ImmunoCard STAT Research Articles

Molecular, Microscopic, and Immunochromatographic Detection of Enteroparasitic Infections in Hemodialysis Patients and Related Risk Factors.

Intestinal parasitic infection (IPI) is one of the important causes of morbidity and mortality in patients with chronic renal failure (CRF). Patients with CRF are more prone to infections due to acquired immunodeficiency caused by uremia. This study aims at determining the prevalence of parasitic intestinal infections in hemodialysis (HD) patients in Makkah, Saudi Arabia, and at comparing the techniques used for the detection of intestinal parasites. One hundred stool samples were collected from Saudi HD patients from two dialysis centers of two hospitals in Makkah City, and 50 samples were collected randomly from healthy individuals that served as control. The laboratory tests were carried out at King Fahd Medical Research Center, King Abdulaziz University, Jeddah. One stool sample was collected from each participant and examined with different techniques. The diagnosis was carried out using the direct wet smear with normal saline and native-Lugol's, Ritchie technique, rapid diagnostic test (ImmunoCard STAT! CGE), and molecular techniques (real-time polymerase chain reaction). The relation between age, gender, weight, and height to calculate body mass index, level of education, time of the HD, lifestyle, residence status, several gastrointestinal symptoms, blood pressure, diabetes, irritable bowel disease, and other factors was studied. Intestinal parasites were found in 38% of the HD patients and 36% of the control group. The most encountered intestinal parasites in the HD patients and control group were Blastocystis hominis (31%) and (34%), Entamoeba histolytica (3%) and (2%) respectively, Endolimax nana (4%) in the HD group, Giardia lamblia (4%) in the control group, and no positive results for Cryptosporidium or helminths in both groups. The IPIs should be suspected in all cases of immunodeficient patients, and stool samples should be ordered as routine with other tests in interval times and examined using special techniques. The physicians should be aware of the similarity between HD and intestinal parasitosis symptoms to perform diagnostic tests and determine the suitable treatment.

Detection of Giardia lamblia by Microscopic Examination, Rapid Chromatographic Immunoassay Test, and Molecular Technique.

BackgroundGiardia lamblia is a pathogenic intestinal flagellate transmitted by the ingestion of contaminated water or food with the cyst stage of the parasite. Giardiasis can cause severe acute diarrhea and malabsorption or may persist as a chronic infection. Effective treatment and control measures depend on proper laboratory diagnosis using diagnostic methods with high sensitivity and specificity.ObjectiveTo compare the sensitivity and specificity of direct smear, Ritchie sedimentation technique, two brands of rapid chromatographic immunoassay test, and real-time polymerase chain reaction (PCR) for the detection of G. lamblia in clinical human fecal samples.Materials and methodsUnpreserved 100 stool specimens were collected in clean plastic containers and labeled with the patient’s information and examined through light microscopy, immunochromatographic test (ICTs), and real-time PCR.ResultsOut of 100 fresh stool samples obtained from workers analyzed, real-time PCR targeting the SSU rRNA gene was able to detect Giardia deoxyribonucleic acid (DNA) in (42) samples followed by ImmunoCard STAT! (31) samples (Meridian Bioscience, Germany), direct smear (23) samples, CerTest (19) samples (Biotec, Zaragoza, Spain), and Ritchie technique (17) samples. Real-time PCR was the most sensitive for the diagnosis of G. lamblia in comparison to the other techniques.ConclusionsAll the techniques investigated were sensitive for the detection of G. lamblia in stool samples. Further studies are recommended using multiplex real-time PCR assay in order to increase the possibility of the presence or absence of the infection.

Prospective, study comparing the accuracy of two different stool antigen tests (Premier Platinum HpSA and novel ImmunoCard STAT! rapid test) for the diagnosis of Helicobacter pylori infection

