Test-positive Samples Research Articles

Genetic characterization of low-pathogenic avian influenza subtypes H10N6 and H10N7 from free-grazing ducks in Thailand.

Free-grazing duck (FGD) raising is a unique domestic duck production system that is widely practiced in several Asian countries, including Thailand. FGD is a significant reservoir for influenza A viruses (IAVs). In this study, we genetically characterized IAV-H10N6 and IAV-H10N7 isolated from avian influenza surveillance in FGDs in Thailand. We collected 640 swab samples from 29 FGD flocks located in 6 provinces of Thailand. IAVs were isolated from swab samples using egg inoculation. Hemagglutination test-positive samples were then subjected to IAV detection. Viral RNA was subjected to IAV detection using real-time reverse-transcription polymerase chain reaction (rRT-PCR) specific to matrix (M) gene. IAV subtypes were identified using the RT-PCR assay specific to all hemagglutinin and neuraminidase subtypes. Whole-genome sequencing of IAVs was performed to genetically characterize IAV-H10N6 and IAV-H10N7. Our results showed that 41 (6.41%) samples tested positive for IAV using rRT-PCR specific to the M gene. Among these, only two IAVs were subtypes as IAV-H10N6 and IAV-H10N7 and were subjected to whole-genome sequencing. IAV-H10N6 and IAV-H10N7 belonged to the Eurasian lineage and did not show any evidence of reassortment from the North American lineage. The viruses exhibited low-pathogenic characteristics and preferred binding to avian-type receptors. Genetic analysis revealed no mutations in PB2 and M genes, unlike human IAV-H10N3 and IAV-H10N8, which exhibited increased virulence in mammals. IAV-H10N6 and IAV-H10N7 viruses have less potential as zoonotic viruses. However, IAV in FGDs should be monitored for novel reassortant or zoonotic viruses. This study provides information on the genetic characteristics and diversity of IAV-H10N6 and IAV-H10N7 that are circulated in FGDs in Thailand.

SARS-CoV-2 seroprevalence in pregnant women in Kilifi, Kenya from March 2020 to March 2022.

Seroprevalence studies are an alternative approach to estimating the extent of transmission of SARS-CoV-2 and the evolution of the pandemic in different geographical settings. We aimed to determine the SARS-CoV-2 seroprevalence from March 2020 to March 2022 in a rural and urban setting in Kilifi County, Kenya. We obtained representative random samples of stored serum from a pregnancy cohort study for the period March 2020 to March 2022 and tested for antibodies against the spike protein using a qualitative SARS-CoV-2 ELISA kit (Wantai, total antibodies). All positive samples were retested for anti-SARS-CoV-2 anti-nucleocapsid antibodies (Euroimmun, ELISA kits, NCP, qualitative, IgG) and anti-spike protein antibodies (Euroimmun, ELISA kits, QuantiVac; quantitative, IgG). A total of 2,495 (of 4,703 available) samples were tested. There was an overall trend of increasing seropositivity from a low of 0% [95% CI 0-0.06] in March 2020 to a high of 89.4% [95% CI 83.36-93.82] in Feb 2022. Of the Wantai test-positive samples, 59.7% [95% CI 57.06-62.34] tested positive by the Euroimmun anti-SARS-CoV-2 NCP test and 37.4% [95% CI 34.83-40.04] tested positive by the Euroimmun anti-SARS-CoV-2 QuantiVac test. No differences were observed between the urban and rural hospital but villages adjacent to the major highway traversing the study area had a higher seroprevalence. Anti-SARS-CoV-2 seroprevalence rose rapidly, with most of the population exposed to SARS-CoV-2 within 23 months of the first cases. The high cumulative seroprevalence suggests greater population exposure to SARS-CoV-2 than that reported from surveillance data.

Bayesian true prevalence estimation of brucellosis in sheep, goats, cattle and camels in southeast regions of Iran.

