• Journal of Food Hygiene and Safety
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• v.15 no.3
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• pp.241-247
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• 2000

The incidence of verotoxin-producing Escherichia coli(VTEC) was surveyed in domestic foods including hamburger, raw meats and vegetables from 1997 to 1999. The molecular biological characteristics of the isolates were analyzed. Three VTEC strain were isolated from 1,700 samples. Serotypes of those isolates were 0157 : H7, 026 H4, and 056 : Hl2, respectively. Serotype O26 : H4 produced VT I and VT II, and 055 Hl2 isolate produced VT I, however the 60 MDa plasmid DNA and eae gene were not found from both strains. One 0157 : H7 isolate produced VT II and harbour 60 MDa plasmid DNA, however eae gene was not found in the strain. Although they produced VT, it seemed that the virulence of two strains were relatively weak because of the lack of the eae gene. In addition, the serotype O157 : H7 isolate resistant to ampicillin and streptomycin, while isolates of serotype O26 : H4 and O55 : Hl2 were multi-resistant to antibiotics including ampicillin, carbenicillin , cephalothin, trimethoprim/sulfamethoxazole and tetracycline. Supernatants of cultures of all three isolates were showed cytotoxic effect to vero and HeLa cell

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.104-110
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• 2004

To determine evolution and genotype of new chromosomal AmpC $\beta$-lactamases among clinical isolates of Enterobacter species, we performed antibiotic susceptibility testing, pI determination, sequencing, and phy-logenetic analysis using developed expression/secretion vector. Six isolates have shown to produce AmpC $\beta$-lactamases. Six genes of AmpC $\beta$-lactamases that are responsible for the resistance to cephamycins (cefoxitin and cefotetan), amoxicillin, cephalothin, and amoxicillin-clavulanic acid were cloned and characterized in pMSG12119. Insert fragment containing the ampC genes was sequenced and found to have an open reading frame coding for 381-amino-acid $\beta$-lactamase. The nucleotide sequence of four ampC genes ($bla_EcloK992004.l$, $bla_EcloK995120.1$, $bla_EcloK99230$, and $bla_EareK9911729$) shared considerable homology with that of chromosomal ampC gene ($bla_EcloMHN1$) of E. cloacae MHN1 (more than 99.6% identity). The sequences of two ampC genes ($bla_EcloK9973$ and $bla_EcloK9914325$) showed close similarity to the chromosomal ampC gene ($bla_EcloQ908R$) of E. clo-acae 908R (99.7% identity). The results from phylogenetic analysis suggested that six ampC genes could be originated from $bla_EcloMHN1$ / or $bla_EcloQ908R$ / MIC patterns and exact pI values of six transformants indicated that the developed expression/secretion vector (pMSG1219) was suitable for the characterization of foreign genes in E. coli strain.

• Journal of Food Hygiene and Safety
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• v.16 no.1
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• pp.27-32
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• 2001

Antibiotic resistance of thirty strains of Shigella sonnei isolatedfrom patient of Shigellosis outbreke at Young Cheon area in 1998 was tested. Twenty-seven strains were resistant to Tr(Trimethoprim-Sulfamethoxazol) and Shigella sonnei SG-48 was resistant to Tr(Trimethopirm-Sulfamethoxazol), Ap(Ampicillin), Cp(Cephalothin) and Pi(Piperacillin). Shigella sonnei SG-49, SG-66, and SG-73 were senstive to all tested antibiotics. Physiological charactristics of isolated Shigella sonnei SG-48, SG-49, SG-57, and SG-73 such as effect of pH, NaCl concentration and temperature on the growth, survival in adverse condition and heat resistance were investigated Growth of the strains were inhibited at pH 4 and pH 9. All strains were grown in Tryptic soy broth containing 6% of NaCl but inhibited in TSB containing 9% of NaCl except Shigella sonnei SG-73 after incubation for 18hrs at 37$^{\circ}C$. Selected strains grew during storage at 10 but did not grow at 4. The strains were survived in 1% pepton solution for 15 days at 37$^{\circ}C$. Viable cell of selected strains were decreased 45 log cycle after heat treatment for 30 mins at 6$0^{\circ}C$ but did not detect by heat treatment for 5 mins at 7$0^{\circ}C$.

