• 한국습지학회지
• /
• 제13권1호
• /
• pp.117-127
• /
• 2011

본 연구의 목적은 하수처리장의 공간적 그리고 운전인자에 따른 테트라싸이클린 내성균(TRB) 및 테트라싸이클린 내성 유전자(TRG)들의 거동을 파악하는데 있다. 이를 위한 노력으로, 세 개의 실제 다른 하수처리장내에서 7개월 이상 각각의 반응조별로 시료를 채취하여 TRB 및 TRG가 분석되었다. 통계 기법은 주성분분석(PCA)을 통해 이들 간에 어떠한 일반적 관계식이 성립하는지 알아보려 노력하였다. 통계 분석결과, 활성슬러지내에 TRB 농도는 1차 침전 유입수에 있는 TRB 농도에 많은 영향을 받는 것을 알 수 있었다. 또한, 본 연구를 통해 TRB와 TRG의 내거동이 하수처리장 SRT 조건에 많이 영향을 받는 것을 알 수 있었다.

• International Journal of Oral Biology
• /
• 제40권1호
• /
• pp.41-50
• /
• 2015

The aim of this study was to identify bacteria isolated from the oral cavities and to determine their antimicrobial susceptibility against eight antibiotics. The bacterial strains were obtained from the Korean Collection for Oral Microbiology (KCOM). The bacteria were identified by comparing 16S rDNA sequences at the species level. The data showed that 77 bacterial strains were predominantly identified as streptococci (49.4%) and staphylococci (14.3%). Minimum inhibitory concentrations (MIC) were determined using a broth dilution assay to test the sensitivity of the bacterial strains. The MIC values of the oral bacterial strains against antibiotics were different. Streptococci were sensitive to clindamycin, cefuroxime axetil, and vancomycin, and they were resistant to tetracycline. Staphylococci also were sensitive to clindamycin, cefuroxime axetil, and vancomycin, and they were resistant to penicillin antibiotics. Gramnegative bacterial strains were sensitive to tetracycline and were resistant to clindamycin. These results suggest that the antimicrobial susceptibility test is necessary in deciding the prescription for antibiotics, to prevent the misuse or abuse of antibiotics.

• 대한수의학회지
• /
• 제59권4호
• /
• pp.207-211
• /
• 2019

Mass mortality in commercially cultured Amur catfish (Silurus asotus), showing symptoms of dermal ulcerations, occurred on a private farm in Mar 2019 in Korea. β-hemolytic bacteria were isolated from the ulcers and kidneys of the fish and identified as Aeromonas veronii. The isolate was resistant to tetracycline and possessed cytotoxic heat-labile enterotoxin (aerolysin/hemolysin). We investigated the genetic determinants associated with tetracycline resistance, and the isolate has been confirmed to simultaneously possess tetA and tetE genes. This is the first report on the occurrence of tetracycline-resistant A. veronii infection related to mass mortality in commercially cultured Amur catfish in Korea.

