Positive Polymerase Chain Reaction Results Research Articles

To the question regarding accuracy of COVID-2019 laboratory diagnostics

Issues of accuracy (sensitivity and specificity) of PCR-analysis depending on features of performing preanalytical and analytical stages of laboratory diagnostics of COVID-19, as well as comparing PCR and lung computed tomography (CT) results have been analyzed in the study. Currently, a molecular genetic test based on polymerase chain reaction (PCR) is used for diagnostics of a new coronavirus infection (COVID-19). As of November 1, 2020, more than 750 million PCR tests have been conducted globally. Evidence accumulated by now allows to estimate diagnostic sensitivity and specificity of the SARS-CoV-2-specific PCR as high as 82—91% and 99—100%, respectively. In addition, increased PCR sensitivity may be noted upon performing repeated testing of the upper respiratory tract samples comprising 82.2% during the primary analysis that was further elevated up to 90.6% after two consecutive tests. A whole set of factors affect the PCR accuracy. In particular, false negative data might result from insufficient amount of virus-coupled genetic material in the sample, timeframe and mistakes made upon selecting biological samples. It was found that SARS-CoV-2 virus RNA was detected at the maximum diagnostic sensitivity in the upper respiratory tract 1—3 days before the onset of symptoms and sustained within the 5—6 days after disease onset. Such period of time is associated with the peak risk of SARS-CoV-2 transmission. On week 2 after disease onset, there have been noted elevated rate of detecting viral RNA in bronchopulmonary samples. The duration of detecting virus-related markers (including those found in the absence of viable virus forms) correlates with disease severity and may last for as long as 1—2 months. Another real-world issue related to PCR analysis is posed by an opportunity of obtaining false positive data, which solution requires high level organized laboratory research, especially in case large-scale studies. Upon that, it is worth noting that positive PCR results may account for detecting solely certain RNA-related fragments present in any sample, rather than a viable virus. It was noted that PCR in comparison to CT analysis demonstrates higher specificity, but does not allow to distinguish pneumonia caused by SARS-CoV-2 from pneumonia caused by other etiological agents (up to 25% false positive results). However, the diagnostic CT sensitivity was 97.2% that exceeds such parameter for PCR by 10—15%. It was concluded that the approach combining use of both PCR and CT by taking into account their own features as well as factors affecting the accuracy of the data obtained, allows us to correctly interpret the diagnostical results.

Diagnostic properties of case definitions of suspected COVID-19 in Chile, 2020Características diagnósticas das definições de caso suspeito de COVID-19 no Chile, 2020

RESUMENObjetivo.Comparar las propiedades diagnósticas de cinco definiciones de caso sospechoso de COVID-19 utilizadas o propuestas en Chile durante los primeros ocho meses de la pandemia.Métodos.Se analizaron las propiedades diagnósticas (sensibilidad, especificidad, y valores predictivos positivo y negativo) de tres definiciones de caso sospechoso de COVID-19 utilizadas en Chile entre marzo y octubre del 2020, y dos propuestas de definición alternativas. La muestra fue de 2 019 personas con resultados conocidos a la prueba de la reacción en cadena de la polimerasa (PCR) para SARS-CoV-2. Para elaborar el criterio 5 se aplicó una regresión logística escalonada (stepwise) optimizando los valores de sensibilidad y especificidad. Se exploró la asociación de variables demográficas, síntomas y signos con la positividad a la PCR mediante regresión logística multifactorial. Se analizaron diferentes escenarios de positividad y se compararon las curvas ROC.Resultados.La presencia de anosmia (OR = 8,00; IC95%: 5,34–11,99) y fiebre (OR = 2,15; IC95%: 1,28–3,59) y el haber tenido contacto estrecho previo con una persona enferma de COVID-19 (OR = 2,89; IC95%: 2,16–3,87) se asociaron con un resultado positivo de la PCR. Según el análisis de las curvas ROC, el criterio 5 tuvo la mayor capacidad de discriminación, aunque sin diferencias significativas con los otros cuatro criterios.Conclusiones.El criterio 5 —basado en la anosmia, el contacto estrecho con personas enfermas de COVID-19 y la fiebre como elementos únicos suficientes— tuvo la mayor sensibilidad para identificar los casos sospechosos de COVID-19, aspecto fundamental para controlar la propagación de la pandemia.

