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Gill CM, Rajkotia P, Roberts AL, Tenover FC, Nicolau DP. Directed carbapenemase testing is no longer just for Enterobacterales: cost, labor, and workflow assessment of expanding carbapenemase testing to carbapenem-resistant P. aeruginosa. Emerg Microbes Infect 2023; 12:2179344. [PMID: 36786132 PMCID: PMC9980414 DOI: 10.1080/22221751.2023.2179344] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Molecular carbapenem-resistance testing, such as for the presence of carbapenemases genes, is commonly implemented for the detection of carbapenemase-producing Enterobacterales. Carbapenemase-producing P. aeruginosa is also associated with significant morbidity and mortality, although; prevalence may be underappreciated in the United States due to a lack of carbapenemase testing. The present study sought to compare hands-on time, cost and workflow implementation of carbapenemase gene testing in Enterobacterales and P. aeruginosa isolates versus sending out isolates to a public health laboratory (PHL) for testing to assess if in-house can provide actionable results. The time to carbapenemase gene results were compared. Differences in cost for infection prevention measures were extrapolated from the time of positive carbapenemase gene detection in-house versus PHL. The median time to perform carbapenemase gene testing was 7.5 min (range 5-14) versus 10 min (range 8-22) for preparation to send isolates to the PHL. In-house testing produced same day results compared with a median of 6 days (range 3-14) to receive results from PHL. Cost of in-house testing and send outs were similar ($46.92 versus $40.53, respectively). If contact precautions for patients are implemented until carbapenemase genes are ruled out, in-house testing can save an estimated $76,836.60 annually. Extension of in-house carbapenemase testing to include P. aeruginosa provides actionable results 3-14 days earlier than PHL Standard Pathway testing, facilitating guided therapeutic decisions and infection prevention measures. Supplemental phenotypic algorithms can be implemented to curb the cost of P. aeruginosa carbapenemases testing by identifying isolates most likely to harbour carbapenemases.
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Affiliation(s)
- Christian M. Gill
- Center for Anti-Infective Research & Development Hartford Hospital, Hartford, CT, USA, Christian M. Gill Center for Anti-Infective Research & Development Hartford Hospital, Hartford, CT, USA
| | - Poonam Rajkotia
- Microbiology Laboratory Services, Hartford Healthcare Ancillary Microbiology Laboratory, Newington, CT, USA
| | - Amity L. Roberts
- Microbiology Laboratory Services, Hartford Healthcare Ancillary Microbiology Laboratory, Newington, CT, USA
| | | | - David P. Nicolau
- Center for Anti-Infective Research & Development Hartford Hospital, Hartford, CT, USA,Department of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
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Khoo BY, Hon PY, Leong J, Sai Rama Sridatta P, Thevasagayam NM, Loy SQD, Chua JJY, Ang BSP, Chow A, Marimuthu K, De PP, Ng OT, Vasoo S. Evaluation of NG-Test CARBA 5 version 2, Cepheid Xpert Carba-R, and carbapenem inactivation methods in comparison to whole-genome sequencing for the identification of carbapenemases in non-fermenting Gram-negative bacilli. J Clin Microbiol 2023; 61:e0031623. [PMID: 37671882 PMCID: PMC10512785 DOI: 10.1128/jcm.00316-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 07/11/2023] [Indexed: 09/07/2023] Open
Abstract
NG-Test CARBA 5 (NG-Biotech) is a rapid in vitro multiplex immunoassay for the phenotypic detection and differentiation of the "big five" carbapenemase families (KPC, OXA-48-like, VIM, IMP, and NDM). Version 2 of this assay was evaluated alongside the Xpert Carba-R assay (Cepheid, Inc.), the modified carbapenem inactivation method (mCIM), and the CIMTris assay, with a collection of carbapenem-resistant non-fermenting Gram-negative bacilli comprising 138 Pseudomonas aeruginosa and 97 Acinetobacter baumannii isolates. Whole-genome sequencing (WGS) was used as the reference standard. For P. aeruginosa, NG-Test CARBA 5 produced an overall percentage agreement (OPA) with WGS of 97.1%, compared with 92.8% forXpert Carba-R and 90.6% for mCIM. For A. baumannii, as OXA-type carbapenemases (non-OXA-48) are not included, both the NG-Test CARBA 5 and Xpert Carba-R only had an OPA of 6.2%, while the CIMTris performed well with an OPA of 99.0%. The majority of A. baumannii isolates (95.9%) tested falsely positive for IMP on NG-Test CARBA 5; no IMP genes were found on WGS. No clear cause was found for this phenomenon; a cross-reacting protein antigen unique to A. baumannii is a possible culprit. NG-Test CARBA 5 performed well for carbapenemase detection in P. aeruginosa. However, results from A. baumannii isolates should be interpreted with caution.