• 대한미생물학회지
• /
• 제15권1호
• /
• pp.19-32
• /
• 1980

Besides the benefits of antimicrobial agents in the control of various infectious diseases, widespread and prolonged use of particular antimicrobial agents has brought about the increase of drug-resistant strains in a community and the profound changes in the pattern of infectious diseases. In Korea, there are some remote villages where no clinics and drug stores are available and the residents in those areas are assumed to have fewer chances to contact with antimicrobial agents. In the present study, the differences in susceptibilities to 14 antimicrobial agents between the isolates from rural areas(R) and Seoul National University Hospital(SNUH, H) were studied. The isolates and their numbers were Staphylococcus aureus, R;55, H;68), Enterococci(R;28, H;30), Escherichia coli(R;40, H;40), Enterobacter aerogenes(R;25, H;21) and Klebsiella pneunoniae(R;58, H;67). Minimal inhibitory concentrations(MIC's) of penicillin, ampicillin, carbenicillin, cephalexin, tetracycline, oxytetracyline, doxycycline, minocycline, gentamicin, kanamycin, streptomycin, erythromycin, troleandomycin and co-trimoxazole were determined by agar dilution method. I. Comparison of MIC's and resistant strain proportions between isolates from SNUH and rural areas. MIC's and/or resistant strain proportions of the isolates from SNUH were significantly higher than those of the isolates from rural areas in the cases of 1. S. aureus to doxycycline, streptomycin and kanamycin. 2. E. coli to penicillin, ampicillin, carbenicillin, tetracycline, oxytetracycline, doxycycline, minocycline, streptomycin, kanamycin, erythromycin and co-trimoxazole. 3. E. aerogences to carbenicillin, tetracycline, oxytetracycline, doxycycline, minocycline, streptomycin, kanamycin, genaamicin and co-trimoxazole. 4. K pneunoniae to penicillin, ampicillin, tetracycline, oxytetracycline, doxycycline, monocycline, streptomycin, kanamycine, gentamicin and co-trimoxazole. However, the mean MIC and resistant strain proportion of S. aureus to tetracycline were higher in isolates from rural areas than in those from SNUH and Enterococci showed no differences in susceptibilities to the antimicrobial agents between isolates from rural areas and from SNUH. Therefore, in general, differenes in susceptibility to these antimicrobial agents between the isolates from rural areas and SNUH were remarkably greater and broader in gram negative enteric bacteria. II. Multiple drug resistance pattern. Patterns and incidences of multiple drug resistance were studied with penicillin, ampicillin, tetracycline, cephalexin, gentamicin, streptomcin, kanamycin and co-trimoxazole in Enterococci, E. coli, E. aeroges and K. pneumoniae. There appeared significant differences in the incidence of multiply drug-resistant strains and multiple drug resistance patterns between the isolates from SNUH and rural areas in Enterococci, E. coli, E. aerogenes and K. pneumoniae. However, there was no difference in the incidence of multiply drug-resistant strains between isolates of S. aureus from SNUH and rural areas but the pattern of multiple resistance of the SNUH strains of S. aureus was diverse, while that of the rural strains was predominantly confined to penicillin-tetracycline combination. The incidence of multigly drug-resistant strains and diversity of their patterns were the highest in E. coli strains isolated from SNUH and there were no multiply drug resistant strrains in Enterococci and K. pneumoniae strains isolated from rural areas. The number of drug-resistance determinants was also different between the isolates from rural areas and SNUH. Most of the multiply drug-resistant strains of E. coli, E. aerogenes and K. pneumoniae isolated from SNUH were resistant to more than 3 kinds of antimicrobial agents, most frequently to ampicillin, tetracycline and streptomycin, while multiply drug-resistant strains from rural areas were resistant to 2 kinds of antimicrobial agents among ampicillin, tetracycline and streptomycin. With drug-resistant E. coli strains, resistance to tetracycline which was used most widely since 1951 was most frequently involved as a part of mutliple drug-resistance, followed by resistance to ampicillin and streptomycin. This strongly suggests that emergence of drug-restant strains in a community is directly dependent on the selective pressure exerted by the antimicrobial agent used. III. Cross resistance. Cross resistance of bacteria was studied among tetracycline penicillin, aminoglycoside and macrolide derivatives by analyzing correlation coefficients of sucseptibilities using the least square method. In this study, there were high correlations among the susceptibilities to related derivatives. It appears that the relatively low correlations in susceptibilities present in some cases are due to intrinsic resistance of E. aerogenes to penicillin, Enterococci to aminoglycoside and E. coli E. aerogenes and K. pneumoniae to macrolide derivatives.

• 한국수산과학회지
• /
• 제45권3호
• /
• pp.238-245
• /
• 2012

In this study, the molecular structures of tet(M) and tet(G) carried by tetracycline (Tc) resistant bacteria in intestinal microflora from the imported ornamental fish were characterized and compared with each other depend on the imported countries. Of the total isolates, approximately 8.9% of the Ent-lac+(lactose fermentative bacteria on coliform media) Tc resistant isolates in fish from three different countries, Singapore, Taiwan and Brazil, were appeared to contain tet(M). Three representative isolates of different countries, Aeromonas spp. JSM-1 (Singapore), JTM-1 (Taiwan) and JBM-1 (Brazil), were isolated and analyzed the molecular structures of tet(M) gene. Interestingly, partial sequence of tet(M) genes (1099 bp) in JBM-1 (Brazil) showed 99.5% homology with the tet(M) found in the Vibrio spp. RV16 isolate, obtained from marine fish in Korea and known to carry Tn1545 parent type of tet(M). In contrast, tet(M) gene in JSM-1 and JTM-1 showed mosaic structure of Tn1545 and Tn916, and 100% homology with each other. It may suggest the presence of various characteristics in terms of tet(M) gene structure. The determined sequence of the tet(G) from Aeromonas spp. JSG-1 and JBG-1 isolated from Singapore and Indonesia ornamental fish respectively showed similar nucleotide sequence homology but revealed a few nucleotide changes in comparison with the sequence of the prototype tet(G) gene (S52437 in GenBank).

