Objective: To access the performance of the Tellgenplex human papillomavirus(HPV) DNA test compared to the polymerase chain reaction-reverse dot blot(PCR-RDB) assay for the HPV genotyping.Methods: Sixty cervical swab ...Objective: To access the performance of the Tellgenplex human papillomavirus(HPV) DNA test compared to the polymerase chain reaction-reverse dot blot(PCR-RDB) assay for the HPV genotyping.Methods: Sixty cervical swab samples were genotyped by the Tellgenplex HPV DNA test and the PCR-RDB assay.The Tellgenplex HPV DNA test and the PCR-RDB assay can detect 26 and 23 HPV genotypes, respectively.Each sample showed discrepancy was genotyped using sequencing.Results: The percent agreement between the two tests ranged from 83.3% to 100.0% according to different genotype.This showed perfect agreement(>0.81) for high-risk HPV genotypes(35, 39, 45, 53, 56, 59, 66, 68, and 82), substantial agreement(>0.65) for high-risk HPV genotypes(16, 18, 33, 52, and 58) and low-risk HPV genotype 43 between the two assays by the kappa analysis.The positive rates of the two assays for frequent HPV genotypes(16, 35, 39, 45, 52, 53, 58, 59, 66, and 82) were not statistically different, but the PCR-RDB assay showed higher positive rates than the Tellgenplex HPV DNA test for HPV genotypes 81(P<0.05).As for more than 10 positive results by the Tellgenplex HPV DNA test and/or the PCR-RDB assay, the PCR-RDB assay showed higher relative sensitivity and specificity than the Tellgenplex HPV DNA test for the three HPV genotypes(16, 52, and 81).All HPV genotypes that can be detected by only the Tellgenplex HPV DNA test(HPV genotypes 44 and 55) were confirmed by sequencing.Conclusions: In conclusion, our results demonstrated that the PCR-RDB assay which can detect more multiple HPV genotypes in each specimen shows higher relative sensitivity and specificity than the Tellgenplex HPV DNA test, which makes it a better option for routine clinical use.展开更多
Objective A PCR-reverse dot blot hybridization （RDBH） assay was developed for rapid detection of rpoB gene mutations in ＇hot mutation region＇ of Mycobacterium tuberculosis （M. tuberculosis）. Methods 12 oligonucl...Objective A PCR-reverse dot blot hybridization （RDBH） assay was developed for rapid detection of rpoB gene mutations in ＇hot mutation region＇ of Mycobacterium tuberculosis （M. tuberculosis）. Methods 12 oligonucleotide probes based on the wild-type and mutant genotype rpoB sequences of M. tuberculosis were designed to screen the most frequent wild-type and mutant genotypes for diagnosing RIF resistance. 300 M. tuberculosis clinical isolates were detected by RDBH, conventional drug-susceptibility testing （DST） and DNA sequencing to evaluate the RDBH assay. Results The sensitivity and specificity of the RDBH assay were 91.2% （165/181） and 98.3% （117/119）, respectively, as compared to DST. When compared with DNA sequencing, the accuracy, positive predictive value （PPV） and negative predictive value （NPV） of the RDBH assay were 97.7% （293/300）, 98.2% （164/167）, and 97.0% （129/133）, respectively. Furthermore, the results indicated that the most common mutations were in codons 531 （48.6%）, 526 （25.4%）, 516 （8.8%）, and 511 （6.6%）, and the combinative mutation rate was 15 （8.3%）. One and two strains of insertion and deletion were found among all strains, respectively. Conclusion Our findings demonstrate that the RDBH assay is a rapid, simple and sensitive method for diagnosing RIF-resistant tuberculosis.展开更多
Plastic resins are known to cause occupational allergies. Therefore, serum-specific antibodies against plastic resins have been widely investigated as diagnostic markers for occupational allergies. In this study, we a...Plastic resins are known to cause occupational allergies. Therefore, serum-specific antibodies against plastic resins have been widely investigated as diagnostic markers for occupational allergies. In this study, we aimed to establish a convenient method for detection of multiple chemical-specific IgG antibodies in human serum based on dot blot analysis. Toluene diisocyanate (TDI), phthalic anhydride (PA), and formaldehyde (FA), which are frequently used to synthesize various resins, reacted well with lysine residues of human serum albumin (HSA) under alkaline conditions. Native polyacrylamide gel electrophoresis (PAGE) showed that the structures of chemical adducts of HSA were different from those of native HSA. Therefore, we performed dot blot assays using these adducts as artificial antigens. Serum samples from workers at plants utilizing plastic resins strongly reacted with TDI, PA, and FA adducts in HSA, while reduced signals were detecting using the serum from unexposed workers. These results suggested that dot blot assays using chemical-HSA adducts as antigens could be beneficial for simultaneously measuring multiple chemical-specific IgGs.展开更多
