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.

Introdução: A problemática referente à conduta com profissionais na área de saúde colonizados por Staphylococcus aureus sensíveis e resistentes à metilcilina está em grande evidência, por ser este um importante patógeno causador de doenças com alta morbi-mortalidade.(LOWY, 1998). Atualmente as infecções por Staphylococcus aureus não respondem mais ao tratamento com os antimicrobianos anteriormente utilizados (CDC, 2006). O Staphylococcus aureus, resistente à meticilina (MRSA), vem se disseminando nos serviços de saúde e tem sido uma das causas de infecções com maior dificuldade de tratamento (CDC,1999). A maioria das infecções ocorre em pessoas colonizadas com o micro-organismo, sendo o carreador de longo tempo um fator de risco mais fortemente associado com infecção subsequente (WERTHEIM et al, 2005a). Objetivos: Avaliar a colonização e o perfil de susceptibilidade dos Staphylococcus aureus isolados na saliva da equipe de enfermagem atuante nas unidades de terapia intensiva, clínica médica, clínica cirúrgica e gineco-obstétrica de uma instituição de saúde de grande porte do interior paulista. Determinar a prevalência de portadores de Staphylococcus aureus resistentes à meticilina e à mupirocina, levando em consideração o tempo de atuação profissional, jornada no hospital e tempo de contato com os pacientes desse hospital. Métodos: Foram coletadas três amostras da saliva de 351 indivíduos, correspondendo a 94,1% dos profissionais da equipe de enfermagem com intervalo de dois meses entre as coletas. As amostras foram semeadas em agar manitol salgado e colônias típicas de Staphylococcus aureus foram identificadas pela coloração de Gram, produção de catalase, coagulase, Dnase, fermentação do manitol e o perfil de susceptibilidade determinado pelo teste de difusão de disco. Resultados: A prevalência entre os trabalhadores foi de 144 (41,0%) sendo 25 (7,1%) caracterizados como resistentes e 104 (29,6%) como sensíveis à meticilina (MSSA) 15 (4,3%) não foram recuperados para o antibiograma. Os carreadores transitórios representaram 81,2% e os persistentes 18,8%. A resistência à mupirocina foi de 73,1% entre os MRSA e 9,3% nos MSSA. Os resultados evidenciaram que os enfermeiros e técnicos de enfermagem constituem a categoria profissional mais susceptível à colonização por MRSA. O tempo na instituição não teve uma forte correlação com a colonização do profissional, pois trabalhadores com menor tempo na instituição também tiveram alta incidência de colonização. Discussão: Ao considerarmos outros fatores envolvidos como o setor de trabalho, fica evidenciado um panorama de risco para a segurança do paciente. Conclusão: Constatamos, na cavidade bucal, um potencial reservatório e fonte de disseminação de Staphylococcus aureus nos serviços de saúde, bem como um fator de risco de infecção para o trabalhador e, portanto, a necessidade de estudos específicos e intervenções para a prevenção e controle de MRSA, considerando principalmente a condição de setores especiais. / Introduction: The problem of how to manage health professionals colonized by methicillin sensitive and resistant Staphylococcus aureus is very evident, as this important pathogen causes different diseases with high morbidity and mortality rates (LOWY, 1998). Today, infections by Staphylococcus aureus no longer respond to treatment with formerly used antibiotics (CDC, 2006). Methicillin resistant Staphylococcus aureus is spreading across health services and has been one of the infection causes most difficult to treat (CDC, 1999). Most infections affect people colonized by the microorganism. Long-term carriers are a risk factor more strongly associated with subsequent infection (WERTHEIM et al, 2005a). Aims: To assess the colonization and susceptibility profile of Staphylococcus aureus isolated in the saliva of nursing teams active at the intensive care, medical clinic, surgical clinic and gynecological-obstetrical units of a large health institution in the interior of São Paulo State, Brazil. To determine the prevalence of nursing professionals carrying methicillin and mupirocin resistant Staphylococcus aureus, in view of their length of professional activity, work hours at the hospital and time of contact with hospital patients. Methods: Three saliva samples were collected from 351 individuals, corresponding to 94.1% of nursing team professionals, with a two-month interval between the collections. The samples were seeded in mannitol salt agar and typical colonies of S. aureus were identified through Gram stain; catalase, coagulase and Dnase production; mannitol fermentation and susceptibility profile determined by the disk diffusion test. Results: Prevalence levels among workers corresponded to 144 (41,0%) colonized by S aureus, 25 (7,10%) of whom were characterized as MRSA and 104 (29.6%) as methicillin sensitive Staphylococcus aureus, while 15 (4.3%) were not recovered for the antibiogram. Transitory carriers represented 81,2% and persistent carriers 18,8%. Mupirocin resistance was 73.1% among MRSA and 9.3% among MSSA. Results evidenced that nursing technicians and nurses were the professional category most susceptible to MRSA. No strong correlation was found between length of professional activity at the institution and colonization, as professionals working less time at the institution also displayed high colonization ratios. Discussion: These results are relevant for the study institution. When considering other factors involved in professional categorization and the work site, a picture of risk for patient safety is evidenced. Conclusion: Workers\' oral cavity is a potential reservoir and source of dissemination of S. aureus in health services, as well as a risk factor for infection. Hence, specific studies and MRSA prevention and control interventions are needed, mainly when considering the condition of special sectors.

