• Journal of Microbiology and Biotechnology
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• v.34 no.5
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• pp.1101-1108
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• 2024

Earlier studies have validated the isolation of extended-spectrum beta-lactamase-producing Salmonella (ESBL-Sal) strains from food. While poultry is recognized as a reservoir for Salmonella contamination, pertinent data regarding ESBL-Sal remains limited. Consequently, the Ministry of Food and Drug Safety has isolated Salmonella spp. from retail meat and evaluated their antibiotic susceptibility and genetic characteristics via whole-genome sequencing. To further elucidate these aspects, this study investigates the prevalence, antibiotic resistance profiles, genomic characteristics, and homology of ESBL-Sal spp. obtained from livestock-derived products in South Korean retail outlets. A total of 653 Salmonella spp. were isolated from 1,876 meat samples, including 509 beef, 503 pork, 555 chicken, and 309 duck samples. The prevalence rates of Salmonella were 0.0%, 1.4%, 17.5%, and 28.2% in the beef, pork, chicken, and duck samples, respectively. ESBL-Sal was exclusively identified in poultry meat, with a prevalence of 1.4% in the chicken samples (8/555) and 0.3% in the duck samples (1/309). All ESBL-Sal strains carried the bla_CTX-M-1 gene and exhibited resistance to ampicillin, ceftiofur, ceftazidime, nalidixic acid, and tetracycline. Eight ESBL-Sal isolates were identified as S. Enteritidis with sequence type (ST) 11. The major plasmid replicons of the Enteritidis-ST11 strains were IncFIB(S) and IncFII(S), carrying antimicrobial resistance genes (β-lactam, tetracycline, and aminoglycoside) and 166 virulence factor genes. The results of this study provide valuable insights for the surveillance and monitoring of ESBL-Sal in South Korean food chain.

• Pediatric Infection and Vaccine
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• v.14 no.1
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• pp.83-90
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• 2007

Purpose : Staphylococcal scalded skin syndrome (4S) is a well known disease defined by clinical, microbiological and histological criteria caused by Staphylococcus aureus. This disease is uncommon but has been increasingly recognized. We investigated the clinical features of staphylococcal scalded skin syndrome. Methods : We reviewed retrospectively medical records of 53 patients diagnosis of staphylococcal scalded skin syndrome who were admitted to Changwon Fatima hospital from February 2002 to December 2005. These patients were divided into 3 clinical types; generalized type, intermediate type, abortive type. Age, sex ratio, clinical manifestations, laboratory findings, response to therapy and prognosis were investigated. Result : 1)The mean age of patients was 2.8 years, ranging from 20 days to 7 years. Male-to-female ratio was 1.9:1. 2) By clinical types, 6 patients were in the generalized type (11%), 29 patients in the intermediate type (55%), 18 patients in the abortive type (34%). The coexisting diseases were variable, including conjunctivitis (25 cases), atopic dermatitis (11 cases), otitis media (1 case). On laboratory findings, most of patients didn't have leukocytosis or increased C-reactive protein. 4) A total of fifteen Methicillin Resistant Staphylococcal Aureus (MRSA) strains were isolated from September 2003 through December 2005. Fourteen strains were positive for exfoliative toxin B gene by PCR and negative for enterotoxin, toxic shock syndrome toxin and Panton-Valentine leukocidin genes. 5) The mean duration of admission was 7.3 days. Patients were treated with vancomycin or amoxacillin/clavulanate or ampicillin/sulbactam or cefuroxime without significant sequelaes. Conclusion : Recently, Staphylococcal scalded skin syndrome caused by exfoliative toxin B produced by MRSA in the Changwon area has been increasing.

• The Journal of the Korean Society for Microbiology
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• v.15 no.1
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• pp.55-62
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• 1980

Eleven strains of lactobacilli were isolated from fermented milk of 9 companies. They were classified 3 strains as L. bulgaricus, 2 strains as L. plantarum, 2 strains as L. cellobiosus, 1 strain as L. lactis, 1 strain as L. acidophilus, 1 strain as L. casei subsp. casei and 1 strain as L. casei subsp. tolerans. And these strains were examined for drug resistance, transferability and transfer frequency of R plasmid. Most of isolates were sensitive to tetracycline(TC), penicillin(PC), and erythromycin(EM), but some strains were resistant to streptomycin(SM), chloramphenicol(CP), ampicillin(AP), kanamycin(KM), and nalidixic acid(NA). All of isolates were resistant to two or more drugs and 6 different drug resistant patterns were found. The most frequently encountered patterns were NA AP CP SM KM(5 strains) followed by NA AP CP KM(2 strains), NA AP CP SM(1 strain), NA AP CP(1 strain), NA CP(1 strain) and NA AP(1 strain). Tranfer experiment of drug resistance showed that of all 11 resistant strains, 9 strains transferred R plasmid determining AP(6 strains) or AP SM(3 strains) to a recipient, E. coli ML 1410 strain with $2.8{\times}10^{-5}-1.5{\times}10^{-1}%$ of transfer frequency. These results indicate that lactobacilli conjugally transfer their resistance to E. coli.