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Affiliation(s)
- Bo Yan Khoo
- National Centre for Infectious Diseases, Singapore
- Department of Infectious Diseases, Tan Tock Seng Hospital, , Singapore
| | - Pei Yun Hon
- Infectious Diseases Research Laboratory, National Centre for Infectious Diseases, , Singapore
| | - Janice Leong
- Department of Laboratory Medicine, Tan Tock Seng Hospital, , Singapore
| | | | | | - Song Qi Dennis Loy
- Infectious Diseases Research Laboratory, National Centre for Infectious Diseases, , Singapore
| | - Jasmine J. Y. Chua
- Infectious Diseases Research Laboratory, National Centre for Infectious Diseases, , Singapore
| | - Brenda Sze Peng Ang
- National Centre for Infectious Diseases, Singapore
- Department of Infectious Diseases, Tan Tock Seng Hospital, , Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, , Singapore
- Yong Loo Lin School of Medicine, National University of Singapore, , Singapore
- Department of Infection Prevention and Control, Tan Tock Seng Hospital, , Singapore
| | - Angela Chow
- National Centre for Infectious Diseases, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, , Singapore
- Yong Loo Lin School of Medicine, National University of Singapore, , Singapore
- Department of Preventive and Population Medicine, Office of Clinical Epidemiology, Analytics, and Knowledge (OCEAN), Tan Tock Seng Hospital, , Singapore
- Saw Swee Hock School of Public Health, National University of Singapore, , Singapore
| | - Kalisvar Marimuthu
- National Centre for Infectious Diseases, Singapore
- Department of Infectious Diseases, Tan Tock Seng Hospital, , Singapore
- Yong Loo Lin School of Medicine, National University of Singapore, , Singapore
| | - Partha Pratim De
- Department of Laboratory Medicine, Tan Tock Seng Hospital, , Singapore
| | - Oon Tek Ng
- National Centre for Infectious Diseases, Singapore
- Department of Infectious Diseases, Tan Tock Seng Hospital, , Singapore
- Infectious Diseases Research Laboratory, National Centre for Infectious Diseases, , Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, , Singapore
| | - Shawn Vasoo
- National Centre for Infectious Diseases, Singapore
- Department of Infectious Diseases, Tan Tock Seng Hospital, , Singapore
- Infectious Diseases Research Laboratory, National Centre for Infectious Diseases, , Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, , Singapore
- Yong Loo Lin School of Medicine, National University of Singapore, , Singapore
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Zhang S, Mi P, Wang J, Li P, Luo K, Liu S, Al-Shamiri MM, Lei J, Lai S, Han B, Chen Y, Han L, Han S. The optimized carbapenem inactivation method for objective and accurate detection of carbapenemase-producing Acinetobacter baumannii. Front Microbiol 2023; 14:1185450. [PMID: 37520356 PMCID: PMC10372451 DOI: 10.3389/fmicb.2023.1185450] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/27/2023] [Indexed: 08/01/2023] Open
Abstract
The modified carbapenem inactivation method (mCIM) recommended by the Clinical and Laboratory Standards Institute is not applicable for detecting carbapenemases in Acinetobacter baumannii. Four currently reported phenotypic detection methods, namely, the modified Hodge test, the mCIM, the adjusted mCIM, and the simplified carbapenem inactivation method (sCIM), did not perform well in our 90 clinical A. baumannii isolates. Thus, the minimal inhibitory concentrations (MICs) of carbapenems and the existence and expression of carbapenemase-encoding genes were detected to explain the results. According to the E-test, which was more accurate than the VITEK 2 system, 80.0 and 41.1% were resistant to imipenem (IPM) and meropenem (MEM), respectively, and 14.4 and 53.3% exhibited intermediate resistance, respectively. Five β-lactamase genes were found, of which blaOXA-51-like, blaTEM, and blaOXA-23-like were detected more frequently in 85 non-susceptible strains. The expression of blaOXA-23-like was positively correlated with the MIC values of IPM and MEM. Therefore, an improved approach based on the mCIM, designated the optimized CIM (oCIM), was developed in this study to detect carbapenemases more accurately and reproducibly. The condition was improved by evaluating the factors of A. baumannii inoculum, incubation broth volume, and MEM disk incubation time. Obvious high sensitivity (92.94%) and specificity (100.00%) were obtained using the oCIM, which was cost-effective and reproducible in routine laboratory work.
