitone, showed an excellent concordance with the reference method to the drugs amphotericin B (100%) and fluconazole (96%). However, for the itraconazole this agreement was of 62%.

Made available in DSpace on 2016-12-23T13:56:03Z (GMT). No. of bitstreams: 1 Dissertacao - Cynthia.pdf: 1641533 bytes, checksum: 56ac8be8ae2e1e0e55c011b99fe0d3aa (MD5) Previous issue date: 2009-03-20 / Rapidly growing mycobacteria (RGM) can cause a wide spectrum of disseminated or localized diseases, especially pulmonary, skin, or soft tissue infections. In last years infections due to contaminated materials and invasive procedures have been also increasingly reported. Recent outbreaks of infections affecting more than 1000 patients submitted to different invasive procedures in Brazil underscores this issue. Of the RGM, members of the M. chelonae - M. abscessus group are the most pathogenic and antimicrobial resistant. Even with multiple drug combinations, multiresistant RGM infections may be difficult to cure. In this study we describe the molecular identification, typing and in vitro susceptibilities to antimicrobial agents of RGM involved in recent infections in Brazil. The study was carried out in two groups of RGM isolates: one group recovered from different outbreaks (75 isolates) and a second group recovered from sporadic infections (10 isolates). hsp65 and rpoB gene sequencing was used for discrimination between species of M. chelonae - M. abscessus group and pulsed field gel electrophoresis (PFGE) was used to evaluate possible clonal relatedness and diversity among the isolates. Broth microdilution MICs of 15 antimicrobial agents were determined for these clinical isolates. Three species were identified in RGM outbreaks: M. massiliense from video assisted surgeries; M. bolletii from mesotherapy and M. abscessus from liposuction and mammaplasty. Molecular typing by PFGE demonstrated the clonal relatedness within M. massiliense isolates and within M. abscessus isolates. Mesotherapy and pulmonary isolates presented different PFGE patterns. Our results showed that the isolates drug resistance does not differed markedly by PFGE pattern. The resistance rates of these isolates to the currently available agents were high. The majority of M. massiliense isolates was susceptible to clarithromycin, amikacin and tigecyclin, whereas M. bolletii and M. abscessus isolates were susceptible only to amikacin and tigecyclin and moderately susceptible to cefoxitin. In conclusion, despite in vitro drug sensitivity tests limitations, the results provided may be sufficient to guide clinicians in selecting appropriate therapy for RGM infections. / Micobactérias de crescimento rápido (MCR) podem causar um amplo espectro de doenças, desde infecções cutâneas superficiais até doenças disseminadas graves. Relatos de infecções adquiridas devido ao uso de materiais contaminados e a procedimentos cirúrgicos invasivos têm aumentado nos últimos anos. Os surtos ocorridos recentemente no Brasil e que afetaram mais de 1000 pacientes comprovam este fato. Entre as espécies de MCR, aquelas pertencentes ao grupo M. chelonae - M. abscessus são as mais patogênicas e resistentes aos antimicrobianos. Mesmo em vigência de poliquimioterapia, pacientes portadores de infecções causadas por MCR podem não obter cura clínica. Neste estudo, identificamos espécies de MCR envolvidas em surtos e infecções esporádicas no Brasil no período de 2004 a 2008 e analisamos seus perfis genotípicos e de sensibilidade a antimicrobianos. Para isso, realizamos o estudo em dois grupos de MCR: o primeiro constituído por isolados relacionados a surtos (75 isolados) e o segundo por isolados não relacionados a surtos (10 isolados). O seqüenciamento dos genes hsp65 e rpoB foi utilizado para diferenciar entre as espécies do grupo M. chelonae - M. abscessus e a eletroforese em campo pulsátil (PFGE) para avaliar possíveis semelhanças entre os perfis genotípicos. A determinação das concentrações inibitórias mínimas (MIC) de 15 antimicrobianos frente aos isolados de MCR foi determinado pelo método de microdiluição em caldo. A partir dos testes realizados, foram identificadas 3 espécies de MCR relacionadas a surtos: M. massiliense, relacionado a videocirurgias; M. bolletii relacionado a mesoterapia; e M. abscessus, relacionado a cirurgias estéticas. A análise genotípica por PFGE desses isolados permitiu demonstrar ou comprovar a relação clonal entre os isolados de M. massiliense e entre os isolados de M. abscessus. Porém, os isolados provenientes de mesoterapia e infecções esporádicas apresentaram diferentes perfis genotípicos. As espécies analisadas, independentemente de sua origem (surto ou infecção esporádica) apresentaram uma ampla resistência in vitro aos antimicrobianos. Isolados de M. massiliense só apresentaram sensibilidade in vitro à claritromicina, amicacina e tigeciclina, enquanto os isolados de M. bolletii e M. abscessus foram sensíveis somente à amicacina e tigeciclina e moderadamente sensíveis à cefoxitina. Em conclusão, a análise ampla dos perfis genotípicos e, sobretudo de resistência, como efetuado neste trabalho, mesmo com as limitações próprias de um critério fenotípico in vitro, pode auxiliar o médico na fundamentação do esquema terapêutico.

