False Immunological Detection of CTX-M Enzymes in Klebsiella oxytoca

Rosa, José Manuel Ortiz de la; Demord, Anthony; Poirel, Laurent; Greub, Gilbert; Blanc, Dominique; Nordmann, Patrice

doi:10.1128/jcm.00609-21

Cited by 8 publications

(9 citation statements)

References 12 publications

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“…It is intriguing that no correlation was found between cross-reactivity and pairwise identity with CTX-M-2, which is their closest CTX-M member in phylogenetic analysis. In the case of OXY β-lactamases, it was previously hypothesized that residues of the Lys-Lys-Ser (KKS) triplet at Amber positions 101 to 103 was responsible for the cross-reactivity and explains why false-positive results occurred with the OXY-1 group but not the OXY-2 group variants [ 25 ]. Our results showed that several β-lactamases with amino acid triplets other than KKS at those positions also yielded false-positive results, including an OXY-2 variant and several other β-lactamases (FONA-8, -9, -11, -13 and SFO-1).…”

Section: Discussionmentioning

confidence: 99%

“…This indicates that cross reactivity is complex and might be influenced by protein folding and the level of β-lactamase expression. OXY and FONA are chromosomally-encoded ESBLs in K. oxytoca and S. fonticola , respectively, whereas SFO-1 is an uncommon plasmid-mediated ESBL that has been detected in members of Enterobacterales [ 25 , 26 , 27 ]. Since these are ESBL-producers anyway, the cross-reactions with CTX-M are of little clinical relevance.…”

Section: Discussionmentioning

confidence: 99%

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Evaluation of a Lateral Flow Immunoassay for Rapid Detection of CTX-M Producers from Blood Cultures

et al. 2023

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Bacteremia caused by extended-spectrum β-lactamases-producing Enterobacterales has increased rapidly and is mainly attributed to CTX-M enzymes. This study aimed to evaluate the NG-Test® CTX-M MULTI lateral flow assay (CTX-M LFA) for rapid detection of CTX-M producers in blood cultures (BCs) positive for Gram-negative bacilli in spiked and clinical BCs. Retrospective testing was performed on BC bottles spiked with a collection of well-characterized Enterobacterales isolates producing CTX-M (n = 15) and CTX-M-like (n = 27) β-lactamases. Prospective testing of clinical, non-duplicate BCs (n = 350) was performed in two hospital microbiology laboratories from April 2021 to March 2022 following detection of Gram-negative bacilli by microscopic examination. Results were compared against molecular testing as the reference. In the spiked BCs, the CTX-M LFA correctly detected all CTX-M producers including 5 isolates with hybrid CTX-M variants. However, false-positive results were observed for several CTX-M-like β-lactamases, including OXY-1-3, OXY-2-8, OXY-5-3, FONA-8, -9, -10, 11, 13 and SFO-1. In clinical BCs, the CTX-M LFA showed 100% (95% CI, 96.0–100%) sensitivity and 99.6% (97.9–100%) specificity. In conclusion, this study showed that rapid detection of CTX-M producers in BC broths can be reliably achieved using the CTX-M LFA, thus providing an opportunity for early optimization of antibiotics.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Evaluation of a Lateral Flow Immunoassay for Rapid Detection of CTX-M Producers from Blood Cultures

et al. 2023

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“…For CPE strains not suspected to produce an ESBL, the modified CDD test may be performed (only with class B CPE) for confirmation of suspected AmpC production. Furthermore, K. oxytoca CPE isolates suspected to produce an ESBL and/or AmpC may be subjected to the modified CDD test, since for these strains the CTX-M-MULTI test is unreliable due to production of an intrinsic OXY-1 β-lactamase, which may give rise to false-positive results ( 15 ). Strains of species producing an intrinsic AmpC may also be initially examined using the CTX-M-MULTI test when ESBL production is suspected.…”

Section: Discussionmentioning

confidence: 99%

“…Production of CTX-M-type ESBLs was confirmed with the CTX-M-MULTI (V2) lateral-flow immunoassay according to the manufacturer’s instructions (NG Biotech) ( 7 ). Due to known possible cross-reactivity of intrinsic OXY-1-type β-lactamases with monoclonal antibodies contained in the CTX-M-MULTI assay, this test was not performed with K. oxytoca isolates ( 15 ).…”

Section: Methodsmentioning

confidence: 99%

Detection of Extended-Spectrum β-Lactamases (ESBLs) and AmpC in Class A and Class B Carbapenemase-Producing Enterobacterales

Imkamp¹,

Kolesnik-Goldmann²,

Bodendoerfer³

et al. 2022

Microbiol Spectr

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“…In countries where the prevalence of other-than-CTX-M-type ESBL enzymes is important such as those from Asia, South America, or Middle East, the Rapid ESBL NP® offers the advantage to detect any kind of ESBL producers. In addition, one shall be aware that false detection of ESBL has been noted by using the NG CTX-M MULTI® assay for several K. oxytoca strains that possess specific naturally occurring ESBLs of OXY type [30]. All the tests evaluated are low cost and require no specialized equipment or personnel; further studies on cost-benefit analysis are needed however.…”

Section: Discussionmentioning

confidence: 99%

Direct detection of extended-spectrum-β-lactamase-producers in Enterobacterales from blood cultures: a comparative analysis

Boattini

Bianco

Comini

et al. 2021

Eur J Clin Microbiol Infect Dis

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Accurate detection of extended-spectrum-β-lactamase (ESBL)-producing Enterobacterales from bloodstream infection (BSI) is of paramount importance for both epidemiological and clinical purposes, especially for optimization of antibiotic stewardship interventions. Three phenotypic methods for the detection of ESBL phenotype in Klebsiella pneumoniae and Escherichia coli BSI were compared over a 4-month period (May-August 2021) in a main University Hospital from Northern Italy. The methods were the biochemical Rapid ESBL NP®, the immunological NG-Test CTX-M MULTI®, and the E-test technique based on ESBL E-test®. One hundred forty-two blood cultures (BCs) positive for K. pneumoniae or E. coli were included. ESBL and carbapenemase phenotype were detected in 26.1% (n = 37) and 16.9% (n = 24), respectively. The Rapid ESBL NP®, NG-Test CTX-M MULTI®, and direct ESBL E-test® positive and negative predictive values with 95% confidence intervals were 1 (0.87-1) and 0.97 (0.92-0.99), 1 (0.87-1) and 0.97 (0.92-0.99), and 1 (0.88-1) and 1 (0.96-1), respectively. The three phenotypic methods evaluated showed good performance in the detection of ESBL phenotype from K. pneumoniae-or E. coli-positive BCs. Rapid ESBL NP® and NG-test CTX-M® offer the important advantage of a turnaround time of 15 to 45 min, and the Rapid ESBL NP test in addition detects any type of ESBL producers.

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False Immunological Detection of CTX-M Enzymes in Klebsiella oxytoca

Abstract: The global spread of extended-spectrum-β-lactamase (ESBL) is a matter of great concern given high morbidity and mortality associated with invasive infections.…

Cited by 8 publications

References 12 publications

Evaluation of a Lateral Flow Immunoassay for Rapid Detection of CTX-M Producers from Blood Cultures

Evaluation of a Lateral Flow Immunoassay for Rapid Detection of CTX-M Producers from Blood Cultures

Detection of Extended-Spectrum β-Lactamases (ESBLs) and AmpC in Class A and Class B Carbapenemase-Producing Enterobacterales

Direct detection of extended-spectrum-β-lactamase-producers in Enterobacterales from blood cultures: a comparative analysis

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