Rapid Detection of Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae from Urine Samples by Use of the ESBL NDP Test

Abstract

From June to September 2012, 500 urine samples were recovered from patients with urinary tract infections (UTI) due to Gramnegative bacilli (>10 4 leukocytes/ml and >10 5 Gram-negative isolates/ml) who visited the University hospital Bicêtre (France). They were challenged with extended-spectrum-␤-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) using the rapid diagnostic ESBL NDP test. Results of the ESBL NDP test were compared to the results of the double-disc susceptibility test (DDST) performed on solid-agar plates and molecular identification of the ␤-lactamase genes. Among the 450 nonduplicate urine samples, 11.3% were positive for ESBL-E by using the DDST, the ESBL determinants being mostly of the CTX-M type (CTX-M-15) according to molecular testing. Results of the ESBL NDP test were obtained within 15 min. The sensitivity and specificity of the ESBL NDP test were 98% and 99.8%, respectively, whereas the positive and negative predictive values of this test were 98% and 99.8%, respectively. A perfect correlation between cefotaxime resistance and positivity of the ESBL NDP test was observed. Therefore, the ESBL NDP test offers a powerful tool for a rapid identification of ESBL-E and associated resistance to expandedspectrum cephalosporins. It may be useful in particular for guiding first-line antibiotic therapy.

Comparison of Three Biochemical Tests for Rapid Detection of Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae

“…We believe that this is a major shortcoming in a comparison with the Rapid ESBL NDP test, since such a control allows a better appreciation of the color change (especially for weak-positive strains) and allows the detection of possible falsepositive results due to nonspecific reactions (11).…”

“…Also, it requires an additional delay (2 h versus 20 min) for reading the results that may be considered significant for patient management and antibiotic stewardship. Finally, we believe that the use of rapid biochemical tests for detecting ESBL producers from clinical sites (11,14) will be an alternative to molecular techniques, since they are easy to implement, affordable, and may detect any kind of ESBL.…”

Dissemination of High-Risk Clones of Extensively Drug-Resistant Pseudomonas aeruginosa in Colombia

“…Additionally, conventional PCR was used to screen for the presence of bla PER and bla GES (12). We performed phenotypic tests for carbapenemase production using the Carba NP test and a combined-disk method (CDM) using imipenem and cloxacillin in isolates that tested negative for the presence of carbapenemase genes (13,14). The sequencing of PCR products was performed in order to confirm the identities of the detected genes.…”

Development of a novel chromogenic method, Penta-well test, for rapid prediction of β-lactamase classes produced in clinical Enterobacteriaceae isolates

“…Although these methods are rapid and simple and allow direct assessment of clinical samples (Dortet et al, 2014a(Dortet et al, , 2014bGallah et al, 2014), their visual interpretation may give rise to ambiguity across different microbiology laboratories (Maurer et al, 2015;Simner et al, 2014;Tijet et al, 2013). Simner et al (2014) reported that the degree of color change used to determine positive results varied, while Tijet et al (2013) reported that intermediate color changes caused discrepancies between the interpretations of the findings made by 2 different laboratories.…”