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Affiliation(s)
- Sirui Zhang
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Peng Mi
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
- Department of Laboratory Medicine, Shaanxi Provincial People’s Hospital, Xi’an, China
| | - Jingdan Wang
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Pu Li
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Kai Luo
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Shuyan Liu
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Mona Mohamed Al-Shamiri
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Jin’e Lei
- Department of Laboratory Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Simin Lai
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Bei Han
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Yanjiong Chen
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Lei Han
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Shaoshan Han
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi’an Jiaotong University, Xi'an, China
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Gill CM, Aktaþ E, Alfouzan W, Bourassa L, Brink A, Burnham CAD, Canton R, Carmeli Y, Falcone M, Kiffer C, Marchese A, Martinez O, Pournaras S, Satlin M, Seifert H, Thabit AK, Thomson KS, Villegas MV, Nicolau DP. The ERACE-PA Global Surveillance Program: Ceftolozane/tazobactam and Ceftazidime/avibactam in vitro Activity against a Global Collection of Carbapenem-resistant Pseudomonas aeruginosa. Eur J Clin Microbiol Infect Dis 2021; 40:2533-2541. [PMID: 34291323 PMCID: PMC8590662 DOI: 10.1007/s10096-021-04308-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 07/07/2021] [Indexed: 02/08/2023]
Abstract
The cephalosporin-β-lactamase-inhibitor-combinations, ceftolozane/tazobactam and ceftazidime/avibactam, have revolutionized treatment of carbapenem-resistant Pseudomonas aeruginosa (CR-PA). A contemporary assessment of their in vitro potency against a global CR-PA collection and an assessment of carbapenemase diversity are warranted. Isolates determined as CR-PA by the submitting site were collected from 2019-2021 (17 centers in 12 countries) during the ERACE-PA Global Surveillance Program. Broth microdilution MICs were assessed per CLSI standards for ceftolozane/tazobactam, ceftazidime/avibactam, ceftazidime, and cefepime. Phenotypic carbapenemase testing was conducted (modified carbapenem inactivation method (mCIM)). mCIM positive isolates underwent genotypic carbapenemase testing using the CarbaR, the CarbaR NxG, or whole genome sequencing. The MIC50/90 was reported as well as percent susceptible (CLSI and EUCAST interpretation). Of the 807 isolates, 265 (33%) tested carbapenemase-positive phenotypically. Of these, 228 (86%) were genotypically positive for a carbapenemase with the most common being VIM followed by GES. In the entire cohort of CR-PA, ceftolozane/tazobactam and ceftazidime/avibactam had MIC50/90 values of 2/ > 64 and 4/64 mg/L, respectively. Ceftazidime/avibactam was the most active agent with 72% susceptibility per CLSI compared with 63% for ceftolozane/tazobactam. For comparison, 46% of CR-PA were susceptible to ceftazidime and cefepime. Against carbapenemase-negative isolates, 88 and 91% of isolates were susceptible to ceftolozane/tazobactam and ceftazidime/avibactam, respectively. Ceftolozane/tazobactam and ceftazidime/avibactam remained highly active against carbapenem-resistant P. aeruginosa, particularly in the absence of carbapenemases. The contemporary ERACE-PA Global Program cohort with 33% carbapenemase positivity including diverse enzymology will be useful to assess therapeutic options in these clinically challenging organisms with limited therapies.