La plasticité génomique de Staphylococcus aureus lui permet d’acquérir des gènes codant des facteurs de virulence mais aussi des gènes de résistance aux antibiotiques, notamment la cassette de résistance à la méticilline (SCCmec). La résistance à la méticilline est d’abord apparue dans des souches hospitalières à l’origine de grands clones pandémiques nosocomiaux, puis a ensuite émergé en milieu communautaire chez des souches virulentes possédant la leucocidine de Panton-Valentine. Nous avons observé en 2002, en milieu hospitalier et communautaire, l’émergence inquiétante de S. aureus résistant à la méticilline (SARM) portant le gène tst de la toxine du choc toxique staphylococcique (TSST-1). Notre travail a consisté à : (i) l’élaboration de nouveaux outils contribuant à la description de clones de SARM, notamment d’un outil de typage de la cassette SCCmec, (ii) la caractérisation phénotypique et moléculaire de ce nouveau clone, (iii) l’étude de l’épidémiologie de ce clone, (iv) l’exploration de la pathogénie de ce clone en recherchant les propriétés génétiques qui lui confèrent une telle virulence et épidémicité, et notamment en identifiant le rôle de la TSST-1. Le clone de SARM tst+ est un clone épidémique de fond génétique ST5 en Multi Locus Sequence yping, atteignant principalement les sujets jeunes, et responsable d’infections variées à la fois toxiniques et suppuratives. Il est doté d’une cassette SCCmec atypique de type I tronquée dont le rôle dans le potentiel épidémique et de virulence de ce clone reste à déterminer. Enfin, la TSST-1 ne semble pas jouer un rôle déterminant, direct ou indirect, dans la pathogénie pléiotropique de ce clone / The plasticity of the Staphylococcus aureus genome confers to this specie the ability to gain accessory genes encoding virulence factors as well as antibiotic resistance determinants such as Staphylococcal cassette chromosome mec SCCmec that encodes methicillin-resistance. Methicillin resistance first emerged in hospital-acquired strains originally of successful nosocomial pandemic clones, and is also risen in virulent community-acquired strains containing the Panton-Valentine leucocidin. In 2002, we observed the worrying emergence of a new methicillin-resistant S. aureus (MRSA) clone that contains the tst gene encoding toxic shock syndrome toxin (TSST-1) responsible for both hospital and community-acquired infections. Our study was focused on: (i) new tools for MRSA description, mainly on a SCCmec typing tool, (ii) the characterisation of this new clone by molecular and phenotypic methods, (iii) the epidemiology of this clone, (iv) the pathogenic potential of this clone and the investigation of the genetic features that enhance transmission and virulence, particularly the role of TSST-1. The tst+ MRSA clone is an epidemic clone of genetic background ST5 by multilocus sequence typing that occurs mainly in young people and is responsible for a wide diversity of clinical syndromes including toxin-mediated and suppurative diseases. This clone harbours a peculiar cassette “truncated SCCmec type I” which could play an important role in virulence and transmission but are still under investigation. TSST-1 does not play a determining role (either directly or indirectly) in the pleiotropic pathogenesis of this clone

O estado de portador de Staphylococcus aureus resistente à meticilina é apontado como preditor de infecção principalmente entre pacientes hospitalizados, bem como fator para a disseminação ambiental e de pessoa a pessoa, incluindo trabalhadores de serviço de saúde, quando colonizados são freqüentemente associados a surtos. A prevenção do risco da colonização profissional está associada ao comportamento e dependente do conhecimento e crenças em saúde. Objetivo: analisar a prevalência de Staphylococcus aureus na saliva de trabalhadores da equipe de enfermagem, médicos, fisioterapeutas, terapeutas ocupacionais e auxiliares de limpeza de hospital universitário de grande porte. Metodologia: estudo epidemiológico longitudinal foi realizado com 486 trabalhadores no período de abril de 2006 a junho de 2008 e compreendeu a coleta de três amostras de saliva e aplicação de instrumento de