Detection of Schistosoma mansoni DNA using polymerase chain reaction from serum and dried blood spot card samples of an adult population in North-western Tanzania

BackgroundReal-time polymerase chain reaction (PCR) is a sensitive and specific method for diagnosing schistosomiasis. However, this method should be performed in a laboratory, usually located distant from the sample collection site. Therefore, it is important to have fast sampling preservation methods, which allow simple transport prior to DNA extraction and amplification. The aim of this study was to verify if blood samples applied to filter paper are suitable for analysis of Schistosoma mansoni DNA by real-time PCR.MethodsA cross-sectional study was conducted among 100 study participants aged 17 to 70 years in a fishing village on the southern shore of Lake Victoria, Tanzania. Serum samples and ethylenediaminetetraacetic acid (EDTA)-anticoagulated whole blood for preparation of dried blood spots (DBS) were collected to test for Schistosoma mansoni infection by real-time PCR. A combined diagnostic reference of positive results of serum-based real-time PCR and the Kato-Katz (KK) method was used for analysis. Sensitivity and negative predictive value (NPV) were calculated. The Wilcoxon signed-rank test was chosen to compare the mean cycle threshold (Ct) values from serum and DBS.ResultsAccording to the reference, 92.5% S. mansoni positive samples were determined. The serum-based real-time PCR performed excellently with 95.4% sensitivity, whereas the DBS-based real-time PCR showed a low sensitivity (45.4%). The Ct-values were significantly higher in DBS (median: 37.3) than in serum samples (median: 27.5, P < 0.001), reflecting a lower parasite-specific DNA load on the filter cards. With increasing egg counts, an increase in sensitivity was observed for all methods. The POC-CCA test and the serum-based real-time PCR showed a sensitivity of 100% for medium and severe infections. The DBS real-time PCR showed a sensitivity of only 85.7% even for severe infections.ConclusionsDBS-based real-time PCR did not provide good results in our study and therefore should not be recommended or must be tested concerning temperature of storage, storage duration, use of different filter papers and extraction methods before it is used in future studies. In contrast, our results showed that the POC-CCA test is a sensitive and precise test for detecting S. mansoni infections .

Significance of a polymerase chain reaction method in the detection of Clostridioides difficile.

RESUMENObjetivosClostridioides difficile (CD) es la causa más frecuente de diarrea nosocomial. Se han propuesto algoritmos para mejorar el diagnóstico de la infección, basados en la realización de un método rápido que detecte glutamato deshidrogenasa (GDH) y/o toxinas A/B, seguido de una prueba confirmatoria (cultivo toxigénico, prueba de citotoxicidad, técnicas de biología molecular). Evaluamos un algoritmo diagnóstico para la detección de CD utilizando un test inmunocromatográfico y una prueba de reacción en cadena de la polimerasa (PCR).Material y métodosSe realizaron dos pasos: 1) Un enzimoinmunoensayo rápido de membrana que detecta simultáneamente GDH y toxinas de CD (C.diff QUIK CHEK complete). Las muestras positivas frente a ambos se consideraron positivas; 2) A todas las muestras que fueron positivas sólo para GDH o toxina se les realizó un ensayo de PCR en tiempo real que detecta el gen de la toxina B (tcdB) (BD MAX Cdiff). Se consideraron positivas todas las muestras PCR positivas.ResultadosSe realizaron 2.138 determinaciones. 139 fueron positivas en GDH y toxinas, 148 sólo en GDH, y 12 sólo en toxinas. De las 160 dudosas, 117 fueron positivas por PCR (107/148 GDH+ y 10/12 toxinas+).ConclusionesLa PCR ha detectado 117 positivos más (un 73,1% de las muestras dudosas). Tradicionalmente los resultados toxinas+/GDH- se consideran falsos positivos. Creemos que la detección sumada de toxinas en el inmunoensayo y del gen tcdB en una misma muestra sería indicativa de su presencia real, y el resultado negativo de la GDH podría deberse a un falso negativo.

