항생제 노출에 따른 Klebsiella pneumoniae의 내성 특성

정래승,조아라,김정진,안주희,Jung, Lae-Seung,Jo, Ara,Kim, Jeongjin,Ahn, Juhee 한국미생물학회 2016 미생물학회지 Vol.52 No.4

항균제에 대한 내성 증가는 국내뿐만 아니라 세계적으로도 인류 건강에 큰논란이 되고 있다. 박테리아에 의한 감염을 치료하기 위해 같은 혹은 다른 계열의 항생제에 순차적으로 노출된다. 따라서, 본 연구는 ciprofloxacin과 meropenem의 순차적 처리에 따른 폐렴간균(Klebsiella pneumoniae)의 생육, 항생제 민감성, 돌연변이 빈도, ${\beta}$-lactamase activity, 생물막 형성 및 내성 관련 유전자 발현을 평가하기 위해 설계되었다. 처리군은 대조군(control; CON), 1/2 MIC ciprofloxacin (1/2CIP), 2 MIC ciprofloxacin (2CIP), 1/2 MIC ciprofloxacin+1/2 MIC meropenem+2 MIC ciprofloxacin (1/2CIP-1/2MEM-2CIP), 1/2 MIC ciprofloxacin+1/2 MIC meropenem+2 MIC meropenem(1/2CIP-1/2MEM-2MEM), 1/2 MIC ciprofloxacin+2 MIC ciprofloxacin+2 MIC meropenem (1/2CIP-2CIP-2MEM)을 포함한다. 24시간의 배양 동안 2CIP처리군에서 K. pneumoniae의 생육이 관찰되지 않았다. 모든 처리군에서 planktonic cell의 수는 7에서 10 log CFU/ml의 유의적인 차이를 보였으나 biofilm cell의 수는 7 log CFU/ml로 비슷하였다. 돌연변이 빈도는 1/2CIP-1/2MEM-2CIP에서 가장 낮은 14%을 보였다. 대조군과 비교하여 1/2CIP-2CIP-2MEM 처리 K. pneumoniae는 piperacillin, cefotaxime, nalidixic에 대한 민감도가 감소되었다. 1/2CIP-1/2MEM-2CIPrk 가장 높은 ${\beta}$-lactamase activity(22 nmol/min/ml)을 보인 반면 1/2CIP-2CIP-2MEM은 가장 낮은 ${\beta}$-lactamase activity (6 nmol/min/ml)을 보였다. Multidrug efflux pump 관련 유전자(acrA, acrB, and ramA)의 발현은 1/2CIP-1/2MER-2MER and 1/2CIP2CIP-2MER 처리된 K. pneumoniae에서 2배 이상 증가하였다. 따라서 순차적 항생제의 처리는 K. pneumoniae의 항생제 내성 양상을 변화시킬 수 있다. The emergence of antibiotic-resistant bacteria has been increased and become a public health concern worldwide. Many bacterial infections can be sequentially treated with different types of antibiotics. Thus, this study was designed to evaluate the changes in survival, antibiotic susceptibility, mutant frequency, ${\beta}$-lactamase activity, biofilm formation, and gene expression in Klebsiella pneumoniae after exposure to sequential antibiotic treatments of ciprofloxacin and meropenem. Treatments include control (CON; no addition), 1/2 MIC ciprofloxacin addition (1/2CIP), 2 MIC ciprofloxacin addition (2CIP), initial 1/2 MIC ciprofloxacin addition followed by 1/2 MIC meropenem (8 h-incubation) and 2 MIC ciprofloxacin (16 h-incubation) (1/2CIP-1/2MER-2CIP), initial 1/2 MIC ciprofloxacin addition followed by 1/2 MIC meropenem (8 h-incubation) and 2 MIC meropenem (16 h-incubation) (1/2CIP-1/2MER-2MER), and initial 1/2 MIC ciprofloxacin addition followed by 2 MIC ciprofloxacin(8 h-incubation) and 2 MIC meropenem(16 h-incubation) (1/2CIP-2CIP-2MER). No growth of K. pneumoniae was observed for the 2CIP throughout the incubation period. The numbers of planktonic cells varied with the treatments (7~10 log CFU/ml), while those of biofilm cells were not significantly different among treatments after 24-h incubation, showing approximately 7 log CFU/ml. Among the sequential treatments, the least mutant frequency was observed at the 1/2CIP-1/2MER-2CIP (14%). Compared to the CON, 1/2CIP-2CIP-2MER decreased the sensitivity of K. pneumoniae to piperacillin, cefotaxime, and nalidixic acid. The highest ${\beta}$-lactamase activity was 22 nmol/min/ml for 1/2CIP-1/2MER-2CIP, while the least ${\beta}$-lactamase activity was 6 nmol/min/ml for 1/2CIP-2CIP-2MER. The relative expression levels of multidrug efflux pump-related genes (acrA, acrB, and ramA) were increased more than 2-fold in K. pneumoniae exposed to 1/2CIP-1/2MER-2MER and 1/2CIP-2CIP-2MER. The results suggest that the sequential antibiotic treatments could change the antibiotic resistance profiles in K. pneumoniae.

