scholarly journals Retrospective diagnosis of lymphatic tuberculosis in frozen samples using two genetic amplification methods, Xpert® MTB/RIF ULTRA and Abbott RealTime MTB Assay

2021 ◽  
Author(s):  
Mariana Fernandez-Pittol ◽  
◽  
Yuliya Zboromyrska ◽  
Angely Román ◽  
Griselda Tudó Vilanova ◽  
...  
Keyword(s):  
Gene Amplification ◽  
Sensitivity And Specificity ◽  
Retrospective Diagnosis ◽  
Mycobacterial Culture ◽  
Initial Culture ◽  
Secondary Objective ◽  
Mycobacterium Avium Intracellulare ◽  
Genetic Amplification ◽  
Culture Positive ◽  
Culture Negative

Objectives. The main objective of the present study is to assess the sensitivity and specificity of a retrospective diagnostic of lymphatic tuberculosis (LTB), testing frozen samples using gene amplification PCR methods. The secondary objective was to compare the results of two different commercial tuberculosis gene amplification methods for this purpose. Material and methods. We retrospectively studied 38 frozen samples, previously processed for mycobacterial culture between January 2014 and August 2019. The results of the previous cultures were: 21 samples positive for Mycobacterium tuberculosis complex (MTB) (5 being smear positive), 7 samples culture positive for Mycobacterium avium-intracellulare complex and 10 samples which were mycobacterial culture negative and discarded for LTB diagnosis, used as controls. The samples were processed using two gene amplification methods: Xpert® MTB/RIF Ultra (Cepheid) and Abbott RealTime MTB Assay (Abbott). Results. Compared to initial culture results the sensitivity and specificity of Xpert® MTB/RIF Ultra were 57.1% and 100% and 52.3 % and 92.5%, respectively for the Abbott RealTime MTB assay. The differences were not statiscally significant. In addition, there were no differences according to the period of freezing. Conclusions. Gene amplification of frozen samples confirmed the diagnosis of lymphatic TB in almost 60% of cases, allowing retrospective diagnosis in initially non suspected cases. Both gene amplification techniques tested were equally useful.

scholarly journals Clinical Evaluation of a Blood Assay to Diagnose Paucibacillary Tuberculosis via Bacterial Antigens

2018 ◽  
Vol 64 (5) ◽  
pp. 791-800 ◽  
Author(s):  
Chang Liu ◽  
Christopher J Lyon ◽  
Yang Bu ◽  
Zaian Deng ◽  
Elisabetta Walters ◽  
...  
Keyword(s):  
Direct Detection ◽  
Clinical Performance ◽  
Chinese Adults ◽  
Mycobacterial Culture ◽  
Clinical Sensitivity ◽  
Disease Site ◽  
Early Secretory Antigenic Target ◽  
Tb Diagnostics ◽  
Culture Positive ◽  
Culture Negative

Abstract BACKGROUND The diagnosis of active tuberculosis (TB) cases primarily relies on methods that detect Mycobacterium tuberculosis (Mtb) bacilli or their DNA in patient samples (e.g., mycobacterial culture and Xpert MTB/RIF assays), but these tests have low clinical sensitivity for patients with paucibacillary TB disease. Our goal was to evaluate the clinical performance of a newly developed assay that can rapidly diagnose active TB cases by direct detection of Mtb-derived antigens in patients' blood samples. METHODS Nanoparticle (NanoDisk)-enriched peptides derived from the Mtb virulence factors CFP-10 (10-kDa culture factor protein) and ESAT-6 (6-kDa early secretory antigenic target) were analyzed by high-throughput mass spectrometry (MS). Serum from 294 prospectively enrolled Chinese adults were analyzed with this NanoDisk-MS method to evaluate the performance of direct serum Mtb antigen measurement as a means for rapid diagnosis of active TB cases. RESULTS NanoDisk-MS diagnosed 174 (88.3%) of the study's TB cases, with 95.8% clinical specificity, and with 91.6% and 85.3% clinical sensitivity for culture-positive and culture-negative TB cases, respectively. NanoDisk-MS also exhibited 88% clinical sensitivity for pulmonary and 90% for extrapulmonary TB, exceeding the diagnostic performance of mycobacterial culture for these cases. CONCLUSIONS Direct detection and quantification of serum Mtb antigens by NanoDisk-MS can rapidly and accurately diagnose active TB in adults, independent of disease site or culture status, and outperform Mycobacterium-based TB diagnostics.

