Table 1. β-Lactamase types and modified Hodge test results of 136 carbapenem-resistant Enterobacteriaceae isolates according to species.
| Species | Total N | β-Lactamase types by PCR (N of isolates/N of MHT-positive isolates in at least one of variable combinations) | ||
|---|---|---|---|---|
| MBL carbapenemases (N=33) | AmpC-CH (N=58) | Other CRE (N=45) | ||
| Klebsiella pneumoniae | 74 | NDM-1 (14/11) | CIT (1/0), DHA-1 (13/0), CTX-M-15 (3/0), DHA-1/CTX-M-15 (3/0), DHA-1/CTX-M-14 (2/1), Unspecified* (3/0) | DHA-1 (8/0), CTX-M-15 (9/4), CTX-M-14 (1/0), DHA-1/CTX-M-15 (1/0), Unspecified* (16/6) |
| Enterobacter cloacae | 29 | NDM-1 (3/3), VIM-2 (3/3), Unidentified (1/1) | ACT-1 (11/3), DHA-1(1/0), CTX-M-15 (3/3), Unspecified* (6/2) | ACT-1 (1/0) |
| Enterobacter aerogenes | 11 | - | Unspecified* (9/8) | CTX-M-14 (1/0), Unspecified* (1/1) |
| Escherichia coli | 6 | - | CIT (2/0), unspecified* (1/0) | CTX-M-15 (1/1), Unspecified* (2/0) |
| Citrobacter freundii | 7 | NDM-1 (4/3), VIM-2 (3/3) | - | - |
| Serratia marcescens | 6 | NDM-1 (3/3), VIM-2 (1/1) | - | DHA-1 (1/1), CTX-M-15 (1/0) |
| Klebsiella oxytoca | 1 | NDM-1 (1/1) | - | - |
| Morganella morganii | 1 | - | - | DHA-1 (1/1) |
| Providencia stuartii | 1 | - | - | DHA-1 (1/0) |
*The term 'unspecified' means that the isolate was negative for all PCR tests performed.
Abbreviations: MBL, metallo-β-lactamase; AmpC-CH, AmpC β-lactamase with carbapenem-hydrolyzing activity; Other CRE; other β-lactamases than MBL or AmpC-CH; NDM, New Delhi metallo-β-lactamase; CIT, Citrobacter freundii-type; VIM, Verona imipenemase. CRE, carbapenem-resistant Enterobacteriaceae.