Analysis of the VIDAS® Staph Enterotoxin III (SET3) for Detection of Staphylococcal Enterotoxins G, H, and I in Foods

2018 ◽  
Vol 101 (5) ◽  
pp. 1482-1489 ◽  
Author(s):  
Jennifer M Hait ◽  
Angela T Nguyen ◽  
Sandra M Tallent

Abstract Background: Staphylococcal food poisoning (SFP) frequently causes illnesses worldwide. SFP occurs from the ingestion of staphylococcal enterotoxins (SEs) preformed in foods by enterotoxigenic strains of Staphylococcus species, primarily S. aureus. SEG, SEH, and SEI induce emesis and have been implicated in outbreaks. Immunological-based methods are deemed the most practical methods for the routine analysis of SEs in foods given their ease of use, sensitivity, specificity, and commercial availability. These kits are routinely used to test for SEA-SEE. However, only recently has a kit been developed to detect SEG, SEH, and SEI. Objective: Our research examined the performance of the novel VIDAS® Staph Enterotoxin III (SET3) for the detection of staphylococcal enterotoxins SEG, SEH, and SEI in foods. Methods: Here we assess the sensitivity and specificity of SET3 using duplicate test portions of six foods at varying concentrations of inclusivity and exclusivity inocula: pure SEG, SEH, SEI, S. aureus strain extracts positive for seg, seh, and sei, as well as SEA, SEB, SEC, SED, and SEE. Results: The overall detection limit was less than 2.09 ng/mL for foods inoculated with SEG, SEH, and SEI, with no cross reactivity observed. Highlights: Integrating concurrent testing to detect the presence of SEA–SEE and SEG–SEI utilizing the SET3 along with the VIDAS SET2, Ridascreen® SET total, or other comparable kits will be instrumental for the future food assessments in our laboratory and may become the new standard for SE analysis of foods.

2021 ◽  
Vol 12 ◽  
Author(s):  
Hua Jiang ◽  
Kan Wang ◽  
Muxia Yan ◽  
Qian Ye ◽  
Xiaojing Lin ◽  
...  

Food safety and foodborne infections and diseases have been a leading hotspot in public health, and methicillin-resistant Staphylococcus aureus (MRSA) has been recently documented to be an important foodborne pathogen, in addition to its recognition to be a leading clinical pathogen for some decades. Standard identification for MRSA has been commonly performed in both clinical settings and food routine detection; however, most of such so-called “standards,” “guidelines,” or “gold standards” are incapable of detecting viable but non-culturable (VBNC) cells. In this study, two major types of staphylococcal food poisoning (SFP), staphylococcal enterotoxins A (sea) and staphylococcal enterotoxins B (seb), as well as the panton-valentine leucocidin (pvl) genes, were selected to develop a cross-priming amplification (CPA) method. Limit of detection (LOD) of CPA for sea, seb, and pvl was 75, 107.5, and 85 ng/μl, indicating that the analytical sensitivity of CPA is significantly higher than that of conventional PCR. In addition, a rapid VBNC cells detection method, designated as PMA-CPA, was developed and further applied. PMA-CPA showed significant advantages when compared with PCR assays, in terms of rapidity, sensitivity, specificity, and accuracy. Compared with conventional VBNC confirmation methods, the PMA-CPA showed 100% accordance, which had demonstrated that the PMA-CPA assays were capable of detecting different toxins in MRSA in VBNC state. In conclusion, three CPA assays were developed on three important toxins for MRSA, and in combination with PMA, the PMA-CPA assay was capable of detecting virulent gene expression in MRSA in the VBNC state. Also, the above assays were further applied to real samples. As concluded, the PMA-CPA assay developed in this study was capable of detecting MRSA toxins in the VBNC state, representing first time the detection of toxins in the VBNC state.


Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 130
Author(s):  
Cécile Féraudet Tarisse ◽  
Céline Goulard-Huet ◽  
Yacine Nia ◽  
Karine Devilliers ◽  
Dominique Marcé ◽  
...  