Made available in DSpace on 2016-12-23T13:56:07Z (GMT). No. of bitstreams: 1 Dissertacao Bruna Malacarne.pdf: 2452979 bytes, checksum: bd4d5918bd0a11fc40527e153ad97a3d (MD5) Previous issue date: 2010-12-10 / A frequência de candidemia tem aumentado nas últimas décadas, com crescente ocorrência de espécies não-albicans. Candida tropicalis representa, em geral, a espécie não-albicans mais freqüente no Brasil e pode apresentar crescimento tipo trailing nos testes de microdiluição em caldo, frente a drogas azólicas, o que dificulta e confunde a leitura dos valores de concentração inibitória mínima (CIM). Os objetivos do presente trabalho foram avaliar a ocorrência de candidemia causada por C. tropicalis no Hospital Universitário Cassiano Antônio de Moraes (HUCAM), Vitória Espírito Santo, e seu perfil de suscetibilidade a fluconazol, itraconazol e anfotericina B, conforme metodologia de referência M27-A3 (CLSI, 2008), propor modificações deste teste, além de avaliar a influência de diferentes períodos de incubação e formas de leitura. Isolados de Candida tropicalis (82) testados pelo método referência foram selecionados e submetidos aos testes modificados, como incubação na temperatura de 42°C, adição de Tricostatina A (TSA) e do composto colorimétrico resazurina. Os resultados obtidos nos testes modificados foram avaliados através da determinação das concordâncias categóricas e essenciais com o teste padrão. Os resultados mostraram que no período de 2006 a 2009, a frequência de candidemia no HUCAM variou de 1,21 a 1,65 casos/1.000 admissões hospitalares e de 0,16 a 0,25 casos/1.000 pacientes-dia. C. albicans representou 45% dos episódios, seguida por C. tropicalis (26%), C. parapsilosis (14%), C. glabrata (10%) e outras (C. krusei, C. guilliermondii e C. lusitaniae). Os maiores percentuais de resistência de C. tropicalis a fluconazol e a itraconazol ocorreram com 48 horas de incubação (26% versus 5% e 17% versus 1,2%, respectivamente). Foi observado que 28,05% dos isolados apresentaram crescimento tipo trailing para uma ou para as duas drogas testadas. As concordâncias categóricas e essenciais dos testes modificados, em relação à metodologia padrão, variaram de 70 a 87%, com 24 horas de incubação e para ambas a drogas. Com 48 horas de incubação, as modificações introduzidas (incubação a 42ºC e adição de TSA) propiciaram menores percentagens de concordâncias categóricas e essenciais que o método com adição de resazurina. A incubação a 42°C correlacionou com as melhores concordâncias entre as formas de leitura visual e espectrofotométrica, em comparação com o 9 método padrão. Diferentes perfis de crescimento tipo trailing foram observados, sendo que as três modificações realizadas foram eficazes em reduzir este fenômeno com 24 horas de incubação, mas apenas os métodos a 42ºC e com TSA foram capazes de reduzir o trailing com 48 horas de incubação. A análise de prontuários médicos permitiu verificar que isolado com crescimento tipo trailing apresentou resposta terapêutica satisfatória ao fluconazol e que isolado que permaneceu resistente nos testes modificados não respondeu a tratamento com fluconazol, in vivo / The frequency of candidemia has increased in recent decades, with raising occurrence of non-albicans species. In general, Candida tropicalis is the most frequent non-albicans species in Brazil and may present trailing growth in broth microdilution tests with azole drugs, which complicates and confuses the reading of MIC values. The objectives of this study were evaluate the occurrence of candidemia caused by C. tropicalis in HUCAM and your susceptibility profile with fluconazole, itraconazole and amphotericin B, according to reference methodology M27-A3 (CLSI, 2008) propose modifications in this test, and evaluate the influence of different incubation periods and ways of reading. Isolates of Candida tropicalis were selected and submitted to the modified tests: incubation temperature of 42°C, addition of TSA and colorimetric compound resazurin. The results obtained with modified tests were evaluated through essential and categorical agreements considering the reference methodology. The results showed that in the period of 2006 to 2009, the frequency of candidemia in HUCAM ranged from 1.21 to 1.65 cases / 1,000 admissions and 0.16 to 0.25 cases / 1,000 patient-days. C. albicans accounted for 45% of the episodes, followed by C. tropicalis (26%), C. parapsilosis (14%), C. glabrata (10%) and other ones (C. krusei, C. guilliermondii and C. lusitaniae). The highest percentages of resistance to fluconazole and itraconazole occurred with 48 hours of incubation (26% versus 5% and 17% versus 1.2%, respectively). 