Immunochromatographic Technique Research Articles

Evaluation of Seroprevalence and Risk Factors of Heartworm Infection for Dogs in Rio de Janeiro with Access to Veterinary Care.

Heartworm infection is a chronic disease with clinical signs and effects ranging from an asymptomatic condition to severe disease and death. The prevalence of heartworm disease in the state of Rio de Janeiro has been reported to be high (21.3%). The present study was conducted to evaluate the seroprevalence and risk factors of heartworm infection for the canine population with access to veterinary services in different areas of the state of Rio de Janeiro, Brazil. A total of 1787 canine blood samples were obtained from 135 practices across 8 different areas of Rio de Janeiro state (Rio de Janeiro municipality, São Gonçalo municipality, Niterói municipality, Baixada Fluminense, and the northern, southern, eastern, and mountainous areas) and tested for the presence of Dirofilaria immitis antigens and antibodies against several tick-borne disease pathogens using a commercial immunochromatography technique (Vetscan® Flex 4 Rapid Test; Zoetis; NJ USA). Pet owners reported living conditions, physical characteristics, demographics, and clinical signs for evaluation of risk factors for heartworm infection. Only two evaluated risk factors were shown to enhance the risk for D. immitis infection, including having a short hair coat vs. having a medium or long hair coat (OR 2.62) or positive for antibodies to tick-borne disease parasites (OR 3.83). Clinical signs reported for dogs with heartworm disease were typical for that condition. The overall prevalence of heartworm disease in the state was 8.2%, ranging from 2.4% in the mountainous region to 29.4% in the eastern area. It could not be determined if veterinarians were not diligent about dispensing heartworm preventatives or if poor levels of compliance by dog owners were responsible for higher infection rates in some areas of the state.

Maternal hepatitis B status and Sex at birth: A cross-sectional study in a Ghanaian population

Maternal carrier status of hepatitis B has been associated with excess sons while maternal immunity to it has been associated with excess daughters at birth. However, the proportion of males at birth (sex ratio) is relatively low in Sub-Saharan Africa despite the relatively high prevalence of hepatitis B. However, no known study has tested this hypothesis in the Ghanaian population; hence the aim of the study. The study was cross-sectional between January and September 2023 at the Tamale Central Maternal and Child Health unit. The study involved 380 mothers of whom mothers with daughters (MD) were 145 (38.2 %) while the rest were mothers with sons (MS). The mothers were aged between 18 and 43 years and were sampled within one week of delivery to singleton births. Maternal venous blood samples were collected and tested for hepatitis B surface antigen (HBsAg), surface antibody (HBsAb), envelop antigen (HBeAg) envelope antibody (HBeAb) and core antibody (HBcAb) using immunochromatographic technique and total testosterone (TT), using ELISA. There was no significant difference in the serum total testosterone level between MD and MS (0.32 ± 0.13 vs 0.32 ± 0.27, P = 0.991). Moreover, while the mothers were seropositive for HBsAg (10.5 %), HBsAb (35.5 %), HBeAg (0.0 %), HBeAb (5.3 %) and HBcAb (11.8 %), there was no significant association between sex at birth and maternal hepatitis B status for HBsAg (ꭓ2: 0.531, P = 0.472), HBsAb (ꭓ2: 2.655, P = 0.140), HBeAb (ꭓ2: 0.251, P = 0.633) and HBcAb (ꭓ2: 0.101, P = 1.000). Maternal hepatitis B status may not be associated with the offspring sex at birth in the studied population from Ghana.

Incidence of Helminthic and Viral Coinfections in Malaria Patients in the Tertiary Care Hospital Setup.

