Laboratory Diagnostic Tools for Syphilis: Current Status and Future Prospects

With the increasing number of patients infected with syphilis in the past 20 years, early diagnosis and early treatment are essential to decline syphilis prevalence. Owing to its diverse manifestations, which may occur in other infections, the disease often makes clinicians confused. Therefore, a sensitive method for detecting T. pallidum is fundamental for the prompt diagnosis of syphilis. Morphological observation, immunohistochemical assay, rabbit infectivity test, serologic tests, and nucleic acid amplification assays have been applied to the diagnosis of syphilis. Morphological observation, including dark-field microscopy, silver-staining, and direct fluorescent antibody staining for T. pallidum, can be used as a direct detection method for chancre specimens in primary syphilis. Immunohistochemistry is a highly sensitive and specific assay, especially in the lesion biopsies from secondary syphilis. Rabbit infectivity test is considered as a sensitive and reliable method for detecting T. pallidum in clinical samples and used as a historical standard for the diagnosis of syphilis. Serologic tests for syphilis are widely adopted using non-treponemal or treponemal tests by either the traditional or reverse algorithm and remain the gold standard in the diagnosis of syphilis patients. In addition, nucleic acid amplification assay is capable of detecting T. pallidum DNA in the samples from patients with syphilis. Notably, PCR is probably a promising method but remains to be further improved. All of the methods mentioned above play important roles in various stages of syphilis. This review aims to provide a summary of the performance characteristics of detection methods for syphilis.

Uji Infektifitas dan Efektifitas Rhizobia sp. terhadap Tanaman Kedelai di Rumah Kasa pada Tanah Ultisol dengan pH yang Berbeda

Rhizobia fixed nitrogen from the air and supplied legume and effected to soil fertility. The research was conducted in May 2017 until November at Soil Biology Laboratory and Screen House of Agriculture Faculty University of Sumatera Utara. This research was carried out with 2 stages: growth test at various pH with isolate tested (TJA 1, TJA 2, TJA 3, BGR 1, BGR 2, BGR 3, BGR 4, BALAI 1, BALAI 2, BALAI 3, LP 1, LP 2, LP 3, LP 4 and LAB) and the infectivity test and the effectivity of Rhizobia. The research used Randomized Block Design with 2 treatment: Lime (Without Lime and Lime 1 x Aldd) and Isolate Rhizobia (TJA 1, TJA 3, BGR 1, BGR 3, BGR 4, BALAI 2, BALAI 3, LP 1, LP 2, LP 4 and LAB). The application of Rhizobia’s isolate BGR 3 showed the infektively with root nodule amount criteria(124,00). The isolate Rhizobia’s BGR 3 effectively increased N plant level and N absorption (3,80 %; 31,08mg/plant). Application of isolate Rhizobia was not able to increase the level of P plants and P plant uptake. The best interaction was shown (Plant height 85.00 cm, stem diameter 3.93 mm, root nodule 127.50, N level of 3.80%, N absorption 30.16 mg / plant) by treatment of BGR 3 and Lime 1 x Aldd.

Molecular diversity of stress-tolerant PGPR rhizobia nodulating clusterbean (Cyamopsis tetragonoloba L.) grown in hyper-arid zone of Rajasthan

A total of 81 rhizobia were retrieved from nodules of clusterbean grown in hyper-arid zone of Rajasthan. Twenty one rhizobial isolates showed combined drought tolerance of 40% concentration of polyethylene glycol 6000 and temperature tolerance at 45°C. All the stress-tolerant rhizobia were authenticated by plant infectivity test and further showed the presence of nitrogen fixation nifH gene. Most of the stress-tolerant rhizobia harbour multiple PGPR traits. The molecular diversity among stress-tolerant rhizobia was accomplished through RFLP of 16S rDNA using restriction enzymes MspI and HaeIII. Dendrogram data showed that all 21 isolates were distributed into two major clusters. Total of 20 genotypes were formed but 13 biotypes were constituted at 80% level of similarity. Out of these, biotype 10 was found to be the most prevalent biotype of hyper-arid zone. Moreover, isolates from same nodule were not 100% similar. It indicated that vast diversity was present among stress-tolerant clusterbean rhizobial isolates.

