Thesis (MAppSc)--University of South Australia, 2001.

Foodborne diseases caused by non-typhoidal Salmonella represent an important public health problem worldwide (Zhao et al., 2003). The transmission of Salmonella between animals and humans has been well established in epidemiological studies. In the case of complicated illness caused by Salmonella where antibiotics need to be administered, treatment can be compromised if the infecting organism is resistant to the prescribed antimicrobial agent. This study and earlier studies have shown that many Salmonella carry temperate bacteriophages as lysogens. Many of these bacteriophages are capable of mediating generalised transduction (Schicklmaier and Schmieger, 1995; Schicklmaier et al., 1998; Mmolawa et al., 2002). Schmieger and Schicklmaier (1999) demonstrated that bacteriophages ES18 and PDT17 are capable of transduction of antibiotic resistance genes from DT104. Phage-mediated transduction of antibiotic resistance genes has been largely neglected in the study of genetic transfer of antibiotic resistance in bacteria. This study investigates whether bacteriophages exist in antibiotic resistant Salmonella isolates. Such temperate phages in antibiotic resistant isolates could play a significant role in the transfer of resistance to other species of enteric bacteria, such as E. coli. Molecular epidemiology studies of antibiotic resistance genes were undertaken with Salmonella isolates from chicken, pig and human sources that were subjected to PCR for ampicillin (blaTEM-1), tetracycline (tetA, tetB) and streptomycin (aadA1, aadA2, strA, strB) resistance genes as well as Class 1 integrons. The blaTEM-1 gene was widely detected in isolates from pigs and chickens but rarely detected in human isolates. The tetB gene was more commonly found in pig isolates, while the tetA gene was associated with tetracycline resistance in chicken isolates. The strA and strB genes were responsible for streptomycin resistance in the S. Typhimurium isolates while the aadA1 gene was commonly detected in S. Kiambu and S. Virchow isolates. The aadA2 gene was associated with streptomycin resistance in the S. Ohio isolates from pigs. Class 1 integrons were widely distributed across serovars tested from chicken, pig and human sources. Temperate bacteriophages were induced using mitomycin C from antibiotic resistant Salmonella. These phages were able to infect antibiotic-sensitive Salmonella isolates from humans. Bacteriophages induced from one S. Sofia isolate also plaqued on Shigella flexneri. Bacteriophages induced from one S.Kiambu isolate and S. Typhimurium DB21 with an inserted Tn10 transposon (S. Typhimurium DB21 Tn10) were capable of transducing ampicillin and tetracycline resistance, respectively into S. Enteritidis PT1 isolates by in vitro methods. The molecular basis for resistance was established in subsequent PCR for antibiotic resistance genes in donor and recipient strains. This finding, in particular in the wild-type S. Kiambu strain, indicates that Salmonella from a natural source are able to infect and transfer antibiotic resistance by generalised transduction in controlled laboratory experiments. This current study has investigated the transfer of tetracycline and ampicillin resistance from a wild-type Salmonella strain and a laboratory strain of Salmonella to wild-type Salmonella bacteria as it occurs within the normal flora of the chicken gastrointestinal tract. It was demonstrated that the genetic transfer of tetracycline and ampicillin resistance genes as well as Class 1 integrons can occur within the chicken gastrointestinal tract. Transfer of tetracycline and ampicillin resistance could be demonstrated both in vitro and by using bacteriophage lysates obtained from in vivo studies in transduction experiments. It was clearly shown that bacteriophage isolated from chicken faeces and caeca could infect antibiotic sensitive recipient Salmonella. Interaction between phages of the administered Salmonella strains may be occuring with phages of bacteria in the normal flora allowing previously inactive phage in the indigenous flora to plaque on indicator strains. Additionally, strong evidence was presented to suggest that the environment of the chicken gastrointestinal tract could mediate phage type conversion in recipient and transductant strains. Phage typing of these recipient and transductant strains demonstrated a trend for recipient strains to become more resistant to phages in the S. Enteritidis typing panel. This led to weakened phage reactions such RDNC (reaction does not conform) and untypable. The acquisition of phages may be a way for Salmonella to enhance competitive fitness and generate new strains in order to evolve and diversify. Or the acquisition of plasmids either by transduction or conjugation may also mediate phage type conversion. MLVA typing was performed on selected recipient, donor and transductant strains. The changes to tandem repeat loci in Salmonella isolates that have passed through a chicken gastrointestinal tract have not been described before. The changes to fragment length suggest that the bacterial chromosome is undergoing rearrangement; this may be attributed to a number of factors including acquisition of phages, prophage integration into tRNA sites, slipped-strand mispairing or the adaption to changing environment, in this case the chicken gastrointestinal tract. This study has provided molecular epidemiological data on the antibiotic resistance genes and integrons present in Australian Salmonella isolates from human and animal sources. Information on the role of bacteriophages in the transfer of antibiotic resistance genes in vitro and in a chicken gastrointestinal tract has also been established. / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2010

