• 한국환경농학회지
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• 제20권5호
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• pp.330-334
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• 2001

The polymorphism of Azospirillum isolates from ornamental rhizosphere and two reference strains were examined with respect to intrinsic antibiotic resistance (IAR) profile. All the isolates showed different intrinsic resistances to different antibiotics viz., tetracycline, kanamycin, nalidixic acid, streptomycin, ampicillin, spectinomycin and chloramphenicol. All the strains demonstrated susceptibility to high concentration of all antibiotics used in the present experiment. In addition to these general patterns, we also obseved the multiple antibiotic resistances of Azospirillum strains. The Azospirillum sp. OAD-11 was resistant to tetracycline, streptomycin and ampicillin, and Azospirillum sp. OAD-57 was resistant to tetracycline and streptomycin. Conversely, Azospirillum sp. OAD-9 possessed the dual susceptibility to tetracycline and spectinomycin, whereas Azospirillum sp. OAD-37 was dual susceptible to streptomycin and kanamycin. Such multiple antibiotic resistant/susceptible traits could be useful for the identification of the strains in field experiments or in molecular genetic transfer experiments.

• 한국토양비료학회지
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• 제29권1호
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• pp.60-66
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• 1996

콩 근류균(根瘤菌) B. japonicum의 취락형태(聚落形態)에 따라 항생제반응(抗生劑反應)과 혈청형(血淸型) 및 단백질(蛋白質) 전기영동(電氣泳動) 유형(類型)에 차이가 있을지 여부를 구명(究明)코자 우리나라 남부지방에 분포한 토착근류균(土着根瘤菌)을 대상으로 시험한 결과는 다음과 같았다. 1. 분리(分離)한 B. japonicum 120균주(菌株) 취락형태별(聚落形態別) 분포(分布)는 "Dry"형이 47%, "Wet"형이 41%, "Dry/Wet"형이 12%였다. 2. 항생제(抗生劑) 반응(反應)에 있어서 "Dry"형의 균주(菌株)는 chlorampenicole(200ug/ml)과 kanamycin(20ug/ml)에 대하여. "Wet"형은 erythromycin(100ug/ml)과 nalidixic acid(20ug/ml), spectinomycin sulphate(100ug/ml), streptomycin sulphate(10ug/ml), tetracycline(100ug/ml)에 대하여 각각(各各) 높은 내성(耐性)을 보였다. 3. B. japonicum의 취락형태별(聚落形態別)로는 혈청형(血淸型)의 구분(區分)을 보이지 않았으나, 각 혈청형(血淸型)에 속하는 균주중(菌株中)에는 혈청모균주(血淸母菌株)와 동일한 취락형태(聚落形態)를 가진 것이 많았다. 4. B. japonicum의 혈청학적(血淸學的) 분류결과(分類結果)는 단백질전기영동상(蛋白質電氣泳動上)의 밴드유형과 같았으며 특히, 복잡성(複雜性)에 있어서는 가장 복잡하였던 항생제반응(抗生劑反應) 유형(類型)과 지나치게 단순하였던 취락형태적(聚落形態的) 구분이 중간정도(中間程度)를 나타내어 실용성(實用性)을 보였다. 5. B. japonicum의 취락형태별(聚落形態別) 특성은 항생제반응(抗生劑反應)에서는 특이적(特異的)이었으나 혈청학적(血淸學的) 특성(特性) 및 단백질(蛋白質) 전기영동(電氣泳動) 유형(類型)에서는 다양(多樣)한 경향이었다.

• 대한의생명과학회지
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• 제19권3호
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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.