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Affiliation(s)
- Christian M Gill
- Center for Anti-Infective Research & Development Hartford Hospital, 80 Seymour Street, Hartford, CT, 06102, USA
| | - Elif Aktaþ
- Clinical Microbiology Laboratory, University of Health Sciences, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
| | - Wadha Alfouzan
- Laboratory Medicine- Farwania Hospital, Ministry of Health, Kuwait, Department of Microbiology, Faculty of Medicine, Kuwait University, Jabriya, Kuwait
| | - Lori Bourassa
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
| | - Adrian Brink
- Division of Medical Microbiology, Department of Pathology, Faculty of Health Sciences, National Health Laboratory Services, University of Cape Town, Cape Town , South Africa
| | | | - Rafael Canton
- Servicio de Microbiologia. Hospital Ramón Y Cajal-IRYCIS, Madrid, Spain
| | - Yehuda Carmeli
- National Institute for Infection Control and Antibiotic Resistance, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel
| | - Marco Falcone
- Infectious Diseases Division, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Carlos Kiffer
- Internal Medicine Department and LEMC-Alerta Lab, Escola Paulista de Medicina, UNIFESP, São Paulo, Brazil
| | - Anna Marchese
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, and Clinical Microbiology Unit, San Martino Policlinico Hospital-IRCCS for Oncology and Neuroscience, Genoa, Italy
| | - Octavio Martinez
- Department of Pathology and Microbiology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Spyros Pournaras
- Laboratory of Clinical Microbiology, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Michael Satlin
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Harald Seifert
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Goldenfelsstrasse 19-21, 50935, Köln, Germany
| | - Abrar K Thabit
- Pharmacy Practice Department, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia
| | | | - Maria Virginia Villegas
- Grupo de Resistencia Antimicrobiana Y Epidemiología Hospitalaria (RAEH), Universidad El Bosque, Bogotá, Colombia
| | - David P Nicolau
- Center for Anti-Infective Research & Development Hartford Hospital, 80 Seymour Street, Hartford, CT, 06102, USA.
- Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA.
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Antibiotic Resistance Pattern of Pseudomonas aeruginosa Isolated from Clinical Specimens from a Tertiary Care Centre in Central Kerala with Special Reference to Carbapenemase Detection. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2021. [DOI: 10.22207/jpam.15.4.34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is inherently resistant to many drugs. It is now an emerging opportunistic pathogen of clinical relevance. The emergence of carbapenemases is another major concern. Initiation of appropriate therapy is of paramount importance thus highlighting the need of active surveillance for newer emerging resistance trends for better infection control. To study the resistance pattern of P. aeruginosa isolates obtained from lab specimens and to determine the production of ESBL and Carbapenemase among them. A hospital-based cross-sectional study was carried out in the Department of Microbiology, Government medical college Thrissur, among P. aeruginosa isolates obtained from lab specimens, from January 2018 – December 2018. 162 isolates were studied. Antimicrobial susceptibility testing was done by Kirby – Bauer disc diffusion method, extended-spectrum beta-lactamase (ESBL) production was confirmed by and phenotypic confirmatory disc diffusion test. Carbapenemase detection was done using the modified carbapenemase inactivation (mCIM) method. The obtained data was analysed. Among 162 isolates 83% were non-multidrug-resistant (MDR) strains and 17% were MDR strains. 22% of ceftazidime resistant isolates were ESBL producers. 6.2% isolates were resistant to imipenem. Among the imipenem resistant isolates, Carbapenemase production was seen in 30% isolates by mCIM test. According to our study, the most effective antibiotic against P. aeruginosa were imipenem and cefoperazone/sulbactam showing resistance in 6.3% and 6.9% isolates respectively. The diversity of antibiotic resistance mechanisms and the emergence of carbapenem resistance is a threat that limits treatment choices. This suggests the need for ongoing antimicrobial susceptibility studies in the future.
