Volume 21, Number 3—March 2015
Dispatch
Rapid Detection of ESBL-Producing Enterobacteriaceae in Blood Cultures
Laurent Dortet, Laurent Poirel, and Patrice Nordmann
Table 2
Results of MALDI-TOF and extended-spectrum β-lactamase NDP testing of 245 blood cultures positive for gram-negative bacilli and definitive identification and antibiotic resistance phenotype obtained with cultured bacteria*
| 30 min | 24–48 h | ||||
|---|---|---|---|---|---|
| MALDI-TOF identification |
No. |
ESBL NDP test |
Definitive identification |
β-Lactam resistance phenotype a |
|
| Enterobacteriaceae | |||||
| Escherichia coli | 38 | – | E. coli | Wild-type | |
| 47 | – | E. coli | Penicillinase | ||
| 1 | – | E. coli | IRT | ||
| 1 | – | E. coli | Low-level cephalosporinase | ||
| 1 | – | E. coli | Overexpressed cephalosporinase | ||
| 30 | + | E. coli | ESBL | ||
| Proteus mirabilis | 3 | – | P. mirabilis | Penicillinase | |
| Salmonella spp. | 1 | – | Salmonella Typhimurium | Wild-type | |
| 1 | – | Salmonella Enteritidis | Wild-type | ||
| 1 | – | Salmonella Paratyphi A | Wild-type | ||
| 1 | – | Salmonella Typhi | Wild-type | ||
| 1 | – | Salmonella Kentucky | Penicillinase | ||
| Klebsiella pneumoniae | 23 | – | K. pneumoniae | Wild-type | |
| 1 | – | K. pneumoniae | Acquired cephalosporinase | ||
| 13 | + | K. pneumoniae | ESBL | ||
| K. oxytoca | 5 | – | K. oxytoca | Wild-type | |
| Citrobacter koseri | 2 | – | C. koseri | Wild-type | |
| Enterobacter cloacae | 12 | – | E. cloacae | Wild-type | |
| 5 | – | E. cloacae | Overexpressed cephalosporinase | ||
| 3 | + | E. cloacae | ESBL | ||
| Enterobacter aerogenes | 5 | – | E. aerogenes | Wild-type | |
| Citrobacter braaki | 1 | – | C. braaki | Wild-type | |
| C. freundii | 1 | + | C. freundii | ESBL | |
| Morganella morganii | 4 | – | M. morganii | Wild-type | |
| Providencia rettgeri | 2 | – | P. rettgeri | Wild-type | |
| Proteus vulgaris | 1 | – | P. vulgaris | Wild-type | |
| Serratia marcescens | 4 | – | S. marcescens | Wild-type | |
| None | 1 | – | E. coli + Proteus mirabilis | Penicillinase + Penicillinase | |
| 2 |
– |
K. pneumoniae + S. marcescens |
Wild-type + Penicillinase |
||
| Nonfermenting bacilli | |||||
| Pseudomonas aeruginosa | 24 | – | Pseudomonas aeruginosa | Ceftazidime S | |
| Acinetobacter baumannii | 2 | – | A. baumannii | Ceftazidime S | |
| A. junii | 1 | – | A. junii | Ceftazidime S | |
| Stenotrophomonas maltophilia | 2 | – | Stenotrophomonas maltophilia | Ceftazidime S | |
| Roseomonas gilardii | 1 | – | Roseomonas gilardii | Ceftazidime S | |
| Sphingobacterium multivorum |
1 |
– |
Sphingobacterium multivorum |
Ceftazidime S |
|
| Anaerobic gram-negative bacilli | |||||
| Bacteroides fragilis | 1 | – | B. fragilis | Wild-type | |
| 1 | – | B. fragilis | Cefotaxime R | ||
| B. vulgatus |
1 |
– |
B. vulgatus |
Cefotaxime R |
|
| *MALDI-TOF, matrix-assisted laser desorption/ionization time-of-flight; NDP, Nordmann/Dortet/Poirel test; ESBL, extended spectrum β-lactamase; –, negative test result; IRT, inhibitor-resistant TEM β-lactamase; +, positive test result. | |||||
Page created: February 18, 2015
Page updated: February 18, 2015
Page reviewed: February 18, 2015
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