• Journal of Microbiology and Biotechnology
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• 제26권11호
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• pp.1855-1862
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• 2016

Cronobacter sakazakii (C. sakazakii) is a foodborne pathogen, posing a high risk of disease to infants and immunocompromised individuals. In order to develop a quick, easy, and sensitive assay for detecting C. sakazakii, a rabbit anti-C. sakazakii immunoglobulin G (IgG) was developed using sonicated cell protein from C. sakazakii. The developed anti-C. sakazakii (IgG) was of good quality and purity, as well as species-specific. The developed rabbit anti-C. sakazakii IgG was attached to the surface of a sulforhodamine B-encapsulated liposome to form an immunoliposome. A test strip was then prepared by coating goat anti-rabbit IgG onto the control line and rabbit anti-C. sakazakii IgG onto the test line, respectively, of a plastic-backed nitrocellulose membrane. A purple color signal both on the test line and the control line indicated the presence of C. sakazakii in the sample, whereas purple color only on the control line indicated the absence of C. sakazakii in the sample. This immunochromatographic strip assay could produce results in 15 min with a limit of detection of $10^7CFU/ml$ in C. sakazakii culture. The immunochromatographic strip assay also showed very good specificity without cross-reactivity with other tested Cronobacter species. Based on these results, the developed immunochromatographic strip assay is efficient for the detection of C. sakazakii and has high potential for on-site detection.

• 대한임상검사과학회지
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• 제42권2호
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• pp.86-91
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• 2010

We evaluated the performance of a novel screening test, PBP2a MRSA rapid kit (Dinona Inc., Iksan, Korea), for methicillin-resistant Staphylococcus aureus (MRSA) based on a immunochromatographic assay. The test is able to detect penicillin-binding protein 2a (PBP2a) using the nasal specimens from health care workers. The nasal specimens were obtained from 69 healthcare workers and were incubated in enrichment broth followed eight hours incubatin in BHI with cefoxitin $4{\mu}g/mL$. These broth were tested by PBP2a Rapid Kit. The enrichment broths were also directly tested for tube coagulase using the conventional identification method. 19 of 22 MRSA showed positive results by PBP2a rapid test and direct coagulase test (the sensitivity for detection of MRSA, 86.36%). While, 8 of 47 non-MRSA showed false positive results for the two tests. All of the 8 non-MRSA which showed false positive were co-colonizing isolates with MRCNS and MSSA. In addition, 46 of 49 methicillin-resistant staphylococci (MRS) showed positive results for PBP2a MRSA rapid kit (the sensitivity for detection of MRS, 93.8%), and all of 20 non-MRS showed negative results (specificity, 100%). The combination of PBP2a MRSA rapid kit and direct coagulase test showed the good sensitivity for detection of MRSA from anterior nares but frequently showed false positive results from the co-colonizing carrier with MRCNS and MSSA.

• Tuberculosis and Respiratory Diseases
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• 제47권5호
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• pp.586-597
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• 1999

