Susceptibility of Elizabethkingia spp. to commonly tested and novel antibiotics and concordance between broth microdilution and automated testing methods

Abstract Objectives We aimed to determine susceptibilities of Elizabethkingia spp. to 25 commonly tested and 8 novel antibiotics, and to compare the performance of different susceptibility testing methods. Methods Clinical isolates of Elizabethkingia spp., Chryseobacterium spp. and Flavobacterium spp. collected during 2002–18 (n = 210) in a nationwide surveillance programme in Taiwan were speciated by 16S rRNA sequencing. MICs were determined by broth microdilution. The broth microdilution results of 18 common antibiotics were compared with those obtained by the VITEK 2 automated system. Results Among the Elizabethkingia spp. identified (n = 108), Elizabethkingia anophelis was the most prevalent (n = 90), followed by Elizabethkingia meningoseptica (n = 7) and Elizabethkingia miricola cluster [E. miricola (n = 6), Elizabethkingia bruuniana (n = 3) and Elizabethkingia ursingii (n = 2)]. Most isolates were recovered from respiratory or blood specimens from hospitalized, elderly patients. PFGE showed two major and several minor E. anophelis clones. All isolates were resistant to nearly all the tested β-lactams. Doxycycline, minocycline and trimethoprim/sulfamethoxazole inhibited >90% of Elizabethkingia spp. Rifampin inhibited E. meningoseptica (100%) and E. anophelis (81.1%). Fluoroquinolones and tigecycline were active against E. meningoseptica and E. miricola cluster isolates. Novel antibiotics, including imipenem/relebactam, meropenem/vaborbactam, ceftazidime/avibactam, cefepime/zidebactam, delafloxacin, eravacycline and omadacycline were ineffective but lascufloxacin inhibited half of Elizabethkingia spp. The very major discrepancy rates of VITEK 2 were >1.5% for ciprofloxacin, moxifloxacin and vancomycin. Major discrepancy rates were >3% for amikacin, tigecycline, piperacillin/tazobactam and trimethoprim/sulfamethoxazole. Conclusions MDR, absence of standard interpretation criteria and poor intermethod concordance necessitate working guidelines to facilitate future research of emerging Elizabethkingia spp.

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Colistin and Polymyxin B Susceptibility Testing for Carbapenem-Resistant and mcr -Positive Enterobacteriaceae: Comparison of Sensititre, MicroScan, Vitek 2, and Etest with Broth Microdilution

Journal of Clinical Microbiology ◽

10.1128/jcm.00268-17 ◽

2017 ◽

Vol 55 (9) ◽

pp. 2609-2616 ◽

Cited By ~ 78

Author(s):

Ka Lip Chew ◽

My-Van La ◽

Raymond T. P. Lin ◽

Jeanette W. P. Teo

Keyword(s):

Susceptibility Testing ◽

Polymyxin B ◽

Error Rates ◽

Test Results ◽

Broth Microdilution ◽

Major Error ◽

Testing Methods ◽

Content Type ◽

Carbapenem Resistant ◽

Vitek 2

ABSTRACT Colistin and polymyxin B remain part of the last line of antibiotics for multidrug-resistant Gram-negative bacteria, such as carbapenem-resistant Enterobacteriaceae . Current joint EUCAST-CLSI recommendations are for broth microdilution (BMD) to be performed for MIC testing of colistin. Commercial susceptibility testing methods were evaluated and compared against the reference BMD, using a susceptibility breakpoint of ≤2 mg/liter for both colistin and polymyxin B. Seventy-six Enterobacteriaceae were included, of which 21 were mcr-1 positive (18 Escherichia coli isolates, 2 Klebsiella pneumoniae isolates, and 1 Enterobacter aerogenes isolate). Rates of essential agreement (EA) of colistin test results between BMD and Vitek 2, Sensititre, and Etest were 93.4%, 89.5%, and 75.0%, respectively. Rates of EA of polymyxin B test results between BMD and Vitek 2, Sensititre, and Etest were 96.1%, 96.1%, and 48.7%, respectively. A positive MIC correlation with a categorical agreement of >90% was achieved for Sensititre (colistin Spearman's ρ = 0.863, and polymyxin B Spearman's ρ = 0.877) and Vitek 2 (polymyxin B [only] Spearman's ρ = 0.8917). Although a positive MIC correlation (Spearman's ρ = 0.873) with the reference method was achieved for colistin testing with Vitek 2, categorical agreement was <90%, with very major error rates of 36%. Correlation with the Etest MIC was lower, with very major error rates of 12% (colistin) and 26.1% (polymyxin B). MicroScan (colistin) categorical agreement was 88.2%, with a very major error rate of 4%. Colistin MICs for 15 of the 21 mcr-1 -positive isolates were >2 mg/liter, and polymyxin MICs for 17 of them were >2 mg/liter by broth microdilution. The use of a lower breakpoint of ≤1 mg/liter further improves detection of mcr-1 for all testing methods. However, further data on the correlation between MICs and clinical outcome are required to determine the most suitable breakpoint to guide clinical management.

