• Korean Journal of Veterinary Research
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• v.39 no.2
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• pp.311-317
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• 1999

Pathogenic effects of 29 different porcine reproductive and respiratory syndrome(PRRS) virus isolates were investigated in swine tracheal ring(STR) cultures by examining their effects on the ciliary activity of STR. Inhibition of ciliary movement and destruction of the tracheal epithelium were seen between 72 and 96 hours postinoculation(PI). Virus replication was demonstrated by examining viral infectivity of the supernatants from the STR cultures. PRRS virus antigen in macrophages was detected by a streptavidin-biotin complex(ABC) immunoperoxidase method. Of the 29 PRRS virus isolates, 8 isolates were classified into pathogenic, and the remaining 21 isolates were determined as mildly pathogenic or apathogenic viruses. These results suggest that STR examination may be used as a method for predicting pathogenic variability of PRRS virus isolates.

• Korean Journal of Veterinary Service
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• v.20 no.3
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• pp.281-288
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• 1997

Streptococcus suis has been identified as a major cause of contagious disease in pigs Ithas been isolated worldwide from pigs suffering from meningitis, bronchopneumonia, polyserositis, polyarthritis and septicemia. Two hundred and fifty-five lung samples of slaughter pigs with gross lung lesions were collected from Jan. to Dec. 1995 in southern Chonnam area. Isolation of S suis were tested by biochemical, serological methods and antimicrobial susceptibility. The results were summerrized as follows ; 1. S suis was Isolated from 30 of 254 pneumonic lungs, 14 Isolates were isolated only, 12 were isolated with p. multocida and 4 were isolated with unidentified Gram positive cocci. 2. In biochemical characteristics studies, all isolates were not grown in 6.5% NaCl medium, and most isolates utilized L-leucine-2-naphtylamide and trehalose, didn't utilize sorbitol, ribose and L-arabinose. 3. In slide agglutination test, 6(20%) Isolates were classified as serotype 2, 4(13.3%) isolates were as serotype l/2, 16, 2 and 2(6.6%) were as serotype 1, 4, 13. 4. S suis isolates showed marked susceptibility to amoxicillin, oxacillin, cephalothin and cepoferazone and high resistance to kanamycin, streptomycin, tetracycline and erythromycin.

• Korean Journal of Environmental Agriculture
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• v.34 no.3
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• pp.238-243
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• 2015

BACKGROUND: Yeasts associated with fleabane flowers were identified using isolation methods previously applied in yeast biotechnology. A culture-based approach was required for isolation of many yeast strains associated with fleabane. METHODS AND RESULTS: We spread homogenized fleabane flowers onto GPY medium containing chloramphenicol, streptomycin, Triton X-100, and L-sorbose. We isolated 79 yeast strains from the flowers of wild fleabane, and identified the yeasts via phylogenetic analysis of isolates from agar plates. The yeast species included 39 isolates of Aureobasidium pullulans, 17 of the genus Candida, 14 of the genus Rhodosporidium, 6 of the genus Cryptococcus, and 3 of the genus Rhodotorula. CONCLUSION: Yeast isolates associated with fleabane flowers included A. pullulans (39 isolates) and other yeast species (40 isolates). Such yeast isolates may have biotechnological potential.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.2
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• pp.94-101
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• 2016