28.05% of the isolates showed trailing growth for one or both drugs. The categorical and essential agreements of the modified tests when compared with the standard methodology, ranged from 70 to 87%, with 24 hours of incubation and for both drugs. With 48 hours of incubation, the modifications (incubation at 42°C and addition of TSA) provided smaller percentages of categorical and essential agreements when compared with the addition of resazurin. The best agreement between ways of reading (visual and spectrophotometric) was obtained with the incubation at 42°C, compared with the standard method. Different trailing growth profiles were observed and the three modified methods were effective in reducing this phenomenon with 24 hours of incubation, but only the methods 42°C and TSA were able to reduce it at 48 hour. The analysis of medical records indicated that isolated with trailing growth showed 11 satisfactory therapeutic response to fluconazole and the isolated that remained resistant in the modified tests did not respond to treatment with fluconazole in vivo

Made available in DSpace on 2014-08-20T14:31:27Z (GMT). No. of bitstreams: 1 dissertacao_juliana_nunes_vieira.pdf: 749761 bytes, checksum: d10f921e3d83dd0cb845cc767149a9f3 (MD5) Previous issue date: 2012-03-14 / The rapid development of resistance to gastrointestinal parasites anthelmintics has shown the limited efficiency of this method in the suppression of endoparasitoses in ruminants, and has furthered research in alternative control methods. The use of chemicals in animal anthelmintic treatment, in association with nematophagous fungi used for biological control, is a strategy that has proven to be effective in reducing the nematode population density of farm animals. This study aims to verify the in vitro susceptibility of the nematophagous fungi Arthrobotrys oligospora, Duddingtonia flagrans, Paecilomyces fumosoroseus, Paecilomyces lilacinus, Paecilomyces marquandii and Paecilomyces variotii against the antiparasitic drugs albendazole, thiabendazole, ivermectin (100%), levamisole (7.5%) and closantel (10%) by using the Minimum Inhibitory Concentration (MIC). MICs ranged between 4 and 0,031µg/mL for albendazole, thiabendazole and ivermectin, between 0,937 and 0,117µg/mL for levamisole, and between 0,625 and 0,034 for closantel. The results obtained showed that all antiparasitic drugs tested had an in vitro inhibitory effect on nematophagous fungi, being able to jeopardize the fungus action as a biological control bioagent. / O rápido desenvolvimento de resistência de parasitos do trato gastrintestinal a antihelmínticos tem demonstrado limitada eficiência desse método para o controle de determinadas endoparasitoses em ruminantes, incentivado assim, pesquisas com métodos alternativos de controle parasitário. A utilização de compostos químicos no tratamento anti-helmíntico de animais, em associação com fungos nematófagos usados no controle biológico, é uma estratégia que vem se mostrando eficaz para a redução da densidade populacional de nematódeos nos animais de produção e pouco se sabe sobre seu emprego simultâneo. Este trabalho teve por objetivo verificar, através da Concentração Inibitória Mínima (CIM), a suscetibilidade in vitro dos fungos nematófagos Arthrobotrys oligospora, Duddingtonia flagrans, Paecilomyces fumosoroseus, Paecilomyces lilacinus, Paecilomyces marquandii e Paecilomyces variotii aos antiparasitários albendazol, tiabendazol e ivermectina (100%), levamisol (7,5%) e closantel (10%). As CIMs variaram de 4 a 0,031µg/mL para albendazol, tiabendazol e ivermectina, de 0,937 a 0,117µg/mL para o levamisol e de 0,625 a 0,039µg/mL para o closantel, dependendo do fungo testado. Os resultados mostram que todos os antiparasitários testados tiveram efeito inibitório in vitro sobre os fungos nematófagos, podendo comprometer suas ações como bioagentes de controle biológico.

