Studies on Diagnosis of Bovine Brucellosis by Immunocyto-chemistry and Immunohistochemistry

Author(s):  
K.S. Lakshmikanth ◽  
N.S. Sharma ◽  
D. Pathak ◽  
Paviter Kaur

Background: Brucellosis is a major threat to livestock economy and an important zoonotic disease. A rapid and accurate diagnosis is a necessity to curb the spread and progress of the disease. The current study aimed to evaluate sensitivity of Immunocytochemistry and Immunohistochemistry methods for detection of Brucella spp.Methods: A total of 50 samples comprising of fetal stomach content, vaginal discharges and placenta were collected from cattle and buffaloes suffering from abortions and other reproductive disorders in and around Ludhiana, Punjab during the period 2017-2018. All the samples were processed for isolation and confirmed with biochemical analysis and Polymerase chain reaction (PCR). The isolates obtained and 43 clinical samples excluding placental samples were subjected to Immunocytochemistry (ICC). Immunohistochemistry (ICH) was performed on placental samples.Result: A total of four isolates were recovered from the screened samples. The four isolates also yielded positive results in Immunocytochemistry. Among the 43 clinical samples screened by Immunocytochemistry, five were positive, however only 3 isolates were recovered on isolation. A total of seven placental tissue samples were processed and subjected to immunohistochemistry. Of the three placental samples positive by immunohistochemistry, only one sample was isolated on culture. The results suggest that both immunocytochemistry and immunohistochemistry are sensitive diagnostic techniques in comparison to isolation.

2013 ◽  
Vol 33 (12) ◽  
pp. 1448-1452 ◽  
Author(s):  
Marcelo M. Silveira ◽  
Daphine A.J. Paula ◽  
Maria C. Silva ◽  
Leticia C. Pitchenin ◽  
Raquel A.S. Cruz ◽  
...  

Conidiobolomycosis is a granulomatous disease caused by the fungus Conidiobolus spp. in humans and animals. Traditional technique for diagnosis of the disease is isolation of the agent associated with the presence of typical clinical signs and pathological conditions. The aim of this study was to describe the development of a specific polymerase chain reaction (PCR) test for Conidiobolus lamprauges to detect the fungus in clinical samples. Samples from suspected animals were collected and submitted to isolation, histopathological analysis and amplification by PCR. DNA from tissues was subjected to PCR with fungi universal primers 18S rDNA gene, and specific primers were designed based on the same gene in C. lamprauges that generated products of about 540 bp and 222 bp respectively. The culture was positive in 26.6% of clinical samples. The PCR technique for C. lamprauges showed amplification of DNA from fresh tissues (80%) and paraffin sections (44.4%). In conclusion, the PCR technique described here demonstrated a high sensitivity and specificity for detection of fungal DNA in tissue samples, providing a tool for the rapid diagnosis of C. lamprauges.


Author(s):  
Shahrzad Azizi ◽  
Reza Kheirandish ◽  
Elham Rahimi

Leptospirosis is a worldwide zoonotic disease that is caused by Gram-negative spirochaetes, Leptospira species. Affected animals excrete the organism in the urine into the environment and act as a source of infection. Cattle are maintenance hosts for some serovars of leptospirosis and are important in the transmission of the infection to humans. At post mortem examination, affected cattle show white spots in their kidneys but these are not specific for leptospirosis. Sometimes it is necessary that leptospirosis be diagnosed in the carcass. Different direct methods, including polymerase chain reaction (PCR), Warthin-Starry silver stain (WS), immunofluorescence (IF) and immunohistochemistry (IHC) can be used in order to diagnose leptospirosis in the affected tissues, such as kidney. The main advantage of the WS technique is direct visualisation of the bacteria in the tissue samples. Silver staining is useful for retrospective studies on formalin-fixed and paraffin-embedded samples but little information is available on the sensitivity and specificity of the technique. The present study aimed to find a simple and inexpensive method that can be used in any laboratory and that also, if clinical samples are not available, can detect Leptospira in tissue samples post mortem. This study was performed on 19 paraffin-embedded kidneys of slaughtered cows that grossly had focal to multifocal white spots. Leptospirosis was confirmed in these samples with PCR based on the LipL32 gene. Out of 19 PCR positive kidneys, Leptospira was identified in 13 stained samples by WS. The kidneys revealed different grades of interstitial nephritis. No relationship was found between severity of lesions and presence of leptospires in the kidneys. The PCR results on the urine and blood were consistent with matching WS stained kidneys. Out of 13 kidneys that were positive with silver staining, 7 matching blood and 10 matching urine samples were confirmed positive for leptospirosis with PCR. In this study, the WS technique provided fewer positive results than PCR. This may be as a result of a low burden of Leptospira in the kidney, but the sensitivity of WS staining needs more investigation.