Acinetobacter species isolates are important opportunistic pathogens and commonly implicated in nosocomial infections. The therapeutic options for treatment of the bacterial infections are limited because the bacteria isolates are usually multidrug resistant (MDR). In the current study, we investigated various carbapenemase genes in 68 Acinetobacter species isolates. Antimicrobial susceptibilities were tested using the disk diffusion method. Screening of carbapenemase genes was performed via multiplex PCR. In addition, PCR and DNA sequencing were used to identify the carbapenemase genes. Repetitive extragenic palindromic-PCR (REP-PCR) was also performed to assess the clonality of isolates. In our study, A. baumannii isolates were highly resistant to all agents tested while all non-A. baumannii isolates were susceptible to all agents tested, with the exception of aztreonam and cefotaxime. All 51 A. baumannii isolates contained the $bla_{OXA-51}$ gene and 37 (72.5%) isolates also harbored the $bla_{OXA-23}$ gene. In addition, 39 MDR A. baumannii isolates were identified in our study and 37 isolates contained the $bla_{OXA-23}$ gene. The 37 MDR strains harboring $bla_{OXA-23}$ showed type I (n=22) or type II (n=15) banding patterns on their REP-PCR profiles. Our results suggest clonal relation and horizontal spreading of MDR A. baumannii isolates containing the $bla_{OXA-23}$ gene at the hospital located in Daejeon. Continuous investigation of antimicrobial resistant determinants and monitoring emergence and dissemination of MDR isolates is required to prevent and control infection and colonization of MDR A. baumannii isolates.

• Korean journal of applied entomology
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• v.23 no.2 s.59
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• pp.89-95
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• 1984

Sixty isolates of Dendrophoma obscurans isolated from 19 important strawberry growing areas of Korea were tested in vitro for resistance to thiophanate-methyl and iprodione. Naturally-occurring thiophanate-methyl-resistant isolates were about 43 percents of isolates tested, whereas iprodione-resistant isolates were 10 percents. All these resistant isolates except SU 1 and SU 2, which were highly resistant to thiophanate-methyl, showed a week level of resistance. Iprodione-resistant isolates were readily obtained in vitro, when mycelial disk of the fungus was incubated on PDA media containing iprodione at the concentrations of $1{\mu}g/ml\;and\;10{\mu}g/ml$, but no thiophanate-methyl-resistant isolate from the mycelia with or without UV irradiation. All these artificially-obtained iprodione-resistant isolates were showed a high degree of resistance. On the strawberry leaves, thiophanate-methyl and iprodione were no longer effective to all resistant isolates at the recommended concentration, and the protective value to highly resistant isolates was much less than that of weakly resistant isolates. Isolates resistant to thiophanate-methyl were also resistant to benomyl but iprodione-resistant isolates did not show cross-resistance to thiophanate-methyl, benomyl, captan and zineb. Captan controlled both thiophanate methyl-resistant and iprodione-resistant isolates as effectively as sensitive isolates.

• Biomedical Science Letters
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• v.19 no.2
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• pp.132-141
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• 2013

Mycobacterium isolates were retrospectively identified, antibiotics susceptibility test results and basic clinical data were analyzed for the 715, excepted 308 in 1,023 specimens, from a mycobacterial laboratory at a tertiary care hospital from September 2002 to December 2008. Their male to female ratio was 1.12 to 1 (379 male, 336 female). The median age of study population was 47 years (range from 10 to 93 years). Distribution of Mycobacterium species was 90.1% of total were isolates Mycobacterium tuberculosis, and 9.9% of the total non-tuberculosis Mycobacterium isolated, and Among nontuberculosis Mycobacterium isolates, 60.6% were Mycobacterium avium complex, 14.1% were isolates Mycobacterium abscessus, and 12.7% were isolates Mycobacterium intracellulare. Among 526 Mycobacterium tuberculosis isolates, 81.7% isolates were susceptible to first line antibiotics, 18.3% were resistant to one or more antibiotics. Non-tuberculosis Mycobacterium isolates, all were resistant to two or more antibiotics. Multi-antibiotic resistant tuberculosis rate was show 10.2% of total specimens. Isolated Mycobacterium species, 19.2% were multi-antibiotic resistant tuberculosis, and the rate of nontuberculosis Mycobacterium resistant to isoniazid and rifampin was very highly 84.5%. Thus among acid fast bacilli culture positive cases, Mycobacterium tuberculosis and non-tuberculosis Mycobacterium were must exactly identification and antibiotic sensitivity test. It was considered to help to select of the antibiotic in preventive medicine.

