• Journal of the Korean Society of Tobacco Science
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• v.31 no.2
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• pp.69-74
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• 2009

Potato Virus Y (PVY), PVY-vein necrosis strain, causes severe damage at growth, yield and leaf quality on flue-cured tobacco in Korea. The development of PVY resistant flue-cured varieties without quality deterioration is therefore urgently desired. The flue-cured tobacco, KF120 (Korea Flue-cured 120), was a male-sterile (ms) $F_1$ hybrid derived from the cross between msKF117 and KF0007-7. msKF117 was developed from the cross of NC82 with N. africana and KF0007-7 was developed from the cross of KF117 with NC82. The agronomic characteristics and disease resistance of KF120 was evaluated during 2006-2007 field performance test. It showed better growth characteristics and yield performance than standard cultivar KF109. It had 2 more leaves per plant, flowered 2 days later than KF109. The yield of cured leaf of KF120 was increased by about 5% compared to KF109. The chemical composition and physical properties of the cured leaf of KF120 were as much acceptable as those of KF109. KF120 showed high resistance to PVY compared to KF109. It showed a similar mode of resistance to bacterial wilt and black shank as was found in KF109.

• Korean Journal of Poultry Science
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• v.49 no.2
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• pp.69-77
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• 2022

Antimicrobial peptides (AMPs) play an important role in innate immunity against pathogenic infections. AMPs exterminate pathogenic bacteria by disrupting cell membranes or inhibiting intracellular molecules. NK-2, first identified in pigs and derived from NK-lysin, has antimicrobial effects against bacteria and parasites. In this study, chimeric peptides (cpNK) of chicken and pig NK-2 and cpNK-derived peptides (cpNK-a1 and cpNK-a2) were synthesized, and their antimicrobial effects against various pathogenic bacteria such as Escherichia coli, Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA) were investigated. The structure of chimeric peptides from chicken and pig NK-2, cpNK, include α-helix like NK-2 and peptide net charge was +9 like porcine NK-2. The cpNK peptide showed powerful bactericidal effects against most bacterial species, including MRSA, especially against gram-negative bacteria. Furthermore, cpNK-derived short peptides, cpNK-a1 and a2 also showed bactericidal activity, but the effects were weaker than those of cpNK. Therefore, we conclude that cpNK- and cpNK-derived short peptides have the potential to be used as antibiotic alternatives.

• Tuberculosis and Respiratory Diseases
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• v.47 no.2
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• pp.184-194
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• 1999

Backgrounds : The advent of penicillin has led to the marked reduction in the mortality from pneumococcal bacteremia, however, the mortality is still relatively high in this post-antibiotic era. Actually the prevalence of infection due to penicillin-resistant penumococci is increasing worldwide, and it is especially high in Korea due to irrelevant use of antibiotics. So, the high mortality of pneumococcal sepsis might be related to the emergence of penicillin-resistant strains, however, many other antibiotics, which eradicate pneumococci effectively, are available in these days. This has led us to suspect the role of penicillin-resistance in the high mortality rate. In this study, we evaluated the effect of penicillin resistance on the mortality of patients with penumococcal bacte remia. Methods: The study population consisted of 50 adult patients with penumococcal bacteremia who were admitted between Jan, 1990 and July, 1997. Medical records were analyzed retrospectively. Results: Most of the patients (96%) had underlying diseases. The most common local disease associated with pneumococcal bacteremia was pneumonia (42%), which was followed by spontaneous bacterial peritonitis (14%), cholangitis (10%), meningitis (8%), liver abscess (4%), pharyngotonsillitis (4%), sinusitis (2%) and cellulitis (2%). While the overall case-fatality rate in this study was 24%, it was higher when peumococcal bacteremia was associated with pneumonia (42%) or meningitis (50%). The rate of penicillin resistance was 40%, which was increased rapidly from 1991. The rate of penicillin resistance was significantly higher in patients with the history of recent antibiotics use and hospitalization within 3 months respectively. The clinical manifestations, that is, age, severity of underlying diseases, nosocomial infection, associated local diseases, and the presence of shock or acute renal failure were not statistically different between the patients with penicillin-resistant and -sensitive pneumococcal bacteremia. The mortality of patients infected with penicillin-resistant pneumococci was not statistically different from those with penicillin-sensitive pneumococcal bacteremia. Conclusion: Penicillin resistance is not associated with high mortality in adult patients with pneumococcal bacteremia. As the overall mortality is high, active penumococcal vaccination is recommended in patients with high risk of infection.