At present only monoclonal EIA (enzyme-immunoassay) stool antigen-tests have obtained optimal accuracy in the diagnosis of Helicobacter pylori. Our aim was to evaluate the accuracy of two stool antigen-tests, the validated Premier Platinum HpSA PLUS (EIA test) and the newly available ImmunoCard STAT! HpSA HD (rapid test) for the initial diagnosis and the confirmation of eradication of H. pylori infection. Patients with indication of H. pylori diagnosis, or confirmation after treatment were included. Data were coded to protect personal data and ensure blindness between tests. Accuracy was considered as coincident diagnosis with the gold standard (13C-urea breath test, UBT). The EIA was used as a bench standard. All stool tests were performed in duplicate. 264 patients completed the protocol (100 naïve, 164 post-eradication). Average age was 52 years, 61% women, 11% ulcer. Positive diagnoses by UBT were 41% for naïve and 17% for post-eradication. Overall ImmunoCard and EIA accuracies were respectively 91% (95%C.I. = 88–94%) and 89% (86–93%), sensitivities 72% (67–78%) and 72% (67–78%), and specificities 98% (96–100%), and 95% (92–97%). Concordance between ImmunoCard and EIA was 95% (93–98%). Our results indicate that the newly available ImmunoCard rapid stool antigen-test achieves 90% accuracy, with high specificity but suboptimal sensitivity. The ImmunoCard attained equivalent accuracies as the EIA bench standard, with 95% concordance. En la actualidad, únicamente los métodos de detección de antígenos en heces monoclonales basados en enzimoinmunoanálisis (ELISA) han obtenido una adecuada precisión para el diagnóstico de la infección por Helicobacter pylori. Nuestro objetivo fue evaluar la exactitud (sensibilidad y especificidad) de 2 métodos de antígenos en las heces, el previamente validado Premier Platinum HpSA® PLUS (ELISA) y el nuevo ImmunoCard® STAT! HpSA® HD (test rápido), para el diagnóstico inicial y la confirmación de la erradicación de la infección por H. pylori. Se incluyeron pacientes en los que estaba indicado el diagnóstico inicial de la infección por H. pylori o su confirmación tras el tratamiento. Los datos fueron codificados y los evaluadores de ambos test fueron ciegos para los resultados de las pruebas diagnósticas. El resultado principal fue la coincidencia con el resultado del patrón oro (prueba del aliento con 13C-urea). Los test en heces se realizaron por duplicado. Doscientos sesenta y cuatro pacientes completaron el protocolo (100 naïve, 164 posterradicación). La edad media fue de 52 años, el 61% fueron mujeres y el 11% tenían úlcera péptica. La prueba del aliento fue positiva en el 41% de los pacientes naïve y en el 17% posterradicación. La exactitud global del método rápido y del ELISA fue, respectivamente, 91% (IC 95%: 88-94%) y 89% (86-93%), la sensibilidad 72% (67-78%) y 72% (67-78%), y la especificidad 98% (96-100%) y 95% (92-97%). La concordancia entre el método ImmunoCard® y ELISA fue del 95% (93-98%). El nuevo método rápido de antígenos en heces (ImmunoCard® STAT! HpSA® HD) tiene una exactitud diagnóstica del 90%, con una elevada especificidad, pero una sensibilidad insuficiente. El método ImmunoCard® tiene una exactitud equivalente al método ELISA estándar, con una concordancia del 95%.

Accuracy of rapid Helicobacter pylori antigen tests for the surveillance of the updated prevalence of H. pylori in Taiwan

The updated prevalence of Helicobacter pylori (H. pylori) is lacking in Taiwan. We aimed to assess the accuracy of Vstrip® H. pylori Stool Antigen Rapid Test (Vstrip®HpSA) in the detection and surveillance of the updated prevalence of H. pylori in Taiwan. A total of 347 adult subjects including 152 volunteers and 195 symptomatic patients were recruited. Stool samples were collected for detection of H. pylori using Vstrip® HpSA, ImmunoCard STAT!® HpSA and Premier Platinum HpSA® PLUS. All subjects who have completed the stool sample collections were included in the ITT analysis. The sensitivity, specificity, and accuracy of Vstrip® HpSA were calculated compared to gold standard test with 13C-Urea breath test. The un-adjusted prevalence of H. pylori infection was 22.5% (95% CI: 18.3-27%) in 2018. The age-standardized prevalence of H. pylori was 21.8% in asymptomatic adults in Taiwan. The sensitivity, specificity, and accuracy of the Vstrip® HpSA, and ImmunoCard STAT!® HpSA tests were 91% (95% CI: 82-96%) versus 76.9% (95% CI: 66-86%), 97% (95% CI: 94.1-98.6%) versus 97% (95% CI: 94.1-98.6%), and 95.7% (95% CI: 92-97%) versus 92.5% (95% CI: 89-95%), respectively. The age-standardized prevalence of H. pylori infection in Taiwan was 21.8% in asymptomatic adults in 2018. The Vstrip® HpSA had equivalent performance as the ImmunoCard STAT!® HpSA, and can be used in future mass screening of H. pylori infection for gastric cancer prevention.