• Journal of Food Hygiene and Safety
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• v.30 no.1
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• pp.51-58
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• 2015

Thirty one of Staphylococcus aureus isolated from perilla leaf cultivation areas in Miryang were investigated on the characteristics, such as enterotoxin genes and antibiotic susceptibility. Five toxin genes (sea, seb, sec, sed, and see) were examined by PCR method. Disc diffusion method was used to examine the antibiotic susceptibility of S. aureus by using 18 types of antibiotic discs with different concentrations. Among enterotoxin-encoding genes, sea and sed genes were co-detected from 4 isolates (12.9%), sed gene was founded in 9 isolates (29.0%), and see gene was founded in 1 isolate (3.2%). However seb and sec and tsst were not detected in any isolates. As a result of antibiotic susceptibility test, 7 isolates (22.6%) were resistant to 12 antibiotics (penicillin, ampicillin, oxacillin, amoxicillin-clavulanic acid, cefazolin, cephalothin, imipenem, gentamicin, tetracycline, ofloxacin, norfloxacin, and erythromycin). 2 isolates (6.5%) were resistant to 5 antibiotics (penicillin, ampicillin, amoxicillin-clavulanic acid, gentamycin, and telithromycin). MRSA (Methicilline Resistant Staphylococcus aureus) was founded in packing vinyl, hands, and perilla leaves.

• Food Science and Preservation
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• v.5 no.3
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• pp.292-298
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• 1998

The isolates from putrefying soybean curd were identified as Acinetobacter calcoaceticus, Bacillus cereus, Bacillus sp., Cardiobacterium sp., Escherichia coli, Klebsiella pneumoniae, Pantoea sp., Salmonella typhimurium, Staphylococcus aureus, Xenorhabdus luminescens, Yersinia sp.. The existence percentages of the bacteria from putrefying soybean curd at room temperature storage were Bacillus cereus J55 23.57%, Xenorhabdus luminescens J48 22.73%, Acinetobacter calcoaceticus J61 22.26%, Klebsiella pneumoniae J62 21.25%, Salmonella typhimurium J51 2.87%, Pantoea sp. J57 2.65%, Bacillus sp. J58 1.43%, Cardiobacterium sp. J54 1.26%, Escherichia coli J53 1.20%, Staphvlococcus aureus J6O 0.93%, Yersinia sp. J50 0.05%, respectively. Four out of eleven bacteria as B. cereu J55, X. luminescens J48, Ac. calcoaceticus J61, Kl. pneumoniae J62 putrefied soybean curd and those bacteria produce amylase or proteinase as a extracellular enzyme. But S. typhimurium J51, Pantoea sp. J57, Bacillus sp. J58, Cardiobacterium sp. J54, E. coli 153, St. aureus J60, Yersinia sp. J50 were not putrefied soybean curd. The isolates detected to resistant on various antimicrobial agents. The majority were resistant to aminoside antiboitics as amicacin, gentamicin, tobramycin and were susceptible to ${\beta}$-lactamine antibiotics as penicillin G, oxacillin, cephalothin cefazolin, cefamandole.

• Korean Journal of Agricultural Science
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• v.42 no.1
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• pp.29-35
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• 2015