This study determines the incidence of common viral and helminth coinfections with malaria in the tertiary care hospital set up in southern Khyber Pakhtunkhwa, Pakistan. The multidimensional research included malaria patients admitted to different hospitals of district Kohat during January and December 2021. Stool samples and blood were assembled from the patients. Giemsa-stained microscopy-positive samples were processed by the immunochromatography technique (ICT) to identify Plasmodium species. Common viral infections such as viral hepatitis (A, B, and C), HIV, and dengue (DENV) were analyzed by ICT kits while SARS-CoV-2 was confirmed through real-time PCR. Furthermore, the intestinal helminths were identified using the Kato-Katz thick smear method. Among 1278 patients, 548 were diagnosed with malaria, 412 (75.2%) were positive for P. vivax infection, 115 (21%) for P. falciparum, and 21 (3.8%) for mixed malaria infection (P. vivax/P. falciparum), with a higher incidence among males (65.2%) than females (34.8%). Coinfection with helminths was positive in 215 (39.3%) malaria patients. The most common infections were caused by the Ascaris lumbricoides species (42.6%) followed by Enterobius vermicularis (31.7%) and hookworm. A total of 24.6% of malaria-positive cases were also coinfected with different viruses with higher frequencies of confection for HAV (8.2%) and DENV (6.2%), respectively. The patients revealed higher incidence of coinfections with P. falciparum (57%) as compared with P. vivax (39.2%) and mixed infections (3.7%). This study demonstrated that the study population exhibited a significant incidence of coinfections with intestinal helminth and viral malaria.

Development of a highly sensitive colloidal gold semiquantitative method for the determination of difenoconazole residues in citrus.

Difenoconazole (DIFE) is a common pesticide used in citrus cultivation; excessive intake can cause neurological damage to the organism, and the existing colloidal gold immunochromatographic test strips cannot meet the requirements for the detection of citrus samples. Difenoconazole test strip was prepared based on the colloidal gold immunochromatographic technique (GICT), and its application in citrus samples was investigated; with colloidal gold (CG) as the probe, the optimization of GICT parameters, and the determination of reaction method, the immunochromatographic test strips for the detection of DIFE in citrus was developed, and the limit of detection (LOD), specificity, accuracy, and stability of the test strips were verified. The results showed that the visual detection limit of the prepared colloidal gold immunochromatographic test strips was 0.2 mg/kg and the quantitative range was 0.06-0.6 mg/kg, and the test strips could specifically identify DIFE and have no cross-reaction with other common triazole pesticides. The detection method established in this study was verified by the GC-MS method, and the detection results achieved good consistency (R2 > 0.98). The test strips developed in this study have good performance and can be used for highly sensitive detection of citrus samples.

Epidemiological survey of infectious agents in free-ranging maned wolves (Chrysocyon brachyurus) in Northeastern Brazil.

Infectious diseases are one of the most concerning threats to maned wolves (Chrysocyon brachyurus) due to the potential impact on free-ranging populations. The species is currently classified as vulnerable according to the national list of threatened species and occurs mainly in open habitats, such as the Cerrado, a tropical savannah, which comprises its main distribution area in Brazil. In the northeastern region, it occurs in the Cerrado of Bahia, Piauí, Maranhão, and Tocantins states. Therefore, this study aimed to investigate the occurrence of infectious agents in Chrysocyon brachyurus through an epidemiological assessment of free-ranging individuals in western Bahia, specifically in the Barreiras microregion, a Cerrado area intensely fragmented and anthropized by agricultural activity. Eleven specimens were evaluated for serological titration, antigen research, and genetic material research for canine distemper virus (CDV), canine parvovirus (CPV), adenovirus-canine-type 1 (CAdV-1), canine coronavirus (CCoV), Leptospira interrogans and Toxoplasma gondii from 2020 to 2022. In addition to maned wolves, domestic dogs were also evaluated and tested. All maned wolves (100%) evaluated by the dot-ELISA technique exhibited immunoglobulin M (IgM) and seven (64%) exhibited immunoglobulin G (IgG) against CDV and CPV, while 100% exhibited IgG against CDV when using the immunochromatographic technique. Regarding CAdV-1, 90% were seropositive for IgG, while 64% exhibited IgG against T. gondii. Nine dogs from the region were also sampled, and all (100%) exhibited IgM and IgG against CDV and CPV. For IgG against T. gondii and against CAdV-1, 90% of the animals were seropositive. Molecular evaluation yielded negative results for all maned wolves and dogs assessed for CAdV-1, CDV, and T. gondii, as well as the CCoV antigen. These data indicate the occurrence of viral agents and Toxoplasma gondii in maned wolves and dogs, suggesting circulation in both populations.