• Journal of Microbiology
• /
• 제45권1호
• /
• pp.64-68
• /
• 2007

In this study we examined the multi-drug resistance profiles of the tetracycline (TC) resistant genus Vibrio to determine its susceptibility to two ${\beta}-lactams$, ampicillin (ABPC), and mecillinam (MPC), as well as to macrolide, erythromycin (EM). The results showed various patterns of resistance among strains that were isolated from very close geographical areas during the same year, suggesting diverse patterns of drug resistance in environmental bacteria from this area. In addition, the cross-resistance patterns suggested that the resistance determinants among Vibrio spp. are acquired differently within the sediment and seawater environments.

• 상하수도학회지
• /
• 제35권1호
• /
• pp.27-37
• /
• 2021

Tetracycline is one of the most commonly used as antibiotics for the livestock industry and it is still widely used nowadays. Tetracycline and its metabolites are excreted with excrement, which is difficult to completely removed with conventional sewage treatment, therefore it is apprehended that the tetracycline-resistant bacteria occurs. In this study, the oxidant named ferrate(VI) was used to degrade the tetracycline and investigate the reaction between ferrate(VI) and tetracycline under various aqueous conditions. The highest degradation efficiency of tetracycline occurred in basic condition (pH 10.1 ± 0.1) because of the pKa values of tetracycline and ferrate(VI). The results also showed the effect of water temperature on the degradation of tetracycline was not significant. In addition, the dosage of ferrate(VI) was higher, the degradation of tetracycline and the self-degradation of ferrate(VI) also higher, finally the efficiency of ferrate(VI) was lower. The results said that the various mechanisms effects the reaction of ferrate(VI) oxidation, it required the consideration of the characteristics of the target compound for optimal degradation efficiency. Additionally, intermediate products were detected with LC/MS/MS and three degradation pathways were proposed.

• 한국가금학회지
• /
• 제7권1호
• /
• pp.53-64
• /
• 1980

A total of 1503 specimens were submitted to the Poultry Disease Diagnostic Service Laboratory during the year 1966 and 1978. The most frequently diagnosed diseases in order of prevalence were avian mycoplasmosis, staphylococcosis, colibacillosis, salmonellosis and pullorum disease, the percentages of the conditions being 24.6%, 20.0%, 18.0%, 12.6% and 6.4%, respectively, The drug resistance of pathogenic mirnoorganisms isolated during the year 1978 from chicken with colicabacillosis, staphylococcosis or salmonellosis were investigated by the use of disc diffusion technique, the results being as follow. 1) Drug resistance of 63 strains of Escherichia coli More than 95% of the strains tested were sensitive to colistin and gentamicin. The percentages of strains sensitive to kanamycin, chloramphenicol, ampicillin and nitrofurantoin were 66.7%, 60.3%, 60.3% and 47.6%, respectively. Majority of the strains were highly resistant to streptomycin and tetracyline. All the strains were resisistant to bacitracin lincomycin, oleandomycin, penicillin and erythromycin. All the strains tested were resistant to more than two among 10 drugs in common use such as penicillin, erythromycin, streptomycin, tetracycline, neomycin, chloramphenicol, kanamycin, ampicillin and gentamicin, and 27 different resistance patterns were noted. The most frequent multiple resistance pattern was PC, EM, SM and TC (11.1%). 2) Drug resistance of 48 strains of Salmonella More than 95% of the strains tested were sensitive to colistin, gentamicin ana ampicillin. The percentages of st rains sensitive to kanamycin, tetracycline, neomycin and nitrofurantoin were 81,3%, 79%, 72.9%, and 68.0% respectively. None of them was sensitive to streptomycin, oleandomycin, erythromycin, lincomycin and bacitracin. All the strains were resistant to more than one among 7 drugs in common use such as streptomycin, erythromycin, neomycin, tetracycline, kanamycin, ampicillin and gentamicin. The most frequent resistance pattern was SM and EM(66.7%). 3) Drug resistance of 54 strains of Staphylococci All the strains tested were sensitive to gentmaicin, kanamycin and cephalothin. Majority of them were highly sensitive to bacitracin, methicillin, nitrofurantoin and chloramphenicol. The Percentages of strains sensitive to streptomycin, ampicillin, lincomycin and tetracycline were 66.7%, 55.6%, 44.4% and 27.8%, respectively. Among them, 51 strains were resistant to more than one among 11 drugs in common use such as tetracycline, lincomycin, ampicillin, penicillin, streptomycin, erythromycin, neomycin, oleandomycin, chloramphenicol, methicillin and bacitracin, and thirty one different resistance patterns were noted.

