• Natural Product Sciences
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• v.17 no.4
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• pp.296-302
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• 2011

We determined the inhibitory activity of the essential oil fraction obtained by steam distillation from the fresh and dried leaves of Perilla frutescens var. acuta against some pathogenic Salmonella and Vibrio spp. The activities of compounds isolated from the essential oils, apiol and myristicin, were also tested and the results were compared with those of the essential oil fraction. The Perilla essential oil fraction and its main components showed significant inhibition against antibiotic-susceptive and antibiotic-resistant strains of the tested Salmonella and Vibrio strains. Synergistic or additive effects were identified by combing the oils with ampicillin by checkerboard-titer tests. We conclude that essential oils from P. frutescens can be useful in the treatment of Salmonella and Vibrio infections and as safe additives to food materials for the prevention of contamination of food by these bacteria. This is especially important because of the rapid increase in antibiotic-resistant strains, which could cause severe symptoms in humans.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.5
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• pp.626-633
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• 2023

Vibrio spp. are aquatic bacteria that are ubiquitous in warm estuarine and marine environments. Especially, V. vulnificus and V. cholerae are currently known to cause potentially fatal infections in humans. This study investigated the distribution and antibiotic resistance of V. vulnificus and V. cholerae isolated from coastal areas of Gyeongsangnam-do in 2022. A total of 252 samples of water, shellfish and coastal sediment were collected from 7 locations along the coast, and 124 samples of fishery products were collected from markets. Among the 252 samples, forty-four V. vulnificus (11.7%) and fourteen V. cholerae non-O1/non-O139 (3.7%), none of which carried the ctx gene, were isolated. Out of the 124 samples, 6 (4.8%) tested positive for V. vulnificus and V. cholerae was not detected. The isolation rates of V. vulnificus and V. cholerae showed a significant correlation with environmental factors such as seawater temperature and salinity. In an antibiotic resistance test, V. vulnificus was susceptible to amikacin, gentamicin, imipenem trimethoprim/sulfamethoxazole, and ciprofloxacin, but resistant to cefoxitin (100.0%), followed by tetracycline (9.1%). Multidrug resistance was also observed. Continuous monitoring of Vibrio pathogens with water temperature and salinity is expected to help reduce the outbreaks, and rational use of antibiotic agents is needed to prevent the accession of antibiotic-resistant microorganisms in aquatic ecosystems.

• Journal of Practical Agriculture & Fisheries Research
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• v.22 no.2
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• pp.51-58
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• 2020

Continuous mortality in commercially cultured Japanese eel (Anguilla japonica), showing symptoms of dermal ulcerations and focal hemorrhages on the body, occurred on a private farm in November, 2019 in Korea. A series of mortality had been described in one local eel culture farm from November to December in 2019. From the three cases, three isolates of Vibrio spp. were recovered from the blood, ascitic fluid, and kidney of the dead fish, respectively. Based on the 16S rRNA sequence comparisons, the Vibrio isolates from the 1^st and 3^rd cases (strain named 1E1-2 and 3K1-2) were identified as V. fluvialis and the isolate from the 2^nd case was identified as V. plantisponsor (strain named 2A3-1). Moreover, the 16S rRNA-based phylogenetic analysis revealed that strain 1E1-2 and 3K1-2 were most similar to V. fluvialis NBRC 103150^T, and strain 2A3-1 was most similar to V. plantisponsor NBRC103148^T. According to the results of the antibiotic resistance determination, V. fluvialis 1E1-2 showed intermediate resistance to tetracycline and chloramphenicol, and was resistant to trimethoprim-sulfamethoxazole. V. plantisponsor 2A3-1 showed intermediate resistance to ciprofloxacin and levofloxacin, and was resistant to trimethoprim-sulfamethoxazole. V. fluvialis 3K1-2 showed intermediate resistance to tetracycline, and was resistant to ampicillin and trimethoprim-sulfamethoxazole. These results have provided the evidences on the occurrence of antibiotic-resistant Vibrio infection in commercially cultured Japanese eels are present in Korea.

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

• YAKHAK HOEJI
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• v.56 no.5
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• pp.320-325
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• 2012

To develop a new effective and safe natural antibiotics and antioxidant the essential oil was extracted from the roots of Anthriscus sylvestris by steam distillation. Its composition was analyzed by GC-MS. The activities of the essential oil fraction and its main components were evaluated against antibiotic-susceptible and -resistant strains of some food-born bacteria. In addition the synergism was examined with this oil combined with antibiotic by checkerboard titer test. The antioxidant activities were determined by in 1,1-diphenyl-2-picryl-hydrazil (DPPH) free radical scavenging activity test and reducing power assay. The essential oil fraction of A. sylvestris revealed significant inhibiting activities against antibiotic-susceptible and -resistant species of Vibrio and Shigella with MICs ranged from 1.00~4.00 mg/ml. It showed synergistic or additive effects when it was combined with amphicillin or trimethoprim/sulfamethoxazole (1 : 9). Additionally, the essential oil fraction of A. sylvestris exhibited significant DPPH free radical scavenging activity and the reducing power.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.637-641
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• 2010

The antibiotics-resistance profiles of 28 strains of Vibrio parahaemolyticus isolated from seawater were investigated. All of the strains studied were resistant to ampicillin (100%), but susceptible to 12 other antibiotics. The minimum inhibitory concentration (MIC) of V. parahaemolyticus to ampicillin was as high as $1,024-2,048\;{\mu}g{\cdot}mL^{-1}$. The phenotype of strain 8 changed from ampicillin-resistant to susceptible with an in-frame deletion mutant of VPA0477, a putative ${\beta}$-lactamase gene, and the MIC for ampicillin of the mutant strain was $1{\mu}g{\cdot}mL^{-1}$. In conclusion, our findings suggest that the VPA0477 gene acts as a ${\beta}$-lactamase in ampicillin-resistant V. parahaemolyticus strains.

