Comparison of the Modified-Hodge test, Carba NP test, and carbapenem inactivation method as screening methods for carbapenemase-producing  Enterobacteriaceae

Yamada, Kageto; Kashiwa, Machiko; Arai, Katsumi; Nagano, Noriyuki; Saito, Ryoichi

doi:10.1016/j.mimet.2016.06.019

Cited by 45 publications

(28 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, the CIM was described as a highly sensitive and specific assay for the detection of CP-CRE (6,9,18,19). In contrast to these preliminary reports, we identified limited sensitivity of the CIM for detecting both NDM and OXA-48-type producers.…”

Section: Discussioncontrasting

confidence: 73%

Comparison of 11 Phenotypic Assays for Accurate Detection of Carbapenemase-Producing Enterobacteriaceae

et al. 2017

View full text Add to dashboard Cite

Early identification of carbapenemase-producing Enterobacteriaceae (CPE) is essential to prevent their dissemination within health care settings. Our objective was to evaluate the accuracy of 11 phenotypic assays for the detection of CPE. Two collections of carbapenem-resistant Enterobacteriaceae (CRE) isolates were evaluated, including 191 retrospective isolates (122 CP-CRE and 69 non-CP isolates) as well as 45 prospective clinical isolates (15 CP-CRE and 30 non-CP-CRE) obtained over a 3-month period. The sensitivity and specificity of each test was determined, with molecular genotype serving as the gold standard. Among the retrospective cohort, sensitivities ranged from 72% for the boronic acid synergy test for the detection of KPC producers to Ն98% for the modified Carba NP, the Rapidec Carba NP, the manual Blue Carba, and the modified carbapenem inactivation method for the detection of any CPE. Sensitivity differed among tests across enzyme classes. All assays had excellent specificity exceeding 95%, with the exception of the boronic acid synergy test (88%) and modified Hodge test (91%). Prospectively, 45 CRE isolates were encountered over a 3-month period, including 15 CPE (33%) and 30 non-CP-CRE (67%). Results from the prospective cohort were similar. However, a decrease in specificity was observed across most tests, likely due to restricted inclusion of non-CP-CRE to assess the specificity of the assays. Overall, accuracy of CPE detection varied across phenotypic tests. Local epidemiology of CP genotypes, turnaround time, and ease of incorporation into the laboratory workflow should be considered when selecting a phenotypic assay for clinical use.KEYWORDS carbapenem-resistant organisms, carbapenemase-producing organisms, prevalence C arbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE) are associated with significant morbidity and mortality (1, 2). A variety of carbapenemase genes have been described that are either plasmid or chromosomally encoded, including bla KPC , bla SME , bla IMI , bla NDM , bla VIM , bla IMP , and bla OXA-48-type (2). Early and accurate identification of CP-CRE is essential to prevent their dissemination within health care settings.Detection of CP-CRE in clinical laboratories is challenging, as isolates may only have moderate reductions in susceptibilities to carbapenems (3), and resistance may be mediated by other mechanisms, such as extended-spectrum-␤-lactamase (ESBL) and/or AmpC ␤-lactamase producers with decreased membrane permeability. Molecular methods for the detection of carbapenemase genes are costly, may require significant expertise, and are limited by the targets included. Thus, rapid and affordable phenotypic assays to broadly classify CRE into CP-CRE versus non-CP-CRE have been developed.

show abstract

Section: Discussioncontrasting

confidence: 73%

Comparison of 11 Phenotypic Assays for Accurate Detection of Carbapenemase-Producing Enterobacteriaceae

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The test was straightforward to perform and interpret and involved low-cost materials already readily available in clinical laboratories (24). Three early independent comparisons of the CIM to the Carba NP test found the CIM to be an accurate method for the detection of CP-CRE, with equal or better sensitivity for the detection of OXA-48-type carbapenemases in Enterobacteriaceae (25)(26)(27). However, other investigations have found the CIM to have lower detection rates of the OXA-48-type carbapenemases, with reported sensitivities of 80%, 50%, and 91% ( Thomson, unpublished data).…”

mentioning

confidence: 99%

Modified Carbapenem Inactivation Method for Phenotypic Detection of Carbapenemase Production among Enterobacteriaceae