With the spread of antibiotic resistance, alternative treatment methods for bacterial pathogens are needed. Pseudomonas aeruginosa is a Gram negative, opportunistic pathogen that is a common cause of healthcare associated infections and is listed as a critical priority for research and development of treatments by the Centers for Disease Control and Prevention. P. aeruginosa poses an increased risk to patients within the surgical or intensive care unit, patients with indwelling catheters, cystic fibrosis, and burn wound victims. With a paucity of antibiotics in the pipeline for Gram negative bacteria, phage therapy has reemerged as a potential treatment option. Bacteriophages were first discovered in 1917 by Felix d’Herelle, but by the end of World War II, they were all but forgotten in favor of antibiotics. Eastern European countries and the former Soviet Union continued to develop phage therapy since its discovery, but studies were not on par with today’s standards. Recently the idea of phage therapy has reemerged in the Western world due to antibiotic resistance. In vitro and in vivo studies have shown that bacteriophages are easily isolated from the environment, with P. aeruginosa specific phages commonly found in hospital waste water and in sewage. Phage therapy has shown to be very effective at treating planktonic and biofilm forms of antibiotic resistant P. aeruginosa in vitro and in vivo. In humans, clinical trials are limited but phage therapy has successfully treated chronic otitis infections caused by P. aeruginosa and other studies have demonstrated the safety of phage therapy, reporting mild, if any, adverse effects. Bacteriophages may also synergize with several antibiotics, suggesting it may be beneficial to use them in conjunction to treat difficult or chronic infections. Additionally, P. aeruginosa bacteriophages may be beneficial in prophylactic treatment as well. When phages were combined with chlorine, a significant decrease in P. aeruginosa counts in chronic biofilms was observed, while also reducing its ability to form new biofilms. Similar results were noted when phages were applied to the lumen of catheters. These early results are promising for the future, but there are many steps that must be taken before starting new clinical trials and the widespread use of phage therapy begins.

Persister cells are able to survive in the presence of high concentrations of antibiotic, and re-grow once the antibiotic has been removed. Unlike conventional antibiotic resistance, the antibiotic tolerance of persister cells is due to phenotypic switching, and is non-inherited. There is growing evidence for a role of persisters in various persistent bacterial diseases. Burkholderia pseudomallei is a pathogen which causes melioidosis, which often persists in the host despite antibiotic treatment. As persister cells may contribute to persistent melioidosis, this study investigated persisters in B. thailandensis, as a model for B. pseudomallei. Treatment of B. thailandensis with ceftazidime, ciprofloxacin, imipenem or trimethoprim demonstrated persister cells which survived antibiotic treatment. Persister frequencies were increased in the absence of oxygen, and higher in stationary phase cultures compared with growing cultures. Drug concentration did not affect persister frequencies, and inherited antibiotic resistance was not detected. Different persister fractions were detected using treatment with multiple antibiotics, indicating heterogeneous susceptibility to antibiotics. In order to increase understanding of the molecular basis of B. thailandensis persister cells, a transposon mutagenesis-based sequencing approach was used on persister cultures. This indicated some issues with genome coverage and mutant diversity. Genes were identified from mutants present before and/or after ciprofloxacin treatment. In order to try to eradicate persister cells from a culture, two anti-persister strategies were tested. Itaconate appeared to stimulate growth of B. thailandensis, increasing susceptibility to the antibiotic ceftazidime. However, the overall effect of the combination was no greater than ceftazidime alone in the conditions tested. Metronidazole was effective against a persister culture under anaerobic conditions, suggesting it may be useful in treating anaerobic persisters. Treatment of B. pseudomallei infected mice with metronidazole and ceftazidime did not improve survival over ceftazidime treatment alone.