Comparison of real-time PCR with fungal culture for the diagnosis of Microsporum canis dermatophytosis in shelter cats: a field study

2017 ◽  
Vol 20 (2) ◽  
pp. 103-107 ◽  
Author(s):  
Linda S Jacobson ◽  
Lauren McIntyre ◽  
Jenny Mykusz
Keyword(s):  
Real Time ◽  
Sensitivity And Specificity ◽  
False Positive ◽  
False Negative ◽  
Microsporum Canis ◽  
Fungal Culture ◽  
Mycological Cure ◽  
Hair Samples ◽  
Culture Positive ◽  
Culture Negative

Objectives Fungal culture requires at least 14 days for a final result, compared with 1–3 days for PCR. The study compared a commercial real-time dermatophyte PCR panel with fungal culture in cats in a shelter setting for: (1) diagnosis of Microsporum canis infection; and (2) determination of mycological cure. Methods This was a cross-sectional, observational study of cats with suspicious skin lesions or suspected exposure to dermatophytosis. Hair samples were collected for fungal culture and PCR prior to treatment and at weekly intervals until two negative culture results were obtained. Results One hundred and thirty-two cats were included, of which 28 (21.2%) were culture positive and 104 (78.8%) culture-negative for M canis. PCR correctly identified all culture-positive cats and 92/104 culture negative cats; there were 12 false-positive PCR results. The sensitivity and specificity of PCR were 100% (95% confidence interval [CI] 87.7–100) and 88.5% (95% CI 80.7–93.9), respectively. Data from 17 cats were available for assessment of mycological cure. At the time of the first and second negative fungal cultures, 14/17 (82.4%) and 11/17 (64.7%) tested PCR positive, respectively. Conclusions and relevance PCR showed high sensitivity and specificity for diagnosis of M canis dermatophytosis compared with fungal culture, but was unreliable for identifying mycological cure. False-positive results were relatively common. There were no false-negative PCR results and a negative PCR test was a reliable finding in this study. The ability to rapidly diagnose or rule out dermatophytosis could be a valuable tool to increase life-saving capacity in animal shelters.

scholarly journals Bacteremic sepsis leads to higher mortality when adjusting for confounders with propensity score matching

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lisa Mellhammar ◽  
Fredrik Kahn ◽  
Caroline Whitlow ◽  
Thomas Kander ◽  
Bertil Christensson ◽  
...  
Keyword(s):  
Intensive Care ◽  
Clinical Review ◽  
Pathogen Detection ◽  
Mortality Rates ◽  
Blood Cultures ◽  
Population Heterogeneity ◽  
Sepsis Diagnosis ◽  
Culture Positive ◽  
Culture Negative ◽  
Microbial Samples

AbstractOne can falsely assume that it is well known that bacteremia is associated with higher mortality in sepsis. Only a handful of studies specifically focus on the comparison of culture-negative and culture-positive sepsis with different conclusions depending on study design. The aim of this study was to describe outcome for critically ill patients with either culture-positive or -negative sepsis in a clinical review. We also aimed to identify subphenotypes of sepsis with culture status included as candidate clinical variables. Out of 784 patients treated in intensive care with a sepsis diagnosis, blood cultures were missing in 140 excluded patients and 95 excluded patients did not fulfill a sepsis diagnosis. Of 549 included patients, 295 (54%) had bacteremia, 90 (16%) were non-bacteremic but with relevant pathogens detected and in 164 (30%) no relevant pathogen was detected. After adjusting for confounders, 90-day mortality was higher in bacteremic patients, 47%, than in non-bacteremic patients, 36%, p = 0.04. We identified 8 subphenotypes, with different mortality rates, where pathogen detection in microbial samples were important for subphenotype distinction and outcome. In conclusion, bacteremic patients had higher mortality than their non-bacteremic counter-parts and bacteremia is more common in sepsis when studied in a clinical review. For reducing population heterogeneity and improve the outcome of trials and treatment for sepsis, distinction of subphenotypes might be useful and pathogen detection an important factor.

scholarly journals Culture-negative versus culture-positive in pyogenic spondylitis and analysis of risk factors for relapse

