Table 1.
Clinical isolates used during the validation processa
| Organism | Total no. of strains | No. of known KPC+ strains | No. of known other β-lactamase+ strains | No. of unknown KPC+ strains | No. of unknown KPC− strains | No. of WT strainsb |
|---|---|---|---|---|---|---|
| Klebsiella sp. | 78 | 48 | 15 | 9 | 2 | 3 |
| Escherichia coli | 34 | 2 | 25 | 1 | 5 | 1 |
| Enterobacter sp. | 27 | 9 | 8 | 2 | 6 | 2 |
| Serratia marcescens | 4 | 0 | 3 | 0 | 0 | 1 |
| Citrobacter freundii | 3 | 1 | 0 | 1 | 0 | 1 |
| Salmonella sp. | 4 | 0 | 3 | 0 | 0 | 1 |
| Shigella sp. | 2 | 0 | 0 | 0 | 0 | 2 |
| Pseudomonas aeruginosa | 11 | 5 | 4 | 0 | 1 | 1 |
| Acinetobacter baumannii | 2 | 0 | 0 | 0 | 0 | 2 |
| Proteus mirabilis | 1 | 0 | 1 | 0 | 0 | 0 |
| Total | 166 | 66 | 59 | 13 | 14 | 14 |
a
Known strains were previously characterized for possessing specific β-lactamases and were used for initial assay validation. Unknown isolates were tested after initial assay validation between May 2011 and February 2012.
b
Non-β-lactamase-producing strains or strains producing chromosomal β-lactamases but susceptible to oxyimino-cephalosporins and carbapenems.