• Parasites, Hosts and Diseases
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• v.47 no.3
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• pp.259-264
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• 2009

Genetic polymorphisms of encoding antigen B2 gene (AgB2) in Echinococcus granulosus were studied using PCR-RFLP and DNA sequencing among 20 Egyptian isolates. Five isolates from different host origins (humans, camels, pigs, and sheep) were collected and used. All examined isolates of each host group gave very similar patterns of PCR-RFLP after restriction enzyme digestion with Alul, with the gene size of approximately 140 bp and 240 bp for sheep and human isolates, and approximately 150 bp and 250 bp for pig and camel isolates. No digestion pattern was obtained after incubation of all studied isolates with EcoRI. These results reveal high intra-group homogeneity. DNA sequence analysis highlighted that human infecting strain showed 100% identity with respect to sheep infecting isolate, 96% and 99% with pig and camel infecting isolates, respectively.

• The Plant Pathology Journal
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• v.22 no.1
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• pp.28-35
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• 2006

Virulence and genetic diversity were studied using 21 isolates of Sclerospora graminicola, the pearl millet downy mildew pathogen collected from major pearl millet growing areas of India. Variability for virulence was determined by inoculating a set of 10 differential hosts with the S. graminicola isolates in a greenhouse. The isolates varied for latent period (6.4 to 11 days), disease incidence (0 to $98\%$), virulence index (0 to 18.7) and oospore-production potential (1 to 4). Among the 21 isolates, Sg 139 (Rajasthan) was the most virulent and Sg 110 (Tamil Nadu) the least virulent. Based on virulence index (disease incidence$\time$slatent $period^{-1}$), the 21 isolates were classified into eight virulence groups. Genetic diversity among isolates was studied using AFLP markers. Based on similarity index of banding pattern, the 21 isolates were clustered into eight genotypic groups. The AFLP groupings, however, did not match with that of the virulence groupings, and these two were found independent. The isolate Sg 139 that remained distinct in both pathogenic and genetic groupings indicated its highly virulent nature. Implications of these results in downy mildew resistance breeding are discussed.

• The Plant Pathology Journal
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• v.25 no.4
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• pp.317-321
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• 2009

Sensitivity to the new carboxylic acid amide fungicide, mandipropamid, of Phytophthora capsici causing pepper Phytophthora blight was determined on 187 isolates collected in Korea over 3 years, from 2005 to 2007. All isolates were sensitive to mandipropamid, with $EC_{30}$ values for growth of mycelia ranging from 0.001 to $0.037\;{\mu}g/ml$. Among the isolates, 147 (79.0%) isolates were sensitive to metalaxyl, whereas others were resistant to this fungicide. Mandipropamid had the same effect on mycelium growth of both metalaxyl-sensitive and metalaxyl-resistant isolates, indicating an absence of cross-resistance between these two fungicides. Comparison of the sensitivities of P. capsici isolates showed a positive correlation between sensitivity to mandipropamid and dimethomorph ($r^2$=0.8533). The results of this study indicate that there is no evidence for development of resistance to mandipropamid in this population of P. capsici isolates collected in Korea.

• Journal of Microbiology and Biotechnology
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• v.21 no.12
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• pp.1228-1235
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• 2011

We compared the gene expression among four clinical and five environmental V. vulnificus isolates, using a cDNA microarray containing 131 genes possibly associated with pathogenicity, transport, signal transduction, and gene regulations in the pathogen. cDNAs from total RNAs of these isolates were hybridized into the cDNA microarray using the cDNA of the wild-type strain MO6-24/O as a reference. We focused on selecting differentially expressed (DE) genes between clinical and environmental isolates using a modified t-statistic. We could detect two statistically significant DE genes between virulent isolates and less-virulent isolates with a marginal statistical significance (p-value of 0.008). These were genes putatively encoding pilin and adenlyate cylase. Real time-PCR confirmed that these two selected genes transcribed in significantly higher levels in virulent isolates than in less-virulent isolates. Mutants with lesions in the gene encoding pilin showed significantly higher $LD_{50}$ values than that of wild type.