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Rice KS, Luethy PM. Overprediction of Carbapenemase-Containing Isolates by an Automated AST Instrument's Computer Algorithm. J Appl Lab Med 2022; 7:1283-1289. [PMID: 36214370 DOI: 10.1093/jalm/jfac077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 08/02/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND The VITEK® 2 is generally accepted as a reliable method for predicting antibiotic resistance mechanisms including aminoglycoside phenotypes, beta lactam phenotypes, impermeability, and penicillinases. However, when it comes to predicting carbapenemases, the research that has been done is inconsistent in both methods and results. METHODS We compared the predictions of the VITEK 2 and Advanced Expert System™ (AES) with the results of the modified carbapenemase inactivation method in an academic medical center lab to evaluate the clinical reliability of the VITEK 2 and AES in routine workflow for the detection of carbapenemases. RESULTS Our findings show that the positive predictive value of carbapenemase detection on the VITEK2 and AES is 30.3% (91/300) in our patient population. CONCLUSIONS In light of these results, we propose that the VITEK 2 and AES be used as a screening tool for carbapenemase-containing organisms rather than as a definitive test.
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Affiliation(s)
- Kathryn S Rice
- Department of Pathology, University of Maryland Medical System, Baltimore, MD 21201, USA
| | - Paul M Luethy
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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2
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Adelman MW, Bower CW, Grass JE, Ansari UA, Soda EA, See I, Lutgring JD, Jacob JT. Distinctive Features of Ertapenem-Mono-Resistant Carbapenem-Resistant Enterobacterales in the United States: A Cohort Study. Open Forum Infect Dis 2022; 9:ofab643. [PMID: 35036469 PMCID: PMC8754373 DOI: 10.1093/ofid/ofab643] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 12/28/2021] [Indexed: 11/26/2022] Open
Abstract
Background Carbapenem-resistant Enterobacterales (CRE) are highly antibiotic-resistant bacteria. Whether CRE resistant only to ertapenem among carbapenems (ertapenem “mono-resistant”) represent a unique CRE subset with regards to risk factors, carbapenemase genes, and outcomes is unknown. Methods We analyzed surveillance data from 9 CDC Emerging Infections Program (EIP) sites. A case was the first isolation of a carbapenem-resistant Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, K. oxytoca, K. pneumoniae, or K. variicola from a normally sterile site or urine in an EIP catchment area resident in 2016–2017. We compared risk factors, carbapenemase genes, antibiotic susceptibility, and mortality of ertapenem “mono-resistant” cases to “other” CRE cases (resistant to ≥1 carbapenem other than ertapenem) and analyzed risk factors for mortality. Results Of 2009 cases, 1249 (62.2%) were ertapenem-mono-resistant and 760 (37.8%) were other CRE. Ertapenem-mono-resistant CRE cases were more frequently ≥80 years old (29.1% vs 19.5%; P < .0001) and female (67.9% vs 59.0%; P < .0001). Ertapenem-mono-resistant isolates were more likely to be Enterobacter cloacae complex (48.4% vs 15.4%; P < .0001) but less likely to be isolated from a normally sterile site (7.1% vs 11.7%; P < .01) or to have a carbapenemase gene (2.4% vs 47.4%; P < .0001). Ertapenem-mono-resistance was not associated with 90-day mortality in logistic regression models. Carbapenemase-positive isolates were associated with mortality (odds ratio, 1.93; 95% CI, 1.30–2.86). Conclusions Ertapenem-mono-resistant CRE rarely have carbapenemase genes and have distinct clinical and microbiologic characteristics from other CRE. These findings may inform antibiotic choice and infection prevention practices, particularly when carbapenemase testing is not available.