Increase in Detection of Respiratory Syncytial Virus Among Older Adults in Arizona : An Association With Changes in Testing Practices.

Respiratory syncytial virus (RSV) is a common cause of respiratory illness, health care visits, and hospitalizations. Arizona, which began conducting laboratory surveillance in 2004, has noted an increase in RSV cases (defined as a laboratory-positive result) among adults aged ≥65, concurrent with increasing reports from polymerase chain reaction (PCR) testing. We assessed whether the shift in the age distribution of reported RSV cases resulted from a change in RSV testing practices. We used data on laboratory-confirmed RSV cases reported during 2013-2017 from the statewide surveillance system to assess the frequency of test types (rapid antigen, immunofluorescence assay, PCR, and viral culture) by age groups across RSV seasons, and we used logistic regression to estimate changes in odds of receiving a PCR test. We used statewide emergency department hospital discharge data for the same period to assess testing practices regardless of test result. The overall proportion of PCR tests among RSV cases increased significantly, from 22% in 2013 to 55% in 2017 (P < .001). The percentage of RSV cases among adults aged ≥65 also increased significantly, from 4% in 2013 to 11% in 2017 (P < .001) of RSV cases. Adults aged ≥65 had more than 8 times the odds of positive PCR results than children aged <5, both in crude (odds ratio [OR] = 8.8; 95% CI, 7.6-10.2) and season-adjusted (adjusted OR = 8.1; 95% CI, 7.0-9.5) models. Hospital discharge data corroborated increased RSV PCR usage from 2013 to 2017. Increasing RSV rates among adults aged ≥65 are likely a result of changes in testing practices. This age group may need more targeted intervention and future vaccination.

COVID-19 Testing Results by HIV Status, March-July 2020, Chicago, USA.

The role of HIV in coronavirus disease 2019 acquisition is not yet understood. Among 1862 patients, including 349 people with HIV—with most of these being virally suppressed and 308 having recently used pre-exposure prophylaxis—we compared rates of positive polymerase chain reaction results. Positivity was higher among people with HIV (10.6%) compared with HIV-negative patients (7.1%) but was not significant in adjusted models.

Molecular and serological detection and of Toxoplasma gondii in small ruminants of southwest Iran and the potential risks for consumers.

Toxoplasmosis is one of the most important zoonotic diseases with serious health risks for humans, especially for immunodeficient patients, and can lead to abortion in pregnant women worldwide. The oral uptake of sporulated oocysts and/or consumption of undercooked/raw meat of animals infected with Toxoplasma gondii can infect other animals and humans. Heart, liver, and meat tissues of 150 sheep and 150 goats from a slaughterhouse in Ahvaz, Iran, were collected during autumn 2018 and analyzed via polymerase chain reaction (PCR) to detect parasitic DNA in the animal tissues. Moreover, antibodies against T. gondii of 150 sera samples were detected as the targets by in-house enzyme-linked immunosorbent assay (in-house ELISA). A total of 26 (17.3%), 33 (22%), and 48 (32%) of liver, meat, and heart samples in sheep, and a total of 24 (16%), 26 (17.3%), and 36 (24%) of liver, meat, and heart samples in goats, respectively, showed positive PCR results. Besides, the ELISA evaluation of sera samples from 150 sheep and 150 goats resulted in 26 (13.3%) and 16 (10.6%) positive cases, respectively. A significant difference was also found between PCR-positive heart samples and ELISA-positive sera samples of both animal species (p < 0.05), but no significant difference existed between PCR-positive liver samples and ELISA-positive sera samples of both species (p > 0.05). The results of this study confirm the presence of T. gondii in sheep and goats’ consumable organs, highlighting the need to avoid consuming raw or uncooked organs of these animal species to prevent human infection with T. gondii.Electronic supplementary materialThe online version of this article (10.1007/s00003-020-01306-w) contains supplementary material, which is available to authorized users.

