scholarly journals Comparison of Phenotypic Tests and an Immunochromatographic Assay and Development of a New Algorithm for Detection of OXA-48-like Carbapenemases

2016 ◽  
Vol 55 (3) ◽  
pp. 877-883 ◽  
Author(s):  
Florian Koroska ◽  
Stephan Göttig ◽  
Martin Kaase ◽  
Jörg Steinmann ◽  
Sören Gatermann ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Gold Standard ◽  
Molecular Detection ◽  
Specific Inhibitor ◽  
Cost Effective ◽  
Immunochromatographic Assay ◽  
Content Type ◽  
Class A ◽  
Phenotypic Tests ◽  
Disk Test

ABSTRACT OXA-48 is the most prevalent carbapenemase in Enterobacteriaceae in Europe and the Middle East, but it is frequently missed because many isolates display low MICs for carbapenems. Furthermore, in contrast to metallo-β-lactamases or Klebsiella pneumoniae carbapenemases (KPC), no specific inhibitor is available for the phenotypic detection of OXA-48. Molecular detection of bla OXA-48 is the “gold standard” but is not available in many laboratories. A few phenotypic assays have been described but have not been independently evaluated. The aim of this study was the systematic comparison of phenotypic tests and an immunochromatographic assay (ICT) for the detection of OXA-48/OXA-48-like carbapenemases and the development of an algorithm for reliable phenotypic detection of OXA-48. Four phenotypic tests (temocillin disk test, faropenem disk test, OXA-48 disk test, and high-inoculum [HI] OXA-48 disk test) and a new ICT (OXA-48 K -SeT) were compared by using a set of 166 Enterobacteriaceae isolates, including isolates producing OXA-48/OXA-48-like carbapenemases ( n = 84) or Ambler class A and B carbapenemases ( n = 41) and carbapenemase-negative isolates ( n = 41). The sensitivity and specificity for the different assays were 100% and 43.9% for temocillin, 57.1% and 98.8% for faropenem, 53.6% and 100% for the OXA-48 disk test, 98.8% and 97.6% for the HI OXA-48 disk test, and 100% and 100% for the ICT, respectively. The ICT displayed the highest sensitivity and specificity and was the most rapid assay, but it is more costly than phenotypic assays. Based on these results, a new algorithm incorporating temocillin, faropenem, and ICT which allows cost-effective detection of OXA-48 with 100% sensitivity and specificity was developed.

scholarly journals Evaluation of the New BD Max GC Real-Time PCR Assay, Analytically and Clinically as a Supplementary Test for the BD ProbeTec GC Qx Amplified DNA Assay, for Molecular Detection of Neisseria gonorrhoeae

2015 ◽  
Vol 53 (12) ◽  
pp. 3935-3937 ◽  
Author(s):  
Daniel Golparian ◽  
Stina Boräng ◽  
Martin Sundqvist ◽  
Magnus Unemo
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Real Time ◽  
Sensitivity And Specificity ◽  
Real Time Pcr ◽  
Molecular Detection ◽  
Analytical Sensitivity ◽  
Pcr Assay ◽  
Content Type ◽  
Dna Assay ◽  
Supplementary Test

The new BD Max GC real-time PCR assay showed high clinical and analytical sensitivity and specificity. It can be an effective and accurate supplementary test for the BD ProbeTec GC Qx amplified DNA assay, which had suboptimal specificity, and might also be used for initial detection ofNeisseria gonorrhoeae.

scholarly journals Carba NP as a simpler, rapid, cost-effective, and a more sensitive alternative to other phenotypic tests for detection of carbapenem resistance in routine diagnostic laboratories

2017 ◽  
Vol 9 (02) ◽  
pp. 100-103 ◽  
Author(s):  
Shivani Shinde ◽  
Rajarshi Gupta ◽  
Shweta S. Raut ◽  
Gita Nataraj ◽  
Preeti R. Mehta
Keyword(s):  
Sensitivity And Specificity ◽  
Carbapenem Resistance ◽  
Cost Effective ◽  
Confirmatory Test ◽  
Reference Test ◽  
Resistant Strains ◽  
Low Sensitivity ◽  
Sensitivity Specificity ◽  
Phenotypic Tests ◽  
Accuracy Rates