• Journal of Microbiology
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• v.44 no.6
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• pp.660-664
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• 2006

The relationship between H. pylori clarithromycin resistance and genetic pattern distribution has been differently explained from different geographic areas. Therefore, we aimed to assess the clarithromycin resistance rate, to evaluate the bacterial genetic pattern, and to search for a possible association between clarithromycin resistance and cagA or vacA genes. This prospective study enrolled 62 consecutive H. pylori infected patients. The infection was established by histology and rapid urease test. Clarithromycin resistance, cagA and vacA status, including s/m subtypes, were assessed on paraffin-embedded antral biopsy specimens by TaqMan real time polymerase chain reaction (PCR). Primary clarithromycin resistance was detected in 24.1 % of cases. The prevalence of cagA was 69.3%, and a single vacA mosaicism was observed in 95.1 % cases. In detail, the s1m1 was observed in 23 (38.9%) patients, the s1m2 in 22 (37.2%), and the s2m2 in 14 (23.7%), whereas the s2m1 combination was never found. The prevalence of cagA and the vacA alleles distribution did not significantly differ between susceptible and resistant strains. Primary clarithromycin resistance is high in our area. The s1m1 and s1m2 are the most frequent vacA mosaicisms. There is no a relationship between clarithromycin resistance and bacterial genotypic pattern and/or cagA positivity.

• Korean Journal of Microbiology
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• v.21 no.2
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• pp.71-78
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• 1983

The number of aerobic free-living nitrogen fixation bacteria and factors in soil at different stands covered with Pinus rigida, Quercus acutissima and Zoysia japonica in Cheongju area were investigated from Feb. to Sept 1981. 1. The numbers of $N_2-fixation$ bacteria, according to the seasonal changes, increased gradually from winter to spring and summer. But the growth pattern revealed some differences in accordance with plant cover stands : the numbers increased abruptly in May at Pinus, May-June at Quercus and Apr. May at Zoysia stand. The pick of numbers represented in Aug. Sept, at Pinus, Jul-Aug. at Quercus and May-Jun. at Zoysia stand, respectively. 2. The interrelationship between the monthly changes of enviotnmental factors and numbers of $N_2-fixation$ bacteria at different stands, mainly depends upon the soil temperature than other soil factors (r=0.71-0.84). The numbers of $N_2-fixation$ bacteria may increase 5-7 times according to increase $10^{\circ}C$ of soil temperature, and optimal range was $20{\sim}30^{\circ}C$ for growth. Equation of the interrelation between soil temperature and numbers could be stated as follows : log y=ax+b. 3. In the case of high soil temperature, the bacterial numbers presented high level in drought periods. Therefore, the $N_2-fixation$ bacterial species in these soil seem to consist of resistant to desication. 4. The influence of soil organic matter for growth of $N_2-fixation$ bacteria indicated low conrelation. The reason may seen the content of organic matter in these soil existed abundantly above the quantities of limitation for growth. 5. In artifical gradients, the $N_2-fixation$ bacteria were predominated at $20{\sim}30^{\circ}C$ same as natural condition, pH7-8, and 20-30% of soil water contents. 6. The vertical distribution of bacteria marked decreasing trends from surface to lower layers, and the decreasing degree was shown well in Zoysia, Quercus and Pinus stand in order. But in the trees, the numbers increased at 30cm layer estimated the region of root than 20cm layer. 7. Both catalase megative and positive group of $N_2-fixation$ bacteria in soil increased according to the rise of the soil temperature. Catalase positive group was revealed as dominant group in winter, and catalase negative group revealed in summer. The change of dominant pattern was shown during Feb. to Apr.