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Comparative evaluation of broth microdilution with E-test, Vitek 2, and disk diffusion for susceptibility testing of colistin on Gram-negative bacteria

Indian Journal of Medical Sciences ◽

10.25259/ijms_15_2020 ◽

2021 ◽

Vol 73 ◽

pp. 93-98

Author(s):

Parul Gupta ◽

Rajni Sharma ◽

Aruna Vyas ◽

Amit Tak

Keyword(s):

Gold Standard ◽

Susceptibility Testing ◽

Multidrug Resistant ◽

Disk Diffusion ◽

Broth Microdilution ◽

Testing Methods ◽

Geometric Means ◽

Gram Negative ◽

Vitek 2 ◽

Good Concordance

Objectives: With the increasing threat of multidrug-resistant organisms, colistin has become popular in clinical practice. A better understanding of antimicrobial susceptibility testing methods for colistin is needed for optimal patient management. The aim of the study was to determine the accuracy of E-test, Vitek 2 system for the detection of colistin minimum inhibitory concentrations (MIC) against broth microdilution (BMD). Material and Methods: A total of 100 isolates of Gram-negative bacilli were subjected to susceptibility testing for colistin using the following methods: BMD, E-test, Vitek 2, and disk diffusion. Using BMD as the gold standard, comparative analysis between different methods was carried out. Results: Comparison of MIC values of E-test (GM = 0.488 mg/ml) against BMD (GM = 0.611 mg/ml using unpaired t-test (t = 2.015, P = 0.045) showed that geometric means of MIC values of E-strip were significantly lower than BMD. Similarly, comparison of MIC values of Vitek 2 system (GM = 0.615 mg/ml) against BMD (GM = 0.611 mg/ml) using unpaired t-test (t = −0.050, P = 0.960) showed no statistical significant differences in geometric means of MIC values. Taking reference as BMD method – the EA for E-strip is 57%, CA is 97%, VME is 2%, and no ME. Similarly, for the Vitek method EA is 64%, CA is 98%, VME is 1%, and ME is 1%. Conclusion: Different susceptibility testing methods for colistin show great variation in their results and BMD is the best candidate as gold standard. The Vitek 2 method showed good concordance with BMD.

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Comparative evaluation of susceptibility testing methods for colistin and polymyxin B among clinical isolates of carbapenem- resistant Klebsiella pneumoniae and Acinetobacter baumannii

The Journal of Infection in Developing Countries ◽

10.3855/jidc.9660 ◽

2018 ◽

Vol 12 (06) ◽

pp. 504-507 ◽

Cited By ~ 2

Author(s):

Yamuna Devi Bakthavatchalam ◽

Abirami Shankar ◽

Bhuvaneswari Thukaram ◽

Dhanabhagyam Naveena Krishnan ◽

Balaji Veeraraghavan

Keyword(s):

Comparative Evaluation ◽

Susceptibility Testing ◽

Reference Method ◽

Polymyxin B ◽

Disc Diffusion ◽

Broth Microdilution ◽

Testing Methods ◽

Carbapenem Resistant ◽

Clinical Laboratories ◽

Vitek 2

Susceptibility testing (ST) of colistin and polymyxin B is challenging. Disc diffusion testing is not reliable for polymyxin ST, because of poor diffusion. Currently, for polymyxin ST, the EUCAST-CLSI joint commission recommending broth microdilution (BMD) as the reference method. In this study, reliability of E-test and Vitek 2 was compared with BMD, using the susceptible breakpoint of ≤ 2μg/ml for both colistin and polymyxin B. Overall, essential agreement (EA) for colistin between E-test, Vitek2 and BMD were 37% and 74% respectively. EA for polymyxin B between E-test and BMD were 65%. Very major error (VME) for colistin and polymyxin B with E-test were 42% and 55% respectively. An unacceptable VME of 11% was seen for colistin with Vitek2. Major errors (MEs) were rather limited with both E-test and Vitek2. E-test and Vitek2 may lead to inappropriate decision-making for colistin/polymyxin B therapy. Thus, clinical laboratories should consider BMD for polymyxin ST.

