Performance of Vitek 2 in Antimicrobial Susceptibility Testing of
            <i>Pseudomonas aeruginosa</i>
            Isolates with Different Mechanisms of β-Lactam Resistance

Mazzariol, Annarita; Aldegheri, Marco; Ligozzi, Marco; Cascio, Giuliana Lo; Koncan, Raffaella; Fontana, Roberta

doi:10.1128/jcm.02216-07

Cited by 20 publications

(7 citation statements)

References 17 publications

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“…Due to this problem, laboratories might consider primary testing of mucoid isolates by disk diffusion. The most notable errors occurred in P. aeruginosa isolates with piperacillin-tazobactam, as has been seen by others (5,7,11,12). Unlike these previous studies that found piperacillin-tazobactam VME rates ranging from 10.2 to 21.7% (5, 7, 10), we found 0 VMEs and only 3 (4.3%) MEs.…”

Section: Discussioncontrasting

confidence: 55%

Performance of Vitek 2 for Antimicrobial Susceptibility Testing of Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia with Vitek 2 (2009 FDA) and CLSI M100S 26th Edition Breakpoints

et al. 2017

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The performances of Vitek 2 AST-GN69 and AST-XN06 cards were compared to Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution (BMD) for 99 isolates of Pseudomonas aeruginosa, 26 Acinetobacter baumannii isolates, and 11 Stenotrophomonas maltophilia isolates. In total, 15 antimicrobials were evaluated, with 11 for P. aeruginosa, 14 for A. baumannii, and 2 for S. maltophilia. Categorical agreement (CA) was assessed using both Vitek 2 breakpoints and 2016 CLSI M100S 26th edition breakpoints. The essential agreement values for P. aeruginosa, A. baumannii, and S. maltophilia were 99.5%, 99.2%, and 100%, respectively. The CA values for P. aeruginosa, A. baumannii, and S. maltophilia were 94.1%, 92.7%, and 95.5%, respectively, by the Vitek 2 breakpoints, and 93.4%, 92.3%, and 95.5%, respectively, by the CLSI breakpoints. Overall, the Vitek 2 performance was comparable to that of BMD using both Vitek 2 breakpoints and 2016 CLSI M100S 26th edition breakpoints. Improved performance was noted for the reformulated piperacillin-tazobactam and imipenem found on the AST-GN69 card, with no very major or major errors noted when using the CLSI breakpoints.KEYWORDS Acinetobacter baumannii, antimicrobial susceptibility testing, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Vitek 2, breakpoints, broth microdilution M ultidrug resistance (MDR) among Gram-negative bacteria, which is defined by nonsusceptibility (intermediate or resistant) to Ն1 agent in Ն3 antimicrobial categories (1), is a significant clinical concern. In the United States, 12.6% of health care-associated infections (HAIs) caused by Pseudomonas aeruginosa are due to MDR isolates, as are 45.3% of Acinetobacter species (2). Infections caused by these MDR organisms are associated with poor clinical outcomes, particularly for patients who are immunocompromised, have prolonged hospitalization in the intensive care unit, or who reside in long-term-care facilities (3). The treatment options for MDR infections are limited, making accurate and timely antimicrobial susceptibility testing (AST) critical for patient care.Most U.S. clinical laboratories use commercial automated systems for AST, including the bioMérieux Vitek 2. However, the failure of these systems to detect resistance in Gram-negative bacteria, and in particular ␤-lactam resistance in nonfermenting Gramnegative bacilli, such as P. aeruginosa and Acinetobacter baumannii, has been reported by several studies (4-7). In 2010, bioMérieux issued a voluntary recall of AST cards

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Section: Discussioncontrasting

confidence: 55%

Performance of Vitek 2 for Antimicrobial Susceptibility Testing of Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia with Vitek 2 (2009 FDA) and CLSI M100S 26th Edition Breakpoints

et al. 2017

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“…14,15,17 Concerns regarding the reliability of automated susceptibility testing have been previously described for P. aeruginosa. 22,23 In the current study, disk diffusion was exclusively used for all P. aeruginosa susceptibility testing.…”

Section: Discussionmentioning

confidence: 99%

Results of a local combination therapy antibiogram for Pseudomonas aeruginosa isolates: is double worth the trouble?