Staphylococcal food poisoning (SFP) is one of the most common foodborne diseases worldwide, resulting from the ingestion of staphylococcal enterotoxins (SEs), primarily SE type A (SEA), which is produced in food by enterotoxigenic strains of staphylococci, mainly S. aureus. Since newly identified SEs have been shown to have emetic properties and the genes encoding them have been found in food involved in poisoning outbreaks, it is necessary to have reliable tools to prove the presence of the toxins themselves, to clarify the role played by these non-classical SEs, and to precisely document SFP outbreaks. We have produced and characterized monoclonal antibodies directed specifically against SE type G, H or I (SEG, SEH or SEI respectively) or SEA. With these antibodies, we have developed, for each of these four targets, highly sensitive, specific, and reliable 3-h sandwich enzyme immunoassays that we evaluated for their suitability for SE detection in different matrices (bacterial cultures of S. aureus, contaminated food, human samples) for different purposes (strain characterization, food safety, biological threat detection, diagnosis). We also initiated and described for the first time the development of monoplex and quintuplex (SEA, SE type B (SEB), SEG, SEH, and SEI) lateral flow immunoassays for these new staphylococcal enterotoxins. The detection limits in buffer were under 10 pg/mL (0.4 pM) by enzyme immunoassays and at least 300 pg/mL (11 pM) by immunochromatography for all target toxins with no cross-reactivity observed. Spiking studies and/or bacterial supernatant analysis demonstrated the applicability of the developed methods, which could become reliable detection tools for the routine investigation of SEG, SEH, and SEI.


Infection ◽  
2021 ◽  
Author(s):  
Ali Hamady ◽  
JinJu Lee ◽  
Zuzanna A. Loboda

Abstract Objectives The coronavirus disease 2019 (COVID-19), caused by the novel betacoronavirus severe acute respiratory syndrome 2 (SARS-CoV-2), was declared a pandemic in March 2020. Due to the continuing surge in incidence and mortality globally, determining whether protective, long-term immunity develops after initial infection or vaccination has become critical. Methods/Results In this narrative review, we evaluate the latest understanding of antibody-mediated immunity to SARS-CoV-2 and to other coronaviruses (SARS-CoV, Middle East respiratory syndrome coronavirus and the four endemic human coronaviruses) in order to predict the consequences of antibody waning on long-term immunity against SARS-CoV-2. We summarise their antibody dynamics, including the potential effects of cross-reactivity and antibody waning on vaccination and other public health strategies. At present, based on our comparison with other coronaviruses we estimate that natural antibody-mediated protection for SARS-CoV-2 is likely to last for 1–2 years and therefore, if vaccine-induced antibodies follow a similar course, booster doses may be required. However, other factors such as memory B- and T-cells and new viral strains will also affect the duration of both natural and vaccine-mediated immunity. Conclusion Overall, antibody titres required for protection are yet to be established and inaccuracies of serological methods may be affecting this. We expect that with standardisation of serological testing and studies with longer follow-up, the implications of antibody waning will become clearer.


2012 ◽  
Vol 87 (3) ◽  
pp. 1400-1410 ◽  
Author(s):  
Donald M. Carter ◽  
Chalise E. Bloom ◽  
Eduardo J. M. Nascimento ◽  
Ernesto T. A. Marques ◽  
Jodi K. Craigo ◽  
...  

ABSTRACTIndividuals <60 years of age had the lowest incidence of infection, with ∼25% of these people having preexisting, cross-reactive antibodies to novel 2009 H1N1 influenza. Many people >60 years old also had preexisting antibodies to novel H1N1. These observations are puzzling because the seasonal H1N1 viruses circulating during the last 60 years were not antigenically similar to novel H1N1. We therefore hypothesized that a sequence of exposures to antigenically different seasonal H1N1 viruses can elicit an antibody response that protects against novel 2009 H1N1. Ferrets were preinfected with seasonal H1N1 viruses and assessed for cross-reactive antibodies to novel H1N1. Serum from infected ferrets was assayed for cross-reactivity to both seasonal and novel 2009 H1N1 strains. These results were compared to those of ferrets that were sequentially infected with H1N1 viruses isolated prior to 1957 or more-recently isolated viruses. Following seroconversion, ferrets were challenged with novel H1N1 influenza virus and assessed for viral titers in the nasal wash, morbidity, and mortality. There was no hemagglutination inhibition (HAI) cross-reactivity in ferrets infected with any single seasonal H1N1 influenza viruses, with limited protection to challenge. However, sequential H1N1 influenza infections reduced the incidence of disease and elicited cross-reactive antibodies to novel H1N1 isolates. The amount and duration of virus shedding and the frequency of transmission following novel H1N1 challenge were reduced. Exposure to multiple seasonal H1N1 influenza viruses, and not to any single H1N1 influenza virus, elicits a breadth of antibodies that neutralize novel H1N1 even though the host was never exposed to the novel H1N1 influenza viruses.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yoshihiro Osawa ◽  
Kaho Nomura ◽  
Yoshifumi Kimira ◽  
Seiji Kushibe ◽  
Ken-ichi Takeyama ◽  
...  

