• Korean Journal of Environmental Agriculture
• /
• v.42 no.3
• /
• pp.169-176
• /
• 2023

The emergence and spread of antibiotic-resistant bacteria have been increasing with anthropogenic contamination. Understanding the prevalence and distribution of these resistant bacteria in environments is crucial for effectively managing anthropogenic pollutants. Lake Gyeongpo in the Gangwon Province of South Korea is known for its diverse ecological features and human interactions. The lake is exposed to pollutants from nonpoint sources, including urban areas, agricultural practices, and recreational activities, which can introduce antibiotics and foster antibiotic resistance in bacteria. The present study investigates Lake Gyeongpo as a potential reservoir for antibiotic-resistant bacteria in a natural ecosystem. A total of 203 bacterial isolates were collected from six sampling locations in Lake Gyeongpo during May, July, and November 2022. Most isolates were taxonomically identified as Pseudoalteromonas, Bacillus, Shewanella, and Vibrio spp.; their abundance showed a spatiotemporal distribution. An antibiotic susceptibility test was conducted on 75 isolates using the disk diffusion method with six drugs according to the CLSI guideline; 42 isolates were resistant to one or more antibiotics. Among these, 15 isolates were identified as multidrug resistant bacteria. This finding suggests the potential anthropogenic impact on Lake Gyeongpo and provides valuable insights into the dissemination of antibiotic resistance caused by anthropogenic pollutants.

• The Journal of the Korean Society for Microbiology
• /
• v.8 no.1
• /
• pp.13-17
• /
• 1973

To understand the characteristics of 29 toxigenic strains of Corynebacterium diphtheriae isolated in Seoul area, type classification, biochemical properties and antibiotic susceptibility pattern to 9 kinds of antibiotics were investigated. The results obtained were summerized as follows; I. Among the 29 strains, gravis type was the overwhelming majority(24 strains), followed by intermedius type(3 strains) and mitis type(2 strains). II. Fermentation of glucose, maltose, lactose, trehalose and mannitol, nitrate reduction and urease were tested. All strains fermented glucose, but not sucrose, lactose, mannitol and trehalose. 9 strains fermented maltose and 20 strains did not. Nitrate was reduced by 28 strains but not by one strain. In urease test one strain showed positive, 28 strains negative. III. Antibiotic susceptibility test to penicillin G, chloramphenical, kanamycin, lincomycin, streptomycin, terramycin, erythromycin and gentamycin were carried out. The MIC of erythromycin(0.025 ${\mu}g/ml$ 26 strains and 0.05 ${\mu}g/ml$ 3 strains) was the lowest, followed by ampicillin, lincomycin and penicillin G. Streptomycin showed the highest MIC.

• The Journal of Korean Obstetrics and Gynecology
• /
• v.19 no.3
• /
• pp.175-190
• /
• 2006

Purpose : This study was conducted to investigate the in vitro inhibitory effects of heat-clearing medicinal on common bacterias in gynecology. Methods : The heat-clearing medicinals ( Trichosanthis Radix, Sophorae Fructus, Phragmitis Rhizoma, Buddleiae Flos, Bambusae Folium, Anemarrhenae Rhizoma, Celosiae Semen, Gardeniae Fructus, Prunellae Spica, Sophorae Radix, Dictamni Radicis Cortex, Coptidis Rhizoma, Gentianae Scabrae Radix, Scutellariae Radix, Phellodendri Cortex) were used in this study. Staphylococcus aureus, MRSA, Candida albicans and Gardnerella vaginalis were used for vaginal pathogenic microorganisms. Streptococcus spp., Escherichia coli HB101, Lactobacillus gasseri were used for normal vaginal florae. We evaluated antibiotic effect by the optical density and the colony test. Results : The optical density and colony test showed that Celosiae Semen, Prunellae Spica, Scutellariae Radix and Phellodendri Cortex of herbs among heat-clearing medicinal had antimircobial effect. Celosiae Semen and Prunellae Spica had antimicrobial susceptibility and selective toxicity in MRSA. Scutellariae Radix and Phellodendri Cortex had antimicrobial susceptibility and selective toxicity in Gardnerella vaginalis. Conclusion : According to the above results, we could suggest that Celosiae Semen, Prunellae Spica, Scutellariae Radix and Phellodendri Cortex among heat-clearing medicinal be available to antimicrobial agent of vaginal pathogenic microbial species in vitro.

