Testes moleculares in-house para detecção de bactérias e genes de resistência aos antimicrobianos direto de frascos de hemoculturas

• Autor(a) principal: Quiles, Milene Goncalves [UNIFESP]
• Data de Publicação: 2017
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UNIFESP
• Texto Completo: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=4996411; http://repositorio.unifesp.br/handle/11600/50734
• topic: Bloodstream infection; Molecular diagnosis; Stewardship; Molecular panels; Polymerization chain reaction; Bacteremia; Infecções de corrente sanguínea; Hemocultura; Diagnóstico molecular; Maldi-TOF MS; Reação em cadeia da polimerase; Resistência bacteriana

ABSTRACT Bloodstream infections (BSI) are important causes of morbidity and mortality. Recent studies described rates higher than 500,000 BSI episodes per year with more than 79,000 deaths annually. Molecular methods become increasingly frequent in clinical laboratories. The implantation of these methods in laboratory routine allows great sensitivity and speed in the results, collaborating for the therapeutic conduct of these infections. In order to validate the combined use of MALDI-TOF MS and in-house real-time PCR techniques for the rapid diagnosis of BSIs, we developed three studies: Study 1: This is a overview of commercial molecular tests and platforms available for the diagnosis of BSI, as well the clinical impact described when using these new technologies. Study 2: The purpose of this study was to validate a molecular protocol to identify bacteria and resistance genes in 166 positive blood cultures from 139 patients admitted to three different hospitals and to compare the results with those obtained from routine phenotypic methods. There was overall agreement for genius identification in 95.4% and at species level in 81.8% of the samples. In Enterobacteriaceae, the detection of carbapenem-resistance was concordant in 95.5% and cephalosporins (ESBL profile) in 87.5%. Among non-fermentative rods, there was agreement in 80% in the detection of carbapenem-resistance. For Gram positive, the methods agreed on 100% for the detection of vancomycin-resistance in enterococci and 77.1% for methicillin-resistance in staphylococci. Study 3: This study aimed to determine the intra-laboratory time required to identify pathogens and resistance genes in 113 episodes of ICS which molecular results were conclusive, as well as the evaluation of the antimicrobial adequacy in these episodes after the immediate communication of the results to phisycians from three participating centers. The mean untecipation time for results was 35 hours from traditional blood culture. Antimicrobial therapeutic modification occurred in 25 episodes, in which 16 were escalate and 10 de-escalate agents. In these cases, the antibiotics were adequate in 22 and inadequate in 3 which molecular results were discordants of the phenotypic. The major modifications occurred in Gram negative microorganisms, with the prescription of carbapenems in six episodes and polymyxin B in three. Conclusion: The molecular protocol proved to be in good agreement with conventional routine tests. In addition, the protocol provided a rapid result, considerably anticipating the time to antimicrobial therapeutic adequacy of the BSIs episodes.