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Affiliation(s)
- Max W Adelman
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA.,Georgia Emerging Infections Program, Decatur, Georgia, USA
| | - Chris W Bower
- Georgia Emerging Infections Program, Decatur, Georgia, USA.,Atlanta VA Medical Center, Decatur, Georgia, USA.,Foundation for Atlanta Veterans Education and Research, Decatur, Georgia, USA
| | - Julian E Grass
- Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Uzma A Ansari
- Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Elizabeth A Soda
- Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Isaac See
- Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Joseph D Lutgring
- Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Jesse T Jacob
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA.,Georgia Emerging Infections Program, Decatur, Georgia, USA.,Department of Epidemiology, Emory University Rollins School of Public Health, Atlanta, Georgia, USA.,Emory Antibiotic Research Center, Emory University School of Medicine, Atlanta, Georgia, USA
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Hickey C, Nguyen S, Anes J, Hurley D, Donoghue O, Fanning S, Schaffer K. Differences in antimicrobial susceptibility testing complicating management of IMP carbapenemase-producing Enterobacterales infection. J Glob Antimicrob Resist 2021; 27:284-288. [PMID: 34775131 DOI: 10.1016/j.jgar.2021.09.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 09/02/2021] [Accepted: 09/29/2021] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVES IMP-type carbapenemases are rarely detected in Europe and limited information is available to guide the treatment of infections caused by carbapenemase-producing Enterobacterales (CPE) producing these carbapenemases. Accurate antimicrobial susceptibility testing (AST) results are essential for optimal antibiotic management. Here we report discrepancies in AST of IMP-producing Enterobacterales (IMP-CPE) complicating the management of severe sepsis. METHODS Antimicrobial susceptibilities were analysed by in-house VITEK® 2, Etest and broth microdilution (BMD). Carbapenemase-encoding genes were detected by PCR. Whole-genome sequencing (WGS) was performed using an Illumina MiSeq platform. RESULTS Minimum inhibitory concentrations (MICs) determined by VITEK® 2 for Enterobacter hormaechei and Klebsiella oxytoca blood culture isolates were ≥16 mg/L for meropenem and ≤0.5 mg/L for ertapenem. In contrast, Etest analysis and BMD returned MICs of 2 mg/L and 1 mg/L, respectively. Both isolates tested positive for IMP carbapenemase-encoding genes by PCR. WGS revealed that both isolates carried the same blaIMP-4 gene. Based on VITEK® 2 susceptibilities, initial treatment was with tigecycline and amikacin. After subsequent deterioration, the patient was successfully treated with ertapenem and amikacin. CONCLUSION This case highlights that automated AST by VITEK® 2 can over-report meropenem resistance for IMP carbapenemase-producers compared with Etest and BMD. Clinicians need to be cautious deciding against carbapenem treatment based on VITEK® 2 susceptibility testing results for IMP-positive Enterobacterales. Tigecycline was inferior to carbapenem treatment for pyelonephritis caused by isolates expressing IMP carbapenemases, however specific evidence guiding the treatment of these infections is lacking.
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Affiliation(s)
- C Hickey
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Department of Clinical Microbiology, St Vincent's University Hospital, Elm Park, Dublin D04 T6F4, Ireland
| | - S Nguyen
- School of Public Health, Physiotherapy & Sports Science, University College Dublin, Belfield, Dublin D04 N2E5, Ireland
| | - J Anes
- School of Public Health, Physiotherapy & Sports Science, University College Dublin, Belfield, Dublin D04 N2E5, Ireland
| | - D Hurley
- School of Public Health, Physiotherapy & Sports Science, University College Dublin, Belfield, Dublin D04 N2E5, Ireland
| | - O Donoghue
- Department of Clinical Microbiology, St Vincent's University Hospital, Elm Park, Dublin D04 T6F4, Ireland
| | - S Fanning
- School of Public Health, Physiotherapy & Sports Science, University College Dublin, Belfield, Dublin D04 N2E5, Ireland
| | - K Schaffer
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Department of Clinical Microbiology, St Vincent's University Hospital, Elm Park, Dublin D04 T6F4, Ireland.