No description available.

Submitted by Elisângela de Albuquerque Sobreira (elilage.vet@gmail.com) on 2018-09-01T12:05:44Z No. of bitstreams: 1 teseELISANGELA2018Selvagens.pdf: 2408013 bytes, checksum: 0ad297624228dce75a585251008d7c5b (MD5) / Approved for entry into archive by Sulamita Selma C Colnago null (sulamita@btu.unesp.br) on 2018-09-03T17:30:58Z (GMT) No. of bitstreams: 1 sobreira_ea_dr_bot.pdf: 2408013 bytes, checksum: 0ad297624228dce75a585251008d7c5b (MD5) / Made available in DSpace on 2018-09-03T17:30:58Z (GMT). No. of bitstreams: 1 sobreira_ea_dr_bot.pdf: 2408013 bytes, checksum: 0ad297624228dce75a585251008d7c5b (MD5) Previous issue date: 2018-08-30 / O Estado de Goiás possui várias áreas de fragmentos florestais urbanos. Este fato, somado à expansão de áreas urbanas não consolidadas, muitas vezes para dentro dos limites de Unidades de Conservação Florestal, permitem um contato permanente e crescente entre os seres humanos e a fauna selvagem, como os macacos-prego. O comportamento imperativo destes animais e a escassez de alimentos em seu habitat peculiar fazem com que estes sejam induzidos pela busca de alimentos, que pode resultar em agressão direta aos visitantes de Parques, tais como mordeduras e arranhões em humanos, tornando-os potenciais disseminadores de micro-organismos patogênicos. O objetivo deste estudo foi caracterizar fenotipicamente micro-organismos isolados da cavidade bucal de 10 primatas Sapajus libidinosus capturados no Parque Ambiental Onofre Quinan, Anápolis-GO. Foram isoladas 111 amostras bacterianas e 12 fúngicas, sendo duas bactérias anaeróbias estritas do gênero Peptostreptococcus, 109 bactérias anaeróbias facultativas e 12 leveduras. Dentre as facultativas, destacaram-se as enterobactérias e os Staphylococcus. Quanto ao teste de antibiograma, foi detectada resistência de enterobactérias aos antimicrobianos tetraciclina e ampicilina, e de Staphylococcus à tetraciclina, eritromicina e clindamicina. As demais cepas apresentaram-se sensíveis aos antimicrobianos testados. A cefoxitina apresentou 100% de eficácia para todas as bactérias.Em casos de mordeduras por macacos-pregos recomenda-se realizar completa higienização nas lesões, as quais devem permanecer abertas, para que possam cicatrizar por segunda intenção. A antibioticoterapia deve ser realizada de acordo com recomendações médicas. / The State of Goiás has several areas of urban forest fragments. This fact, coupled with the expansion of unconstrained urban areas, often within the limits of Forest Conservation Units, allows for a permanent and growing contact between humans and wildlife, such as the monkey-prey. The imperative behavior of these animals and the scarcity of food in their peculiar habitat cause them to be induced by the search for food, which can result in direct aggression to Park visitors, such as bites and scratches on humans, making them potential disseminators of pathogenic micro-organisms. The objective of this study was to phenotypically characterize microorganisms isolated from the oral cavity of 10 Sapajus libidinosus primates captured at the Onofre Quinan Environmental Park, Anápolis-GO. A total of 111 bacterial and 12 fungal samples were isolated, two strict anaerobic bacteria of the genus Peptostreptococcus, 109 facultative anaerobic bacteria and 12 yeasts. Among the facultative ones, enterobacteria and Staphylococcus were highlighted. As for the antibiogram test, resistance of enterobacteria to tetracycline and ampicillin antibiotics was detected, and from Staphylococcus to tetracycline, erythromycin and clindamycin. The other strains were sensitive to the antimicrobials tested. Cefoxitin showed 100% efficacy for all bacteria. In cases of bites by monkey-nails it is recommended to perform complete hygiene on the lesions, which must remain open, so they can heal by second intention. Antibiotic therapy should be performed according to medical recommendations