Assessment of Pressure-induced Inactivation of Listeria monocytogenes Exposed to Low pHs

정래승,이현용,이승환,김성균,안주희 한국식품과학회 2013 Food Science and Biotechnology Vol.22 No.1

This study was designed to evaluate the morphological and physiological characteristics of high pressure (HP)-treated Listeria monocytogenes treated at different pHs. L. monocytogenes in phosphate buffered saline (PBS, pH 7.2) adjusted with HCl or lactic acid to pH 4.0, 5.0, and 6.0 was subjected to 300 MPa for 5 min. The numbers of HP-treated L. monocytogenes at pH 4.0adjusted with HCl or lactic acid were reduced by more than 6 log CFU/mL, while the numbers of non-HP-treated L. monocytogenes were not significantly reduced at pH 4.0. The propidium iodide (PI) fluorescence intensity of HPtreated cells adjusted with lactic acid was increased from 65 (pH 6.0) to 78% (pH 4.0). The HP-induced inactivation of L. monocytogenes in low pH was not directly associated with the membrane disruption. The results provide valuable information for understanding the HP-induced inactivation mechanisms and enhancing microbial lethality in acidic food systems.

Effect of High Pressure Processing on Microbiological and Physical Qualities of Carrot and Spinach

정래승,이승환,김성균,이성기,안주희 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.3

This study was designed to evaluate the microbiological and physicochemical properties of carrot and spinach treated at 100, 300, and 500 MPa for 20 min. The numbers of Salmonella Typhimurium cells were significantly reduced by more than 5 log CFU/g in carrots and spinaches treated at 500 MPa after 5 min. The color changes were noticeable in the cooked carrots (ΔE>9) and spinaches (ΔE>12). Two distinct phases were observed in the textural changes of carrots and spinaches under high pressure processing. These results provide useful information for understanding microbial inactivation, color changes, and textural properties in high pressure-treated carrot and spinach samples.

Antioxidant, Antibiofilm, and Anticholinesterase Activities of Fermented Deodeok (Codonopsis lanceolata) Extracts

정래승,Xinlong He,송치호,마충제,이현용,안주희 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.5

This study was designed to evaluate the antioxidant, antimicrobial, antibiofilm, and anticholinesterase activities of different solvent fractions from non-fermented (NF) and Lactobacillus rhamnosus fermented deodeok (Codonopsis lanceolata) (LRF). The highest amounts of total phenols and flavonoids were observed in chloroform fraction from NF (72 and 31 mg RE/g) and LRF (79 and 24 mg RE/g). The ferric reducing antioxidant power (FRAP) values were highly correlated with the DPPH scavenging activity, showing that the highest FRAP values were observed in chloroform fractions from NF (35 mM Fe(II)/g) and LRF (50 mM Fe(II)/g). Staphylococcus aureus biofilm cells were highly susceptible to chloroform fraction, showing 1.8 log reductions. The highest anticholinesterase activity was observed in chloroform and ethyl acetate fractions from LRF (1.5 mg/mL<EC50<2.5mg/mL). The results provide useful information for improving pharmacological activities and also suggest new direction for developing biologically active compounds from medicinal plants.

