Orientador: Carlos Eduardo Vergani / Banca: Ana Lucia Machado / Banca: Wander José da Silva / Resumo: Infecções causadas por bactérias resistentes a antibióticos são consideradas causa principal de mortalidade entre indivíduos imunocomprometidos e aproximadamente 50 % destas infecções tem sido relacionadas ao Staphylococcus aureus resistente à meticilina (MRSA). Estes microrganismos, quando presentes no biofilme das próteses dentarias, podem se dispersar nas secreções salivares e se disseminar pelo trato respiratório, causando pneumonia aspirativa. Assim, o presente estudo comparou a efetividade do hipoclorito de sódio a 1 %, digluconato de clorexidina a 2 % e irradiação por micro-ondas na desinfecção de próteses totais e corpos-de-prova circulares de resina acrílica para base de prótese (10 x 2 mm) contaminados com MRSA. Para isso, 36 próteses totais simuladas e 36 corpos-de-prova circulares foram confeccionados, esterilizados, inoculados com MRSA (107 ufc/mL) e incubados a 37 °C (por 24 e 48 h, respectivamente). Após incubação, próteses totais e corpos-de-prova foram distribuídos em 4 grupos de estudo (n=9): GC - não foi realizado nenhum método de desinfecção; GH - foi realizada a imersão em solução de hipoclorito de sódio a 1 % por 10 min; GCl -foi realizada a imersão em solução de digluconato de clorexidina a 2 % por 10 min; GM - foi realizada a desinfecção por irradiação em forno de micro-ondas a 650 W por 3 min. A efetividade dos procedimentos de desinfecção foi avaliada por meio de quantificação de colônias viáveis e da viabilidade celular. Para a quantificação de colônias viáveis, alíquotas de 25 μL da solução resultante das diluições seriadas (10-3 a 10-6 para GC e 100 a 10-3 para os grupos experimentais) foram semeadas em placas de Petri em duplicata e todas as placas foram incubadas por 48 h a 37 °C. As colônias foram quantificadas em ufc/mL. Para verificar a efetividade da desinfecção por micro-ondas em longo prazo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Infections caused by antibiotic-resistant bacteria have been recognized as a predominant risk factor for mortality in elderly patients and approximately 50 % of these infections have been related to methicillin-resistant Staphylococcus aureus (MRSA). This microorganism, when present in the denture biofilm, can be released into the oral fluids and aspirated into the lower respiratory tract, thus causing infections such as aspiration pneumonia. The present study compared the efficacy of 1 % sodium hypochlorite, 2 % chlorhexidine gluconate, and microwave irradiation in disinfecting simulated complete dentures and circular specimens of acrylic resin denture base material (10 x 2 mm) contaminated with MRSA. Thirty-six dentures and 36 specimens were made, sterilized, inoculated with MRSA (107 cfu/mL), and incubated at 37 °C (for 24 and 48 h, respectively). After incubation, dentures and specimens were divided into 4 groups of study (n=9): PC - positive control, consisting of dentures and specimens not disinfected; HY - soaking in 1 % sodium hypochlorite solution for 10 min; CHL - soaking in 2 % chlorhexidine gluconate solution for 10 min; and MW - irradiating by microwave for 3 min at 650W. The effectiveness of the disinfection procedures was assessed cell viability (quantification of viable cells and XTT reduction method). For quantification procedures, aliquots of suspensions were plated at dilutions (10-3 to 10-6 for PC and 100 to 10-3 for experimental groups) and incubated (37 °C/48 h). Colonies counts (cfu/mL) were quantified. Dentures disinfected were also incubated at 37 °C for 7 days to verify the long-term effectiveness of disinfection. The viability of cells in each group of specimens was evaluated by XTT reduction method. The results showed that all dentures and specimens from the PC groups showed substantial microbial growth. No evidence of microbial growth was observed... (Complete abstract click electronic access below) / Mestre