연구배경: 객담 도말 및 배양 검사나 방사선학적 검사 등의 기존의 결핵 진단 방법은 낮은 민감도와 진단까지 소요되는 기간이 길다는 단점이 있어서 결핵의 조기 진단 및 치료에 제한점이 있었다. 최근에 혈청학적 진단 방법의 하나로 개발된 immunochromatographic assay 기구들이 소개되고, 외국에서 비교적 높은 진단율를 보여, 결핵 유병율이 높은 국내에서 그 유용성을 평가하고, 질병 양상에 따른 차이점을 조사하여, 기존의 결핵 진단 방법들의 문제점을 해결할 수 있는지 알아보고자하였다. 연구방법: 환자군을 폐결핵 환자군(36명), 폐외결핵 환자군(3명) 및 두 가지 모두 이환된 군(22명)으로 나누었으며, 대조군은 과거 결핵 병력이 있는 비활동성 결핵환자(17명), 결핵이외의 폐질환자(16명) 및 폐질환이 없는 심장 환자(14명)를 대상으로 38kDa 항체를 포함한 ICT tuberculosis 또는 BioSign$^{TM}$TB를 이용하여 혈청화적 검사를 시행하였다. 결 과: ICT tuberculosis를 사용한 경우, 환자군 56명 및 대조군 47명에 대하여 64.3%의 민감도 및 91.5%의 특이도를 나타내었으며, 폐결핵만 있는 환자군에서 76.5%의 민감도를 보여, 폐외 결핵만 있는 환자군(33.3%)나 두 가지 모두 이환된 군(47.4%)에 비하여 더 높은 민감도를 나타내었다(p=0.039). BioSign$^{TM}$TB를 이용한 경우, 환자군 43명 및 대조군 43 명에 대하여 74.4%의 민감도 및 95.3%의 특이도를 보였으며, 폐질환이 없는 환자군에서는 100%의 특이도를 나타내었다. 환자군중에서 초발환자 및 과거 폐결핵 병력이 있는 환자군 사이에는 민감도에 차이가 없었으며, 공동성 폐결핵 환자와 비공동성 폐결핵 환자사이에 검사상 민감도 차이는 통계적으로 유의하지 않았다(73.3% vs. 69.6%, p>0.05). 결 론: 혈청학적 방법의 하나인 immunochromatographic assay 기구는 높은 특이도와 양성 예측도를 보여 임상적 유용성이 기대되나, 상대적으로 낮은 민감도와 음성 예측도를 고려할 때, 단독 사용보다는 기존 방법과의 상보적 사용이 결핵진단에 더 도움이 될 것으로 생각된다.

• Parasites, Hosts and Diseases
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• 제54권4호
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• pp.393-397
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• 2016

Low parasitemic condition in malaria remains a diagnostic challenge; as the available diagnostic methods failed to detect. Currently, hemozoin (Hz) pigment is gaining attention in the diagnosis of malaria. The major drawback is ease of detection of Hz in routine practice. A pilot study was conducted to evaluate the role of Hz pigment and to compare the performance of quantitative buffy coat assay (QBC) and PCR in such conditions. Clinically suspected cases of malaria were examined by both Giemsa stain and immunochromatographic test (ICT). Samples positive by ICT and negative by Giemsa stain were further examined by nested PCR targeting 18S rRNA and QBC for the presence of malaria parasites and pigments. Thirty blood samples fulfilled the inclusion criteria out of which 23 were Plasmodium vivax (Pv), 4 Plasmodium falciparum (Pf), and 3 mixed (Pv and Pf) by immunochromatographic test. Twenty-one out of 30 (70%) were positive by nested PCR in comparison to 25/30 (83%) by QBC. Samples containing both malaria parasites and Hz pigment by QBC completely showed concordance with the PCR result. However, 61% of total samples containing only Hz pigment were observed positive by PCR. Hz pigment remains an important tool for malaria diagnosis. Identification of leukocytes containing pigments by QBC not only indicates recent malarial infections but also puts light on severity of the disease. QBC assay is a rapid, highly sensitive, and cost-effective method to detect malaria parasites and Hz pigment especially in low parasitemic conditions.

• IMMUNE NETWORK
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• 제21권1호
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• pp.11.1-11.10
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• 2021

Coronavirus causes an infectious disease in various species and crosses the species barriers leading to the outbreak of zoonotic diseases. Due to the respiratory diseases are mainly caused in humans and viruses are replicated and excreted through the respiratory tract, the nasal fluid and sputum are mainly used for diagnosis. Early diagnosis of coronavirus plays an important role in preventing its spread and is essential for quarantine policies. For rapid decision and prompt triage of infected host, the immunochromatographic assay (ICA) has been widely used for point of care testing. However, when the ICA is applied to an expectorated sputum in which antigens are present, the viscosity of sputum interferes with the migration of the antigens on the test strip. To overcome this limitation, it is necessary to use a mucolytic agent without affecting the antigens. In this study, we combined known mucolytic agents to lower the viscosity of sputum and applied that to alpha and beta coronavirus, porcine epidemic diarrhea virus (PEDV) and Middle East respiratory syndrome coronavirus (MERS-CoV), respectively, spiked in sputum to find optimal pretreatment conditions. The pretreatment method using tris(2-carboxyethyl)phosphine (TCEP) and BSA was suitable for ICA diagnosis of sputum samples spiked with PEDV and MERS-CoV. This sensitive assay for the detection of coronavirus in sputum provides an useful information for the diagnosis of pathogen in low respiratory tract.

