• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.3
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• pp.220-226
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• 2014

Sixty-seven Vibrio parahaemolyticus isolates from surface seawater from the Wando area, on the southern coast of Korea, were analyzed for their susceptibility to 15 different antimicrobials and the presence of virulence genes. According to the disk diffusion susceptibility test, all of the strains studied were resistant to ampicillin and oxacillin, while decreasing percentages were resistant to vancomycin (64.2%), streptomycin (56.7%), amikacin (31.3%), kanamycin (22.3%), cephalothin (20.9%), erythromycin (10.4%), ciprofloxacin (4.5%), and tetracycline (3.0%). All of the strains were susceptible to five antimicrobials: chloramphenicol, gentamycin, nalidixic acid, sulfamethoxazole/trimethoprim, and trimethoprim. Fifty-nine isolates (88.1%) were resistant to three or more classes of antimicrobial and defined as multidrug resistant, and two strains were resistant to seven antimicrobial agents. The minimum inhibitory concentration (MIC) of the 67 V. parahaemolyticus isolates to ampicillin and oxacillin ranged from 512-2,048 and $64-512{\mu}g/mL$, respectively. All 67 isolates were also examined for the presence of the tdh and trh virulence genes using the polymerase chain reaction (PCR). However, no isolates possessed either tdh or trh. The VPA0477 (${\beta}$-lactamase) gene, present in all of the tested strains, was validated as a new specific marker gene in PCR assays for the accurate detection and identification of V. parahaemolyticus.

• Korean Journal of Veterinary Research
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• v.20 no.2
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• pp.113-118
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• 1980

Total of 11 strains of Ldctobacillus isolated from lactobacillus-fermented milk and-beverage in March 1980 were examined for susceptibility to 8 drugs, and transferability and transfer frequency of R plasmids by conjugation. Of 11 isolates each 2 strains were classified as L. cellobiosus and L. helveticus, each 1 strain as L. plantarum, L. lactis, L. acidophilus, L. delbrueckii, L. casei subsp. casei, L. casei subsp, tolerans and L. salivarius subsp, salivarius by Bergey's manual. Resistance was the most active to na lidixic acid(NA), followed in decreasing order by chloramphenicol(CP), ampicillin(AP), kanamycin(KM) and streptomycin(SM). All of isolates were resistant to NA, each 10 strains to CP and AP, 7strains to KM and 6 strains to SM, indicating all of the isolates were resistant to two or more drugs in combination. No strain was resistant to erythromycin(EM), penicillin(PC) and tetracycline(TC). The most frequently encountered resistant patterns were CP NA AP SM KM, followed by CP NA AP KM, NA AP, CP NA, CP NA AP and CP NA AP SM in order. Transfer experiment of drug resistance showed that of 11 resistant strains, 9 strains transferred parts of their resistance to AP or AP CP or SM AP, indicating 9 strains carried R plasmids determining R(AP), R(AP CP) and R(SM AP). The conjugal frequency of R(AP) from Lactobacillus to E. coli ranged from 2.5{\times}10^{-1} to $5.6{\times}10^{-4}%$, that of R(CP) ranged from 5.0{\times}10^{-1} to 5.0{\times}10^{-3}% and that of R(SM) ranged from 6.0{\times}10^{-5} to 1.4{\times}10^{-5}%, at $37^{\circ}C$ for 18 hours of incubation.

• Food Science of Animal Resources
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• v.40 no.5
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• pp.758-771
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• 2020

This study was to investigate the prevalence and characteristics of antimicrobial-resistant Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) from 4,264 retail meat samples including beef, pork, and chicken in Korea between 2013 and 2018. A broth microdilution antimicrobial susceptibility testing was performed for S. aureus. Molecular typing by multilocus sequence typing (MLST), spa typing, and pulsed-field gel electrophoresis (PFGE), was performed on mecA-positive S. aureus strain. S. aureus was isolated at a rate of 18.2% (777/4,264), of which MRSA comprised 0.7% (29 strains). MLST analysis showed that 11 out of the 29 MRSA isolates were predominantly sequence type (ST) 398 (37.9%). In addition, ST72, ST692, ST188, ST9, and ST630 were identified in the MRSA isolates. The spa typing results were classified into 11 types and showed a high correlation with MLST. The antimicrobial resistance assays revealed that MRSA showed 100% resistance to cefoxitin and penicillin. In addition, resistance to tetracycline (62.1%), clindamycin (55.2%), and erythromycin (55.2%) was relatively high; 27 of the 29 MRSA isolates exhibited multidrug resistance. PFGE analysis of the 18 strains excluding the 11 ST398 strains exhibited a maximum of 100% homology and a minimum of 64.0% homology. Among these, three pairs of isolates showed 100% homology in PFGE; these results were consistent with the MLST and spa typing results. Identification of MRSA at the final consumption stage has potential risks, suggesting that continuous monitoring of retail meat products is required.