• Mycobiology
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• 제32권4호
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• pp.173-178
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• 2004

Fifteen Rhizobium spp. from nodules of 6 common pulses collected from 6 districts of Assam were studied for their infectivity, intrinsic antibiotic resistance, nitrogenase activity and effect of dual inoculation with two native Arbuscular Mycorrhizal Fungi viz. Glomus mosseae(GM) and Gigaspora gilmarie(GG). Out of the 15 isolates 9 were found nodulation positive and 6 of them(AR1, BR8, BR12, AR10, UR10 & GR21) were subjected to intrinsic antibiotic sensitivity test of which AR1 showed resistance against all the 9 test antibiotics. Isolates AR1 and GR21 showed the highest(4.25 mole, $gm^{-1}hour^{-1}$) and the lowest(1.05 mole, $gm^{-1}hour^{-1}$) nitrogenase activity respectively. In Most Probable Number count, the maximum Rhizobium population $5.8{\times}10^5$, was found in both Blackgram and Greengram variety of pulses. The maximum dry weight of nodules(3.14 g), dry weight of shoot(10.08 g), nitrogen content(7.68 mg, $plant^{-1}$), chlorophyll content(1.89 mg, $g^{-1}$), phosphorus content of shoot(6.17 mg, $g^{-1}$) and yield(535.67 kg, $Ha^{-1}$) were found when AR1 dually inoculated with GM in Blackgram.

• Journal of Microbiology and Biotechnology
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• 제31권7호
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• pp.949-955
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• 2021

Previously, our research group isolated Bifidobacterium breve IDCC4401 from infant feces as a potential probiotic. For this study, we evaluated the safety of B. breve IDCC4401 using genomic and phenotypic analyses. Whole genome sequencing was performed to identify genomic characteristics and investigate the potential presence of genes encoding virulence, antibiotic resistance, and mobile genetic elements. Phenotypic analyses including antibiotic susceptibility, enzyme activity, production of biogenic amines (BAs), and proportion of D-/L-lactate were evaluated using E-test, API ZYM test, high-performance liquid chromatography (HPLC), and D-/L-lactic acid assay respectively. The genome of B. breve IDCC4401 consists of 2,426,499 bp with a GC content of 58.70% and 2,016 coding regions. Confirmation of the genome as B. breve was provided by its 98.93% similarity with B. breve DSM20213. Furthermore, B. breve IDCC4401 genes encoding virulence and antibiotic resistance were not identified. Although B. breve IDCC4401 showed antibiotic resistance against vancomycin, we confirmed that this was an intrinsic feature since the antibiotic resistance gene was not present. B. breve IDCC4401 showed leucine arylamidase, cystine arylamidase, α-galactosidase, β-galactosidase, and α-glucosidase activities, whereas it did not show production of harmful enzymes such as β-glucosidase and β-glucuronidase. In addition, B. breve IDCC4401 did not produce any tyramine, histamine, putrescine, cadaverine, or 2-phenethylamine, which are frequently detected BAs during fermentation. B. breve IDCC4401 produced 95.08% of L-lactate and 4.92% of D-lactate. Therefore, our findings demonstrate the safety of B. breve IDCC 4401 as a potential probiotic for use in the food industry.

• 대한약침학회지
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• 제22권1호
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• pp.49-54
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• 2019

Objective: Antibiotic resistance is a global health problem and threatens health of societies. These problems have led to a search for alternative approaches such as combination therapy. The aim of the present study was to investigate the effect of caffeine and omeprazole in combination with gentamicin or ciprofloxacin against standard and clinically resistant isolates of Staphylococcus aureus and Escherichia coli. Methods: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of different agents against bacterial strains were determined. The interaction of non- antibiotic drugs with gentamicin and ciprofloxacin was studied in vitro using a checkerboard method and calculating fraction inhibitory concentration index (FICI). Verapamil as efflux pump inhibitor was used to evaluate the possible mechanism of bacterial resistance to antibiotics. Results: The MIC and MBC values of gentamicin against bacterial strains were in the range of $20-80{\mu}g/ml$ and $40-200{\mu}g/ml$, respectively. Caffeine and omeprazole had no intrinsic inhibitory activity against tested microorganisms. However, upon combination of caffeine with antibiotics, the synergistic effects were observed. Verapamil was able to reduce the MIC values of gentamicin (4 folds) only in some bacterial strains. Conclusion: These findings indicated that caffeine was effective in removing bacterial infection caused by S. aureus and E. coli. The relevant mechanisms of antibiotic resistance were not related to the drug efflux.