Brucellosis is worldwide one of the most prevalent zoonotic diseases with serious public health hazard affecting domestic livestock and causing economic losses. Objective of this study is to estimate the true prevalence of brucellosis in livestock, specifically cattle, sheep, goats and camels, using a novel Bayesian latent class model, adjusting for the imperfect sensitivity and specificity of the applied tests, where the second test was restricted only to first test-positive samples. Brucellosis seems more prevalent in goats and sheep, while the posterior medians and 95% probability intervals (95% PI) for the average true prevalence for sheep, goats, cattle and camels are 18% (4%-43%), 19% (7%-37%), 16% (5%-34%) and 18% (1%-48%) respectively. The study results indicate that brucellosis is highly endemic in Iran and crucial steps are needed to control and raise awareness about the high public health concern of the disease.

Interactions among acute respiratory viruses in Beijing, Chongqing, Guangzhou, and Shanghai, China, 2009-2019.

A viral infection can modify the risk to subsequent viral infections via cross-protective immunity, increased immunopathology, or disease-driven behavioral change. There is limited understanding of virus-virus interactions due to lack of long-term population-level data. Our study leverages passive surveillance data of 10 human acute respiratory viruses from Beijing, Chongqing, Guangzhou, and Shanghai collected during 2009 to 2019: influenza A and B viruses; respiratory syncytial virus A and B; human parainfluenza virus (HPIV), adenovirus, metapneumovirus (HMPV), coronavirus, bocavirus (HBoV), and rhinovirus (HRV). We used a multivariate Bayesian hierarchical model to evaluate correlations in monthly prevalence of test-positive samples between virus pairs, adjusting for potential confounders. Of 101,643 lab-tested patients, 33,650 tested positive for any acute respiratory virus, and 4,113 were co-infected with multiple viruses. After adjusting for intrinsic seasonality, long-term trends and multiple comparisons, Bayesian multivariate modeling found positive correlations for HPIV/HRV in all cities and for HBoV/HRV and HBoV/HMPV in three cities. Models restricted to children further revealed statistically significant associations for another ten pairs in three of the four cities. In contrast, no consistent correlation across cities was found among adults. Most virus-virus interactions exhibited substantial spatial heterogeneity. There was strong evidence for interactions among common respiratory viruses in highly populated urban settings. Consistent positive interactions across multiple cities were observed in viruses known to typically infect children. Future intervention programs such as development of combination vaccines may consider spatially consistent virus-virus interactions for more effective control.

Immunoassay-based evaluation of rOmp28 protein as a candidate for the identification of Brucella species.

Introduction. Brucellosis is an important bacterial zoonosis, re-emerging as a serious public health concern in developing countries. Two major species, Brucella melitensis and Brucella abortus, cause recurrent facile infection in human. Therefore, rapid and accurate diagnosis for early disease control and prevention is needed in areas with low disease burden.Hypothesis. This study evaluated the sandwich enzyme-linked immunosorbent assay (ELISA) (S-ELISA) immunoassay for potential use of whole-cell (WC) and recombinant outer-membrane protein (rOmp28)-derived IgG polyclonals in sensitive detection of Brucella.Aim. Immunoassay-based WC detection of Brucella species in important sub-clinical matrices at lower limits of detection.Methodology. We purified recombinant rOmp28 with Ni-NTA gel affinity chromatography and produced IgG polyclonal antibodies (pAbs) using BALB/c mice and New Zealand white female rabbits against different antigens (Ags) of Brucella. Checkerboard sandwich ELISA and P/N ratio (optical density of 'P' positive test sample to 'N' negative control) were used for evaluation and optimization of the study. The pAbs were characterized using Western blot analysis and different matrices were spiked with WC Ag of Brucella.Results. Double-antibody S-ELISA was developed using WC Ag-derived rabbit IgG (capture antibody at 10 µg ml-1) and rOmp28-derived mice IgG (detection antibody at 100 µg ml-1) with a detection range of 102 to 108 cells ml-1 and a limit of detection at 102 cells ml-1. A P/N ratio of 1.1 was obtained with WC pAbs as compared to 0.6 and 0.9 ratios with rOmp28-derived pAbs for detecting B. melitensis 16M and B. abortus S99, respectively. An increased P/N ratio of 4.4 was obtained with WC Ag-derived rabbit IgG as compared to 4.2>4.1>2.4 ratios obtained with rabbit IgGs derived against cell envelope (CE), rOmp28 and sonicated antigen (SA) of Brucella with high affinity for rOmp28 Ag analysed on immunoblots. The rOmp28-derived mice IgG revealed two Brucella species at P/N ratios of 11.8 and 6.3, respectively. Upon validation, S-ELISA detected Brucella WCs in human whole blood and sera samples with no cross-reactivity to other related bacteria.Conclusion. The developed S-ELISA is specific and sensitive in early detection of Brucella from different matrices of clinical and non-clinical disease presentation.

