• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.101-104
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• 1995

We isolated sixty lactic acid bacteria(LAB) from lactic fermented products. Among 60 isolates of LAB, 30 isolates were identified as Lactobacillus casei ssp.(5 strains), Lactobacillus acidophilus(2 strains), Lactobacillus delbrueckii ssp. bulgaricus(6 strains), Lactobacillus plantarum(4 strains), Streptococcus salivarius ssp. thermophilus(11 strains), and Streptococcus faecalis(2 strains). The acid tolerance and bile resistance of 30 LAB were determined. Because the acid tolerance was affected by the initial cell concentrations, the analysis of covariance could be used to remove the effect of initial cells on acid tolerance when testing for differences in acid tolerance among six species. Viability of LAB under acidic condition, pH 3 for 2 hours at $37^{\circ}C$, was significantly different among the species. L. casei and L. acidophilus strains showed great viability, but L. bulgaricus and S. thermophilus strains were very weak in acid tolerance.

• Mycobiology
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• v.44 no.4
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• pp.314-318
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• 2016

Breeding the button mushroom requires genetic information about its strains. This study was undertaken to genetically characterize four domestically bred button mushroom strains (Saea, Saejung, Saedo, Saeyeon cultivars) and to assess the possibility of using the intergenic spacer 1 (IGS1) region of rDNA as a genetically variable region in the genetic characterization. For the experiment, 34 strains of Agaricus bisporus, two strains of A. bitorquis, and one strain of A. silvaticus, from 17 countries were used. Nucleotide sequence analysis of IGS1 rDNA in these 37 Agaricus strains confirmed that genetic variations exist, not only among the four domestic strains, but also between the four domestic strains and foreign strains. Crossing two different haploid strains of A. bisporus seems to generate genetic variation in the IGS1 region in their off-spring haploid strains. Phylogenetic analysis based on the IGS1 sequence revealed all A. bisporus strains could be differentiated from A. silvaticus and A. bitorquis strains. Five genetic groups were resolved among A. bisporus strains. Saejung and Saeyeon cultivars formed a separate genetic group. Our results suggest that IGS1 could be complementarily applied in the polymorphism analysis of button mushroom.

• Journal of Microbiology and Biotechnology
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• v.31 no.5
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• pp.733-739
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• 2021

Acinetobacter strains are widely present in the environment. Some antimicrobial-resistant strains of this genus have been implicated in infections acquired in hospitals. Genetic similarities have been reported between Acinetobacter strains in nosocomial infections and those isolated from foods. However, the antimicrobial resistance of Acinetobacter strains in foods, such as meat, remains unclear. This study initially aimed to isolate Campylobacter strains; instead, strains of the genus Acinetobacter were isolated from meat products, and their antimicrobial resistance was investigated. In total, 58 Acinetobacter strains were isolated from 381 meat samples. Of these, 32 strains (38.6%) were from beef, 22 (26.5%) from pork, and 4 (4.8%) from duck meat. Antimicrobial susceptibility tests revealed that 12 strains were resistant to more than one antimicrobial agent, whereas two strains were multidrug-resistant; both strains were resistant to colistin. Cephalosporin antimicrobials showed high minimal inhibitory concentration against Acinetobacter strains. Resfinder analysis showed that one colistin-resistant strain carried mcr-4.3; this plasmid type was not confirmed, even when analyzed with PlasmidFinder. Analysis of the contig harboring mcr-4.3 using BLAST confirmed that this contig was related to mcr-4.3 of Acinetobacter baumannii. The increase in antimicrobial resistance in food production environments increases the resistance rate of Acinetobacter strains present in meat, inhibits the isolation of Campylobacter strains, and acts as a medium for the transmission of antimicrobial resistance in the environment. Therefore, further investigations are warranted to prevent the spread of antimicrobial resistance in food products.

