• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.582-588
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• 2016

Seventy-nine Vibrio parahaemolyticus isolates from surface seawater from Gomso Bay, west coast of Korea, were analyzed for the presence of virulence genes and their susceptibility to 30 different antimicrobials. All 79 isolates were examined for the presence of two virulence genes (tdh or trh) using polymerase chain reaction (PCR); however, no isolates possessed either the tdh or trh gene. According to a disk diffusion susceptibility test, all of the strains studied were resistant to oxacillin, penicillin, and vancomycin, followed by ticarcillin (97.5%), ampicillin (96.2%), clindamycin (86.1%), erythromycin (10.1%), streptomycin (7.6%), cefoxitin (6.3%), amikacin (2.5%), and cephalothin (2.5%). However, all of the strains were susceptible to 19 other antimicrobials including cefepime, cefotaxime, chloramphenicol, gentamycin, nalidixic acid, sulfamethoxazole/trimethoprim, and trimethoprim. All 79 isolates (100%) were resistant to four or more classes of antimicrobials, and two strains exhibited resistance to eight antimicrobial agents. The average minimum inhibitory concentrations (MICs) for V. parahaemolyticus for ampicillin, penicillin, ticarcillin, and vacomycin were 946.5, 1,305.9, 1,032.3, and 45.0 µg/mL, respectively.

• Korean Journal of Veterinary Research
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• v.47 no.1
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• pp.33-41
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• 2007

Streptococcus spp. comprising Streptococcus (S.) uberis S. dysgalactiae strains is major causeof bovine mastitis from particularly well-managed or low somatic cell count herds that have successfullycontrolled contagious pathogens. In this study, antimicrobial susceptibility and genetic characteristics of S.uberis isolated from clinical or subclinical mastitis milk at 2003 were investigated. Eighty seven isolatesof Streptococus spp. were identified by the conventional biochemical methods. The antimicrobialsusceptibility by disk diffusion method was determined for 46 S. uberis, 11 S. bovis, 10 S. oralis, 6 S.uberis and 14 other Streptococcus spp.. Overall, the tested strains were susceptible to tetracycline (11.5%),amikacin (14.9%), streptomycin (16.1%), neomycin (26.4%), kanamycin (35.6%), gentamicin (65.2%),oxacillin (70.1%), ampicillin (75.9%), chloramphenicol (78.2%), and cephalothin (97.7%). Additionally, S.uberis strains were susceptible to pencillin G (97.8%), but resistant to erythromycin (76.0%) by minimalinhibitory concentration test. The multiple-drug resistance rate of isolated bacteria to 4 more thanamplification fingerprinting patterns amplifed with primer 8.6d showed that 3 to 8 number of distinguishableDNA fragments ranged from 180 bp to 1,20 bp. Thirty seven isolates of S. uberis strains were subtypedinto 8 distinct patterns. Each subtype revealed a typical pattern of antimicrobial susceptibilities. Thesefindings demonstrate that S. uberis isolates were mastitis pathogens of diverse serotypes, and oftenencountered the diverse resistant patterns.

• Korean Journal of Veterinary Research
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• v.36 no.1
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• pp.181-186
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• 1996

The present study was conducted to investigate the biochemical and serologic characteristic of Actinobacillus pleuropneumoniae isolated from pneumonic lungs of pigs during the period from January 1992 to April 1993. A pleuropneumoniae was isolated from 17(27.0%) of 63 growing pigs with respiratory signs and 21(6.4%) of 330 pneumonic lungs of slaughtered pigs. The seasonal isolation frequency of A pleuropneumoniae was higher in winter and spring than that in summer or fall. The biochemical and cultural properties of A pleluropneumoniae isolated from the pneumonic lungs of pigs were identical to those of the reference strains used. The isolates were highly susceptible to ampicillin, cephalothin, ceftiofur, ciprofloxacin(MIC : ${\leq}0.39{\mu}g/ml$) and moderately susceptible to amikacin, chloramphenicol, erythromycin, kanamycin, methicillin, penicillin-G, streptomycin(MIC : 0.78~25IU or ${\mu}g/ml$), respectively. Sulfadimethoxine, sulfamerazine, tylosine showed no response to the isolates(MIC : ${\geq}100{\mu}g/ml$). Among the 38 isolates, 21(55.3%) and 13(34.2%) were resistant to oxytetracycline aid lincomydn, respectively(MIC : ${\geq}50IU$ or ${\mu}g/ml$). The majority of 38 A pleuropneumoniae isolates were turned out as serotype 2(47.4%) or serotype 5(54.7%) and the remaining 3 isolates were evenly classified to serotype 7, 10 or 12. It was noted A pleuropneumonine serotype 5 isolates were more resistant to oxytetracycline than serotype 2 isolates.

