• Journal of Microbiology and Biotechnology
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• v.26 no.12
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• pp.2159-2170
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• 2016

Many plant-pathogenic bacteria are dependent on quorum sensing (QS) to evoke disease. In this study, the population of QS and quorum quenching (QQ) bacteria was analyzed in a consecutive monoculture system of Pseudostellaria heterophylla. The isolated QS strains were identified as Serratia marcescens with SwrIR-type QS system and exhibited a significant increase over the years of monoculture. Only one QQ strain was isolated from newly planted soil sample and was identified as Bacillus thuringiensis, which secreted lactonase to degrade QS signal molecules. Inoculation of S. marcescens to P. heterophylla root could rapidly cause wilt disease, which was alleviated by B. thuringiensis. Furthermore, the expression of lactonase encoded by the aiiA gene in S. marcescens resulted in reduction of its pathogenicity, implying that the toxic effect of S. marcescens on the seedlings was QS-regulated. Meanwhile, excess lactonase in S. marcescens led to reduction in antibacterial substances, exoenzymes, and swarming motility, which might contribute to pathogensis on the seedlings. Root exudates and root tuber extracts of P. heterophylla significantly promoted the growth of S. marcescens, whereas a slight increase of B. thuringiensis was observed in both samples. These results demonstrated that QS-regulated behaviors in S. marcescens mediated by root exudates played an important role in replanting diseases of P. heterophylla.

• Journal of Yeungnam Medical Science
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• v.3 no.1
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• pp.185-192
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• 1986

Antimicrobial susceptibility of the bacterial strains isolated from clinical specimens during the period from June, 1983 to June, 1986 in Yeungnam Medical Center was studied and the following results were obtained. 1. Staphylococcus aureus was highly susceptible to cephalothin and its susceptibility to methicillin was gradually reduced. 2. Streptococcus strains except enterococcus were generally susceptible to penicillin, while most enterococci were suscesceptible to only ampicillin. 3. Gram-negative rods including Escherichia coli were highly susceptible to amikacin and tobramycin. 4. Serratia were generally less susceptible to the amtimicrobials tested than other Enterobacteriaceae. Among them, Serratia marcescens showed the highest susceptibility to amikacin and chloramphenicol. 5. Pseudomonas aeruginosa revealed the highest susceptibility to amikacin and tobramycin and moderate susceptibility to carbenicillin and gentamycin. 6. Acinetobacter calcoaceticus revealed low susceptibility to most antimicrobials tested, showing only 30% susceptibility to amikacin, tobramycin and gentamycin in 1986.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.237-237
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• 1996

DA-1131, imipenem(IPM) 및 meropenem(MEPM)은 각종 $\beta$-lactamase를 산생하는 세균에 대하여 우수한 항균력을 나타내었으나 cefpirome(CPR), ceftazidime(CAZ) 및 azthreonam(AZT)의 경우에는 extended broad spectrum cephalosporinase 산생 균주를 포함하여 일부 균주의 내성획득이 확인되었다. DA-ll3l의 $\beta$-lactamase Inducible activity는 DA-1131, IPM 및 MEPM이 거의 동일하였으며, imipenemase 산생균주로 동점된 Serratia marcescens 11001이 산생하는 $\beta$-lactamase이외의 효소에는 대부분 가수분해되지 않는 결과를 나타내었다. S. marcescens 11001이 산생하는 $\beta$-lactamase에 대한 효소역학상수는 DA-1131, IPM 및 MEPM에서 모두 유사하였고, $\beta$-lactamase에 대한 affinity도 큰 차이를 나타내지 않았다.

• Korean Journal of Microbiology
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• v.15 no.4
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• pp.159-169
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• 1977

The bacteria of red colonies isolated from soil were identified as Serratia marcescens. The best solvent for pigment extraction was n-buthanol and the pigment was identified as prodigiosene. The extracted pigment was stable on temperature and light but not on acidity. The redpigment color changed into red in alkaline solution. The maximum absorbancy of pigment was 466 nm in alkaline condition and 540 nm in acid condition. And the pigment formed single spot on the TLC(starch). By the result of infra red spectrum, the red pigment has the same absorption pattern comparing with, the prodigisin produced by S. marcescens strain Nima. It was confirmed that the pigment was secondary metabolite and that the maximal peak of production appeared at 30 hrs after the inoculation, when the bacterial growth was in statinary state. Referring to the effect of temperature, the pigment was not formed at $36^{\circ}C$ and the optimal temperature for both of bactrial growth and pigmentation was $30^{\circ}C$. The optimal range of pH for pigmentation was 5.0 and under the condition the bacterial growth was not affected at all. Examining the effects of light, the bacterial pigment ation was more increased in darkness than in visible light.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.3
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• pp.214-220
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• 2020