• Journal of Microbiology and Biotechnology
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• 제26권8호
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• pp.1457-1463
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• 2016

Vibrio anguillarum, a devastating pathogen causing vibriosis among marine fish, is prevailing in worldwide fishery industries and accounts for grievous economic losses. Therefore, a rapid on-site detection and diagnostic technique for this pathogen is in urgent need. In this study, two mouse monoclonal antibodies (MAbs) against V. anguillarum, 6B3-C5 and 8G3-B5, were generated by using hybridoma technology and their isotypes were characterized. MAb 6B3-C5 was chosen as the detector antibody and conjugated with quantum dots. Based on MAb 6B3-C5 labeled with quantum dots, a modified dot blot assay was developed for the on-site determination of V. anguillarum. It was found that the method had no cross-reactivity with other than V. anguillarum bacteria. The detection limit (LOD) for V. anguillarum was 1 × 10³ CFU/ml in cultured bacterial suspension samples, which was a 100-fold higher sensitivity than the reported colloidal gold immunochromatographic test strip. When V. anguillarum was mixed with turbot tissue homogenates, the LOD was 1 × 10³ CFU/ml, suggesting that tissue homogenates did not influence the detection capabilities. Preenrichment with the tissue homogenates for 12 h could raise the LOD up to 1 × 10² CFU/ml, confirming the reliability of the method.

• 한국임상수의학회지
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• 제24권4호
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• pp.588-592
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• 2007

The prevalence of E. coli(K99), Clostridium perfringens and Cryptosporidium parvum on acute diarrhea in suckling Korean native calves was evaluated in the field by a veterinary practice. In diagnosis, fecal samples were directly collected from calves that had diarrhea between 2 and 98 days of age. 40 samples were analyzed in October, 2006 and December, 2006. Clostridium perfringens and Cryptosporidium parvum were detected in 15(37.5%) and 4(10.0%) of the samples from diarrhetic calves, respectively. However, E. coli(K99) was not detected in the samples from diarrhetic calves. There was no significant difference(p>0.05) between October(5, 25.0%) and December(10, 50.0%) in incidence of detected Clostridium perfringens from diarrhetic calves. On the other hand, significant differences (p<0.05) in the detection rate of Clostridium perfringens were found between the within 1 month age and all other age groups. In the detection of Cryptosporidium parvum, there was no significant difference(p<0.05) between October (2, 10.0%) and December(2, 10.0%) in the incidence of detected Cryptosporidium parvum from diarrhetic calves. These results suggest that causative agents of calf diarrhea occurred frequently with Clostridium perfringens infection than E. coli(K99) and Cryptosporidium parvum.

• Annals of Laboratory Medicine
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• 제39권1호
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• pp.50-57
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• 2019

Background: The Automated Fluorescent Immunoassay System (AFIAS) rotavirus assay (Boditech Med Inc., Chuncheon, Korea) is a new rapid antigen test for rotavirus detection. We evaluated the performance of this assay for detecting rotaviruses and their specific genotypes in clinical stool samples. Methods: AFIAS rotavirus assay was performed in 103 rotavirus-positive and 103 rotavirus-negative stool samples (confirmed by both PCR and ELISA), and its results were compared with those of PCR, ELISA, and immunochromatographic assay (ICA). We evaluated diagnostic sensitivity/specificity, the detectability of rotavirus subtypes, lower limit of detection (LLOD), reproducibility, cross-reactivity, and interference of AFIAS rotavirus assay. Results: Based on PCR and ELISA results, diagnostic sensitivity and specificity of the AFIAS rotavirus assay were both 99.0%. LLOD results showed that the AFIAS assay had sensitivity similar to or greater than ICA and ELISA. High reproducibility was confirmed, and no cross-reactivity or interference was detected. This assay could detect genotypes G1P[8], G2P[4], G3P[8], G4P[6], G4P[8], G8P[4], G8P[8], G9P[4], and G9P[8]. Conclusions: The AFIAS rotavirus assay showed high reproducibility, sensitivity, and specificity as well as excellent agreement with ELISA, PCR, and ICA. It detected the most common as well as unusual genotypes of rotavirus prevalent in Korea. It could be a useful onsite assay for rapid, convenient, and cost-effective detection of rotavirus infection.

