Table 1 Current molecular techniques for detection of bloodstream infection, performed on positive blood cultures
From: Bench-to-bedside review: Rapid molecular diagnostics for bloodstream infection - a new frontier?
Assay/manufacturer | Technique | Anti-microbial resistance genes | Detectable pathogens | Detection limit (CFU/ml) | Turn- around time (h) | Costs equipment test and supplies | Sensitivity/specificity |
|---|---|---|---|---|---|---|---|
PNA-FISH (AdvanDX, MA, USA) | Fluorescence-based hybridization with PNA probes | None | S. aureus, CoNS, Enterococcus faecalis, Enterococcus faecium, Streptococcus pneumoniae, E. coli, Pseudomonas aeruginosa, Candida albicans, C. parapsilosis, C. glabrata, C. krusei, C. tropicalis | NA | 1.5-3 | $/++ | >98%/>98% |
Chemi-luminescent DNA probes detect rRNA | None | Streptococcus pneumoniae, enterococci, streptococci group A and B | NA | 2.5 | $$$/+++ | 72%/>99% | |
Nanosphere Verigene BC-GP | Multiplex PCR | mecA, vanA, vanB | S. aureus, S. epidermidis, S. lugdunensis, S. anginosus group, S.agalactiae, S. pyogenes, Enterococcus faecalis, E. faecium, Listeria spp., Micrococcus spp. | NA | 2.5 | $$/++ | >98%/>98% |
MALDI-TOF (bioMérieux, France or Bruker Daltonics, Germany) | Mass spectral signal recognition, laser desorption ionisation, mass spectrometry | None | Same pathogens as usually detected by blood cultures. Limitations in presence of polymicrobial bacteraemia or with some closely related organisms (for example, viridians Streptococcus spp., Streptococcus pneumonia identified as Streptococcus parasanguinis, Shighella sonnei identified as E. coli) | NA | <1-2 | $$$/+ | >76%/>96% (genus level) |
Plex-ID (Abbott , USA) | Multiplex PCR detected by electrospray ionization mass spectrometry | mecA, van | Same pathogens as usually detected by blood cultures. High positive agreement with MALDI-TOF | NA | <3 | $$$$/++ | NA/NA |
Hyplex Bloodscreen(BAG, Germany) | Multiplex PCR, hybridization on ELISA plate | mecA, van | MSSA, MRSA, S. epidermidis, S. pyogenes, S. pneumoniae, E. faecium, E. faecalis, E. coli, E. aerogenes, P. aeruginosa, Klebsiella spp. | NA | 3 | $/++ | >96%/>92% |
Prove-it Sepsis (Mobidiag, Finland) | Multiplex PCR + hybridization on microarray | mecA | CoNS, S. aureus, S. epidermidis, S. pyogenes, S. agalactiae, S.dygalactiae ss. Equisimilis, S. pneumoniae, E. faecalis, E. faecium, Listeria monocytogenes, Clostridium perfringens, Propionibacterium acnes, Enterobacteriaceae, E. coli, K. oxytoca, K. pneumoniae, E. aerogenes, E. cloacae, P. mirabilis, P. vulgaris, Salmonella spp., Serratia marcescens, Campylobacter spp., H. in uenzae, Neisseria spp., Kingella kingae, Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Bacteroides fragilis, | NA | 3 | $/++ | >94%/98% |
Black-Light (BlackBio, Spain) | Broad-range PCR and pyrosequencing | NA | Multiple sepsis pathogens, including Candida spp., Aspergillus fumigatus, Aspergillus niger | NA | 4 | $$$/++ | NA/NA |
StaphPlex system(Qiagen, CA, USA) | Multiplex PCR + lbead-based suspension array | Tuf, nuc, meqA, aacA, ermA, ermC, tetM, tetK | 18 Staphylococcus genes (S. aureus and most clinically relevant coagulase negative staphylococci) | NA | 5 | $$$/++ | 72-100%/>95% |
Staph SR (BD GeneOhm, CA, USA) | Real-time multiplex PCR | mecA | S. aureus (MRSA/MSSA detection) | NA | 2.5-3 | $$/++ | >95%/>85% |
Gene Xpert MRSA/MSSA(Cepheid, CA, USA) | Real-time multiplex PCR | SCCmec, mecA | S. aureus (MRSA/MSSA detection) | NA | 1 | $$$/+++ | >98%/>98% |
KeyPath (Microphage, USA) | Real-time pathogen- specific PCR | mecA, nuc | S. aureus (MRSA/MSSA detection) | NA | <5 | $$/++ | 100%/100% |