coleta de dados, com perguntas abertas e fechadas. Staphylococcus aureus foram isolados do espécime clínico e caracterizados fenotipicamente; os resistentes à meticilina foram submetidos à detecção do gene mecA e identificação do cassete cromossômico SCCmec. Os dados quantitativos dos resultados laboratoriais e do instrumento foram organizados e processados no Programa EPI-Info e analisados por meio de estatística descritiva. Os dados relativos às perguntas abertas foram submetidos à análise quantitativa de discurso (BARDIN, 1977) e analisados de acordo com as categorias que emergiram a partir do conteúdo das respostas. Resultados: entre os trabalhadores investigados, 60,9% estavam colonizados por Staphylococcus aureus na saliva, sendo 67,9% carreadores transitórios e 32,1% carreadores persistentes; a prevalência de Staphylococcus aureus resistente à meticilina entre os isolados foi de 15,7%. A prevalência média de Staphylococcus aureus resistente à meticilina foi de 12,7% sendo maior entre técnicos em enfermagem (21,4%) e auxiliares de limpeza (20,6%) e menor entre enfermeiros (4,5%) e médicos (5,9%). O gene mecA foi detectado em 36,9% de Staphylococcus aureus resistentes à meticilina; SCCmec tipo IV foi identificado em dois isolados e tipo II em um isolado. As medidas preventivas da colonização mais valorizadas foram o uso de equipamentos de proteção individual e a adoção de medidas básicas de higiene e isolamento. Os trabalhadores percebem sua suscetibilidade à colonização e a referem como dependente de suas condições de saúde. As conseqüências da colonização e os benefícios na adoção de atitude preventiva foram associados ao paciente, família e ao próprio trabalhador; o conhecimento e as condições de trabalho foram referidos como os principais intervenientes na adoção das medidas de prevenção e controle. Conclusões: os trabalhadores apresentaram alta prevalência de Staphylococcus aureus na saliva, indicando a boca como importante sítio corporal para a investigação da colonização por Staphylococcus aureus resistente à meticilina e potencial fonte para sua disseminação. O perfil fenotípico revelou diferenças no perfil de sensibilidade aos antimicrobianos entre isolados resistentes e sensíveis à meticilina; assim como a multiresistência de Staphylococcus aureus resistentes à meticilina aos demais antimicrobianos testados. O estudo do conhecimento atrelado às crenças dos trabalhadores permitiu melhor compreensão do comportamento profissional e contribui para o planejamento de ações educativas, direcionadas à prevenção e controle de Staphylococcus aureus resistente à meticilina / The carrier state of methicillin-resistant Staphylococcus aureus is pointed as infection predictor among hospitalized patients, and factor for environmental and person to person dissemination, including health service workers, when colonized are commonly associate to outbreaks. Prevention of professional colonization risk is associated to behavior and dependent of knowledge and beliefs in health. Objective: analyze the prevalence of Staphylococcus aureus in saliva of workers of the nursing, medical, physiotherapist, occupational therapist and cleaning teams, at a big university hospital. Methodology: epidemiologic longitudinal study carried out with 486 workers between April 2006 and June 2008, three saliva samples were collected and a data collection instrument with open and closed questions was applied. Staphylococcus aureus were isolated from the clinical specimen and characterized by phenotypes; the methicillin-resistant were submitted to mecA gene detection and SCCmec chromosome cassette identification. Quantitative data from the instrument and the laboratory results were organized and processed with EPI-Info software and analyzed by descriptive statistics. Data from the open questions were submitted to quantitative discourse analysis (BARDIN, 1977) and analyzed according to the categories which emerged from the answer subjects. Results: among the researched workers, 60,9% were colonized by Staphylococcus aureus in saliva, of those 67,9% were transitory carriers and 32,1% persistent carriers; the prevalence of meticillin-resistant Staphylococcus aureus