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A Review on Automatic Bill of Material Generation and Visual Inspection on PCBs

ISTFA 2019: Conference Proceedings from the 45th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2019p0256 ◽

2019 ◽

Author(s):

Mukhil Azhagan M. S ◽

Dhwani Mehta ◽

Hangwei Lu ◽

Sudarshan Agrawal ◽

Mark Tehranipoor ◽

...

Keyword(s):

Image Analysis ◽

Visual Inspection ◽

Automated System ◽

Imaging Modalities ◽

Future Research ◽

Analysis Techniques ◽

Bill Of Materials ◽

Pros And Cons ◽

Index Terms ◽

Image Analysis Techniques

Abstract Globalization and complexity of the PCB supply chain has made hardware assurance a challenging task. An automated system to extract the Bill of Materials (BoM) can save time and resources during the authentication process, however, there are numerous imaging modalities and image analysis techniques that can be used to create such a system. In this paper we review different imaging modalities and their pros and cons for automatic PCB inspection. In addition, image analysis techniques commonly used for such images are reviewed in a systematic way to provide a direction for future research in this area. Index Terms—Component Detection, PCB, Authentication, Image Analysis, Machine Learning

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Association Between Federal Value-Based Incentive Program Implementation and Hospital-Onset C. difficile Infection Rates

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2020.645 ◽

2020 ◽

Vol 41 (S1) ◽

pp. s133-s133

Author(s):

Mohammad Alrawashdeh ◽

Chanu Rhee ◽

Heather Hsu ◽

Grace Lee

Keyword(s):

Program Implementation ◽

Negative Binomial ◽

Negative Binomial Regression ◽

Neutralization Assay ◽

Nucleic Acid Amplification ◽

Teaching Hospitals ◽

Future Research ◽

Testing Methods ◽

Toxigenic Culture ◽

The Impact

Background: The Hospital-Acquired Conditions Reduction Program (HACRP) and Hospital Value-Based Purchasing (HVBP) are federal value-based incentive programs that financially reward or penalize hospitals based on quality metrics. Hospital-onset C. difficile infection (HO-CDI) rates reported to the CDC NHSN became a target quality metric for both HACRP and HVBP in October 2016, but the impact of these programs on HO-CDI rates is unknown. Methods: We used an interrupted time-series design to examine the association between HACRP/HVBP implementation in October 2016 and quarterly rates of HO-CDI per 10,000 patient days among incentive-eligible acute-care hospitals conducting facility-wide HO-CDI NHSN surveillance between January 2013 and March 2019. Generalized estimating equations were used to fit negative binomial regression models to assess for immediate program impact (ie, level change) and changes in the slope of HO-CDI rates, controlling for each hospital’s predominant method for CDI testing (nucleic acid amplification including PCR (NAAT), enzyme immunoassay for toxin (EIA), or other testing method including cell cytotoxicity neutralization assay and toxigenic culture). Results: Of the 265 study hospitals studied, most were medium-sized (100–399 beds, 55%), not-for-profit (77%), teaching hospitals (70%), and were located in a metropolitan area (87%). Compared to EIA, rates of HO-CDI were higher when detected by NAAT (incidence rate ratio [IRR], 1.55; 95% CI, 1.41–1.70) or other testing methods (IRR, 1.47; 95% CI, 1.26–1.71). Controlling for CDI testing methods, HACRP/HVBP implementation was associated with an immediate 6% decline in HO-CDI rates (IRR, 0.94; 95% CI, 0.89–0.99) and a 4% decline in slope per year-quarter thereafter (IRR, 0.96; 95% CI, 0.95–0.97) (Fig. 1). Conclusions: HACRP/HVBP implementation was associated with both immediate and gradual improvements in HO-CDI rates, independent of CDI testing methods of differing sensitivity. Future research may evaluate the precise mechanisms underlying this improvement and if this impact is sustained in the long term.Funding: NoneDisclosures: None

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Comparison of Polymyxin B, Tigecycline, Cefepime, and Meropenem MICs for KPC-Producing Klebsiella pneumoniae by Broth Microdilution, Vitek 2, and Etest

Journal of Clinical Microbiology ◽

10.1128/jcm.00760-13 ◽

2013 ◽

Vol 51 (7) ◽

pp. 2472-2472

Author(s):

A. Lat ◽

S. A. Clock ◽

F. Wu ◽

S. Whittier ◽

P. Della-Latta ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Polymyxin B ◽

Broth Microdilution ◽

Vitek 2

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Multicenter clinical evaluation of VITEK® 2 meropenem-vaborbactam for susceptibility testing of Enterobacterales and Pseudomonas aeruginosa