A set of allele-specific oligonucleotide (ASO) probes used for detecting all 18 β-tha-lassemia mutations found in Chinese was immobilized on two strips of Biodyne C membrane;one containing 7 pairs of oligonucleotide ...A set of allele-specific oligonucleotide (ASO) probes used for detecting all 18 β-tha-lassemia mutations found in Chinese was immobilized on two strips of Biodyne C membrane;one containing 7 pairs of oligonucleotide probes specific for the most commonly found mutant al-leles,and the other containing the remaining 11 pairs of ASO_s specific for the less commonlyfound.The membranes were hybridized with β-globin sequences amplified by polymerase chainreaction (PCR) with biotinylated primers,and then treated with Streptavidin-POD conjugateand substrates for color development.The method has been applied successfully to the detectionof all 18 Chinese β-thalassemia mutations and prenatal diagnosis of two high-risk pregnancies ofβ-thalassemia.Patients with homozygous,heterozygous and compound heterozygous alleles ofthese mutations and normal individuals could be easily distinguished by the present method.Us-ing the immobilized-probe format (reverse dot blot),it was able to screen simultaneously multi-ple β-thalassemia mutations of a DNA sample by performing hybridization only once.This assayis simple,rapid and independent of radio-isotopes and can be appplied for all 18 β-thalassemiamutations so far found in Chinese population.It is considered that this method may be usefulfor gene frequency investigation of large numbers of β-thalassemia DNA samples and used as aroutine method in the clinic laboratory.展开更多
Background:Drug resistant tuberculosis poses a great challenge for tuberculosis control worldwide.Timely determination of drug resistance and effective individual treatment are essential for blocking the transmission ...Background:Drug resistant tuberculosis poses a great challenge for tuberculosis control worldwide.Timely determination of drug resistance and effective individual treatment are essential for blocking the transmission of drug resistant Mycobacterium tuberculosis.We aimed to establish and evaluate the accuracy of a reverse dot blot hybridization(RDBH)assay to simultaneously detect the resistance of four anti-tuberculosis drugs in M tuberculosis isolated in China.Methods:In this study,we applied a RDBH assay to simultaneously detect the resistance of rifampicin(RIF),isoniazid(INH),streptomycin(SM)and ethambutol(EMB)in 320 clinical M.tuberculosis isolates and compared the results to that from phenotypic drug susceptibility testing(DST) and sequencing.The RDBH assay was designed to test up to 42 samples at a time.Pearson's chi-square test was used to compute the statistical measures of the RDBH assay using the phenotypic DST or sequencing as the gold standard method,and Kappa identity test was used to determine the consistency between the RDBH assay and the phenotypic DST or sequencing.Results:The results showed that the concordances between phenotypic DST and RDBH assay were 95%for RIF,92.8%for INH,84.7%for SM,77.2%for EMB and the concordances between sequencing and RDBH assay were 97.8%for RIF,98.8%for INH,99.1%for SM,93.4%for EMB.Compared to the phenotypic DST results,the sensitivity and specificity of the RDBH assay for resistance detection were 92.4 and 98.5%for RIF,90.3 and 97.3%for INH,77.4 and 91.5%for SM,61.4 and 85.7%for EMB,respeaively;compared to sequencing,the sensitivity and specificity of the RDBH assay were 97.7 and 97.9%for RIF,97.9 and 100.0% for INH,97.8 and 1OO.O% for SM,82.6 and 99.1%for EMB,respectively.The turnaround time of the RDBH assay was 7 h for testing 42 samples.Conclusions:Our data suggested that the RDBH assay could serve as a rapid and efficient method for testing the resistance of M. tuberculosis against RIF,INH,SM and EMB,enabling early administration of appropriate treatment regimens to the affected drug resistant tuberculosis patients.展开更多