Abstract PURPOSE: Resistance to carbapenems due to carbapenemases has been increasingly noticed in Enterobacteriaceae. Clinical and Laboratory Standards Institute (CLSI) has recommended the latest Carba NP (CNP) test as a confirmatory test for carbapenemase production in Enterobacteriaceae. Low sensitivity of disk diffusion (DD) and modified Hodge test (MHT) may result in missing out of resistant strains which can adversely affect clinical management. The present study compares three phenotypic tests - CNP test, DD, and MHT for detection of carbapenemase production. MATERIALS AND METHODS: Four hundred consecutive, nonduplicate Enterobacteriaceae isolates were tested for carbapenem resistance using ertapenem disc (10 μg) by Kirby–Bauer DD method, MHT, and CNP. These tests were performed and interpreted as per the CLSI standards. CNP was considered to be the reference test for comparison. Sensitivity, specificity, and accuracy rates for ertapenem DD and MHT were calculated. RESULTS: One hundred and six out of 400 strains were positive by CNP test. Of the 294 CNP-negative strains, 28 were resistant by DD and 18 were resistant by MHT. Of the 106 CNP-positive strains, 82 were resistant and 16 were intermediate by DD while 76 were positive by MHT ertapenem DD had a sensitivity and specificity of 66.04% and 90.48%, respectively. Sensitivity and specificity of MHT were 54.72% and 93.88%, respectively. There was considerable discordance between all the three tests. CONCLUSION: As a rapid, simple, and cost-effective test with a greater capability greater to detect carbapenemase producers, CNP can be implemented in routine diagnostic laboratories, thereby benefiting patient care and antimicrobial stewardship.

scholarly journals Multicenter Clinical Evaluation of the Xpert GBS LB Assay for Detection of Group B Streptococcus in Prenatal Screening Specimens

2014 ◽  
Vol 53 (2) ◽  
pp. 443-448 ◽  
Author(s):  
Blake W. Buchan ◽  
Matthew L. Faron ◽  
DeAnna Fuller ◽  
Thomas E. Davis ◽  
Donna Mayne ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Clinical Evaluation ◽  
Gold Standard ◽  
Early Onset ◽  
Prenatal Screening ◽  
Molecular Diagnostic ◽  
Current Standard ◽  
Culture Methods ◽  
Content Type ◽  
Group B

Neonatal infection withStreptococcus agalactiae(group BStreptococcus[GBS]) is a leading cause of sepsis and meningitis in newborns. Recent guidelines have recommended universal screening of all pregnant women to identify those colonized with GBS and administration of peripartum prophylaxis to those identified as carriers to reduce the risk of early-onset GBS disease in neonates. Enriched culture methods are the current standard for prenatal GBS screening; however, the implementation of more sensitive molecular diagnostic tests may be able to further reduce the risk of early-onset GBS infection. We report a clinical evaluation of the Xpert GBS LB assay, a molecular diagnostic test for the identification of GBS from broth-enriched vaginal/rectal specimens obtained during routine prenatal screening. A total of 826 specimens were collected from women undergoing prenatal screening (35 to 37 weeks' gestation) and tested at one of three clinical centers. Each swab specimen was tested directly prior to enrichment using the Xpert GBS assay. Following 18 to 24 h of broth enrichment, each specimen was tested using the Xpert GBS LB assay and the FDA-cleared Smart GBS assay as a molecular diagnostic comparator. Results obtained using all three molecular tests were compared to those for broth-enriched culture as the gold standard. The sensitivity and specificity of the Xpert GBS LB assay were 99.0% and 92.4%, respectively, compared to those for the gold standard culture. The Smart GBS molecular test demonstrated sensitivity and specificity of 96.8% and 95.5%, respectively. The sensitivities of the two broth-enriched molecular methods were superior to those for direct testing of specimens using the Xpert GBS assay, which demonstrated sensitivity and specificity of 85.7% and 96.2%, respectively.

scholarly journals Evaluation of RNA extraction free method for detection of SARS-COV-2 in salivary samples for mass screening for COVID-19

2021 ◽  
Author(s):  
Sally A. Mahmoud ◽  
Esra Ibrahim ◽  
Subhashini Ganesan ◽  
Bhagyashree Thakre ◽  
Juliet G Teddy ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Gold Standard ◽  
Rna Extraction ◽  
High Sensitivity ◽  
High Specificity ◽  
Cost Effective ◽  
Kappa Coefficient ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Good Percentage