Molecular Profiling of 50 734 Bethesda III-VI Thyroid Nodules by ThyroSeq v3: Implications for Personalized Management.

Comprehensive genomic analysis of thyroid nodules for multiple classes of molecular alterations detected in a large series of fine needle aspiration (FNA) samples has not been reported. To determine the prevalence of clinically relevant molecular alterations in Bethesda categories III-VI (BCIII-VI) thyroid nodules. This retrospective analysis of FNA samples, tested by ThyroSeq v3 using Genomic Classifier and Cancer Risk Classifier at UPMC Molecular and Genomic Pathology laboratory, analyzed the prevalence of diagnostic, prognostic, and targetable genetic alterations in a total of 50 734 BCIII-VI nodules from 48 225 patients. Among 50 734 informative FNA samples, 65.3% were test-negative, 33.9% positive, 0.2% positive for medullary carcinoma, and 0.6% positive for parathyroid. The benign call rate in BCIII-IV nodules was 68%. Among test-positive samples, 73.3% had mutations, 11.3% gene fusions, and 10.8% isolated copy number alterations. Comparing BCIII-IV nodules with BCV-VI nodules revealed a shift from predominantly RAS-like alterations to BRAF V600E-like alterations and fusions involving receptor tyrosine kinases (RTK). Using ThyroSeq Cancer Risk Classifier, a high-risk profile, which typically included TERT or TP53 mutations, was found in 6% of samples, more frequently BCV-VI. RNA-Seq confirmed ThyroSeq detection of novel RTK fusions in 98.9% of cases. In this series, 68% of BCIII-IV nodules were classified as negative by ThyroSeq, potentially preventing diagnostic surgery in this subset of patients. Specific genetic alterations were detected in most BCV-VI nodules, with a higher prevalence of BRAF and TERT mutations and targetable gene fusions compared to BCIII-IV nodules, offering prognostic and therapeutic information for patient management.

RAPID DETECTION OF SARS COV-2 INFECTION IN COMPARISION WITH RT-PCR IN TERTIARY CARE HOSPITAL

Objectives: The goal of the present study was to assess the SARS-CoV-2 antigen detection test’s performance features and compare them to the real-time reverse transcription polymerase chain reaction (RT-PCR) test, the gold standard test for the diagnosis of COVID-19 cases. Methods: From October 2020 to May 2021, patients attending the OPD, including those undergoing surgery, at a Tertiary Care Teaching Hospital in Telangana provided 1000 respiratory samples, primarily nasopharyngeal swabs. A skilled technician had collected two nasopharyngeal swabs from each person in a COVID sample collection room while wearing personal protective equipment and following strict infection control procedures. One swab was used for the rapid antigen test given by the standard Q COVID-19 Ag test kit and placed into the extraction buffer tube. Second swab was kept in the viral transport medium and used for Allplex™ 2019-nCoV Assay (Seegene, Korea), which targets envelope gene (E), and RNA dependent RNA polymerase (RdRp) and nucleocapsid (N) genes of SARS CoV-2, was used for SARS-CoV-2 RNA detection according to the manufacturer’s instructions. Results: Out of 1000 samples tested for COVID-19, 623 (63.7%) were males and 377 (36.3%) were females. Out of 1000 samples, 347 samples were RT-PCR positive and 653 were RT-PCR negative. Out of 347 RT-PCR samples positive, 341 were Rapid antigen test positive samples and six were negative. Overall sensitivity and specificity are 98.27% and 99.85%, respectively. Conclusion: The real-time RT-PCR assay’s sensitivity and specificity were comparable to those of the rapid assay for SARS-CoV-2 antigen detection. It can be utilized for contact tracing measures to control the COVID-19 pandemic in places such as border crossings, airports, interregional bus and train stations, and mass testing campaigns needing quick findings. This is especially true in areas with a high prevalence of the disease.