The recently developed method of in vitro DNA amplification by PCR coupled with radioactive or nonradioactive ASO probe detection provides a simple approach to the prenatal diagnosis of β-thalassemia. However, the DN...The recently developed method of in vitro DNA amplification by PCR coupled with radioactive or nonradioactive ASO probe detection provides a simple approach to the prenatal diagnosis of β-thalassemia. However, the DNA diagnosis of β-thalassemia has remained a complicated problem,because β-thalassemia展开更多
本论文报道一种快捷高效的PCR-dot-blot新方法.该方法利用手动芯片点样仪将微量PCR产物(约100 pg DNA)点样,并采用North2 South Biotin Random Prime DNA Labeling and Detection Kit(PIERCE)完成快速斑点杂交.通过鉴定转基因烟草证...本论文报道一种快捷高效的PCR-dot-blot新方法.该方法利用手动芯片点样仪将微量PCR产物(约100 pg DNA)点样,并采用North2 South Biotin Random Prime DNA Labeling and Detection Kit(PIERCE)完成快速斑点杂交.通过鉴定转基因烟草证明这种方法是可行而有效的.这种新方法节省材料,效率极高,特别适合大批量鉴定转基因植物.展开更多
Dot-blot hybridization was applied in this paper to detect five viruses infecting cucurbitaceous crops, Zuccini yellow mosaic virus （ZYMV）, Watermelon mosaic virus （WMV）, Cucumber mosaic virus （CMV）, Papaya ring...Dot-blot hybridization was applied in this paper to detect five viruses infecting cucurbitaceous crops, Zuccini yellow mosaic virus （ZYMV）, Watermelon mosaic virus （WMV）, Cucumber mosaic virus （CMV）, Papaya ringspot viruswatermelon strain （PRSV-W） and Squash mosaic virus （SqMV）, as a good alternative assay in seed health test and epidemiological and transgenic research. Digoxigenin-labelled cDNA probes of the five viruses were synthesized by PCR with the specific primers and applied in dot-blot hybridization to detect five viruses in crude extraction of the infected leaves. And three SqMV probes of different lengths （0.55, 1.6, and 2.7 kb, respectively） were designed to investigate the effect of hybridization. The results showed that the sensitivity for detecting the crude extraction of infected leaves by ZYMV, WMV, CMV, PRSV-W, and SqMV was down to 1：160, 1：160, 1：320, 1：160, and 1：320, respectively. Three SqMV probes of different length showed no differences on the sensitivity and specificity. The digoxigenin-labelled probes prepared by PCR could be used for accurate and rapid identification of 5 viruses infecting cucurbitaceous crops with good stabilities, sensitivities, specificity, and reproducibilifies.展开更多
Drug sensitivity testing to establish resistance to TB drugs takes many months to arrive at. Public health physicians have difficulties with such an approach due to long wait periods and cannot use it to establish com...Drug sensitivity testing to establish resistance to TB drugs takes many months to arrive at. Public health physicians have difficulties with such an approach due to long wait periods and cannot use it to establish community wide prevalence as a way to understand where resistance may be emerging faster and to limit its spread. The objective of this study was to use the dot-blot hybridization technique in the detection of resistance to rifamycin (RIF) and streptomycin (SM) in South- Western Cameroon and to compare the technique with the routine culture and drug susceptibility testing for detecting resistance in a resource poor country, Cameroon. A hospital-based study was conducted at the Regional hospitals of Buea and Limbe and Tiko Central Clinic. Tuberculosis (TB) patients aged 15 to 50 (mean age: 30.50 ± 8.33 standard deviation) were recruited for the study between December 2006 and April 2007. Cultures from 59 patients were tested for rifampicin and streptomycin sensitivity by the modified proportion method and mutational analysis for rpoB codon 516 and rrs codon 513 was performed by the dot-blot hybridization technique. Of the 59 sputum samples collected (36 were males and 23 were females) came from Buea 19 (32.2%), Limbe 20 (33.9%) and Tiko 20 (33.9%) towns respectively. Amplification for the gene showed that there was (59) 100% amplification with primers used for rpoB genes and 43 (72.9%) amplification with primers used for the rrs gene. Mutational analysis demonstrated that resistance to RIF was common in females (52.1%) than males (41.7%) while 6% of the samples were indeterminate. 12 (20.3%) samples showed phenotypic and genotypic resistance to RIF compared to 34 samples (58.1%) for SM. Phenotypic resistance and genotypic susceptibility were found in 5 (8.5%) RIF and 3 (4.7%) SM compared to phenotypic susceptibility and genotypic resistance that were found in 2 (3.5%) RIF and 3(4.7%) SM. Double mutation on rpoB and rrs genes occurred in 8 (13.6%) DNA samples. Resistance to RIF and SM due to mutations on the rpoB and rrs genes respectively in the SW region was found to be high and comparable to the drug susceptibility testing by 92%, (95% CI: 75.7 - 99.1). The Dot-blot technique will be useful in rapidly assessing the effectiveness of national TB control programs in limiting the spread of resistance strains in Cameroon.展开更多