• Korean Journal of Veterinary Research
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• v.26 no.1
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• pp.79-85
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• 1986

This paper deals with the isolation of Salmonella on 3 herds during the period from May 1984 to May 1985. Isolated Salmonella were examined for serotypes, adhesive fimbriae, antibiotic susceptibility and detection of R plasmid. The results were as follows; Of total 1505 cattle, 24 Salmonella were isolated from 18 cattle (1.2%) and their serotypes were S. enteritidis (9 strains), S. derby(4 strains), S. infantis (1 strain), $C_1$ group(8 strains), $C_2$ group(1 strain) and untypable(1 strain). Twelve strains of Salmonella were isolated from 227 cattle with diarrhea and their serotypes were S. enteritidis(4 strains), S. derby(3 strains), S. infantis(1 strain), $C_1$ group(3 strains) and untypable(1 strain). The isolation rate of Salmonella in cattle varied from 1.6 to 0.9% in 3 herds, it was higher in summer and autumn and lower with the age. Of total 24 strains, 23 were adhesive type 1 fimbriae. Antibiotic susceptibility test of Salmonella isolated was performed by the agar dilution method, using 9 antibiotics as follows: ampicillin(Am), chloramphenicol(Cm), gentamicin(Gm), kanamycin(Km), nalidixic acid(Na), rifampicin(Rf), streptomycin(Sm), sulfadimethoxine(Su) and tetracycline(Tc). All the strains tested were susceptible to Am, Cm, Gm, Km, Na, Rf and Tc. Of total 24 strains, 23(95.8%) were resistant to Su and 14(58.3%) to Sm. Of the 23 resistant Salmonella strains, all the strains were found to carry R plasmid. Among them, two strains which had the R plasmid conferring SmSu resistance was transferable at $25^{\circ}C$ only.

• The Journal of the Korean Society for Microbiology
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• v.18 no.1
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• pp.1-9
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• 1983

The author studied on the distribution of V. parahaemolyticus among sea water, sea mud, and various marine products in Jeju, Keoje, Namhae, Yockji, Busan, and Masan on the southern seas of Korea from winter in 1981 to summer in 1982. The author studies for the isolated strains to bacteriological identification Kanagawa phenomenon(hemolytic activity) on Modified Wagatuma blood agar plates and serotypes with anti V. parahaemolyticus. The results obtained were as follows:. 1. V. parahaemolyticus was isolated in 713 strains(28.3%) among 2519 total specimens of sea water, sea mud, and various marine products. 2. The isolation rates of V. parahaemolyticus in summer season were higher than in spring and winter season. Above results were 304 strains(32.6%) among 932 specimens in summer, 160 strains (28.1%) among 570 specimens in spring, 149 strains(14.6%) among 1017 specimens in winter, respectively. 3. The hemolysis on Modified Wagatuma agar added human erythrocytes was 66.0% of positive Kanagawa phenomenon, and was 34.0% of negative Kanagawa phenomenon, respectively. 4. The distributions of serotypes of V. parahaemolyticus isolated were from KI to K VIII of K pooling antisera. The results were 6 strains(6.6%) on K 1 of K I, 14 strains(l5.5%) on K 17 of K II, 26 strains(28.8%) on K 28 of K IV. 10 strains(11.1%) on K 32 of KV, 4 strains(4.4%) on K 39 of KV, 8 strains(8.8%) on K 42 of K VI, 2 strains(2.2%) on K 48 of K VII, 1 strain(1.1%) on K 50 of K II and 7 strains(7.7%) on K 55 of K VII, respectively. 5. V. parahaemolyticus was more frequently isolated from sea mud than sea water and various marine prdoucts in winter season. 6. There was no great difference as far as the distribution of V. parahaemolyticus concerned in Jeju, Keoje, Namhae, Yockji, Busan and Masan of the southern seas of Korea.