Lupus anticoagulant laboratory diagnosis by applying the 2020 ISTH-SSC guidelines

BackgroundThe ISTH-SSC guidelines for lupus anticoagulant (LA) testing recommend using in-house determined cut-off values, pooled normal plasma (PNP) for ratio normalization, and a ratio for the mixing test interpretation. They strongly support the mixing step role in the diagnostic process. ObjectivesTo investigate and compare the LA testing results and interpretations obtained following the ISTH-SSC guidelines or the available alternatives. Patients/methodsBlood samples for LA testing from 462 consecutive patients were evaluated for screening, mixing and confirmatory tests. The analysis focused on the interpretation differences between using (1) the in-house cut-off values versus the manufacturer's cut-off values, (2) a normalized ratio calculated using PNP at each run versus the mean of the reference interval, (3) a normalized ratio versus the index of circulating anticoagulant to interpret the mixing step, and (4) a two-step versus three-step procedure. ResultsLA testing outcomes were comparable when using the in-house and manufacturer's cut-off values. More positive dilute Russell's viper venom (DRVV) time results were obtained with the normalized ratio based on PNP than with the mean of the reference interval. Overall, the mixing test results obtained with the normalized ratio and the index of circulating anticoagulant showed a good agreement. Among the 97 DRVV Screen test-positive samples, 33 and 89 were classified as LA-positive with the 3-step and the 2-step procedure, respectively. ConclusionsThe cut-off value used and the way to normalize ratios had a limited impact. Conversely, it is important to understand the mixing test characteristics to maximize its diagnostic potential.

ISOLATION PINOSTROBIN COMPOUND IN TEMU KUNCI (KAEMPFERIA PANDURATA ROXB) RHIZOME

Isolation and identification of Pinostrobin compounds in Temu Kunci Rhizomes (Kaempferia pandurata Roxb) were conducted in this study. The isolation and identification methods used were extraction, crystallization & recrystallization, Thin Layer Chromatography, and (4) Infrared (IR) Testing. The extraction results were followed by crystallization and recrystallization processes. The recrystallization produced a yellow solid isolate. A Thin Layer Chromatography test was carried out to determine the purity of the isolate using the eluent Chloroform : n-hexane of 6:4, Chloroform : Ethylacetate of 7:3. A comparison of the Retention Factor (Rf), and the Rf value of the phinostrobin standard indicates that the positive test sample contained the Pinostrobin compound. The Infrared spectrum indicates that the sample belongs to the flavonol group. It is confirmed from the functional groups of the isolates that are compatible or identical to the functional groups in the pinostrobin compound.

Performance of a Multigene Genomic Classifier in Thyroid Nodules with Suspicious for Malignancy Cytology.