• Korean Journal of Veterinary Service
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• v.35 no.4
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• pp.295-305
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• 2012

The aim of this study was to isolate microorganisms from half milk samples of dairy goats by California mastitis test (CMT) during the lactation period and to further investigate the susceptibility of isolated organisms to antimicrobial drugs. From a total of 235 half milk samples with CMT scores of 2 or above from 366 dairy goats distributed throughout Jeonnam province, microorganisms were isolated from 198 (83.5%) samples either singly (99.0%) or in combination (1.0%). The most prevalent microorganism was the coagulase-negative Staphylococcus spp., (44.4%, n=88) followed by Staphylococcus aureus (24.2%, n=48), Escherichia coli (11.1%, n=22) and Streptococcus spp. (7.6%, n=15). Isolated bacteria also included Bacillus spp. (2.5%, n=5), Pseudomonas spp. (2.5%, n=5), Micrococcus spp. (1.5%, n=3), Corynebacterium spp. (1.5%, n=3), Enterococcus facium (1.0%, n=2), Morganella morganii (0.5%, n=1) and Streptococcus agalactiae (0.5%, n=1). During the summer season, a high prevalence of all microorganisms were observed in which Staphylococcus spp. (30.8%), Escherichia coli (8.6%), and Streptococcus spp. (5.6%) were among the most prevalent bacteria isolated. Staphylococcus spp. was also shown to be high in the winter (21.7%). In most samples, the presence of bacterial pathogens in goat milk led to the increase in the total somatic cell count (SCC). Most of the half milk samples of dairy goats with bacterial contamination showed SCC of ${\geq}1{\times}10^6cells/ml$ (90.4%). Minor pathogens (11.4%) were more detected from milk samples with SCC of < $1{\times}10^6cells/ml$ than major pathogens (4.1%), while the major pathogens tended to be higher from samples with SCC of ${\geq}3{\times}10^6cells/ml$. Susceptibility of these bacteria to 12 antimicrobial agents was tested by the Kirby-Bauer disc diffusion method. Results indicated that more than 90% of bacteria isolated from CMT 2+ dairy goat half milk samples were susceptible to trimethoprim/sulfamethoxazole, amoxicillin/clavulanic, enrofloxacin and cephalothin while they were resistant to tetracycline (44.7%).

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.4
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• pp.420-429
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• 2000

Oral & maxillofacial infections are most commonly odontogenic in origin. Although such infections are usually self-limiting, they may occasionally spread deeply into fascial spaces or planes far from the initial site of involvement. If early diagnosis and appropriate therapy is delayed, complications such as mediastinal extension, retropharyngeal spread and airway obstruction could happen to the patients. For the study of the microbiology, we have retrospectively analysed the oral & maxillofacial infected patients in the Dept. of Oral & Maxillofacial Surgery. In-Ha University Hospital from 1997 September to 2000 April. The results were as follows 1. The male patients were more common than female, with male 61.9% and female 38.1%. 2. Dental originated infections were most common cause with the incidence of 62%. 3. Most common fascial space involved was buccal space 42cases(37.2%) followed by submandibular space 13cases(11.5%), infraorbital space 13cases(11.5%), masseteric space 11cases(9.7%), periapical abscess 11cases(9.7%). 4. The causative organisms isolated from the pus culture were Gram Positive Bacterial species, which were 46cases(31.9%) of Streptococcus viridans, 16cases(8.6%) of ${\alpha}$ and ${\beta}-hemolytic$ streptococcus, 4cases(3.1%) of Strep.-group D non enterococci, 7cases(5.1%) of Staphylococcus Coa. neg., 5cases(3.9%) of Staphylococcus aureus, 3cases(2.3%) of Enterococcus faecalis, 1case(0.8%) of Bacillus species, 1case(0.8%) of Peptostreptococcus, 1case(0.8%) of Clostridium and Gram negative bacterial species, which were 4cases(3.1%) of Acinetobacter baumannii, 2cases(1.6%) of Pseudomonas aeruginosa, 2cases(1.6%) of Burkholderia cepacia, 1case(0.8%) of Neisseria species, 1case(0.8%) of Klebsiella pneumoniae, 1case(0.8%) of Klebsiella oxytoca, 1case(0.8%) of Escherichia coli. 5. In drug sensitivity test, high resistant tendency was found in Penicillin system(Penicillin G 83.3%, Ampicillin 60%) and Aminoglycosides (Gentamycin 50%, Tobramycin 45.5%), but tertiary Cephalosporin system(Cefoperazone 9.1%, Ceftazidime 18.2%), and glycopeptides system (Teicoplanin 0%, Vancomycin 0%) showed lower resistancy.