AbstractIn this current COVID - 19 pandemic, there is a dire need for cost effective and less time-consuming alternatives for SARS-COV-2 testing. The RNA extraction free method for detecting SARS-COV-2 in saliva is a promising option, this study found that it has high sensitivity (85.34%), specificity (95.04%) and was comparable to the gold standard nasopharyngeal swab. The method showed good percentage of agreement (kappa coefficient) 0.797 between salivary and NPS samples. However, there are variations in the sensitivity and specificity based on the RT-PCR kit used. The Thermo Fischer-Applied biosystems showed high sensitivity, PPV and NPV but also showed higher percentage of invalid reports. Whereas the BGI kit showed high specificity, better agreement (kappa coefficient) between the results of saliva and NPS samples and higher correlation between the Ct values of saliva and NPS samples. Thus, the RNA extraction free method for salivary sample serves as an effective alternative for SARS-CoV 2-testing.

scholarly journals THE COMPARATIVE STUDY TO DETECT RENAL & URINARY TRACT CALCULI (NEPHROLITHIASIS AND UROLITHIASIS) ON ULTRASOUND AND CT.

2021 ◽  
Vol 6 (5) ◽  
pp. 25-37
Author(s):  
Mahnoor Pracha ◽  
Amtullah Fatima ◽  
Najeebullah Alakozai ◽  
Azizullah Alakozai ◽  
Taiba Aslam ◽  
...  
Keyword(s):  
Urinary Tract ◽  
Sensitivity And Specificity ◽  
Gold Standard ◽  
Imaging Modality ◽  
Color Doppler ◽  
Cost Effective ◽  
Non Invasive ◽  
Ureteric Calculi ◽  
Urinary Tract Calculi ◽  
Ionizing Radiations

Background: Ultrasound is a non-invasive imaging modality, and it is cost effective while CT in invasive that uses ionizing radiations, yet it is difficult on ultrasound to diagnose calculi in ureter hence for evaluation of ureteric calculi CT scan is gold standard modality. Objective: To compare the detection of renal& urinary tract calculi (nephrolithiasis & urolithiasis) on ultrasound and CT. Material and methods: The data bases PubMed, ProQuest, and Google scholar and research gate were searched with the key words: nephrolithiasis on ultrasound and CT, sensitivity, specificity, from 2010 to 2021. For inclusion and exclusion of studies independently screened the titles and abstracts of full and related articles. Articles that had information about nephrolithiasis, urolithiasis at ultrasound and CT and its sensitivity and specificity were included. Results:  In total, 28 studies were found on renal & urinary tract calculi at ultrasound and computed tomography. This literature review demonstrates that computed tomography is characterized by high sensitivity and specificity in diagnosing renal, ureteric calculi while ultrasound has low sensitivity and specificity. Conclusions: Ultrasound is the best modality for imaging calculi within the kidney, a well hyper echoic mass with posterior acoustic shadow is identified as stone on gray scale, color Doppler can be used for demarcation of stone. At Color Doppler twinkling artifact appears around the calculi hence it can be differentiated by hyper echoic renal sinuses but this is crucially dependant on the size and anatomical position of the stone. The ultrasonic evaluation either overestimates or misinterprets the calculi size while CT gives an exact measurement, position with authentic sensitivity and specificity. Hence, CT is the gold standard for detection of renal calculi. Recommendation: Ultrasound is a non-invasive imaging modality and it is cost effective while CT in invasive that uses ionizing radiations, yet it is difficult on ultrasound to diagnose calculi in ureter hence for evaluation of ureteric calculi CT scan is gold standard modality.

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

2017 ◽  
Vol 55 (4) ◽  
pp. 1046-1055 ◽  
Author(s):  
Pranita D. Tamma ◽  
Belita N. A. Opene ◽  
Andrew Gluck ◽  
Krizia K. Chambers ◽  
Karen C. Carroll ◽  
...  
Keyword(s):  
Gold Standard ◽  
Boronic Acid ◽  
Retrospective Cohort ◽  
Turnaround Time ◽  
Content Type ◽  
Health Care Settings ◽  
Carbapenem Resistant ◽  
Synergy Test ◽  
Phenotypic Tests ◽  
Laboratory Workflow

ABSTRACT 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 ≥98% 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.