Immunochromatographic Detection of SARS CoV-2 Antigen In Comparison With the Polymerase Chain Reaction for Laboratory Diagnosis of Covid-19 in Karachi, Pakistan

Introduction: The Covid-19 pandemic raised the question of which laboratory test was relevant for a rapid and accurate diagnosis of the disease. The current two methods for the detection of SARS CoV-2 are the ICT (Immunochromatographic Technique) and the PCR (Polymerase Chain Reaction) tests; therefore comparative analysis of test performance has to be done. Objective: To perform a comparative analysis of two different techniques (Immunochromatographic technique for Antigen and Polymerase Chain Reaction for RNA) which are implicated for the detection of SARS CoV-2. Materials & Methods: The Rapid Antigen Test (RAT) and Polymerase Chain Reaction (PCR) were performed for the detection of Covid-19 on individuals having the signs and symptoms of SARS Covid-19. Immunochromatographic technique (ICT) was performed by SD Biosensor kits, while for Polymerase Chain Reaction RNA extraction was performed by Liferiver® auto extraction analyzer, and amplification was performed by SLAN®-48P Real-Time PCR System. Results: Among of 100 samples tested, 62 (23.56%) were positive on ICT while PCR had 66 (22.44%) and 38 were negative on ICT while PCR had 34. Thus the sensitivity of ICT was 90.77% (95% CI, 80.98% - 96.54%) and specificity was 91.43% (95% CI 76.94%-98.20%). The Positive Predictive Value was 95.16% while the Negative Predictive Value was 84.21%. However the Cohen’s Kappa Index Value was recorded as 0.806. Conclusion: The clinical performance of SD Biosensor Roche kits was excellent. On the basis of sensitivity and specificity it was concluded that RAT have comparable results with RT PCR. Keywords: Antigen, COVID-19, diagnosis, immunoassay, PCR, SARS-CoV-2.

Frequency, distribution and determinants of Helicobacter pylori infection in adults and adolescents with gastric symptoms: cross-sectional epidemiological inquiry in district Haripur, Pakistan.

Helicobacter pylori (HP) is a vital element in the etiology of peptic ulcers and gastric cancer. This research aimed to determine the frequency, distribution, and determinants of HP infection in adults and adolescents with gastric symptoms in district Haripur, Khyber Pakhtunkhwa, Pakistan. This cross-sectional study was performed from June 2018 to June 2020 at the Medical Laboratory Technology Department, The University of Haripur, Pakistan. Presence of HP was a research variable, while sex, age groups, education status, overcrowding, dining habits, milk intake, drinking water source and animal contact were grouping variables. Immuno-chromatographic technique (ICT) was used to for serological detection of HP antibodies. All variables were represented by frequency and percentage with 95%CI. Prevalence of HP and its distribution by eight socio-demographic variables was testified by the chi-square goodness-of-fit test while association was testified by chi-square test of association. Out of total 1160 cases, 557 (48%) were positive for HP. Population prevalence was higher in men, in the age group 20-40 years, illiterate, family size ≤ 10 persons, taking restaurant food, using tetra pack, using municipal water, and having animal contact. The observed prevalence of HP was similar to its expected prevalence in the population. The observed distribution of HP in the sample was different from its expected distribution in population by eight socio-demographic variables. Presence of HP was associated with all eight socio-demographic variables besides age groups.