Dot enzyme-linked immunosorbent assay （dot-ELISA）, indirect ELISA and Westem blot were performed to detect the virulent protease secreted by Vibrio anguillarum which was isolated from the diseased left-eyed flounder...Dot enzyme-linked immunosorbent assay （dot-ELISA）, indirect ELISA and Westem blot were performed to detect the virulent protease secreted by Vibrio anguillarum which was isolated from the diseased left-eyed flounder, Paralichthys olivaceous. Sensitivity results showed that dot-ELISA is a more sensitive, rapid and simple technique for the protease detection. The minimal detectable amount of protease is about 7 pg in the dot-ELISA test, while 7.8 ng in the indirect ELISA and 6.25 ng in the Westem blot respectively. Protease could be detected 2 h after incubation of V. anguillarum in the 2216E liquid medium but enzyme activity was very low at that period. From 6 to 12 h, the amount and enzyme activity of protease increased markedly and reached maximum at stationary phase. Analysis of serum samples periodically collected from the infected flounders showed that after 2 h of infection by V. anguillarum, the pathogenic bacteria could be detected in the blood of the infected flounders but no protease was found. It was 5-6 h after infection that the protease was detected in blood and then the amount increased as infection advanced. Quantitative detection of protease either incubation in the medium or from the blood of infected flounders could be accomplished in virtue of positive controls of quantificational protease standards （＂marker＂） so that the alterations ofprotease secretion both in vitro and in vivo could be understood generally. In addition, the indirect ELISA and dot-ELISA were also performed to detect V. anguillarum cells. Results indicated that the sensitivity of indirect ELISA to bacteria cells is higher than that of the dot-ELISA, and that the minimal detectable amount is approximately 10^4 cell/mL in the indirect ELISA, while 10^5 cell/mL in the dot-ELISA.展开更多
基金supported by the National Nature Science Foundation of China,Grant Number:81400639the Science Foundation for Youth Scientists of the Second People’s Hospital of Guangdong Province of China,Grant Number:YQ2015-002
文摘Objective: To access the performance of the Tellgenplex human papillomavirus(HPV) DNA test compared to the polymerase chain reaction-reverse dot blot(PCR-RDB) assay for the HPV genotyping.Methods: Sixty cervical swab samples were genotyped by the Tellgenplex HPV DNA test and the PCR-RDB assay.The Tellgenplex HPV DNA test and the PCR-RDB assay can detect 26 and 23 HPV genotypes, respectively.Each sample showed discrepancy was genotyped using sequencing.Results: The percent agreement between the two tests ranged from 83.3% to 100.0% according to different genotype.This showed perfect agreement(>0.81) for high-risk HPV genotypes(35, 39, 45, 53, 56, 59, 66, 68, and 82), substantial agreement(>0.65) for high-risk HPV genotypes(16, 18, 33, 52, and 58) and low-risk HPV genotype 43 between the two assays by the kappa analysis.The positive rates of the two assays for frequent HPV genotypes(16, 35, 39, 45, 52, 53, 58, 59, 66, and 82) were not statistically different, but the PCR-RDB assay showed higher positive rates than the Tellgenplex HPV DNA test for HPV genotypes 81(P<0.05).As for more than 10 positive results by the Tellgenplex HPV DNA test and/or the PCR-RDB assay, the PCR-RDB assay showed higher relative sensitivity and specificity than the Tellgenplex HPV DNA test for the three HPV genotypes(16, 52, and 81).All HPV genotypes that can be detected by only the Tellgenplex HPV DNA test(HPV genotypes 44 and 55) were confirmed by sequencing.Conclusions: In conclusion, our results demonstrated that the PCR-RDB assay which can detect more multiple HPV genotypes in each specimen shows higher relative sensitivity and specificity than the Tellgenplex HPV DNA test, which makes it a better option for routine clinical use.