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Bialvaei AZ, Kafil HS, Asgharzadeh M, Yousef Memar M, Yousefi M. Current methods for the identification of carbapenemases. J Chemother 2017; 28:1-19. [PMID: 26256147 DOI: 10.1179/1973947815y.0000000063] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Detection of carbapenemases in clinical microbiology labs is a challenging issue. Comparison of the results of susceptibility testing with the breakpoint values of carbapenems is the first step in the screening of carbapenemase producers. To date, screening of carbapenemase-producing (CP) bacteria has been mostly performed by a selective medium. Although these media are practical for the detection of most CP isolates, the inoculated plates have to be incubated overnight. Subsequently, we need the confirmation of the carbapenemase producers present in the culture medium by additional testing [e.g. inhibition studies with liquid or solid media, modified Hodge test (MHT), or gradient strips], which can take up to another 48 hours. Despite the lack of discrimination between the three different classes of carbapenemases (KPC, MBL and OXA) and difficulties in the interpretation of the results, the MHT is usually deemed as the phenotypic reference method for the confirmation of carbapenemase production. Molecular techniques, such as real-time polymerase chain reaction (PCR) assays, in contrast to phenotypic methods that are very time consuming, are faster and allow for the quick identification of carbapenemase genes. These techniques can detect and characterize carbapenemases, including NDM- and KPC-mediated resistance, which is critical for epidemiological investigations. The aim of this review is to gather a summary of the available methods for carbapenemase detection and describe the strengths and weaknesses of each method.
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Affiliation(s)
- Abed Zahedi Bialvaei
- a Drug Applied Research Center, Faculty of Medical Sciences , Tabriz University of Medical Sciences , Iran
| | - Hossein Samadi Kafil
- a Drug Applied Research Center, Faculty of Medical Sciences , Tabriz University of Medical Sciences , Iran
| | | | - Mohammad Yousef Memar
- c Infectious Disease and Tropical Medicine Research Center , Tabriz University of Medical Sciences , Iran
| | - Mehdi Yousefi
- d Immunology Research Center , Tabriz University of Medical Sciences , Iran
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Jean SS, Liao CH, Sheng WH, Lee WS, Hsueh PR. Comparison of commonly used antimicrobial susceptibility testing methods for evaluating susceptibilities of clinical isolates of Enterobacteriaceae and nonfermentative Gram-negative bacilli to cefoperazone-sulbactam. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2015; 50:454-463. [PMID: 26454423 DOI: 10.1016/j.jmii.2015.08.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 08/25/2015] [Accepted: 08/29/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND/PURPOSE The aim of this study was to investigate the cefoperazone-sulbactam (CFP-SUL) susceptibilities of important Gram-negative bacteria (GNB) by agar dilution (reference method), disk diffusion, and two automated methods. METHODS A total of 799 GNB isolates, including Enterobacteriaceae (n = 500) and nonfermentative GNB (NFGNB, n = 299), were recovered from various clinical specimens collected at National Taiwan University Hospital, Taipei, Taiwan from November 2013 to December 2014. The agar dilution method, disk diffusion method, and two automated susceptibility systems (Phoenix and Vitek 2) were used for testing susceptibility of the isolates to CFP-SUL. Categories of susceptibility (susceptible, intermediate, or resistant) to CFP-SUL yielded from each method were interpreted according to CFP-SUL interpretive breakpoints proposed previously. The results of categorical agreement and errors obtained between the agar dilution method and the other three methods were analyzed. RESULTS The Vitek 2 system had the highest error rates against Escherichia coli (n = 150) and Enterobacter cloacae (n = 77) isolates, i.e., 6.7% and 11.7% minor errors, 8.5% and 1.7% major errors, and 40% and 20% very major errors, respectively. Additionally, the Vitek 2 system was also found to have a significantly lower sensitivity (44.4%) and lower positive predictive value (18.2%) for detecting CFP-SUL nonsusceptible E. coli isolates than other methods. For carbapenem-nonsusceptible Enterobacteriaceae isolates, the Vitek 2 system failed to detect correct susceptibility to CFP-SUL. The three methods failed to correctly detect CFP-SUL susceptibility categories against all NFGNB isolates except Pseudomonas aeruginosa. CONCLUSION The Vitek 2 system is a suboptimal method in correctly detecting CFP-SUL susceptibility categories for E. coli, E. cloacae, and carbapenem-nonsusceptible Enterobacteriaceae isolates.
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Affiliation(s)
- Shio-Shin Jean
- Emergency Department, Department of Emergency and Critical Care Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Chun-Hsing Liao
- Department of Internal Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Wang-Huei Sheng
- Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Wen-Sen Lee
- Division of Infectious Diseases, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Po-Ren Hsueh
- Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan.