scholarly journals Evaluation of a New Phenotypic OXA-48 Disk Test for Differentiation of OXA-48 Carbapenemase-Producing Enterobacteriaceae Clinical Isolates

2015 ◽  
Vol 53 (4) ◽  
pp. 1245-1251 ◽  
Author(s):  
Athanassios Tsakris ◽  
Aggeliki Poulou ◽  
Pierre Bogaerts ◽  
Evangelia Dimitroulia ◽  
Spyros Pournaras ◽  
...  
Keyword(s):  
Boronic Acid ◽  
Content Type ◽  
Control Information ◽  
Class A ◽  
Class D ◽  
Phenotypic Method ◽  
Phenyl Boronic Acid ◽  
Phenotypic Methods ◽  
Esbl Producers ◽  
Disk Test

The current phenotypic methods for detecting carbapenemase-producingEnterobacteriaceae(CPE) allow differentiation between class A and B carbapenemases, but they cannot confirm in a single test class D OXA-48 carbapenemase producers. In this study, we evaluated a new phenotypic test, the OXA-48 disk test, which is based on an imipenem disk and two blank disks adjacent to the imipenem disk, loaded with the tested strain and impregnated with EDTA and EDTA plus phenyl boronic acid (PBA), respectively. The evaluation of the OXA-48 disk test was performed with 81 genotypically confirmed OXA-48-type-producingEnterobacteriaceaeisolates (41 extended-spectrum β-lactamase [ESBL] producers, 3 AmpC producers, and 37 non-ESBL, non-AmpC producers). To measure the specificity of the test, 173 genotypically confirmed OXA-48-negativeEnterobacteriaceaeisolates (57Klebsiella pneumoniaecarbapenemase [KPC] producers, 34 VIM producers, 23 KPC/VIM producers, 22 NDM producers, and 37 AmpC or ESBL producers and porin deficient) that were nonsusceptible to at least one carbapenem were chosen for testing. Using the imipenem disk and the distortion of the inhibition halo around both blank disks containing EDTA and EDTA/PBA, the test differentiated all but 3 of the 81 OXA-48 producers (sensitivity of 96.3%). The test was negative for OXA-48 production in all but 4 of the 173 carbapenem-nonsusceptible isolates producing other carbapenemases, AmpCs, or ESBLs (specificity of 97.7%). This evaluation shows that the OXA-48 disk test is an accurate phenotypic method for the direct differentiation of OXA-48-producingEnterobacteriaceae. Its use along with combined disk tests employing inhibitor-supplemented carbapenem disks might allow the differentiation of the currently known carbapenemase types inEnterobacteriaceaespecies and provide important infection control information.

scholarly journals Multicenter Evaluation of the Modified Carbapenem Inactivation Method and the Carba NP for Detection of Carbapenemase-Producing Pseudomonas aeruginosa and Acinetobacter baumannii

2017 ◽  
Vol 56 (1) ◽  
Author(s):  
Patricia J. Simner ◽  
J. Kristie Johnson ◽  
William B. Brasso ◽  
Karen Anderson ◽  
David R. Lonsway ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Acinetobacter Baumannii ◽  
Sensitivity And Specificity ◽  
Content Type ◽  
Class A ◽  
Carbapenem Resistant ◽  
Reliable Detection ◽  
Initial Comparison ◽  
The Mean ◽  
Mean Sensitivity