Comparative analysis of three immunochromatographic test strips for rapid detection of cadmium ion in Asparagus

SummaryCurrently, there is increasing concern regarding the presence of cadmium ion (Cd2+) residues in Asparagus, necessitating the development of a rapid, sensitive and effective detection method. Immunochromatographic detection techniques offer a swift and efficient primary screening approach, significantly reducing labour and material resources compared to traditional detection methods. In this study, we aimed to construct and optimise an immunochromatographic test strip method for precise determination of Cd2+ content in Asparagus. To achieve this, monoclonal cadmium antibody (4A9) was prepared and conjugated with colloidal gold nanoparticles (AuNPs), latex microspheres (LM) and polydopamine (PDA) to create immunoprobes for test strip construction. We optimised key factors, such as probe parameters, strip assembly conditions and sample pretreatment methods. The sensitivity and detection capabilities of the three test strips were evaluated using actual Asparagus samples. The results demonstrated that all three immunochromatographic test strips exhibited high sensitivity, efficiency and rapidity in detecting Cd2+ levels in Asparagus. Notably, the LM‐based and PDA‐based test strips showed outstanding performance, with a visual limit of detection (vLOD) of 0.1 ng mL−1 and an elimination value of 2.0 ng mL−1. These findings underscore the promising potential of these test strips for practical cadmium detection in Asparagus samples.

Distribution of Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2) Immunoglobulins G and M among Frontline Health Workers in Eleme Local Government of Rivers State, Nigeria

Background: The fight against Corona Virus Disease (COVID-19) globally among front line health workers has been a challenging task, it encompasses working lengthy hours at the isolation Centre’s, intensive care units, emergency departments and molecular laboratories, and also been exposed to pathogens, fatigue, and psychological distress. This has led to high morbidity and mortality rate among front line health workers all over the globe.
 Aim: This study aimed at determining the distribution of SARS CoV -2 IgG and IgM among frontline health workers in Eleme Local Government of Rivers State, Nigeria.
 Materials and Methods: A total of 100 frontline Covid-19 health workers were recruited for this study comprising 48 males and 52 females with ages between 23 and 49 years and included janitors, hygienist, nurses, data Officers, logistics and ambulance drivers, physicians, and medical laboratory scientists, working at the molecular laboratories, sample collection booths and isolation center. The bio-data of the subjects were obtained using a well-structured questionnaire. Only subjects who gave informed consent were recruited for this study. 60ul of capillary blood was collected from each participant using an aseptic technique and immediately followed by the analysis of SAR-CoV-2 IgM and IgG using a lateral flow immunochromatographic assay technique.
 Results: Results from this study showed a total of forty-two (42) 42% subjects were reactive to IgG antibodies while fifty-eight (58) 58% subjects were non-reactive to IgG antibodies also a total of Twenty-One (21) 21% subject were reactive to IgM antibodies while a total of seventy-nine (79) 79% subjects were none reactive to IgM antibodies. A total of nine (9) subjects who were exposed to SAR-CoV-2 for more than one year were reactive to SAR-Cov-2 IgM and IgG antibodies, while a total of two (2) subjects who were exposed to SAR-CoV-2 for less than one year were reactive to SAR-Cov-2 IgM and IgG antibodies and the difference (p ₌ 0.013) was statistically significant. Also, a higher number of subjects within the 20-29 age bracket were reactive to SAR-CoV-2 IgM antibodies while subjects with in the age bracket of 30-39 were more reactive to IgG antibodies.
 Conclusion: This study reveals that serological testing is an ideal approach in assessing the proportion of frontline health workers who might have been exposed to SARS-CoV-2 as part of effort in combating COVID-19 disease globally.

A COMPARATIVE STUDY OF CHEMILUMINISCENCE IMMUNOASSAY (CLIA) AND IMMUNOCHROMATOGRAPHIC TECHNIQUE (ICT) FOR ?-THALASSEMIA (MAJOR) PATIENTS IN LOCAL POPULATION