Prospective, study comparing the accuracy of two different stool antigen tests (Premier Platinum HpSA and novel ImmunoCard STAT! rapid test) for the diagnosis of Helicobacter pylori infection

BackgroundAt present only monoclonal EIA (enzyme-immunoassay) stool antigen-tests have obtained optimal accuracy in the diagnosis of Helicobacter pylori. Our aim was to evaluate the accuracy of two stool antigen-tests, the validated Premier Platinum HpSA PLUS (EIA test) and the newly available ImmunoCard STAT! HpSA HD (rapid test) for the initial diagnosis and the confirmation of eradication of H. pylori infection. Patients and methodsPatients with indication of H. pylori diagnosis, or confirmation after treatment were included. Data were coded to protect personal data and ensure blindness between tests. Accuracy was considered as coincident diagnosis with the gold standard (13C-urea breath test, UBT). The EIA was used as a bench standard. All stool tests were performed in duplicate. Results264 patients completed the protocol (100 naïve, 164 post-eradication). Average age was 52 years, 61% women, 11% ulcer. Positive diagnoses by UBT were 41% for naïve and 17% for post-eradication. Overall ImmunoCard and EIA accuracies were respectively 91% (95%C.I.=88–94%) and 89% (86–93%), sensitivities 72% (67–78%) and 72% (67–78%), and specificities 98% (96–100%), and 95% (92–97%). Concordance between ImmunoCard and EIA was 95% (93–98%). DiscussionOur results indicate that the newly available ImmunoCard rapid stool antigen-test achieves 90% accuracy, with high specificity but suboptimal sensitivity. The ImmunoCard attained equivalent accuracies as the EIA bench standard, with 95% concordance.

2141. Potential for Harm From Rapid Campylobacter Antigen Test: Quality Improvement Process Reveals 84% False-Positive STAT! Campy Stool Antigen Results

BackgroundThe Immunocard STAT! Campy is known to have a poor correlation with Campylobacter culture, and bloody stools are thought to be the most common cause of false-positive tests. A CDC investigation of 11 cases of Campylobacter in premature infants with non-bloody stools between March and April, 2018 at the Children’s Hospital of Illinois identified a pseudo-outbreak secondary to false-positive stool antigen tests.MethodsBeginning May 1, 2018, Immunocard STAT! Campy (Meridian BioScience) positive stools from 14-hospitals in the OSF network were sent to the OSF System lab for confirmation prior to resulting in the medical record (MR). Stool was placed into Cary Blair media and a STAT! Campy stool antigen test was repeated in the OSF System Lab. BioFire GI Panel (GIP) PCR was performed on STAT! Campy positive stools, and results reported in the MR.ResultsBetween May 1, 2018 and April 30, 2019, 3,639 stools were submitted for culture. 372 tested positive by the STAT! Campy rapid antigen test and were referred for confirmation. Repeat rapid antigen tests were negative for 56% (208/372) of stools and were finalled in the MR as negative without GIP testing. GIP PCR was performed on 164 samples from 163 patients (mean age = 18). 43% (71/164) of GIP were completely negative; 16% (27/164) positive STAT! Campy antigens were confirmed by the GIP (84% were false positive). Pathogens detected by the GIP included: 30 viral infections (50% Norovirus), 27 cases of C. difficile, and 19 pathogenic E. coli (Table 1). Multiple pathogens were detected in 15% (25/163) patients (1 patient was positive for 4 pathogens). One case of Salmonella was not detected by GIP. One patient tested negative by the GIP but remained symptomatic and C. difficile was detected on repeat testing 10 days later.Conclusion C. difficile and Norovirus were the most common pathogens detected in stools that yielded false positive STAT! Campy results. These findings have important patient care and infection control implications. Currently neither FDA nor CDC requires Campylobacter culture (or other laboratory methods) of confirmation of positive Campylobacter stool antigen tests. Missed and incorrect diagnoses represent a significant risk of harm for patients (particularly C. difficile or Shiga toxin-infected patients, Table 1), and outbreaks in institutional settings. Disclosures All authors: No reported disclosures.

