• 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.

• The Journal of the Korean Society for Microbiology
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• v.13 no.1
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• pp.63-73
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• 1978

28 strains of Enterococci isolated at doctorless areas in Korea from Oct. 1976 through Mar. 1977 and 30 strains of Enterococci isolated at Seoul National University Hospital from Sep. 1976 through Dec. 1976 were examined for susceptibilities to 14 antimicrobial agents by agar dilution method. The susceptibilities of two groups to each antimicrobial agent were compared and incidence of resistant strains in each antimicrobial agent, incidence of multiply resistant strains and correlations in the antimicrobial susceptibility of 58 strains of Enterococci among 14 antimicrobial agents were analyzed. 1. With Tetracycline, Oxytetracline, Doxycycline, Minocycline and Erythromycin, the mean MIC's of Enterococci isolated at Seoul National University Hospital were 1.9-2.5 times higher than those of Enterococci isolated at doctorless areas, though there were no statistical significance. 2. Frequency of resistant strains in Enterococci isolated at Seoul National University Hospital was the highest with Cephalexin(100%), Gentamicin(100%), and Streptomycin(100%), followed by Kanamycin(93.3%), Carbenicillin(90%), Tetracycline(26.7%), Oxytetracycline(26.7%), Doxycycline(26.7%), Minocycline(20%), Erythromycin(10%), Troleandomycin(10%), Penicillin(6.7%), Cotrimoxazole(6.7%) and Ampicillin(0%). 3. Frequency of resistant strains in Enterococci isolated at doctorless areas was the highest with Kanamycin(100%) and Streptomycin(100%), followed by Cephalexin(96.4%), Gentamicin(96.4%), Carbenicillin(92.9%), Tetracycline(10.7%), Oxytetracycline(10.7%), Doxycycline(10.7%), Minocycline(10.7%), Cotrimoxazole(10.7%), Penicillin(3.6%), Ampicillin(0%), Erythromycin(0%), and Troeandomycin(0%). 4. In study with Penicillin, Ampicillin, Tetracycline, Cotrimoxazole, Erythromycin and Troleandomycin, there were no multiply resistant strains in Enterococci isolated at doctorless areas, while 4 strains of Enterococci isolated at Seoul National University Hospital showed multiple resistance. 5. There were high correlation in susceptibility of 58 strains of Enterococci among Tetracycline, Oxytetracycline, Doxycycline and Minocycline(correlation coefficients 0.86-0.97). Correlation coefficients of susceptibility among penicillin analogues(Penicillin, Ampicillin, Carbenicillin and Cephalexin) ranged between 0.75-0.89. Correlation coefficients of susceptibility among aminoglycosides(Kanamycin, Gentamicin and Streptomycin) ranged between 0.09-0.51.

• Korean Journal of Microbiology
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• v.31 no.4
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• pp.267-273
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• 1993

We screened promoters inducible by superoxide radical from Escherichia coli. For this. we constructed random promoter library from E. coli MG 1655 using a promoter-probing plasmid. pJAC4. Six hundred and sixty clones in this library were classified based on their promoter strength by ampicillin gradient plate assay. Three hundred and eighty three clones with relatively weak to medium promoter strength were selected and then screened for their inducibility by superoxide radical on ampicillin gradient plate containing paraquat. Three clones (clones 5. 15 and 34) were detected to be induced by paraquat treatment and the level of induction were between 1.4 and 4 folds. Comparison of nucleotide sequences of the cloned promoter fragment with registered sequences in GENBANK and EMBL databases suggests that the cloned DNA fragments have not been yet characterized in E. coli. Transcription start sites in these clones were determined by rrimer extension and S I nuclease protection analysis. S 1 analysis of clones 5 and IS indicated that the mRNA levels were increased by paraquat treatment. Especially. clone 5 \vas found to have two transcription start sites. the upstream start site of which was selectively used by paraquat treatment. Searching for promoter clements. we found that only the downstream promoter of clone 5 has -10 and - 35 promoter elements recognized by RNA polymerase ($E\sigma^{70}$) and the others have no conserved promoter elements. This suggests that these superoxideinducible promoters may require transcription initiation protein(s) other than $E\sigma^{70}$.

