Prevalência de DNA genômico para Staphylococcus epidermidis plasmo coagulase negativa em neonatos pré-termo maiores de três dias de vida e com quadro de piora de infecção

Abstract

Introduction: The neonatal infection (IN) is an important cause of morbidity and mortality in newborns in the neonatal period. One of the major infectious agents but no conclusive data is Staphylococcus epidermidis, the incidence of which is little known in IN. Object: This study aimed to identify the bacteria in the blood of newborns by polymerase chain reaction conventional (PCR) and real-time (qPCR), and check its incidence. Material and Methods: Was collected 45 peripheral blood samples for conventional blood culture (BacT / ALERT 3D60), and genomic DNA extraction from leukocytes. Approximately 50 ng (54 ±40 ng) of DNA was used for PCR in molecular diagnostics and qPCR. Oligonucleotide primers for PCR were designed and qPCR to obtain specific amplicons of 119 bp and 96 bp respectively for diagnosis of S. epidermidis. The qPCR was performed in the ABI Prism 7000 SDS equipment and reaction conditions according to the protocol of SybrGreen Core Reagent Mix. Result: Blood culture was able to detect S. epidermidis in 13,3% of the samples investigated, while conventional PCR detected 17,8% and qPCR 100% of target S. epidermidis DNA by the conventional PCR method. Conclusion: qPCR results showed increased sensitivity for the detection of S. epidermidis in the blood and will be a fundamental tool for future screening in broader epidemiological studies of suspected neonatal sepsis. Risk factors together with clinical observations and blood culture, coupled with PCR, will be more efficient for diagnostic accuracy and specific treatment direction.