ABSTRACT
Individual-level assessments of wild animal health, vital rates, and foraging ecology are critical for understanding population-wide impacts of exposure to stressors. Large whales face multiple stressors, including, but not limited to, ocean noise, pollution, and ship strikes. Because baleen is a continuously growing keratinized structure, serial extraction, and quantification of hormones and stable isotopes along the length of baleen provide a historical record of whale physiology and foraging ecology. Furthermore, baleen analysis enables the investigation of dead specimens, even decades later, allowing comparisons between historic and modern populations. Here, we examined baleen of five sub-adult gray whales and observed distinct patterns of oscillations in δ15N values along the length of their baleen plates which enabled estimation of baleen growth rates and differentiation of isotopic niche widths of the whales during wintering and summer foraging. In contrast, no regular patterns were apparent in δ13C values. Prolonged elevation of cortisol in four individuals before death indicates that chronic stress may have impacted their health and survival. Triiodothyronine (T3) increased over months in the whales with unknown causes of death, simultaneous with elevations in cortisol, but both hormones remained stable in the one case of acute death attributed to killer whale predation. This parallel elevation of cortisol and T3 challenges the classic understanding of their interaction and might relate to increased energetic demands during exposure to stressors. Reproductive hormone profiles in subadults did not show cyclical trends, suggesting they had not yet reached sexual maturity. This study highlights the potential of baleen analysis to retrospectively assess gray whales' physiological status, exposure to stressors, reproductive status, and foraging ecology in the months or years leading up to their death, which can be a useful tool for conservation diagnostics to mitigate unusual mortality events.
Subject(s)
Endocrinology , Whales , Animals , Hydrocortisone , Longitudinal Studies , Retrospective StudiesABSTRACT
Clostridioides difficile is the most important cause of healthcare-associated diarrhea in the United States. The high incidence and recurrence rates of C. difficile infection (CDI), associated with high morbidity and mortality, pose a public health challenge. Although antibiotics targeting C. difficile bacteria are the first treatment choice, antibiotics also disrupt the indigenous gut flora and, therefore, create an environment that is favorable for recurrent CDI. The challenge of treating CDI is further exacerbated by the rise of antibiotic-resistant strains of C. difficile, placing it among the top five most urgent antibiotic resistance threats in the USA. The evolution of antibiotic resistance in C. difficile involves the acquisition of new resistance mechanisms, which can be shared among various bacterial species and different C. difficile strains within clinical and community settings. This review provides a summary of commonly used diagnostic tests and antibiotic treatment strategies for CDI. In addition, it discusses antibiotic treatment and its resistance mechanisms. This review aims to enhance our current understanding and pinpoint knowledge gaps in antimicrobial resistance mechanisms in C. difficile, with an emphasis on CDI therapies.
ABSTRACT
Anurans (frogs and toads) expelled urine when handled and it could provide insights into their physiological status. However, storage, preservation and transportation are often challenging. The study aimed to standardize and validate a field method for short-term storage and preserve of anuran urine samples using Whatman filter papers. To examine the efficacy of storage conditions and type of papers, urinary based enzyme immunoassays were used to measure progesterone and testosterone hormone metabolites. High-Performance Liquid Chromatography was performed and revealed immunoreactive progesterone and testosterone metabolites in the urine samples. Urinary hormone metabolites concentration stored in filter paper at room temperature and control samples stored in -20°C for the same period were similar. Whatman grade 50 was found to be more suitable for storage of hormones than grade 3 paper for the experiments performed.â¢A cheap and simple storage method for storage of anuran urine in field conditions using filter papers.â¢Anuran urine could be preserved and transported under ambient conditions without significant changes and loss of hormones.â¢This method would facilitate the endocrine monitoring of anurans in remote areas where limited logistics are available.