Song

Dilworth

Munson

et al. 2017

Therapeutic Advances in Infection

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Purpose: To determine the frequency at which fluoroquinolones and aminoglycosides demonstrate in vitro activity against non-urinary, non-skin/skin structure Pseudomonas aeruginosa isolates exhibiting decreased susceptibilities to one or more β-lactam agents. Methods: β-lactam-non-susceptible P. aeruginosa isolates recovered from blood, bone, lower respiratory tract, pleural fluid, cerebrospinal fluid, or peritoneal fluid cultures between October 2010 and October 2014 were reviewed from four community hospitals within a single health-system. Only the first isolate per patient was included for analysis. The likelihood that each isolate was susceptible to a non-β-lactam antimicrobial was then determined and summarized within a combination antibiogram. Results: In total, 179 P. aeruginosa isolates with decreased susceptibilities to one or more β-lactam agents were assessed. Because no appreciable differences in antimicrobial susceptibility profile were observed between hospitals, the isolates were evaluated in aggregate. Susceptibility rates for β-lactam monotherapy ranged from 34% to 75%. Aminoglycosides possessed increased antibacterial activity compared to fluoroquinolones. Tobramycin was the non-β-lactam most likely to expand antimicrobial coverage against β-lactam-non-susceptible P. aeruginosa with activity against 64%, 66%, and 65% of cefepime-, piperacillin-tazobactam-, and meropenem-non-susceptible isolates, respectively (p < 0.001 for all). Conclusions:The results of this study support the use of aminoglycosides over fluoroquinolones for achieving optimal, empiric antimicrobial combination therapy for P. aeruginosa when dual antimicrobial therapy is clinically necessary. Future efforts aimed at optimizing combination therapy for P. aeruginosa should focus on systemic interventions that limit the selection of fluoroquinolones in combination with β-lactams to expand coverage based on local susceptibility rates.

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“…Minor errors were found in 5.1% of strains, and major and very major errors were found in 1.6% and 0.3% of strains, respectively in the same study. 21 Annarita Mazzariol et al 22 demonstrated that VITEK 2 could be used with confidence for identifying resistance to several antimicrobial agents against P. aeruginosa including imipenem.…”

Section: Discussionmentioning

confidence: 99%

Comparison of Meropenem MIC by E Test and VITEK 2 in Resistant Pseudomonas and Acinetobacter Isolates

Kottahachchi

Faoagali²,

Kleinschmidt³

2012

Sri Lankan J Infec Dis

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Pseudomonas aeruginosa and Acinetobacter baumannii cause serious infections in health care institutions. Many isolates are multidrug resistant and sometimes resistant even to meropenem. The minimum inhibitory concentration (MIC) of an antibiotic is useful to decide on specific treatment and several methods of detecting MIC are in current use. Routine application of such methods is cumbersome for clinical laboratories and the newly introduced VITEK 2 automated method is an attractive alternative. The aims of the study were to compare the performance of the E test and the VITEK 2 system in susceptibility testing of resistant strains of P.aeruginosa and A. baumannii to meropenem and to compare the MIC of four different carbapenem antibiotics for P.aeruginosa and A.baumannii. 75 strains of P.aeruginosa and 25 of A.baumanii were selected randomly from the isolate collection of the Princess Alexandra Hospital, Australia. MIC testing using the E test and the VITEK 2 MIC were performed for each isolate according to the manufacturer's instructions and the CLSI guidelines of June, 2010. MICs obtained by VITEK-2 corresponded closely with those obtained with the E test method. Categorical agreement testing for both organisms was 92% with no major errors and 08% minor errors. We conclude that VITEK 2 is a reliable method to determine MIC to meropenem for P. aeruginosa and A. baumanii. Doripenem sensitivity results can be extrapolated from the meropenem sensitivity results. 29

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Performance of Vitek 2 in Antimicrobial Susceptibility Testing of Pseudomonas aeruginosa Isolates with Different Mechanisms of β-Lactam Resistance

Cited by 20 publications

References 17 publications

Performance of Vitek 2 for Antimicrobial Susceptibility Testing of Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia with Vitek 2 (2009 FDA) and CLSI M100S 26th Edition Breakpoints

Performance of Vitek 2 for Antimicrobial Susceptibility Testing of Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia with Vitek 2 (2009 FDA) and CLSI M100S 26th Edition Breakpoints

Results of a local combination therapy antibiogram for Pseudomonas aeruginosa isolates: is double worth the trouble?

Comparison of Meropenem MIC by E Test and VITEK 2 in Resistant Pseudomonas and Acinetobacter Isolates

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