• The Korean Journal of Food And Nutrition
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• v.7 no.3
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• pp.203-212
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• 1994

The nangmyun is a Korean iced noodle made by putting buckwheat-noodles into cold broth. Seven samples of nangmyun-broths were collected from Korean restaurants in Bucheon during July 1994. The contamination levels of nangmyun-broths by coliform bacteria were determined, and then the 40 colonies of coliform bacteria, isolated randomly from 4 samples of nangmyun-broths, were identified at genus or species level with the additional test for psychrotrophic character The coliform counts in nangmyun-broths were 6.0x102-6.5$\times$104/ml(average 2.3$\times$104%). Among the 40 strains of isolates, 27 strains(67.5%) were identified as the genus Klebsiella, 9 strains(22.5%) as the genus Enterobacter, 2 strains(5.0%) as the genus Citrobacter and 2 strains (5.0%) as the genus Escherichia. Among 27 strains of Klebsiella, 11 strains (40.8%) were identified as K planticola, 4 strains(14.8%) as K. pneumoniae, 2 strains(7.4%) as K. ozaenae and 2 strains(7.4%) as K. terrigena, but 8 strains(29.6%) of a typic\ulcorner1 Klebgiella could not be Identified at species level. All the 40 strains of coliform bacteria were psychrotrophs showing slow growth at 1$0^{\circ}C$, and 18 strains(45%) grew at 5$^{\circ}C$. It was thought to be a good basic data In describing the reason for too high coliform counts in nangmyun-broths that all coliform bacteria tested In this study were psychrotrophs.

• Journal of Microbiology and Biotechnology
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• v.27 no.7
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• pp.1223-1232
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• 2017

Cordyceps militaris, a member of Ascomycota, a mushroom referred to as caterpillar Dong-chung-ha-cho, is commercially valuable because of its high content of bioactive substances, including cordycepin, and its potential for artificial cultivation. Cordycepin (3'-deoxyadenosine) is highly associated with the pharmacological effects of C. militaris. C. militaris is heterothallic in that two mating-type loci, idiomorph MAT1-1 and MAT1-2, exist discretely in two different spores. In this study, nine C. militaris strains were mated with each other to prepare newly bred strains that produced a larger amount of cordycepin than the parent strains. Nine strains of C. militaris were identified by comparing the internal transcribed spacer sequence, and a total of 12 single spores were isolated from the nine strains of C. militaris. After the MAT idiomorph was confirmed by PCR, 36 mating combinations were performed with six single spores with MAT1-1 and the others with MAT1-2. Eight mating combinations were successfully mated, producing stroma with perithecia. Cordycepin content analysis of all strains by high-performance liquid chromatography revealed that the KASP4-bred strain produced the maximum cordycepin among all strains, regardless of the medium and stroma parts. Finally, universal rice primer-PCR was performed to demonstrate that the bred strains were genetically different from the parental strains and new C. militaris strains. These results may be related to the recombination of genes during mating. The newly produced strains can be used to meet the industrial demand for cordycepin. In addition, breeding through mating suggests the possibility of producing numerous cordycepin-producing C. militaris strains.

• Korean Journal of Poultry Science
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• v.7 no.1
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• pp.53-64
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• 1980

A total of 1503 specimens were submitted to the Poultry Disease Diagnostic Service Laboratory during the year 1966 and 1978. The most frequently diagnosed diseases in order of prevalence were avian mycoplasmosis, staphylococcosis, colibacillosis, salmonellosis and pullorum disease, the percentages of the conditions being 24.6%, 20.0%, 18.0%, 12.6% and 6.4%, respectively, The drug resistance of pathogenic mirnoorganisms isolated during the year 1978 from chicken with colicabacillosis, staphylococcosis or salmonellosis were investigated by the use of disc diffusion technique, the results being as follow. 1) Drug resistance of 63 strains of Escherichia coli More than 95% of the strains tested were sensitive to colistin and gentamicin. The percentages of strains sensitive to kanamycin, chloramphenicol, ampicillin and nitrofurantoin were 66.7%, 60.3%, 60.3% and 47.6%, respectively. Majority of the strains were highly resistant to streptomycin and tetracyline. All the strains were resisistant to bacitracin lincomycin, oleandomycin, penicillin and erythromycin. All the strains tested were resistant to more than two among 10 drugs in common use such as penicillin, erythromycin, streptomycin, tetracycline, neomycin, chloramphenicol, kanamycin, ampicillin and gentamicin, and 27 different resistance patterns were noted. The most frequent multiple resistance pattern was PC, EM, SM and TC (11.1%). 2) Drug resistance of 48 strains of Salmonella More than 95% of the strains tested were sensitive to colistin, gentamicin ana ampicillin. The percentages of st rains sensitive to kanamycin, tetracycline, neomycin and nitrofurantoin were 81,3%, 79%, 72.9%, and 68.0% respectively. None of them was sensitive to streptomycin, oleandomycin, erythromycin, lincomycin and bacitracin. All the strains were resistant to more than one among 7 drugs in common use such as streptomycin, erythromycin, neomycin, tetracycline, kanamycin, ampicillin and gentamicin. The most frequent resistance pattern was SM and EM(66.7%). 3) Drug resistance of 54 strains of Staphylococci All the strains tested were sensitive to gentmaicin, kanamycin and cephalothin. Majority of them were highly sensitive to bacitracin, methicillin, nitrofurantoin and chloramphenicol. The Percentages of strains sensitive to streptomycin, ampicillin, lincomycin and tetracycline were 66.7%, 55.6%, 44.4% and 27.8%, respectively. Among them, 51 strains were resistant to more than one among 11 drugs in common use such as tetracycline, lincomycin, ampicillin, penicillin, streptomycin, erythromycin, neomycin, oleandomycin, chloramphenicol, methicillin and bacitracin, and thirty one different resistance patterns were noted.