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Pailhoriès H, Lemarié C, Kempf M, Mahaza C, Joly-Guillou ML, Eveillard M. Retrospective detection of the hidden spread of OXA-48-producing Klebsiella pneumoniae in a French teaching hospital. J Infect 2015; 71:407-9. [DOI: 10.1016/j.jinf.2015.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 05/09/2015] [Indexed: 11/16/2022]
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Lee M, Chung HS. Different antimicrobial susceptibility testing methods to detect ertapenem resistance in Enterobacteriaceae: VITEK2, MicroScan, Etest, disk diffusion, and broth microdilution. J Microbiol Methods 2015; 112:87-91. [PMID: 25794901 DOI: 10.1016/j.mimet.2015.03.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 03/16/2015] [Accepted: 03/16/2015] [Indexed: 11/17/2022]
Abstract
We investigated different antimicrobial susceptibility testing methods to detect ertapenem resistance in Enterobacteriaceae. A total of 72 Enterobacteriaceae isolates were collected from a clinical microbiology laboratory of a tertiary university hospital, all of which were detected ertapenem resistance by the VITEK2 system. Bacterial identification and antimicrobial susceptibility were determined using the VITEK2. Ertapenem susceptibility test was performed using the MicroScan, Etest and a disk diffusion test. Ertapenem MICs were confirmed using the broth microdilution (BMD). Sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) of each method for the detection of ertapenem resistance were calculated. Carbapenemases and AmpC β-lactamase were screened using phenotypic methods. Among the 72 isolates, 20 isolates (27.8%) were resistant to ertapenem. Etest showed high sensitivity and specificity (85.0% and 88.5%, respectively) and excellent concordance with BMD. The disk diffusion test had the lowest sensitivity of 50.0%. The VITEK2 showed the lowest essential and categorical agreement (30.5% and 27.8%, respectively). The MicroScan showed relatively good agreement with BMD compared to the VITEK2. Most category disagreements were minor errors. There were 3 very major errors in both the MicroScan and disk diffusion test. Only 1 isolate was positive for carbapenemase screening test and all of the isolates were positive for AmpC screening test. In conclusion, the detection of ertapenem resistance in Enterobacteriaceae has limitations using routine testing such as an automated system or disk diffusion. Confirmation of results by an additional MIC test is recommended for accurate resistance results of ertapenem.
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Affiliation(s)
- Miae Lee
- Department of Laboratory Medicine, Ewha Womans University School of Medicine, Republic of Korea
| | - Hae-Sun Chung
- Department of Laboratory Medicine, Ewha Womans University School of Medicine, Republic of Korea.
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Performance of Vitek 2 for antimicrobial susceptibility testing of Enterobacteriaceae with Vitek 2 (2009 FDA) and 2014 CLSI breakpoints. J Clin Microbiol 2014; 53:816-23. [PMID: 25540403 DOI: 10.1128/jcm.02697-14] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vitek 2 (bioMérieux Inc., Durham, NC) is a widely used commercial antimicrobial susceptibility test system. We compared the MIC results obtained using the Vitek 2 AST-GN69 and AST-XN06 cards to those obtained by CLSI broth microdilution (BMD) for 255 isolates of Enterobacteriaceae, including 25 isolates of carbapenem-resistant Enterobacteriaceae. In total, 25 antimicrobial agents were examined. For 10 agents, the MIC data were evaluated using two sets of breakpoints: (i) the Vitek 2 breakpoints, which utilized the 2009 FDA breakpoints at the time of the study and are equivalent to the 2009 CLSI M100-S19 breakpoints, and (ii) the 2014 CLSI M100-S24 breakpoints. There was an overall 98.7% essential agreement (EA). The categorical agreement was 95.5% (CA) using the Vitek 2 breakpoints and 95.7% using the CLSI breakpoints. There was 1 very major error (VME) (0.05%) observed using the Vitek 2 breakpoints (cefazolin) and 8 VMEs (0.5%) using the CLSI breakpoints (2 each for aztreonam, cefepime, and ceftriaxone, and 1 for cefazolin and ceftazidime). Fifteen major errors (MEs) (0.4%) were noted using the Vitek 2 breakpoints and 8 (0.5%) using the CLSI breakpoints. Overall, the Vitek 2 performance was comparable to that of BMD for testing a limited number of Enterobacteriaceae commonly isolated by clinical laboratories. Ongoing studies are warranted to assess performance in isolates with emerging resistance.
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