ABSTRACT
BACKGROUND: Lyme disease (LD) is emerging in many parts of central and eastern Canada. Serological testing is most commonly used to support laboratory diagnosis of LD. Standard two-tiered testing (STTT) for LD involves detection of Borrelia burgdorferi antibodies using an enzyme immunoassay (EIA) followed by IgM and/or IgG immunoblots. However, improved sensitivity has been demonstrated using a modified two-tiered testing (MTTT) approach, in which a second EIA instead of the traditional immunoblot is used. This article summarises the evidence supporting the MTTT versus STTT for laboratory diagnosis of LD in Canada. METHODS: Peer reviewed literature on the sensitivity and specificity of different EIAs were compared by Canadian experts in LD diagnostic for MTTT vs STTT in patients with clinical history of LD residing in LD endemic areas or in samples from the LD serum repository. RESULTS: The MTTT approach consistently demonstrated improved sensitivity to detect early infections with B. burgdorferi and also maintained high specificity vs STTT. CONCLUSION: Diagnostic improvements in sensitivity of LD testing without significant loss of specificity have been consistently reported when MTTT is compared with STTT in studies conducted in highly LD endemic regions. Our working group agrees with the recommendation by the United States Centers for Disease Control that serological testing for LD using MTTT is an acceptable alternative to STTT. This recommendation is contingent on development and implementation of comprehensive validation studies on the performance of MTTT vs STTT within the Canadian context, including evaluation of the test performance in areas of low endemicity for LD.
ABSTRACT
The use of enzyme immunoassays to screen for toxins A and B produced by Clostridium difficile is a common procedure in algorithms designed for its detection. Moreover, the absence of a unique test capable of providing reliable results at low cost motivates a great discussion about which algorithm is the best. Thus, several studies have evaluated the performance of these enzyme immunoassays. However, all fail to provide sufficient explanations for the different behaviours observed in different studies that evaluate the same index test against a common reference method. Our main goal was to find out which factors affect the sensitivity of these assays, since the specificity is very close to 1. In this research, we verified that sensitivity increases with the prevalence rate and with the proportion of reported cases of onset diarrhea. Therefore, its use is advisable for high prevalence rates (e.g. in an epidemic setting). As far as reference methods are concerned, nucleic acid amplification tests can be used as a reference method, with a performance similar to the well-accepted toxigenic culture. The method chosen for toxigenicity screening in a toxigenic culture also seems to affect the evaluation performance of tests and should be better studied in the future.
Subject(s)
Bacterial Toxins/analysis , Clostridioides difficile/immunology , Clostridium Infections/diagnosis , Enterotoxins/analysis , Immunoenzyme Techniques/methods , Algorithms , Bacterial Proteins , Diagnostic Tests, Routine , Diarrhea , Feces/chemistry , Humans , Nucleic Acid Amplification Techniques/methods , Sensitivity and SpecificityABSTRACT
Currently, testing for immunoglobulin E (IgE) sensitization is the cornerstone of diagnostic evaluation in suspected allergic conditions. This review provides a thorough and updated critical appraisal of the most frequently used diagnostic tests, both in vivo and in vitro. It discusses skin tests, challenges, and serological and cellular in vitro tests, and provides an overview of indications, advantages and disadvantages of each in conditions such as respiratory, food, venom, drug, and occupational allergy. Skin prick testing remains the first line approach in most instances; the added value of serum specific IgE to whole allergen extracts or components, as well as the role of basophil activation tests, is evaluated. Unproven, non-validated, diagnostic tests are also discussed. Throughout the review, the reader must bear in mind the relevance of differentiating between sensitization and allergy; the latter entails not only allergic sensitization, but also clinically relevant symptoms triggered by the culprit allergen.
ABSTRACT
BACKGROUND: Rotavirus is considered worldwide as one of the most important viral gastrointestinal infections, resulting in potentially life-threatening diarrhoea and death in children under the age of 5 years. Rotavirus can survive and remain infectious for long periods outside of the human body and can be easily transmitted via environmental surfaces. METHOD: Stool specimens that had been collected and stored since 2010/2011 at 2°C - 8°C instead of -20°C or -80°C were analysed to determine the viability of rotavirus in these specimens after 6 years of improper storage. The specimens were analysed using simple enzyme immunoassay (EIA) methods from two different suppliers at different times throughout the period (2012-2017). RESULTS: The analysis showed similar detection results for the two EIA kits. CONCLUSION: The rotavirus can be detected after several years of incorrect storage with EIA kits.