Background: Molecular testing is increasingly used to refine the probability of cancer and assess recurrence risk in thyroid nodules with Bethesda III/IV fine needle aspiration (FNA) cytology. However, limited data exist for Bethesda V (suspicious for malignancy [SFM]) samples. This study evaluated the performance of ThyroSeq v3 (TSv3) in thyroid nodules with SFM cytology. Methods: In this single-institution retrospective cohort study, consecutive thyroid FNA samples diagnosed as SFM with TSv3 testing and known surgical outcome were identified. Clinical, pathology, and molecular findings were reviewed. The TSv3 Cancer Risk Classifier was used to determine molecular risk groups (MRGs). For test-negative cases diagnosed as cancer/noninvasive follicular thyroid neoplasm with papillary-like nuclear features, TSv3 was performed on the resected tumors. Results: Among 128 SFM samples studied, 100 (78.1%) were TSv3 positive, and 28 (21.9%) were negative. The cancer prevalence on surgery was 82.8%. Among test-positive samples, 95% were malignant and 5% benign. Among test-negative samples, 17 (60.7%) were benign and 11 (39.3%) malignant. Overall, TSv3 had a sensitivity of 89.6% (confidence interval; CI 82.4-94.1) and a specificity of 77.3% (CI 56.6-89.9). For a cancer prevalence of 50-75% expected in SFM cytology by the Bethesda system, the negative predictive value was expected to range from 71.2% to 88.1% and the positive predictive value from 79.8% to 92.2%. Among test-positive nodules, 20% were MRG-Low (mostly RAS-like alterations), 66% MRG-Intermediate (mostly BRAF-like alterations), and 14% MRG-High. Among patients with cancer, 65 (61.3%) were American Thyroid Association low risk, 25 (23.6%) intermediate risk, and 6 (5.7%) high risk. During the mean follow-up of 51.2 months (range: <1 to 470 months), 12 (13.0%) patients had disease recurrence, which was more common in MRG-High (54.6%) compared with MRG-Intermediate (9.5%) and MRG-Low (0%) cancers (p < 0.001). Upon reexamining tumors with false-negative results, half of evaluable cases had alterations likely missed due to limiting FNA sampling, and the remainder represented low-risk tumors. Potentially targetable alterations were identified in 10 samples. Conclusions: In this large series of SFM thyroid nodules, TSv3 further improved cancer prediction and detected RAS-like, BRAF-like, high-risk, and potentially targetable alterations, all of which may inform more optimal patient management. MRGs were associated with recurrence-free survival, offering potential preoperative cancer risk stratification.

Seroprevalence of hepatitis b, c and HIV among patients attending a multispecialty hospital: An 8 year old retrospective study

Background: Hepatitis B, Hepatitis C and HIV infection are serious global health problems. Many risk behaviors as well as the routes of transmission for HBV and HCV infections are identical to those for HIV and other sexually transmitted diseases. They are considered as occupational risk for dental professionals and other health care workers of getting HIV, HBV or HCV infection from an infected patient and the potential transmission to susceptible patients from infected dental personnel. Due to lack of knowledge regarding the prevalence of these viral diseases among the local populations, this study was aimed to determine the prevalence of HBV, HCV and HIV by detecting the presence of HBV antigen (HBsAg) and HCV antibodies (HCV-Ab) and HIV antibodies (HIV-Ab) and the relation of their presence with other factors such as gender and age among dental patients visiting a tertiary care teaching hospital in Moradabad city in Uttar Pradesh. Materials and Methods: Case records of a total of 3000 patients were included whose serum was screened using Rapid card diagnostic kits using standard recommended procedure. HIV TRI-DOT for HIV antibodies, HEPACARD for HBsAg and HCV TRI-DOT for HCV antibodies. All rapid test positive samples were further tested by a third-generation Enzyme linked immune sorbent assay (ELISA). Data was analyzed and put for statistical analysis. Results: The overall seroprevalence of the HIV, HBV and HCV increased over the eight year period by approximately 5%. A statistical significant difference in prevalence of HIV, HCV and HBV in male and females was obtained. A high seropositivity was prevalent in the age group of 30-40 years. Conclusion: The sero frequency of HIV, hepatitis B and C was high among patients especially from rural population visiting the tertiary health care hospital that usually go unnoticed leading to cross infection. Thus proper history taking, diagnostic tests and sterilization protocols can minimize and prevent these dreadful blood borne infections from spreading.

Seroprevalence of mycoplasmosis in broiler, layer, and native chickens in Giza, Egypt.

We aimed to investigate Mycoplasma infections among chicken flocks (Ross, Lohmann and native) in Giza, Egypt, using serological tests, including the slide plate agglutination (SPA) test, hemagglutination inhibition (HI) test, and enzyme-linked immunosorbent assay (ELISA). The slide plate agglutination examination, a serological test, indicated the prevalence of Mg and Ms infections of 10.9% and 13.2%, respectively. On 91 SPA test positive serum samples for either Mg or Ms, a passive hemagglutination/hemagglutination inhibition (HI) test was performed. The SPA and HI test findings were found to be comparable. On 90 SPA test positive samples, an ELISA was performed using commercial kits for Mg and Ms serodiagnosis. According to the ELISA data, only 83.33% and 18.88% of SPA test positive samples were confirmed as positive for Ms and Mg infections, respectively. The prevalence increased to 84.44% and 77.77%, respectively, when suspected samples were deemed positive.