• Fisheries and Aquatic Sciences
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• 제21권2호
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• pp.6.1-6.10
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• 2018

The intention of this study was to identify the bacterial pathogens infecting Oreochromis niloticus (Nile tilapia) and Clarias gariepinus (African catfish), and to establish the antibiotic susceptibility of fish bacteria in Uganda. A total of 288 fish samples from 40 fish farms (ponds, cages, and tanks) and 8 wild water sites were aseptically collected and bacteria isolated from the head kidney, liver, brain and spleen. The isolates were identified by their morphological characteristics, conventional biochemical tests and Analytical Profile Index test kits. Antibiotic susceptibility of selected bacteria was determined by the Kirby-Bauer disc diffusion method. The following well-known fish pathogens were identified at a farm prevalence of; Aeromonas hydrophila (43.8%), Aeromonas sobria (20.8%), Edwardsiella tarda (8.3%), Flavobacterium spp. (4.2%) and Streptococcus spp. (6.3%). Other bacteria with varying significance as fish pathogens were also identified including Plesiomonas shigelloides (25.0%), Chryseobacterium indoligenes (12.5%), Pseudomonas fluorescens (10.4%), Pseudomonas aeruginosa (4.2%), Pseudomonas stutzeri (2.1%), Vibrio cholerae (10.4%), Proteus spp. (6.3%), Citrobacter spp. (4.2%), Klebsiella spp. (4.2%) Serratia marcescens (4.2%), Burkholderia cepacia (2.1%), Comamonas testosteroni (8.3%) and Ralstonia picketti (2.1%). Aeromonas spp., Edwardsiella tarda and Streptococcus spp. were commonly isolated from diseased fish. Aeromonas spp. (n = 82) and Plesiomonas shigelloides (n = 73) were evaluated for antibiotic susceptibility. All isolates tested were susceptible to at-least ten (10) of the fourteen antibiotics evaluated. High levels of resistance were however expressed by all isolates to penicillin, oxacillin and ampicillin. This observed resistance is most probably intrinsic to those bacteria, suggesting minimal levels of acquired antibiotic resistance in fish bacteria from the study area. To our knowledge, this is the first study to establish the occurrence of several bacteria species infecting fish; and to determine antibiotic susceptibility of fish bacteria in Uganda. The current study provides baseline information for future reference and fish disease management in the country.

• Journal of Microbiology and Biotechnology
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• 제34권6호
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• pp.1276-1286
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• 2024

The environment has been identified as an origin, reservoir, and transmission route of antibiotic resistance genes (ARGs). Among diverse environments, freshwater environments have been recognized as pivotal in the transmission of ARGs between opportunistic pathogens and autochthonous bacteria such as Aeromonas spp. In this study, five environmental strains of Aeromonas spp. exhibiting multidrug resistance (MDR) were selected for whole-genome sequencing to ascertain their taxonomic assignment at the species-level and to delineate their ARG repertoires. Analyses of their genomes revealed the presence of one protein almost identical to AhQnr (A. hydrophila Qnr protein) and four novel proteins similar to AhQnr. To scrutinize the classification and taxonomic distribution of these proteins, all Aeromonas genomes deposited in the NCBI RefSeq genome database (1,222 genomes) were investigated. This revealed that these Aeromonas Qnr (AQnr) proteins are conserved intrinsic resistance determinants of the genus, exhibiting species-specific diversity. Additionally, structure prediction and analysis of contribution to quinolone resistance by AQnr proteins of the isolates, confirmed their functionality as quinolone resistance determinants. Given the origin of mobile qnr genes from aquatic bacteria and the crucial role of Aeromonas spp. in ARG dissemination in aquatic environments, a thorough understanding and strict surveillance of AQnr families prior to the clinical emergence are imperative. In this study, using comparative genome analyses and functional characterization of AQnr proteins in the genus Aeromonas, novel Aeromonas ARGs requiring surveillance has suggested.