• 한국동물위생학회지
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• 제32권4호
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• pp.335-341
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• 2009

Canine brucellosis produce abortions and infertility in dogs and is currently diagnosed by serological methods such as rapid slide agglutination test with 2-mercaptoethanol (2-ME RSAT) and immunochromatographic assay (ICA). Bacterial isolation is considered gold standard for Brucella diagnosis and the polymerase chain reaction (PCR) is an alternative method to bacterial isolation. A total of 36 whole blood samples were collected from dogs reared in area of Chuncheon and were subjected to serology (2-ME RSAT and ICA for B. canis, Rose Bengal test and C-ELISA for B. abortus), blood culture and 3 types of PCRs (BSCP31, 16s rRNA, and OMP-2). All blood samples were negative by serology and blood cultures. The BCSP31 and the OMP-2 PCR detected 5 samples were positive whereas the 16S rRNA PCR detected all samples were negative as serological methods and blood culture did. From the results observed in the present study, we conclude that 16S rRNA PCR could be used for direct PCR for canine blood samples.

• Tuberculosis and Respiratory Diseases
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• 제53권4호
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• pp.389-400
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• 2002

배 경 :결핵의 조기치료와 전염방지를 위해서 신속하고 간편한 결핵진단법의 개발이 요구되고 있는 실정에서 결핵균에 특이한 38-kDa단백을 포함하여 금 콘쥬게이트에 결합된 유전자재조합 항원을 혈청과 반응시켜 항결핵 항체를 발견하도록 고안된 카드형태의 혈청학적 진단기법인 Xeniss Rapid TB kit가 결핵의 진단에 유용하게 이용될 수 있는 지를 알아보고자 하였다.방 법 :188명의 결핵환자(폐결핵 177명, 폐외결핵 11명)와 82명의 접촉자, 그리고 57명의 건강한 성인을 대상으로 하였으며, 연구대상자의 혈청을 이용하여 Xeniss Rapid TB kit의 민감도, 특이도, 양성예측율, 그리고 음성예측율을 조사하였다. 결 과 : 전체적인 민감도는 73.9%, 특이도 81.3%, 양상예측율 84.2%, 그리고 음성예측율은 85.8%였다. 진단시점부터 검사시점간의 시간간격에 따라서는 1개월 이내에서 61.5%로 가장 낮고 점차 증가하여 4-6개월 시점에 94.4%로 가장 높았으며 이후 점차 감소하여 12개월 이상 경과한 시점에서는 67.4%의 양성반응율을 보였다. 페외결핵 환자(90.9%)에서는 폐결핵 환자(72.8%)보다 양성반응율이 높았다. 객담도말양성 (76.2 대 68.4%), 방사선 사진상 중증 (79.3 대 63.3%), 공동성 병소(75.7 대 70.0%), 과거 치료력 (76.3 대 73.3%)이 있는 환자군에서 상대적으로 높은 양성반응율을 보였으며, 당뇨병을 동반한 환자군(69.0 대 74.8%)과 노인환자군(68.l 대 100%)에서는 상대적으로 낮은 양성반응율을 보였다. 건강성인군 7.0%, 환자가족군 17.5%에 비해 병원직원군에서 57.9%의 양성반응율을 보여 활동성 결핵환자와 장기간 지속적으로 접촉한 군에서 높은 양성반응율을 보였다. 결 론 : Xeniss Rapid TB kit는 신속하고 간편하며, 민감도와 특이도가 비교적 높고 특히, 폐외결핵에서는 높은 양성반응율을 보여 폐결핵, 폐외결핵, 그리고 감염자의 진단에 보조적 검사법으로 유용하게 이용될 수 있을 것으로 생각된다.