The sustainability of beta thalassemia (major) patients is dependent on regular blood transfusion so they are at a greater risk of acquiring transfusion transmitted infections (TTIs). The objective of this research project was to compare the efficiency of two blood screening techniques such as chemiluminescence immunoassay (CLIA) and immunochromatographic technique (ICT) for the detection of transfusion transmitted infections in ?-thalassemia (major) Patients in local population. For this purpose, 250 blood samples were collected and screened through CLIA and ICT. Results showed that 30% of the samples were positive for different infectious diseases like hepatitis B or C virus, Human immunodeficiency virus (HIV) infections, and infections with syphilis or malarial agents, while 70% of samples were free from any kind of infections. Among all the infectious diseases the incidence of hepatitis C virus (HCV) was the highest i.e., 23.6% and 26.4% incidence of HCV was recorded through ICT and CLIA respectively. The second highest incidence was of hepatitis B virus followed by the other infectious diseases. The results showed that CLIA was more sensitive as compared to ICT in detecting the infections in blood. All blood banks and transfusion centers need to implement authentic screening of blood to counter the TTIs.

Correlation between Hepatic Enzymes and Viral Load of HBV in Hepatitis B patients

Background: Hepatitis B virus is a causative agent of hepatitis B, and it is a severe global health issue. Aim: To investigate the increased level of aminotransferases and its association with viral load of HBV infected patients and to find the most sensitive and reliable technique for identification of HBV infection. Methods: This cross-sectional study included 198 patients of HBV. Blood samples were collected from these patients in serum tubes for detection of HBV by different techniques such as Immunochromatographic (ICT), Enzyme linked immunosorbent assay (ELISA), and whole blood was collected which was further processed for DNA extraction and real time PCR. Results: There were 64 female and 134 males in this study. All the patients were positive for HBV by the ICT method and also by ELISA method but for the RT-PCR out of these 198 patients 89(45%) were positive and 109 (55%) were negative. This study demonstrates no significant correlation between liver enzymes with viral load. The ICT test method is active and simple but not a precise and unique test also has no statistical correlation with viral load, but ELISA is correlated with viral load recognized by real time PCR. (P value=˂0.001, 95% Cl=0.40-0.69, r value =0.56). Conclusion: Our results concluded that the immunochromatographic technique is fast and easily available but not a precise and definitive test and has no statistical correlation with viral load, but ELISA is associated with viral load proved by RT-PCR. Real time polymerase chain reaction is the gold standard test for the detection of Hepatitis B virus infection. The practical implication of this study is that ICT technique is no longer a reliable technique for the diagnosis of HBV infection and the patients positive on ICT should be confirmed for HBV in PCR for both diagnostic and prognostic purposes. Keywords: Hepatitis B Virus, Liver enzymes, Immunochromatographic, Viral load, Enzyme linked immunosorbent assay

POINT OF CARE PCR FOR INFLUENZA AND RESPIRATORY SYNCYTIAL VIRUS: FROM THE LAB TO THE EMERGENCY ROOM

RNA viruses, such as influenza and respiratory syncytial virus (RSV), are common causes of lower airway infections. Rapid tests (antigen-based by immunochromatographic and molecular technique - RIT and RMT, respectively) with good diagnostic accuracy directly impacts the quality of patient care and hospitalization costs. This study aims to evaluate the implementation of point of care PCR compared to rapid antigen-based tests for influenza and RSV in the emergency department.Methods: Prospective cross section study in an Emergency Room (ER) from August to September 2019, where all patients with influenza like illness went through RIT and RMT. The patients were divided in a model of four clinical scenarios to evaluate cost and isolation time in the ER.Results: 424 patients were included in the study. RIT showed sensitivity of only 40% compared with RMT (100% specificity; PPV 100%; NPV 68,7%), causing 103 patients to mistakenly leave respiratory isolation, raising biological risk in the ER. Fast results from RMT led negative patients to leave isolation early (262:10 less hours of isolation), allowing cost reduction of USD 1.921,20. Nonetheless, RMT had higher cost than RIT in all clinical scenarios with an increase of USD 12.788,90 (69,9% of cost related to tests and isolation precautions). Conclusion: RIT was a more affordable test but can’t be used to exclude disease and was associated with higher biological risk to the hospital setting. RMT had better diagnostic performance with faster results, allowing for less isolation time per patient tested.