• Clinical and Experimental Pediatrics
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• v.45 no.3
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• pp.346-353
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• 2002

Purpose : Penicillin- and multidrug-resistant S. pneumoniae poses a serious threat to clinicians because the rate of resistance of S. pneumoniae to penicillin in Korea has surged up to the world's highest level. This study was performed to assess the carriage rate, serogroups and antimicrobial susceptibility of S. pneumoniae isolated from oropharynx in children. Methods : From March to July 1998, 209 children under 5 years of age were recruited from five day care centers. The carriage rate for pneumococci was obtained. Antimicrobial susceptibilities were determined with the E-test and agar dilution methods. Serogrouping was performed on 48 of the pneumococcal isolates by the Quellung reaction. Results : The carriage rate of S. pneumoniae was 30.1%. Antimicrobial susceptibility profiles were available for 59 of the isolates. Sixty-six percent of isolates were not susceptible to penicillin, and multidrug-resistance was observed in 76.3% of the isolates. A high proportion of the penicillin-resistant strains showed associated resistance to trimethoprim-sulfamethoxazole, tetracycline, erythromycin, and oxacillin. The most prevalent oropharyngeal serogroups were 19, 6, 3, 23, and 29. Resistance of the pneumococcal isolates to penicillin was different according to the serogroups. All of the strains of serogroup 19, 23, and 29 was resistant to penicillin but 87.5% of serogroup 3 strains were susceptible to penicillin. Conclusion : The resistance rate of S. pneumoniae isolated from oropharynx in children was very high to penicillin and other antimicrobial agents. For the reduction of the drug-resistant rate of S. pneumoniae, clinicians should be required to be more judicious in their use of antimicrobial agents.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.4
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• pp.335-342
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• 2016

Staphylococcus aureus, which is generally susceptible to the involvement route in community, is mostly MSSA. However, CA-MRSA is recently increased. Abuse of antibiotics and glycopeptides may increase VISA and VRSA. This study was conducted to investigate the changes on the antibiotic resistance prevalence and antibiotic susceptibility patterns of Staphylococcus aureus isolated from the wound of patients in a university hospital for the past 10 years. This study showed that antibiotic resistance was higher in males than in females; moreover, the antibiotic resistance rates increased with age. The resistance rate for penicillin, oxacillin, erythromycin, gentamicin, clindamycin, tetracycline, ciprofloxacin, fusidic acid, trimethoprim/sulfamethoxazole, clindamycin, and rifampicin was, respectively, 97.7%, 60.5%, 57.4%, 48.8%, 41.1%, 44.2%, 44.2%, 14.7%, 13.2% and 3.9% in 2006. The resistance rate for penicillin, oxacillin, erythromycin, gentamicin, clindamycin, tetracycline, ciprofloxacin, fusidic acid, trimethoprim/sulfamethoxazole, fusidic acid, clindamycin, and rifampicin was, respectively 95.9%, 62.6%, 55.7%, 28.6%, 50.3%, 34.7%, 38.8%, 34.0%, 2.7% and 8.2% in 2016. Vancomycin, linezolid, quinupristin/dalfopristin, and teicoplanin exhibited 100% in antibiotic susceptibility. In particular, fusidic acid resistance was increased by 19.3% in 2016. Compared with 2006, the decreased point, 12.4% was susceptible and was statistically significant. Therefore, this study suggests that periodic review and understanding of microbial and antibiotic changes should continue to investigate appropriate antibiotic susceptibility.

• Korean Journal of Veterinary Research
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• v.29 no.3
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• pp.393-405
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• 1989

This study was carried out to treatment test for bovine mastitis by the determination of adenosine triphosphate (ATP) based on firefly bioluminescence. The results obtained are followed; 1. In the susceptibility test, cephalothin which looks the most effective were sensitive to Staphylococcus sp. (72.3%), Micrococcus sp. (84.2%), Streptococcus sp. (72.7%) and Gram positive bacilli (72.7%), Gram negative bacilli were sensitive to gentamicin (92.3%) and Yeast-like-fungi was the most sensitive to clotrimazole, and nystatin in order. 2. When the number of bacteria, such as Staphylococcus aureus, Candida tropicalis isolated from the mastitis milk were counted by conventional agar plating technique, and compared with the concentration of bacterial ATP, it gave a good linear relationship. The content of ATP per Staphylococcus aureus, cell was 3.1fM and Candida tropicalis showed the high level of A TP (90fM). 3. The ATP assay was applied to the determination of minimal inhibitory concentration (MIC) of various antibiotics. When Staphylococcus aureus was incubated in the presence of different concentration of tetracycline, erythromycin, kanamycin and streptomycin sulfate and the growth was monitored by the conventional agar plating technique and ATP assay, both methods shown the same results that they were 1mcg/ml, 2mcg/ml, 6.25mcg/ml and 8mcg/ml, respectively. 4. For the determination of susceptibility of sensitive and resistant Staphylococcus au reus isolated for the milk with mastitis to tetracycline, erythromycin kanamycin and streptomycin sulfate, the minimum time required for the test was determined by the assay of ATP every 30 minutes during incubation of 3 hours at $37^{\circ}C$. ATP concentration time curve calculated on both resistant and sensitive strains incubated 3 hours as the optimum time for the determination of susceptibilities of various antibiotics exemed. The ATP concentration of each test broth (antibiotic containing), expressed as a percentage of its own control brith (antibioticfree) indicated values of 30% to be indicative of each antibiotic sensitivity. Single time point ATP assay carried out on the various sensitive and resistant of Staphylococcus aureus to antibiotics examined after 3 hours at $37^{\circ}C$ correlated exactly with disc diffusion and MIC. 5. In the cure of intramammary treatment of bovine mastitis in lactating quarters, the cure rate of Staphylococcal mastitis showed to cephalexin (80%), cloxacillin and gentamicin (70%), ampicillin and oxytetracycline (60%), and Streptococcal mastitis showed to cephalexin (85%), penicillin (80%), cloxacillin and oxytetracycline (75%), and ampicillin (70%), but intramammary antimycotic drug (clotrimazol) were only a little effect about fungal mastitis.

• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.295-303
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• 2006

To provide microbial information for the safety of agricultural production, the presence of enterotoxin genes and antibiotic susceptibility of 14 isolated Staphylococcus aureus (11.7%) strains were investigated using PCR-based methods and disk diffusion method, respectively. Among enterotoxin-encoding genes, sea was detected from two isolates (14.3%), sea and sed genes were co-detected from three isolates (21.4%), and sea, sed, and see genes in seven isolates (50.0%), whereas seb, sec, and tsst were not detected in any isolate. Nine (64.3%), eight (57.1%), six (42.9%), two (14.3%), and one (7.2%) isolates were resistant to penicillin, novobiocin, amphicillin, erythromycin and oxacillin, and doxycycline and kanamycin, respectively. Methicilline-resistant S. aureus was found in roller of B farm and in hydroponic solution of D farm.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.714-720
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• 2012

To evaluate the antibiotic risk of $Enterococcus$ in fermented soy paste, $Enterococcus$ spp. were isolated and identified from 31 $Cheongkukjang$ and 17 $Doenjang$, samples. Exactly 123 $Enterococcus$ spp., 119 from $Cheongkukjang$ and four from $Doenjang$, were ultimately isolated. The most frequently collected $Enterococcus$ isolates in $Cheongkukjang$ were 69 strains of $E.$ $faecium$ and 20 strains of $E.$ $faecalis$. All four $Enterococcus$ spp. from $Deonjang$ were identified as $E.$ $faecium$. All isolates were sensitive to ampicillin, chloramphenicol, penicillin, and tetracyclin $E.$ However, they showed broad spectra from sensitivity to resistance to erythromycin, ripampin, and streptomycin. Vancomycin minimum inhibition concentration (MIC) of $Enterococcus$ spp. from $Cheongkukjang$ ranged from 0.25 to 8 ${\mu}g/mL$. Almost all strains were sensitive to vancomycin, but eight strains showed intermediate resistance to vancomycin. Seventeen strains showing the highest MIC of 8 ${\mu}g/mL$ among all isolates were evenly distributed among $E.$ $faecalis$, $E.$ $faecium$, $E.$ $gallinarum$, and $E.$ $casselifalvus$, in which the strong resistant genes of $van$A and $van$B for vancomycin were not detected. Overall antibiotic resistance of $Enterococcus$ isolates was relatively low and particularly low vancomycin resistance was similar to those of $Enterococcus$ isolates obtained from other foods. Therefore, the antibiotics resistance of $Enterococcus$ and especially vancomycin-resistant $Enterococcus$ spp. from $Cheongkukjang$ and $Doenjang$, is not hazardous.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3315-3322
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• 2015

Staphylococcus aureus is the major causative organism of nasocomial infection being the important pathogen in the clinic. Appearance of staphylococcus aureus resistant to methicillin (MRSA) is becoming a big problem in clinics and dynamics all over the world acquiring antibiotic resistance with virulence factors as its feature differentiated from other pathogenic bacteria fast. This research intended to compare and analyze the correlation of antibiotics resistance between strains with toxin genes and distribution of toxin genes of MRSA 101 strains acquired from clinical specimen in one general hospital (enterotoxin(se), toxic shock syndrome toxin-1(tst), exfoliative toxin(et), Panton Valentine leukocidin(pvl)). seg gene, isolated the most among toxin genes, was detected in 59 strains (58.4%) and more than two toxin genes were detected in 70 strains (69.3%). As a combination possessing toxin genes, it was detected in 19 strains (18.8%) as seb, sec, seg, sei, tst and the second frequent combination was sec, seg, sei shown in 11 strains (10.9%). 19 strains (18.8%) with combinations of toxin genes same with seb, sec, seg, sei, tst had 100% resistance Ampicillin, Benzylpenicillin, Ciprofloxacin, Clindamycin, Gentamicin, Erythromycin, Telithromycin, Tetracycline antibiotics. Strains with many toxin genes showed high correlation of antibiotic resistance. Afterwards, effective therapy and thorough infection management should be preceded not to spread the resistance of MRSA strain.

• 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.