Journal of Clinical Microbiology ◽

10.1128/jcm.01610-21 ◽

2021 ◽

Author(s):

Hari P. Dwivedi ◽

Simone Franklin ◽

Sukantha Chandrasekaran ◽

Omai Garner ◽

Maria M. Traczewski ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Susceptibility Testing ◽

Automated System ◽

Individual Species ◽

Method Performance ◽

Overall Performance ◽

Vitek 2 ◽

Tract Infections ◽

Alternate Solution ◽

After Error

The carbapenem/beta-lactamase inhibitor (meropenem-vaborbactam; MEV) used to treat complicated urinary tract infections and pyelonephritis in adults was approved in 2017 by the U.S. Food and Drug Administration (FDA). We evaluated VITEK 2 MEV (bioMérieux, Durham, NC) compared to the reference broth microdilution (BMD) method. Of 449 Enterobacterales isolates analyzed per FDA/CLSI breakpoints, overall performance was 98.2% Essential Agreement (EA), 98.7% Category Agreement (CA), and 0% Very Major Errors (VME) or Major Errors (ME). For FDA intended for use 438 Enterobacterales isolates, performance was 98.2% EA, 98.6% CA, and 0% VME or ME. Evaluable EA was 81.0% but with only 42 on-scale evaluable results. Individual species demonstrated EA and CA rates ≥ 90% without any VME or ME. When evaluated using European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints, overall VITEK 2 MEV performance for Enterobacterales and Pseudomonas aeruginosa demonstrated 97.3% EA, 99.2% CA, 2.3% VME, and 0.6% ME (after error resolution: 97.3% EA, 99.4% CA, 2.2% VME, and 0.4% ME) compared to the reference BMD method. Performance for P. aeruginosa included 92.2% EA, 97.4% CA, 0% VME, and 3.0% ME (after error resolution: 92.2% EA, 98.7% CA, 0% VME, and 1.5% ME). Performance for Enterobacterales included 98.2% EA, 99.6% CA, 3.0% VME, and 0.2% ME. Evaluable EA was 80.6% but due to only 67 evaluable results. These findings support VITEK 2 MEV as an accurate automated system for MEV susceptibility testing of Enterobacterales and P. aeruginosa and could be an alternate solution to the manual labor intensive reference BMD method.

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Distribution of MR-CoNS in the clinical staffs of tertiary care hospital

IP International Journal of Medical Microbiology and Tropical Diseases ◽

10.18231/j.ijmmtd.2021.022 ◽

2021 ◽

Vol 7 (2) ◽

pp. 100-102

Author(s):

Sonu S. Ahirwar ◽

Prabhat Jatav ◽

Kirti Kushwaha

Keyword(s):

Low Income ◽

Nasal Swab ◽

Tertiary Care Hospital ◽

Methicillin Resistance ◽

Tertiary Care ◽

Automated System ◽

Diffusion Method ◽

Care Hospital ◽

Methicillin Resistant ◽

Vitek 2

Methicillin-resistant coagulase-negative staphylococci (MR-CoNS) associated infection is a growing concern in healthcare settings now a day. MR-CoNS are the main infectious agents of the hospital acquired infection. Clinical staffs to patients transmission of resistant strains have caused a rapid increase in the prevalence of antimicrobial resistance in recent years. Growing rate of antimicrobial resistant against available antibiotics of MR-CoNS is a developing problem in low income or lower middle income counties. This study was conducted to determine the occurrence MR-CoNS isolated from different clinical staffs of tertiary care hospital. This prospective study conducted in clinical staffs, nasal swab were collected from all the participants. Screening of CoNS were done on the basis of cultural, morphological and biochemical tests, identification and AST analysis done by VITEK-2 automated system. Methicillin resistance pattern was checked by VITEK-2 and Kirby-Bauer disc diffusion method according to CLSI guideline. A total of 129 nasal swab samples were collected from clinical staffs, of which n=81 isolates (85.6%) were CoNS. Among n=81 CoNS, (48.12%) , (41.97%) , (7.4%) and (2.4%) were reported. Out of n=81 CoNS isolates, n=26 were conformed as MR-CoNS. Maximum methicillin resistance were reported in 53.48% (14/26), 42.30% (11/26), 3.84% (1/26) and 0% (0/26). Theoccurrence rate of MR-CoNS are higher (20.6%) in the healthcare workers and most of the methicillin resistant-CoNS isolates shows high level of resistance against widely used antibiotics but all the isolates susceptible against vancomycin.

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