SEROPREVALENCE OF HELICOBACTER PYLORI AND HEPATITIS A VIRUS AMONG ORPHANAGE CHILDREN IN SANA’A, YEMEN

Background: The epidemiological association between Helicobacter pylori (H. pylori) and hepatitis A virus (HAV) has been evaluated by different groups with conflicting conclusions. Aims: The aim of this study was to determine the prevalence of hepatitis A virus and H. pylori infection among children of an orphanage in Sana'a, and to identify the socio-demographic factors associated with their prevalence, both individually and simultaneously. Methods: This is a cross-sectional study carried out among 200 orphaned children who lived at Ahmed's orphanage in Sana’a City, Yemen during the period from October 2022 to February 2023. The stool and blood specimens were collected and the required data were filled in pretested questionnaire. By using the immunochromatographic assay technique, the seropositivity of the HAV antibody was screened in blood plasma while the H. pylori antigen was detected in stool. The obtained results were analyzed using SPSS software. Results: Out of 200 participants; 2(1%) were positive for anti-HAV and 63(31.5%) for H. pylori antigen. The HAV and H. pylori infections, respectively, were significantly higher in the group aged 10-12 and 13-15 years, attending a primary and preparatory school, living with 3-5 individuals/room, their family infected with hepatitis A and H. pylori, and received a blood transfusion. The high risk of hepatitis A infection was in children who their family was infected by HAV and received a blood transfusion while H. pylori was in subjects who had a history of hospitalizations and whose family infected by H. pylori. Conclusion: The high number of children suffering from both H. pylori and HAV antibodies among orphans in Sana'a indicates a high prevalence rate in the community. It is possible that this high prevalence reflects a prevalence specific to this group or age, and this connection is real. Peer Review History: Received: 26 February 2023; Revised: 11 March; Accepted: 17 April 2023, Available online: 15 May 2023 Academic Editor: Dr. Muhammad Zahid Iqbal, AIMST University, Malaysia, drmmziqbal@gmail.com Received file: Reviewer's Comments: Average Peer review marks at initial stage: 5.0/10 Average Peer review marks at publication stage: 7.0/10 Reviewers: Dr. Bilge Ahsen KARA, Ankara Gazi Mustafa Kemal Hospital, Turkey, ahsndkyc@gmail.com Prof. Hassan A.H. Al-Shamahy, Sana'a University, Yemen, shmahe@yemen.net.ye

Prevalence of Transmissible Infectious Diseases among Healthy Blood Donors in Faisalabad, Pakistan

Blood transfusions are necessary due to the increased incidence of blood diseases and an increase in automobile accidents. In healthcare systems with limited resources, the provision of safe blood products is hampered by transfusion-transmitted diseases (TTIs), such as the hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), syphilis, and malaria. Objective: To determine how common TTIs are among blood donors in Faisalabad. Methods: Immuno-chromatographic technique (ICT) kits and thick film (malaria) screening were used to test donors for HBV, HCV, HIV, syphilis, and malaria. Results: Among 1500 donors, prevalence of HCV was highest (n=106), followed by HBV (n=42), syphilis (n=11), and malaria (n=3). One positive case was reported as HIV. Between the ages of 21 and 40, donors who tested positive were more prevalent. Conclusions: By more carefully evaluating and screening each donor before selecting them for blood donation, safe blood transfusions can both increase recipient safety and reduce the spread of TTIs.

Evaluation of Two Assays Immunochromatography and RT-PCR for detection of Rotavirus in Iraqi Children

The lack of dedicated RV treatment makes early detection and effective vaccines important to prevent increased mortality and morbidity, as they can only be treated with fluid and electrolyte replacement. The study's goal was to assess the specificity and sensitivity of Reverse transcriptase PCR and Rapid immunochromatography techniques for Rotavirus detection. Between November 2020 and June 2021, 320 stool samples from children under the age of five were obtained at Babylon Teaching Hospital. Primary detection of Rotavirus contamination has executed the use of immunochromatography test (rapid test) LumiQuickAdeno-RotaVirus Antigen Comb takes a look at(Netherlands) and opposite transcriptase PCR in the detection of Rotavirus infection by means of using structural gene (vp4), the results discovered that Rotavirus became detected at a high rate in male stool samples (67.5%) rather than a girl (32.5%). December and Januarywere observed the biggest number of cases, with (46.6%) and (28.3%), respectively.The rural area had the highest rate of Rotavirus infection (56.6%), compared to (43.4%) in the urban area.The RT-PCR assay's excellent overall performance was also considered in its capability to identify Rotavirus RNA in 84 of 320 children's prevalence (26.25%).

