[Presumptive tests and molecular hybridization for the identification of untypable strains of Streptococcus...

Five different methods for identification of pneumococci (optochine susceptibility, bile solubility, Slidex Pneumo-kit, Phadebact Pneumococcus test, AccuProbe DNA test) were evaluated with a total of 280 Streptococcus pneumoniae non typable strains. 189 strains were identified as pneumococci according to the AccuProbe test results. Among these, 180 strains (95.2%) were optochine sensitive (d > or = 12 mm). Bile solubility was seen in 125 (66.1%) of the pneumococci. Immunological identifications were respectively positive for 67 and 56 among 140 strains. By comparison with the DNA/RNA reassociation method, the poor sensitivities and specificities of the presumptive identification tests are actually demonstrated for pneumococcal non typable strains. Thus, the AccuProbe DNA test is seen as the only adequate method for identification of such strains.