Handwashing with soap is an important practice to reduce the transmission of potentially pathogenic microorganisms, but liquid soaps with refillable dispensers are prone to extrinsic bacterial contamination. This study investigated the bacterial contamination of liquid soaps in 58 public restrooms in six buildings. The bacteria were identified by a biochemical test and MALDI-TOF mass spectrophotometry. The antimicrobial susceptibility was determined using the Vitek II system. Of the 58 restrooms examined, 27(46.55%) were using a refill dispenser, of which 25(92.59%) were contaminated with bacteria. The bacteria recovered from the soaps ranged from 1.6×10³ to 2.7×10⁵ CFU/mL. Serratia liquefaciens (12), Achromobacter xylosoxidans (9), S. marcescens (4), Staphylococcus pastueri (1), and Achromobacter spanius (1) were isolated. Except for one A. xylosoxidans, bacteria of the same species isolated in the same building showed a unique resistance pattern. In conclusion, handwashing with contaminated soap may play a role in the transmission of bacteria in public health settings. Therefore, it is necessary to limit the use of refillable liquid soaps in the restrooms of hospitals used by patients with reduced immunity.

• KSBB Journal
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• v.11 no.6
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• pp.696-703
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• 1996

The bacterium Serratia marcescens QM Bl466 produces selectively large amount of chitinolytic enzymes(about 1mg/L medium). Enzymatic hydrolysis of chitin to N-acelyl-${\beta}$-D-glucosamine(NAG) is performed by a system consisting of two hydrolases : chitinase and chilobiase. Objectives of this study included optimization of a microbial host by using chitin particles for chitinase/chitobiase production and secretion and also development of batch fermentation system for high cell density cultivalion of S. marcescens QM B1466. Also, the influence of chitin source and carboxymethyl(CM) chitin on chitinase/chitobiase production and NAG production was investigated. When carboxymethyl chitin was substituted for colloidal and practical grade chitin, the chitinase activity was increased about 7∼10U/mL. In this case, the ratio of chitinase/chitobiase was 30.03U/3.44U(9:1). The highest amounts of NAG(3.0g/L) was obtained.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.233-233
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• 1996

배지의 영향에 대하여 검토하기 위하여 SDA, MHA, NA 및 BHIA를 사용하였으며, 시험균주 중 Pseudomonas aeruginosa에 대하여만 NA에서의 MIC 값이 낮게 나타났을 뿐 나머지 균주에 대하여는 배지에 따른 항균력 변화가 관찰되지 않았으며, 배지의 pH를 5.4-8.4까지 변화시켰을 때 pH 변화에 따른 DA-1131의 유의적인 항균력 변화와 접종균량에 따른 항균력 변화가 관찰되지 않았다. Methicillin-resistant Staphylococcus aureus(MRSA)에 대하여는 DA-1131과 vancomycin 간의 상승 및 상가작용이 관찰되었고, P. aeruginosa, Klebsiella pneumoniae, Enterobacter cloacae 및 Serratia marcescens 등의 균종에 대하여는 ciprofloxacin의 상가작용이 확인되었다. Sisomicin은 P. aeruginosa에 대한 상승 및 상가작용이 인정되었으나 ceftazidime은 DA-1131에 의한 길항작용이 관찰되었다.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.331.3-332
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• 2002

A novel penicillin G acylase (PGA)-producing bacterial strain was isolated from soil by using the Serratia marcescens overlay technique. The isolated strain was identified as Leclercia adecarboxylata based on the analyses of the biochemical characteristics (API 20E). the cellular fatty acid profile. and the 16S rDNA sequences. The gene encoding the PGA (pac gene) was cloned into the pHSG399 vector and the recombinant E. coliHB101 clones harboring the pac gene were isolated on agar plates containing phenylacetyl-L -leucine and penicillin G. (omitted)

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.379-380
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• 2005

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.48-55
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• 2004

Six strains of an obligate predatory bdellovibrio isolate that preys on Burkholderia glumae in rice paddy field water and rhizosphere soil, were identified and characterized. The numbers of Bdellovibrio cells varied from $3.2{\times}10^3$ to $9.2{\times}10^3$ plaque-forming unit/g after enrichment in cells of B. glumae. Prey range tests with six Bdellovibrio strains and 17 prey strains of rice-pathogenic, antibiosis-related, or nitrogen-fixing bacteria resulted in unique predation patterns in related prey cells. Strain BG282 had the widest prey range on 7 plant pathogenic bacteria among the 17 prey strains tested. However, no predation occurred with strains of Azospirillum brasilense, Paenibacillus polymyxa, Pseudomonas fluorescens, P. putida, and Serratia marcescens that are associated with antibiosis or nitrogen fixation in the rice ecosystem. Identification was confirmed by the presence of typical bdelloplast in the prey cells of B. glumae and by a PCR assay using B. bacteriovorus-specific primers. Furthermore, 16S rDNA sequencing of the six bdellovibrio strains showed a homology range of 97.2% to 99.2% to the type strain of B. bacteriovorus.