• Journal of Veterinary Clinics
• /
• v.25 no.5
• /
• pp.346-354
• /
• 2008

The combined effects of EDTA-Tris and eighteen antimicrobial agents have been evaluated in eight clinically isolated methicillin-resistant bacteria (Staphylococcus aureus, Escherichia coli, Streptococcus uberis and Streptococcus agalactiae) from bovine mastitis. The antimicrobial activity was evaluated by measuring the minimal bactericidal concentration (MBC) for the antibiotics alone or in combination with EDTA-Tris in Mueller-Hilton broth and milk. Combined use of EDTA-Tris and antibiotics potentiated or antagonized activity of antibiotics against mastitic pathogens. Milk increased the antibiotic potency of erythromycin and spiramycin on S. aureus. Culture in milk changed patterns of EDTA-Tris combinational effects compared with that in standard Mueller-Hilton broth. Combined with EDTA-Tris in milk, synergic effects were observed in colistin, dihydrostreptomycin, kanamycin, erythromycin, gentamycin, oxytetracycline, streptomycin to E. coli, Str. uberis, and Str. agalactiae. However, significant antagonistic effects of milk on antibiotic susceptibility in combination with EDTA-Tris were noted in neomycin, streptomycin, penicillin, roxithromycin, and amoxicillin. This study indicates that combination therapy of EDTA-Tris with antibiotics in bovine mastitis should be used with caution because of the possible antagonistic effects of antibiotic combination with EDTA-Tris on mastitic pathogens. In addition, antibiotic susceptibility test in combination with EDTA-Tris in milk culture condition can be benefit in search of effective treatment regimen for some antibiotic-resistant bacteria of mastitis.

• Journal of Yeungnam Medical Science
• /
• v.10 no.1
• /
• pp.28-36
• /
• 1993

Major pathogenic Gram-negative organisms such as P. aeruginosa, Serratia species, E. coli, Enterobacter species which are isolated from the specimens in large medical centers are greatly resistant to the commonly used antibiotics. Gram-negative bacilli, which had been isolated in Yeungnam University Hospital during the period from December 1992 to April 1993 and turned out to be resistant to the primary antibiotics susceptibility test for chloramphenicol, ampicillin, cephalothin, gentamicin, tetracyclin, amikin and tobramycin, were subjected to the secondary antibiotics susceptibility test for aztreonam, ceftazidime, ciprofioxacine, cefotaxime, cefamandole, piperacillin, ticarcillin and sulfamethoxazole trimethopime. Out of 315 tested organisms, 167 organisms(53%) were resistant to all secondary antibiotics in vitro. Antimicrobial activity of ceftazidime(37.1%), aztreonam(11.%), ciprofioxacine(7.9%) against Gram negative bacilli were slightly more active than other antibiotics tested, while cefamandole was not active to all the Gram-negative bacilli tested. According to the specimens, E. coli was the most frequently resistant organisms to the primary antibiotics from urine, A. baumanii, from respiratory system and wounds, and P. aeruginosa from various specimens. In summary, Gram negative bacilli resistant to the primarily applied antibiotics also were resistant to the secondary antibiotics. Rearrangement of the antibiotics disks for the antibiotic susceptibility test should be considered.

• Korean Journal of Environmental Agriculture
• /
• v.41 no.4
• /
• pp.344-354
• /
• 2022

BACKGROUND: Although antibiotics have contributed to treatment of bacterial infection, the antibiotic abuse can lead to antibiotic resistant bacteria. Impact of human activities on distribution of antibiotic resistance has been intensively issued and occurrence of antibiotic resistant bacteria in contaminated environments would not be a surprise. Nonetheless, anthropogenic contamination with the dissemination of antibiotic resistance along uncontaminated environments has been less considered. The aim of this study is to investigate antibiotic resistant bacteria across Ulleungdo, known as antibiotic resistance free and anthropogenic pollution free environment in Rep. of Korea. METHODS AND RESULTS: Antibiotic resistant bacteria in coastal seawater of Ulleungdo were investigated in July 2021. Antibiotic susceptibility test using the disk diffusion method was applied with six drugs according to the Clinical and Laboratory Standards Institute (CLSI) guideline. Total 43 bacterial isolates were tested and 20 isolates among of them showed multidrug resistance. Particularly, the number and ratio of resistant bacteria were relatively high in a densely populated area of Ulleungdo. The bacterial communities were investigated using 16S rRNA gene metabarcoding approach in the coastal seawater and soils of Ulleungdo. In the bacterial communities, Firmicutes were selectively distributed only in seawater, suggesting the possibility of anthropogenic contamination in coastal seawater of Ulleungdo. CONCLUSION(S): We found antibiotic resistant bacteria in a populated area of Ulleungdo. The occurrence of antibiotic resistant bacteria in Ulleungdo seems to result from the recent anthropogenic impact. Consistent monitoring of antibiotic resistant bacteria in the uncontaminated environment needs to considered for future risk assessment of antibiotics.