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Practical agar-based disk-diffusion tests using sulfamoyl heteroarylcarboxylic acids for identification of subclass B1 metallo-β-lactamase-producing Enterobacterales. J Clin Microbiol 2021; 59:e0076121. [PMID: 34260275 DOI: 10.1128/jcm.00761-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The worldwide distribution of carbapenemase-producing Enterobacterales (CPE) is a serious public health concern as they exhibit carbapenem resistance, thus limiting the choice of antimicrobials for treating CPE infections. The combination treatment with a β-lactam and one of the newly approved β-lactamase inhibitors, such as avibactam, relebactam, or vaborbactam, provides a valuable tool to cope with CPE; however, these inhibitors are active only against serine-type carbapenemases, and not against metallo-β-lactamases (MβLs). Therefore, it is important to readily differentiate carbapenemases produced by CPE by using simple and reliable methods in order to choose an appropriate treatment. Here, we developed three practical agar-based disk-diffusion tests (double-disk synergy test [DDST], disk potentiation test, and modified carbapenem inactivation method [mCIM]) to discriminate the production of subclass B1 MβLs, such as IMP-, NDM-, and VIM-type MβLs, from the other carbapenemases, especially serine-type carbapenemases. This was accomplished using B1 MβL-specific sulfamoyl heteroarylcarboxylic acid inhibitors, 2,5-dimethyl-4-sulfamoylfuran-3-carboxylic acid (SFC) and 2,5-diethyl-1-methyl-4-sulfamoylpyrrole-3-carboxylic acid (SPC), originally developed by us. The DDST and mCIM using SFC and SPC revealed high sensitivity (95.3%) and specificity (100%) in detecting B1 MβL-producing Enterobacterales. In disk potentiation test, the sensitivities using SFC and SPC were 89.1% and 93.8%, respectively, whereas the specificities for both were 100%. These methods are simple and inexpensive, and have a high accuracy rate. These methods would, therefore, be of immense assistance in the specific detection and discrimination of B1 MβL-producing Enterobacterales in clinical microbiology laboratories, and would lead to better prevention against infection with such multidrug-resistant bacteria in clinical settings.
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Evaluation of the Xpert Carba-R NxG Assay for Detection of Carbapenemase Genes in a Global Challenge Set of Pseudomonas aeruginosa Isolates. J Clin Microbiol 2020; 58:JCM.01098-20. [PMID: 33115845 DOI: 10.1128/jcm.01098-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 06/23/2020] [Indexed: 12/28/2022] Open
Abstract
The growing prevalence and diversity of carbapenemase producers among carbapenem-resistant Pseudomonas aeruginosa (CRPA) isolates warrants an expansion of detection capabilities. The purpose of this study was to evaluate the performance of the commercially available Xpert Carba-R (Carba-R) and the research-use-only Xpert Carba-R NxG (Carba-R NxG) in a global collection of P. aeruginosa The challenge set included 123 P. aeruginosa clinical isolates from 12 countries. Isolates were previously categorized via PCR or whole-genome sequencing. Carbapenemase classes tested include VIM, IMP, NDM, SPM, KPC, and GES. Non-carbapenemase (non-CP)-harboring isolates were also tested (negative control). Isolates were tested using the Carba-R NxG and the Carba-R tests per the manufacturer's instructions. Carba-R NxG testing was completed by Cepheid (Sunnyvale, CA), blinded to genotype. Both assays gave negative results for all non-CP isolates and positive results for all VIM, NDM, and KPC isolates. An improvement in IMP detection among isolates was observed (100% detection by Carba-R NxG versus 58% by Carba-R). All SPM and GES isolates, targets not present in commercially available Carba-R, were positive by Carba-R NxG. Two isolates harbored both VIM and GES, while a third isolate contained VIM and NDM. The Carba-R NxG identified both targets in all 3 isolates, while the Carba-R was negative for both GES-containing isolates. Overall, the Carba-R NxG successfully categorized 100% of isolates tested compared with 68% for its predecessor. The Carba-R NxG will expand the detection spectrum of the current Carba-R assay to include SPM, GES, and expanded IMP variants, increasing the global utility of the test.