Negli ultimi decenni l'utilizzo degli antibiotici a scopo terapeutico o come promotori della crescita nell'allevamento animale ha portato alla comparsa e alla diffusione di microrganismi resistenti. In questo contesto, la presenza di Lattobacilli (LAB) antibiotico resistenti non rappresentano di per sé un rischio clinico. Tuttavia la possibilità che essi ma possono essere veicolo di geni codificanti l'antibiotico-resistenza verso batteri patogeni presenti negli alimenti o nel tratto gastro-intestinale umano (inclusi enterococchi, streptococchi e listeria), costituisce un possibile rischio per la salute umana che deve essere attentamente valutato. Obiettivo di questo lavoro è stato quello di valutare attraverso metodi di indagine fenotipica con le tecniche delle microdiluizioni in brodo, Etest e disc-diffusion, i livelli di antibiotico resistenza per le specie S. thermophilus e L. plantarum verso gli antibiotici tetraciclina, eritromicina, clindamicina, streptomicina, gentamicina, ampicillina. Ceppi atipici appartenenti alla specie S. thermophilus sono stati sottoposti ad analisi genetiche con lo scopo di caratterizzare e localizzare i geni responsabili della resistenza. E' stato inoltre testato il possibile trasferimento orizzontale dei geni di antibiotico resistenza nativi da S. thermophilus verso i batteri Gram-positivi E. faecalis e Listeria monocytogenes. In alcuni ceppi di S. thermophilus resistenti si sono infine osservati e studiati particolari caratteri fenotipici ( fitness ) correlati alla presenza delle determinanti genetiche di antibiotico resistenza nell'ospite batterico. / In the last decades, the use of antibiotics in human therapy or in animal husbandry as growth promoters has induced the development and the diffusion in antibiotic resistant micro-organisms. In this context antibiotic resistant Lactic Acid Bacteria (LAB) do not represent a clinical risk in themselves. However, the possibility that S. thermophilus cultures might transfer antibiotic resistance genes to pathogenic species either present in food or in the gastrointestinal tract (including enterococci, streptococci and listeria) represents a potential clinical risk that needs to be carefully evaluated. The aim of this study was to evaluate by means of phenotypic methods (microdilution, E-test, disc-diffusion) the levels of antibiotic resistance for S. thermophilus and L. plantarum species against the antibiotic tetracycline, erythromycin, clyndamicin, streptomycin, gentamycin and ampicillin. The atypical resistant S. thermophilus strains were subjected to genetic analyses in order to characterise and to localise the antibiotic resistance determinants. Furthermore the ability of the resistant S. thermophilus strains in transferring the antibiotic resistant determinant was assessed in mating experiments using as recipients the Gram-positive bacteria E. faecalis and Listeria monocytogenes. In same resistant S. thermophilus strains, special bacterial fitness related with the presence of the antibiotic resistance determinants in the bacterial hosts were observed and studied.

No description available.

Antimicrobial resistance is considered by many prominent researcher and scientist as a profound global health crisis that us humans must face in the next decade. It is threatening the effectiveness of these once-reliable weapons against bacterial infections and leaving us susceptible to pathogenic agents. The indiscriminate overprescription of antibiotic in healthcare and animal husbandry, has led to an increased emergence of “super bugs”— a resistant strain of bacteria that were once susceptible to antibiotic—. The escalating creation of those resistant bacteria has been coupled with a proliferation of research papers that seek to explain the working mechanism of antibiotics and their efficacy on the bacterial pathogens, however these efforts often fall short of explaining the impact that antibiotics has on the bacterial metabolism. This project utilizes an established technology, specifically silicone nano-wire ion-selective field-effect transistor in an innovative approach to discern alteration in the metabolic pathways induced by various antibiotics. The methodology involves measuring extracellular acidity of the tested culture and converting it to an electrical signal to extract valuable information about the metabolic process of the bacteria, and how is altered in the presence of antibiotics. Empirical observations pertaining bacteriostatic antibiotics suggests comprehensive suppression of metabolic pathways, encompassing the efflux transition from acetyl-CoA to acetate, resulting an elevated pH level in cultures treated with bacteriostatic agents relative to their wild-type counterparts. Our experimental data also indicates a shift in bacterial metabolic and physiological responses to bactericidal antibiotic-induced stress which include an increased respiration rate, and a heightened activity of the TCA cycle in the test group with bactericidal antibiotics, causing acetate uptake from the medium and decelerating the acidification of the treated culture compared to the wild-type. The results clearly demonstrate a successful utilization of the chip to further study the effects that antibiotics have on bacteria and the interplay between bacterial metabolism and antibiotic efficacy.