INTRODUÇÃO: A dermatite atópica (DA) é considerada a principal e mais freqüente manifestação cutânea da atopia, podendo acometer até 20% da população pediátrica mundial. Trata-se de uma doença multifatorial onde agentes infecciosos como S.aureus são relevantes no desencadeamento das crises. OBJETIVOS: (1) Avaliar a taxa de colonização do S.aureus na pele e vestíbulo nasal de pacientes com DA e o seu perfil de sensibilidade a antibióticos (2) Comparar os resultados com a taxa de colonização do vestíbulo nasal dos cuidadores primários (3) Avaliar a associação entre colonização por S.aureus gravidade da doença e hábitos de higiene. MÉTODOS: Foi realizado estudo prospectivo entre dezembro de 2016 a fevereiro de 2017. Foram avaliados aspectos clínicos, epidemiológicos e laboratoriais de crianças com DA em seguimento na unidade de alergia e imunologia do Instituto da Criança da Faculdade de Medicina da Universidade de São Paulo (ICr HCFMUSP). Foram incluídos pacientes que apresentaram DA moderada ou grave, classificados de acordo com o escore de gravidade SCORAD (scoring atopic dermatitis). Foram excluídos pacientes que haviam utilizado antibioticoterapia há menos de 30 dias da inclusão, que apresentavam infecções cutâneas ou utilizavam imunossupressores por via sistêmica. A pesquisa de S.aureus em pacientes foi realizada por meio de coleta de swab em vestíbulo nasal, lesão aguda e crônica dos pacientes com DA e nos cuidadores primários foi realizado swab de vestibulo nasal. RESULTADOS: Foram avaliados 27 pacientes (14M), 18 com DA moderada e 9, grave. O início da doença ocorreu entre 2 e 60 meses de idade (mediana de 12m) e a coleta de swab ocorreu ao 9 anos (mediana, com variação entre 2 e 15 anos). Todos os pacientes apresentaram colonização por S.aureus em pelo menos um local de coleta, sendo a lesão aguda o mais frequente (24/27), seguido do nariz (23/27) e lesão crónica (20/27). Dezenove cuidadores apresentaram S.aureus em vestíbulo nasal. A presença de S.aureus meticilino resistente (MRSA) foi detectada em 9/23 pacientes no vestíbulo nasal, 8/24 na lesão aguda e 6/20 na lesão crônica. Entre os cuidadores 6/19 apresentaram S.aureus MRSA em vestíbulo nasal. Pacientes e cuidadores primários apresentaram semelhança no perfil de sensibilidade a antibióticos (kappa 0,75). A gravidade da doença (SCORAD), não se correlacionou de maneira significante com a taxa de colonização, mas pacientes com escores de prurido mais elevados apresentaram estafilococos MRSA com maior freqüência de maneira estatisticamente significante (p= 0,29). Houve uma elevada taxa de compartilhamento de produtos com destaque: produtos pessoais (17/27) cama (11/27) e toalha (3/27) CONCLUSÃO: S.aureus permanece como uma bactéria bastante presente na pele de quem apresenta dermatite atópica, independentemente do tipo de lesão. A presença de elevadas taxas de S.aureus MRSA é um sinal de alerta para o cuidadoso manejo de pacientes com DA e estratégias que envolvam a orientação com relação as medidas de higiene e cuidado pessoal devem fazer parte do tratamento da dermatite atópica / Atopic dermatitis (AD) is considered the main and most common cutaneous manifestation of atopy, affecting up to 20% of the world pediatric population. It is a multifactorial disease where infectious agents such as S. aureus are relevant in the onset of crises. OBJECTIVES: (1) To evaluate the rate of colonization of S.aureus in the skin and nasal vestibule of patients with AD and its antibiotic susceptibility profile. (2) To compare the results with the nasal vestibular colonization rate of primary caregivers (3 ) Evaluate the association between S.aureus colonization, disease severity and hygiene habits. METHODS: A prospective study was carried out between December 2016 and February 2017. Clinical, epidemiological and laboratory aspects of children with AD were evaluated at the unit of allergy and immunology of the Children\'s Institute of the School of Medicine of the University of São Paulo (ICr HCFMUSP). Patients with moderate or severe AD, classified according to SCORAD (scoring atopic dermatitis) severity score were included. Patients who used antibiotic therapy less than 30 days before inclusion, who had cutaneous infections or who used systemic immunosuppressants were excluded. The study of S.aureus in patients was performed through nasal vestibule swab collection, acute and chronic lesion of patients with AD, and nasal vestibule swabs were performed in primary caregivers. RESULTS: Twenty-seven patients (14M), 18 patients with moderate AD and 9 patients, were diagnosed. The onset of the disease occurred between 2 and 60 months of age (median of 12 m) and swab collection occurred at 9 years (median, Between 2 and 15 years). All patients presented colonization by S.aureus in at least one collection site, with acute lesion being the most frequent (24/27), followed by the nose (23/27) and chronic lesion (20/27). Nineteen caregivers presented S .aureus in the nasal vestibule. The presence of methicillin-resistant S.aureus (MRSA) was detected in 9/23 patients in the nasal vestibule, 8/24 in the acute