The diagnostic performance of chest computed tomography scanning in the diagnosis of coronavirus disease 2019 compared to polymerase chain reaction: A retrospective study of 1240 cases from Tripoli University Hospital, Libya

OBJECTIVE: The increasing prevalence of suspected cases of coronavirus disease 2019 (COVID-19) presenting to emergency departments (EDs) requires a rapid and reliable triaging tool. The diagnostic performance of chest computed tomography (CT) has yet to be validated for triaging cases in the ED. We aimed to assess the diagnostic performance of chest CT compared to GeneXpert Xpress Xpert severe acute respiratory syndrome coronavirus 2 test in rapidly diagnosing COVID-19 among patients with respiratory symptoms presenting to the ED.MATERIALS AND METHODS: This was a retrospective, single-center study at Tripoli University Hospital including cases with respiratory symptoms who underwent chest CT as well as polymerase chain reaction (PCR) testing for suspected COVID-19 between May 18 and August 18, 2020.RESULTS: A total of 1240 cases were included, among whom 570 had radiologically evident COVID-19 on chest CT (46%). Five hundred and sixty-five cases had positive PCR results (45.6%), of whom 557 had radiologically evident COVID-19 on chest CT (97.7%). The calculated accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 98%, 98.5%, 98%, 97.7%, and 98.8%, respectively, in relation to the PCR results.CONCLUSION: During the current pandemic, chest CT is a quick and reliable diagnostic tool for COVID-19 in the ED.

Genetic and parasitological identification of Trypanosoma evansi infecting cattle in South Sulawesi, Indonesia.

Background and Aim:Sulawesi is an Indonesian island located within the Wallacea region that contains a distinctive mix of Asian and Australasian species. This distinctiveness extends to parasites, including Trypanosoma evansi, the cause of surra. Surra has non-specific clinical signs such as anemia, anorexia, weight loss, drop in milk production, and reproductive disorders which cause economic losses. Due to the trade of livestock, surra has spread in Indonesia from one island to another. The aim of this study was to investigate the trypanosomes infecting cattle in South Sulawesi, using internal transcribed spacer (ITS2) ribosomal DNA (rDNA) sequencing.Materials and Methods:A total of 100 whole blood samples were collected from cattle in Makassar, South Sulawesi Province, Indonesia. All samples were tested using conventional parasitological methods (CPT), namely, thin blood smear, buffy coat smears, and polymerase chain reaction (PCR) testing. Positive PCR results were sequenced and phylogenetically analyzed.Results:Only one of the 100 samples was found to be positive with microscopic observation; however, PCR analysis revealed that 3% (3/100) of samples were positive. Sequencing identified the positive samples as T. evansi, China isolate (KU552344), with a homology of 99%. Two out of three sequences showed variations in ITS2 region.Conclusion:Based on CPT and molecular analysis, T. evansi isolates from infected cattle in South Sulawesi demonstrate genetic diversity of ITS2 sequences.

Chest X-Ray in Coronavirus Disease 2019 (COVID-19) Infection: Findings and Correlation with Clinical Outcome at Level-3 Nepalgunj Medical College and Teaching Hospital Kohalpur