among the isolated was 15,7%. The average prevalence of methicillin-resistant Staphylococcus aureus was 12,7% and higher among nurses aides (21,4%) and cleaning aides (20,6%) and lower among nurses (4,5%) and doctors (5,9%). The mecA gene was detected in 36,9% of the methicillin-resistant Staphylococcus aureus; SCCmec type IV was identified in two isolates and type II in one isolate. The most valorized preventive measures were the use of individual protective devices and adoption of basic hygiene and isolation measures. Workers understand their susceptibility to colonization and see it as dependent of their health conditions. The consequences of colonization and the benefits of adopting preventive attitudes were associated to the patient, family and workers themselves; knowledge and working conditions were referred to as the main interventions in adopting control and prevention measures. Conclusions: workers presented high prevalence of Staphylococcus aureus in saliva, indicating mouth as an important body site to investigate colonization by methicillin-resistant Staphylococcus aureus and potential source to its dissemination. The phenotypic profile revealed differences on the antimicrobial sensibility profile between isolated resistant and meticillin-resistant; as well as the multi-resistance of the methicillin-resistant Staphylococcus aureus to the other antimicrobials tested. The study of workers knowledge and beliefs allowed a better comprehension of the professional behavior and contributed to the planning of educational actions, targeting methicillin-resistant Staphylococcus aureus prevention and control

Staphylococcus pseudintermedius affecting dogs is analogous to S. aureus on humans, acting as both normal flora and opportunistic pathogen. Methicillin resistance in S. pseudintermedius is recent, with the first documented occurrence of an isolate bearing the methicillin resistance gene, mecA, in 1999. This gene encodes penicillin binding protein 2a, which renders all beta-lactam drugs ineffective and functions as a “gateway” antibiotic resistance determinant. In the presence of ineffective antibiotics, opportunities for mutational events and acquisition of mobile genetic elements increase as microbial densities increase, often leading to multi-drug resistance. Methicillin-resistant S. pseudintermedius (MRSP) infections have become increasingly common. For example, approximately 30% of the S. pseudintermedius isolates tested by the University of Tennessee College of Veterinary Medicine Clinical Bacteriology Laboratory are resistant to methicillin. An increasing number of MRSP isolates are also resistant to most clinically useful antibiotics available to veterinarians except for chloramphenicol, and resistance to this antibiotic is common among European MRSP isolates. Chloramphenicol resistance has begun to appear in the US and if this trend continues there may soon be few viable antibiotic treatment options. Compared with the arrival of methicillin-resistant S. aureus in the 1960s, the opportunity currently exists to apply advanced molecular methods early in this recognized emergence of MRSP. To that end I have pursued projects utilizing multilocus sequence typing, pulsed-field electrophoresis, and SCCmec characterization of both susceptible and resistant S. pseudintermedius. The initial result was the detection of a clonal population of MRSP in the southeastern United States. Further characterization of this and other clonal lineages using genomic sequencing and real-time RT-PCR expression analysis of antibiotic resistance and quorum sensing genes revealed a marked difference in the regulation of antibiotic resistance between regional clones. These discoveries have interesting epidemiological implications and provide a foundation for the development of novel therapeutics to circumvent the expanding antibiotic resistance repertoire of MRSP. Potential targets identified by this work include membrane-bound beta-lactamase receptors responsible for the regulation of mecA, non-cognate auto-inducing peptides, and synthetic antisense oligonucleotides.

Thematic Paper (M.C.T.M. (Tropical Pediatrics))--Mahidol University, 2005.

