scholarly journals Comparison of results obtained by widal agglutination test & polymerase chain reaction among clinically suspected typhoid fever cases

2015 ◽  
Vol 30 (2) ◽  
pp. 46-50
Author(s):  
Shafinaz Khan ◽  
Md Ruhul Amin Miah ◽  
Shammin Haque ◽  
Chowdhury Rafia Naheen
Keyword(s):  
Polymerase Chain Reaction ◽  
Blood Culture ◽  
Typhoid Fever ◽  
False Negative ◽  
Salmonella Typhi ◽  
Widal Test ◽  
Chain Reaction ◽  
Polymerase Chain ◽  
Positive Results ◽  
Prior Antibiotic Treatment

The diagnosis of typhoid fever currently depends on isolation of Salmonella Typhi from blood. The sensitivity of blood culture is very low due to prior antibiotic treatment which is a common practice in Bangladesh. The sensitivity of blood culture also decreases at later stage of the disease. Widal test is the most utilized test in Bangladesh next to blood culture because it is inexpensive, less invasive. But the result of the test is controversial due to false negative & false positive results in some cases.  In this study, a recently introduced polymerase chain reaction-based technique (which has 100% specificity for S. Typhi) was compared with widal test among 80 clinically suspected typhoid fever cases.  Among 80 cases, the respective figures of positivity for PCR & widal test were 70% & 43.75% respectively.  It can be concluded that PCR based technique is more sensitive & much superior to widal for diagnosis of typhoid fever. DOI: http://dx.doi.org/10.3329/bjpp.v30i2.22683 Bangladesh J Physiol Pharmacol 2014; 30(2): 46-50

scholarly journals Enhanced detection rate of typhoid fever among clinically suspected patients in a tertiary referral hospital in Dhaka, Bangladesh using nested polymerase chain reaction technology

2016 ◽  
Vol 41 (3) ◽  
pp. 138-143
Author(s):  
Shafinaz Khan ◽  
Ruhul Amin Mia ◽  
Sumaiya Khatun
Keyword(s):  
Polymerase Chain Reaction ◽  
Blood Culture ◽  
Typhoid Fever ◽  
Nested Pcr ◽  
Salmonella Typhi ◽  
Chain Reaction ◽  
Tertiary Referral Hospital ◽  
Nested Polymerase Chain Reaction ◽  
Polymerase Chain ◽  
Pcr Targeting

A nested polymerase chain reaction (PCR) specific for Salmonella enterica subspecies enteric serovar Typhi was used for the detection of the pathogen in blood. This study was done during the period of March 2013 to February 2014. A total of 80 clinically suspected cases of typhoid fever were included in the study. Blood was collected from all participating individuals. Nested PCR targeting the flagellin gene (fliC) of Salmonella Typhi & blood culture were done for each of the cases. The positivity rate of PCR & blood culture was 70%& 20% respectively. The positivity rate of PCR was significantly higher than blood culture (P< 0.05). With the nested PCR, S. Typhi DNAs were detected from blood specimens of 67.2% (43/64) patients among the suspected typhoid fever cases on the basis of clinical features but with negative cultures. We conclude that the PCR technique could be used as a novel diagnostic method of typhoid fever, particularly in culture-negative cases in an endemic country like Bangladesh.

Detection of Salmonella Cells within 24 to 26 Hours in Poultry Samples with the Polymerase Chain Reaction BAX System

1998 ◽  
Vol 61 (7) ◽  
pp. 792-795 ◽  
Author(s):  
J. S. BAILEY
Keyword(s):  
Polymerase Chain Reaction ◽  
Polymerase Chain Reaction Product ◽  
False Negative ◽  
Chain Reaction ◽  
Cultural Methods ◽  
Polymerase Chain ◽  
Conventional Methods ◽  
High Degree ◽  
Positive Results ◽  
Method Agreement

BAX, a commercial polymerase chain reaction-based system, was evaluated to determine the efficacy of the system with different concentrations of Salmonella cells in mixed cultures and compared to conventional methods for detection of inoculated Salmonella cells from poultry samples. When present in enrichment broths at levels of 105, 104, and 103 CFU/ml, Salmonella cells were detected in 100, 93, and 41% of samples, respectively. Salmonella cells were detected in 23 of 150 (15%) processed chicken rinse samples with the BAX system compared to 18 of 150 (12%) samples with conventional methods. Salmonella cells were detected in 28 of 50 (56%) ground turkey samples with the BAX system compared to 25 of 50 (50%) samples with conventional methods. Overall there was a 97% method agreement. One false-negative and two false-positive results were obtained with the BAX. Band sizes and intensity of the polymerase chain reaction product were shown to be correlated with estimated numbers of Salmonella CFU present in the enriched and inoculated samples. The assay was able to detect 104 Salmonella CFU/ml of enrichment medium, which allows consistent detection of Salmonella cells within 24 to 26 h. The high degree of sensitivity and specificity of the BAX system make it a reliable alternative to conventional bacterial cultural methods.

scholarly journals Detection of Salmonella typhi in the blood of patients with typhoid fever by polymerase chain reaction.