Introduction: At the end of 2019 a novel virus, named SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2), expanded globally from China. A new coronavirus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), was identified as the cause of this outbreak of viral pneumonia that causes coronavirus disease 2019 (COVID-19). Aims: The aim of this study is to find out the chest radiological features of corona virus disease patients and correlate them with clinical outcome. Methods: This is a Hospital based study involving patients with clinical-epidemiological aspect of all reverse transcription polymerase chain reaction (RT-PCR) corona virus disease (COVID-19) positive patients, who performed Chest X-Rays at the emergency department of Nepalgunj Medical College, Teaching Hospital from March to June, 2020. All patients performed reverse transcription polymerase chain reaction from nasopharyngeal and throat swab, Chest X-Ray at the Emergency Department and clinical-epidemiological data. Results: Patients with a reverse transcription polymerase chain reaction positive results for corona virus disease infection were 32 out of these, 22 were females (68.75%) and 10 males (31.25%), with a mean age of 40.78 years (range 20–74 years). Only 2 Chest X-Rays were negative for radiological thoracic involvement (6.25%). The following alterations were more commonly observed among 30 patients: 18 patients with lung consolidations (56.25%), 19 (59.37%) with Ground Glass Opacities, 7 (21.87%) with nodules and 21 (65.6%) with reticular–nodular opacities. Patients with consolidations and Ground Glass Opacities coexisting in the same radiography were 34.37% of total. In reverse transcription polymerase chain reaction positive patients, we found also signs nonspecific for corona virus disease pneumonia as hilar or vascular congestion (37.5%), cardiomegaly (28.12%), pleural effusion (15.6%) and pneumothorax (3.12%). Peripheral (56.25%) and lower zone distribution (56.25%) were the most common predominance. Bilateral involvement (68.75%) was most frequent than unilateral one. Given the results, baseline Chest X-Rays sensitivity in our experience is about 65.62%. Conclusion: In this study, COVID-19 CXRs generally manifested a spectrum of pure ground glass, mixed ground glass opacities to consolidation in bilateral peripheral middle and lower lung zones. BSTI CXR reporting classification of COVID-19 is valid and sensitive in our patients with addition of middle zonal involvement in classical COVID-19 criteria as opposed to just lower zone involvement.

Evaluation of the Xiamen AmonMed Biotechnology rapid diagnostic test COVID-19 IgM/IgG test kit (Colloidal gold).

IntroductionTo efficiently monitor the COVID-19 pandemic for surveillance purposes, reliable serological rapid diagnostic tests (RDTs) are desirable for settings where well-established high-throughput bench-top solutions are not available. Here, we have evaluated such an RDT.MethodsWe have assessed the Xiamen AmonMed Biotechnology COVID-19 IgM/IgG test kit (Colloidal gold) and the EUROIMMUN benchtop assay with serum samples from patients with polymerase chain reaction (PCR)-confirmed COVID-19 disease. Samples from patients with Epstein-Barr-virus (EBV) infection and blood donors were used for specificity testing.ResultsFor the colloid gold rapid test and the EUROIMMUN assay, the study indicated overall sensitivity of 15.2% and 67.4%, respectively, while specificity of 99.0% and 97.9% with the blood donor sera, as well as 100% and 96.8% with the EBV-patients, were observed, respectively. An association of the time period between positive PCR results and serum acquisition with serological test positivity could be observed for the immunologlobulin G subclass of the EUROIMMUN assay only.ConclusionsIn spite of acceptable specificity of the assessed RDT, the detected poor sensitivity leaves room for improvement. The test results remain difficult to interpret and therefore the RDT can currently not be recommended for routine diagnostic or surveillance use.

An improved pre-culture procedure for the detection of Salmonella in frozen chicken meat by duplex polymerase chain reaction

An improved 18-hour pre-culture procedure coupling with duplex polymerase chain reaction (PCR) method capable of detecting Salmonella in frozen chicken meat is herein reported. Two pairs of primers (TS5/TS11 and S18/S19) were used for the PCR method. Positive PCR results were obtained after the 18-hour preculture (6 h in lactose broth at 37℃ followed by 12 h in Rappaport-Vassiliadis broth at 42℃) for spiked raw and irradiated meats with or without freezing treatment. The applicability of this improved procedure was tested in 50 retail frozen and 50 non-frozen chicken drumstick samples, and the results were compared with those obtained with the BAM standard culture method. No significant difference was found (p≧0.05) between these two methods.

