Validation of the Legipid® Bioalarm Legionella Assay

Abstract Legipid® Bioalarm Legionella is a test based on combined magnetic immunocapture and enzyme-immunoassay (CEIA) for the detection of Legionella pneumophila in water. Anti-L. pneumophila antibodies are immobilized on magnetic microspheres. Immunomagnetic analysis is applied to preconcentrated water samples in a final test volume of 9 mL. The method was compared with the standard culture method on both spiked and naturally contaminated water samples. The test was evaluated in potable, industrial, and natural water matrixes, according to the scope of the ISO 11731 reference method. These waters were tested with the target at levels ranging from low (10–99 CFU/mL) to high (100–999 CFU/mL); a Chi-square value of 1.8 indicated that there was no significant difference between the test and the reference method. The false-positive rate was 7%, and the false-negative rate 2%. For the inclusivity study, all 17 strains of L. pneumophila of different serogroups reacted with the test. For the exclusivity study, 17 strains of other Legionella species and 16 non-Legionella strains were tested. There were no cross-reactions with non-Legionella strains. L. beliardensis, L. adelaidensis, and one environmentally isolated Legionella sp. produced a positive result at high concentrations of 1800, 230, and 3900 CFU/mL, respectively. Agreement between the two methods was 95.9%.

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Comparison of the BAX System PCR Method to Brazil's Official Method for the Detection of Salmonella in Food, Water, and Environmental Samples

Journal of Food Protection ◽

10.4315/0362-028x-71.12.2442 ◽

2008 ◽

Vol 71 (12) ◽

pp. 2442-2447 ◽

Cited By ~ 4

Author(s):

INGRID BOESCHE TOMAZELLI ◽

JOSINETE BARROS de FREITAS ◽

LEANIA MARIA FABBI ◽

TEREZINHA AGNESE FILIPINI ◽

CLÁUDIA MARIA da SILVA ◽

...

Keyword(s):

Environmental Samples ◽

Limit Of Detection ◽

False Positive Rate ◽

False Negative ◽

False Negative Rate ◽

Reference Method ◽

Culture Method ◽

Official Method ◽

Positive Rate ◽

Pcr Method

A two-stage study compared the BAX system PCR method with the reference culture method used by the Brazilian Ministry of Agriculture and Food Supply for the detection of Salmonella in food, water, and environmental samples. In stage 1, fish matrix samples (n = 258) were spiked at several levels with Salmonella and a combination of Salmonella and non-Salmonella competitive organisms. Replicates were analyzed by the BAX system PCR method and the reference method with comparable results (sensitivity ≥ 97.5%, specificity ≥ 83.3%) from both methods at the limit of detection. In stage 2, a total of 1,988 samples with 70 product types were analyzed with both methods. Five laboratories were involved in this study, and the samples used were from routine analyses. The BAX system PCR method was shown to be comparable to the reference method, with a limit of detection of 1.0 to 2.0 CFU/25 g of sample. Analysis of the results obtained in stage 2 and in the combination of stages 1 and 2 for the BAX system showed the following performance: sensitivity ≥ 99.0%, specificity ≥ 97.2%, false-negative rate ≤ 1.1%, and false-positive rate ≤ 2.8%. Therefore, the BAX system appears to be equivalent to the reference method, with ≥ 97.3% agreement.

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RapidChek SELECT Salmonella

Journal of AOAC International ◽

10.1093/jaoac/92.6.1890 ◽

2009 ◽

Vol 92 (6) ◽

pp. 1890-1894 ◽

Cited By ~ 8

Author(s):

Mark T Muldoon ◽

Jingkun Li ◽

Meredith Sutzko ◽

Ann Christine Olsson-Allen ◽

George Teaney ◽

...

Keyword(s):

