• Journal of Microbiology and Biotechnology
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• 제25권7호
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• pp.1015-1025
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• 2015

The development of diverse polymyxin derivatives is needed to solve the toxicity and resistance problems of polymyxins. However, no platform has generated polymyxin derivatives by genetically engineering a polymyxin synthetase, which is a nonribosomal peptide synthetase. In this study, we present a two-step approach for the construction of engineered polymyxin synthetases by substituting the adenylation (A) domains of polymyxin A synthetase, which is encoded by the pmxABCDE gene cluster of Paenibacillus polymyxa E681. First, the seventh L-threonine-specific A-domain region in pmxA was substituted with the L-leucine-specific A-domain region obtained from P. polymyxa ATCC21830 to make polymyxin E synthetase, and then the sixth D-leucine-specific A-domain region (A_6-D-Leu-domain) was substituted with the D-phenylalanine-specific A-domain region (A_6-D-Phe-domain) obtained from P. polymyxa F4 to make polymyxin B synthetase. This step was performed in Escherichia coli on a pmxA-containing fosmid, using the lambda Red recombination system and the sacB gene as a counter-selectable marker. Next, the modified pmxA gene was fused to pmxBCDE on the chromosome of Bacillus subtilis BSK4dA, and the resulting recombinant strains BSK4-PB and BSK4-PE were confirmed to produce polymyxins B and E, respectively. We also succeeded in constructing the B. subtilis BSK4-PP strain, which produces polymyxin P, by singly substituting the A_6-D-Leu-domain with the A_6-D-Phe-domain. This is the first report in which polymyxin derivatives were generated by genetically engineering polymyxin synthetases. The two recombinant B. subtilis strains will be useful for improving the commercial production of polymyxins B and E, and they will facilitate the generation of novel polymyxin derivatives.

• 대한미생물학회지
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• 제6권1호
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• pp.29-40
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• 1971

Various kinds of antibiotics are generally believed to have inhibitory effects on the antibody response. However, as polymyxin B which belongs to the cyclic polypeptide group of antibiotic was found to have some enhancing effects on the antibody response of rabbits to enterobacterial common antigen(CA) under specified conditions, experiments were carried out on this problem with the following results. 1. When mixture of polymyxin B and CA derived from Salmonella typhimurium(STM) was treated 30 minutes at $37^{\circ}C$ and injected three times into rabbits by intravenous route, the antibody response to CA was weaker than rabbits injected CA only. 2. Mixture of polymyxin B and CA showed a marked antibody production when injected into rabbits primed with small amounts of heat-extracted antigen of STM, while the injection of CA alone showed low titers of response. 3. Mixture of polymyxin B and heat-extracted CA-containing antigen of Escherichia coli 014 also showed a increased antibody production than CA alone in rabbits primed with antigen of STM. 4. The effect of polymyxin B appeared in different ways. This antibiotic did not enhance the CA antibody response in rabbits primed with small amounts of E. coli 0111 and 055, but enhance in rabbits primed with Shigella flexneri. 5. No enhancing effect on the antibody response was observed by polymyxin B in rabbits primed with CA. 6. No enhancing effect on the antibody response was also noted in rabbits primed with STM antigen in case polymyxin B and CA were administered simultaneously but in veins of different places. 7. Bacitracin did not enhance the CA antibody response in primed rabbits with STM antigen, but neomycin slightly enhance the response. 8. Lipopolysaccharide showed no priming effect on the CA antibody response, and no enhancement of the CA antibody response in rabbits printed with STM. 9. The priming effect of STM antigen against CA antibody response was very weak as compared with the effect of CA derived from STM antigen.

• 한국임상수의학회지
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• 제27권1호
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• pp.6-10
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• 2010

2003년부터 2009년까지 서울 지역 동물병원에 의뢰된 세균성 요로 감염증 개의 병소에서 세균의 분리빈도와 항생제 감수성을 조사한 결과는 다음과 같다. 세균성 요로 감염증 개의 뇨에서 Escherchia coli 27주, Streptoococcus spp. 7주, Staphylococcus spp. 5주, Enterobacter spp. 3주, Proteus spp. 2주, 그리고 기타 세균 3주, 총 47주의 세균이 분리되었다. 이 중 분리 빈도가 높은 E. coli, Streptoococcus spp. 및 Staphylococcus spp.를 대상으로 항생제 감수성을 조사하였다. E. coli의 항생제 감수성은 imimpenem, polymyxin B, amikacin, cephalosporins, aztreonam, amoxicillin clavulate, cephalosporins, tricarcillin, amoxicillin clavulate 순으로 나타난 반면 bacitracin, erythromycin, lincomycin, oxacillin, penicillin, novobiocin 등에 대해서는 높은 내성을 나타내었다. Streptoococcus spp.의 항생제 감수성은 bacitracin, imimpenem, trimethoprime-sulfa 순이었고 amikacin, cefotaxim, cefoxitin, cloxacillin, gentamicin, lincomycin, oxacillin, penicillin, streptomycin, tobramycin에는 매우 높은 내성을 나타내었다. Staphylococcus spp.의 항생제 감수성은 cefoxitin, doxycycline, enrofloxacin, imimpenem, tobramycin에 매우 높았고 aztreonam, tetracycline에 내성을 나타내었다.