2011 ◽  
Vol 32 (5) ◽  
pp. 510-512 ◽  
Author(s):  
Maria Scaturro ◽  
Stefano Fontana ◽  
Maria Luisa Ricci

The source of infection of a hospital-acquired Legionnaires' disease case was determined for the first time by nested polymerase chain reaction based on sequence-based typing. The typing was performed directly on DNA extracted from tissue samples, allowing a rapid epidemiological correlation with environmental isolates.


2014 ◽  
Vol 104 (3) ◽  
pp. 233-237 ◽  
Author(s):  
María José Iglesias Sánchez ◽  
Ana María Pérez Pico ◽  
Félix Marcos Tejedor ◽  
María Jesús Iglesias Sánchez ◽  
Raquel Mayordomo Acevedo

Background Dermatomycoses are a group of pathologic abnormalities frequently seen in clinical practice, and their prevalence has increased in recent decades. Diagnostic confirmation of mycotic infection in nails is essential because there are several pathologic conditions with similar clinical manifestations. The classical method for confirming the presence of fungus in nail is microbiological culture and the identification of morphological structures by microscopy. Methods We devised a nested polymerase chain reaction (PCR) that amplifies specific DNA sequences of dermatophyte fungus that is notably faster than the 3 to 4 weeks that the traditional procedure takes. We compared this new technique and the conventional plate culture method in 225 nail samples. The results were subjected to statistical analysis. Results We found concordance in 78.2% of the samples analyzed by the two methods and increased sensitivity when simultaneously using the two methods to analyze clinical samples. Now we can confirm the presence of dermatophyte fungus in most of the positive samples in just 24 hours, and we have to wait for the result of culture only in negative PCR cases. Conclusions Although this PCR cannot, at present, substitute for the traditional culture method in the detection of dermatophyte infection of the nails, it can be used as a complementary technique because its main advantage lies in the significant reduction of time used for diagnosis, in addition to higher sensitivity.


2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Yang Zhang ◽  
Chunyang Dai ◽  
Huiyan Wang ◽  
Yong Gao ◽  
Tuantuan Li ◽  
...  