ABSTRACT The purpose of this study was to develop the modified carbapenem inactivation method (mCIM) for the detection of carbapenemase-producing Pseudomonas aeruginosa (CP-PA) and carbapenemase-producing Acinetobacter baumannii (CP-AB) and perform a multicenter evaluation of the mCIM and Carba NP tests for these nonfermenters. Thirty P. aeruginosa and 30 A. baumannii isolates previously characterized by whole-genome sequencing from the CDC-FDA Antibiotic Resistance Isolate Bank were evaluated, including CP isolates (Ambler class A, B, and D), non-carbapenemase-producing (non-CP) carbapenem-resistant isolates, and carbapenem-susceptible isolates. Initial comparison of a 1-μl versus 10-μl loop inoculum for the mCIM was performed by two testing sites and showed that 10 μl was required for reliable detection of carbapenemase production among P. aeruginosa and A. baumannii. Ten testing sites then evaluated the mCIM using a 10-μl loop inoculum. Overall, the mean sensitivity and specificity of the mCIM for detection of CP-PA across all 10 sites were 98.0% (95% confidence interval [CI], 94.3 to 99.6; range, 86.7 to 100) and 95% (95% CI, 89.8 to 97.7; range, 93.3 to 100), whereas the mean sensitivity and specificity among CP-AB were 79.8% (95% CI, 74.0 to 84.9; range, 36.3 to 95.7) and 52.9% (95% CI, 40.6 to 64.9; range, 28.6 to 100), respectively. At three sites that evaluated the performance of the Carba NP test using the same set of isolates, the mean sensitivity and specificity of the Carba NP test were 97.8% (95% CI, 88.2 to 99.9; range, 93.3 to 100) and 97.8% (95% CI, 88.2 to 99.9; range, 93.3 to 100) for P. aeruginosa and 18.8% (95% CI, 10.4 to 30.1; range, 8.7 to 26.1) and 100% (95% CI, 83.9 to 100; range, 100) for A. baumannii. Overall, we found both the mCIM and the Carba NP test to be accurate for detection of carbapenemase production among P. aeruginosa isolates and less reliable for use with A. baumannii isolates.

scholarly journals NG-Test Carba 5 for Rapid Detection of Carbapenemase-Producing Enterobacterales from Positive Blood Cultures

2019 ◽  
Vol 63 (5) ◽  
Author(s):  
Julie Takissian ◽  
Rémy A. Bonnin ◽  
Thierry Naas ◽  
Laurent Dortet
Keyword(s):  
Sensitivity And Specificity ◽  
Rapid Detection ◽  
Bloodstream Infections ◽  
Blood Cultures ◽  
Immunochromatographic Assay ◽  
Content Type

ABSTRACT The immunochromatographic assay, NG-test Carba 5 (NG Biotech), has been evaluated for detection of carbapenemase-producing Enterobacterales (CPE) from spiked blood cultures (n = 205). It detected and discriminated in less than 30 minutes KPC, IMP, VIM, NDM, and OXA-48-like producers with a sensitivity and specificity of 97.7% and 96.1%, respectively. Thus, it might help the rapid optimization of treatment of bloodstream infections due to CPE.

scholarly journals Detection of Carbapenemase-Producing Klebsiella pneumoniae and Escherichia coli Recovered from Clinical Specimens in Erbil City Kurdistan Region of Iraq

2019 ◽  
Vol 30 (2) ◽  
pp. 10
Author(s):  
Heshu Jalal Ahmed ◽  
Aryan R. Ganjo
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Molecular Detection ◽  
Antimicrobial Agents ◽  
Cost Effective ◽  
Drug Resistant ◽  
Diffusion Test ◽  
Detection Techniques ◽  
Carbapenem Resistant ◽  
Disk Test

Background: Carbapenems are usually the choice of antimicrobial agents in infections produced by Enterobacteriaceae bacteria-producing ESBL (extended spectrum β-lactamases). Carbapenemase production among clinical isolates of Enterobacteriaceae has been widely reported and Resistance to carbapenems group is generally due to production of Carbapenemases. Phenotypic determination and distinction of Carbapenemases in drug-resistant gram-negative is crucial for appropriate infection control. Materials and Methods: Carbapenemase production among Enterobacteriaceae isolates was identified phenotypically using a commercially available EDTA-combined disc diffusion test containing inhibitors to the various carbapenemase classes and Modified Hodge test (MHT). Results: A total of 98 Enterobacteriaceae isolates were included, 42(42.8%) were Multi-drug resistant (MDR), 27(27.5%) were XDR while 8(8.2%) exhibited pan-drug resistance (PDR). Of the 74 isolates of Escherichia coli and 24 Klebsiella pneumoniae that were positive for carbapenemase production, 12 (16.2%) and 9 (37.5%) were Metallo beta-lactamase (MBL) producers respectively, Hence, the overall prevalence of carbapenemase-producing Escherichia coli and Klebsiella pneumoniae in this study were 47.3% and 87.5%. Conclusion: Carbapenemase-producing Enterobacteriaceae was indeed recognized in our hospitals. The EDTA-combination disk test was a rapid, cost-effective and suitable method which will be able to identify and distinguish the carbapenem-resistant bacterial isolates within the hospitals especially when molecular detection techniques are not available.

Sign in / Sign up

Export Citation Format

Share Document