• Journal of fish pathology
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• v.10 no.2
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• pp.125-135
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• 1997

The possibility of identification of families of antibacterial agent residues in fish tissue was studied by disk assay using three test organisms, Bacillus subtilis BGA, Micrococcus luteus ATCC 9341, and Bacillus cereus var. mycoides ATCC 11778. In the present method, a simple clean-up procedure was performed to obtain the aqueous solution from homogenized flounder muscle sample(10g) in Mcilvaine buffer. Then, aqueous solution was fractionated into A and B to be used in disk assay by choloroform and Sep-Pak $C_{18}$ cartridge column after being defatted in hexane. The chloroform layer of fraction A was used for the analysis of macrolide antibiotics(ML), sulfa drugs(SA), chloramphenicol(CP), and quinolone antibiotics(QN). Adsorbed materials to Sep-Pak $C_{18}$ of fraction B were also employed for the analysis of penicillins(PC), tetracyclines(TC), and nitrofuran derivatives(NF) Minimun-detectable concentrations by the present method were, $0.1{\mu}g$/g for oxytetracycline, tetracycline, doxycycline, spiramycin and ciprofloxacin, $0.025{\mu}g$/g for erythromycin and ampicillin, $1.0{\mu}g$/g for sodium nifurstyrenate and florfenical, $0.25{\mu}g$/g for sulfamonomethoxie and sulfadimethoxine, $2.5{\mu}g$/g for oxolinic acid and flumequine, and $15{\mu}g$/g for piromidic acid, respectively. Three test organisms showed different sensitivity patterns for each family of antibacterial agent. Sensitivity patterns were B. cereus > B. subtilis > M. luteus for TC and NF, M. luteus > B, subtilis > B. cereus for ML and PC, B. cereus = B. subtilis > M. luteus for CP and QN, and B. subtilis > B. cereus＝M. luteus for SA. The present method utilizing these characteristics could be useful as a routine screening test for the determination of family of antibacterial agent residues in fish tissue.

• Pediatric Infection and Vaccine
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• v.13 no.1
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• pp.71-77
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• 2006

Purpose : Shigellosis is still an important cause of acute food-borne diarrheal diseases throughout the world. We investigated the transmission routes and clinical course through the outbreak of shigellosis in Mapo-Gu, Seoul. Methods : From October 7th to November 19th in 2005, Mapo-Gu public health center had referred 32 patients with confirmed or suspected shigellosis to the National Medical Center. We had investigated source of infection, epidemiology, laboratory findings, and clinical course of the cases occurred during this outbreak. Results : Among 32 patients, 24 patients had been confirmed with shigellosis, 8 patients had been diagnosed with suspected shigellosis. They ranged in age from 5 months to 12 years old and their mean age was 6.5 years. The clinical manifestations were as follows; diarrhea, fever, abdominal pain and asymptomatic condition. Symptoms had sustained for 3.7 days on the average. S. sonnei were cultured by rectal swab and founded to be resistant to ampicillin and TMP/SMX except to 3rd generation cephalosporin. After treatment with antibiotics such as cefixime and ceftriaxone or imipenem and conservative treatment with electrolyte and fluid replacement for 5~7 days, Stool cultures of the rectal swab grew no Shigella in these cases except 3 cases. Conclusion : An outbreak of shigellosis had occurred in a preschool and elementary school children. From the same results of antimicrobial susceptibility and pulsed-field gel electrophoresis patterns in this study, we suggest that the outbreak of shigellosis in this report had been originated from a single strain. According to all negative results about suspected food and water cultures, we couldn't find out source of infection. Through materials offerred by Mapo-Gu Public Health Center, we presumed the trasmission routes probably were person-to-person.