AbstractActive collagen oligopeptides (ACOP) are bioactive collagen-derived peptides detected by a recently-established ELISA. To facilitate studies of the function and metabolism of these products, this study aims to determine which of these peptides is recognized by a novel anti-ACOP antibody used in this ELISA. We then investigate the effect of collagen peptide (CP) ingestion and exercise on urinary ACOP concentrations in a cohort of university student athletes using colorimetric, LC–MS/MS, and ELISA. We observed that the antibody showed strong cross-reactivity to Pro-Hyp and Gly-Pro-Hyp and weak cross-reactivity to commercial CP. CP ingestion increased the urinary level of ACOP over time, which correlated highly with urinary levels of peptide forms of Hyp and Pro-Hyp. Physical activity significantly decreased the urinary ACOP level. This study demonstrates changes in urinary ACOP following oral CP intake and physical activity using ELISA with the novel anti-ACOP antibody. Thus, ACOP may be useful as a new biomarker for collagen metabolism.


2021 ◽  
pp. 112972982110087
Author(s):  
Junren Kang ◽  
Wenyan Sun ◽  
Hailong Li ◽  
En ling Ma ◽  
Wei Chen

Background: The Michigan Risk Score (MRS) was the only predicted score for peripherally inserted central venous catheters (PICC) associated upper extremity venous thrombosis (UEVT). Age-adjusted D-dimer increased the efficiency for UEVT. There were no external validations in an independent cohort. Method: A retrospective study of adult patients with PICC insertion was performed. The primary objective was to evaluate the performance of the MRS and age-adjusted D-dimer in estimating risk of PICC-related symptomatic UEVT. The sensitivity, specificity and areas under the receiver operating characteristics (ROC) of MRS and age-adjusted D-dimer were calculated. Results: Two thousand one hundred sixty-three patients were included for a total of 206,132 catheter days. Fifty-six (2.6%) developed PICC-UEVT. The incidences of PICC-UEVT were 4.9% for class I, 7.5% for class II, 2.2% for class III, 0% for class IV of MRS ( p = 0.011). The incidences of PICC-UEVT were 4.5% for D-dimer above the age-adjusted threshold and 1.5% for below the threshold ( p = 0.001). The areas under ROC of MRS and age-adjusted D-dimer were 0.405 (95% confidence interval (CI) 0.303–0.508) and 0.639 (95% CI 0.547–0.731). The sensitivity and specificity of MRS were 0.82 (95% CI, 0.69–0.91), 0.09 (95% CI, 0.08–0.11), respectively. The sensitivity and specificity of age-adjusted D-dimer were 0.64 (95% CI, 0.46–0.79) and 0.64 (95% CI, 0.61–0.66), respectively. Conclusions: MRS and age-adjusted D-dimer have low accuracy to predict PICC-UEVT. Further studies are needed.


2021 ◽  
Vol 357 ◽  
pp. 109366
Author(s):  
Kaoru Umeda ◽  
Hisaya K. Ono ◽  
Takayuki Wada ◽  
Daisuke Motooka ◽  
Shota Nakamura ◽  
...  

