Background: Antibiotic resistance has rapidly grown into a worldwide problem that threatens to compromise the effective treatment of a plethora of diseases. A two-step test algorithm was developed for detection and identification of macrolide and ß-lactamantibiotics resistance genes.Methods & Materials: Bacterial isolates were first tested by a multiplex real-time PCR (mRT-PCR) covering eight genes in relation to macrolide (msrA, ermA, ermB, and ermC) and ß-lactam (blaTEM, blaSHV, blaCTX-M-1, blaCTX-M-9) resistances and the presence of one or multiple resistance genes were determinedbymelting temperature (Tm) profile analyses. Amplification products with indistinguishable Tm profiles were tested subsequently by a liquid beads microarray assay (LBMA) assay with the eight resistance gene-specific probes. The clinical validity was evaluated on 340 clinical isolates with phenotypic antimicrobial susceptibility results used as the standard comparison methods.Results: It has been shown that 75% of isolates can be identify by mRT-PCR and melting temperature analyses only, while the rest 25% need both two approaches. An overall agreement of 96.6% (kappa = 0.93, 95% CI = 0.89-0.96)was observed between the mRT-PCR-LBMA and phenotypic methods. The sensitivities and specificities were 94.5% and 97.5% for macrolide and 92.6% and 98.4% for ß-lactam resistance determination, respectively. Conclusion:The two-step mRT-PCR-LBMA assay provided a cost-effective toolfor rapid determination of macrolide and ßlactam antibiotic resistances.

Significance: Described here is a gold-catalyzed synthesis of 5,6-dihydro-8H-indolizin-7-ones from tethered enynyl b-lactams. The now well recognized selective C-C triple bond activation by the gold catalyst is followed by a 5-exo-dig cyclization and heterolytic fragmentation of the amide functionality to form a highly nucleophilic acyl cation. This species is proposed, without evidence, to undergo cyclization to the enamine to give the indolizinone core. Application of the synthetic methodology to the construction of the naturally occurring indolizidine 167B is described.Comment: The indolizidine and indolizine framework represent a fundamental and important class of heterocycles, which, in view of their use as antituberculosis agents, histamine H 3 receptor antagonists, and microtubule inhibitors, are attractive synthetic targets (). The starting enynyl b-lactams are readily constructed in a simple four step sequence. The substrate scope is moderately studied. However, most of the b-lactams and obtained indolizinone products were prone to decomposition over time. Gold-catalyzed reactions continue to be at the forefront of new synthetic method development (see Reviews below).