lesion and 6/20 in the chronic lesion. Carriers 6/19 presented S.aureus MRSA in the nasal vestibule. Patients and primary caregivers presented similarity in the sensitivity profile to antibiotics (kappa 0.75). The severity of the disease (SCORAD) did not correlate significantly with the rate of colonization, but patients with higher pruritus scores had statistically more significant MRSA staphylococci (p = 0.29). There was a high rate of product sharing with emphasis on: personal products (17/27) bed (11/27) and towel (3/27) CONCLUSION: S.aureus remains a very present bacterium in the skin of those with atopic dermatitis , Regardless of the type of injury. The presence of high rates of S.aureus MRSA are a warning sign for the careful management of patients with AD and strategies that involve guidance regarding hygiene measures and personal care should be part of the treatment of atopic dermatitis

INTRODUÇÃO: A dermatite atópica (DA) é considerada a principal e mais freqüente manifestação cutânea da atopia, podendo acometer até 20% da população pediátrica mundial. Trata-se de uma doença multifatorial onde agentes infecciosos como S.aureus são relevantes no desencadeamento das crises. OBJETIVOS: (1) Avaliar a taxa de colonização do S.aureus na pele e vestíbulo nasal de pacientes com DA e o seu perfil de sensibilidade a antibióticos (2) Comparar os resultados com a taxa de colonização do vestíbulo nasal dos cuidadores primários (3) Avaliar a associação entre colonização por S.aureus gravidade da doença e hábitos de higiene. MÉTODOS: Foi realizado estudo prospectivo entre dezembro de 2016 a fevereiro de 2017. Foram avaliados aspectos clínicos, epidemiológicos e laboratoriais de crianças com DA em seguimento na unidade de alergia e imunologia do Instituto da Criança da Faculdade de Medicina da Universidade de São Paulo (ICr HCFMUSP). Foram incluídos pacientes que apresentaram DA moderada ou grave, classificados de acordo com o escore de gravidade SCORAD (scoring atopic dermatitis). Foram excluídos pacientes que haviam utilizado antibioticoterapia há menos de 30 dias da inclusão, que apresentavam infecções cutâneas ou utilizavam imunossupressores por via sistêmica. A pesquisa de S.aureus em pacientes foi realizada por meio de coleta de swab em vestíbulo nasal, lesão aguda e crônica dos pacientes com DA e nos cuidadores primários foi realizado swab de vestibulo nasal. RESULTADOS: Foram avaliados 27 pacientes (14M), 18 com DA moderada e 9, grave. O início da doença ocorreu entre 2 e 60 meses de idade (mediana de 12m) e a coleta de swab ocorreu ao 9 anos (mediana, com variação entre 2 e 15 anos). Todos os pacientes apresentaram colonização por S.aureus em pelo menos um local de coleta, sendo a lesão aguda o mais frequente (24/27), seguido do nariz (23/27) e lesão crónica (20/27). Dezenove cuidadores apresentaram S.aureus em vestíbulo nasal. A presença de S.aureus meticilino resistente (MRSA) foi detectada em 9/23 pacientes no vestíbulo nasal, 8/24 na lesão aguda e 6/20 na lesão crônica. Entre os cuidadores 6/19 apresentaram S.aureus MRSA em vestíbulo nasal. Pacientes e cuidadores primários apresentaram semelhança no perfil de sensibilidade a antibióticos (kappa 0,75). A gravidade da doença (SCORAD), não se correlacionou de maneira significante com a taxa de colonização, mas pacientes com escores de prurido mais elevados apresentaram estafilococos MRSA com maior freqüência de maneira estatisticamente significante (p= 0,29). Houve uma elevada taxa de compartilhamento de produtos com destaque: produtos pessoais (17/27) cama (11/27) e toalha (3/27) CONCLUSÃO: S.aureus permanece como uma bactéria bastante presente na pele de quem apresenta dermatite atópica, independentemente do tipo de lesão. A presença de elevadas taxas de S.aureus MRSA é um sinal de alerta para o cuidadoso manejo de pacientes com DA e estratégias que envolvam a orientação com relação as medidas de higiene e cuidado pessoal devem fazer parte do tratamento da dermatite atópica / Atopic dermatitis (AD) is considered the main and most common cutaneous manifestation of atopy, affecting up to 20% of the world pediatric population. It is a multifactorial disease where infectious agents such as S. aureus are relevant in the onset of crises. OBJECTIVES: (1) To evaluate the rate of colonization of S.aureus in the skin and nasal vestibule of patients with AD and its antibiotic susceptibility profile. (2) To compare the results with the nasal vestibular colonization rate of primary caregivers (3 ) Evaluate the association between