Thematic Paper (M.C.T.M. (Tropical Pediatrics))--Mahidol University, 2005.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Staphylococcus aureus is considered as a microorganism belonging to the normal flora of humans, being both a settler as an infectious pathogen Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major cause of nosocomial infections and community. The large increase in resistance to antimicrobials has limited therapeutic options. Thus the proper conduct of testing the susceptibility to drugs is vital to ensure the proper treatment of these infections, and the use of methods capable of detecting resistance quickly and accurately, it is essential in clinical diagnosis . The aim of this study was to compare manual and automated phenotypic methods with genotypic based on Polymerase Chain Reaction (PCR) to detect MRSA strains. A total of 139 samples of S. aureus were analyzed using automated and manual methods phenotypic and compared with the determination of the mecA gene by PCR. A total of 139 samples, 37 (26.6 %) had the gene searched. The oxacillin had a sensitivity of 62.2% and specificity of 95.1 %, while cefoxitin disk for these parameters were 67.6% and 94.1 %, respectively. The automated method was the one that had the highest percentages of sensitivity (67,6 %) and specificity (96.1 %). Some differences were observed when comparing the phenotypic methods with PCR. A combination of methods can be considered as an efficient alternative for the diagnosis of infections caused by MRSA. / Staphylococcus aureus é considerado como um microrganismo pertencente à microbiota normal dos seres humanos, podendo ser tanto um colonizador como um patógeno infeccioso. Staphylococcus aureus resistente à meticilina (MRSA) emergiu como uma das principais causas de infecções nosocomiais e comunitárias. O elevado aumento na resistência a diferentes antimicrobianos tem limitado as opções terapêuticas. Assim, a realização adequada de testes de sensibilidade a essas drogas é vital para garantir o adequado tratamento dessas infecções, e o emprego de metodologias capazes de detectar esta resistência de forma rápida e precisa, torna-se imprescindível no diagnóstico clínico. O objetivo desse estudo foi comparar métodos fenotípicos manual e automatizado com o genotípico, baseado na Reação em Cadeia da Polimerase (PCR), para detectar cepas MRSA. Um total de 139 amostras de S. aureus foram analisadas por meio de métodos fenotípicos manuais e automatizado e comparadas com a determinação do gene mecA por PCR. De um total de 139 amostras, 37 (26,6%) apresentaram o gene pesquisado. O disco de oxacilina apresentou sensibilidade de 62,2% e especificidade de 95,1%, enquanto que para o disco de cefoxitina estes parâmetros foram 67,6% e 94,1%, respectivamente. O método automatizado foi o que obteve as maiores percentagens de sensibilidade (67,6%) e especificidade (96,1%). Algumas divergências foram observadas quando comparamos os métodos fenotípicos com a PCR. A combinação de metodologias pode ser considerada como uma alternativa eficiente no diagnóstico de infecções causadas por MRSA.

O estado de portador de Staphylococcus aureus resistente à meticilina é apontado como preditor de infecção principalmente entre pacientes hospitalizados, bem como fator para a disseminação ambiental e de pessoa a pessoa, incluindo trabalhadores de serviço de saúde, quando colonizados são freqüentemente associados a surtos. A prevenção do risco da colonização profissional está associada ao comportamento e dependente do conhecimento e crenças em saúde. Objetivo: analisar a prevalência de Staphylococcus aureus na saliva de trabalhadores da equipe de enfermagem, médicos, fisioterapeutas, terapeutas ocupacionais e auxiliares de limpeza de hospital universitário de grande porte. Metodologia: estudo epidemiológico longitudinal foi realizado com 486 trabalhadores no período de abril de 2006 a junho de 2008 e compreendeu a coleta de três amostras de saliva e aplicação de instrumento de coleta de dados, com perguntas abertas e fechadas. Staphylococcus aureus foram isolados do espécime clínico e caracterizados fenotipicamente; os resistentes à meticilina foram submetidos à detecção do gene mecA e identificação do cassete cromossômico SCCmec. Os dados quantitativos dos resultados laboratoriais e do instrumento foram organizados e processados no Programa EPI-Info e analisados por meio de estatística descritiva. Os dados relativos às perguntas abertas foram submetidos à análise quantitativa de discurso (BARDIN, 1977) e analisados de acordo com as categorias que emergiram a partir do conteúdo das respostas. Resultados: entre os trabalhadores investigados, 60,9% estavam colonizados por Staphylococcus aureus na saliva, sendo 67,9% carreadores transitórios e 32,1% carreadores persistentes; a prevalência de Staphylococcus aureus resistente à meticilina entre os isolados foi de 15,7%. A