基金funded by the projects 2013ZX10003002-001 and 2013ZX10003006-002-001 of Chinese National Key Program of Mega Infectious Disease of the National 12th Five-Year Plan
文摘Objective A PCR-reverse dot blot hybridization （RDBH） assay was developed for rapid detection of rpoB gene mutations in ＇hot mutation region＇ of Mycobacterium tuberculosis （M. tuberculosis）. Methods 12 oligonucleotide probes based on the wild-type and mutant genotype rpoB sequences of M. tuberculosis were designed to screen the most frequent wild-type and mutant genotypes for diagnosing RIF resistance. 300 M. tuberculosis clinical isolates were detected by RDBH, conventional drug-susceptibility testing （DST） and DNA sequencing to evaluate the RDBH assay. Results The sensitivity and specificity of the RDBH assay were 91.2% （165/181） and 98.3% （117/119）, respectively, as compared to DST. When compared with DNA sequencing, the accuracy, positive predictive value （PPV） and negative predictive value （NPV） of the RDBH assay were 97.7% （293/300）, 98.2% （164/167）, and 97.0% （129/133）, respectively. Furthermore, the results indicated that the most common mutations were in codons 531 （48.6%）, 526 （25.4%）, 516 （8.8%）, and 511 （6.6%）, and the combinative mutation rate was 15 （8.3%）. One and two strains of insertion and deletion were found among all strains, respectively. Conclusion Our findings demonstrate that the RDBH assay is a rapid, simple and sensitive method for diagnosing RIF-resistant tuberculosis.
文摘Plastic resins are known to cause occupational allergies. Therefore, serum-specific antibodies against plastic resins have been widely investigated as diagnostic markers for occupational allergies. In this study, we aimed to establish a convenient method for detection of multiple chemical-specific IgG antibodies in human serum based on dot blot analysis. Toluene diisocyanate (TDI), phthalic anhydride (PA), and formaldehyde (FA), which are frequently used to synthesize various resins, reacted well with lysine residues of human serum albumin (HSA) under alkaline conditions. Native polyacrylamide gel electrophoresis (PAGE) showed that the structures of chemical adducts of HSA were different from those of native HSA. Therefore, we performed dot blot assays using these adducts as artificial antigens. Serum samples from workers at plants utilizing plastic resins strongly reacted with TDI, PA, and FA adducts in HSA, while reduced signals were detecting using the serum from unexposed workers. These results suggested that dot blot assays using chemical-HSA adducts as antigens could be beneficial for simultaneously measuring multiple chemical-specific IgGs.
文摘A set of allele-specific oligonucleotide (ASO) probes used for detecting all 18 β-tha-lassemia mutations found in Chinese was immobilized on two strips of Biodyne C membrane;one containing 7 pairs of oligonucleotide probes specific for the most commonly found mutant al-leles,and the other containing the remaining 11 pairs of ASO_s specific for the less commonlyfound.The membranes were hybridized with β-globin sequences amplified by polymerase chainreaction (PCR) with biotinylated primers,and then treated with Streptavidin-POD conjugateand substrates for color development.The method has been applied successfully to the detectionof all 18 Chinese β-thalassemia mutations and prenatal diagnosis of two high-risk pregnancies ofβ-thalassemia.Patients with homozygous,heterozygous and compound heterozygous alleles ofthese mutations and normal individuals could be easily distinguished by the present method.Us-ing the immobilized-probe format (reverse dot blot),it was able to screen simultaneously multi-ple β-thalassemia mutations of a DNA sample by performing hybridization only once.This assayis simple,rapid and independent of radio-isotopes and can be appplied for all 18 β-thalassemiamutations so far found in Chinese population.It is considered that this method may be usefulfor gene frequency investigation of large numbers of β-thalassemia DNA samples and used as aroutine method in the clinic laboratory.