• Korean Journal of Microbiology
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• v.54 no.1
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• pp.53-59
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• 2018

The objective of this study was to investigate the plasmid profiling of multi-drug resistant (MDR) Vibrio in influent (inflow) and effluent (discharged) water samples of fish farms in Jeju, South Korea. MDR isolates identified through disc diffusion susceptibility tests, were subjected to plasmid profiling. One hundred fifty Vibrio isolates were obtained from each influent and effluent water sample. All MDR isolates were subjected to plasmid profiling. Greater number of bacteria were enumerated from effluents (61%) comparing to influents (39%). High incidence of neomycin, sulfamethoxazole, amoxicillin and oxytetracycline resistance was observed among the isolates, which was higher in effluent samples. In contrast, Vibrio isolates were more susceptible to florfenicol, chloramphenicol, ciprofloxacin, and nalidixic acid. Among 99 (influent 39 and effluent 60) MDR isolates, a total of 58 (influent 38 and effluent 20) were found to bear plasmids ranging from 1.7 kb to >10 kb and showed 19 different antibiograms according to the size of plasmids. MDR isolates showed six and four distinct plasmid profiles in influent and effluent, respectively. Effluent samples contained more plasmid-carrying MDR Vibrio isolates with more diverse plasmid profiles and antibiograms, suggesting that fish farm tanks may serve as a reservoir of antibiotic resistance genes. The presence of plasmid-carrying MDR Vibrio isolates in fish farm effluent water may contribute to the dissemination of antibiotic resistance genes to the environments, which ultimately poses threat to human health.

• Microbiology and Biotechnology Letters
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• v.40 no.3
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• pp.197-207
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• 2012

This study investigated the role of plasmids and their relationship with the multiple antibiotic resistance of 30 Vibrios sp. isolated from molluscs and crustaceans sampled from the Kerala coastal waters of India. The biochemical identification and antibiotic resistance profiles were determined, followed by the plasmid profiles, conjugation and transformation efficiencies. The results showed a considerable difference in the level of bacterial resistance to various antibiotics; while all 30 strains were found to be MAR Vibrios sp. and their resistance patterns varied. All the strains were resistant to amoxycillin, ampicillin and carbeniciliin. 87% were resistant to rifampicin; 74% to cefuroxime; 67 to streptomycin; 53% to norfloxacin and ciprofloxacin and 47% to furazolidone and nalidixic acid. In addition to their antibiotic resistance, the plasmid DNA of the MAR Vibrios strains isolated from the molluscs and crustaceans was also studied. Nine strains isolated from crustaceans and molluscs were found to harbor 1-3 plasmids with sizes varying from 5. 98 kb to 19. 36 kb. The average transformation efficiency was about $5{\times}10^{-8}$ and the conjugation efficiency varied from $2.1{\times}10^{-3}$ to $10^{-9}$. A further study of antibiotic resistance patterns may be useful to test the extent of drug resistance in seafoods and help to devise a nationwide antibiotic policy.

• Fisheries and Aquatic Sciences
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• v.12 no.1
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• pp.24-28
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• 2009

A tetracycline resistant Vibrio parahaemolyticus, capable of growing on TCBS medium containing tetracycline, was isolated from cultivated fishes. A gene responsible for the tetracycline resistance was cloned from chromosomal DNA of the V. parahaemolyticus strain using Escherichia coli KAM3, which lacks major multi-drug efflux pumps (${\Delta}acrB$) as host cells. The nucleotide sequence and homology analysis revealed an open reading frame (ORF) for tetracycline resistance protein (TetB). In order to characterize the antibiotic resistance of TetB originated from the V. parahaemolyticus strain, the gene was sub cloned into plasmid pSTV28. The resulting plasmid was designated as pSTVTetB and transformated into E. coli KAM3. E. coli KAM3 cells harboring the recombinant plasmid pSTVTetB are able to grow on plates containing tetracycline and oxytetracycline but not doxycycline, indicating that the tetB gene confers the tetracycline- and oxytetracycline-resistance to the host cell.

• Food Science and Biotechnology
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• v.14 no.2
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• pp.216-222
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• 2005

This study was performed to determine the antibiotic susceptibility profiles of Salmonella spp., coliforms, Listeria monocytogenes, Staphylococcus aureus and Vibrio spp. isolated from broiler carcasses, aquacultured flounders, hamburgers, and lettuce, which are foods consumed in large quantities in Korea. Salmonella spp. and L. monocytogenes were isolated only from broiler carcasses and Salmonella spp. had a high multidrug resistance rate of 61.1%. Meanwhile, coliforms and S. aureus were isolated from all four foods tested in this experiment. The multidrug resistance rate of coliforms from broiler carcasses was 50%, and that of Vibrio spp. from flounders was 71.4%. The resistance to tetracycline, streptomycin, ampicillin or carbenicillin was common regardless of the kind of food or isolate.