1993 ◽  
Vol 31 (6) ◽  
pp. 1439-1443 ◽  
Author(s):  
J H Song ◽  
H Cho ◽  
M Y Park ◽  
D S Na ◽  
H B Moon ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Typhoid Fever ◽  
Salmonella Typhi ◽  
Chain Reaction ◽  
Polymerase Chain

scholarly journals Digital Droplet PCR for SARS-CoV-2 Resolves Borderline Cases

2021 ◽  
Author(s):  
Jing Xu ◽  
Timothy Kirtek ◽  
Yan Xu ◽  
Hui Zheng ◽  
Huiyu Yao ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Limit Of Detection ◽  
False Negative ◽  
Accurate Method ◽  
Viral Envelope ◽  
Chain Reaction ◽  
Borderline Cases ◽  
Droplet Pcr ◽  
Polymerase Chain ◽  
Digital Polymerase Chain Reaction

Abstract Objectives The Bio-Rad SARS-CoV-2 ddPCR Kit (Bio-Rad Laboratories) was the first droplet digital polymerase chain reaction (ddPCR) assay to receive Food and Drug Administration (FDA) Emergency Use Authorization approval, but it has not been evaluated clinically. We describe the performance of ddPCR—in particular, its ability to confirm weak-positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) results. Methods We clinically validated the Bio-Rad Triplex Probe ddPCR Assay. The limit of detection was determined by using serial dilutions of SARS-CoV-2 RNA in an artificial viral envelope. The ddPCR assay was performed according to the manufacturer’s specifications on specimens confirmed to be positive (n = 48) or negative (n = 30) by an FDA-validated reverse transcription–polymerase chain reaction assay on the m2000 RealTime system (Abbott). Ten borderline positive cases were also evaluated. Results The limit of detection was 50 copies/mL (19 of 20 positive). Forty-seven specimens spanning a range of quantification cycles (2.9-25.9 cycle numbers) were positive by this assay (47 of 48; 97.9% positive precent agreement), and 30 negative samples were confirmed as negative (30 of 30; 100% negative percent agreement). Nine of 10 borderline cases were positive when tested in triplicate. Conclusions The ddPCR of SARS-CoV-2 is an accurate method, with superior sensitivity for viral RNA detection. It could provide definitive evaluation of borderline positive cases or suspected false-negative cases.

scholarly journals Validation of polymerase chain reaction in experimental sepsis diagnosis beyond blood culture

Critical Care ◽  
2008 ◽  
Vol 12 (Suppl 5) ◽  
pp. P47
Author(s):  
Marcello Ruiz-Silva ◽  
Derci Sa-Filho ◽  
Marcos Caseiro ◽  
Ivan Koh
Keyword(s):  
Polymerase Chain Reaction ◽  
Blood Culture ◽  
Experimental Sepsis ◽  
Chain Reaction ◽  
Sepsis Diagnosis ◽  
Polymerase Chain

scholarly journals UTILITY OF ANTIGEN DETECTION TEST AND POLYMERASE CHAIN REACTION IN THE DIFFERENTIATION OF TUBERCULOUS AND NON-TUBERCULOUS MYCOBACTERIA

2017 ◽  
Vol 10 (6) ◽  
pp. 289
Author(s):  
Yogita Singh ◽  
Raji Vasanth ◽  
Shrikala Baliga ◽  
Dhanashree B
Keyword(s):  
Polymerase Chain Reaction ◽  
False Negative ◽  
Diagnostic Methods ◽  
Clinical Samples ◽  
Chain Reaction ◽  
College Hospital ◽  
Medical College ◽  
Negative Results ◽  
Polymerase Chain ◽  
Mycobacterium Spp

Objectives: Cultivation and identification of mycobacteria to species level remains difficult and time-consuming. Hence, easy and rapid diagnostic methods are necessary for the differentiation of Mycobacterium tuberculosis (MTB) from non-tuberculous mycobacteria (NTM). The present study aims to detect and differentiate MTB from NTM isolated from clinical samples by immunochromatographic test (ICT) and polymerase chain reaction (PCR). Methods: Over a period of 1 year, clinical samples (n=496) received from suspected cases of TB, at the Department of Microbiology, Kasturba Medical College Hospital, Mangalore were cultured to isolate Mycobacterium spp. Identification of all the isolates was done by conventional biochemical technique, ICT, and PCR. Results: Among the 496 samples processed, 49 (9.87%) were acid-fast bacilli smear positive and 59 (11.89%) samples showed the growth of Mycobacterium spp. Among these, 10 were rapid growers, 49 were slow-growing mycobacteria, out of which 30 were MTB as identified by conventional biochemical reaction. Out of 59 Mycobacterial isolates subjected to ICT for the detection of MPT 64 antigen, only 28 were identified as MTB. However, all the 30 isolates were correctly identified as MTB by PCR. Conclusion: Hence, PCR is essential for rapid differentiation of non-tuberculous Mycobacterium from MTB. False negative results seen with immunochromatographic MPT 64 antigen assay could be due to mutations within the mpt64 gene. Further studies are necessary to characterize these PCR-positive and immunochromatographic assay negative MTB isolates.

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