Effect of High Hydrostatic Pressure on the Quality-related Properties of Carrot and Spinach

정래승,이승환,김성균,안주희 한국식품과학회 2013 Food Science and Biotechnology Vol.22 No.suppl1

This study was designed to evaluate the potential effectiveness of high hydrostatic pressure (HHP) on the changes in quality-related properties of carrot and spinach as measured by ascorbic acid, carotenoids, phenols,flavonoids, microstructure, enzyme activity, and antioxidant activity. Better retention of ascorbic acid and carotenoids was observed at the carrots and spinaches treated at 100,300, and 500 MPa for 20 min compared to the thermal processing. The color differences were noticeable at the carrot treated at 500 MPa (ΔE=3.5) and the spinach treated at 100 MPa (ΔE=3.6). The least residual peroxidase (POD)activity was 16.6% at the carrot at 300 MPa. The residual polyphenoloxidase (PPO) activities were decreased in carrot (15.1-6.9%) and spinach (31.1-21.3%) and the amounts of phenols flavonoids were increased with increasing pressure levels, leading to the enhanced antioxidant activity. Therefore, the HHP could be used as an alternative for improving quality of vegetables.

증숙 및 발효 더덕의 이화학적 특성 및 생리활성 변화

정래승(Lae-Seung Jung),윤원병(Won-Byung Yoon),박성진(Sung-Jin Park),박동식(Dong-Sik Park),안주희(Juhee Ahn) 한국식품과학회 2012 한국식품과학회지 Vol.44 No.1

본 연구에서는 증숙 및 발효에 의한 더덕(Codonopsis lanceolata)의 이화학적 특성과 생리활성의 변화에 미치는 영향에 대해 조사하였다. 건조된 더덕 시료를 증숙처리한 후 Lactobacillus rhamnosus를 접종하여 37℃에서 7일간 혐기적 조건에서 발효시켰다. 비증숙과 비발효 더덕추출물(NS-NF)을 대조군으로 하여 처리군에는 비증숙과 발효 더덕추출물(NS-LF), 증숙과 비발효 더덕추출물(S-NF), 증숙과 발효 더덕추출물(S-LF)을 포함한다. 총 폴리페놀성 화합물 함량은 NS-NF(8.9 mg GAE/g)와 비교하여 S-NF와 S-LF에서 유의적으로 증가되었다(26 mg GAE/g). 총 플라보노이드 함량은 S-NF(8.1 mg RE/mL)와 S-LF(7.8 mg RE/mL)에서 가장 높았다. S-NF와 S-LF의 EC<SUB>50</SUB> 값이 각각 0.8과 0.6 mg/mL으로 높은 항산화능을 보였다. Staphylococcus aureus, Listeria monocytogenes, Salmonella Typhimurium, Shigella boydii의 생육은 S-LF에 의해 효과적으로 저해되었다(MIC<9 mg/mL). NS-NF(EC<SUB>50</SUB><17 mg/mL)에 비교하여 NS-LF와 S-LF(EC<SUB>50</SUB><6 mg/mL)가 가장 높은 α-glucosidase와 tyrosinase 저해효과를 나타냈다. Aacetylcholinesterase(AChE)는 S-LF(IC<SUB>50</SUB><32 mg/mL)에 의해 효과적으로 저해되었다. 따라서 본 연구의 결과는 증숙에 의해 더덕의 총 페놀함량, 플라보노이드 함량, 항산화능이 향상되었으며 발효에 의해 특이적으로 항미생물 효과, 효소활성저해 및 인지기능 개선 등과 같은 생리활성을 효과적으로 증진시켰다. This study was designed to evaluate the physicochemical properties and biological activities of steamed and fermented Codonopsis lanceolata. The treatments included NS-NF (non-steamed and non-fermented), NS-LF (non-steamed and L. rhamnosus fermented), S-NF (steamed and non-fermented), and S-LF (steamed and L. rhamnosus fermented). Total polyphenol amounts of S-NF and S-LF were significantly increased to more than 26 mg GAE/g. The highest DPPH scavenging activities were observed for S-NF and S-LF, showing EC<SUB>50</SUB> values of 0.8 and 0.6 mg/mL, respectively. The growths of Staphylococcus aureus, Listeria monocytogenes, Salmonella Typhimurium, and Shigella boydii were effectively inhibited by S-LF (MIC<9 mg/mL). The NS-LF and S-LF (EC<SUB>50</SUB><6 mg/mL) effectively inhibited α-Glucosidase and tyrosinase activities compared to NS-NF (EC<SUB>50</SUB><17 mg/mL). The S-LF exhibited the highest acetylcholinesterase (AChE) inhibitory activity (IC<SUB>50</SUB><32 mg/mL). Therefore, the results suggest that the application of the steaming process combined with probiotic fermentation can effectively enhance the biological and pharmacological activities in C. lanceolata.