• Journal of Veterinary Clinics
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• v.19 no.3
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• pp.303-311
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• 2002

Isolation and identification of causative microorganisms and susceptibility testing are important in selecting appropriate antimicrobial agent. The purpose of this study was to determine the antimicrobial susceptibility patterns and identification of bacteria for the selection of a therapeutic antibiotic agent for treatment. Specimens were cultured aerobically from dog patients brought to the veterinary medical teaching hospital of Seoul National University between July 1999 and September 2000. A total of 157 isolates were from skin(63), urine(45), ear canal(31) and conjunctiva(18). The result is that the most common organisms isolated from dog patients were S. intermedius was the most common isolates from the skin, ear canal, and conjunctiva. E. coli was the most common isolated from urine. Most of gram-positive isolates were resistant to ampicillin(80.6%), erythromycin(68.8%), penicillin(86.2%), tetracycline(89.2%). Otherwise most of gam-negative isolates were resistant to ampicillin(73.4%), trimethoprim-sulfa(53.3%). E. coli was resistant to ciprofloxacin(61.5%), piperacillin (69.2%). Antimicrobial susceptibility pattern by the sampling site was not remarkably different except 5. aureus isolated from urine.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.5 no.1
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• pp.33-38
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• 2002

Purpose: The incidence of shigellosis had been decreased due to the use of antibiotics and the improvement of environmental sanitation but recently increases again. Shigellosis occurrs in mass outbreak through unsanitized meal preperation refered from welfare facility and school. We observed epidemic aspect and clinical coarse of childhood shigellosis. Methods: from December 2001 to January 2002, 22 inpatients with shigellosis in Dongbu Municipal Hospital were observed epidemiologically, clinically and microbiologically. Results: 1. The sexual ratio was 1:1 and mean age was $5.5{\pm}1.4$ years (14 months to 11 years). 2. The clinical manifestations were following: diarrhea (95.5%), high feve (10%) and asymptomatic (4.5%). The mean duration was $3.9{\pm}2.1$ days (1 to 12 days). All patients had no complication and normal serologic test. 3. S. sonnei was cultured in rectal swab, and was resistant to TMP/SMX and ampicillin, but susceptible to ampicillin/sulbactam and the 3rd generation cephalosporins. 4. The patients were treated by antibiotics with conservative treatment including electrolytes and fluid therapy for 5 days, resulting in improvement confirmed by negative reaction on stool culture. 5. These cases were all occurred in mass outbreak in day care center and were suspected to be secondary infection by members of family. Conclusion: This shigellosis occurred in day care center was secondary infection due to S. sonnei and had mild clinical coarse and improvement after antibiotic treatment.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.941-947
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• 2005

The contamination frequency of major foodborne pathogenic bacteria was investigated from 213 seafood samples including sliced raw fish and shellfish in Busan and CyeongNam province area. Tested microorganisms were Salmonella spp. Staphyloroccus aureus, Vibrio parahaemolyticus, Escherichia coli O157:H7, Bncillus cereus, Listeria monocytogenes and Campylobacter jejuni. The frequency of isolated microorganisms was V. parahaemolyticus (30.5%), B. cereus (9.9%), S. aureus (3.8%) and other pathogenic bacteria (1.4%). from July to October, total isolation rates were greater than 50% and V. parahaemolyticus was dominant among the microorganisms isolated. The bacteria isolation rate (49.2%) in raw seafoods including shellfishes was higher than one (28.9%) in sliced raw fish. V. parahaemelyticus isolates were resistant to ampicillin (96.9%), amikacin (29.2%) and tetracycline (27.7%), and B. cereus isolates were resistant to ampicillin (100%), Penicillin G (100%), rifampicin (71.4%) and tetracycline (14.3%). The growth of V. parahaemolyticus and B. rereus was greatly inhibited below $10^{\circ}C$, but increased at ambient temperature. Washing seafood with tap water showed to reduce total count of remaining V. parahaemolyticus. Thus temperature control under $10^{\circ}C$, sufficient washing and prompt eating appeared to reduce the risk of food poisoning by these bacteria in seafoods.