A retrospective study on nested PCR detection of syphilis treponemes in clinical samples: PCR detection contributes to the diagnosis of syphilis in patients with seronegative and serodiscrepant results.

Syphilis, caused by Treponema pallidum ssp. pallidum (TPA), is a persisting global health problem. Although syphilis diagnostics relies mainly on serology, serological tests have some limitations, and it is recommended that the final diagnosis be supported by additional tests. The purpose of this study was to analyze the relationship between serology and PCR in syphilis diagnostics. From the year 2004 to May 2019, a total of 941 samples were taken from 833 patients suspected of having syphilis, in Czech Republic. In all these samples, both nested PCR detection of TPA and serology testing were performed. Of the 941 samples, 126 were seronegative, 651 were seropositive, and 164 were serodiscrepant. Among seronegative samples (n = 126), 11 were PCR-positive (8.7%). Among seropositive samples (n = 651; i.e., samples positive for both non-treponemal and treponemal serology tests), 368 samples were PCR-positive (56.5%). The remaining 164 serodiscrepant samples included RPR negative and treponemal serological test-positive samples (n = 154) and a set of 10 RPR-positive samples negative in treponemal serological tests. While the first group revealed 73 PCR-positive samples (47.4%), the second revealed 5 PCR positive samples (50.0%). PCR detection rates were highest in primary syphilis, with lower rates in the secondary and undetermined syphilis stages. As shown here, the nested PCR can improve diagnostics of syphilis, especially in seronegative patients and in patients with discrepant serology.

Semi-quantitative analysis of drugs of abuse in human urine by end-point dilution flow immunochromatographic assay

A novel flow chromatographic immunoassay method using end-point dilution was developed in our laboratory as an alternative to the homogeneous enzyme immunoassay, for low-cost, simple, and fast semi-quantitative analyses of drugs of abuse in human urine. A serial dilution of the positive test sample using rapid test cassettes is continued until reaching the lowest dilution, with a visual detectable colored band at the definite cutoff concentration. The calibration curve of the equivalent dilution volume (end-point titers) vs concentration of the spiked urine sample exhibited excellent linearity with a coefficient of determination R2 of 0.9995 for cannabinoids and 0.9997 for opiates; this indicates that end-point dilution flow chromatographic immunoassay can be used in a semi-quantitative mode for drugs of abuse urine analysis. The developed dilution method exhibits a visual limit of detection (LOD) at the cutoff, and a linear relationship ≥ 50 ng/mL for cannabinoids and ≥ 300 ng/mL for opiates, without an upper limit of detection. The recovery of spiked urine samples is within 98–111% of theoretical values for cannabinoids and 101–110% for opiates. Good correlation was obtained between end-point dilution flow chromatographic immunoassays and homogenous immunoassays with a Thermo Scientific Indiko autoanalyzer for cannabis abuse specimens.

Serological and Molecular Epidemiology of Human Brucellosis in Mymensingh region Bangladesh

Brucellosis is a major Bacterial Zoonotic disease worldwide. More than 500,000 new cases are reported globally every year with the annual incidence rates varying widely from &lt;2 to &gt;500 per 1000,000 population among different region of the world. This cross sectional descriptive study was carried out in the department of microbiology, Mymensingh medical college, Mymensingh, Bangladesh from 1st January to 31 December 2017, on total 600 patients of PUO with or without occupational exposure. Blood was taken as sample, serum was separated and screening test was done by Brucella specific latex agglutination test from all collected samples. A Titer of ≥ 1:160 was taken as positive. ICT, PCR and real time PCR were done from all screening positive samples. Among the study population 65.83% (395/600) were male and 34.17% (205/600) were female. The sero prevalence of Human Brucellosis was found 13.33% (40/300) and 5% (15/300), respectively in risk and non risk group of population. Out of 55 Brucella specific latex agglutination test positive samples 27.27% (15/55) were ICT positive, 5.45% (3/55) were PCR positive and 3.64% (2/55) were real time PCR positive. No ICT, PCR or Real time PCR cases were found from sero negative samples. Among the ICT positive cases 86.67% (13/15) from risk group and 13.33% (2/15) from non risk group of study population. Among the 3 PCR positive cases 13.33% (2/15) were from ICT positive cases and 2.5 % (1/40) from ICT negative cases. All PCR and Real time PCR positive cases were found in risk group of study population. No reliable data for Human Brucellosis is available in our country. However the present study revealed that a considerable number of Human Brucellosis is present in risk group as well as non risk group of population in both rural and urban area in Mymensingh district of Bangladesh. In our country we use only Brucella specific latex agglutination test for diagnosis of human Brucellosis. It is a non specific test and gives many false positive results. So it is necessary to introduce newer tests with higher sensitivity and specificity which will help to diagnose the disease rapidly and more accurately.&#x0D; Bangladesh J Med Microbiol 2020; 14 (2): 19-24

