• Journal of fish pathology
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• v.34 no.1
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• pp.39-46
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• 2021

Tetracycline (TC) is one of the antibiotics used for treatment of bacterial infection in Korea. Inadequate usage and abuse cause the resistance to antibiotics, like Tetracycline, Erythromycin, and Fluoroquinolone. It can also affect severe economic loss in aquaculture field in Korea. We isolated 101 bacterial samples from diseased fish at aquaculture sites in Gyeonggi-do during 2015~2018. Minimum inhibitory concentration (MIC) method has been used to determine distribution and to identify bacterial isolates resistant to antibiotics including Oxytetracycline (OTC), Ampicillin (AMP), Clindamycin (CLI), Enrofloxacin (ENRO), Gentamycin (GEN). TC resistant isolates were confirmed antibiotic resistant genes by conventional PCR. Bacterial isolates were identified as Aeromonas spp. (43.5%), Pseudomonas spp. (4.0%) and Vibrio spp. (5.0%). It was confirmed that multi-resistant isolates (77.2%) were predominant over single-resistant one (22.8%). TC resistant genes like tet(A), tet(D), tet(E), tet(G), tet(M), and tet(S) were detected and tet(A) was the most prevalent. Aeromonas spp. is a dominant strain in bacterial infections in fishes of aquaculture sites, and further investigation on various antibiotic resistance genes will be needed for clear understanding of aquaculture sites in Gyeonggi-do.

• Microbiology and Biotechnology Letters
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• v.43 no.4
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• pp.396-400
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• 2015

Enterobacteriaceae is one of the major families responsible for public health threats. Due to the emergence of pathogens with antibiotic resistance, great concern has been raised regarding the prevalence of antibiotic resistant bacteria in natural environments. Therefore, the diversity of Gram negative Enterobacteriaceae was investigated in water samples collected from five streams in Korea using the cultivation method. Profiling of multi-drug resistance was conducted with isolates via disk diffusion assay. The results indicated that the Gram negative Enterobacteriaceae consisted of the following genus; Citrobacter, Enterobacter, Escherichia, Klebsiella, Kluyvera, Pantoea, Plesiomonas, Raoultella, Shigella and Enterobacter. These latter strains represented 49% of identified isolates. In addition, 78.3% of the identified genus exhibited resistance against more than seven out of thirteen tested antibiotics, suggesting a high prevalence of multi-drug resistant bacteria in natural environments.

• Journal of Environmental Health Sciences
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• v.41 no.1
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• pp.40-48
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• 2015

Objectives: This study aims to understand the concentration, diversity, and antibiotic characteristics of oxytetracycline resistant bacteria present in a surface water environment. Methods: Water sampling was performed in Cheongmi Stream in Gyeonggi-do, Korea in February and August 2014. Water samples collected from two sites were plated in triplicate on tryptic soy agar plates with 30 mg/L of oxytetracycline. Oxytetracycline resistant bacteria were selected from surface water in Cheongmi Stream and were subjected to 16S rDNA analysis for oxytetracycline resistant species determination. Identified resistant strains were tested for resistance to various antibiotics. Results: Results from this study indicate that the dominant resistant organisms in this aquatic environment are from family Acinetobacter and family Aeromonas. As to culturable heterotrophic bacteria, Oxytetracycline resistant bacteria were present 0.45-0.93% during winter and 0.08-0.38% during summer. Most oxytetracycline resistant bacteria exhibited resistance to more than ten of the antibiotics studied. The diversity of oxytetracycline resistant bacteria in winter was higher than in summer. Conclusion: Most of these resistant bacteria are Gram negative and are closely related to pathogenic species. These results suggest that increasing multi-antibiotic resistant bacteria in the surface water environment has a close relation to the reckless use of antibiotics in livestock.