Prevalence of Clostridium difficile infections among Kenyan children with diarrhea

BackgroundDiarrhea causes significant morbidity and mortality among children worldwide. Regions most affected by diarrhea include Sub-Saharan Africa and Southeast Asia, where antibiotics are in common use and can make children more vulnerable to Clostridium difficile and pathogens that are not affected by these drugs. Indeed, C. difficile is a major diarrhea-associated pathogen and poses a significant threat to vulnerable and immunocompromised populations. Yet, little is known about the role and epidemiology of C. difficile in diarrhea-associated illness among young children. As a result, C. difficile is often neglected in regions such as Sub-Saharan Africa that are most impacted by childhood diarrhea. The purpose of this study was to establish the frequency of C. difficile in young children (<5 years) with diarrhea. MethodsChildren presenting with diarrhea at a national hospital in Kenya from 2015 to 2018 were enrolled consecutively. Following informed consent by a parent or legal guardian, stool samples were obtained from the children and demographic data were collected. The stools were examined for the presence of four common pathogens known to cause diarrhea: C. difficile, rotavirus, Cryptosporidium parvum, and Giardia lamblia. C. difficile was verified by toxigenic culture and PCR. The presence of C. parvum and/or G. lamblia was determined using the ImmunoCard STAT! Crypto/Giardia Rapid assay. Rotavirus was detected by ELISA. ResultsThe study population comprised 157 children; 62.4% were male and 37.6% were female and their average age was 12.4 months. Of the 157 stool specimens investigated, 37.6% were positive for C. difficile, 33.8% for rotavirus, 5.1% for Cryptosporidium, and 5.1% for Giardia. PCR analysis identified at least one of the C. difficile-specific - genes (tcdA, tcdB, or tcdC). Further, 57.6% of the stools had C. difficile colonies bearing a frame-shift deletion in the tcdC gene, a mutation associated with increased toxin production. The frequency of C. difficile was 32.6% in children ≤12 months old and increased to 46.6% in children 12–24 months old. ConclusionsIn Kenyan children presenting with diarrhea, C. difficile is more prevalent than rotavirus or Cryptosporidium, two leading causes of childhood diarrhea. These findings underscore the need to better understand the role of C. difficile in children with diarrhea, especially in areas with antibiotic overuse. Understanding C. difficile epidemiology and its relationship to co-infecting pathogens among African children with diarrhea will help in devising ways of reducing diarrhea-associated illness.

Evaluation of the Field Performance of ImmunoCard STAT!® Rapid Diagnostic Test for Rotavirus in Dadaab Refugee Camp and at the Kenya-Somalia Border.

Rotavirus commonly causes diarrhea in children, leading to hospitalization and even death. Rapid diagnostic tests are feasible alternatives for determining rotavirus outbreaks in refugee camps that have inadequate laboratory capacity. We evaluated the field performance of ImmunoCard STAT!® Rotavirus (ICS-RV) in Dadaab Refugee Camp and at the Kenya–Somalia border. From May to December 2014, we prospectively enrolled children aged < 5 years hospitalized with acute diarrhea, defined as ≥ 3 episodes of loose stool in 24 hours for < 7 days. Stool samples were collected and tested by trained surveillance clerks using ICS-RV per manufacturer's instructions. The field performance characteristics of ICS-RV were evaluated against the gold standard test, Premier™ Rotaclone® enzyme immunoassay. The operational characteristics were evaluated using World Health Organization (WHO) ASSURED criteria to determine whether ICS-RV is appropriate as a point-of-care test by administering a standard questionnaire and observing surveillance clerks performing the test. We enrolled 213 patients with a median age of 10 months (range = 1–48); 58.2% were male. A total of 71 (33.3%) and 60 (28.2%) patients tested positive for rotavirus infection by immunoassay and ICS-RV, respectively. The sensitivity, specificity, and positive and negative predictive values of ICS-RV compared with the immunoassay were 83.1% (95% confidence interval [CI] = 72.3–91.0), 99.3% (95% CI = 96.1–100), 98.3% (95% CI = 91.1–100), and 92.1% (95% CI = 86.6–95.5), respectively. The ICS-RV fulfilled the WHO ASSURED criteria for point-of-care testing. ICS-RV is a field-ready point-of-care test with good field performance and operational characteristics. It can be useful in determining rotavirus outbreaks in resource-limited settings.

Community Laboratory Testing for Cryptosporidium: Multicenter Study Retesting Public Health Surveillance Stool Samples Positive for Cryptosporidium by Rapid Cartridge Assay with Direct Fluorescent Antibody Testing.