Rapid quantitative detection of Klebsiella pneumoniae in infants with severe infection disease by point-of-care immunochromatographic technique based on nanofluorescent microspheres.

Background: Klebsiella pneumoniae (KP, K. pneumoniae) is one of the most important nosocomial pathogens that cause severe respiratory infections. As evolutionary high-toxic strains with drug resistance genes increase year by year, the infections caused by it are often accompanied by high mortality, which may be fatal to infants and can cause invasive infections in healthy adults. At present, the traditional clinical methods for detecting K. pneumoniae are cumbersome and time-consuming, and the accuracy and sensitivity are not high. In this study, nanofluorescent microsphere (nFM)-based immunochromatographic test strip (ICTS) quantitative testing platform were developed for point-of-care testing (POCT) method of K. pneumoniae. Methods: 19 clinical samples of infants were collected, the genus-specific gene of mdh was screened from K. pneumoniae. Polymerase chain reaction (PCR) combined with nFM-ICTS based on magnetic purification assay (PCR-ICTS) and strand exchange amplification (SEA) combined with nFM-ICTS based on magnetic purification assay (SEA-ICTS) were developed for the quantitative detection of K. pneumoniae. The sensitivity and specificity of SEA-ICTS and PCR-ICTS were demonstrated by the existing used classical microbiological methods, the real-time fluorescent quantitative PCR (RTFQ-PCR) and PCR assay based on agarose gel electrophoresis (PCR-GE). Results: Under optimum working conditions, the detection limits of PCR-GE, RTFQ-PCR, PCR-ICTS and SEA-ICTS are 7.7 × 10-3, 2.5 × 10-6, 7.7 × 10-6, 2.82 × 10-7ng/μL, respectively. The SEA-ICTS and PCR-ICTS assays can quickly identify K. pneumoniae, and could specifically distinguish K. pneumoniae samples from non-K. pneumoniae samples. Experiments have shown a diagnostic agreement of 100% between immunochromatographic test strip methods and the traditional clinical methods on the detection of clinical samples. During the purification process, the Silicon coated magnetic nanoparticles (Si-MNPs) were used to removed false positive results effectively from the products, which showed of great screening ability. The SEA-ICTS method was developed based on PCR-ICTS, which is a more rapid (20min), low-costed method compared with PCR-ICTS assay for the detection of K. pneumoniae in infants. Only need a cheap thermostatic water bath and takes a short detection time, this new method can potentially serve as an efficient point-of-care testing method for on-site detection of pathogens and disease outbreaks without fluorescent polymerase chain reaction instruments and professional technicians operation.

Analysis of the reliability of rapid diagnostic tests for varicella, including breakthrough cases.

In the era of universal varicella vaccination, diagnosis of varicella is challenging, especially for breakthrough cases. We sought to clarify the reliability of direct varicella-zoster virus (VZV) loop-mediated isothermal amplification (LAMP) and DermaQuick® VZV using the immunochromatography technique as rapid diagnostic tests for varicella. In addition, the usefulness of saliva as a sample type for direct LAMP was investigated. Among the 46 enrolled patients with suspected VZV infection, 31 patients (67.3%) were positive for the nucleic acid test based on real-time PCR from skin swab samples. Direct LAMP of skin swabs was positive in 29 (63.0%) of 46 patients. DermaQuick® VZV was positive in 25 (54.3%) of 46 patients. VZV DNA was detected in only 48.4% of oral swabs with the direct LAMP method. With real-time polymerase chain reaction (PCR) as the standard for diagnosing varicella, the sensitivity and specificity of DermaQuick® VZV were 80.7% and 100%, respectively. The sensitivity and specificity of direct LAMP from skin swabs were 93.6% and 100%, respectively. The sensitivity and specificity of real-time PCR for DNA extracted from oral swabs were 74.2% and 93.3%, respectively. Thus, oral swab samples are not suitable for breakthrough varicella diagnosis. Although DermaQuick® VZV is considered the most convenient point-of-care test for varicella, its sensitivity and specificity were lower than those of direct VZV LAMP.