• Korean Journal of Clinical Laboratory Science
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• v.36 no.2
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• pp.89-97
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• 2004

Many strains of Staphylococcus aureus were isolated from pus samples from primary, secondary, and tertiary medical institutions and were subjected to an antibiotic sensitivity test. Ciprofloxacin, clindamycin, erythromycin, gentamicin, oxacillin penicillin, tetracycline, trimethoprim/sulfamethoxazole, vancomycin and teicoplanin were used for the antibiotic sensitivity test. The strains showed hightest resistance to penicillin(91%), but all of strains tested were susceptible to vancomycin and teicoplanin. The isolated multi-drug(penicillin-tetracycline-ciprofloxacin-clindamycin-erythromycin- oxacillin-gentamicin) resistant S. aureus were analyzed genotypically using an AP-PCR(Arbitrarily Primed polymerase chain reaction) with an arbitrary 3 primers. Based on the result for genotype analysis, the genotypes identified by S1 primer did not coincide with those of S2 or E2 primers. Genotypes identified by S2 primer did not coincide with those of S1 or E2 primers. Also genotypes identified by the E2 primer did not coincide with those of S1 or S2 primers. Therefore, an analysis of AP-PCR test with multiple primers will provide more sensitive identification. A strain from a secondary medical institution and a strain from a tertiary medical institution which showed the same genotype for S1, S2, and E2 primers are required for further epidemiological study.

• Korean Journal of Pharmacognosy
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• v.39 no.4
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• pp.369-380
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• 2008

The essential oils from 73 aromatic herb drugs entered on Korean official formularies were tested for antibioticresistance inhibitory effect. When the oils were combined with ampicillin (Am) or amoxicillin (Amx) they showed significant inhibitory effects on the growth of multi-drug resistant Staphylococcus aureus SA2 in considerably low concentration. The most effective combination were oils from Magnoliae Flos or Piperis longi Fructus ($25{\mu}g/mL$)-Am or Amx ($4{\mu}g/mL$).

• Biomedical Science Letters
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• v.19 no.3
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• pp.280-283
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• 2013

Leuconostoc spp. is intrinsically resistant against vancomycin and rarely causes the infection in immunocompromised patients. In this report, we describe a fatal case of Leuconostoc lactis bacteremia in a patient with biliary tract stent insertion to resolve the biliary tract obstruction by multiple pseudocysts in the pancreatic head region. Leuconostic lactis isolated from the blood of the patients was confirmed by 16S rRNA sequencing and this isolate was susceptible against most antibiotics, including levofloxacin, penicillin, erythromycin and cefotaxime except vancomycin. The septic shock and multi-organ failure was abruptly progressed due to delayed use of adequate antibiotic. Using vancomycin as the empirical antibiotics in a bacteremic patient by Gram positive cocci, the treatment failures by the isolates with intrinsic resistance against vancomycin have to be considered. In addition, the prompt and accurate identification of Leuconostoc spp. are very important to select the adequate antibiotics.

• Journal of Veterinary Clinics
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• v.25 no.4
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• pp.231-235
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• 2008

Various kinds of antibiotic intramammary infusions are used for treatment of bovine mastitis. As antibiotic-resistant bacteria are increased, the therapeutic rate for bovine mastitis is decreased. The goal of this research is to detect significant synergic effects of combination of antibiotics with sulbactam, $\beta$-lactamase inhibitor, on methicilin-resistant Staphylococcus aureus (MRSA). We used 5 strains of MRSA isolated from bovine mastitis with clinical and subclinical signs. All of the bacteria isolated had resistance to oxacillin and showed multi-resistant patterns in the antimicrobial susceptibility tests. Minimal bactericidal concentrations of ampicillin, amoxicillin, cephalexin, ampicillin/sulbactam(2:1), amoxicillin/sulbactam (2:1), and cephalexin/sulbactam (1:1) were measured according to broth microdilution method suggested by National Committee for Clinical Laboratory Standards (NCCLS, M31-A2) to compare the synergic effects of sulbactam combination with each antibiotic alone. Ampicillin and amoxicillin showed synergic antibacterial activity to 4 and 3 respectively in 5 strains of MRSA in combination with sulbactam. This study demonstrates that ampicillin/sulbactam and amoxicillin/sulbactam can be therapeutic choices for mastitis associated with MRSA.

