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

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.

2015 ◽  
Vol 30 (2) ◽  
pp. 46-50
Author(s):  
Shafinaz Khan ◽  
Md Ruhul Amin Miah ◽  
Shammin Haque ◽  
Chowdhury Rafia Naheen

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


Author(s):  
Jing Xu ◽  
Timothy Kirtek ◽  
Yan Xu ◽  
Hui Zheng ◽  
Huiyu Yao ◽  
...  

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.


Author(s):  
Yogita Singh ◽  
Raji Vasanth ◽  
Shrikala Baliga ◽  
Dhanashree B

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.


2004 ◽  
Vol 46 (4) ◽  
pp. 183-187 ◽  
Author(s):  
Silvia Maria Di Santi ◽  
Karin Kirchgatter ◽  
Karen Cristina Sant'Anna Brunialti ◽  
Alessandra Mota Oliveira ◽  
Sergio Roberto Santos Ferreira ◽  
...  

Although the Giemsa-stained thick blood smear (GTS) remains the gold standard for the diagnosis of malaria, molecular methods are more sensitive and specific to detect parasites and can be used at reference centers to evaluate the performance of microscopy. The description of the Plasmodium falciparum, P. vivax, P. malariae and P. ovale ssrRNA gene sequences allowed the development of a polymerase chain reaction (PCR) that had been used to differentiate the four species. The objective of this study was to determine Plasmodium species through PCR in 190 positive smears from patients in order to verify the quality of diagnosis at SUCEN's Malaria Laboratory. Considering only the 131 positive results in both techniques, GTS detected 4.6% of mixed and 3.1% of P. malariae infections whereas PCR identified 19.1% and 13.8%, respectively.


2021 ◽  
pp. 2878-2882
Author(s):  
Sirikanda Thanasuwan ◽  
Anupong Tankrathok

Background and Aim: Fasciola spp. are important foodborne trematodes and waterborne zoonotic parasites that cause health problems and economic losses worldwide, including in Thailand. Fasciola spp. are usually detected by sedimentation or the formalin-ethyl acetate concentration technique (FECT) under microscopy, which is less specific and sensitive. Accurate detection is important to detect real incidence for protection against and elimination of fasciolosis in the area. This study aimed to determine the distribution of Fasciola spp. and compare the specificity and sensitivity of FECT under microscopy to that of polymerase chain reaction (PCR) in cattle feces. Materials and Methods: The study was conducted in Kalasin Province, Thailand. Feces of 46 cattle were investigated for infection with Fasciola spp. To detect infection, FECT under microscopy and PCR amplification of the 28S rRNA gene of Fasciola spp. were used to identify egg parasites. Results: Feces of 16 of 46 (34.78%) cattle were positive for Fasciola spp. using FECT under microscopy, whereas PCR showed that 67.39% (31 of 46) were positive for Fasciola spp. False-negative results were as high as 32.61% when diagnosed under microscopy. Conclusion: This study confirmed the infection of cattle with Fasciola spp. in Kalasin Province, indicating that PCR demonstrated higher sensitivity and specificity when diagnosing infection. FECT under microscopy can still be used as a primary and traditional method for diagnosis. However, relapse cases of Fasciola spp. and Paramphistomum spp. should be diagnosed by microscopy combined with PCR. This is the first report on the molecular distribution of fecal samples in cattle in Kalasin Province.


1998 ◽  
Vol 112 (5) ◽  
pp. 494-496 ◽  
Author(s):  
Enis Alpin Güneri ◽  
Ahmet Ömer İkiz ◽  
Nese Atabey ◽  
Özlem İzci ◽  
Semih Sütay

AbstractA parotid gland mass with presenting features of malignancy is a diagnostic and therapeutic challenge. The histological nature of the lesion must be clearly determined before proceeding with facial nerve sacrificing surgery. Although rare, tuberculosis of the parotid gland must be included in the differential diagnosis of a parotid gland mass especially when the social characteristics of the patient suggests a mycobacterial infection. Primary tuberculosis of the parotid gland is generally encountered among populations with a high incidence of pulmonary disease. The difficulty in the differential diagnosis of a parotid gland malignancy may be helped by a high degree of clinical suspicion, since laboratory tests generally do not identify the specific causative organism. This article reports the first case of parotid gland tuberculosis with clinical and radiodiagnostical features simulating malignancy in which the diagnosis was confirmed by the polymerase chain reaction (PCR).


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