No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Evaluation of the rapid biochemical β-CARBA™ test for detection of carbapenemase-producing Gram-negative bacteria
Abstract
We evaluated a rapid biochemical screening test β-CARBA™ for detection of Gram-negative carbapenemase producers. The sensitivity of the test after 30min incubation was 98.2%, but increased to 100% after 1h. β-CARBA™ proved reliable for carbapenemase screening in Acinetobacter spp. for which currently no commercial phenotypic assays are available.
... A number of phenotypic methods to detect carbapenemase activity have been developed. These include the modified Hodge test (MHT) (139), the Carba NP (CNP) test (140) and its variants, the -Carba test (141,142), the carbapenem inactivation method (CIM) (143), the modified carbapenem inactivation method (mCIM) (144), matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) (145), isothermal titration calorimetry (ITC) (146), and UV spectrophotometry (147). The MHT, CNP, and mCIM have been extensively evaluated, and the latter two are currently recommended by the CLSI for detecting carbapenemases in carbapenemase-producing Enterobacteriaceae (CPE) and carbapenemase-producing P. aeruginosa (148). ...
... The CarbAcineto NP test is a modified CNP protocol, using modified lysis conditions and an increased bacterial inoculum to detect all types of carbapenemases, with 88.9% to 94.7% sensitivity and 100% specificity for Acinetobacter (162,163). Several variants of CNP with simplified procedures have become commercially available, including Rapidec Carba NP (bioMérieux) (141,164,165), Neo-Rapid Carb (Rosco Diagnostica) (153,164), Rapid Blue Carb (Rosco Diagnostica) (166), and -Carba (Bio-Rad) (141,142). Rapidec Carba NP and Neo-Rapid Carb have overall comparable sensitivity and specificity compared with CNP (141,153,164,165), while it has been reported that Rapid Blue Carb (166) and -Carba (141, 142) may be slightly less sensitive. ...
New Delhi metallo-β-lactamase (NDM) is a metallo-β-lactamase able to hydrolyze almost all β-lactams. Twenty-four NDM variants have been identified in >60 species of 11 bacterial families, and several variants have enhanced carbapenemase activity. Klebsiella pneumoniae and Escherichia coli are the predominant carriers of blaNDM, with certain sequence types (STs) (for K. pneumoniae, ST11, ST14, ST15, or ST147; for E. coli, ST167, ST410, or ST617) being the most prevalent. NDM-positive strains have been identified worldwide, with the highest prevalence in the Indian subcontinent, the Middle East, and the Balkans. Most blaNDM-carrying plasmids belong to limited replicon types (IncX3, IncFII, or IncC). Commonly used phenotypic tests cannot specifically identify NDM. Lateral flow immunoassays specifically detect NDM, and molecular approaches remain the reference methods for detecting blaNDM Polymyxins combined with other agents remain the mainstream options of antimicrobial treatment. Compounds able to inhibit NDM have been found, but none have been approved for clinical use. Outbreaks caused by NDM-positive strains have been reported worldwide, attributable to sources such as contaminated devices. Evidence-based guidelines on prevention and control of carbapenem-resistant Gram-negative bacteria are available, although none are specific for NDM-positive strains. NDM will remain a severe challenge in health care settings, and more studies on appropriate countermeasures are required.
... This may delay optimal antimicrobial treatment of the causative pathogen [18]. Rapid methods for identification of bacteria and antimicrobial susceptibility testing such as methods based on Nucleic Acid Amplification Technology (NAAT) or on Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight mass spectrometry (MALDI-TOF) provide results within minutes to hours and can in some cases be applied directly to patient samples, thereby bypassing time demanding culture steps [19][20][21][22]. The knowledge of causative bacteria and of possible presence or absence of resistance points to the possible source of infection and allows for fast optimization and optimal duration of antibiotic treatment. ...
The incidence of infections caused by bacteria that are resistant to antibiotics is constantly increasing. In Europe alone, it has been estimated that each year about 33′000 deaths are attributable to such infections. One important driver of antimicrobial resistance is the use and abuse of antibiotics in human medicine. Inappropriate prescribing of antibiotics is still very frequent: up to 50% of all antimicrobials prescribed in humans might be unnecessary and several studies show that at least 50% of antibiotic treatments are inadequate, depending on the setting. Possible strategies to optimize antibiotic use in everyday clinical practice and to reduce the risk of inducing bacterial resistance include: the implementation of rapid microbiological diagnostics for identification and antimicrobial susceptibility testing, the use of inflammation markers to guide initiation and duration of therapies, the reduction of standard durations of antibiotic courses, the individualization of antibiotic therapies and dosing considering pharmacokinetics/pharmacodynamics targets, and avoiding antibiotic classes carrying a higher risk for induction of bacterial resistance. Importantly, measures to improve antibiotic prescribing and antibiotic stewardship programs should focus on facilitating clinical reasoning and improving prescribing environment in order to remove any barriers to good prescribing.