• Korean journal of applied entomology
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• v.16 no.4 s.33
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• pp.229-234
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• 1977

The experiments were carried out to investigate the selection effects on the drug resistance to Agrepto in Xanthomonas oryzae, the causal bacteria of rice bacterial leaf blight. The results obtained were as follows. 1, The Agrepto was stable at the heat treatment of $105^{\circ}C$ for 20 minutes, when the drug was added in the media. 2. The local isolates of the bacteria, 75-6 and 75-9, showed the different resistante reaction, when they were selected by the Agrepto contained media which concentrations of 10r9/m1 and 100ug/ml. 3. The individuals shelving high degree of resistance, which can grow on the media contained 10,000ug/m1 of Agrepto, could selected by the concentrations as low as 10ug/ml and 100ug/m1, in one generation. 4. The highly resistant isolates which selected by 3-stepwise selections such as 100ug/ml, 3,000ug/ml and 10,000/ml plots, showed nearly normal growth at the media contained 100ug/ml of Agrepto 5. When the isolate 75-9 was selected at the 100ug/m1 of concentration, showed various degrees of resistance, indicating that the isolate may be composed of resistance groups that lower than 500ug/ml, between 500-1,000ug/ml and 1,000-3,000ug/ml, to the Agrept.

• Journal of Food Hygiene and Safety
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• v.26 no.3
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• pp.222-226
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• 2011

Salmonellosis is a major bacterial zoonosis that causes self-limited enteritis to fatal infection in animals and food-borne infection and typhoid fever in humans. Multidrug-resistant strains of Salmonella spp. has increased over the last several decades and recently causes more serious problems in public health. The present study was investigated bacteriocidal effects of sodium chlorate, sodium azide, sodium cyanide, and sodium salts mixture containing sodium chlorate, sodium azide, and sodium cyanide on infection with S. typhimurium in macrophage RAW 264.7 cells, and antibacterial effects of sodium salts mixture for murine salmonellosis. In infection assay of S. typhimurium in RAW 264.7 cells, bacterial survival rates within macrophage in all treated groups was significantly reduced comparing to that of the control group with the passage of incubation time. Administration of sodium salts mixture showed a therapeutic effect for S. typhimurium infected ICR mice. The mortality of mice treated with sodium salts mixture was 70% until 12 days, while that of control mice was 100% until 9 days after S. typhimurium infection. The results of this study strongly indicate that sodium salts mixture has a potency treatment for murine salmonellosis.

• Journal of fish pathology
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• v.20 no.3
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• pp.221-227
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• 2007

In this study, one hundred strains of bacterial flora were isolated from the intestine of cultured and wild black rockfish Sebastes inermis collected in Yeosu and examined for drug resistance to 9 antibiotics. From cultrued fish, the isolated bacteria were Photobacterium group (26 strains) and Acinetobacter group (18 strains) of Gram-negative, and unidentified marine sediment bacterium (6 strains) of Gram-positive. From wild fish, Photobacterium group (18 strains), Acinetobacter group (12 strains) and Shewanella group (5 strains) of Gram-negative and Bacillus group (8 strains), Staphylococcus group (4 strains), and unidentified marine sediment bacterium (3 strains) of Gram-positive. Intestine flora of wild black rockfish was more diverse than that of one cultured. The drugs tested were tetracyclines (oxytetracycline), aminoglycosides (gentamicin), macrorides (erythromycin) and quinolones (flumequine, oxolinic acid, norfloxacin, ofloxacin, enrofloxacin and ciprofloxacin). Sensitivity to all seven antibiotics except oxytetracycline and oxolinic acid was higher in bacteria from wild fish than from cultured ones, although wild isolates were more resistant than control strain Escherichia coli ATCC9637. This suggests that use of antibiotics in the fish farm might have some resistance in intestinal flora of wild fish.