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Lasko MJ, Gill CM, Asempa TE, Nicolau DP. EDTA-modified carbapenem inactivation method (eCIM) for detecting IMP Metallo-β-lactamase-producing Pseudomonas aeruginosa: an assessment of increasing EDTA concentrations. BMC Microbiol 2020; 20:220. [PMID: 32690021 PMCID: PMC7372831 DOI: 10.1186/s12866-020-01902-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/14/2020] [Indexed: 11/22/2022] Open
Abstract
Background Prompt identification of carbapenemase-harboring organisms is valuable in informing therapeutic and infection-control measures. The modified carbapenem inactivation method (mCIM) and EDTA-modified carbapenem inactivation method (eCIM) are inexpensive and easy to interpret phenotypic tests endorsed by the Clinical and Laboratory Standards Institute (CLSI) for the detection of carbapenemase-harboring Enterobacterales. Only mCIM is endorsed by CLSI for detecting carbapenemase-harboring Pseudomonas aeruginosa. eCIM’s ability to delineate serine and metallo-β-lactamases (MBL) could be advantageous in areas prevalent with carbapenemase-harboring P. aeruginosa. A recent assessment of mCIM/eCIM on MBL-harboring P. aeruginosa demonstrated high eCIM sensitivity for NDMs and VIMs but not for IMP-producers. Therefore, this study aimed to determine whether increasing EDTA concentrations would enhance eCIM sensitivity for a collection of IMP-harboring P. aeruginosa isolates. Twenty-six IMP-harboring P. aeruginosa isolates were utilized. For test validation, additional P. aeruginosa isolates harboring NDM (n = 3), VIM (n = 3), KPC (n = 8), wild-type (n = 1), and Enterobacterales isolates harboring IMP (n = 6) and NDM (n = 1) were assessed. The mCIM test was conducted as outlined by CLSI. Simultaneously, the eCIM test was performed with the standard 5 mM EDTA concentration and doubling EDTA concentrations: 10 mM, 20 mM, and 40 mM. Results Concentration-dependent improvement was observed among the IMP-harboring P. aeruginosa with eCIM sensitivities at 0, 31, 85, and 100% respectively. Remaining Enterobacterales and P. aeruginosa responded concordantly with their genotype at the standard 5 mM eCIM concentration, with doubling EDTA concentrations providing no greater sensitivity. Conclusion Combination of mCIM and an eCIM with a 40 mM EDTA concentration appropriately capture IMP-harboring P. aeruginosa without sacrificing test utility for other carbapenemase-harboring isolates.
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Affiliation(s)
- Maxwell J Lasko
- Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, CT, 06102, USA
| | - Christian M Gill
- Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, CT, 06102, USA
| | - Tomefa E Asempa
- Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, CT, 06102, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, CT, 06102, USA. .,Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA.
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Evaluation of the EDTA-Modified Carbapenem Inactivation Method for Detecting Metallo-β-Lactamase-Producing Pseudomonas aeruginosa. J Clin Microbiol 2020; 58:JCM.02015-19. [PMID: 32238433 DOI: 10.1128/jcm.02015-19] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 02/03/2020] [Indexed: 02/07/2023] Open
Abstract
The prevalence of carbapenem-resistant Pseudomonas aeruginosa is increasing. Identification of carbapenemase-producing P. aeruginosa will have therapeutic, epidemiological, and infection control implications. This study evaluated the performance of the EDTA-modified carbapenem inactivation method (eCIM) in tandem with the modified carbapenem inactivation method (mCIM) against a large collection of clinical P. aeruginosa isolates (n = 103) to provide clinicians a phenotypic test that not only identifies carbapenemase production but also distinguishes between metallo-β-lactamase and serine-carbapenemase production in P. aeruginosa The mCIM test was performed according to Clinical and Laboratory Standards Institute guidelines, while the eCIM was conducted as previously described for Enterobacteriaceae Test performance was compared to the genotypic profile as the reference. mCIM testing successfully categorized 91% (112/123) of P. aeruginosa isolates as carbapenemases or non-carbapenemase producers, with discordant isolates being primarily Guiana extended-spectrum (GES)-type producers. To increase the sensitivity of the mCIM for GES-harboring isolates, a double inoculum, prolonged incubation, or both was evaluated, with each modification improving sensitivity to 100% (12/12). Upon eCIM testing, all Verona integrin-encoded metallo-β-lactamases (VIM; n = 27) and New Delhi metallo-β-lactamases (NDM; n = 13) tested had 100% concordance to their genotypic profiles, whereas all Klebsiella pneumoniae carbapenemase (KPC; n = 8) and GES (n = 12) isolates tested negative, as expected, in the presence of EDTA. The eCIM failed to identify all imipenemase (IMP)-producing (n = 22) and Sao Paulo metallo-β-lactamase (SPM)-producing (n = 14) isolates. KPC-, VIM-, and NDM-producing P. aeruginosa were well defined by the conventional mCIM and eCIM testing methods; additional modifications appear required to differentiate GES-, IMP-, and SPM-producing isolates.