• Journal of Preventive Medicine and Public Health
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• v.21 no.1 s.23
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• pp.183-194
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• 1988

This study was carried out to investigate for resistance of V. parahaemolyticus that isolated from patients of food poisoning and fish and shellfish, captured in east coast of Kyungpook province of Korea from 1985 to 1986. VP ATCC 17802 and NAG V. ATCC 6538 were used as control. In fish, shellfish and seaweed, the more temperature increased, the shorter survival time was. In case of sea-water, the more temperature rose up, the longer survival time was, particularly in $37^{\circ}C$ and $25^{\circ}C$, the strains had survived after 6 months. And in tapwater, it was sterilized in 150 mins. and survived for 11.5 days on maximum in ground water. In kimchi, at room temperature, germicidal time was shorter more than 6 times compared with that which had been kept in refrigerator. It survived for 57.1 days in milk, 49.2 mins. in yougurt. Strains had been surviving in frozen condition at $-70^{\circ}C$ even after 6 months, present study time. In resistance test in water bath at several degrees of temperature, all the strains were sterilized in 20 mins. with $60^{\circ}C$. In resistance test to driness, number of surviving strains dropped rapidly in 10-11%) water contents. In UV $2538{\AA}$, strains were sterilized in 20 mins. In resistance test to alcohol, strains had survived for 0.1-4 mins. in fermentative wine of below than 25% and distilled wine of over than 25% in alcohol concentration. The bactericidal concentration of disinfectant was 1% in phenol and 3% in cresol. In 0.1M acetic acid and 0.1M lactic acid, number of surviving colonies decreased rapidly but not in citric acid. The more NaCl concentration rose up, the lower decreasing rate of number of surviving colonies was. The strains had showed sensitive response to vancomycin, chloramphenicol, gentamicin, and resisted to carbenicillin, ampicillin and kanamycin. When one day culture strain was cultured till 25th day, resistant strains to tetracycline and cephalothin were changed to sensitive.

• Biomedical Science Letters
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• v.1 no.1
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• pp.55-72
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• 1995

Forty gentamicin-resistant isolates of Enterococcus faecalis were selected from various clinical materials, determined their antimicrobial susceptibility, and studied there R-plasmid characteristics and polypeptide patterns. All of the isolates were susceptible to vancomycin. The MICs($\mu$/ml) of antimicrobial agents to the isolates were as follows; the MIC of gentamicin was 128 and $\geq$2040, ampicillin 1 and 1, chlorarmphenicol 2 and 8, erythromycin 32 and 256, and vancomycin 1 and 2. E. faecalis HL-1 strain had 8 plasmid DNA elements, HL-2 and HL-3 strains had 6, HL-4 had 7, HL-5 had 4, and HL-6 had 5. The 51.7 Kb of gentamicin resistance plasmid DNA was conjugally transferred from two strains of E. faecalis HL-1 and HL-6 to S. aureus SK 982. The plasmid transfer frequency between S. aureus SK 982 and E. faecalis HL-1 or E. faecalis HL-6 was 6.3$\times10^{-4} and 3.7$\times10^{-5}$, respectively. Plasmid curing ratio after the treatment of ethidium bromide(10$\mu$/ml) to E. faecalis tarnsconjugants R-1 and R-6 were about 51% and 67%, respectively. The tetracycline gene was located in 2.15 Kb plasmid of E. faecalis HL-1, but it was not found in the E. faecalis HL-6 by Southern blot analyses. The antigenic components of E. faecalis HL-1, HL-6, R-1 and R-6 strains were analyzed by SDS-PAGE and immunoblotting. The E. faecalis strains had 7 to 16 polypeptide bands, however their major proteins were 97.8 and 26.8 Kd. At the Immunoblotting, 97.8, 95.8, 74.8, 63.5, 33.7 and 26.8 Kd polypeptides of the strains showed major antigenic activities with patient's sera infected intra-abdominally with an E. faecalis strain.

