Rapid Identification of Pathogens Recovered from Blood Stream Infections
Hassan Aziz, Linda L. Ross, Patricia Tille, Janice Conway-Klaassen
Int. J. Bio. Lab. Sci 2020 1:15-22
This study reviews the potential of newer rapid molecular-based methods to identify blood pathogens and/or to predict antibiotic resistance mechanisms that the organisms possess. Use of Peptide Nucleic Acid Fluorescence in Situ Hybridization (PNA-FISH) and matrix-assisted laser desorption ionization Time-of-Flight (MALDI-TOF) technologies are well-established methods for reducing turn-around-time in detecting the bacterial agent in positive blood cultures. Several manufacturers in the US, Europe and South Korea have developed methods and instrumentation to detect microorganisms directly from whole blood specimens without biological amplification on culture media. The assays utilize nucleic acid amplification of the organism DNA or RNA to a detectable level. Challenges with these methods are numerous as pathogens are present in low numbers in the circulating blood and the high background of human DNA can yield the assays less sensitive and specific. Many of the methods are not FDA-approved for use in the US although some have regulatory approval in Europe. Current rapid methods do not replace the traditional methods of culturing positive blood culture isolates to agar plates for definitive identification and antimicrobial susceptibility testing. Recent technological advances are making significant progress in the prompt detection and identification of pathogens and their antimicrobial resistance mechanisms in patients with sepsis. These new rapid methods show promise in the enhancement of patient care and positively influencing patient outcomes. Clinical and economic benefits of the rapid tests must be evaluated in conjunction with a robust antimicrobial stewardship program.
Key words: Blood Stream Infections, Pathogens, Blood cultures, Sepsis, molecular methods