• Korean Journal of Veterinary Service
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• v.39 no.3
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• pp.175-181
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• 2016

Staphylococcus pseudintermedius is an important opportunistic pathogen of dog and cats. Since 2006 there has been a significant emergence of methicillin-resistant S. pseudintermedius (MRSP) mainly due to clonal spread. The aim of this study was to investigated the prevalence of antibiotic resistance and presence of mecA and femA gene in 91 S. pseudintermedius isolates isolated from dogs and cats associated with various clinic infections. Methicillin resistance was confirmed by oxacillin disc diffusion method. MRSP isolate was detected 19 isolates (20.9%). MRSP and methicillin-resistant S. pseudintermedius (MSSP) isolates were highly resistant to penicillin, kanamycin, tetracycline, erythromycin, trimethoprim-sulfamethoxazole, clindamycin, ciprofloxacin, enrofloxacin and choloramphenicol (100~47.3% and 90.3~33.3%, respectively). About 90% of MRSP isolates were multi-drug resistance (resistance to at least five or more antimicrobials), and MSSP isolates was ca 74%. Among the 91 isolates, mecA gene was detected in 25 isolates (27.5%, 19 in MRSP isolates and 6 in MSSP isolates), but none carried the femA gene. Our results indicated MRSA isolates show a strong resistance to antimicrobials commonly used in veterinary medicine. A continuous surveillance and monitoring should be called for to prevent the contamination and spread of MRSP in dogs and cats.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.135-140
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• 2017

The aim of this study was to investigate the distribution of genes that encode multi-drug efflux pumps and virulence factors in Enterococcus faecalis isolated from retail meat and antibiotic resistance patterns of these strains. Of the 277 retail meat samples, 93 Enterococcus faecalis were isolated. The strains exhibited resistance to ampicillin (35.5%), chloramphenicol (6.4%), ciprofloxacin (4.3%), erythromycin (18.3%), levofloxacin (0%), quinupristin-dalfopristin (76.3%), tetracycline (45.2%), teicoplanin (0%) and vancomycin (0%). The strains were positive for MFS type eme(A) (100%), ABC type efr(A) (100%), ABC type efr(B) (98.9%) and ABC type lsa (91.4%) efflux pump gene. The strains were positive for gelE (68.8%), ace (90.3%), asa1 (47.3%), efaA (91.4%) and esp (12.9%) virulence gene. This research will help to assess the hazards associated with the occurrence of drug resistance among enterococci from retail meat. Therefore, it is necessary to monitor enterococcus spp. isolated from retail meat continuously.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.413-419
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• 2021

The purpose of this study was to investigate the ability to treat and prevent infection by multiple Gram-negative bacterial pathogens as a last choice option in the treatment of serious infections in clinical settings. The global spread of extended-spectrum 𝛽-lactamases (ESBLs) and/or carbapenemases in microorganisms are of enormous concern to health services because they are often associated with multi-drug resistance which significantly restricts the antibiotic treatment options. In this study, the antimicrobial resistance profiles of bacteria isolated from South Korean market-derived meat samples were determined by the disc diffusion method. PCR was used to detect the presence of antibiotic resistance genes and ESBL producing genes. In total, we tested 181 isolated colonies from 36 market-derived meat samples. Single PCR and DNA sequencing results revealed that genes blaVIM, blaBIC, blaKPC, and blaSIM were present in the bacteria isolated from retail meat. The bacteria in the meat were separately sequenced and based on alignment, four different bacteria were identified. These findings suggest that bacteria found in retail meats are a reservoir for the spreading of ESBL blaVIM, blaBIC, blaKPC, and blaSIM resistance genes and bacteria strains.