2021 ◽  
pp. 1-5
Author(s):  
Guohua Dai ◽  
Shuzhong Li ◽  
Chuqiang Yin ◽  
Yuanliang Sun ◽  
Jianwen Hou ◽  
...  
Keyword(s):  
Risk Factors ◽  
Pyogenic Spondylitis ◽  
Culture Positive ◽  
Culture Negative

scholarly journals Association Between Diabetic Foot Infection Wound Culture Positivity and 1-Year Admission for Invasive Infection: A Multi-Center Cohort Study

2021 ◽  
Author(s):  
Westyn Branch-Elliman ◽  
Daniel Sturgeon ◽  
Adolf W Karchmer ◽  
Hillary J Mull
Keyword(s):  
Diabetic Foot ◽  
Systemic Infection ◽  
Causative Organism ◽  
Invasive Infection ◽  
Diabetic Foot Ulcers ◽  
Diabetic Foot Infections ◽  
Culture Positivity ◽  
Wound Culture ◽  
Culture Positive ◽  
Culture Negative

Abstract Inpatients with culture-positive diabetic foot infections are at elevated risk for subsequent invasive infection with the same causative organism. In outpatients with index diabetic foot ulcers, we found that wound culture positivity was independently associated with increased odds of 1-year admission for systemic infection when compared to culture-negative wounds.

scholarly journals Evaluation of the performance of clinical predictors in estimating the probability of pulmonary tuberculosis among smear-negative cases in Northern Ethiopia: a cross-sectional study

BMJ Open ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. e037913
Author(s):  
Mala George ◽  
Geert-Jan Dinant ◽  
Efrem Kentiba ◽  
Teklu Teshome ◽  
Abinet Teshome ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Cross Sectional Study ◽  
Clinical Suspicion ◽  
Secondary Outcome ◽  
Northern Ethiopia ◽  
Sectional Study ◽  
Cross Sectional ◽  
Smear Negative ◽  
Culture Positive ◽  
Culture Negative

ObjectivesTo evaluate the performance of the predictors in estimating the probability of pulmonary tuberculosis (PTB) when all versus only significant variables are combined into a decision model (1) among all clinical suspects and (2) among smear-negative cases based on the results of culture tests.DesignA cross-sectional study.SettingTwo public referral hospitals in Tigray, Ethiopia.ParticipantsA total of 426 consecutive adult patients admitted to the hospitals with clinical suspicion of PTB were screened by sputum smear microscopy and chest radiograph (chest X-ray (CXR)) in accordance with the Ethiopian guidelines of the National Tuberculosis and Leprosy Program. Discontinuation of antituberculosis therapy in the past 3 months, unproductive cough, HIV positivity and unwillingness to give written informed consent were the basis of exclusion from the study.Primary and secondary outcome measuresA total of 354 patients were included in the final analysis, while 72 patients were excluded because culture tests were not done.ResultsThe strongest predictive variables of culture-positive PTB among patients with clinical suspicion were a positive smear test (OR 172; 95% CI 23.23 to 1273.54) and having CXR lesions compatible with PTB (OR 10.401; 95% CI 5.862 to 18.454). The regression model had a good predictive performance for identifying culture-positive PTB among patients with clinical suspicion (area under the curve (AUC) 0.84), but it was rather poor in patients with a negative smear result (AUC 0.64). Combining all the predictors in the model compared with only the independent significant variables did not really improve its performance to identify culture-positive (AUC 0.84–0.87) and culture-negative (AUC 0.64–0.69) PTB.ConclusionsOur finding suggests that predictive models based on clinical variables will not be useful to discriminate patients with culture-negative PTB from patients with culture-positive PTB among patients with smear-negative cases.

Circulating microbial cell-free DNA is associated with inflammatory host-responses in severe pneumonia

Thorax ◽  
2021 ◽  
pp. thoraxjnl-2020-216013
Author(s):  
Haopu Yang ◽  
Ghady Haidar ◽  
Nameer S Al-Yousif ◽  
Haris Zia ◽  
Daniel Kotok ◽  
...  
Keyword(s):  
Large Scale ◽  
Inflammatory Responses ◽  
Severe Pneumonia ◽  
Systemic Circulation ◽  
Microbial Cell ◽  
Metagenomic Sequencing ◽  
Cell Free Dna ◽  
Free Dna ◽  
Culture Positive ◽  
Culture Negative