ABSTRACT
Where dengue virus infections are endemic, acute febrile illness is often managed as dengue fever (DF) without diagnostic testing. In a prospective study of 140 patients with clinical features of DF, 3 (2.1%) had acute HIV infection (AHI). We recommend testing for AHI in dengue-like febrile illness.
ABSTRACT
Dried blood spots (DBSs) could be an alternative to serum for hepatitis B virus (HBV) and hepatitis C virus (HCV) diagnosis. This study aims to evaluate two enzyme immunoassays (EIAs) for HBsAg and anti-HCV detection using DBS. Serum was tested using commercial EIA. DBS was tested using optimized EIA developed for serum and commercial EIA developed for DBS (Imunoscreen). Concordances between DBS and serum samples for both markers and EIAs were higher than 97%. Both EIAs demonstrated good performance for HBsAg and anti-HCV detection using DBS, and these methods could be used unchangeably increasing the access for HBV and HCV diagnosis.
Subject(s)
Dried Blood Spot Testing , Hepacivirus/isolation & purification , Hepatitis B virus/isolation & purification , Immunoenzyme Techniques/methods , HumansABSTRACT
Measurement of Aspergillus-specific IgG is central to the diagnosis of chronic pulmonary aspergillosis (CPA), but manufacturers' guidance on test interpretation is based on unpublished data. We performed the first receiver operating characteristic (ROC) area under the curve (AUC) analysis to identify optimal cut-offs for this test in relation to European controls. Aspergillus-specific IgG levels were measured in sera from British adults with CPA and European healthy controls by ImmunoCAP, Immulite, Serion and Bio-Rad assays. ROC AUC analysis was performed to identify optimal cut-offs. ROC AUC results were; Bio-Rad 0.955, Immulite 0.948, ImmunoCAP 0.956 and Serion 0.944. Optimal diagnostic cut-offs were 1.5 AU/mL for Bio-Rad (93% sensitive, 98% specific), 25 mg/L for Immulite (93% sensitive, 99% specific), 50 mg/L for ImmunoCAP (84% sensitive, 96% specific) and 50 U/mL for Serion (84% sensitive, 91% specific). These cut-offs differ from manufacturers' guidance and from those previously calculated in relation to Ugandan controls.
Subject(s)
Antibodies, Fungal/blood , Aspergillus/immunology , Immunoglobulin G/blood , Pulmonary Aspergillosis/diagnosis , Adult , Aged , Aged, 80 and over , Area Under Curve , Aspergillus/isolation & purification , Chronic Disease , Cohort Studies , Female , Humans , Immunoenzyme Techniques , Male , Middle Aged , Pulmonary Aspergillosis/microbiology , ROC Curve , Species Specificity , Young AdultABSTRACT
Shiga toxin-producing Escherichia coli (STEC) are important enteric pathogens responsible for sporadic cases and outbreaks of gastroenteritis. E.coli O157:H7/NM (STEC O157) are the most commonly known STEC serotypes but it is now increasingly apparent that non-O157 STEC serotypes have been underreported in the past because they were not part of routine screening in many front-line laboratories. The Canadian Public Health Laboratory Network (CPHLN) has identified the need for improved detection and surveillance of non-O157 STEC and has developed the following recommendations to assist in the decision-making process for clinical and reference microbiology laboratories. These recommendations should be followed to the best of a laboratory's abilities based on the availability of technology and resources. The CPHLN recommends that when screening for the agents of bacterial gastroenteritis from a stool sample, front-line laboratories use either a chromogenic agar culture or a culture-independent diagnostic test (CIDT). CIDT options include nucleic acid amplification tests (NAATs) to detect Shiga toxin genes or enzyme immunoassays (EIAs) to detect Shiga toxins. If either CIDT method is positive for possible STEC, laboratories must have a mechanism to culture and isolate STEC in order to support both provincial and national surveillance as well as outbreak investigations and response. These CPHLN recommendations should result in improved detection of STEC in patients presenting with diarrhea, especially when due to the non-O157 serotypes. These measures should enhance the overall quality of healthcare and food safety, and provide better protection of the public via improved surveillance and outbreak detection and response.