2017 ◽  
Vol 21 (1) ◽  
Author(s):  
Zeynep Cetiner-Alpay ◽  
Fatma Kulali ◽  
Aslihan Semiz-Oysu ◽  
Yasar Bukte ◽  
Kamil Ozdil

Background: Although endoscopic retrograde cholangiopancreatography (ERCP) is accepted as the gold standard, there is a place for magnetic resonance cholangiopancreatography (MRCP) and diffusion-weighted imaging (DWI) in the diagnosis of obstructive biliary disorders.Aim: To compare the findings of MRCP with ERCP in patients with obstructive biliary disorders and to investigate the diagnostic efficacy of MRCP combined with DWI.Study design: Retrospective, analytic, cross-sectional study.Methods: The MRCP images of 126 patients who underwent both MRCP and ERCP owing to biliary obstruction were reviewed. Nine patients were excluded because of incomplete diagnostic workup or a long period (>3 months) between MRCP and ERCP. Ninety-two patients underwent DWI, which was also evaluated. The sensitivity, specificity and accuracy of MRCP and DWI were analysed.Results: The sensitivity, specificity and accuracy of MRCP according to ERCP results as the gold standard was 97%, 71% and 93% for assessment of biliary dilatation; 100%, 94.7% and 97.5% for the diagnosis of choledocholithiasis; 93.7%, 100% and 99% for the identification of benign strictures; 100%, 100% and 100% for the diagnosis of malignant tumours; and 100%, 100% and 100% for the detection of complicated hydatid cysts; respectively. The sensitivity and specificity of DWI for the diagnosis of malignant tumour was 100%. In the detection of choledocholithiasis, the sensitivity and specificity of DWI was 70.8% and 100%.Conclusions: MRCP is an alternative, non-invasive, diagnostic modality, comparable with ERCP for the evaluation of pancreaticobiliary diseases. DWI can be helpful for diagnosis of choledocholithiasis and tumours.


2017 ◽  
Vol 20 (2) ◽  
pp. 122-127 ◽  
Author(s):  
Saverio Paltrinieri ◽  
Marco Fossati ◽  
Valentina Menaballi

Objectives The objective of this study was to evaluate the diagnostic performances of manual and instrumental measurement of reticulocyte percentage (Ret%), reticulocyte number (Ret#) and reticulocyte production index (RPI) to differentiate regenerative anaemia (RA) from non-regenerative anaemia (NRA) in cats. Methods Data from 106 blood samples from anaemic cats with manual counts (n = 74; 68 NRA, six RA) or instrumental counts of reticulocytes (n = 32; 25 NRA, seven RA) collected between 1995 and 2013 were retrospectively analysed. Sensitivity, specificity and positive likelihood ratio (LR+) were calculated using either cut-offs reported in the literature or cut-offs determined from receiver operating characteristic (ROC) curves. Results All the reticulocyte parameters were significantly higher in cats with RA than in cats with NRA. All the ROC curves were significantly different ( P <0.001) from the line of no discrimination, without significant differences between the three parameters. Using the cut-offs published in literature, the Ret% (cut-off: 0.5%) was sensitive (100%) but not specific (<75%), the RPI (cut-off: 1.0) was specific (>92%) but not sensitive (<15%), and the Ret# (cut-off: 50 × 10³/µl) had a sensitivity and specificity >80% and the highest LR+ (manual count: 14; instrumental count: 6). For all the parameters, sensitivity and specificity approached 100% using the cut-offs determined by the ROC curves. These cut-offs were higher than those reported in the literature for Ret% (manual: 1.70%; instrumental: 3.06%), lower for RPI (manual: 0.39; instrumental: 0.59) and variably different, depending on the method (manual: 41 × 10³/µl; instrumental: 57 × 10³/µl), for Ret#. Using these cut-offs, the RPI had the highest LR+ (manual: 22.7; instrumental: 12.5). Conclusions and relevance This study indicated that all the reticulocyte parameters may confirm regeneration when the pretest probability is high, while when this probability is moderate, RA should be identified using the RPI providing that cut-offs <1.0 are used.


2005 ◽  
Vol 71 (5) ◽  
pp. 2793-2795 ◽  
Author(s):  
Tetsuya Ikeda ◽  
Naoto Tamate ◽  
Keiji Yamaguchi ◽  
Sou-ichi Makino

ABSTRACT It was believed that food poisoning in Osaka in 2000 was due to small amounts of staphylococcal enterotoxin A (SEA) in reconstituted milk. Results of this study clearly indicate that SEH was also present in the raw material of reconstituted milk, indicating that the food poisoning was caused by multiple staphylococcal enterotoxins.


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