Comparison of Two Real-time Polymerase Chain Reaction Assays for the Detection of Severe Acute Respiratory Syndrome-CoV-2 from Combined Nasopharyngeal-Throat Swabs

AbstractContext: In the absence of effective treatment or vaccine, the current strategy for the prevention of further transmission of severe acute respiratory syndrome (SARS) CoV-2 (COVID-19) infection is early diagnosis and isolation of cases. The diagnosis of SARS-CoV-2 is done by detecting viral RNA in the nasopharyngeal and throat swabs by real-time polymerase chain reaction (PCR). Many commercial assays are now available for performing the PCR assay. Aims: The aim was to evaluate the performance of the SD Biosensor nCoV real-time detection kit with the real-time PCR kit provided by the Indian Council of Medical Research-National Institute of Virology (ICMR-NIV), Pune (NIV Protocol). Subjects and Methods: A total of 253 pairs of nasopharyngeal-oropharyngeal swabs combined in a single viral transport medium were tested for viral RNA by both the protocols. The sensitivity and specificity of the SD Biosensor were calculated considering the ICMR-NIV kit as the gold standard. Matched pairs of recorded cycle threshold values (Ct values) were compared by Pearson’s correlation coefficient. Results: Concordant COVID-19 negative and positive PCR results were reported for 113 and 77 samples, respectively. The SD Biosensor kit additionally detected 62 cases, which were found negative by the NIV protocol. In all discordant positive results by the SD Biosensor kit, the average Ct values were higher than the concordant positive results. A total of forty samples tested positive for E gene by SD Biosensor and having Ct values <25 had 100% concordance with NIV protocol results and 39 samples tested positive for E gene by SD Biosensor having Ct value >32 were all found negative by the NIV protocol. Conclusions: The results highlight the need for careful evaluation of commercial kits before being deployed for screening of COVID-19 infections.

Contributions of molecular techniques in the chronic phase of Chagas disease in the absence of treatment

IntroductionThe chronic phase of Chagas disease (CD) is characterised by a low and intermittent parasitaemia. The Polymerase Chain Reaction (PCR) presents a variable sensitivity in this stage limiting its use as a diagnostic tool. Despite this, the use of PCR in untreated patients can provide information on the parasite behavior and its presence in peripheral blood. MethodsA timely real-time PCR determination was performed on a cohort of 495 untreated chronic CD patients. Also, a subcohort of 29 patients was followed-up by serial real-time PCR during a period from 8 to 12 months in which they could not have access to the treatment due to lack of supply. ResultsThe positive percentage of real-time PCR in our series was 42%. Nevertheless, real-time PCR positive results were significantly higher in patients with five years or less of residence in Spain (P = .041). The detection of DNA was not related to the existence of cardiac and/or gastrointestinal abnormalities.In the follow-up subgroup, real-time PCR was consistently positive in 13.8% of patients, consistently negative in 31%, and intermittent in 55.2%. ConclusionsThe different real-time PCR results regarding the time of residence suggests the possible relationship of external factors in the parasite presence in peripheral blood. On the other hand, specific host factors may be involved in the behavior of parasitaemia over time.

Duration of viral shedding in asymptomatic or mild cases of novel coronavirus disease 2019 (COVID-19) from a cruise ship: A single-hospital experience in Tokyo, Japan

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the cause of novel coronavirus disease 2019 (COVID-19), was first reported in Wuhan, China, and now has spread across the world as a global pandemic. The propagation from asymptomatic polymerase chain reaction (PCR)-positive individuals represents a complicating factor in the efforts to control the COVID-19 pandemic. We examined the course of PCR assays and the duration of viral shedding in 23 asymptomatic or mild COVID-19 patients from the cruise ship who were admitted to our hospital. Among these 23 cases, the median duration of viral shedding was 19 days (range, 6–37 days) from initial viral detection. Eight cases (35%) had another positive PCR result after testing negative once. Although the duration of viral shedding was approximately three weeks, the infectivity and transmissibility period from asymptomatic and mild COVID-19 cases is unclear. Further studies are needed to determine how long such asymptomatic and mild COVID-19 cases have infectivity.