ABSTRACT
BACKGROUND: Chronic Hepatitis B Virus (HBV) infection is characterised by the persistence of hepatitis B surface antigen (HBsAg). Expanding HBV diagnosis and treatment programmes into low resource settings will require high quality but inexpensive rapid diagnostic tests (RDTs) in addition to laboratory-based enzyme immunoassays (EIAs) to detect HBsAg. The purpose of this review is to assess the clinical accuracy of available diagnostic tests to detect HBsAg to inform recommendations on testing strategies in 2017 WHO hepatitis testing guidelines. METHODS: The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines using 9 databases. Two reviewers independently extracted data according to a pre-specified plan and evaluated study quality. Meta-analysis was performed. HBsAg diagnostic accuracy of rapid diagnostic tests (RDTs) was compared to enzyme immunoassay (EIA) and nucleic-acid test (NAT) reference standards. Subanalyses were performed to determine accuracy among brands, HIV-status and specimen type. RESULTS: Of the 40 studies that met the inclusion criteria, 33 compared RDTs and/or EIAs against EIAs and 7 against NATs as reference standards. Thirty studies assessed diagnostic accuracy of 33 brands of RDTs in 23,716 individuals from 23 countries using EIA as the reference standard. The pooled sensitivity and specificity were 90.0% (95% CI: 89.1, 90.8) and 99.5% (95% CI: 99.4, 99.5) respectively, but accuracy varied widely among brands. Accuracy did not differ significantly whether serum, plasma, venous or capillary whole blood was used. Pooled sensitivity of RDTs in 5 studies of HIV-positive persons was lower at 72.3% (95% CI: 67.9, 76.4) compared to that in HIV-negative persons, but specificity remained high. Five studies evaluated 8 EIAs against a chemiluminescence immunoassay reference standard with a pooled sensitivity and specificity of 88.9% (95% CI: 87.0, 90.6) and 98.4% (95% CI: 97.8, 98.8), respectively. Accuracy of both RDTs and EIAs using a NAT reference were generally lower, especially amongst HIV-positive cohorts. CONCLUSIONS: HBsAg RDTs have good sensitivity and excellent specificity compared to laboratory immunoassays as a reference standard. Sensitivity of HBsAg RDTs may be lower in HIV infected individuals.
Subject(s)
Hepatitis B Surface Antigens/blood , Hepatitis B/diagnosis , Immunoenzyme Techniques/methods , Databases, Factual , Humans , Immunoenzyme Techniques/standards , Quality Control , Reagent Kits, Diagnostic , Sensitivity and SpecificityABSTRACT
BACKGROUND: Clinical and laboratory diagnosis of Active Tuberculosis (ATB) and latent Mycobacterium Tuberculosis (M. tuberculosis) infections (LTBI) among people living with HIV/AIDS (PLWHA) presents formidable challenges. In the past, WHO issued an advisory against the use of existing TB sero-diagnostics. Emerging evidence, however, points to a precision of TB sero-diagnostics based on secretory rather than structural M. tuberculosis antigens. We hypothesized that secretory levels of M. tuberculosis thymidylate kinase (TMKmt) can Designate ATBI from LTBI and no TB (NTB). Here, we report in-house validation studies of levels of TMKmt antigen (Ag) and host specific TMKmt antibody (Ab) amongst HIV +ve and HIV -ve participants. METHODS AND RESULTS: Direct TMKmt Ag and host specific IgG Ab detection EIAs were conducted on broadly consented, stored serum (N=281[Ag] vs. 214 [Ab] respective) samples stratified as either HIV +ve or HIV-ve ATB relative to LTBI and No TB. On one hand, UG-peptide 1 and its PAb-based EIAs accurately diagnosed ATB relative to LTBI and NTB among HIV +ve subjects {irrespectively: (a) Ag detection ATB=OD>0.490; 95% CI: 0.7446 to 0.8715 vs. LTBI=OD<0.490; 95% CI 0.4325 to 0.4829 vs. NTB=OD<0.26; 95% CI 0.1675 to 0.2567 