Orientador: Vidal Haddad Junior / Resumo: O Estado de Goiás possui várias áreas de fragmentos florestais urbanos. Este fato, somado à expansão de áreas urbanas não consolidadas, muitas vezes para dentro dos limites de Unidades de Conservação Florestal, permitem um contato permanente e crescente entre os seres humanos e a fauna selvagem, como os macacos-prego. O comportamento imperativo destes animais e a escassez de alimentos em seu habitat peculiar fazem com que estes sejam induzidos pela busca de alimentos, que pode resultar em agressão direta aos visitantes de Parques, tais como mordeduras e arranhões em humanos, tornando-os potenciais disseminadores de micro-organismos patogênicos. O objetivo deste estudo foi caracterizar fenotipicamente micro-organismos isolados da cavidade bucal de 10 primatas Sapajus libidinosus capturados no Parque Ambiental Onofre Quinan, Anápolis-GO. Foram isoladas 111 amostras bacterianas e 12 fúngicas, sendo duas bactérias anaeróbias estritas do gênero Peptostreptococcus, 109 bactérias anaeróbias facultativas e 12 leveduras. Dentre as facultativas, destacaram-se as enterobactérias e os Staphylococcus. Quanto ao teste de antibiograma, foi detectada resistência de enterobactérias aos antimicrobianos tetraciclina e ampicilina, e de Staphylococcus à tetraciclina, eritromicina e clindamicina. As demais cepas apresentaram-se sensíveis aos antimicrobianos testados. A cefoxitina apresentou 100% de eficácia para todas as bactérias.Em casos de mordeduras por macacos-pregos recomenda-se realizar com... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The State of Goiás has several areas of urban forest fragments. This fact, coupled with the expansion of unconstrained urban areas, often within the limits of Forest Conservation Units, allows for a permanent and growing contact between humans and wildlife, such as the monkey-prey. The imperative behavior of these animals and the scarcity of food in their peculiar habitat cause them to be induced by the search for food, which can result in direct aggression to Park visitors, such as bites and scratches on humans, making them potential disseminators of pathogenic micro-organisms. The objective of this study was to phenotypically characterize microorganisms isolated from the oral cavity of 10 Sapajus libidinosus primates captured at the Onofre Quinan Environmental Park, Anápolis-GO. A total of 111 bacterial and 12 fungal samples were isolated, two strict anaerobic bacteria of the genus Peptostreptococcus, 109 facultative anaerobic bacteria and 12 yeasts. Among the facultative ones, enterobacteria and Staphylococcus were highlighted. As for the antibiogram test, resistance of enterobacteria to tetracycline and ampicillin antibiotics was detected, and from Staphylococcus to tetracycline, erythromycin and clindamycin. The other strains were sensitive to the antimicrobials tested. Cefoxitin showed 100% efficacy for all bacteria. In cases of bites by monkey-nails it is recommended to perform complete hygiene on the lesions, which must remain open, so they can heal by second intentio... (Complete abstract click electronic access below) / Doutor

No description available.

No description available.

Class of 2016 Abstract / Objectives: 1. To compare appropriateness of therapy and the time it takes for appropriate empiric antibiotic therapy to be given from when patients are first admitted for treatment of diabetic foot infection. 2. To compare the time it takes for physicians to “streamline” therapies or switch from empiric antibiotic therapy to specific antibiotics after culture results are obtained 3. To Compare the incidence of readmission within 30 days to the hospital after initial discharge. Methods: In this IRB approved, retrospective study, antibiotic therapy prescribing patterns before and after the distribution of a health network specific empiric antibiotic reference material were compared in patients admitted for diabetic foot infection. Patients were excluded if no antibiotic therapy prescribed, if under the age of 18 years, or if admitted for less than 48 hours (including time spent in the emergency department). The following data were collected and analyzed between the two groups: number of appropriate antibiotic therapy administered, timing of appropriate therapies relative to when appropriate culture samples were obtained if applicable, time it takes to streamline antimicrobial therapy, and the incidence of 30-day readmission. Results: A total of 400 patients were evaluated with 17 pre-intervention and 10 post-intervention patients who meet the inclusion criteria. The pre- and post- intervention groups did not show significant difference in demographics except for comorbid conditions (p=0.055). Overall, there was no significant difference between the pre- and post-intervention group on appropriate empiric therapy given (p=0.382), timing to streamline therapy (p=0.4035), and readmission rates (p=0.401). Conclusions: The health network specific empiric antibiotic recommendations reference material did not influence the timing and appropriateness of empiric antibiotic therapy in treatment of diabetic foot infections and the patient 30-day readmission rates.