et al. 2017

View full text Add to dashboard Cite

The ability of clinical microbiology laboratories to reliably detect carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE) is an important element of the effort to prevent and contain the spread of these pathogens and an integral part of antimicrobial stewardship. All existing methods have limitations. A new, straightforward, inexpensive, and specific phenotypic method for the detection of carbapenemase production, the carbapenem inactivation method (CIM), was recently described. Here we describe a two-stage evaluation of a modified carbapenem inactivation method (mCIM), in which tryptic soy broth was substituted for water during the inactivation step and the length of this incubation was extended. A validation study was performed in a single clinical laboratory to determine the accuracy of the mCIM, followed by a nine-laboratory study to verify the reproducibility of these results and define the zone size cutoff that best discriminated between CP-CRE and members of the family Enterobacteriaceae that do not produce carbapenemases. Bacterial isolates previously characterized through whole-genome sequencing or targeted PCR as to the presence or absence of carbapenemase genes were tested for carbapenemase production using the mCIM; isolates with Ambler class A, B, and D carbapenemases, non-CP-CRE isolates, and carbapenem-susceptible isolates were included. The sensitivity of the mCIM observed in the validation study was 99% (95% confidence interval [95% CI], 93% to 100%), and the specificity was 100% (95% CI, 82% to 100%). In the second stage of the study, the range of sensitivities observed across nine laboratories was 93% to 100%, with a mean of 97%; the range of specificities was 97% to 100%, with a mean of 99%. The mCIM was easy to perform and interpret for Enterobacteriaceae, with results in less than 24 h and excellent reproducibility across laboratories.

show abstract

“…Thus, IMP producers are often overlooked in clinical laboratories and are also a major problem at medical institutions (18)(19)(20). The CIM has been evaluated worldwide by methods similar to those used in our study (21)(22)(23). Some papers have pointed out that the CIM cannot detect some portion of carbapenemase producers or bacterial species, and several modified CIMs have been reported (24,25).…”

mentioning

confidence: 99%

Suitability of Carbapenem Inactivation Method (CIM) for Detection of IMP Metallo-β-Lactamase-Producing Enterobacteriaceae

et al. 2017

View full text Add to dashboard Cite

Carbapenem-resistant Enterobacteriaceae (CRE) strains have become globally distributed in the past decade, resulting in concern over the control of hospital infections and antimicrobial therapies (1, 2). The majority of CRE isolates are carbapenemase-producing Enterobacteriaceae (CPE) strains, so early detection of CPE strains is essential for providing optimal antimicrobial therapies and preventing horizontal transmission. In 2015, van der Zwaluw et al. reported the carbapenem inactivation method (CIM), a new method for detecting carbapenemase producers with high sensitivity and specificity (3). However, it was unclear whether CIM can identify IMP producers with a low carbapenem MIC or non-CPE strains that are highly carbapenem resistant. In this study, we evaluated whether CIM can identify CPE strains independently of their carbapenem MICs.Were used 233 CPE and 51 non-CPE strains isolated in general hospitals across Japan from 2012 to 2016 and stocked in our laboratory. The strains were collected from blood, sputum, wounds, urine, and feces. Their antibiotic susceptibilities were determined by the agar dilution method in accordance with the recommendations of the CLSI (4). The CPE strains included 191 IMP, 20 KPC, 17 NDM, and 5 OXA-48-like (OXA-48 and OXA-244) producers. The non-CPE strains included 31 extended-spectrum beta-lactamase (CTX-M, SHV, and TEM) producers and 5 plasmid-mediated AmpC ␤-lactamase (DHA, CMY, and CFE) producers. They were identified by DNA sequence amplification as previously described (5-10). Of the non-CPE strains, 13 highly carbapenem-resistant strains were identified as producing cephalosporinases and lacking porin function by SDS-PAGE, DNA sequencing, and quantitative reverse transcription-PCR (11).The CIM was conducted as previously described (3). The isolates were cultured on Mueller-Hinton agar (MHA) plates. A full 10-l inoculation loop of each strain was suspended in 400 l of sterile distilled water, and a 10-g meropenem (MEM) susceptibilitytesting disk (E-DF85; EIKEN) was immersed in the solution. After incubation at 35°C for 2 h, the disk was removed and placed on an MHA plate inoculated with a 0.5 McFarland standard of Escherichia coli strain ATCC 25922 with a sterile cotton swab. Finally, the plate was incubated overnight at 35°C and the inhibition zone around each disk was measured. Inhibition circles Ͻ10 mm in diameter were judged to indicate CIM positivity.The CIM showed a sensitivity of 100% (233/233) for CPE strains and a specificity of 96.1% (49/51) for non-CPE strains (Table 1). The MICs of MEM for the 191 IMP producers ranged from 0.125 to 32 g/ml (MIC 50 ϭ 0.5 g/ml, MIC 90 ϭ 2 g/ml), and those of imipenem (IPM) ranged from 0.06 to 8 g/ml (MIC 50 ϭ 0.125 g/ml, MIC 90 ϭ 0.5

show abstract

Comparison of the Modified-Hodge test, Carba NP test, and carbapenem inactivation method as screening methods for carbapenemase-producing Enterobacteriaceae

Cited by 45 publications

References 8 publications

Comparison of 11 Phenotypic Assays for Accurate Detection of Carbapenemase-Producing Enterobacteriaceae

Comparison of 11 Phenotypic Assays for Accurate Detection of Carbapenemase-Producing Enterobacteriaceae

Modified Carbapenem Inactivation Method for Phenotypic Detection of Carbapenemase Production among Enterobacteriaceae

Suitability of Carbapenem Inactivation Method (CIM) for Detection of IMP Metallo-β-Lactamase-Producing Enterobacteriaceae

Contact Info

Product

Resources

About