S.aureus colonization, disease severity and hygiene habits. METHODS: A prospective study was carried out between December 2016 and February 2017. Clinical, epidemiological and laboratory aspects of children with AD were evaluated at the unit of allergy and immunology of the Children\'s Institute of the School of Medicine of the University of São Paulo (ICr HCFMUSP). Patients with moderate or severe AD, classified according to SCORAD (scoring atopic dermatitis) severity score were included. Patients who used antibiotic therapy less than 30 days before inclusion, who had cutaneous infections or who used systemic immunosuppressants were excluded. The study of S.aureus in patients was performed through nasal vestibule swab collection, acute and chronic lesion of patients with AD, and nasal vestibule swabs were performed in primary caregivers. RESULTS: Twenty-seven patients (14M), 18 patients with moderate AD and 9 patients, were diagnosed. The onset of the disease occurred between 2 and 60 months of age (median of 12 m) and swab collection occurred at 9 years (median, Between 2 and 15 years). All patients presented colonization by S.aureus in at least one collection site, with acute lesion being the most frequent (24/27), followed by the nose (23/27) and chronic lesion (20/27). Nineteen caregivers presented S .aureus in the nasal vestibule. The presence of methicillin-resistant S.aureus (MRSA) was detected in 9/23 patients in the nasal vestibule, 8/24 in the acute lesion and 6/20 in the chronic lesion. Carriers 6/19 presented S.aureus MRSA in the nasal vestibule. Patients and primary caregivers presented similarity in the sensitivity profile to antibiotics (kappa 0.75). The severity of the disease (SCORAD) did not correlate significantly with the rate of colonization, but patients with higher pruritus scores had statistically more significant MRSA staphylococci (p = 0.29). There was a high rate of product sharing with emphasis on: personal products (17/27) bed (11/27) and towel (3/27) CONCLUSION: S.aureus remains a very present bacterium in the skin of those with atopic dermatitis , Regardless of the type of injury. The presence of high rates of S.aureus MRSA are a warning sign for the careful management of patients with AD and strategies that involve guidance regarding hygiene measures and personal care should be part of the treatment of atopic dermatitis

Seventy-four methicillin-resistant Staphylococcus aureus (MRSA) from two Malaysian hospitals were characterised by both phenotypic and genotypic techniques. These isolates were collected over an 18 year time period in the years, 1982, 1989, 1994 and 2000. All of the Malaysian MRSA isolates were found to be multiresistant and resistant to at least five different antimicrobial agents. Over 30% of them were non-typable by the International Basic Set of bacteriophages. The majority of the typable isolates were susceptible to the group III phages, especially phage 85. The majority of the isolates carried one to six plasmids. Only two isolates were plasmid free. The plasmid profiles of these isolates, other than the 1982 isolates, were very similar to each other. Contour-clamped homogeneous electric field (CHEF) gel electrophoresis was used to examine the genetic relatedness of the isolates. Twenty-six CHEF patterns were found among the isolates. These CHEF patterns were closely related to each other. The predominant CHEF pattern A was found in the 1982, 1989 and 1994 isolates. The CHEF patterns of the year 2000 isolates were different to CHEF pattern A, but still closely related. All of the isolates were found to carry the Allotype III SCCmec and have coagulase-gene type 24. Multilocus sequence typing was preformed on the isolates with CHEF pattern A collected in different years. These isolates were found to have either sequence type 239 (ST239), or its single locus variant. The predominant Malaysian clone belongs to the pandemic clone ST239-MRSA-III that is pandemic in Asian countries. (Enright, 2003, Ko et al., 2005). / A 1.5 kb cryptic plasmid found in Malaysian isolates was indistinguishable from a cryptic plasmid found in an Australian isolate. A 3.0 kb cryptic plasmid found in Malaysian isolates was undistinguishable from a 3.0 kb plasmid found in Singaporean isolates. Class II multiresistance plasmids of 28, 30.5 and 35 kb were commonly found together in many Malaysian MRSA isolates. Both the 28 and 30.5 kb plasmids encode resistance to the heavy-metals and nucleic acid-binding (NAB) compounds. The 35 kb plasmid carries