文摘Background:Drug resistant tuberculosis poses a great challenge for tuberculosis control worldwide.Timely determination of drug resistance and effective individual treatment are essential for blocking the transmission of drug resistant Mycobacterium tuberculosis.We aimed to establish and evaluate the accuracy of a reverse dot blot hybridization(RDBH)assay to simultaneously detect the resistance of four anti-tuberculosis drugs in M tuberculosis isolated in China.Methods:In this study,we applied a RDBH assay to simultaneously detect the resistance of rifampicin(RIF),isoniazid(INH),streptomycin(SM)and ethambutol(EMB)in 320 clinical M.tuberculosis isolates and compared the results to that from phenotypic drug susceptibility testing(DST) and sequencing.The RDBH assay was designed to test up to 42 samples at a time.Pearson's chi-square test was used to compute the statistical measures of the RDBH assay using the phenotypic DST or sequencing as the gold standard method,and Kappa identity test was used to determine the consistency between the RDBH assay and the phenotypic DST or sequencing.Results:The results showed that the concordances between phenotypic DST and RDBH assay were 95%for RIF,92.8%for INH,84.7%for SM,77.2%for EMB and the concordances between sequencing and RDBH assay were 97.8%for RIF,98.8%for INH,99.1%for SM,93.4%for EMB.Compared to the phenotypic DST results,the sensitivity and specificity of the RDBH assay for resistance detection were 92.4 and 98.5%for RIF,90.3 and 97.3%for INH,77.4 and 91.5%for SM,61.4 and 85.7%for EMB,respeaively;compared to sequencing,the sensitivity and specificity of the RDBH assay were 97.7 and 97.9%for RIF,97.9 and 100.0% for INH,97.8 and 1OO.O% for SM,82.6 and 99.1%for EMB,respectively.The turnaround time of the RDBH assay was 7 h for testing 42 samples.Conclusions:Our data suggested that the RDBH assay could serve as a rapid and efficient method for testing the resistance of M. tuberculosis against RIF,INH,SM and EMB,enabling early administration of appropriate treatment regimens to the affected drug resistant tuberculosis patients.
文摘The recently developed method of in vitro DNA amplification by PCR coupled with radioactive or nonradioactive ASO probe detection provides a simple approach to the prenatal diagnosis of β-thalassemia. However, the DNA diagnosis of β-thalassemia has remained a complicated problem,because β-thalassemia
文摘本论文报道一种快捷高效的PCR-dot-blot新方法.该方法利用手动芯片点样仪将微量PCR产物(约100 pg DNA)点样,并采用North2 South Biotin Random Prime DNA Labeling and Detection Kit(PIERCE)完成快速斑点杂交.通过鉴定转基因烟草证明这种方法是可行而有效的.这种新方法节省材料,效率极高,特别适合大批量鉴定转基因植物.
文摘Dot-blot hybridization was applied in this paper to detect five viruses infecting cucurbitaceous crops, Zuccini yellow mosaic virus （ZYMV）, Watermelon mosaic virus （WMV）, Cucumber mosaic virus （CMV）, Papaya ringspot viruswatermelon strain （PRSV-W） and Squash mosaic virus （SqMV）, as a good alternative assay in seed health test and epidemiological and transgenic research. Digoxigenin-labelled cDNA probes of the five viruses were synthesized by PCR with the specific primers and applied in dot-blot hybridization to detect five viruses in crude extraction of the infected leaves. And three SqMV probes of different lengths （0.55, 1.6, and 2.7 kb, respectively） were designed to investigate the effect of hybridization. The results showed that the sensitivity for detecting the crude extraction of infected leaves by ZYMV, WMV, CMV, PRSV-W, and SqMV was down to 1：160, 1：160, 1：320, 1：160, and 1：320, respectively. Three SqMV probes of different length showed no differences on the sensitivity and specificity. The digoxigenin-labelled probes prepared by PCR could be used for accurate and rapid identification of 5 viruses infecting cucurbitaceous crops with good stabilities, sensitivities, specificity, and reproducibilifies.