This study was performed to analyze the distribution and antimicrobial resistance of pathogenic microorganisms isolated from the carcass and environments of chicken processing plant located in Gyeonggi province from October to November in 2010. Chicken slaughterhouse was visited 3 times and totally 40 samples were collected from chicken carcass before and after washing (n=14), chicken cuts (n=7), cooling water (n=8), brine (n=2), cutting knives (n=7) and working plate (n=2). Whole-chicken rinsing technique (for chicken carcasses) and swab technique (for working plate and knives) were used to analyze the distribution of pathogenic microorganisms. In addition, brine and chilling water from storage tanks were gathered using sterilized tubes and used as samples. The matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) for whole cell fingerprinting in combination with a dedicated bioinformatic software tool was used to identify the isolated microorganisms. The pathogenic microorganisms, such as Bacillus cereus (n=8) and Staphylococcus aureus (n=9), were isolated form the chicken processing process (chicken carcasses of before and after chilling, chicken cuts, and working plate). The antimicrobial susceptibility of those isolated microorganisms was analyzed using 21 antimicrobial agents. In the case of B. cereus, it showed 100% of resistance to subclasses of penicillins and peptides, and it also resistant to cephalothin, a member of critically important antimicrobials (CIA), however there was no resistance (100% susceptible) to vancomycin and chloramphenicol. S. aureus showed 100% resistance to subclasses of peptides and some of penicillins (penicillin and oxacillin), however, it showed 100% susceptibility to cephalosporins (cefazolin and cephalothin). All of the tested pathogens showed multi drug resistance (MDR) more than 4 subclasses and one of B. cereus and S. aureus showed resistance to 9 subclasses. After the ban on using the antimicrobials in animal feed in July 2011, there would be some change in microbial distribution and antimicrobial resistance, and it still has a need to be analyzed.

• Journal of Life Science
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• v.20 no.10
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• pp.1549-1555
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• 2010

Streptococcus suis is a worldwide pathogen of a variety of porcine infection and has also been described as a pathogen for humans. We studied biochemical characteristics, antimicrobial susceptibility, and identification of polymerase chain reaction (PCR) of S. suis isolated from diseased pigs in Gyeongbuk province from 2004 to 2009. Sixty-one isolates were identified as S. suis by biochemical characteristics and PCR from 40 farms. The biochemical characteristics of S. suis isolates were production of VP-negative, hippurate, esculin, and arginine decarboxylase-positive, and fermentation of carbohydrate was variable lactose, trehalose, inulin, and raffinose, which was typeable 11 phenotype. In an antimicrobial susceptibility test, the majority of isolates were highly susceptible to amoxicillin/clavulanic acid, ampicillin, cephalothin, cefoperazone and florfenicol, while being highly resistant to streptomycin, kanamycin, amikacin, neomycin, erythromycin, clindamycin, and tetracycline. The isolates were divided into 11 phenotypes of biochemistry. By using PCR, the 16S-rRNA gene DNA fragment was detected at 304 bp from all of isolates. These results may provide the basic information needed to establish strategies for the prevention of S. suis infection in pigs.

• Microbiology and Biotechnology Letters
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• v.11 no.3
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• pp.233-239
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• 1983

Bacillus thuringiensis was mutagenized with UV light irradiation and nitrosoguanidine. Twenty-four tem perature-sensitive ts mutants were isolated at 42$^{\circ}C$ and classified into two groups by growth on nutrient agar at 42$^{\circ}C$. First is the lethal group, which did not grow at the nonpermissive temperature, the second is the reduced group whose growth was restricted from one-half to one-fourth, Thirteen ts mutants belong to the lethal group and eleven ts mutants belong to the reduced group. Auxotrophic mutant, A-N28 required five amino acids as growth factors, A-N65 also five amino acids, A-N92 seven, A-N115 four and A-N156 three. Bacillus thuringiensis wild type is resistant to penicillin, ampicillin, and cephalothin. The ts-Ul7l, A-N92 and A-Nl15 are sensitive to the three antibiotics. The ts -U601, -U603, -U604 and -Ul71 did not grow at the permissive temperature after temperature-shifting from 42$^{\circ}C$. Four auxotrophic mutants (A-N38, A-N65, A-N92 and A-Nl15) did not form spores in their cells.

