TABLE 1.
Isolates tested and test results
| Group and β-lactamase (no. of isolates) | Bacterial species included (no. of isolates) | No. of isolates with a positive test/no. of isolates tested (%)a |
|
|---|---|---|---|
| CNPt-CLSI | CNPt-direct | ||
| Class A carbapenemase producers | |||
| KPC-2 (27) | Klebsiella pneumoniae (11), Enterobacter cloacae (5), Serratia marcescens (3), Citrobacter freundii (2), Escherichia coli (2), Citrobacter braakii (1), Enterobacter aerogenes (1), Pseudomonas aeruginosa (1), Salmonella spp. (1) | 25/27 (93) | 27/27 (100) |
| KPC-3 (7) | K. pneumoniae (3), E. cloacae (2), C. freundii (1), E. coli (1) | 7/7 (100) | 7/7 (100) |
| IMI-1/NMC-A (4) | E. cloacae (3). Enterobacter asburiae (1) | 4/4 (100) | 4/4 (100) |
| Sme-1b (4) | S. marcescens (4) | 3/4 (75) | 4/4 (100) |
| GES-3 (2) | Enterobacter agglomerans (1), K. pneumoniae (1) | 1/2 (50) | 2/2 (100) |
| GES-5 (1) | P. aeruginosa (1) | 0/1 (0) | 1/1 (100) |
| All (45) | 40/45 (89) | 45/45 (100) | |
| Class B carbapenemase producers | |||
| NDM-1 (17) | Providencia rettgeri (4), Providencia stuartii (3), E. coli (3), K. pneumoniae (2), Acinetobacter baumannii (1), Acinetobacter pittii (1), E. cloacae (1), Morganella morganii (1), Proteus mirabilis (1) | 12/17 (71) | 17/17 (100) |
| IMP-1 (3) | Acinetobacter ursingii (1), Acinetobacter junii (1), Acinetobacter johnsonii (1) | 3/3 (100) | 3/3 (100) |
| IMP-7 (1) | P. aeruginosa (1) | 1/1 (100) | 1/1 (100) |
| IMP-8 (2) | E. cloacae (1), C. braakii (1) | 2/2 (100) | 2/2 (100) |
| IMP-13 (2) | P. aeruginosa (2) | 2/2 (100) | 2/2 (100) |
| IMP-16 (2) | P. aeruginosa (2) | 2/2 (100) | 2/2 (100) |
| IMP-18 (1) | P. aeruginosa (1) | 1/1 (100) | 1/1 (100) |
| IMP-27 (1) | P. mirabilis (1) | 0/1 (0) | 0/1 (0) |
| VIM-1 (3) | E. coli (2), E. cloacae (1) | 3/3 (100) | 3/3 (100) |
| VIM-2 (5) | P. aeruginosa (3), E. cloacae (1), P. rettgeri (1) | 4/5 (80) | 5/5 (100) |
| VIM-11 (1) | E. cloacae (1) | 0/1 (0) | 1/1 (100) |
| SPM-1 (2) | P. aeruginosa (2) | 2/2 (100) | 2/2 (100) |
| All (40) | 32/40 (80) | 39/40 (98) | |
| Class D carbapenemase producers | |||
| Enterobacteriaceae | |||
| OXA-48 (16) | K. pneumoniae (8), E. coli (7), Klebsiella oxytoca (1) | 15/16 (94) | 16/16 (100) |
| OXA-181 (10) | K. pneumoniae (6), E. coli (4) | 8/10 (80) | 10/10 (100) |
| OXA-232 (5) | K. pneumoniae (5) | 3/5 (60) | 4/5 (80) |
| OXA-244 (1) | E. coli (1) | 0/1 (0) | 0/1 (0) |
| OXA-247 (2) | E. coli (1), b K. pneumoniae (1) | 2/2 (100) | 2/2 (100) |
| OXA-438 (2) | E. coli (2) | 2/2 (100) | 2/2 (100) |
| All Enterobacteriaceae (36) | 30/36 (83) | 34/36 (94) | |
| Acinetobacter spp. | |||
| OXA-23 (20) | A. baumannii (20) | NAc | 19/20 (95) |
| OXA-58 (16) | A. baumannii (12), A. lwoffii (2), A. junii (1), A. guillouiae (1) | NA | 15/16 (94) |
| OXA-72 (1) | A. baumannii (1) | 1/1 (100) | |
| OXA-143 (1) | A. baumannii (1) | NA | 1/1 (100) |
| OXA-23 + OXA-58 (2) | A. baumannii (2) | NA | 2/2 (100) |
| All Acinetobacter (40) | NA | 38/40 (95) | |
| Carbapenemases nonproducers | |||
| ESBLs (35)d | K. pneumoniae (24), E. coli (4), P. aeruginosa (3), E. aerogenes (1), K. oxytoca (1), S. marcescens (1), S. flexneri (1) | 0/35 (0) | 0/35 (0) |
| AmpCs (15)e | E. cloacae (10), C. freundii (2), E. coli (2), E. aerogenes (1) | 0/15 (0) | 0/15 (0) |
| AmpCs + ESBLs (6)f | E. cloacae (6) | 0/6 (0) | 0/6 (0) |
| Narrow spectrum (9)g | A. baumannii (5), E. coli (2), P. aeruginosa (1), P. mirabilis (1) | 0/9 (0) | 0/9 (0) |
| None (nonenzymatic carbapenem-resistant isolates and QC strains) (40)h | P. aeruginosa (38), E. coli (2) | 0/40 (0) | 0/40 (0) |
| All nonproducers (105) | 0/105 (0) | 0/105 (0) | |
False-negative results are shown in italics.
E. coli J53 transconjugant strain.
NA, not applicable (an alternative procedure is required for optimal detection of OXA-type carbapenemases among Acinetobacter spp., as described in reference 8.
CTXM-2, n = 15; CTXM-15, n = 9; CTXM-13, n = 1; CTXM-14, n = 1; GES-1, n = 3; PER-2, n = 1; SHV-1, n = 1; SHV-5, n = 2; SHV-18, n = 1; SHV-27, n = 1.
Hyperproduction of chromosomally mediated cephalosporinase, n = 15; CMY-2, n = 2; DHA-1, n = 1.
Hyperproduction of chromosomally mediated cephalosporinase plus CTXM-2, n= 2; TEM-3, n = 1; TEM-5, n = 1; TEM-26, n = 1; SHV-3, n = 1.
OXA-51 (without upstream ISAba1), n = 5; TEM-1, n = 1; TEM-2, n = 1; OXA-1, n = 2.
Nonenzymatically carbapenem-resistant isolates and quality control (QC) strains, i.e., Pseudomonas aeruginosa carbapenem resistant because of efflux overproduction (n = 5), porin loss (n = 5), or dual mechanisms (n = 18), and quality control strains P. aeruginosa ATCC 27853 and Escherichia coli ATCC 25922.