文摘Drug sensitivity testing to establish resistance to TB drugs takes many months to arrive at. Public health physicians have difficulties with such an approach due to long wait periods and cannot use it to establish community wide prevalence as a way to understand where resistance may be emerging faster and to limit its spread. The objective of this study was to use the dot-blot hybridization technique in the detection of resistance to rifamycin (RIF) and streptomycin (SM) in South- Western Cameroon and to compare the technique with the routine culture and drug susceptibility testing for detecting resistance in a resource poor country, Cameroon. A hospital-based study was conducted at the Regional hospitals of Buea and Limbe and Tiko Central Clinic. Tuberculosis (TB) patients aged 15 to 50 (mean age: 30.50 ± 8.33 standard deviation) were recruited for the study between December 2006 and April 2007. Cultures from 59 patients were tested for rifampicin and streptomycin sensitivity by the modified proportion method and mutational analysis for rpoB codon 516 and rrs codon 513 was performed by the dot-blot hybridization technique. Of the 59 sputum samples collected (36 were males and 23 were females) came from Buea 19 (32.2%), Limbe 20 (33.9%) and Tiko 20 (33.9%) towns respectively. Amplification for the gene showed that there was (59) 100% amplification with primers used for rpoB genes and 43 (72.9%) amplification with primers used for the rrs gene. Mutational analysis demonstrated that resistance to RIF was common in females (52.1%) than males (41.7%) while 6% of the samples were indeterminate. 12 (20.3%) samples showed phenotypic and genotypic resistance to RIF compared to 34 samples (58.1%) for SM. Phenotypic resistance and genotypic susceptibility were found in 5 (8.5%) RIF and 3 (4.7%) SM compared to phenotypic susceptibility and genotypic resistance that were found in 2 (3.5%) RIF and 3(4.7%) SM. Double mutation on rpoB and rrs genes occurred in 8 (13.6%) DNA samples. Resistance to RIF and SM due to mutations on the rpoB and rrs genes respectively in the SW region was found to be high and comparable to the drug susceptibility testing by 92%, (95% CI: 75.7 - 99.1). The Dot-blot technique will be useful in rapidly assessing the effectiveness of national TB control programs in limiting the spread of resistance strains in Cameroon.
文摘Dot enzyme-linked immunosorbent assay （dot-ELISA）, indirect ELISA and Westem blot were performed to detect the virulent protease secreted by Vibrio anguillarum which was isolated from the diseased left-eyed flounder, Paralichthys olivaceous. Sensitivity results showed that dot-ELISA is a more sensitive, rapid and simple technique for the protease detection. The minimal detectable amount of protease is about 7 pg in the dot-ELISA test, while 7.8 ng in the indirect ELISA and 6.25 ng in the Westem blot respectively. Protease could be detected 2 h after incubation of V. anguillarum in the 2216E liquid medium but enzyme activity was very low at that period. From 6 to 12 h, the amount and enzyme activity of protease increased markedly and reached maximum at stationary phase. Analysis of serum samples periodically collected from the infected flounders showed that after 2 h of infection by V. anguillarum, the pathogenic bacteria could be detected in the blood of the infected flounders but no protease was found. It was 5-6 h after infection that the protease was detected in blood and then the amount increased as infection advanced. Quantitative detection of protease either incubation in the medium or from the blood of infected flounders could be accomplished in virtue of positive controls of quantificational protease standards （＂marker＂） so that the alterations ofprotease secretion both in vitro and in vivo could be understood generally. In addition, the indirect ELISA and dot-ELISA were also performed to detect V. anguillarum cells. Results indicated that the sensitivity of indirect ELISA to bacteria cells is higher than that of the dot-ELISA, and that the minimal detectable amount is approximately 10^4 cell/mL in the indirect ELISA, while 10^5 cell/mL in the dot-ELISA.