... As phenotypic susceptibility tests (such as AST-DETECT) rely on growth, they can identify resistance irrespective of an organism's genotype, including resistance caused by uncommon or previously uncharacterized resistance determinants, in addition to resistance resulting from efflux or porin loss (Bard and Lee 2018). In comparison to approved β-lactamase detection systems such as the RAPIDEC CARBA NP test, AST-DETECT does not need to be used in conjunction with other tests to achieve extended AST information (Hinić et al. 2018;WHO 2019). The AST-DETECT assay also requires minimal equipment (shaking incubator and device capable of reading absorbance), can be adapted to an automated format and since there is a binary 'yes/no' readout for resistance, specialist training is not required to interpret AST results. ...
The increasing prevalence of extended spectrum β-lactamases (ESBLs) and plasmid-mediated AmpC (pAmpC) β-lactamases among Enterobacterales threatens our ability to treat urinary tract infections (UTIs). These organisms are resistant to most β-lactam antibiotics and are frequently multidrug-resistant (MDR). Consequently, they are often resistant to antibiotics used to empirically treat UTIs. The lack of rapid diagnostic and antibiotic susceptibility tests (AST) makes clinical management of UTIs caused by such organisms difficult, as standard culture and susceptibility assays require several days. We have adapted a biochemical detection assay, termed dual-enzyme trigger-enabled cascade technology (DETECT) for rapid detection of resistance (time-to-result of 3 h) to other antibiotics commonly used in treatment of UTIs. DETECT is activated by the presence of CTX-M and pAmpC β-lactamases. In this proof-of-concept study, the adapted DETECT assay (AST-DETECT) has been performed on pure-cultures of Klebsiella pneumoniae and Escherichia coli (48 isolates) expressing ESBL or pAmpC β-lactamases to perform AST for ciprofloxacin (sensitivity 96.9%, specificity 100%, accuracy 97.9%) nitrofurantoin (sensitivity 95.7%, specificity 91.7%, accuracy 94%) and trimethoprim/sulfamethoxazole (sensitivity 83.3%, specificity 100%, accuracy 89.4%). These results suggest that AST-DETECT may be adapted as a potential diagnostic platform to rapidly detect multidrug-resistant E. coli and K. pneumoniae that cause UTI.
... However, a prolonged incubation time leads to a decrease in specificity. A color change from yellow to red or orange indicates a positive result 73,74 . ...
Multidrug resistance is growing at an alarming rate among a variety of bacterial species, causing infections, which threaten the lives of patients. Detection of metal-β-lactamase producers (IMP, VIM, NDM) and of KPC producers may be based on the inhibitory properties of several molecules but requires additional expertise and time. Several authors describe the use of new rapid identification methods.
The aim of our review is to revise the new rapid methods for the detection of carbapenemases and their identification by Gram-negative bacilli.
Introduction:
The Carba NP test is a biochemical chromogenic assay developed to detect carbapenemase activity. Variable performance has been reported according to the type of carbapenemase and bacterial species involved. We aimed to describe the benefit of the Carba NP test and its commercial version, the RAPIDEC® CARBA NP, to detect carbapenemase-producing Pseudomonas aeruginosa.
Methods:
PubMed and ScienceDirect databases were searched. The following data was collected from each included study: research protocol, molecular profile of the tested strains, and sensitivity and specificity of the test used to detect carbapenemase-producing P. aeruginosa.
Results:
Thirty-four studies were included. The most frequently tested strains were metallo-beta-lactamase producers. The pooled sensitivity to detect carbapenemase-producing P. aeruginosa with the original Carba NP test, the Clinical and Laboratory Standards Institute (CLSI) Carba NP test, and the RAPIDEC® CARBA NP was 92%, 95%, and 96%, respectively. The pooled specificity was 99% with the original and the CLSI Carba NP tests, and 92% with the RAPIDEC® CARBA NP. Several studies evaluated modified versions of the Carba NP test to detect carbapenemase-producing P. aeruginosa, with reported sensitivity and specificity exceeding 90% in most cases.
Conclusion:
The Carba NP test allows for fast screening and easy handling as well as optimal performance to detect carbapenemase-producing P. aeruginosa. These findings should be confirmed by further studies including a larger cohort of isolates and various types of carbapenemases, mainly non-metallo-beta-lactamases.
Objectives:
There is an urgent need for accurate and fast diagnostic tests to identify carbapenemase-producing bacteria. Here, we have evaluated a novel colorimetric test (the β-CARBA™ test; Bio-Rad) to detect carbapenemase-producing Gram-negative bacilli from cultured colonies.