• 한국어병학회지
• /
• 제34권1호
• /
• pp.39-46
• /
• 2021

Tetracycline (TC)은 국내에서 세균 감염 치료에 반드시 필요한 대표적인 항생제로 알려져 있다. 그러나 부적절한 사용과 남용으로 인해 Tetracycline, Erythromycin, Fluoroquinolone 등과 같은 항생제에 대한 내성이 발생하고 있으며, 이는 국내 양식 분야에서 심각한 경제적 피해를 유발한다. 본 연구에서는 2015~2018년에 걸쳐 경기도 양식장의 양식생물에서 101개 균주를 분리하였다. 분리균주는 간이적인 생화학적 방법을 통해 동정하였으며, 최소 억제농도(MIC)의 확인을 통해 Oxytetracycline (OTC), Ampicillin (AMP), Clindamycin (CLI), Enrofloxacin (ENRO), Gentamycin (GEN)에 대한 내성 여부를 확인하였다. 이중 TC에 내성을 보이는 균주는 PCR법을 통해 tet 유전자의 분포를 조사하였다. 그 결과, 총 101개 균주 중에서 Aeromonas spp.가 44개(43.5%)로 가장 우점하였고, 그 다음으로 Pseudomonas spp. 4개(4.0%), Vibrio spp. 5개(5.0%)가 확인되었다. 또한, 다중 내성을 보이는 균주(77.2%)가 단일 내성균(22.8%)보다 많음을 확인하였다. tet(A), tet(D), tet(E), tet(G), tet(M), tet(S)가 TC 내성 균주에서 검출되었으며 tet(A)가 가장 우점적으로 확인되었다. Aeromonas spp.는 분리된 균주 중에서 가장 많았으며, 경기도 내 양식현장에서의 다양한 항생제 내성 유전자의 특성에 대한 추가적인 연구가 필요하다.

• 한국미생물·생명공학회지
• /
• 제37권3호
• /
• pp.258-265
• /
• 2009

축산환경개선용 미생물 제품 중 시장점유율을 기준으로 상위제품 A, B,하위 제품 E, F와 현재 개발완료 되어진 C, D를 선정하여 생균수 측정과, 사료첨가용으로 사용이 금지된 항생제에 대한 내성 테스트를 실시하였다. 생균수 측정 결과 상위 점유율의 A, B사 제품은 표기상의 생균수와 일치하였으나, 하위 점유율을 차지하고 있는 E제품의 경우 함유균주나 효능에 대한 정보를 제공하고 않고 있을뿐더러 F사의 제품은 균수가 적게 측정되어 실제 표기사항과 일치하지 않았다. 항생제 내성실험결과 점유율에 따른 상관관계는 없었으나, B사를 제외한 제품의 대부분에서 내성균이 존재함을 확인하였다. Lincosimides 계열의 Lincomycicne과 Clindamycin의 경우 B사를 제외한 제품에서 내성균이 존재하였다. Penicillins 계열의 Amoxicillin, Ampicillin, Penicillin 및 Macrolide 계열의 Erythromycin 항생제는 B사와 E를 제외한 제품에서 내성균이 존재함을 확인하였다. Quinoline계열 Norploxacin 또한 B사와 E사를 제외한 제품에서 내성균을 보였으며 Neomycin의 항생제 또한 유사한 내성분포 결과를 나타내었다. Neomycin과 같은 Aminiglycosides계열의 Gentamycin, Streptomycin은 B사제품을 제외한 제품에서 내성을 나타내었다. 마지막으로 내성-균으로 사용 금지된 Tetracycline계열의 Oxytetracyclin은 12가지 항생제중 가장 높은 비율의 감수성을 나타내었으나 B, E사를 제외한 제품에서 내성균의 존재를 확인하였다. 실험결과 사용 금지된 항생제 품목임에도 불구하고 많은 제품에서 때 성균이 존재하였으며, 이에 따라 환경개선제 특성의 정확한 표기와 체계적인 유통 체계와 검증 과정이 필요하다고 사료된다.