False Positive Rate ◽

Peanut Butter ◽

False Negative ◽

False Negative Rate ◽

Reference Method ◽

Salmonella Spp ◽

Chi Square ◽

Negative Results ◽

Significant Difference ◽

Positive Rate

Abstract RapidChek SELECT Salmonella was previously validated in the Performance Tested MethodsSM program for the detection of Salmonella spp. in raw ground chicken, chicken carcass rinse, sliced cooked turkey, and liquid eggs. The present matrix extension study conducted under the AOAC Research Institute Emergency Response Validation program compared the RapidChek SELECT Salmonella method to the U.S. Food and Drug Administration's Bacteriological Analytical Manual (FDA-BAM) method for the detection of Salmonella Typhimurium in peanut butter. Overall, 27 samples were found positive by the RapidChek SELECT Salmonella method and 27 were found to be positive by the reference method. All RapidChek SELECT Salmonella presumptive positives were confirmed positive by the cultural reference method; additionally, all presumptive negative results were confirmed negative by the cultural reference method. Accordingly 0 false-negative rate and 0 false-positive rate were found. No significant difference between the RapidCheck SELECT Salmonella and FDA-BAM reference method was found; calculated Chi-square was 0. Results indicate that a low level of Salmonella in peanut butter can be successfully recovered and detected in the minimum 24 h enrichment protocol.

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Singlepathr® Salmonella: Performance-Tested MethodSM 060401

Journal of AOAC International ◽

10.1093/jaoac/89.2.417 ◽

2006 ◽

Vol 89 (2) ◽

pp. 417-432 ◽

Cited By ~ 4

Author(s):

Lisa Thompson ◽

Charlotte Lindhardt ◽

Joseph Odumeru ◽

Joseph D Eifert

Keyword(s):

False Positive Rate ◽

False Negative ◽

False Negative Rate ◽

Reference Method ◽

Black Pepper ◽

Salmonella Spp ◽

Chi Square ◽

Qualitative Detection ◽

Significant Difference ◽

Positive Rate

Abstract Singlepath® Salmonella is an immunochromatographic (lateral flow) assay for the presumptive qualitative detection of Salmonella spp. in food. The AOAC Performance-Tested MethodSM study evaluated Singlepath Salmonella as an effective method for the detection of Salmonella spp. in the following selected foods: dried skimmed milk, black pepper, dried pet food, desiccated coconut, cooked peeled frozen prawns, raw ground beef, and raw ground turkey. When the foods were inoculated with Salmonella spp. at levels ranging from low 0.23–1.08 colony forming units (CFU)/25 g to high (2.3–6.0 CFU/25 g), a Chi-square value of 0.9 indicated that there was no significant difference between Singlepath Salmonella and the ISO 6579:2002 reference method. Singlepath Salmonella gave a false-positive rate of 7.3% and a false-negative rate of 2.5%. For the inclusivity study, all 105 Salmonella serovars reacted with Singlepath Salmonella. For the exclusivity study, 58 non-Salmonella spp. were tested. There were no cross-reactions with Singlepath Salmonella from these strains.

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Performance of Legiolert Test vs. ISO 11731 to Confirm Legionella pneumophila Contamination in Potable Water Samples

Pathogens ◽

10.3390/pathogens9090690 ◽

2020 ◽

Vol 9 (9) ◽

pp. 690 ◽

Cited By ~ 1

Author(s):

Maria Scaturro ◽

Matteo Buffoni ◽

Antonietta Girolamo ◽

Sandra Cristino ◽

Luna Girolamini ◽

...

Keyword(s):

Risk Assessment ◽

Legionella Pneumophila ◽

Water Samples ◽

Gold Standard ◽

Liquid Culture ◽

Potable Water ◽

Culture Method ◽

Alternative Methods ◽

Significant Difference

Detection and enumeration of Legionella in water samples is of great importance for risk assessment analysis. The plate culture method is the gold standard, but has received several well-known criticisms, which have induced researchers to develop alternative methods. The purpose of this study was to compare Legionella counts obtained by the analysis of potable water samples through the plate culture method and through the IDEXX liquid culture Legiolert method. Legionella plate culture, according to ISO 11731:1998, was performed using 1 L of water. Legiolert was performed using both the 10 mL and 100 mL Legiolert protocols. Overall, 123 potable water samples were analyzed. Thirty-seven (30%) of them, positive for L. pneumophila, serogroups 1 or 2–14 by plate culture, were used for comparison with the Legiolert results. The Legiolert 10 mL test detected 34 positive samples (27.6%) and the Legiolert 100 mL test detected 37 positive samples, 27.6% and 30% respectively, out of the total samples analyzed. No significant difference was found between either the Legiolert 10 mL and Legiolert 100 mL vs. the plate culture (p = 0.9 and p = 0.3, respectively) or between the Legiolert 10 mL and Legiolert 100 mL tests (p = 0.83). This study confirms the reliability of the IDEXX Legiolert test for Legionella pneumophila detection and enumeration, as already shown in similar studies. Like the plate culture method, the Legiolert assay is also suitable for obtaining isolates for typing purposes, relevant for epidemiological investigations.