heavy-metal and NAB resistance but also encodes β-lactamase. Structurally these three plasmids are almost identical and probably have the same origin. The differences observed between these plasmids is probably due to excision or partial deletion of the β-lactamase transposon of the original plasmid. The 28 kb plasmid is identical to the 28 kb plasmid of Singaporean and some Australian isolates. A 20 kb plasmid in Indonesian isolates was found to be closely related to these three plasmids. A conjugative plasmid, pWBG707, conferring trimethoprim-resistance was found in Malaysian isolates. It did not carry either of the two staphylococcal trimethoprim-resistance genes, dfrA and dfrD. (Lyon and Skurray, 1987, Dale et al., 1995b) It either encodes a novel resistance gene or the recently discovered dfrG gene. (Sekiguchi et al., 2005) pWBG707 was also found to mobilise a small 3.0 kb kanamycin-resistance plasmid during conjugation. / The mecR1 and mecI genes regulating the transcription of the methicillin-resistance gene, mecA, were also examined in the isolates. The Malaysian isolate, WBG7422, with the predominant CHEF pattern A has a nonsense mutation in its mecI gene that disables it. However, its mecR1 gene is intact. The eastern Australia MRSA (EA MRSA), WBG525, has a CHEF pattern that is closely related to the Malaysian predominant CHEF pattern A and its mecI gene has a mutation identical to the Malaysian isolate. Unlike the Malaysian isolate however, its mecR1 gene has a 166 bp deletion. Both WBG7422 and WBG525 express Class III heterogeneous methicillin resistance. However, WBG525 has more highly resistant cell in its population than WBG7422. The loss of aminoglycoside resistance, together with c. 114 kb of chromosomal DNA, was observed in some Malaysian isolates. The deleted segment was found to carry the aacA-aphD gene that encodes a bifunctional aminoglycoside-modifying enzyme conferring resistance to many of the aminoglycosides. The Malaysian isolates were compared with MRSA from different countries. These MRSA included 18 epidemic MRSA (EMRSA) from the United Kingdom, 15 Australian nosocomial MRSA, five classical MRSA, 22 community-acquired MRSA (CMRSA) from Australia and New Zealand and 46 nosocomial MRSAs from eight Asian-Pacific countries and South Africa. These Asian-Pacific countries were Australia, PR China, Hong Kong, Indonesia, Japan, Philippines, Singapore and Taiwan. / The CHEF patterns of most of the Asian-Pacific and South African isolates were closely related to the Malaysian isolates. Isolates from Singapore, Indonesia and Philippines were found to have an identical CHEF pattern to the Malaysian CHEF patterns A5. The Asian-Pacific and South African isolates, including the Malaysian isolates, were found to be closely related to EMRSA-1, -4 and -7. These EMRSA belong to the ST239-MRSA-III clone and are coagulase-gene type 24. The isolates from Japan were the only Asian-Pacific isolates not related to the other Asian-Pacific isolates and EMRSAs. EMRSA-1 and EA MRSA have the same 166 bp deletion in their mecR1 gene. Both of these strains have closely related CHEF patterns, the same sequence type, coagulase-gene type and SCCmec. These results indicate that these two strains belongs to the same clone and confirms the international spread of this clone in the early 1980s. However, the Malaysian isolates have CHEF patterns that are more closely related to EMRSA-4 than to EMRSA-1. Similar to the Malaysian isolates EMRSA-4 has an intact mecR1 gene. The CMRSA isolates were not related to any of the nosocomial MRSA. They also have very diverse genetic backgrounds but carry less diverse SCCmec allotypes. Most of the CMRSA carry either Allotype IV or V SCCmec These results show that the spread of Malaysian MRSA is due to a single clonal expansion. Infection control measures would have to have been more efficient if this clone was to have been contained. The Malaysian epidemic clone is the Asian pandemic clone, ST239-MRSA-III. The Malaysian isolates and EMRSA-4 probably share the same ancestor. / The presence of the same MRSA strain in Malaysian hospitals and in the hospitals of neighbouring countries indicates that the inter-hospital spread of an epidemic MRSA has occurred. This observation also suggests that the infection control measures in Malaysian hospitals have not been totally effective. The ineffectiveness of infection control has left Malaysian hospitals vulnerable to the future importation of new pandemic clones and/or highly virulent or resistant clones.