Cryptosporidium is a common cause of sporadic diarrheal disease and outbreaks in the United States. Increasingly, immunochromatography-based rapid cartridge assays (RCAs) are providing community laboratories with a quick cryptosporidiosis diagnostic method. In the current study, the Centers for Disease Control and Prevention (CDC), the Association of Public Health Laboratories (APHL), and four state health departments evaluated RCA-positive samples obtained during routine Cryptosporidium testing. All samples underwent “head to head” re-testing using both RCA and direct fluorescence assay (DFA). Community level results from three sites indicated that 54.4% (166/305) of Meridian ImmunoCard STAT! positives and 87.0% (67/77) of Remel Xpect positives were confirmed by DFA. When samples were retested by RCA at state laboratories and compared with DFA, 83.3% (155/186) of Meridian ImmunoCard STAT! positives and 95.2% (60/63) of Remel Xpect positives were confirmed. The percentage of confirmed community results varied by site: Minnesota, 39.0%; New York, 63.9%; and Wisconsin, 72.1%. The percentage of confirmed community results decreased with patient age; 12.5% of community positive tests could be confirmed by DFA for patients 60 years of age or older. The percentage of confirmed results did not differ significantly by sex, storage temperature, time between sample collection and testing, or season. Findings from this study demonstrate a lower confirmation rate of community RCA positives when compared to RCA positives identified at state laboratories. Elucidating the causes of decreased test performance in order to improve overall community laboratory performance of these tests is critical for understanding the epidemiology of cryptosporidiosis in the United States (US).

Detection of Cryptosporidium in stool samples of immunocompromised patients.

Introduction:Cryptosporidium species is the most common opportunistic enteric parasite encountered in the immunocompromised patients. Considering the need to diagnose them early relies mostly on rapid tests such as antigen detection by immunochromatographic test (ICT), ELISA, and microscopy. However, the sensitivity and specificity varies with different methods and different kits used. This study was conducted to determine the intestinal parasitic profile in immunocompromised patients and to assess the diagnostic accuracy of the ICT using ImmunoCard STAT kit in detecting Cryptosporidium spp.Materials and Methods:The patients in this study were divided into two groups: one group was immunocompromised patients (n = 73) and the other was nonimmunocompromised individuals (n = 73). Stool microscopy, ICT, and polymerase chain reaction (PCR) were carried out for all stool samples.Results:Totally, 4 (5.4%) of 73 patients of the study group were positive for Cryptosporidium. The species detected were Cryptosporidium parvum and Cryptosporidium hominis. PCR was taken as gold standard in the current study. PCR detected Cryptosporidium in four samples while ICT in two samples and microscopy in one sample.Conclusion:Cryptosporidium was found to be the most common enteric parasite in the immunocompromised patients studied, followed by Cystoisospora, Entamoeba histolytica, and Strongyloides stercoralis. Although the ICT is a rapid test, it was less sensitive and more expensive in comparison to the PCR; hence, its utility appears to be limited in our setting.

IS THE IMMUNOCROMATOGRAPHIC FECAL ANTIGEN TEST EFFECTIVE FOR PRIMARY DIAGNOSIS OF HELICOBACTER PYLORI INFECTION IN DYSPEPTIC PATIENTS?

The diagnosis of H. pylori infection can be performed by non-invasive and invasive methods.The identification through a fecal antigen test is a non-invasive, simple, and relatively inexpensive test. To determine the diagnostic performance of fecal antigen test in the identification of H. pylori infection. H. pylori antigens were identified in the stools of dyspeptic patients undergoing upper gastrointestinal endoscopy. For the identification of H. pylori antigen, we use ImmunoCard STAT! HpSA with immunochromatography technique. Histopathology plus urease test were the gold standard. We studied 163 patients, 51% male, mean age of 56.7± 8.5years. H. pylori infection was present in 49%. Fecal test presented: sensitivity 67.5% (CI95% 60.6-72.9); specificity 85.5% (CI95% 78.9-90.7); positive predictive value 81.8% (CI95% 73.4-88.4) and negative predictive value 73,2% (CI95% 67.5-77.6); Positive likelihood ratio was 4.7 (CI95% 2.9-7.9) and Negative Likelihood Ratio 0.4 (CI95% 0.3-0.5). The prevalence odds ratio for a positive test was 12.3 (CI95% 5.7-26.3).The index kappa between FAT and histology/urease test was 0.53 (CI95% 0.39-0.64). Immunochromatographic FAT is less expensive than the other methods and readily accepted by the patients but its diagnostic performance does not recommend its use in the primary diagnosis, when the patient may have an active infection.