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Gutiérrez S, Correa A, Hernández-Gómez C, De La Cadena E, Pallares C, Villegas MV. Detection of carbapenemase-producing Pseudomonas aeruginosa: Evaluation of the carbapenem inactivation method (CIM). Enferm Infecc Microbiol Clin 2019; 37:648-651. [PMID: 30898368 DOI: 10.1016/j.eimc.2019.02.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 01/29/2019] [Accepted: 02/02/2019] [Indexed: 11/15/2022]
Abstract
INTRODUCTION The carbapenem inactivation method (CIM) is a cost-effective assay for detecting carbapenemases. However, its interpretation is unclear for Pseudomonas spp. We evaluate its accuracy when meropenem is changed to imipenem. METHODS We analyzed 266 P. aeruginosa isolates. The CIM method consists of: resuspend bacterial colonies (a full 10μL loop) in 400μL water, in which a 10μg disk of meropenem/imipenem is immersed. After 2h of incubation (35°C), remove the disk, place it onto a Mueller-Hinton agar plate previously inoculated with Escherichia coli (ATCC 25922), and incubate at 35 ̊C between 18-24 h. Interpretation criteria (mm of inhibition zone): ≤19mm, positive; ≥25mm negative; 20-24mm, undetermined. RESULTS Imipenem improves the sensitivity and specificity of CIM when compared to meropenem (99.4% and 98.9%, vs. 91.9% and 94.7%, respectively). CONCLUSIONS The accuracy of CIM for carbapenemase detection in P. aeruginosa is increased with the use of imipenem.
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Affiliation(s)
- Sergio Gutiérrez
- Bacterial Resistance and Hospital Epidemiology Unit, International Center for Medical Research and Training (CIDEIM), Cali, Colombia
| | - Adriana Correa
- Bacterial Resistance and Hospital Epidemiology Unit, International Center for Medical Research and Training (CIDEIM), Cali, Colombia; Universidad Santiago de Cali, Cali, Colombia
| | - Cristhian Hernández-Gómez
- Bacterial Resistance and Hospital Epidemiology Unit, International Center for Medical Research and Training (CIDEIM), Cali, Colombia; Grupo de Investigación en Resistencia Antimicrobiana y Epidemiología Hospitalaria - RAEH, Universidad El Bosque, Bogotá, Colombia
| | - Elsa De La Cadena
- Bacterial Resistance and Hospital Epidemiology Unit, International Center for Medical Research and Training (CIDEIM), Cali, Colombia; Grupo de Investigación en Resistencia Antimicrobiana y Epidemiología Hospitalaria - RAEH, Universidad El Bosque, Bogotá, Colombia
| | - Christian Pallares
- Bacterial Resistance and Hospital Epidemiology Unit, International Center for Medical Research and Training (CIDEIM), Cali, Colombia; Grupo de Investigación en Resistencia Antimicrobiana y Epidemiología Hospitalaria - RAEH, Universidad El Bosque, Bogotá, Colombia
| | - María Virginia Villegas
- Bacterial Resistance and Hospital Epidemiology Unit, International Center for Medical Research and Training (CIDEIM), Cali, Colombia; Grupo de Investigación en Resistencia Antimicrobiana y Epidemiología Hospitalaria - RAEH, Universidad El Bosque, Bogotá, Colombia.
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