Abstract not available

A large part of the antibiotics consumed ends up in wastewater, and in the wastewater the antibiotics may exert selective pressure for or maintain resistance among microorganisms. Antibiotic resistant bacteria and genes encoding antibiotic resistance are commonly detected in wastewater, often at higher rates and concentrations compared to surface water. Wastewater can also provide favourable conditions for the growth of a diverse bacterial community, which constitutes a basis for the selection and spread of antibiotic resistance. Therefore, wastewater treatment plants have been suggested to play a role in the dissemination and development of antibiotic resistant bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) is a large problem worldwide as a nosocomial pathogen, but knowledge is limited about occurrence in non-clinical environments, such as wastewater, and what role wastewater plays in dissemination and development of MRSA.   In this thesis we investigated the occurrence of MRSA in a full-scale wastewater treatment plant (WWTP). We also investigated the concentration of genes encoding resistance to aminoglycosides (aac(6’)-Ie+aph(2’’)), β-lactam antibiotics (mecA) and tetracyclines (tetA and tetB) in three wastewater-associated environments: (1) soil from an overland flow area treating landfill leachates, (2) biofilm from a municipal wastewater treatment plant, and (3) sludge from a hospital wastewater pipeline. In addition, concentrations of mecA, tetA and tetB were investigated over the treatment process in the WWTP. These investigations were performed to determine how the prevalence and concentration of MRSA and the antibiotic resistence genes are affected in wastewater and wastewater treatment processes over time. The occurrence of MRSA was investigated by cultivation and a commercially available real-time PCR assay. In order to determine concentrations of the genes aac(6’)-Ie+aph(2’’), mecA, tetA and tetB in wastewater we developed a LUXTM real-time PCR assay for each gene.   Using cultivation and real-time PCR we could for the first time describe the occurrence of MRSA in wastewater and show that it had a stable occurrence over time in a WWTP. MRSA could mainly be detected in the early treatment steps in the WWTP, and the wastewater treatment process reduced the number and diversity of cultivated MRSA. However, our results also indicate that the treatment process selects for strains with more extensive resistance and possibly higher virulence. The isolated wastewater MRSA strains were shown to have a close genetic relationship to clinical isolates, and no specific wastewater lineages could be detected, indicating that they are a reflection of carriage in the community. Taken together, these data indicate that wastewater may be a potential reservoir for MRSA and that MRSA are more prevalent in wastewater than was previously thought.   The real-time PCR assays, for aac(6’)-Ie+aph(2’’), mecA, tetA, and tetB that we developed, were shown to be sensitive, fast, and reproducible methods for detection and quantification of these genes in wastewater environments. The highest concentrations of all genes were observed in the hospital pipeline, and the lowest in the overland flow system, with tetA and aac(6´)-Ie+aph(2´´) detected in all three environments. In the full-scale WWTP, we continuously detected mecA, tetA and tetB over the treatment process and over time. In addition, it was shown that the treatment process reduces concentrations of all three genes. The data presented in this thesis also indicate that the reduction for all three genes may be connected to the removal of biomass, and in the reduction of tetA and tetB, sedimentation and precipitation appear to play an important role.