• Macromolecular Research
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• 제13권6호
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• pp.549-552
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• 2005

• 생명과학회지
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• 제14권4호
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• pp.664-669
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• 2004

국민 다소비 식품인 생선회, 패류 등의 횟감류 118건, 김밥, 햄버거 등의 도시락류 82건 및 기타 ready-to-eat(RTE) 식품 40건, 총 240건을 대상으로 Bacillus cereus의 오염실태를 조사한 결과, 횟감류 16건(13.6%), 도시락류 17건(20.7%), 기타 RTE 식품에서 3건(7.5%), 총 36건(15.0%)에서 B. cereus가 검출되었다. B. cereus의 검출은 polymyxin B를 첨가한 TSB배지를 사용한 증균배양 후, MYP agar에서 전형적인 집락을 선별하였으며, 선별된 균주들을 대상으로 그람염색, oxidase test, 혈액한천배지에서의 rhizoid growth, $\beta$-용혈성 유ㆍ무등을 통해 추정 균주들을 분리하였다. API 50CHB/20E system을 통한 생화학적 분석과 motility시험 등을 행하여 최종적으로 B. cereus로서 동정ㆍ확인하였다. 확인된 36균주 중 28균주(77.8%)가 BCET-RPLA 시험을 통해 BHI broth에서 설사형 독소를 생성하는 것으로 나타났다. 아울러 항생제 감수성 시험 결과 분리균들은 ampicillin (100%), penicillin G (100%) 및 rifampicin (69.5%)에 내성을 보였으며, gentamicin (100%), vancomycin (100%), bacitracin (86.1%), chloram-phenicol (97.2%), erythromycin (69.4%), kanamycin (86.1%) 및 streptomycin (97.2%)에 감수성을 나타내었다. B. cereus의 생육은 온도와 시간에 밀접한 관련성을 보였는데, 냉장온도인 1$0^{\circ}C$이하에서는 균의 생육이 상당히 저해된 반면, 2$0^{\circ}C$ 및 3$0^{\circ}C$에 보관시에는 급격한 증식을 보여 기온이 상승하는 하절기에 특히 많은 주의가 필요하다고 판단되었다.

• Toxicological Research
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• 제13권1_2호
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• pp.111-116
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• 1997

In the present study, we investigated the neutralization activity of various antimicrobials against lipopolysaccharide (LPS) as well as interaction between two antimicrobials (enrofioxacin and coilstin) using checkerboard method. The neutralization activity of antimicrobials used in the test was assayed by means of LAL chromogenic test after reaction of LPS with colistin, enorfioxacin, ampicillin, polymyxin B, oxytetracycline, streptomycin, and erythromycin. As the results, the neutralization activity of coltstin and polymixin B had a more stronger than that of tested other antimicrobials. In bacterial culture broth, the best neutralization activity of the antibiotics was also shown to coltstin and polymixin B. Meanwhile, It was shown to have synergism between enorfloxacin and coltstin on the basts of FIC (fractional inhibition concentration). The FIC of enorfioxacin-colistin combinations was 0.50-1.03 to Staphylococcus aureus R-209, 1.03-1.06 to Salmonella typhimurium, 0.75-1.25 to Bordetella Bronchtseptica and 1.02-1.25 to E. coli K88ab. On the basts of the above results, the present study may be of clinical usefulness in the choice of an antibiotic therapy for severe sepsts in animals.