Host inflammatory responses predict worse outcome in severe pneumonia, yet little is known about what drives dysregulated inflammation. We performed metagenomic sequencing of microbial cell-free DNA (mcfDNA) in 83 mechanically ventilated patients (26 culture-positive, 41 culture-negative pneumonia, 16 uninfected controls). Culture-positive patients had higher levels of mcfDNA than those with culture-negative pneumonia and uninfected controls (p<0.005). Plasma levels of inflammatory biomarkers (fractalkine, procalcitonin, pentraxin-3 and suppression of tumorigenicity-2) were independently associated with mcfDNA levels (adjusted p<0.05) among all patients with pneumonia. Such host–microbe interactions in the systemic circulation of patients with severe pneumonia warrant further large-scale clinical and mechanistic investigations.

scholarly journals Procalcitonin and Interleukin-6 for predicting culturenegative and culture positive bacterial sepsis in critically ill patients with systemic inflammatory response syndrome

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Mohd Basri Mat Nor ◽  
Azrina Md Ralib
Keyword(s):  
Systemic Inflammatory Response Syndrome ◽  
Inflammatory Response ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Interleukin 6 ◽  
Systemic Inflammatory Response ◽  
Bacterial Sepsis ◽  
Saps Ii Score ◽  
Culture Positive ◽  
Culture Negative

Introduction: Differentiation between culture-negative bacterial sepsis (BS), culturepositive BS and non-infectious systemic inflammatory response syndrome (SIRS) among critically ill patients remains a diagnostic challenge to the intensive care unit (ICU) physicians. This study aimed to evaluate the role of procalcitonin (PCT) and interleukin-6 (IL-6) in predicting non-infectious SIRS, culture-negative BS and culture-positive BS in the ICU. Methods: This prospective observational study was conducted in a tertiary ICU in Pahang. The patients were divided into sepsis and non-infectious SIRS based on clinical assessment with or without positive cultures. Patients with positive cultures were further divided into bacteraemia and positive other culture. The PCT and IL-6 were measured daily over the first 3 days. Results: Two hundred and thirty nine consecutive patients diagnosed with SIRS were recruited, of whom 164 (69%) had sepsis. Among sepsis patients, there were 62 (37.8%) culture positive and 102 (62.2%) culture negative. Of these, 27 (16.5%) develop bacteraemia. The most common site of infection was respiratory (34.4%). Post-LSD analyses showed significant difference in the PCT between culture negative sepsis and SIRS (p=0.01); and positive other culture and SIRS (p=0.04).  On the other hand IL-6 cannot differentiate between SIRS and negative culture sepsis (p=0.06). Both PCT and IL-6 predicted bacteraemia with an AUC of 0.70 (0.57 to 0.82) and 0.68 (0.53 to 0.70). IL-6 is independently associated with bacteraemia and other culture after adjusting for age, sex, hypertension, SAPS II score and day 1 PCT. Conclusions: Procalcitonin but not Interleukin-6 is able to differentiate SIRS from culture-negative BS. However, IL-6 is independently associated with bacteraemia and other culture.

#54: Sensitivity and Specificity of Procalcitonin vs C Reactive Protein in Identifying Pediatric Bacterial infections

2021 ◽  
Vol 10 (Supplement_2) ◽  
pp. S16-S16
Author(s):  
Sara Kim ◽  
Avni Bhatt ◽  
Silvana Carr ◽  
Frances Saccoccio ◽  
Judy Lew
Keyword(s):  
Urinary Tract ◽  
Sensitivity And Specificity ◽  
Urinary Tract Infections ◽  
Bacterial Infections ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Culture Positivity ◽  
Serious Bacterial Infections ◽  
Tract Infections ◽  
Culture Positive