prevalência média de Staphylococcus aureus resistente à meticilina foi de 12,7% sendo maior entre técnicos em enfermagem (21,4%) e auxiliares de limpeza (20,6%) e menor entre enfermeiros (4,5%) e médicos (5,9%). O gene mecA foi detectado em 36,9% de Staphylococcus aureus resistentes à meticilina; SCCmec tipo IV foi identificado em dois isolados e tipo II em um isolado. As medidas preventivas da colonização mais valorizadas foram o uso de equipamentos de proteção individual e a adoção de medidas básicas de higiene e isolamento. Os trabalhadores percebem sua suscetibilidade à colonização e a referem como dependente de suas condições de saúde. As conseqüências da colonização e os benefícios na adoção de atitude preventiva foram associados ao paciente, família e ao próprio trabalhador; o conhecimento e as condições de trabalho foram referidos como os principais intervenientes na adoção das medidas de prevenção e controle. Conclusões: os trabalhadores apresentaram alta prevalência de Staphylococcus aureus na saliva, indicando a boca como importante sítio corporal para a investigação da colonização por Staphylococcus aureus resistente à meticilina e potencial fonte para sua disseminação. O perfil fenotípico revelou diferenças no perfil de sensibilidade aos antimicrobianos entre isolados resistentes e sensíveis à meticilina; assim como a multiresistência de Staphylococcus aureus resistentes à meticilina aos demais antimicrobianos testados. O estudo do conhecimento atrelado às crenças dos trabalhadores permitiu melhor compreensão do comportamento profissional e contribui para o planejamento de ações educativas, direcionadas à prevenção e controle de Staphylococcus aureus resistente à meticilina / The carrier state of methicillin-resistant Staphylococcus aureus is pointed as infection predictor among hospitalized patients, and factor for environmental and person to person dissemination, including health service workers, when colonized are commonly associate to outbreaks. Prevention of professional colonization risk is associated to behavior and dependent of knowledge and beliefs in health. Objective: analyze the prevalence of Staphylococcus aureus in saliva of workers of the nursing, medical, physiotherapist, occupational therapist and cleaning teams, at a big university hospital. Methodology: epidemiologic longitudinal study carried out with 486 workers between April 2006 and June 2008, three saliva samples were collected and a data collection instrument with open and closed questions was applied. Staphylococcus aureus were isolated from the clinical specimen and characterized by phenotypes; the methicillin-resistant were submitted to mecA gene detection and SCCmec chromosome cassette identification. Quantitative data from the instrument and the laboratory results were organized and processed with EPI-Info software and analyzed by descriptive statistics. Data from the open questions were submitted to quantitative discourse analysis (BARDIN, 1977) and analyzed according to the categories which emerged from the answer subjects. Results: among the researched workers, 60,9% were colonized by Staphylococcus aureus in saliva, of those 67,9% were transitory carriers and 32,1% persistent carriers; the prevalence of meticillin-resistant Staphylococcus aureus among the isolated was 15,7%. The average prevalence of methicillin-resistant Staphylococcus aureus was 12,7% and higher among nurses aides (21,4%) and cleaning aides (20,6%) and lower among nurses (4,5%) and doctors (5,9%). The mecA gene was detected in 36,9% of the methicillin-resistant Staphylococcus aureus; SCCmec type IV was identified in two isolates and type II in one isolate. The most valorized preventive measures were the use of individual protective devices and adoption of basic hygiene and isolation measures. Workers understand their susceptibility to colonization and see it as dependent of their health conditions. The consequences of colonization and the benefits of adopting preventive attitudes were associated to the patient, family and workers themselves; knowledge and working conditions were referred to as the main interventions in adopting control and prevention measures. Conclusions: workers presented high prevalence of Staphylococcus aureus in saliva, indicating mouth as an important body site to investigate colonization by methicillin-resistant Staphylococcus aureus and potential source to its dissemination. The phenotypic profile revealed differences on the antimicrobial sensibility profile between isolated resistant and meticillin-resistant; as well as the multi-resistance of the methicillin-resistant Staphylococcus aureus to the other antimicrobials tested. The study of workers knowledge and beliefs allowed a better comprehension of the professional behavior and contributed to the planning of educational actions, targeting methicillin-resistant Staphylococcus aureus prevention and control