• Research in Plant Disease
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• v.11 no.2
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• pp.135-139
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• 2005

Bacterial canker of Japanese apricot (Prunus mume Sieb. et Zucc.) was found in all orchards located at southern area of Korea. Typical symptoms were characterized by dark spots formed on fruits, brown lesions on leaves, and bacterial exudate oozed out of the cracked bark of diseased tree. Thirty-eight isolates from 16 different areas were identified on the basis of biochemical and physiological characteristics (LOPAT and GATTa test) and also on the basis of 165 rDNA and ITS sequences. Pathogenicity tests confirmed that bacterial canker of Japanese apricot in Korea is caused by Pseudomonas syringae pv. morsprunorum.

• The Plant Pathology Journal
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• v.39 no.1
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• pp.88-107
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• 2023

In the present investigation, bacterial isolates from infected apple trees causing apple canker during winter were studied in the northern Gyeongbuk Province, Korea. The pathogen was identified as Pseudomonas syringae pv. syringae (Pss) through various physiological and biochemical characterization assays such as BIOLOG, gas chromatography of fatty acid methyl esters, and 16S rRNA. Bioassays for the production of phytotoxins were positive for syringopeptin and syringomycin against Bacillus megaterium and Geotrichum candidum, respectively. The polymerase chain reaction (PCR) method enabled the detection of toxin-producing genes, syrB1, and sypB in Pss. The differentiation of strains was performed using LOPAT and GATTa tests. Pss further exhibited ice nucleation activity (INA) at a temperature of -0.7℃, indicating an INA⁺ bacterium. The ice-nucleating temperature was -4.7℃ for a non-treated control (sterilized distilled water), whereas it was -9.6℃ for an INA^- bacterium Escherichia coli TOP10. These methods detected pathogenic strains from apple orchards. Pss might exist in an apple tree during ice injury, and it secretes a toxin that makes leaves yellow and cause canker symptoms. Until now, Korea has not developed antibiotics targeting Pss. Therefore, it is necessary to develop effective disease control to combat Pss in apple orchards. Pathogenicity test on apple leaves and stems showed canker symptoms. The pathogenic bacterium was re-isolated from symptomatic plant tissue and confirmed as original isolates by 16S rRNA. Repetitive element sequence-based PCR and enterobacterial repetitive intergenic consensus PCR primers revealed different genetic profiles within P. syringae pathovars. High antibiotic susceptibility results showed the misreading of mRNA caused by streptomycin and oxytetracycline.

• Parasites, Hosts and Diseases
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• v.54 no.2
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• pp.191-195
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• 2016

The aim of this study was to evaluate different methods for Trichomonas vaginalis diagnosis during pregnancy in order to prevent maternal and perinatal complications. A total of 386 vaginal exudates from pregnant women were analyzed. T. vaginalis was investigated by 3 types of microscopic examinations direct wet mount with physiologic saline solution, prolonged May-Grunwald Giemsa (MGG) staining, and wet mount with sodium-acetate-formalin (SAF)/methylene blue method. PCR for 18S rRNA gene as well as culture in liquid medium were performed. The sensitivity and specificity of the microscopic examinations were evaluated considering the culture media positivity or the PCR techniques as gold standard. The frequency of T. vaginalis infection was 6.2% by culture and/or PCR, 5.2% by PCR, 4.7% by culture, 3.1% by SAF/methylene blue method and 2.8% by direct wet smear and prolonged MGG staining. The sensitivities were 83.3%, 75.0%, 50.0%, and 45.8% for PCR, culture, SAF/methylene blue method, and direct wet smear-prolonged MGG staining, respectively. The specificity was 100% for all the assessed methods. Microscopic examinations showed low sensitivity, mainly in asymptomatic pregnant patients. It is necessary to improve the detection of T. vaginalis using combined methods providing higher sensitivity, such as culture and PCR, mainly in asymptomatic pregnant patients, in order to prevent maternal and perinatal complications.

• Parasites, Hosts and Diseases
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• v.48 no.1
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• pp.61-65
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• 2010

The objectives of this study were to conduct a prevalence survey of trichomoniasis in pregnant women and to evaluate the utility of different methods for its diagnosis. A total of 597 vaginal exudates from pregnant women who were examined at the Hospital de Clinicas in Buenos Aires, Argentina from 1 August 2005 to 31 January 2007, were prospectively and consecutively evaluated. The investigation of Trichomonas vaginalis was made by different microscopic examinations, and culture on liquid medium. The sensitivity and specificity of the microscopic examinations were assessed considering culture on liquid medium as the "gold standard". The prevalence of T. vaginalis obtained by culture on liquid medium was 4.0% (24/597). The prevalence of T. vaginalis obtained by direct wet smear, prolonged May-Grunwald Giemsa staining, and sodium acetate-formalin (SAF)/methylene blue staining-fixing technique was 1.8%, 2.3% and 2.5%, respectively. The sensitivity of the direct wet smear was 45.8%, that of the prolonged May-Grunwald Giemsa staining was 58.3%, and that of the SAF/methylene blue method was 62.5%. Considering the 3 microscopic examinations altogether, the sensitivity rose to 66.7% and the specificity was 100% for all of them. This is the first time that the prevalence data of T. vaginalis by culture in pregnant women are published in Argentina. Due to the low sensitivity obtained by microscopy in asymptomatic pregnant women, the use of the liquid medium is recommended during pregnancy, in order to provide an early diagnosis and treatment.