The dissertation investigates the S. aureus carriage cases in Vilnius adult population. The aim of the study – to determine the extent of S. aureus carriage of selected adult population and hospitalized patients in Vilnius and evaluate potential risk factors of its carriage as well as antimicrobial resistance of isolated strains and, prevailing genetic elements of the resistance and virulence. It was found that more S. aureus carriers detected in the community group than in hospitalized patients group. Greater isolated S. aureus strains resistance to antibiotics has been found in hospitalized patients group. Methicillin-resistant S. aureus were not isolated in the community group. Greater part of isolated S. aureus strains in community group was susceptible to all analyzed antimicrobial drugs. S. aureus strains resistant to erythromycin and clindamycin contained different genes in studied groups’: ermC dominated in community group, ermA – in hospitalized patients group. In terms of the incidence of tetracycline resistance genes in isolated S. aureus strains, tetK genes were dominant in MSSA and MRSA in both community and hospitalized patients groups. Our results demonstrate that PVL-positive S. aureus strains were more commonly isolated from community than from hospitalized patients group. 15% of spa types circulated in both studied groups. The spa types t4995 – t4999, t5001 – t5005 detected in this study were added into the Ridom StaphTypeTM database. Lithuania currently is... [to full text] / Disertacijoje nagrinėjama S. aureus nešiojimo atvejai suaugusiųjų populiacijoje Vilniaus mieste. Darbo tikslas – nustatyti S. aureus nešiojimo mastą pasirinktoje suaugusiųjų populiacijoje visuomenės bei hospitalizuotų ligonių grupėse Vilniaus mieste ir įvertinti S. aureus nešiojimo potencialius rizikos veiksnius, taip pat išskirtų padermių atsparumą kai kurioms antimikrobinėms medžiagoms, pagrindinius atsparumo ir virulentiškumo genetinius elementus. Nustatyta, kad daugiau S. aureus nešiojimo atvejų aptikta visuomenės grupėje nei hospitalizuotų ligonių. Didesnis S. aureus padermių atsparumas tirtiems antibiotikams buvo hospitalizuotų ligonių grupėje. Visuomenės grupėje meticilinui atsparių S. aureus neišskirta. Didesnė S. aureus dalis, išskirta visuomenės grupėje, buvo jautri visiems tirtiems antimikrobiniams vaistams. Atsparumą eritromicinui ir klindamicinui tirtose grupėse kodavo skirtingi genai: visuomenės grupėje vyravo ermC, hospitalizuotų ligonių grupėje – ermA. Atsparumą tetraciklinui koduojantis tetK genas vyravo abiejose tirtose grupėse. Visuomenės grupėje nustatyta daugiau PVL teigiamų S. aureus padermių nei hospitalizuotų ligonių grupėje. Septintadalis nustatytų spa tipų cirkuliuoja tiek visuomenės, tiek hospitalizuotų ligonių grupėse. Šio tyrimo metu spa tipai t4995 – t4999, t5001 – t5005 pirmą kartą nustatyti Lietuvoje ir įtraukti į Ridom StaphTypeTM duomenų bazę. Nustatyta statistiškai reikšminga asociacija tarp viršutinių kvėpavimo takų S. aureus kolonizacijos... [toliau žr. visą tekstą]

Disertacijoje nagrinėjama S. aureus nešiojimo atvejai suaugusiųjų populiacijoje Vilniaus mieste. Darbo tikslas – nustatyti S. aureus nešiojimo mastą pasirinktoje suaugusiųjų populiacijoje visuomenės bei hospitalizuotų ligonių grupėse Vilniaus mieste ir įvertinti S. aureus nešiojimo potencialius rizikos veiksnius, taip pat išskirtų padermių atsparumą kai kurioms antimikrobinėms medžiagoms, pagrindinius atsparumo ir virulentiškumo genetinius elementus. Nustatyta, kad daugiau S. aureus nešiojimo atvejų aptikta visuomenės grupėje nei hospitalizuotų ligonių. Didesnis S. aureus padermių atsparumas tirtiems antibiotikams buvo hospitalizuotų ligonių grupėje. Visuomenės grupėje meticilinui atsparių S. aureus neišskirta. Didesnė S. aureus dalis, išskirta visuomenės grupėje, buvo jautri visiems tirtiems antimikrobiniams vaistams. Atsparumą eritromicinui ir klindamicinui tirtose grupėse kodavo skirtingi genai: visuomenės grupėje vyravo ermC, hospitalizuotų ligonių grupėje – ermA. Atsparumą tetraciklinui koduojantis tetK genas vyravo abiejose tirtose grupėse. Visuomenės grupėje nustatyta daugiau PVL teigiamų