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Evaluation of an Immunomagnetic Separation–Real-Time PCR Assay for the Rapid Detection of Salmonella in Meat

Journal of Food Protection ◽

10.4315/0362-028x-69.12.2896 ◽

2006 ◽

Vol 69 (12) ◽

pp. 2896-2901 ◽

Cited By ~ 27

Author(s):

ANGELIKA NOTZON ◽

REINER HELMUTH ◽

JOHANN BAUER

Keyword(s):

Real Time ◽

Real Time Pcr ◽

False Positive Rate ◽

False Negative ◽

False Negative Rate ◽

Reference Method ◽

Immunomagnetic Separation ◽

Pcr Assay ◽

Positive Rate ◽

Meat Samples

The aim of this study was the comparison of an immunomagnetic separation (IMS)–real-time PCR assay for the detection of Salmonella with the cultural reference method according to §35 of the German Law on Food and Commodities (LMBG, L 00.00.20:1998). The IMS–real-time PCR assay includes a nonselective preenrichment step, an IMS, DNA extraction, as well as DNA purification followed by hybridization probe–based real-time PCR analysis. An accurate comparability was achieved, because both methods analyzed the same preenrichment. The evaluation was carried out using both artificially and naturally contaminated meat samples. The IMS–real-time PCR assay provides a result after 12 to 13 h. Compared with the reference method and regarding artificially contaminated meat samples, the IMS–real-time PCR assay achieved a specificity of 80% (false-positive rate of 20%) and a sensitivity of 100% (false-negative rate of 0%). The relative accuracy was 94%. The detection limit of both methods was 10 CFU/25 g. The concordance indexκ defines the statistical accordance, was 0.85 and indicated the agreement of both methods on statistical criteria. Compared to the reference method and analyzing naturally contaminated meat samples (n = 491), the IMS–real-time PCR assay showed a specificity of 99.3% (false-positive rate of 0.7%) and a sensitivity of 83.7% (false-negative rate of 16.3%). The relative accuracy was 98%. The concordance index κ had a value of 0.87 and highlighted the statistical agreement of both methods. In conclusion, the IMS–real-time PCR assay is suitable as specific, sensitive, and rapid screening method for the detection of Salmonella from meat.

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Method Modification of the Legipid®Legionella Fast Detection Test Kit

Journal of AOAC International ◽

10.5740/jaoacint.14-029 ◽

2014 ◽

Vol 97 (5) ◽

pp. 1403-1409 ◽

Cited By ~ 5

Author(s):

Guillermo Rodríguez Albalat ◽

Begoña Bedrina Broch ◽

Marisa Jiménez Bono

Keyword(s):

Legionella Pneumophila ◽

Reference Method ◽

Culture Method ◽

Test Method ◽

Magnetic Microspheres ◽

Test Portion ◽

Relative Level ◽

Fast Detection ◽

Test Kit ◽

Optical Reader

Abstract Legipid®Legionella Fast Detection is a test based on combined magnetic immunocapture and enzyme-immunoassay (CEIA) for the detection of Legionella in water. The test is based on the use of anti-Legionella antibodies immobilized on magnetic microspheres. Target microorganism is preconcentrated by filtration. Immunomagnetic analysis is applied on these preconcentrated water samples in a final test portion of 9 mL. The test kit was certified by the AOAC Research Institute as Performance Tested MethodSM (PTM) No. 111101 in a PTM validation which certifies the performance claims of the test method in comparison to the ISO reference method 11731-1998 and the revision 11731-2004 “Water Quality: Detection and Enumeration of Legionella pneumophila” in potable water, industrial water, and waste water. The modification of this test kit has been approved. The modification includes increasing the target analyte from L. pneumophila to Legionella species and adding an optical reader to the test method. In this study, 71 strains of Legionella spp. other than L. pneumophila were tested to determine its reactivity with the kit based on CEIA. All the strains of Legionella spp. tested by the CEIA test were confirmed positive by reference standard method ISO 11731. This test (PTM 111101) has been modified to include a final optical reading. A methods comparison study was conducted to demonstrate the equivalence of this modification to the reference culture method. Two water matrixes were analyzed. Results show no statistically detectable difference between the test method and the reference culture method for the enumeration of Legionella spp. The relative level of detection was 93 CFU/volume examined (LOD50). For optical reading, the LOD was 40 CFU/volume examined and the LOQ was 60 CFU/volume examined. Results showed that the test Legipid Legionella Fast Detection is equivalent to the reference culture method for the enumeration of Legionella spp.