• Journal of Food Hygiene and Safety
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• v.36 no.6
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• pp.520-527
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• 2021

In this study, toxin gene and antibiotic resistance of food poisoning strains isolated from indoor air in the cafeteria were analyzed to prevent food poisoning. Staphylococcus aureus (16 strains) and Bacillus cereus (37 strains) isolated from indoor air in child care center were tested. The toxin genes of S. aureus and B. cereus were detected by PCR assay. The antimicrobial susceptibility test followed the disc diffusion method described by the Clinical and Laboratory Standard Institute. The seg and sei toxin genes were detected in 11 of 16 S. aureus strains (68.6%). The nheA and nheB toxin genes were detected in 37 B. cereus strains. In this study, a total of 12 toxin gene patterns of B. cereus were found, among which the nheA-nheB-nheC toxin gene was found to be the most frequent pattern. The result of the antimicrobial susceptibility test of S. aureus revealed 93.8% and 87.5% resistance to ampicillin and penicillin antibiotics, but methicillin resistance S. aureus and vancomycin resistance S. aureus were not detected. All 37 B. cereus tested in this study were resistant to ampicillin and penicillin antibiotics. Based on the result of this study, it was judged that regular ventilation and air quality management were necessary to prevent food poisoning caused by S. aureus and B. cereus contaminated in the indoor air of child care centers.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.4
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• pp.497-504
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• 2022

The purpose of this study is to evaluate the antibacterial effects of two liquid fluoride materials on Streptococcus mutans (S. mutans). Riva star aqua^TM (SDI, Bayswater, Australia), which consists of silver fluoride (AgF, step 1) and potassium iodide (KI, step 2), and Fluor protector^® (FP; Ivoclar Vivadent, Liechtenstein) were used for experimental groups. Experimental groups were divided into 4 groups : AgF, KI, AgF + KI and FP. For the positive control (PC) group, ampicillin was used, and the negative control group (NC) did not receive any additional treatment. Each group was divided into 30 and 50 µL groups by volume of liquid and applied to flat-coated S. mutans. The diameter of the zone of inhibition was measured. The PC and AgF groups showed larger diameters than other materials (p < 0.05), and the AgF group showed no significant difference from the PC group in the 50 µL group (p > 0.05). The FP group showed larger diameters than the AgF + KI group in the 30 µL (p = 0.009). The KI group did not show significant difference from the NC group (p > 0.05). AgF is comparable to ampicillin in antibacterial effects on S. mutans, and better than FP.

• Korean Journal of Microbiology
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• v.25 no.2
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• pp.87-93
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• 1987

The properties of the plasmid pKU41 isolated from Pseudomonas putkda KU190 have been investigated, pKU41 was defined as an R plasmid having a transmissible ampicillin and tetracycline resistance determinant, and could be classified as a plasmid belonging to IncP-1 group according to incompatibility grouping.

• Korean Journal of Veterinary Research
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• v.49 no.3
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• pp.195-200
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• 2009

Avian pathogenic Escherichia coli (APEC) is an important bacterial pathogen of chickens and causes colibacillosis such as airsacculitis, perihepatitis, omphalitis, peritonitis, salpingitis, and pericarditis. As the transfer of antibiotic resistance from animal to humans can be possible, surveillance on antibiotic resistance of APEC is very important. A total 34 APEC isolates from diseased chickens during the period from 2007 to 2009 were obtained. The susceptibility of the isolates to 13 antibiotics was determined by disc diffusion assay. Resistance to erythromycin was found in 97.1% of APEC isolated, followed by resistance to tetracycline (85.3%), doxycycline (82.3%), ampicillin (73.5%), sulfisoxazole (67.6%), enrofloxacin (67.6%), ciprofloxacin (64.7%), norfloxacin (61.7%) trimethoprim/sulfamethoxazole (52.9%), gentamycin (26.5%), amoxicillin (8.8%), colistin (5.9%), and amikacin (2.9%). The blaTEM genes were detected in 25 (100%) of the 25 ampicillin-resistant APEC isolates. Among the 29 tetracycline-resistant APEC isolates, tetA and tetB genes were detected in 18 (62.1%) and 9 (31%) isolates, respectively. Twenty six (76.5%) isolates were multiresistant to at least 6 antibiotics and seven (20.1%) isolates were multiresistant to at least 10 antibiotics. This results indicated that multiple antibiotic-resistant APEC is widespread in chicken flocks in Korea.