S. aureus padermių nei hospitalizuotų ligonių grupėje. Septintadalis nustatytų spa tipų cirkuliuoja tiek visuomenės, tiek hospitalizuotų ligonių grupėse. Šio tyrimo metu spa tipai t4995 – t4999, t5001 – t5005 pirmą kartą nustatyti Lietuvoje ir įtraukti į Ridom StaphTypeTM duomenų bazę. Nustatyta statistiškai reikšminga asociacija tarp viršutinių kvėpavimo takų S. aureus kolonizacijos... [toliau žr. visą tekstą] / The dissertation investigates the S. aureus carriage cases in Vilnius adult population. The aim of the study – to determine the extent of S. aureus carriage of selected adult population and hospitalized patients in Vilnius and evaluate potential risk factors of its carriage as well as antimicrobial resistance of isolated strains and, prevailing genetic elements of the resistance and virulence. It was found that more S. aureus carriers detected in the community group than in hospitalized patients group. Greater isolated S. aureus strains resistance to antibiotics has been found in hospitalized patients group. Methicillin-resistant S. aureus were not isolated in the community group. Greater part of isolated S. aureus strains in community group was susceptible to all analyzed antimicrobial drugs. S. aureus strains resistant to erythromycin and clindamycin contained different genes in studied groups’: ermC dominated in community group, ermA – in hospitalized patients group. In terms of the incidence of tetracycline resistance genes in isolated S. aureus strains, tetK genes were dominant in MSSA and MRSA in both community and hospitalized patients groups. Our results demonstrate that PVL-positive S. aureus strains were more commonly isolated from community than from hospitalized patients group. 15% of spa types circulated in both studied groups. The spa types t4995 – t4999, t5001 – t5005 detected in this study were added into the Ridom StaphTypeTM database. Lithuania currently is... [to full text]

The rate at which bacterial pathogens are becoming resistant to antibiotics is quite alarming, and therefore much attention has been focussed on this area. The mechanism whereby the bacterial cells acquire resistance is studied in order to determine how this process works as well as to determine if any future resistance mechanisms can be circumvented. In this study three different genera and the antibiotics that are resistant to them were used, namely, penicillin resistant Streptococcus, vancomycin resistant Enterococcus and methicillin resistant Staphylococcus. The results prove that the active sites SXXK, SXN and KT(S) G in the penicillin resistance Streptococcus plays a major role in resistance. It is seen in this study that the SXXK active site is found in all the resistant and most of the intermediate strains, therefore proving to be an important component of the cell wall resistance. It was subsequently noticed the greater the number of mutations found in the sequences the higher the resistance. Three dimensional structures showed the actives sites and their binding pockets. The results also show the change in conformation with a mutation in the active site. The results also proved that the Penicillin Binding Protein (PBP) genes essential for resistance are PBP Ia, PBP 2b and PBP 2x. The results obtained, for the vancomycin resistance in Enterococcus study, proved that the VanC and VanE cluster are very much alike and VanE could have evolved from VanC. There is also close similarity between the different ligase genes. The VanX 3D structure shows the position of the critical amino acids responsible for the breakdown of the D-Ala-D-Ala precursors, and the VanA ligase 3D structure shows the amino acids responsible the ligation of the D-Ala-D-Lac precursors. The analysis performed on the methicillin resistance in Staphylococcus study showed that the genes used to confer resistance are very similar between different strains as well as different species. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Dissertation (Ph.D.)--University of South Florida, 2006. / Title from PDF of title page. Document formatted into pages; contains 117 pages. Includes vita. Includes bibliographical references.