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Comparative study of ultrasonographic findings with the operative findings of biliary surgery

Journal of Surgical Sciences ◽

10.3329/jss.v22i1.44011 ◽

2020 ◽

Vol 22 (1) ◽

pp. 25-29

Author(s):

Zubayer Ahmad ◽

Mohammad Ali ◽

Kazi lsrat Jahan ◽

ABM Khurshid Alam ◽

G M Morshed

Keyword(s):

Bile Duct ◽

Common Bile Duct ◽

Imaging Modality ◽

False Positive Rate ◽

Gallstone Disease ◽

False Negative ◽

False Negative Rate ◽

Biliary Disease ◽

Biliary Surgery ◽

Operative Findings

Background: Biliary disease is one of the most common surgical problems encountered all over the world. Ultrasound is widely accepted for the diagnosis of biliary system disease. However, it is a highly operator dependent imaging modality and its diagnostic success is also influenced by the situation, such as non-fasting, obesity, intestinal gas. Objective: To compare the ultrasonographic findings with the peroperative findings in biliary surgery. Methods: This prospective study was conducted in General Hospital, comilla between the periods of July 2006 to June 2008 among 300 patients with biliary diseases for which operative treatment is planned. Comparison between sonographic findings with operative findings was performed. Results: Right hypochondriac pain and jaundice were two significant symptoms (93% and 15%). Right hypochondriac tenderness, jaundice and palpable gallbladder were most valuable physical findings (respectively, 40%, 15% and 5%). Out of 252 ultrasonically positive gallbladder, stone were confirmed in 249 cases preoperatively. Sensitivity of USG in diagnosis of gallstone disease was 100%. There was, however, 25% false positive rate detection. Specificity was, however, 75% in this case. USG could demonstrate stone in common bile duct in only 12 out of 30 cases. Sensitivity of the test in diagnosing common bile duct stone was 40%, false negative rate 60%. In the series, ultrasonography sensitivity was 100% in diagnosing stone in cystic duct. USG could detect with relatively good but less sensitivity the presence of chronic cholecystitis (92.3%) and worm inside gallbladder (50%). Conclusion: Ultrasonography is the most important investigation in the diagnosis of biliary disease and a useful test for patients undergoing operative management for planning and anticipating technical difficulties. Journal of Surgical Sciences (2018) Vol. 22 (1): 25-29

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Effects of Previous Surgery on the Detection of Sentinel Nodes in Women With Vulvar Cancer

International Journal of Gynecological Cancer ◽

10.1097/igc.0b013e31822dbe3c ◽

2011 ◽

Vol 21 (9) ◽

pp. 1679-1683 ◽

Cited By ~ 10

Author(s):

Tessa A. Ennik ◽

David G. Allen ◽

Ruud L.M. Bekkers ◽

Simon E. Hyde ◽

Peter T. Grant

Keyword(s):

Vulvar Cancer ◽

False Negative ◽

False Negative Rate ◽

Blue Dye ◽

Previous Surgery ◽

Detection Rates ◽

Reliable Technique ◽

Appearance Time ◽

Negative Rate ◽

Significant Difference

BackgroundThere is a growing interest to apply the sentinel node (SN) procedure in the treatment of vulvar cancer. Previous vulvar surgery might disrupt lymphatic patterns and thereby decrease SN detection rates, lengthen scintigraphic appearance time (SAT), and increase SN false-negative rate. The aims of this study were to evaluate the SN detection rates at the Mercy Hospital for Women in Melbourne and to investigate whether previous vulvar surgery affects SN detection rates, SAT, and SN false-negative rate.MethodsData on all patients with vulvar cancer who underwent an SN procedure (blue dye, technetium, or combined technique) from November 2000 to July 2010 were retrospectively collected.ResultsSixty-five SN procedures were performed. Overall detection rate was 94% per person and 80% per groin. Detection rates in the group of patients who underwent previous excision of the primary tumor were not lower compared with the group without previous surgery or with just an incisional biopsy. There was no statistical significant difference in SAT between the previous excision group and the other patients. None of the patients with a false-negative SN had undergone previous excision.ConclusionsResults indicate that previous excision of a primary vulvar malignancy does not decrease SN detection rates or increase SN false-negative rate. Therefore, the SN procedure appears to be a reliable technique in patients who have previously undergone vulvar surgery. Previous excision did not significantly lengthen SAT, but the sample size in this subgroup analysis was small.

