A collaborative evaluation of a rapid, semi-automated identification system for gram-negative bacilli: the Quantum II...

The recently-introduced semi-automated bacterial identification system, the Quantum II BID, is designed to identify fermentative and non-fermentative gram-negative bacilli in 4-5 h. The system was evaluated independently by the two participating laboratories. Inter-laboratory reproducibility was determined by testing 181 strains in each laboratory and found to be 97.8%. A further 893 organisms, comprising 417 fresh clinical isolates and 476 stock cultures, were then tested by the system in the two laboratories. Of the fresh clinical isolates, 95.7% yielded the same result as the comparative system used (API 20E) and 93.1% of the stock strains were assigned to their expected, previously established identity. Overall agreement between the two systems for all strains examined was 94.3%. There was no significant statistical difference between the results obtained in the two laboratories.