and (b) TMKmt specific IgG detection ATB=OD>1.00; 95% CI 1.170 to 1.528 [HIV +ve] and 2.044 to 2.978 [HIV -ve] respectively vs. LTBI=OD<1.00; 95% CI 0.2690 to 0.6396 vs. NTB=OD<; 95% CI 0.1527 to 0.8751}. HIV -ve ATB presented with Ag levels greater than NTB and less than LTBI (i.e. ATB -ve=<0.490 ODs>0.26), but displayed better ant-TMKmt IgG responses (OD>2.00; 95% CI 2.044 to 2.978) relative to HIV +ve ATB (OD<1.600; 95% CI 1.170 to 1.528); suggesting a better control of M. tuberculosis-septicemia. On the other hand, UG-peptide 2 and its PAb-based EIAs did not demonstrate ATB diagnostic potential regardless of HIV sero-status, except towards designating NTB. CONCLUSIONS: TMKmt Ab and Ag detecting EIAs based on UG-peptide 1 and its derivative PAb can accurately demarcate ATB from LTBI and NTB among HIV +ve subjects.
ABSTRACT
Non-invasive measurement of cortisol in saliva is of prime importance as it represents a bioavailable neuroendocrine marker for stress. Therefore, in this study, we developed an enzyme immune assay that was suitable for salivary cortisol measurements. For that purpose, rabbit polyclonal antibody was raised against cortisol-3-CMO:BSA conjugate. The test was based on competition of liquid phase cortisol with conjugated cortisol on the solid phase. Primary antibody was used to bind available sites on the conjugate, which was proportional to numbers of cortisol in liquid phase. Biotinylated secondary anti-rabbit antibody was used to detect primary antibodies by addition of streptavidin peroxidase and substrate, respectively. Color formation was stopped and yellow color was read by a plate-reader spectrophotometer. Additionally, validated test was used to met all validation criteria including. Test developed was used to establish cortisol awakening response (CAR) in saliva samples collected in the morning after awakening (0, 15, 30, and 60th min) from women (n = 4) and men (n = 4) at 8 or 4 different days, respectively. Diurnal cortisol levels were assessed (n = 8) at after awaking 60 min at morning, 12:00, 19:00, and 22:00 hr. In conclusion, an enzyme immunoassay test was successfully produced, validated and used for cortisol measurement in saliva samples.
Subject(s)
Enzyme-Linked Immunosorbent Assay/methods , Enzyme-Linked Immunosorbent Assay/standards , Hydrocortisone/analysis , Saliva/chemistry , Adolescent , Adult , Healthy Volunteers , Humans , Young AdultABSTRACT
Clostridium difficile is a major cause of nosocomial antibiotic-associated infectious diarrhea and pseudomembranous colitis. Detection of C. difficile by anaerobic bacterial culture and/or cytotoxicity assays has been largely replaced by rapid enzyme immunoassays (EIA). However, due to the lack of sensitivity of stool EIA, we developed a multiplex real-time PCR assay targeting the C. difficile toxin genes tcdB. stool samples from hospitalized pediatric patients suspected of having C. difficile-associated disease were prospectively collected. Three testing modalities were evaluated, including enriched culture, cepheid Xpert and real-time Pcr (tcdB) on stool samples performed with tcdB gene-specific primers and hydrolysis probes. A total of 150 de-identified clinical specimen were analyzed. The sensitivities of stool real-time Pcr were 95% against cepheid Xpert C. difficile and 93% against enriched culture respectively, with a specificity of 97% and 94%. The lower limit of detection of the stool real-time PCR was 0.5 cFU/ml of per reaction for tcdB. Direct detection of C. difficile toxin genes in stool samples by real-time Pcr showed performance comparable to enriched culture. Real-time PCR of DNA from stool samples is a rapid and cost-effective diagnostic modality for patients that should facilitate appropriate patient management.