• Applied Biological Chemistry
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• 제35권3호
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• pp.179-185
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• 1992

우리나라 남부지방(南部地方)의 5개(個) 산지(山地) 목초지(牧草地)에 분포한 알팔파근류균(根瘤菌) R. meliloti의 밀도(密度)와 실소고정력(室素固定力), 그리고 항생제(抗生劑) 반응(反應) 특성(特性)을 조사하였다. 그 결과(結果), 초지토양(草地土壤)에 분포한 R. meliloti 밀도(密度)는 $1.7{\times}10^2\;cells/g$.토양(土壤)(여주시(麗州市) 충효동(忠孝洞)) 내지 $1.0{\times}10^5\;cells/g$.토양(土壤)(경주군(慶州郡) 감포면(甘浦面)) 수준(水準) 이었으며, 토양 pH와는 정(正)의 상관(相關)을 보였다. 그리고, 초지토양(草地土壤)의 알팔파 접종효과(接種效果)로 본 토착(土着) R. meliloti의 질소고정력(窒素固定力)은 전반적으로 표준균주(標準菌株)인 TAL 접종제(接種劑) 보다 저조(低調)하였으나, 달성군(達城郡) 옥포면(玉浦面) 초지(草地)에서 분리(分離)된 YCKa 539, YCKa 542 2균주(菌株)는 비슷하거나 우수(優秀)한 질소고정력(窒素固定力)을 보였다. 초지토양별로 보면 경주군(慶州郡) 견곡면(見谷面)의 것이 가장 높았고, 다음으로 달성군(達城郡) 옥포(玉浦)>경주시(慶州市) 충효(忠孝)>달성군(達城郡) 화국(花國)>경주군(慶州郡) 감포(甘浦) 균주(菌株) 순(順)이었다. 분리균주(分離菌株)들은 항생제(抗生劑) Ery($100\;{\mu}g/ml$), Nal($160\;{\mu}g/ml$), Str($10\;{\mu}g/ml$)에 대해 각각(各各) 67%, 77%, 80%정도의 내성경향(耐性傾向)을 보이면서 전체적으로는 14개(個)의 항생제(抗生劑) 내성류형(耐性類型)으로 분류(分類)되었는데, 이들 류형(類型)과 균주(菌株)의 질소고정력간(窒素固定力間)에는 뚜렷한 관계경상(關係傾商)을 보이지 않았다. 그리고, 분리균주(分離菌株) 중(中)에서 질소고정력(窒素固定力)이 가장 우수(優秀)하였던 YCKa 542균주(菌株)는 Ery Nal, Neo, Str 내성인 X번형(番型)에 속하였다.

• 미생물학회지
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• 제51권4호
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• pp.440-443
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• 2015

임상과 자연환경에서 발견되는 항생제내성균의 문제는 보건학적 관심의 대상이 되고 있으며 환경 중의 미생물은 항생제 내성유전자 확산의 한 요인으로 판단되고 있다. 본 연구에서는 국내 하천 7지점으로부터 분리한 배양성 ampicillin 내성균의 다양성을 조사하였다. 분리된 498종의 세균들 중에서 Aeromonas와 Acidovorax 속의 내성균 분포가 가장 높았으며, 66%의 분리균들이 조사된 14종의 항생제 중 6종 이상의 항생제에 내성을 나타내었다. 그리고 7종의 항생제에 내성을 보이는 비율이 19.7%로 가장 높았다. 또한 항생제감수성 조사 결과를 바탕으로, 분포율이 높았던 Aeromonas, Acidovorax, Pseudomonas, Elizabethkingia 속의 내성균에 대한 자연내성 특징을 파악하였다.