O uso indiscriminado de antimicrobianos na suinocultura nacional e mundial tem sido uma prática comum, visando minimizar possíveis falhas no manejo e no ambiente em que vivem os animais, no entanto, este uso é descrito como potencial fator de risco na seleção de estirpes resistentes à antimicrobianos, entre elas as estirpes de Staphylococcus aureus resistentes à meticilina (MRSA). O presente estudo revelou o uso médio de 358,0 mg diferentes antimicrobianos/ kg de suíno produzido nos 25 sistemas de produção pesquisados, sendo este valor considerado elevado, quando comparado a tendência global de 172,0 mg, bem como período médio de exposição de 66,3% da vida dos animais e exposição à 7 diferentes princípios ativos em média, variando de 2 a 11. A pesquisa de animais carreadores de estirpes MRSA revelou 80,0% dos sistemas de produção positivos, sendo 68,0% positivos para LA-MRSA-ST398, e 60,0% positivos para a presença do gene czrC, codificador de resistência ao óxido de zinco e cádmio. Não foi evidenciada correlação significativa entre o uso de antimicrobianos, nível de biossegurança, produtividade, status dos rebanhos para Mycoplasma hyopneumoniae, tipo de criação em sítio único (ciclo completo) ou dois sítios e positividade para MRSA. Apesar da ausência das correlações significativas ficou evidente no presente estudo a possibilidade de grandes melhorias nos programas de biossegurança, manejo, assim como nos programas de utilização de antimicrobianos. A alta frequência de sistemas de produção positivos para as estirpes MRSA são um importante alerta para o risco de disseminação deste agente para os seres humanos. / The indiscriminate use of antimicrobials in Brazilian and global pig farms has been a common practice in order to minimize possible failures in the management and environment in which animals live, however, this use is described as a potential risk factor in the selection of strains resistant to antimicrobials, including strains of methicillin resistant Staphylococcus aureus (MRSA). The present study revealed the average use of 358.0 mg of different antimicrobials / kg of pig produced in the 25 production systems surveyed, which is considered high when compared to the overall trend of 172.0 mg, as well as the mean exposure period of 66.3% of the animals life and exposure to 7 different active principles on average ranging from 2 to 11. Research on MRSA strains showed 80.0% of the positive production systems, and 68.0% were positive for MRSA strains. LA-MRSA-ST398, and 60.0% positive for the presence of the czrC gene, encoding resistance to zinc oxide and cadmium. There was no significant correlation between antimicrobial use, biosafety level, productivity, herd status for Mycoplasma hyopneumoniae, single site (complete cycle) or two sites and MRSA positivity. Despite the absence of significant correlations, it was evident in the present study the possibility of great improvements in biosafety programs, management, as well as in programs for the use of antimicrobials. The high frequency of positive production systems for MRSA strains is an important warning for the risk of dissemination of this agent to humans.

Orientador: Alexandre Secorun Borges / Resumo: Staphylococcus spp. causam várias enfermidades em humanos e animais. O crescente desenvolvimento de resistência bacteriana aos antimicrobianos convencionais dificulta o tratamento das infecções por esses micro-organismos, e é considerado problema de saúde humana e animal. Foi investigada a frequência e distribuição de clones de Staphylococcus spp. resistentes a meticilina (MRS) em equinos hospitalizados e profissionais da área (médicos veterinários e funcionários), bem como avaliar possível transmissão interespécies. Foram colhidas 131 amostras de suabe nasal de equinos e 35 de humanos, cultivados em ágar de ovo-telurite-glicina-piruvato (BD Baird-Parker Agar®). Os micro-organismos foram submetidos à coloração de Gram, identificação por provas bioquímicas e métodos genotípicos (PCR) e ITS-PCR para caracterização das espécies. A sensibilidade aos antimicrobianos foi determinada pelo método de concentração inibitória mínima (MIC). O perfil clonal e identificação da estirpe dos Staphylococcus spp. foi caracterizado por Eletroforese em Gel de Campo Pulsado (PFGE) e pelo Multilocus sequence Typing (MLST). O gênero Staphylococcus foi isolado em 17,5% (23/131) dos equinos, dos quais, 8,4% (11/131) foram identificados como S. hyicus, 3,8% (5/131) S. aureus, 3,8% (5/131) S. pseudintermedius e 1,5% (2/131) S. schleiferi. Foi detectado o gene mecA em um isolado de S. pseudintermedius. Nos 35 humanos amostrados, foram identificados 40% (14/35) de S. aureus. A tipagem molecular por PFGE p... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Background: MRSA or Methicillin-resistant Staphylococcus aureus consists of several strains in the bacterial species called Staphylococcus aureus. MRSA is resistant to methicillin but also to other types of antibiotics. Spread can occur both directly between humans and between humans and animals, but also indirectly through air. The number of positive bacterial cultures for MRSA in Sweden increases every year. The prevalence of MRSA of different types varies in different countries. LA-MRSA is a livestock-associated methicillin-resistant Staphylococcus aureus that was first discovered in the Netherlands in pigs. This bacterial type belongs to a specific clone called CC398 (clonal complex 398), were most belonged to a specific sequence type called ST398 (multi locus sequence type 398). The CC398 strain are constantly acquiring new features including virulence factors such as the PVL-gene has been reported and associated with serious infections in humans and animals. This specific bacterial clone is found primarily in food producing animals around Europe, and it can infect humans and cause infection. It occurs mainly in pigs and can be spread through contaminated pork or other meat products to humans. Purpose: This work was aimed to survey the prevalence of LA-MRSA in the countries from which Sweden imports most meat from and to review the spread from meat products. Method: This study is been based on information on antibiotic use among food producing animals and the proportion of reported cases of MRSA in the countries from which meat was imported. Scientific studies in all countries was used to obtain information on the prevalence of MRSA CC/ST 398 and on its characteristics. Results: The countries from which Sweden imports most meat are Germany, Denmark and the Netherlands, pork import dominates. In 2018 there were 27,260 tonnes of pork imported from Denmark and 45,197 tonnes from Germany, compared with imports from the Netherlands, which amounted to 6,888 tonnes. Germany has the highest antibiotic consumption and the highest proportion of reported cases of MRSA among these countries. In Denmark, the CC/ST 398-clone caused 17 blood infections and 700 skin and soft tissue infections between 2010 and 2015. In Germany, 166 of 330 pigs examined in 2012 were positive for the same clone, as was 77 of the 134 collected samples from the environment and 39 of the 63 animal caretakers. In Brazil, CC / ST398 was found in 6 of 1852 children, genotypic characterization indicated it was an MSSA (methicillin-sensitive S. aureus) CC398 that had acquired SCCmec genes in the health care system. In Italy 81 of 215 pig isolates collected were positive for MRSA where the dominant type was CC / ST398. Virulence genes associated with human MRSA strains such as enterotoxin and PVL genes were not present among the pig isolates. Resistance to tetracycline was seen in all pig isolates. In the Netherlands, MRSA CC / ST398 was linked to pigs in that sense that the humans that were infected were exposed to pigs on a daily basis. Conclusion: The prevalence of LA-MRSA CC / ST398 was high in all the countries surveyed. Resistance to tetracyclines was significantly higher among pig isolates compared to HA-MRSA isolates (healthcare-associated MRSA), whereas the virulence genes such as the PVL- gene usually not present detected in pig- isolates. Among strains identified as LA-MRSA CC / ST398 acquired SCCmec-genes were of types V and IV.  The spread from pigs or meat was through direct contact but also through air.