Evaluation of the SHIGA TOXIN QUIK CHEK and ImmunoCard STAT! EHEC as screening tools for the detection of Shiga toxin in fecal specimens

In this study we evaluated the performance of the SHIGA TOXIN QUIK CHEK (Techlab®, Blacksburg, VA) and the ImmunoCard STAT! Enterohaemorrhagic E. coli (EHEC) (Meridian BioScience, Cincinnati, OH, USA) assays as methods for qualitatively detecting the presence of Shiga toxin in human fecal specimens. A multiplex PCR for the detection of stx1 and stx2 was used as the standard for comparison. The SHIGA TOXIN QUIK CHEK detected all known Shiga toxin subtypes with the exception of Stx2f, while the ImmunoCard STAT! EHEC was unable to identify four of the seven Stx2 subtypes, including Stx2b and Stx2d. When compared to multiplex PCR based on Shiga toxin gene presence alone both assays demonstrated 100% specificity, and gave sensitivity values of 50.0% and 41.2% respectively. Correlation between each assay and the multiplex PCR was calculated by the use of kappa, with both assays exhibiting a moderate level of agreement.

Diagnostic accuracy of three monoclonal stool tests in a large series of untreated Helicobacter pylori infected patients

ObjectivesImmunochromatographic tests need to be improved in order to enhance their reliability. Recently, several new kits have appeared on the market. The objective was to evaluate the diagnostic accuracy of three monoclonal rapid stool tests – the new Uni-Gold™ H.pylori Antigen (Trinity Biotech, Ireland), the RAPID Hp StAR (Oxoid Ltd., UK) and the ImmunoCard STAT! HpSA (Meridian Diagnostics, USA) – for detecting H. pylori infection prior to eradication treatment. Design and methodsDiagnostic accuracy (sensitivity and specificity) and reliability (concordance between observers) were evaluated in 250 untreated consecutive dyspeptic patients. The gold standard for diagnosing H. pylori infection was defined as the concordance of two or more of rapid urease test (RUT), histopathology and urease breath test (UBT) or positive culture in isolation. Readings of immunochromatographic tests were performed by two different observers. Sensitivity, specificity, positive and negative predictive values and 95% confidence intervals were calculated. Sensitivity and specificity were compared using the McNemar test. ResultsThe three tests showed a good correlation, with Kappa values>0.9. RAPID Hp StAR had a sensitivity of 91%–92% and a specificity ranging from 77% to 85%. Its sensitivity was higher than that of Uni-Gold™ H.pylori Antigen and ImmunoCard STAT! HpSA (p<0.01). Uni-Gold™ H.pylori Antigen kit showed a sensitivity of 83%, similar to ImmunoCard STAT! HpSA. Specificity of Uni-Gold™ H.pylori Antigen approached 90% (87–89%) and was superior to that of RAPID Hp StAR (p<0.01). ConclusionsUni-Gold™ H.pylori Antigen and ImmunoCard STAT! HpSA present similar levels of diagnostic accuracy. RAPID Hp StAR was the most sensitive but less reliable of the three immunochromatographic stool tests. None are as accurate and reliable as UBT, RUT and histology.

Tasa de reinfección por Helicobacter pylori en una cohorte de pacientes colombianos tratados exitosamente con seguimiento superior a 2 años

El Helicobacter pylori (H. pylori) infecta por lo menos a la mitad de la población mundial, aunque la prevalen- cia es más alta en países subdesarrollados. La tasa de reinfección es variable en las diferentes regiones y puede incluir recrudescencia de la infección o verdadera recurrencia. Hasta el momento hay pocos estudios en Colombia que hayan investigado la recurrencia de la infección y ninguno se ha realizado en Bogotá, Colombia. Objetivo: determinar la tasa de recurrencia de H. pylori en pacientes tratados eficazmente con 3 terapias triples diferentes. Materiales y métodos: estudio observacional analítico anidado en una cohorte de 180 pacientes a la que se le erradicó exitosamente H. pylori durante 2008-2009. La erradicación se verificó con test respiratorio con urea marcada y el tiempo promedio de seguimiento fue 43,7 meses (rango 31-56 meses). La recurrencia se investigó con la prueba de antígenos fecales monoclonales ImmunoCard STAT® HpSA (Meridian Bioscience Inc.). Resultados: se siguieron 86 pacientes y el porcentaje total de reinfección por H. pylori fue de 5,8% (5/86) y la tasa anual de reinfección fue de 1,59% (5/313,4 pacientes año x 100). El primer caso de reinfección se presentó a los 32 meses y los demás ocurrieron a los 37, 42, 44 y 56 meses de seguimiento. La tasa de reinfección calculada fue 1,8%/año después de 2 años de seguimiento. Conclusiones: la tasa de reinfección de H. pylori en Bogotá es baja e inferior a la previamente informada para otras regiones de Colombia.