ABSTRACT
BACKGROUND/AIM: Human parvovirus B19 is a pathogen that affects different parts of the body. We planned this study because of the lack of data on B19 seroprevalence based on different body-system diseases. MATERIALS AND METHODS: The prevalence of parvovirus B19 antibodies was investigated retrospectively in 1239 patients by review of medical records from 2009-2012, according to their diseases classified under general titles in compliance with the International Classification of Diseases (ICD-10). Parvovirus B19-specific antibodies were detected by quantitative enzyme immunoassays. RESULTS: The positivity rate was 27.8% for only IgG, 8.5% for only IgM, and 2.6% for both IgG and IgM. The highest positivity for IgG alone was found in musculoskeletal system and connective tissue diseases (55.9%), while the highest positivity for IgM was found in neoplasms (16.4%). The highest positivity for IgG was seen in rheumatoid arthritis (72.2%) and pregnancy (52.6%), and the highest positivity for total IgM was found in upper respiratory tract disease (21.0%) and hepatic failure (17.1%). CONCLUSION: Parvovirus B19 seroprevalence was relatively low in northeastern Anatolia compared to most serological studies conducted in other regions. We think that this study has provided the first wide-ranging information on the seroprevalence of B19 in diseases and disorders of the major human body systems.
Subject(s)
Parvoviridae Infections , Antibodies, Viral , DNA, Viral , Female , Human Body , Humans , Immunoglobulin G , Immunoglobulin M , Parvovirus B19, Human , Pregnancy , Prevalence , Seroepidemiologic StudiesABSTRACT
Detection of HIV infection provides an opportunity for transmission reduction and lifesaving treatment strategies. This study examined patients' willingness to take a routine, rapid oral HIV test if offered at a dental school clinic. For fifteen days in 2011, an anonymous survey containing demographic information and willingness to be tested questions was offered to all patients awaiting treatment. A total of 383 of 443 people approached, answered the questionnaire (40.2% Hispanic, 27.2% Caucasian, and 19.3% African American) with 58.8% indicating that they had been previously tested for HIV (as compared to the California mean of 39.2%). Patients were highly likely to participate (84.0% of Hispanics, 63.6% of Caucasians, 80.0% of African Americans and 66.7% of Asians) in a free HIV rapid test when given the opportunity. Of respondents never tested before, 62.6% reported a willingness to be tested in this study. HIV screening in a dental clinic during routine visits may allow new undiagnosed cases to be detected with subsequent referral into medical treatment.
Subject(s)
Dental Clinics , HIV Infections/diagnosis , Patient Acceptance of Health Care , Adolescent , Adult , Aged , Aged, 80 and over , Female , HIV Infections/ethnology , Humans , Los Angeles , Male , Middle Aged , Patient Acceptance of Health Care/ethnology , Surveys and Questionnaires , Urban PopulationABSTRACT
Using the role of p-iodophenol in enzyme assay, enhanced 1,1'-oxalyldiimidazole chemiluminescent enzyme immunoassays (ODI-CLEIAs) were developed to consecutively quantify trace levels of triple tumor markers, such as alpha fetoprotein (AFP), carcinoembryonic antigen (CEA), and prostate specific antigen (PSA) in a sample. Due to the high sensitivity of enhanced ODI-CLEIAs, it was possible to fix the incubation times (1) to capture a tumor marker with two antibodies, which are primary antibody immobilized on the surface of polystyrene strip-well and detection antibody-conjugated horseradish peroxidase (HRP), and (2) to form resorufin with the addition of substrates (e.g., Amplex Red, H2O2) in order to quantify triple markers in human serum. Enhanced ODI-CLEIAs capable of consecutively and rapidly quantifying triple markers with the same incubation time were more sensitive than conventional enzyme-linked immunosorbent assay (ELISA) capable of separately and slowly quantifying them with different incubation times. In addition, accuracy, precision, and recovery of enhanced ODI CLEIAs in the presence of p-iodophenol were acceptable within statistical error range.