Serological evaluation of Neospora caninum in pregnant women treated at referral center for prenatal screening in Mato Grosso do Sul, Brazil.

Neospora caninum is an obligate intracellular protozoan with canids (Canis domesticus, Canis lupus dingo, Canis latrans, Canis lupus) as its definitive hosts. The objective of this study was to detect anti-N. caninum antibodies in pregnant women seen at referral center for prenatal screening in the state of state Mato Grosso do Sul, Brazil. A total of 188 serum samples from pregnant women provided by the Instituto de Pesquisa, Ensino e Diagnósticos da APAE de Campo Grande (IPED/ APAE) were subjected to IFA test and western blot analysis. The samples were divided into three groups: 23/99 samples from the seropositive group for toxoplasmosis were positive for anti-N. caninum IgG antibodies, and 9/99 positive for IgM; in the HIV group, 7/33 were positive for IgG; and in the HIV+toxoplasmosis group, 13/56 were positive for IgG and two positive for IgM. The seropositivity for IgG was assessed by western blot by testing 43 IFA test positive samples using rNcSRS2 (Nc-p43) as antigen. The serological results of the present study suggest that exposure of these pregnant women to the parasite N. caninum and presence of IgM antibodies are indicative of recent infection. Further studies are needed to establish the possibility of active infection.

Homogeneous Differential Magnetic Assay.

Assays are widely used for detection of various targets, including pathogens, drugs, and toxins. Homogeneous assays are promising for the realization of point-of-care diagnostics as they do not require separation, immobilization, or washing steps. For low concentrations of target molecules, the speed and sensitivity of homogeneous assays have hitherto been limited by slow binding kinetics, time-consuming amplification steps, and the presence of a high background signal. Here, we present a homogeneous differential magnetic assay that utilizes a differential magnetic readout that eliminates previous limitations of homogeneous assays. The assay uses a gradiometer sensor configuration combined with precise microfluidic sample handling. This enables simultaneous differential measurement of a positive test sample containing a synthesized Vibrio cholerae target and a negative control sample, which reduces the background signal and increases the readout speed. Very low concentrations of targets down to femtomolar levels are thus detectable without any additional amplification of the number of targets. Our homogeneous differential magnetic assay method opens new possibilities for rapid and highly sensitive diagnostics at the point of care.

CLINICAL SPECTRUM OF SCRUB TYPHUS IN A TERTIARY CARE HOSPITAL AT EASTERN INDIA

Objective: Our hospital, tertiary care hospital in the capital of the state of Odisha, had been witnessing pyrexia of unknown origin, associated with breathlessness, renal, and liver impairment, which did not respond to high antibiotics but to doxycycline; therefore, the present study was undertaken to identify whether scrub typhus is the etiological agent, and thereafter, their characteristic features were further evaluated as an effort in supporting its diagnoses and treating patients accordingly.Methods: A total of 65 adult patients (age &gt;15 years) admitted with pyrexia between April 2015 and October 2017 were evaluated. Immunoglobulin M (IgM) scrub typhus test was done in all these patients. IgM scrub typhus test positive samples were included in the study and various clinical parameters analyzed.Results: Of the 65 patients included in the study, all were found to be positive for IgM antibodies against Orientia tsutsugamushi. The cases were seen mainly in the months between September and November. The common symptoms found were fever, myalgia, breathlessness, rash, and abdominal pain and rarely altered sensorium. The diagnostic features like eschar were found in 23% patients. Nearly, two-thirds of patients had fever more than 7 days and myalgia (76.92%), headache (58.46%). The most common complications were renal failure (20%) followed by pneumonia (10.76%). Laboratory findings of high C-reacting protein (89.23%) and leukocytosis are found in 35.38%.Conclusion: Our results showed that scrub typhus should be considered in the differential diagnosis of pyrexia of unknown origin associated with breathlessness, myalgia, rash, gastrointestinal symptoms, hepatorenal syndrome, or acute respiratory distress syndrome. Empirical treatment with doxycycline may be given in the cases with strong suspicion of scrub typhus.

