Antibacterial Activity of an Ethyl Acetate Extract of Pseudomonas sp. UJ-6 against Methicillin-Resistant Staphylococcus aureus

  • Lee, Dae-Sung (POSTECH Ocean Science and Technology Institute, POSTECH) ;
  • Eom, Sung-Hwan (Department of Food Science and Technology, Pukyong National University) ;
  • Je, Jae-Young (Department of Marine Bio-Food Sciences, Chonnam National University) ;
  • Kim, Young-Mog (Department of Food Science and Technology, Pukyong National University) ;
  • Lee, Myung-Suk (Department of Microbiology, Pukyong National University) ;
  • Kim, Young-Man (Department of Food and Nutrition, Dong-Eui University)
  • Received : 2013.05.15
  • Accepted : 2013.06.03
  • Published : 2013.06.30


In an effort to discover an alternative antibiotic for treating infections with methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas sp. UJ-6, a marine bacterium that exhibited antibacterial activity against MRSA, was isolated. The culture broth and its ethyl acetate extract exhibited bactericidal activity against MRSA. The extract also exhibited antibacterial activity against gram-negative bacteria, which were not susceptible to vancomycin. The treatment of MRSA with the extract resulted in abnormal cell lysis. The extract retained >95% of its anti-MRSA activity after heat treatment for 15 min at $121^{\circ}C$. Thus, although most antibiotics are unstable under conditions of thermal stress, Pseudomonas sp. UJ-6 produces a heat-stable anti-MRSA substance. The results of this study strongly suggest that Pseudomonas sp. UJ-6 can be used to develop a novel, heat-stable, broad-spectrum antibiotic for the treatment of MRSA infections.



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