• International Journal of Oral Biology
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• 제30권1호
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• pp.31-37
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• 2005

Treponema maltophilum, a Group IV oral spirochete, is associated with periodontitis and endodontic infections. In this study we analyzed the functional role of the major surface protein of this organism (MspA) in human gingival fibroblasts (HGFs). The full-length gene encoding MspA was cloned and expressed in Escherichia coli by using the expression vector pQE-30. The recombinant protein (rMspA) was purified by affinity chromatography with nickel-nitrilotriacetic acid agarose and possible contamination of E. coli endotoxin in rMspA was removed by using polymyxin B-agarose. rMspA significantly induced the expression of pro inflammatory cytokines like IL-6 and IL-8 and intercellular adhesion molecule (ICAM)-1 in HGFs, when analyzed by reverse transcription-PCR, flow cytometry, and enzyme-linked immunosorbent assay. Our results indicate that MspA of T. maltophilum may play an important role in amplifying the local immune response by upregulating the expression of proinflammatory cytokines and ICAM-1.

• 대한수의학회지
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• 제61권2호
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• pp.16.1-16.6
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• 2021

Pseudomonas aeruginosa is one of the most common pathogenic species associated with canine otitis externa (OE). Their resilience is achieved by forming a biofilm, which allows these bacteria to evade even the harshest of treatments. This study evaluated the in vitro synergistic efficacy of N-acetylcysteine (NAC) with different antimicrobial agents against P. aeruginosa isolated from dogs with OE to develop an effective treatment against P. aeruginosa. The antimicrobial activity was evaluated by the minimum inhibitory concentration test using the microdilution method. The efficacy of antibiofilm formation was evaluated using a crystal violet stain method. The treatment solutions included NAC alone, and in synergy with enrofloxacin, polymyxin B, and gentamicin. NAC alone exhibited antimicrobial and antibiofilm abilities. On the other hand, the combination of NAC and the antibiotics did not show any significant synergistic effects against P. aeruginosa.

• 대한미생물학회지
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• 제18권1호
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• pp.39-46
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• 1983

We collected three hundred thirty-five strains of Salmonella typhi isolated from human sources during the period January to December 1982 Korea. Most of them were from general hospitals and city health center, the remaining one hundred sixtyone strains were obtained from other 12 provincial health centers among 335 testing strains. We used ninety-nine Vi-phages as distributed from International Center for Enteric phage Typing(ICEPT) in London. We found nine phage types among 335 strains of Salmonella typhi in this study. Additionally, I+IV, degraded Vi-positive and Vi negative strains were presented. This study documented the occurrence of the new $B_2$ type in Korea for the first time. The present basic phage type formula in Korea appeared to be A, $B_2,\;D_1,\;D_2,\;D_4,\;D_6,\;D_8,\;D_{12},\;E_1,\;E_9,\;D_1,\;M_1$, 40 and plus I+IV and degraded vi strains(Table 2). The current phage types of Salmonella typhi isolated in Korea 1982 were A, $B_2,\;D_1,\;D_2,\;D_6,\;D_8,\;E_1,\;M_1$ and 46 $M_1$ type was widely distributed all over the country, and E type was next predominant. Antibiotic susceptibility test were performed by means of Kirby-Bauer disc diffution method using 12 kind of antibiotics such as Ampicillin, Carbenicillin, Cephalosporin, Chloramphenicol, Colistin, Gentamicin, Kanamycin, Nalidix acid, Neomycin, Polymyxin-B, Streptomycin and Tetracycline. The sensitivity pattern to antibiotics of Salmonelia typhi cultures were summarized.

• 동아시아식생활학회지
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• 제19권5호
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• pp.798-802
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• 2009

시판되는 112점의 생식제품에서 대장균(Escherichia coli), 클로스트리디움 퍼프린젠스(Clostridium perfringens), 바실러스 세레우스(Bacillus cereus) 등의 오염 미생물을 분석하여 식품공전 기준 규격에 적합한지를 알아보았다. E. coli는 모든 생식제품에서 검출되지 않았다. C. perfringens는 11제품(9.8%)에서 검출되었고 $10^2$ CFU/g으로 기준 규격에 적합하였다. B. cereus는 25제품(23.3%)에서 검출되었고, 5제품에서 $10^2$CFU/g 이하, 7품에서 $10^2{\sim}10^3$ CFU/g, 13제품에서 $10^3{\sim}10^4$ CFU/g으로 검출되었다. 이 분리 세균은 전형적인 특성을 보이고 있었는데 TSC agar, MYP agar에서 검출된 균은 그람양성 및 간균이었으며, 생화학 테스트 결과 egg-yolk의 지질을 분해할 수 있는 lecithinase를 가지고 있는 것으로 확인되었다. 그러므로 유통되고 있는 생식 제품의 일부는 식품공전의 기준 규격을 초과하는 B. cereus가 검출되어 보다 더 철저한 세균 제어 관리가 필요하다고 사료된다.