Bayesian estimation of true prevalence, sensitivity and specificity of three diagnostic tests for detection of Escherichia coli O157 in cattle feces

Cattle are a reservoir for Escherichia coli O157 and they shed the pathogen in their feces. Fecal contaminants on the hides can be transferred onto carcasses during processing at slaughter plants, thereby serving as a source of foodborne infection in humans. The detection of E. coli O157 in cattle feces is based on culture, immunological, and molecular methods We evaluated the diagnostic sensitivity and specificity of one culture- and two PCR-based tests for the detection of E. coli O157 in cattle feces, and its true prevalence using a Bayesian implementation of latent class models. A total of 576 fecal samples were collected from the floor of pens of finishing feedlot cattle in the central United States during summer 2013. Samples were enriched and subjected to detection of E. coli O157 by culture (immunomagnetic separation, plating on a selective medium, latex agglutination, and indole testing), conventional PCR (cPCR), and multiplex quantitative PCR (mqPCR). The statistical models assumed conditional dependence of the PCR tests and high specificity for culture (mode=99%; 5th percentile=97%). Prior estimates of test parameters were elicited from three experts. Estimated posterior sensitivity (posterior median and 95% highest posterior density intervals) of culture, cPCR, and mqPCR was 49.1% (44.8–53.4%), 59.7% (55.3–63.9%), and 97.3% (95.1–99.0%), respectively. Estimated posterior specificity of culture, cPCR, and mqPCR were 98.7% (96.8–99.8%), 94.1% (87.4–99.1%), and 94.8% (84.1–99.9%), respectively. True prevalence was estimated at 91.3% (88.1–94.2%). There was evidence of a weak conditional dependence between cPCR and mqPCR amongst test positive samples, but no evidence of conditional dependence amongst test negative samples. Sensitivity analyses showed that overall our posterior inference was rather robust to the choice of priors, except for inference on specificity of mqPCR, which was estimated with considerable uncertainty. Our study evaluates performance of three diagnostic tests for detection of E. coli O157 in feces of feedlot cattle which is important for quantifying true fecal prevalence and adjusting for test error in risk modeling.

Bordetella bronchiseptica infection

ObjectiveTo collect data of all patients admitted to hospital with a positive test to Bordetella bronchiseptica between 2001 and 2015. MethodsWe performed a retrospective monocentric study of all hospitalized patients over the past 15 years with a positive test to B. bronchiseptica. ResultsNine patients were included between 2001 and 2015; two presented with infectious relapses, i.e. a total of 14 positive test samples were observed. Age, induced immunodeficiency, and preexisting respiratory illnesses are risk factors. All patients showed symptoms at sample collection and the infection was exclusively respiratory. The diagnosis was obtained through a cytobacteriological test of sputum, bronchial aspiration, or bronchial fibroscopy with a bronchoalveolar lavage. The drug susceptibility test revealed a natural resistance to cephalosporins including ceftazidime, monobactam, and fosfomycin. There were cases of resistance to penicillin A and to the trimethoprim/sulfamethoxazole association. The classically used antibiotic treatment for community-acquired pneumonia is based on probability and may thus fail. Four patients died. The duration and nature of the antibiotics to use have not been codified. ConclusionB. bronchiseptica infection mainly affects the elderly. All patients should be treated, regardless of the importance of the inoculum, and all infected animals should be treated.