Methods:
The performance of the β-CARBA™ test was compared with that of the Carba NP test (or the CarbAcineto NP test) and RAPIDEC ® CARBA NP (bioMérieux) using a collection of 290 isolates with characterized β-lactamase content. This collection included 199 carbapenemase producers (121 Enterobacteriaceae, 36 Pseudomonas and 42 Acinetobacter baumannii ) and 91 non-carbapenemase producers (55 Enterobacteriaceae, 20 Pseudomonas and 16 A. baumannii ).
Results:
The β-CARBA™ test correctly detected 84.9% of the carbapenemase producers, including all KPC and IMP, 96.4% of VIM, 85.3% of NDM, 80.5% of OXA-48-like and 91.2% of A. baumannii -related OXA carbapenemases (OXA-23, OXA-40, OXA-58, OXA-143 and overexpressed OXA-51). All rare metallo-β-lactamases (SPM, AIM, GIM, DIM and SIM) were detected. Importantly, all non-KPC Ambler class A carbapenemases were not detected, including GES variants with carbapenemase activity ( n = 6), IMI ( n = 3), NMC-A ( n = 1), SME ( n = 2), FRI-1 ( n = 1) and BIC-1 ( n = 1). All non-carbapenemase producers gave a negative result except with OXA-163-, OXA-405- and one TEM-3-producing Citrobacter freundii . The overall sensitivity and specificity of the β-CARBA™ test were 84.9% and 95.6%, respectively. This test is easy to perform and to interpret by non-specialized staff members.
Conclusions:
Despite lack of specificity towards non-KPC Ambler class A and OXA-48-like carbapenemases, the β-CARBA™ test could complete the existing panel of tests available for the confirmation of carbapenemases in Gram-negatives.
The novel biochemical test, the Rapid Carba NP (RCNP), was evaluated using carbapenemase- and non-carbapenemase-producing
Enterobacteriaceae isolates. The RCNP was compared with the Carba NP test (CNP) and the Modified Hodge's test. Compared to the CNP test, the
RCNP test had identical sensitivity (96%) and lower specificity (93%, vs. 100%). The medium used to culture the isolates significantly
affected test sensitivity and specificity. The RCNP test was quicker and easier to perform than the other tests.
Recently BioMérieux, France has introduced RAPIDEC CARBA NP test kit for rapid detection of carbapenemase producing Gram Negative
bacteria. The same was evaluated in this study and we report a sensitivity, specificity, positive and negative predictive
values as 92.6%, 96.2%, 95.83 % and 92.6% respectively.The test was easy to perform and interpret, relatively less expensive
(5$/Rs 300 per test) and provides a practical solution for early detection of carbapenemase producing multidrug resistant
Gram Negative bacteria.
The accurate detection of carbapenemase-producing organisms is a major challenge for clinical laboratories. The Carba NP test is highly accurate but inconvenient as it requires frequent preparation of fresh imipenem solution. The current study was designed to compare the Carba NP test to two alternative tests for accuracy and convenience. These were a modified Carba NP test that utilized intravenous (IV) imipenem/cilastatin, which is cheaper than reference standard imipenem powder, and an updated version of the Rosco Neo-Rapid CARB Kit, which does not require the preparation of imipenem solution and has a shelf-life of 2 years. The comparison included 87 isolates that produced class A carbapenemases including KPC-2, 3, 4, 5, 6, 8, NMC-A, SME type, 40 isolates that produced metallo-β-lactamases including NDM-1, GIM-1, SPM-1, IMP-1, 2, 7, 8, 18, 27, VIM-1, 2, 7, 11 isolates that produced OXA-48 and one isolate that produced OXA-181. Negative controls consisted of 50 isolates that produced ESBLs, AmpCs (including hyperproducers), K1, other broad spectrum β-lactamases and porin and efflux mutants. Each test exhibited 100% specificity and high sensitivity (Carba NP 100%, Rosco 99% using modified interpretation guidelines), and modified Carba NP 96%). A modified approach to interpretation of the Rosco test was necessary to achieve the sensitivity of 99%. If the accuracy of the modified interpretation is confirmed, the Rosco test is an accurate and more convenient alternative to the Carba NP test.
Copyright © 2015, American Society for Microbiology. All Rights Reserved.
The objective of this study was the evaluation of the performance of two commercially available biochemical tests for the rapid detection of carbapenemase-producing Enterobacteriaceae compared with a home-made technique.
A collection of 150 enterobacterial isolates, including 132 isolates with decreased susceptibility to at least one carbapenem molecule, were tested for carbapenemase activity using the RAPIDEC(®) CARBA NP (bioMérieux), the Rapid CARB Screen(®) (Rosco Diagnostica) and the home-made Carba NP test. This strain collection included 55 non-carbapenemase producers, 21 KPC producers, 21 NDM producers, 17 VIM producers, 11 IMP producers, 16 OXA-48 producers and 9 OXA-48-like producers (OXA-162, OXA-181, OXA-204, OXA-232 and OXA-244).