Evaluation of immunochromatographic test kits for the detection of norovirus in faecal specimens

<h3>Background</h3> The early detection of norovirus plays a vital role in the reduction of transmission and control of nosocomial viral gastroenteritis. <h3>Aim</h3> This study evaluated the immunochromatographic test kits RIDAQUICK N1402, RIDAQUICK N1403, SD BIOLINE Norovirus and ImmunoCard STAT! Norovirus. There are no current publications evaluating RIDAQUICK N1402. <h3>Method</h3> Eighty-six thawed faecal samples previously subjected to viral loading were tested with the kits and the cycle threshold value used as the standard reference. Twenty fresh faecal samples containing norovirus were also tested. <h3>Results</h3> The sensitivity for RIDAQUICK N1403, RIDAQUICK N1402, SD BIOLINE Norovirus, ImmunoCard STAT! Norovirus, using the thawed samples was 46%, 58%, 32% and 47%, respectively. Specificity for RIDAQUICK N1403 was 96% whilst the other test kits obtained 100% specificity. Using the fresh samples, sensitivity was 70% and specificity was 100% across all kits. <h3>Discussion</h3> Variances in sensitivities and specificities across test kits between the thawed and fresh samples indicate the importance of the storage of samples. Immunochromatographic test kits may be useful as a primary screening method for the detection of norovirus, however negative samples should be confirmed with more sensitive detection methods such as reverse transcriptase polymerase chain reaction (RT-PCR).

Comparison between ImmunoCard STAT!® and real-time PCR as screening tools for both O157:H7 and non-O157 Shiga toxin-producing Escherichia coli in Southern Alberta, Canada

An increasing number of non-O157 Shiga toxin-producing Escherichia coli (STEC) infections and outbreaks have been reported. In this study, we evaluated the performance of ImmunoCard STAT!® (Meridian Bioscience, Inc., Cincinnati, OH, USA) as a method to screen stool specimens for STEC (O157 and non-O157). An in-house real-time PCR method was used as the “gold standard”. We also evaluated the prevalence and clinical characteristics of STEC infections in the Alberta South West Zone. From July to November 2011, 819 stool specimens submitted for routine stool culture were tested. With our in-house real-time PCR, 7 O157:H7 and 10 non-O157 STEC isolates were identified for a total of 17 STECs. In comparison, ImmunoCard STAT!® identified a total of 6, resulting in a sensitivity and specificity of 35% and 99%, respectively (P < 0.05). Because of the low sensitivity, ImmunoCard STAT!® cannot be recommended as a routine screening test for STEC from enriched stool specimens. The rate of STEC positivity as detected by PCR was 2.08%, of which 0.86% was O157:H7 and 1.22% non-O157 STEC. Five of the 7 cases of STEC O157 infection experienced bloody diarrhea, and 1 developed hemolytic uremic syndrome.

Comparison of the Diagnostic Accuracy of Five Different Stool Antigen Tests for the Diagnosis of Helicobacter pylori Infection

Several noninvasive diagnostic tests based on the detection of Helicobacter pylori stool antigen (HpSA) have been developed. The aim of the study was to compare the diagnostic accuracy of 5 HpSA tests-2 monoclonal enzyme immunoassay tests (EIAs: the Premier Platinum HpSA Plus test and Helicobacter pylori Antigen (Hp Ag) test) and 3 rapid immunochromatographic assay (ICA) tests (the ImmunoCard STAT! HpSA test, one step HpSA test, and H. pylori fecal antigen test)--for diagnosing H. pylori infection in adult patients with dyspeptic symptoms before eradication therapy. A total of 198 patients with dyspeptic symptoms were included in the study. A gastric biopsy was collected for histopathology and rapid urease testing. Stool specimens for HpSA testing were also collected. Patients were considered H. pylori positive if two invasive tests (histological and rapid urease tests) were positive. The sensitivity and specificity were 92.2% and 94.4%, respectively, for the Premier Platinum HpSA Plus test; 48.9% and 88.9%, respectively, for the HP Ag test; 86.7% and 88.9, respectively, for the One Step HpSA test; 68.9% and 92.6%, respectively, for the ImmunoCard STAT! HpSA test; and 78.9% and 87%, respectively, for the H. Pylori fecal antigen test. The Premier Platinum HpSA Plus EIA test was determined to be the most accurate stool test for diagnosing H. pylori infections in adult dyspeptic patients. The currently available ICA-based tests are fast and easy to use but provide less reliable results.