• The Korean Journal of Food And Nutrition
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• v.14 no.6
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• pp.548-561
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• 2001

Listeria spp. from sea water, fishes and shellfishes have been troubled in many countries. So we exam ined its distribution rates, biochemical characteristics of a separated strain, growth curve of pH at set times to 4 species of standard strain, and yes or no of growth inhibition for precautionary measure of food poisoning by L. monocytogenes, garlic, mustard, wasabi, and green tea extracts including sensitivity of antibiotics 10 species. As its results, check numbers of its positivity to Listeria spp. were 32 species in total examination body 200 species, and its isolation rates were 16%, L. innocua was 14.0%, L. monocytogenes 1.0%, and L. seeligeri 1.0% by the strain species. All the standard strain of 4 species showed growth inhibition bellow pH 3.0, its pH conditions of the optimum growth at 7.0∼8.0, and its growth was more active in alkali co]tuition than in acid condition. Its growth inhibition examination by garlic extracts had an the worst effects with O.D values of 0.078∼0.210. But the case of mustard and wasabi had weakened effect, and the case of green tea had some effect as the time went by. The results of sensitivity examination of antibiotics 10 species were as fellows. L. innocua of the 16 cases showed sensitivity of 100% in all 5 species, Ampicillin, etc, and Ciprofloxacin showed sensitivity of 43.7% and gentamicin, 93.7%. But tetracycline showed tolerance of 31.3% , cefotaxine. 75%, nalidixic acid, 100%. L. monocytogenes of the 6 cases showed sensitivity of 100% in all 6 species, ciprofloxacin, etc.

• Korean Journal of Environmental Biology
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• v.17 no.4
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• pp.439-448
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• 1999

To investigate the population dynamics and survival of Genus Vibrio, population densities of aerobic saprophytic bacteria and Vibrio groups were measured 4 times in the intertidal waters of the Yellow Sea near Kunsan from November, 1997 to June, 1998. The distribution of heterotrophic bacteria during the survey periods by plate count and direct count method ranged from 1.2$\pm$0.6$\times$10$^3$~2.0$\pm$1.5$\times$10$^4$CFU ml­$^1$and from 6.0$\pm$4.0$\times$10$^{5}$ ~1.9$\pm$1.5$\times$10$^{7}$ cells ml­$^1$, respectively. Vibrio groups were distributed in the range of 1$\times$10 and 6$\pm$2.2$\times$10$^2$CFU ml­$^1$. The proportion of Vibrio groups to total heterotrophic bacteria was between 0.1 and 6% during the survey periods. A total of 51 isolates was obtained from TCBS agar plates and identified to species level by Biolog Identification System$^{TM}$. As a result, dominant genera were V, mediterranei, V aitguillarum, tr metschnikovii, and V. parahaemolyticus, and isolates were clustered into 26 groups based on the relatedness of average linkage clustering method at 70% level. As for the susceptibility of 51 isolates to 7 kinds of antibacterial agents (gentamicin, ampicillin, chlorarnphenicol, streptomycin, kanamycin, tetracycline, carbenicillin), 96% of isolates showed high resistance to more than one antibiotics and 65% of isolates contained a plasmid, of which size was observed greater than 12 kb, The number of cells of 3 tested strains (V. anguillarum, V. vulnificus, and V. metschnikovii) in filtered aged seawater decreased by approximately 1 to 5 orders of magnitude during 30-d incubation. In most cases, the numbers of cells decreased rapidly until day 3, then decreased slowly by day 30. The number of cells incubated at 15$^{\circ}C$ showed higher survival than those at 4$^{\circ}C$ and $25^{\circ}C$. These results may be considered for the basic supporting data in the risk assessment of vibriosis in summer.r.

• Korean Journal of Environmental Agriculture
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• v.12 no.1
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• pp.41-49
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• 1993

The Study was conducted to develope the low temperature tolerant methane-producing bacteria(LTTB) and to increase the efficiency of anaerobic fermentation for the treatment of agricultural and livestock wastes at low temperature. The samples were collected from muddy soil, water logged sediment, organic layer and anaerobic sludge at three latitudes, $34.8{\sim}37.4\;^{\circ}N(Korea)$, $41.4\;^{\circ}N(USA)$ and $54.5{\sim}56.9\;^{\circ}N(Canada)$. They were used for determination of the methanogenesis rates for isolation and identification of the LTTB. The methanogenesis rate of smaples at low temperature were higher in the cellulose medium than methanol medium. The methanogenesis rate in the samples of subarctic region were $15{\sim}19$ moles/ml during 30 days at low temperature($8\;^{\circ}C$), whereas not detected in the samples of temperate region. The methanogenesis rate in the enrichment culture of subarctic samples were inhibited by the $40\;{\mu}g/ml$ of streptomycin + vancomycin or ampicillin + oleandomycin which were not effect to the methanogens. An inhabitation of high temperature tolerant methane producing bacteria was identified in the samples of temperate region, whereas that of the LTTB growing at $8{\sim}13^{\circ}C$ was identified in the subarctic region.