Preparation of monoclonal antibodies against norovirus and establishment of a rapid immunochromatographic technique

The established colloidal gold test strip detection method can be used for the detection of common Norovirus strains and in large-scale epidemiological investigations.

372. Analysis of the reliability of rapid diagnostic tests for varicella patients, including breakthrough cases

Abstract Background In the era of universal varicella vaccination, diagnosis of varicella is challenging, especially for breakthrough cases. We sought to clarify the reliability of direct varicella-zoster virus (VZV) loop-mediated isothermal amplification (LAMP) and DermaQuick® VZV using the immunochromatography technique as rapid diagnostic tests for varicella. In addition, the usefulness of saliva as a sample type for direct LAMP was also investigated. Methods Between April 2019 and January 2021, 46 patients suspected VZV infection were enrolled in this study. Written informed consent was obtained from the parents of all participants. This study was approved by the institutional review board of Fujita Health University (No. 15–247). Samples were collected from skin eruptions using two different swabs. one swab which was soaked in 1 mL of isotonic saline was used for direct VZV LAMP and the other swab which was immersed in 500 µL of DermaQuick® VZV reaction buffer was used for DermaQuick® VZV. The isotonic saline solution used to wash the oral swab sample was used for direct VZV LAMP. The DNA extracted from the solutions were used for real-time PCR analysis. Results Thirty one patients (67.3%) were diagnosed with varicella based on real-time PCR of skin swabs. Direct LAMP of skin swabs was positive in 29 (63.0%) of 46 patients. DermaQuick® VZV was positive in 25 (54.3%) of 46 patients. The sensitivity for direct LAMP of skin swabs, DermaQuick® VZV, direct LAMP of oral swabs, and real-time PCR of oral swabs was 93.6% (95% confidence interval [CI], 79.3–98.9%), 80.7% (95% CI, 63.7–90.8%), 48.3% (95% CI, 32.0–65.1%), and 74.2% (95% CI, 56.8–86.3%), respectively. The sensitivity and specificity of real-time PCR for DNA extracted from oral swabs was 74.2% (95% CI, 56.8–86.3%) and 93.3% (95% CI, 79.8–99.7%), respectively. Conclusion Although DermaQuick® VZV is the most convenient point-of-care test for varicella, the sensitivity and specificity of this method were slightly lower than those of direct VZV LAMP. Disclosures All Authors: No reported disclosures.

Seroprevalence of Hepatitis B Virus Infection among Nursing Students in Karachi

OBJECTIVE To determine the prevalence of hepatitis B virus infection among nursing students. METHODOLOGY We conducted a cross-sectional study in eight nursing schools (Four private and Four public) in Karachi and selected randomly 25 diploma nursing students from each school of nursing. Venous blood was obtained from nursing students and was serologically tested using the ICT (Immunochromatographic Technique) method. A questionnaire form was used to obtain data related to the socio-demographic characteristics of the participants. Data was analyzed using SPSS version 21. RESULTS A total of 200 student nurses participated in this research study. Out of 200 student nurses in the study, 113 (56.5 %) were male, and 87(43.5 %) were female, 82 (41 %) . 1 % of the nursing students were serologically positive for HBV. CONCLUSION Health care workers are at high risk of getting viral hepatitis. A program for education about occupational risk factors and regular blood screening must be implemented in all healthcare setups of Karachi to reduce the burden of HBV infection.