Comparison of microscopy, rapid immunoassay, and molecular techniques for the detection of Giardia lamblia and Cryptosporidium parvum

Giardia lamblia and Cryptosporidium parvum are recognized as the most common protozoan infections in Saudi Arabia. Microscopic examination of stool samples, either direct or concentrated, for the recovery of G. lamblia cysts and trophozoites and C. parvum oocysts is still the most commonly used for the diagnosis of both parasites. We compared the conventional parasitological techniques of iodine-stained wet mount for G. lamblia and Kinyoun's acid-fast for C. parvum against ImmunoCard STAT® Cryptosporidium/Giardia and real-time polymerase chain reaction (PCR) detecting the 18S rRNA gene of G. lamblia and conventional PCR detecting the same gene of C. parvum at a tertiary hospital in Dhahran, Saudi Arabia. Out of 148 stool samples, 19 and 12 true positives were identified for G. lamblia and C. parvum, respectively, using a composite reference standard. In this case, true positives and negatives were considered as those with at least two positive or negative results out of the three tests. Both ImmunoCard STAT! and PCR methods were more sensitive than the microscopic tests of a single stool specimen of 85.7% (CI=62.6-96.2%) and 85.7% (CI=56.2-97.5%) for G. lamblia and C. parvum, respectively. However, specificity of microscopic tests was higher than other techniques for both parasites. Although PCR seems to be most sensitive for both G. lamblia and C. parvum, its low specificity may render its superiority over other techniques. When a single stool sample is used for detection of G. lamblia and C. parvum, better results can be obtained when coupled with serological testing. Although PCR is the most sensitive method for the detection of both G. lamblia and C. parvum, its use requires attention in relation to the increased possible false positives.

Chromatographic immunoassays for Helicobacter pylori detection--are they reliable in Mali, West Africa?

IntroductionGastrointestinal diseases are major reasons for morbidity in Mali. As Helicobacter pylori is known to play a major role in gastritis and gastric ulcer we wanted to find a simple method for detection.MethodsTwenty-nine volunteers with confirmed gastric ulcer by gastroscopy and 59 randomly selected volunteers were diagnosed by using the rapid serological test Clearview® H. Pylori. The ImmunoCard STAT!® HpSA®test was applied on stool from 65 volunteers seeking help for gastrointestinal related ailments.ResultsA Helicobacter pylori prevalence of 21% was found among the individuals with confirmed gastric ulcer, 44% among the randomly selected volunteers and 14% in individuals with gastrointestinal related ailments.ConclusionAccording to what is already known about the aetiology of gastric ailments and the prevalence of Helicobacter pylori in neighboring countries, the infection rates in our study appear strikingly low. This might indicate that Clearview® H. Pylori and ImmunoCard STAT!® HpSA® have low sensitivities in the populations studied. Strain variability of H. Pylori may be an explanation. The tests need to be properly evaluated in Mali before they can be relied upon as diagnostic tools.

Evaluation of the positive predictive value of a rapid Immunochromatographic test to detect Campylobacter in stools

The recently developed rapid immunochromatographic tests (ICT) have the potential to provide a quick and easy diagnosis of Campylobacter enteritis in comparison to culture. In a previous study we found them sensitive but lacking in specificity. The aim of the present study was to focus on the problem of specificity and determine the positive predictive value (PPV) of a positive result of the ImmunoCard Stat! Campy (Meridian Bioscience, Cincinnati, OH, USA). For this purpose, the stools positive by ICT were cultured according to 3 different protocols: Karmali agar, Preston enrichment broth subcultured on Karmali agar, and a filtration method on a blood agar without antibiotics, all incubated for 7 days at 37°C. Out of 609 stools from adults and children with community acquired enteritis, the reference methods detected 25 positive cases (4.1%) (culture: 19, specific PCR and ELISA both positive: 6) and the ICT: 31 including the 25 true positives. The PPV was 80.6%. We conclude that ICT is a good method to screen Campylobacter positive stools but because of its lack of specificity the positive stools must be tested by another method.