• Journal of Veterinary Clinics
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• v.4 no.1
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• pp.409-421
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• 1987

For the epidemiological studies of the respiratory infection from 1,918 heads of adult rabbits from January 1980 to December 1985 at an integrated farm, the causative agents were. Isolated samples 92 from of lungs and nasal discharges, and identified by serological and non-serololgical tests, the loss rates by the infection were also investigatyed, and the antimicrobial sensitivities of the isolates were determined. The results obtained were as fellows : 1. The loss rate by respiratory infection was 11.9% among 1,819 heads which raised and 41.7% among 518 heads which lost by diseases, and the rate increased annually. 2. The loss rate of rabbits in Spring (45.0%), Summer (45.5%) and Winter (53.5%) showed significantly higher (P < 0.01) than that in Autumn(29.1%). 3. The loss rate of Rex (56.3%) showed significantly higher (P<0.05) than New Zealand White (40.7%) and Californian (42.0% ). 4. P. multocida.(37.9%), B. brouchiseptica (16.0%), E. coli (10.6%) and so forth were isolated from 92 samples of lungs and nasal discharges. 5. Sixty fours trains of P. multocida were typed by serological or non-serological tests and their all serotypes were A type (62 strains) except 2 strains of untypable. 6. In antimicrobial sensitivity test for 64 isolates of P. multocida, all the strains tested were highly sensitive to chloramphenicol(95.3%), colistin (95.3%), gentamicin (92.2%), kanamycin (90.6%), neomycin (82.8%) and tetracycline (81.3%), but exhibited low sensitivity to streptomycin (26.6%), and all strains were resistant to lincomycin. 7 Twenty seven isolates of B. brouchiseptica showed higher sensitivity to cephalothin (100%), erythromycin (100% ), gentamicin (100%). trimethoprim+sulfamethoxazole (100%), chloramphenicol(88.9%), kanamycin(88.9%), neomycin (88.9%) and colistin (85.2%), but lower sensitivity to nitrofurantoin (18.5%), penicillin(18.5%). streptomycin(18.5%) and ampicillin (14.8%), and all strains were resistant to lincomycin.

• Infection and chemotherapy
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• v.50 no.4
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• pp.328-339
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• 2018

Background: Pneumococcal disease is a major cause of morbidity and mortality worldwide, especially in patients with comorbidities and advanced age. This study evaluated trends in epidemiology of adult pneumococcal disease in Crete, Greece, by identifying serotype distribution and antimicrobial resistance of consecutive Streptococcus pneumoniae strains isolated from adults during an 8-year time period (2009-2016) and the indirect effect of the infant pneumococcal higher-valent conjugate vaccines 10-valent pneumococcal conjugate vaccine (PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13). Materials and Methods: Antimicrobial susceptibility was performed by E-test and serotyping by Quellung reaction. Multidrug resistance (MDR) was defined as non-susceptibility to penicillin (PNSP) combined with resistance to ${\geq}2$ non-${\beta}$-lactam antimicrobials. Results: A total of 135 S. pneumoniae strains were isolated from adults during the study period. Twenty-one serotypes were identified with 17F, 15A, 3, 19A, and 11A, being the most common. The coverage rates of PCV10, and PCV13 were 17.8% and 37.8%, respectively. PCV13 serotypes decreased significantly from 68.4% in 2009 to 8.3% in 2016 (P = 0.002). The most important emerging non-PCV13 serotypes were 17F, 15A, and 11A, with 15A being strongly associated with antimicrobial resistance and MDR. Among all study isolates, penicillin-resistant and MDR strains represented 7.4% and 14.1%, respectively. Predominant PNSP serotypes were 19A (21.7%), 11A (17.4%), and 15A (17.4%). Erythromycin, clindamycin, tetracycline, trimethoprim-sulfamethoxazole, and levofloxacin resistant rates were 30.4%, 15.6%, 16.3%, 16.3%, and 1.5%, respectively. Conclusion: Although pneumococcal disease continues to be a health burden in adults in Crete, our study reveals a herd protection effect of the infant pneumococcal higher-valent conjugate vaccination. Surveillance of changes in serotype distribution and antimicrobial resistance among pneumococcal isolates are necessary to guide optimal prevention and treatment strategies.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.6
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• pp.912-917
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• 2021

We investigated the distribution, molecular characteristics, and antimicrobial resistance of Vibrio vulnificus isolated from seawater at Gadeok Island, the Republic of Korea between June to October. Interestingly no isolates were detected between December to February. The detection rate of V. vulnificus was high (80-100%) from July to September 2019 and from June to September 2020. This coincided with the relatively low salinity of the seawater, which ranged from 7.8-29.9 practical salinity units for that period. Additionally, V. vulnificus had a high detection rate at sampling stations near the Nakdong river. The detection rates of virulence genes, such as vvhA, viuB, and vcgC, among the isolates were 97.1%, 44.1%, and 57.4% in 2019 and 100%, 43.0%, and 50.0% in 2020, respectively. Notably, viuB and vcgC were detected in V. vulnificus isolated between June to October when water temperature was above 20℃. The antimicrobial susceptibility analysis of 80 isolates revealed that most of the strains were susceptible to most antimicrobial agents. However, some isolates showed intermediate resistance to cefepime (18.8%), cefoxitin (58.8%), and erythromycin (22.5%). Of note, 3.8% of the tested strains were resistant to cefoxitin. The minimum inhibitory concentration of highly cefoxitin-resistant strains was determined to be less than 32 ㎍/mL.

• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.432-440
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• 2023

Irrational and injudicious use of antibiotics, easy availability of them as over-the-counter drugs in economically developing countries, and unavailability of regulatory policies governing antimicrobial use in agriculture, animals, and humans, has led to the development of multi-drug resistance (MDR) bacteria. The use of medicinal plants can be considered as an alternative, with a consequent impact on microbial resistance. We tested extracts of Piper longum fruits as new natural products as agents for reversing the resistance to antibiotics. Six crude extracts of P. longum fruits were utilized against a clinical isolate of multidrug-resistant Staphylococcus aureus.The antibiotic susceptibility testing disc method was used in the antibiotic resistance reversal analysis. Apart from cefoxitin and erythromycin, all other antibiotics used (lincosamides [clindamycin], quinolones [levofloxacin and ciprofloxacin], and aminoglycosides [amikacin and gentamicin]) were enhanced by P. longum extracts. The extracts that showed the greatest synergy with the antibiotics were EAPL (ethyl acetate [extract of] P. longum), n-BPL (n-butanol [extract of] P. longum), and MPL (methanolic [extract of] P. longum The results of this study suggest that P. longum extracts have the ability to increase the effectiveness of different classes of antibiotics and reverse their resistance. However, future studies are needed to elucidate the molecular mechanisms behind the synergy between antibiotic and phytocompound(s) and identify the active biomolecules of P. longum responsible for the synergy in S. aureus.

• Korean Journal of Veterinary Service
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• v.47 no.1
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• pp.27-33
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• 2024

At the present study, it was aimed to explore the states of antimicrobial resistant Staphylococcus aureus isolates from 1,360 chickens, pigs and cattle carcass (400 chickens, 480 pigs and 480 cattle) in Daegu province from January 2022 to December 2022. Among 1,360 samples, 81 of S. aureus were isolated cattle (1.4%), pigs (7.7%) and chickens (9.2%). In antimicrobial susceptibility test, all of the isolates were demonstrated susceptibility to rifampin. But the isolates were showed resistance other antibiotics in order of tetracycline (62.9%), ciprofloxacin (62.9%), tobramycin (58.0%), gentamicin (51.8%), amikacin (40.7%), penicillin (39.5%), clindamycin (35.8%), enrofloxacin (33.3%), trimethoprim/sulfamethoxazole (30.8%), oxacillin (30.8%), minocycline (29.6%), erythromycin (25.9%), quinupristin/dalfopristin (20.9%), chloramphenicol (12.3%), cefoxitin (9.8%). Among the 81 S. aureus isolates, 25 (30.8%) methicillin-resistant staphylococcus aureus (MRSA) were observed. Seven (28.0%) of 25 MRSA harbored mecA gene. About 96% of MRSA were multidrug resistance to at least 3 more drugs. A continuous monitoring and surveillance program to prevent antimicrobial resistance in livestock products is demanded.

• 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 dental hygiene science
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• v.12 no.2
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• pp.109-113
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• 2012

One hundred seventy four Streptococcus pneumoniae clinical isolates were categorized depending on the types of specimens, the age and the gender, respectively. All isolates were analyzed the characteristics of the multi-drug resistance including levofloxacin antibiotics. In the results of analysis depending on the type of samples, it had been confirmed that sputum was the main source of pneumonia infection because 156 of 174 strains (89.7%) were isolated in sputum samples. The opportunity for isolating the S. pneumoniae that had tolerance to levofloxacin was increased in over 51 age patients group compared with other age and male group. Eight strains of isolates were evaluated higher resistant to levofloxacin, and those also showed multi-drug resistant including penicillin, tetracycline, erythromycin, clindamycin and trimethoprim-sulfamethoxazole. In the results of sequence analysis of quinolone resistance determining region in SP32 (MIC $64{\mu}g/mL$) and SP96 (MIC $8{\mu}g/mL$) which were levofloxacin resistant strains, an amino acid substitutions were found Ser-81$\rightarrow$Phe in both GyrA of SP32 and SP96, and Ser-11$\rightarrow$Gly in only SP96. A Ser-79$\rightarrow$Phe substitution of ParC was found in both.