• Korean Journal of Microbiology
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• v.48 no.1
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• pp.22-28
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• 2012

Vibrio parahaemolyticus is one of the major agents responsible for food poisoning during summer in Korea, which is transmitted via seawater or seafoods. Recently, distribution of the bacteria in the marine environment has been increased due to global warming. Great concern also has been raised regarding public hygiene as well as marine culture by the emergence of pathogens with antibiotic resistance. Therefore, distribution of V. parahaemolyticus and antibiotic resistance of the isolates were monitored in 7 coastal areas of Kyonggi Province and Incheon by sampling seawater, fishes and clams monthly. V. parahaemolyticus was detected from 47.7% of 966 samples (seawater 61.9%, seafoods 41.8%) analyzed using $CHROMagar^{TM}$ and TCBS agar plates as well as multiplex PCR. Among 13 antibiotics tested, resistance to vancomycin and ampicillin was observed in 97.3% and 87.3% of the isolates, respectively, and the ratios of them resistant to cephalothin (48.8%) and rifampin (46.1%) were also high. The isolates were most highly sensitive to chloramphenicol (91.7%) and trimethoprim-sulfamethoxazole (91.8%). The ratio of sensitivity for other antibiotics was also high in the descending order of gentamycin (82.3%), tobramycin (74.8%), nalidixic acid (71.6%), tetracyclin (69.4%), cefotaxime (63.0%). About 69% of the isolates showed multiple drug resistance toward 3 antibiotics including vancomycin and ampicillin. Two of them exhibited resistance for 11 antibiotics used in this study. Plasmid profile analysis of the isolates with antibiotic resistance revealed that 55.1% of them retained plasmids of 24 different types. However, no clear inter-relationship between the resistance and the plasmid profile has been observed.

• Korean Journal of Veterinary Research
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• v.40 no.1
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• pp.173-186
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• 2000

This experiment was carried out to investigate the tendency of incident diseases in pre- and post- weaning piglets which ages were 1 to 7 weeks old by laboratory diagnosis and in order to minimize death in preweaning piglets and of stunted growth in postweaning piglets. The result of this experiment used as the basic data for the preventive programs in pre- and post- weaning piglets and were as follows: 23 different diseases diagnosed in 331 cases were studied in relation to age, season, and etiology. The most prevelent diseases of pre- and post- weaning piglet were Colibacillosis(79 case, 23.9%) and the major diseases were Salmonellosis(44 cases, 13.3%), Anemia(37 cases, 11.2%). Unknown viral disease(20 case, 6.1%), Rota viral infection(19 case, 5.8%), Porcine reproductive & respiratory syndrome(PRRS; 15 case 4.5%), Transmissible gastroenteritis(TGE; 12 case, 3.6%). The gastrointestinal disease, such as Colibacillosis, Salmonellosis, Swine dysentery, Clostridial infection, Rotaviral infection, TGE, Porcine epidemic diarrhea(PED) and Ballantidiosis occured pro- dominently in the period of pre- and post- weaning, which were 178 cases(53.8%) and not related to occurrence according to age and season. The respiratory diseases were Atrophic rhinitis(AR), Swine enzootic pneumonia, Pneumonic pasteurellosis, Pleuropneumonia, Branchopneumonia, PRRS and which were 48 cases(14.5%) and higher prevalent in spring and summer. The viral diseases was 73 cases(22.1%) that occurred in the period of 5 weeks piglet and prevalent mainly in spring. The bacterial diseases were 188 cases(56.8%) that were not related to occurrence according to age and season. Salmonellosis was prevalent in 3 to 5 weeks piglet and mainly occurred in summer. Viral septicemia and rotaviral infection occurred after 5 weeks piglets intensively and 3 to 5 weeks, respectively. And the both occurred without relation with season. PRRS occurred after 4 weeks piglet and prevalent in summer. TGE occurred 1 to 7 days old piglets and prevalent in spring and winter. Hematologic values of anemia was decrease in number of Red Blood Cell, concentration of Hemoglobin and Hematocrit. Amikacin, cephalothin, colistin, norfloxacin were effective to E coli, and amikacin, cephalothin, nortloxacin, neomycin were effective to Salmonellra spp. but clindamycin, erythromycin, penicillin, sulfonamides were resistant to E coli and Salmonella spp.