Rapid identification of bacteria, mecA and van genes from blood cultures

Abstract The Genotype technology, a quick molecular genetic assay based on DNA multiplex amplification with biotinylated primers followed by hybridization to membrane bound probes, complies with the requirements for a fast diagnosis of sepsis. We evaluated the new Genotype ® BC Gram-negative and Gram-positive test kits (Hain Life Science, Germany) which respectively allow for the identification of 15 species of Gram-negative (GN) rods, and the identification of 17 Gram-positive (GP) bacteria species together with the determination of methicillin and vancomycin resistance ( mec A and van genes). The study was performed on 60 positive blood cultures from BacT/ALERT bottles (aerobic, anaerobic and pediatric bottles). First, a Gram stain was carried out to select between Genotype ® BC GP or GN test, then identification were performed by the Genotype ® BC tests and by biochemical conventional tests after subculture and phenotypic susceptibility determination. The operating procedure was very easy to carry out and required a small amount of starting material (5 to 10 μL of blood culture). The results were available within 4.5 hours. For all the blood cultures, the Genotype ® BC results correlated with the biochemical identification and phenotypic antibiotics susceptibility. According to our results, this DNA strip technology based assay can easily be incorporated into routine diagnosis.