Biologia molecular como ferramenta para o diagnóstico de fungemias: padronização de protocolos e comparação com métodos convencionais
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Data
2012-06-25
Autores
Siqueira, João Paulo Zen [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
As Infecções relacionadas à Assistência à Saúde (IRAS) estão entre as principais causas de morbidade e de mortalidade em ambiente hospitalar. Neste panorama, destacam-se as fungemias, que são estabelecidas quando há um comprometimento da resposta da resposta imune do hospedeiro. Os avanços médicos nas últimas duas décadas melhoraram a sobrevida dos pacientes críticos, o que levou a um aumento de infecções em UTI. O método diagnóstico atualmente utilizado para este tipo de infecção (hemocultura) é lento e apresenta baixa sensibilidade. Demais alternativas de diagnóstico rápido são essenciais por permitir a adoção da terapia antimicrobiana correta e diminuir o tempo de internação, evitando gastos e sobrecarga ao sistema de saúde. Deste modo, métodos moleculares são promissores por serem mais rápidos, precisos e sensíveis. Sendo assim, o objetivo geral deste estudo foi avaliar comparativamente técnicas laboratoriais diagnósticas para fungemia – método molecular (nested PCR) versus cultura – e associar aos aspectos clínicos dos pacientes, tempo de realização e custos. A população foi composta por 89 pacientes, sendo 67 provenientes de UTI Geral e 22 de UTI Neonatal, todos com suspeita de infecção sistêmica. Foram colhidas 118 amostras de sangue no total. Parte deste sangue era enviada ao Hospital, seguindo a rotina de hemocultura. Outra parte era destinada a realização da metodologia molecular. Após padronização, foi obtido como limiar de detecção da técnica, 10 células fúngicas por 4 ml de amostra. Em 46 (51,7%) foi detectada fungemia pelo nested PCR. Correlacionando com os fatores de risco, as doenças de caráter pulmonar, cardíaco e renal foram as doenças de base prevalentes; enquanto que o uso de cateter venoso central, ventilação mecânica e terapia antimicrobiana prévia foram...
Health-care associated infections (HAI) are among the leading causes of morbidity and mortality in a hospital environment. Medical advances over the past two decades have improved the survival of critically ill patients, which led to an increase of infections in ICU. In this scenario, stand out the fungemias, which are established when there is an impairment of host immune response. The diagnostic method currently used for this type of infection (blood cultures) is slow and has low sensitivity. A rapid diagnosis is essential to allow the adoption of the correct antimicrobial therapy and reduce hospitalization time, avoiding expenses and a burden the health-care system. Therefore, molecular methods for diagnosis are promising because they are faster, more accurate and more sensitive than conventional methods. Thus, the main objective of this study was to comparatively evaluate laboratory diagnostic techniques for fungemia – molecular method (nested PCR) versus culture – in association with clinical features of patients, performance time and its costs. The population consisted of 89 patients, 67 from General ICU and 22 from Neonatal ICU, all with suspicion of systemic infection. Were collected a total of 118 blood samples. A portion of this blood was sent to hospital, following the normal routine. Another part was destined to realization of the molecular method. After standardization, the detection threshold found was 10 fungal cells per 4 ml of sample. Considering the patients, in 46 (51.7%) fungemia was detected by nested PCR. Correlating with risk factors, pulmonary, cardiac and renal diseases were the most relevant underlying diseases; whereas, the use of central venous catheters, mechanical ventilation and prior antimicrobial therapy were the most important clinical features. In comparison, both methods... (Complete abstract click electronic access below)
Health-care associated infections (HAI) are among the leading causes of morbidity and mortality in a hospital environment. Medical advances over the past two decades have improved the survival of critically ill patients, which led to an increase of infections in ICU. In this scenario, stand out the fungemias, which are established when there is an impairment of host immune response. The diagnostic method currently used for this type of infection (blood cultures) is slow and has low sensitivity. A rapid diagnosis is essential to allow the adoption of the correct antimicrobial therapy and reduce hospitalization time, avoiding expenses and a burden the health-care system. Therefore, molecular methods for diagnosis are promising because they are faster, more accurate and more sensitive than conventional methods. Thus, the main objective of this study was to comparatively evaluate laboratory diagnostic techniques for fungemia – molecular method (nested PCR) versus culture – in association with clinical features of patients, performance time and its costs. The population consisted of 89 patients, 67 from General ICU and 22 from Neonatal ICU, all with suspicion of systemic infection. Were collected a total of 118 blood samples. A portion of this blood was sent to hospital, following the normal routine. Another part was destined to realization of the molecular method. After standardization, the detection threshold found was 10 fungal cells per 4 ml of sample. Considering the patients, in 46 (51.7%) fungemia was detected by nested PCR. Correlating with risk factors, pulmonary, cardiac and renal diseases were the most relevant underlying diseases; whereas, the use of central venous catheters, mechanical ventilation and prior antimicrobial therapy were the most important clinical features. In comparison, both methods... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Biologia molecular, Fungos patogenicos, Micologia medica, Microbiologia, Molecular biology
Como citar
SIQUEIRA, João Paulo Zen. Biologia molecular como ferramenta para o diagnóstico de fungemias: padronização de protocolos e comparação com métodos convencionais. 2012. 65 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências, Letras e Ciências Exatas, 2012.