Fatal COVID-19 in a Patient with End-Stage Liver Disease Wait-Listed for Liver Transplantation: An Evidence-Based Review of COVID-19 Screening Modalities Prior to Transplant.

Fatal COVID-19 in a Patient with End-Stage Liver Disease Wait-Listed for Liver Transplantation: An Evidence-Based Review of COVID-19 Screening Modalities Prior to Transplant.

Clinical utility and cost-effectiveness of bacterial 16S rRNA and targeted PCR based diagnostic testing in a UK microbiology laboratory network

16S ribosomal-ribonucleic acid polymerase chain reaction (PCR) and targeted PCR aid microbiological diagnosis in culture-negative clinical samples. Despite routine clinical use, there remains a paucity of data on their effectiveness across a variety of clinical sample types, and cost-effectiveness. In this 4 year multicentre retrospective observational study, all clinical samples referred for 16S PCR and/or targeted PCR from a laboratory network serving seven London hospitals were identified. Laboratory, clinical, prescribing, and economic variables were analysed. 78/607 samples were 16S PCR positive; pus samples were most frequently positive (29/84; p < 0.0001), and CSF least (8/149; p = 0.003). 210/607 samples had targeted PCR (361 targets requested across 23 organisms) with 43/361 positive; respiratory samples (13/37; p = 0.01) had the highest detection rate. Molecular diagnostics provided a supportive microbiological diagnosis for 21 patients and a new diagnosis for 58. 14/91 patients with prescribing information available and a positive PCR result had antimicrobial de-escalation. For culture-negative samples, mean cost-per-positive 16S PCR result was £568.37 and £292.84 for targeted PCR, equating to £4041.76 and £1506.03 respectively for one prescription change. 16S PCR is more expensive than targeted PCR, with both assisting in microbiological diagnosis but uncommonly enabling antimicrobial change. Rigorous referral pathways for molecular tests may result in significant fiscal savings.

Appropriately Selected Nerve in Suspected Leprous Neuropathy Yields High Positive Results for Mycobacterium leprae DNA by Polymerase Chain Reaction Method.

Identification of Mycobacterium leprae DNA by polymerase chain reaction (PCR) is a reliable and an affordable method to confirm leprosy. DNA from 87 nerve samples (61 from paraffin blocks and 26 fresh samples) was extracted. Mycobacterium leprae DNA was amplified by PCR from 80/87 (92%) specimens. Patients were seen over a period of 11 years (2007-2019), and leprosy was diagnosed based on clinical and characteristic histopathology findings. The clinical diagnostic possibilities were as follows: leprous neuropathy in 73/80 (91.3%), mononeuritis multiplex of unknown etiology in four (5.0%), vasculitic neuropathy in two (2.5%), and distal symmetric sensory motor neuropathy in one (1.3%). The biopsied nerves were as follows: superficial radial = 34 (42.6%), dorsal cutaneous branch of ulnar = 19 (23.8%), sural = 18 (22.5%), and superficial peroneal = 9 (11.3%), and corresponding neurological deficits were recorded in 77 (96.3%) cases. The histopathological diagnoses in total group were as follows: (borderline tuberculoid (BT) = 52, tuberculoid (TT) = 8, borderline lepromatous (BL) = 8, borderline borderline (BB) = 3, nonspecific inflammation = 3, healed/fibrosed = 4, and axonopathy = 2). Acid fast bacilli (AFB) was demonstrated in 11 (13.7%) samples. For comparison, 31 clinically and histopathologically defined non-leprous disease control nerves (inherited neuropathy = 20, vasculitis = 8, and nutritional neuropathy = 3) subjected to PCR were negative for M. leprae DNA. In most instances, there are multiple thickened peripheral nerves in suspected cases of leprosy, but neurological deficits pertaining to the thickened nerve are not as widespread. The current findings emphasize the importance of selecting the most appropriate nerve for biopsy to obtain a positive PCR result. We infer that clinical, histopathological, and PCR tests complement each other to help achieve a definitive diagnosis of leprosy particularly in pure neuritic leprosy and in leprous neuropathy with negative skin smears/biopsy.