• Journal of Veterinary Clinics
• /
• v.34 no.1
• /
• pp.23-26
• /
• 2017

Otitis externa (OE) is an inflammatory disease of the externa auditory meatus that occurs commonly in dogs. Antimicrobial susceptibility tests should be performed in case of chronic OE for successful treatment. In this study, identification and antimicrobial susceptibility test of bacteria isolated from dogs with chronic OE was performed. From 60 dogs with chronic OE, 60 bacterial species were identified. The most frequently identified species were Staphylococcus spp. (51%), followed by Pseudomonas spp. (15%) and Enterococcus spp. (14%). A single bacterial infection and multiple bacterial infections were observed in 67.5% and 32.5%, respectively. Staphylococcus spp. was susceptible to imipenum. Pseudomonas spp. was found to be susceptible to amikacin, cefepime, imipenum and piperacillin-tazobactam. Enterococcus spp. was susceptible to ampicillin-sulbactam, imipenum and piperacillin-tazobactam. Imipenum was highly susceptible antibiotic against both Gram-positive and negative bacteria whereas aztreonam and vancomycin were highly resistant. These results could suggest the optimal choice of antimicrobial agents for canine OE treatment.

• Journal of Microbiology and Biotechnology
• /
• v.9 no.3
• /
• pp.328-333
• /
• 1999

Susceptibility of 61 strains of Helicobacter pylori to metronidazole was examined by both the disk diffusion method using a cut-off of 15㎜ for resistance and the E test with a cut-off of 8㎎/l. The MIC/sub 50/ and MIC/sub 90/ by the E test were 2 ㎎/l and 256㎎/l, respectively. Metronidazole resistance was found in 22 (36％) out of the 61 H. pylori strains by the E test and in three additional strains by the disk diffusion method. Amongst the latter three isolates, the MICs by the E test were 4 ㎎/l, 6㎎/l, and 6㎎/l, respectively. These figures are one log₂ or half log₂ dilution lower than the cut-off of 8㎎/l recommended as resistance for the E test. All 22 metronidazole resistant H. pylori isolates by the E test that were subjected to random amplified polymorphic DNA (RAPD) fingerprinting showed different DNA fingerprints. Interestingly, >90％ of resistant isolates possess two common DNA bands of 0.4 and 0.9 kb. This study demonstrates that the results of the disk diffusion method for testing H. pylori susceptibility to metronidazole correlates well with that of the E test. The criteria for interpretation need to be internationally standardized so that the results from different centers can be compared.

• Korean Journal of Clinical Laboratory Science
• /
• v.37 no.3
• /
• pp.155-163
• /
• 2005

The purpose of this study is to investigate the carrier rate of S. aureus in the community, antibiotic susceptibility patterns of the organism, detection of MRSA and mecA gene in MRSA. Identification and antibiotic resistance patterns of S. aureus and MRSA were done by MicroScan Panels. MRSA strain was confirmed by disk diffusion method using oxacillin disk. The mecA gene in MRSA was detected by PCR. Eighty-four strains (27.4%) of S. aureus were isolated from the nasal specimens of 307 university students in Busan in 2004. Sixty-eight strains (81.9%) of 83 S. aureus were resistant to penicllin, 16 strains(19.3%) to erythromycin, 15 strains (18.1%) to gentamicin, 12 strains (14.5%) to tetracycline, 6 strains (7.2%) to chloramphenicol, 3 strains (3.6%) to ofloxacin, 2 strains (2.4%) to cefepime, clindamycin, imipenem, meropenem, norfloxacin, respectively. One strain (1.2%) was resistant to ciprofloxacin, cefazolin, cefotaxime, cefuroxime, and oxacillin. And all the strains (100%) of 84 S. aureus were susceptible to amoxicilin/K clavulanate, ticarcillin/K clavulanate, trimethoprim/sulfamethoxazole, rifampin, syncroid, teicoplanin, and vancomycin. One strain of 84 S. aureus isolates was methicillin-resistant Staphylococcus aureus (MRSA). The mecA gene was detected from the MRSA strain.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.23 no.1
• /
• pp.81-87
• /
• 2021

Olive flounders which were cultured in commercial fish farm showed abnormal swimming behavior in November 2020. Then, gradual mortality was observed in the fish farm. During the diagnosis, bacterial strain KNCFKW-PN1 was isolated from the kidney of the dead fish. Based on the sequence of gyrase B subunit gene, KNCFKW-PN1 was proved to be Pseudoalteromonas nigrifaciens, showing 99.59% nucleotide identity with that of P. nigrifaciens LMG 2227^T. According to the result of antibiotic susceptibility test, P. nigrifaciens KNCFKW-PN1 showed intermediate resistance to ciprofloxacin, and was resistant to ampicillin, cefepime, cefotaxime, ceftazidime, and amikacin. This is the first report of the isolation of multiple-antibiotic-resistant P. nigrifaciens from olive flounder.