Reverse dot blot hybridization assay— An expeditious diagnostic tool for drug resistant TB

Tuberculosis (TB) is one of the leading infectious diseases that is highly transmissible. It is reported to cause approximately 10 million infections and 1.4 million deaths globally in the year of 2019.¹ Prompt detection and treatment of TB are essential to intercept the proliferation of the disease. In the case of drug- resistant TB, failure to detect the resistance of anti TB drugs may give rise to extensively drug- resistant tuberculosis (XDR-TB). Thus, the rapid detection of drug resistance is vital;, however, the current standard drug susceptibility tests (DST) may take up to 12 weeks raising an alarming concern.² A study was done in China by Li Wan et al, on the accuracy of the reverse dot blot hybridization assay (RDBH) for rapidly detecting the resistance of four anti TB drugs (rifampicin (RIF), isoniazid (INH), streptomycin (SM) and ethambutol (EMB)) in mycobacterium tuberculosis (MTB) isolates.³ Continuous...

Alpha Thalassemia Genotypes in Kuwait

Background: The frequency of the alpha thalassemia trait is approximately 40% in the Kuwaiti population, but there has been no comprehensive study of the prevalent alleles. This is a report of patients who were referred for molecular diagnosis over a 20-year period.Methods: This is a retrospective study of the a-globin genotypes obtained in the Hemoglobin Research Laboratory of the Department of Pediatrics, Kuwait University from 1994 to 2015. Genotyping was performed by a combination of PCR, allele-specific oligonucleotide hybridization and reverse dot blot hybridization (Vienna Lab Strip Assay).Results: Four hundred samples were characterized and analyzed from individuals aged <1 month to 80 years, with a median of 6 years from 283 unrelated families. Most (90.8%) were Kuwaiti nationals. The commonest genotype was homozygosity for the polyadenylation-1 mutation (αPA-1α/α PA-1α) in 33.3% of the samples, followed by heterozygosity (αα/α PA-1α) for the same mutation in 32.3%. PA-1 was therefore the most frequent allele (0.59). The frequency of the α0 (--MED) allele was 0.017. Rare alleles that were found in very low frequencies included α0 (--FIL) in a Filipino child, Hb Constant Spring, Hb Adana, and Hb Icaria.Conclusion: There is a wide variety of alpha thalassemia alleles among Kuwaitis, but nondeletional PA-1 is by far the most common cause of the moderate to severe HbH (β4 tetramer) disease phenotype. The α0 (–MED) allele is also encountered, which has implications for premarital counseling, especially for the possibility of having babies with alpha thalassemia major (Barts hydrops fetalis).

Alpha Thalassemia Genotypes in Kuwait

Background: The frequency of alpha thalassemia trait is about 40% in the Kuwaiti population, but there has been no comprehensive study of the prevalent alleles. This is a report of the patients who were referred for molecular diagnosis over a 20-year period. Methods: This is a retrospective study of the a-globin genotypes obtained in the Hemoglobin Research Laboratory of the Department of Pediatrics, Kuwait University from 1994 to 2015. Genotyping was by a combination of PCR, allele-specific oligonucleotide hybridization and reverse dot-blot hybridization (Vienna Lab Strip Assay). Results: Four hundred samples were characterized and analyzed from individuals aged <1 month to 80 years, with a median of 6 years from 283 unrelated families.. Most (90.8%) were Kuwaiti nationals. The common genotype was homozygosity for the polyadenylation-1 mutation (α PA-1 α/α PA-1 α) in 33.3%, followed by heterozygosity (αα/α PA-1 α) for the same mutation in 32.3%. The PA-1 was therefore the most frequent allele (0.59). The frequency of the α 0 , – MED was 0.017. Rare alleles that were found in very low frequencies included the α 0 (-- FIL ) in a Filipino child, Hb Constant Spring, Hb Adana, and Hb Icaria. Conclusion : There is a wide variety of alpha thalassemia alleles among Kuwaitis, but the nondeletional PA-1 is by far the most common cause of moderate to severe HbH (β4 tetramer), disease phenotype. The α 0 (– MED ) allele is also encountered, which has implications for pre-marital counselling especially the possibility of having babies with alpha thalassemia major (Barts hydrops fetalis).

Alpha Thalassemia Genotypes in Kuwait

Background: The frequency of alpha thalassemia trait is about 40% in the Kuwaiti population, but there has been no comprehensive study of the prevalent alleles. This is a report of the patients who were referred for molecular diagnosis over a 20-year period.Methods: This is a retrospective study of the a-globin genotypes obtained in the Hemoglobin Research Laboratory of the Department of Pediatrics, Kuwait University from 1994 to 2015. Genotyping was by a combination of PCR, allele-specific oligonucleotide hybridization and reverse dot-blot hybridization (Vienna Lab Strip Assay).Results: Four hundred samples were characterized and analyzed from individuals aged <1 month to 80 years, with a median of 6 years from 283 unrelated families.. Most (90.8%) were Kuwaiti nationals. The common genotype was homozygosity for the polyadenylation-1 mutation (αPA-1α/α PA-1α) in 33.3%, followed by heterozygosity (αα/α PA-1α) for the same mutation in 32.3%. The PA-1 was therefore the most frequent allele (0.59). The frequency of the α0, –MED was 0.017. Rare alleles that were found in very low frequencies included the α0 (--FIL) in a Filipino child, Hb Constant Spring, Hb Adana, and Hb Icaria.Conclusion: There is a wide variety of alpha thalassemia alleles among Kuwaitis, but the nondeletional PA-1 is by far the most common cause of moderate to severe HbH (β4 tetramer), disease phenotype. The α0 (–MED) allele is also encountered, which has implications for pre-marital counselling especially the possibility of having babies with alpha thalassemia major (Barts hydrops fetalis).

Development of a DNA Macroarray for the Detection and Identification of Fungal Pathogens Causing Decline of Young Grapevines

Young vine decline (YVD) is a complex disease caused by at least 51 different fungi and responsible for important economic losses to the grapevine industry worldwide. YVD fungi are known to occur in planting material. Hence, detection prior to planting is critical to assure longevity of newly established vineyards. A DNA macroarray based on reverse dot-blot hybridization containing 102 oligonucleotides complementary to portions of the β-tubulin region was developed for detection of YVD fungi. Specificity of the array was first evaluated against 138 pure fungal cultures representing 72 different taxa from nine genera, including 37 YVD species. In total, 61 species, including 34 YVD pathogens, were detected and identified by the array. The detection limit of the array was below 0.1 pg of genomic DNA. The array was validated against artificially inoculated canes and soil and commercial planting material, with the latter showing a high incidence of YVD fungi in nursery plants otherwise not detected by traditional plating and culturing. This DNA array proved to be a rapid and specific tool to simultaneously detect and identify most YVD fungi in a single test, which has the potential to be used in commercial diagnostics or by the grapevine nursery industry to determine the health status of the planting material.