Molecular diversity of berseem (Trifolium alexandrinum L.) rhizobia isolated from Haryana soil

Total of forty rhizobia were isolated from nodule samples of berseem crop from farmers’ fields representing 17 villages of Haryana state, India. All the isolates were Gram-negative small rods and authenticated as rhizobia by plant infectivity test. Twenty nine rhizobial isolates on the basis of good nodulation characteristics were further selected for molecular diversity study. The amplified PCR product of genomic DNA of all the 29 rhizobia was digested with HaeIII restriction enzyme which resulted in polymorphic bands. Dendrogram based on RFLP of 16S rDNA profiles showed that all the 29 isolates were distributed in two major groups with different subgroups. A total of 7 biotypes were formed at 80% level of similarity by considering each cluster as rhizobial biotype, and out of these, two biotypes (1^st and 5^th) were found to be most prevalent in all the three districts studied. So, the rhizobia belonging to these two biotypes may be used as biofertilizer in these three districts. Moreover, isolates from same nodule were not 100% similar. It indicated that considerable diversity was present among berseem rhizobial isolates

Canadian Public Health Laboratory Network Laboratory Guidelines for the Use of Direct Tests to Detect Syphilis in Canada

Treponema pallidumsubsp.pallidumand/or its nucleic acid can be detected by various methods such as microscopy, rabbit infectivity test or polymerase chain reaction (PCR) tests. The rabbit infectivity test forT. pallidum, although very sensitive, has been discontinued from most laboratories due to ethical issues related to the need for animal inoculation with liveT. pallidum, the technically demanding procedure and long turnaround time for results, thus making it impractical for routine diagnostic use. Dark-field and phase-contrast microscopy are still useful at clinic- or hospital-based laboratories for near-bedside detection ofT. pallidumin genital, skin or mucous lesions although their availability is decreasing. The lack of reliable and specific anti-T. pallidumantibodies and its inferior sensitivity to PCR may explain why the direct fluorescent antibody test forT. pallidumis not widely available for clinical use. Immunohistochemical staining forT. pallidumalso depends on the availability of specific antibodies, and the method is only applicable for histopathological examination of biopsy and autopsy specimens necessitating an invasive specimen collection approach. With recent advances in molecular diagnostics, PCR is considered to be the most reliable, versatile and practical for laboratories to implement. In addition to being an objective and sensitive test for direct detection ofTreponema pallidumsubsp. pallidumDNA in skin and mucous membrane lesions, the resulting PCR amplicons from selected gene targets can be further characterized for antimicrobial (macrolide) susceptibility testing, strain typing and identification ofT. pallidumsubspecies.

DIAGNOSIS PENYAKIT MOSAIK (SOYBEAN MOSAIC VIRUS) TERBAWA BENIH KEDELAI

Soybean mosaic disease is wide spread throughout soybean-growing countries. Incidence of this disease in East Java is caused by Soybean mosaic virus (SMV) and cowpea mild mottle virus (CMMV). This aim of study was to find the etiology of disease at 14-28 days after planting (dap) on soybean. Research was done by observing visual symptoms. Visual symptoms confirmed by infectivity test, serology assay,electron microscopy (EM) and molecular detection. Results from experiment indicated that soybean plants (14-28 dap) with symptom could be detected in infectivity test. Mechanical inoculation with symptomatic leaf extracts produced local lessions on Chenopodium amaranticolor. Positive results were obtained for Madiun, Ngawi, and Magetan samples when tested against antiserum of SMV in serological assay, however Ponorogo samples were not detected by serological assay. Electron microscopy was also done for the selected sample to confirm the result of positive results. In EM observations, characteristic filamentous particles with modal length close to 900 nm were observed in samples infected with SMV. We detected an array of amplification products of expected size 1385 bp fragment of cylindrical inclusion gene from Madiun, Ngawi, and Magetan isolates in former fields, but not detected in Ponorogo isolate. This result showed the existence of SMV of soybean seed transmission at 14-28 dap in Madiun, Magetan and Ngawi.