Subject(s)
Biomarkers, Tumor/analysis , Immunoenzyme Techniques/methods , Iodobenzenes/chemistry , Luminescence , Calibration , Carcinoembryonic Antigen/blood , Horseradish Peroxidase/chemistry , Humans , Hydrogen Peroxide/chemistry , Luminescent Measurements , Oxazines/chemistry , Prostate-Specific Antigen/blood , Reproducibility of Results , alpha-Fetoproteins/chemistryABSTRACT
Entomopathogenic Bacillus thuringiensis is closely related to Bacillus cereus, a human pathogen known to cause emesis and diarrhea. Standard detection methods do not distinguish these bacilli. Hemolysin BL (hbl) and non-hemolytic enterotoxin (nhe) genes that encode, respectively, HBL and NHE enterotoxins, are known to be harbored in both bacterial species, suggesting that differentiation of these bacilli is clinically and epidemiologically relevant. In this study the reliability of quantitative reverse transcription real-time PCR (qRT-PCR) and enzyme immunoassays (EIAs) in detecting hbl and nhe transcripts and corresponding toxins in environmental B. thuringiensis isolates was assessed. At least one enterotoxin gene was present in each isolate, and nhe or hbl genes were found in 85% and 55% of the strains, respectively. Based on statistical analyses, both BCET-RPLA and Duopath detected HBL at similar levels, and TECRA and Duopath can be used interchangeably for the detection of NHE, although TECRA has significantly lower sensitivity than Duopath. Thus, as potential enterotoxic B. thuringiensis strains occur in the natural environment, and EIA results may not correspond with the presence of enterotoxin genes and their expression, we suggest that reliable interpretation will be significantly enhanced by including qRT-PCR to support inferences based on EIAs.
Subject(s)
Bacillus thuringiensis/genetics , Bacillus thuringiensis/isolation & purification , Enterotoxins/genetics , Immunoassay/methods , Real-Time Polymerase Chain Reaction/methods , Reverse Transcriptase Polymerase Chain Reaction/methods , Bacterial Proteins/genetics , DNA, Bacterial/genetics , Hemolysin Proteins/genetics , Reproducibility of ResultsABSTRACT
We evaluated the new C. DIFF QUIK CHEK COMPLETE (CD COMPLETE; TechLab, USA), which is a rapid membrane enzyme immunoassay that uses a combination of glutamate dehydrogenase (GDH) antigen and toxin A and B detection. A total of 608 consecutive loose stool specimens collected from the patients with suspected Clostridium difficile infection (CDI) from August to December 2012 were subjected to the CD COMPLETE and VIDAS Clostridium difficile A & B (VIDAS CDAB; bioMérieux, France). Their performances were compared with a toxigenic culture as a reference. Stool specimens that were culture-negative and CD COMPLETE- or VIDAS CDAB-positive were analyzed by using an enrichment procedure. In comparison to the toxigenic cultures, sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV) were 63.6%, 98.0%, 76.1%, and 96.4%, respectively, for the CD COMPLETE-toxin and 75.5%, 97.4%, 72.5%, and 97.8%, respectively, for the VIDAS CDAB. In comparison to the enriched C. difficile cultures, the sensitivity, specificity, PPV, and NPV for the CD COMPLETE-GDH were 91.0%, 92.4%, 70.5%, and 98.1%, respectively. The CD COMPLETE is a reliable method for the diagnosis of CDI and provides greater sensitivity than toxin enzyme immunoassay alone. Furthermore, the CD COMPLETE-GDH has advantages over direct culture in detecting C. difficile.