Tuberculous Mastitis in Females of South Punjab: A Clinicopathological Analysis of Ten Years from Pakistan

&lt;p&gt;&lt;strong&gt;Background and Objective:&lt;/strong&gt; Extrapulmonary tuberculosis occurring in breast is a rare disorder in West but is still present in developing nations where tuberculosis is endemic. Tuberculous Mastitis (TM) is difficult to diagnose as it has vague clinical symptoms and insufficient radiological findings. The objective of this study was to determine the frequency of tuberculous mastitis by accessible modalities for early diagnosis.&lt;br /&gt;&lt;strong&gt;Methods:&lt;/strong&gt; After the Institutional Ethical Board approvals, Pathology laboratory archives and medical records of 5000 patients from Ibn-e-Sina Hospital Research Institute, Multan and Multi Test Laboratory, were retrieved from the year 2008 to 2018. A retrospective analysis of fine needle aspiration cytology (FNAC) results of patients who presented with breast lumps was carried out. The interpretation of cytological findings and Ziehl Neelsen stained smears was carried out by cytopathologists and microbiologists respectively. Mycobacterium DNA was detected using polymerase chain reaction (PCR) in selected cases.&lt;br /&gt;&lt;strong&gt;Results&lt;/strong&gt;: Out of 5000 patients, tuberculosis was diagnosed in 264 (5.28%) cases on FNAC. Acid fast bacilli (AFB) positive smears were found in 79.5%patients while 20.45% cases were AFB negative. Among AFB negative smears, 38 cases were further analyzed by PCR, among which 32 (84.2%) cases showed PCR positive results for TM. An increased frequency of TM among all inflammatory breast lesions from 18% in 2008 to 47.19% in 2018 was observed.&lt;br /&gt;&lt;strong&gt;Conclusion: &lt;/strong&gt;Tuberculous Mastitis is an uncommon form of extra-pulmonary tuberculosis. It has non- specific clinical, radiological and varied histological findings that often mimic breast abscess or carcinoma. FNAC is essential to guide the patient to further tests including histochemistry and PCR that can be used as more sensitive and time effective detection modalities.&lt;/p&gt;

Aportaciones de las técnicas moleculares en la fase crónica de la Enfermedad de Chagas en ausencia de tratamiento

IntroductionThe chronic phase of Chagas disease (CD) is characterised by a low and intermittent parasitaemia. The Polymerase Chain Reaction (PCR) presents a variable sensitivity in this stage limiting its use as a diagnostic tool. Despite this, the use of PCR in untreated patients can provide information on the parasite behaviour and its presence in peripheral blood. MethodsA timely real-time PCR determination was performed on a cohort of 495 untreated chronic CD patients. Also, a subcohort of 29 patients was followed-up by serial real-time PCR during a period from 8 to 12 months in which they could not have access to the treatment due to lack of supply. ResultsThe positive percentage of real-time PCR in our series was 42%. Nevertheless, real-time PCR positive results were significantly higher in patients with five years or less of residence in Spain (P=.041). The detection of DNA was not related to the existence of cardiac and/or gastrointestinal abnormalities.In the follow-up subgroup, real-time PCR was consistently positive in 13.8% of patients, consistently negative in 31%, and intermittent in 55.2%. ConclusionsThe different real-time PCR results regarding the time of residence suggests the possible relationship of external factors in the parasite presence in peripheral blood. On the other hand, specific host factors may be involved in the behaviour of parasitaemia over time.