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Preliminary Results of MyCog, a Brief Assessment for the Detection of Cognitive Impairment in Primary Care

Innovation in Aging ◽

10.1093/geroni/igaa057.833 ◽

2020 ◽

Vol 4 (Supplement_1) ◽

pp. 259-260

Author(s):

Laura Curtis ◽

Lauren Opsasnick ◽

Julia Yoshino Benavente ◽

Cindy Nowinski ◽

Rachel O’Conor ◽

...

Keyword(s):

Primary Care ◽

Cognitive Impairment ◽

Cognitive Aging ◽

False Positive ◽

False Positive Rate ◽

False Negative ◽

False Negative Rate ◽

Self Report ◽

Card Sorting ◽

Primary Care Settings

Abstract Early detection of Cognitive impairment (CI) is imperative to identify potentially treatable underlying conditions or provide supportive services when due to progressive conditions such as Alzheimer’s Disease. While primary care settings are ideal for identifying CI, it frequently goes undetected. We developed ‘MyCog’, a brief technology-enabled, 2-step assessment to detect CI and dementia in primary care settings. We piloted MyCog in 80 participants 65 and older recruited from an ongoing cognitive aging study. Cases were identified either by a documented diagnosis of dementia or mild cognitive impairment (MCI) or based on a comprehensive cognitive battery. Administered via an iPad, Step 1 consists of a single self-report item indicating concern about memory or other thinking problems and Step 2 includes two cognitive assessments from the NIH Toolbox: Picture Sequence Memory (PSM) and Dimensional Change Card Sorting (DCCS). 39%(31/80) participants were considered cognitively impaired. Those who expressed concern in Step 1 (n=52, 66%) resulted in a 37% false positive and 3% false negative rate. With the addition of the PSM and DCCS assessments in Step 2, the paradigm demonstrated 91% sensitivity, 75% specificity and an area under the ROC curve (AUC)=0.82. Steps 1 and 2 had an average administration time of <7 minutes. We continue to optimize MyCog by 1) examining additional items for Step 1 to reduce the false positive rate and 2) creating a self-administered version to optimize use in clinical settings. With further validation, MyCog offers a practical, scalable paradigm for the routine detection of cognitive impairment and dementia.

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Ultrasound guided needle biopsy of axilla to evaluate nodal metastasis after preoperative systemic therapy in cohort of 106 breast cancers enriched with BRCA1/2 pathogenic variant carriers

Hereditary Cancer in Clinical Practice ◽

10.1186/s13053-021-00187-w ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Baiba Līcīte ◽

Arvīds Irmejs ◽

Jeļena Maksimenko ◽

Pēteris Loža ◽

Genādijs Trofimovičs ◽

...

Keyword(s):

Breast Cancer ◽

Systemic Therapy ◽

False Positive Rate ◽

False Negative ◽

False Negative Rate ◽

Axillary Node ◽

Pathogenic Variant ◽

Axillary Lymph ◽

Ultrasound Guided ◽

Node Positive

Abstract Background Aim of the study is to evaluate the role of ultrasound guided fine needle aspiration cytology (FNAC) in the restaging of node positive breast cancer after preoperative systemic therapy (PST). Methods From January 2016 – October 2020 106 node positive stage IIA-IIIC breast cancer cases undergoing PST were included in the study. 18 (17 %) were carriers of pathogenic variant in BRCA1/2. After PST restaging of axilla was performed with ultrasound and FNAC of the marked and/or the most suspicious axillary node. In 72/106 cases axilla conserving surgery and in 34/106 cases axillary lymph node dissection (ALND) was performed. Results False Positive Rate (FPR) of FNAC after PST in whole cohort and BRCA1/2 positive subgroup is 8 and 0 % and False Negative Rate (FNR) – 43 and 18 % respectively. Overall Sensitivity − 55 %, specificity- 93 %, accuracy 70 %. Conclusion FNAC after PST has low FPR and is useful to predict residual axillary disease and to streamline surgical decision making regarding ALND both in BRCA1/2 positive and negative subgroups. FNR is high in overall cohort and FNAC alone are not able to predict ypCR and omission of further axillary surgery. However, FNAC performance in BRCA1/2 positive subgroup is more promising and further research with larger number of cases is necessary to confirm the results.

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