• The Journal of the Korean Society for Microbiology
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• v.5 no.1
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• pp.1-8
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• 1970

This report is to observe the rate of multiple resistance to various antibiotics among staphylococcus aureus and E. coli which were isolated with high frequency at our department during 1969. 1. One hundred fifty two strains(20.6%) resistant to four antibiotics multiple resistant was the highest incidence among 739 strains of Staphylococcus aureus. 2. Regarding the multiple antibiotic resistant of Staphylococcus aureus, 75strains(10.1%) to SA. PC. TC the three antibiotics resistant, have been observed, with the highest incidence, and next to this, 69 strains(9.3%) to SA. PC. SM. TC the four autibiotics resistant, and 68 strains(9.2%) to SA. PC. SM. CM. TC. SM. the six antibiotics resistant, have been observed in descending order. 3. The case of one hundred twenty seven strains(28.0%) of the six antibiotic multiple resistant among 454 strains of Escherchia coli was the highest incidence. 4. Concerning the multiple antibiotic resistant of Escherichia coli, 70 strains(l5.4%) to SA. SM. CM. TC. EM. FD. the six antibiotics resistant, have been observed, with the highest incidence, and next to this, 59 strains(l3.0%) to SA. SM. CM. TC. EM. FD. AC the seven antibiotics resistant, and 42 strains(9.3%) to SA. SM. CM. TC. EM. FD. KM. AC the eight antibiotics resistant have been observed in descending order.

• Journal of Food Hygiene and Safety
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• v.9 no.3
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• pp.141-149
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• 1994

To investigate the distribution of Vibrio parahaemopyticus in the southern 4 coastal areas, Vibrio parahaemolyticus was isolated from seawater, shellfish and sediment from May to October in 1991, and antimicrobial effect of grapefruit seed extract (GFSE) on the growth of isolated strains were examined. In the 120 sample from 4 coastal areas, 16 strains of Vibrio parahaemolyticus were isolated and identified. The distribution serotype of isolated strains was 10 types of monovalent k-antiserum. Especially k-5 and k-28 were highly distribyted with 3 and 4 strains. 31.3% of isolated strains showed positive on Kanagawa phenomenon test. All isolated Vibrio parahaemolyticus were sensitive to chloramphenicol and gentamycin, 5 and 6 strains were resistant to streptomycin and colistin, respectively. Isolated strains were compared with geographical, month and sample. The distribution of 16 isolated Vibrio parahamolyticus was high at Hadong with 50%(8 strains), on July with 43.8%(7 strains) and from seawater with 37.5%(6 strains) respectively. Minimal inhibitory level of GFSE to Vibrio parahaemolyticus was 50 ppm. With 100 ppm treatment of GFSE, the destroy of cell membrane function, outflow of cell ingredients and ghost morphology of cell were investigated.