Abstract Background Procalcitonin (PCT) and c-reactive protein (CRP) have been utilized in children to assess risk for serious bacterial infections. However, there have been different cut-offs reported for PCT and CRP, which yield different sensitivity and specificity. This study aims to compare the sensitivity and specificity of PCT and CRP in detecting serious bacterial infections (SBIs), specifically urinary tract infections, bacteremia and meningitis. Methods In this retrospective, single center cohort study from January 2018 to June 2019, we analyzed children with a fever greater than 38C with both PCT and CRP value within 24 hours of admission. Each patient had a blood, urine and/or cerebrospinal fluid culture collected within 48 hours of admission. No antibiotics were administered from the admitting hospital prior to collection of the PCT or CRP. Our gold standard was a positive culture obtained from blood, cerebrospinal fluid, or urine. The statistical analysis included categorical variables as percentages and compared them using the Fisher exact test. The optimal cutoff values for PCT or CRP were based on ROC curve analysis and Youden Index. Sensitivity and specificity analysis were based on literature review cut offs and ROC curves cut offs. Results Among 202 children, we had 45 culture positive patients (11 urinary tract infections, 4 meningitis, and 32 bacteremia). The patients with culture positivity had higher PCT levels (7.9 ng/mL vs 2.5 ng/mL, P=0.0111), CRP levels (110.9 mg/L vs 49.6 mg/L, P&lt;0.0001) and temperature (39.2C vs 39C, P&lt;0.0052). The area under the curve (AUC) comparing culture positivity vs negativity for all culture types was 0.72 (p&lt;0.0001) for PCT and 0.66 (p=0.001) for CRP. In Figure 1, the AUC for culture positive bacteremia was 0.68 (p=0.0011) for PCT and 0.70 (p=0.0003). The AUC for culture positive urinary tract infections (UTI) only was 0.86 (p=0.0001) for PCT and 0.70 (p=0.3607). For the cut-off value for PCT at 0.5 ng/mL, the sensitivity and specificity was 64% (95% confidence interval [CI] 0.5–0.77) and 70% (95% CI 0.62–0.77) respectively in identifying children with bacterial infection. For the cut-off value for CRP at 20 mg/L, the sensitivity and specificity was 67% (95% CI 0.52–0.79) and 52% (95% CI 0.44–0.59) respectively in identifying children with bacterial infection. Conclusion In this study, PCT and CRP are nearly equivalent classifiers for detecting SBIs as a group and bacteremia, but PCT is statistically better for urinary tract infections; however, the clinical utility is unknown.

Multicentre registry data analysis comparing outcomes of culture-negative peritonitis and different subtypes of culture-positive peritonitis in peritoneal dialysis patients

2020 ◽  
Vol 40 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Htay Htay ◽  
Yeoungjee Cho ◽  
Elaine M Pascoe ◽  
Carmel Hawley ◽  
Philip A Clayton ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Primary Outcome ◽  
Catheter Removal ◽  
Dialysis Patients ◽  
Gram Positive ◽  
Pseudomonas Species ◽  
Gram Negative Organisms ◽  
Culture Positive ◽  
Culture Negative ◽  
Related Mortality

Background: The outcomes of culture-negative peritonitis in peritoneal dialysis (PD) patients have been reported to be superior to those of culture-positive peritonitis. The current study aimed to examine whether this observation also applied to different subtypes of culture-positive peritonitis. Methods: This multicentre registry study included all episodes of peritonitis in adult PD patients in Australia between 2004 and 2014. The primary outcome was medical cure. Secondary outcomes were catheter removal, hemodialysis transfer, relapsing/recurrent peritonitis and peritonitis-related death. These outcomes were analyzed using mixed effects logistic regression. Results: Overall, 11,122 episodes of peritonitis occurring in 5367 patients were included. A total of 1760 (16%) episodes were culture-negative, of which 77% were medically cured. Compared with culture-negative peritonitis, the odds of medical cure were lower in peritonitis caused by Staphylococcus aureus (adjusted odds ratio (OR) 0.62, 95% confidence interval (CI) 0.52–0.73), Pseudomonas species (OR 0.20, 95% CI 0.16–0.26), other gram-negative organisms (OR 0.48, 95% CI 0.41–0.56), polymicrobial organisms (OR 0.30, 95% CI 0.25–0.35), fungi (OR 0.02, 95% CI 0.01–0.03), and other organisms (OR 0.61, 95% CI 0.49–0.76), while the odds were similar in other (non-staphylococcal) gram-positive organisms (OR 1.11, 95% CI 0.97–1.28). Similar results were observed for catheter removal and hemodialysis transfer. Compared with culture-negative peritonitis, peritonitis-related mortality was significantly higher in culture-positive peritonitis except that due to other gram-positive organisms. There was no difference in the odds of relapsing/recurrent peritonitis between culture-negative and culture-positive peritonitis. Conclusion: Culture-negative peritonitis had superior outcomes compared to culture-positive peritonitis except for non-staphylococcal gram-positive peritonitis.

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