Abstract Background Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is posing a serious threat to global public health. Reverse transcriptase real-time quantitative polymerase chain reaction (qRT-PCR) is widely used as the gold standard for clinical detection of SARS-CoV-2. Due to technical limitations, the reported positive rates of qRT-PCR assay of throat swab samples vary from 30 to 60%. Therefore, the evaluation of alternative strategies to overcome the limitations of qRT-PCR is required. A previous study reported that one-step nested (OSN)-qRT-PCR revealed better suitability for detecting SARS-CoV-2. However, information on the analytical performance of OSN-qRT-PCR is insufficient. Method In this study, we aimed to analyze OSN-qRT-PCR by comparing it with droplet digital PCR (ddPCR) and qRT-PCR by using a dilution series of SARS-CoV-2 pseudoviral RNA and a quality assessment panel. The clinical performance of OSN-qRT-PCR was also validated and compared with ddPCR and qRT-PCR using specimens from COVID-19 patients. Result The limit of detection (copies/ml) of qRT-PCR, ddPCR, and OSN-qRT-PCR were 520.1 (95% CI: 363.23–1145.69) for ORF1ab and 528.1 (95% CI: 347.7–1248.7) for N, 401.8 (95% CI: 284.8–938.3) for ORF1ab and 336.8 (95% CI: 244.6–792.5) for N, and 194.74 (95% CI: 139.7–430.9) for ORF1ab and 189.1 (95% CI: 130.9–433.9) for N, respectively. Of the 34 clinical samples from COVID-19 patients, the positive rates of OSN-qRT-PCR, ddPCR, and qRT-PCR were 82.35% (28/34), 67.65% (23/34), and 58.82% (20/34), respectively. Conclusion In conclusion, the highly sensitive and specific OSN-qRT-PCR assay is superior to ddPCR and qRT-PCR assays, showing great potential as a technique for detection of SARS-CoV-2 in patients with low viral loads.


2017 ◽  
Vol 26 (3) ◽  
pp. 292-298 ◽  
Author(s):  
Cesar Augusto Barbosa de Macedo ◽  
Madlaine Frigo Silveira Barbosa de Macedo ◽  
Ana Carolina Miura ◽  
Alessandra Taroda ◽  
Sergio Tosi Cardim ◽  
...  

Abstract The aim of the present study was to investigate the occurrence of N. caninum associated with abortions of dairy cattle from Santa Catarina state, southern Brazil by using enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC), and polymerase chain reaction (PCR). Blood from dairy cows that aborted along with intrathoracic fluid and tissue samples (brain, heart, liver, and lung) from their fetuses were collected and used for serology; PCR, histopathological, and immunohistochemistry (IHC) evaluations were also conducted. Twenty-one cows (51.2%) out of 41, and eight fetuses (26.7%) out of 30 were ELISA (HerdCheck, IDEXX) positive for N. caninum. Dams > 36 months of age had a higher risk of being serum positive than younger animals. PCR and IHC revealed that 38.8% (14/36) and 25.0% (9/36) of the fetuses were positive for N. caninum, respectively for each of the tests. Seropositive cows had a higher frequency of fetuses that were also positive by either intrathoracic fluid, PCR, or IHC. In summary, the present study observed a high frequency of N. caninum in abortions from dairy cows from southern Brazil, with a higher N. caninum prevalence found in cows that were older than 36 months. In addition, serology, PCR, and IHC should be used all together for better diagnosis of neosporosis in cattle.


2009 ◽  
Vol 21 (5) ◽  
pp. 701-706 ◽  
Author(s):  
Ho To ◽  
Tomohiro Koyama ◽  
Shinya Nagai ◽  
Kotaro Tuchiya ◽  
Tetsuo Nunoya

Quantitative real-time polymerase chain reaction (qPCR) assays were developed and validated in combination with enrichment culture for the detection and discrimination of Erysipelothrix rhusiopathiae and other Erysipelothrix species from tissue samples. The targets for SYBR green qPCR assays were the 16S ribosomal RNA gene for Erysipelothrix species and a gene involved in capsular formation for E. rhusiopathiae. The specificity of the assays was assessed with Erysipelothrix species and other related bacterial species. The limit of detection was found to be 5 colony-forming units per reaction. Amplification of DNA extracted from spleen and joint samples spiked with increasing quantities of Erysipelothrix cells was shown to be equally sensitive to DNA extracted from a pure bacterial culture. The assays were evaluated with 88 tissue samples from 3 experimentally infected pigs and 50 mice and with 36 tissue samples from 3 naturally infected pigs and 11 noninfected pigs. Results were compared with those of direct qPCR and conventional culture. The qPCR after enrichment increased the diagnostic sensitivity over that of culture and qPCR, thereby significantly reducing the total time taken for the detection of E. rhusiopathiae and other Erysipelothrix species. Therefore, this technique could be used for practical applications.


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