The RAPIDEC(®) CARBA NP detected all carbapenemase producers except a single OXA-244 producer. Using the Rapid CARB Screen(®), one KPC-2, two NDM-1, one OXA-48 and five OXA-48 variant producers gave equivocal results and one OXA-244 producer was not detected. Using the Carba NP test, the same OXA-244 producer was not detected and one OXA-181 producer and one OXA-244 producer gave equivocal results. Sensitivity and specificity were 99% (95% CI 94.3%-99.8%) and 100% (95% CI 93.5%-100%), respectively, for the RAPIDEC(®) CARBA NP test, 89.5% (95% CI 81.7%-94.2%) and 70.9% (95% CI 57.9%-81.2%) for the Rapid CARB Screen(®) and 96.8% (95% CI 91.1%-98.9%) and 100% (95% CI 93.5%-100%) for the Carba NP test. The impact of the use of an adequate bacterial inoculum for obtaining the optimal performance with the RAPIDEC(®) CARBA NP was noted.
The RAPIDEC(®) CARBA NP possesses the best performance for rapid and efficient detection of carbapenemase-producing Enterobacteriaceae.
© The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
Carbapenem resistance in Acinetobacter baumannii is a growing public health concern and is most often mediated by OXA carbapenemases. We describe a novel multiplex polymerase chain reaction (PCR) assay able to detect and distinguish alleles encoding three subgroups of acquired OXA carbapenemases (OXA-23-like, OXA-24-like and OXA-58-like) that are scattered in Acinetobacter spp., and a fourth subgroup, OXA-51-like, which appears to be intrinsic to Acinetobacter baumannii. Isolates belonging to two prevalent UK A. baumannii 'OXA' clones (OXA-23 clones 1 and 2) had alleles encoding both an intrinsic OXA-51-like and an acquired OXA-23 enzyme, whereas isolates of the 'SE clone' had only an intrinsic bla(OXA-51-like) allele. Genes encoding OXA-58 were detected (with bla(OXA-51-like)) in a cluster of related isolates from a single hospital. This simple assay will assist in monitoring the mechanisms responsible for carbapenem resistance in Acinetobacter spp.
bla(OXA-51-like) was sought in clinical isolates of Acinetobacter species in a multiplex PCR, which also detects bla(OXA-23-like) and class 1 integrase genes. All isolates that gave a band for bla(OXA-51-like) identified as A. baumannii. This gene was detected in each of 141 isolates of A. baumannii but not in those of 22 other Acinetobacter species.
We evaluated RAPIDEC® CARBA NP, Neo-Rapid CARB, chromID® CARBA SMART (CARB/OXA), Brilliance™ CRE/ESBL, ChromArt CRE and BBL™ CHROMagar™ CPE for the detection of carbapenemase-producing bacteria. The analytical sensitivity of RAPIDEC® CARBA NP was better than that of Neo-Rapid CARB. A combination of carbapenemase and ESBL screening plates could be advantageous.
Objectives:
We evaluated the RAPIDEC(®) CARBA NP assay (bioMérieux SA, Marcy-l'Étoile, France), a colorimetric test for rapid detection of carbapenemases, at two sites: Karolinska University Laboratory and PHE's national reference laboratory.
Methods:
A total of 138 bacterial isolates previously characterized as positive for class A, B and/or D carbapenemase genes and 138 supposed non-carbapenemase producers were tested with RAPIDEC(®) CARBA NP according to the manufacturer's protocol. Two carbapenemase-producing isolates carried both NDM and OXA-48-like genes. Molecular detection of the expected carbapenemase gene(s) was used as the gold standard, and was performed by conventional and real-time PCR in-house assays.
Results:
The RAPIDEC(®) CARBA NP assay detected 135 of 138 carbapenemase producers; one OXA-48-producing Klebsiella pneumoniae and two Acinetobacter baumannii producing OXA-23 or OXA-24 were not detected. Among 'negative' controls, 135 of 138 isolates were negative by RAPIDEC(®) CARBA NP. The exceptions were one Klebsiella oxytoca, which was later found to produce GES-5 carbapenemase, one Pseudomonas aeruginosa with OprD loss and increased efflux, and one Enterobacter cloacae with impermeability. When numbers were adjusted for the GES-5 producer, the overall sensitivity of the RAPIDEC(®) CARBA NP test was 97.8% and its specificity was 98.5%.
Conclusions:
The assay took less than 2.5 h to carry out, was user-friendly and had a high overall performance, making it an attractive option for clinical laboratories.
