title: In vitro antibacterial effect of wasp (Vespa orientalis) venom.
abstract: BACKGROUND
  The emergence of antibacterial resistance against several classes of antibiotics is an inevitable consequence of drug overuse. As antimicrobial resistance spreads throughout the globe, new substances will always be necessary to fight against multidrug-resistant microorganisms. Venoms of many animals have recently gained attention in the search for new antimicrobials to treat infectious diseases. Thefore, the present study aimed to study the antibacterial effects of wasp (Vespa orientalis) crude venom. Two gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two gram-negative ones (Escherichia coli and Klesiella pneumonia) were compared for their sensitivity to the venom by determining the inhibition zone (Kirby-Bauer method) and minimum inhibitory concentration (MIC). A microbroth kinetic system based on continuous monitoring of changes in the optical density of bacterial growth was also used for determination of antimicrobial activity.
  
  
  RESULTS
  The venom exhibited a well-recognized antimicrobial property against the tested bacterial strains. The inhibition zones were determined to be 12.6, 22.7, 22.4 and 10.2 mm for S. aureus, B. subtilis, E. coli and K. pneumonia, respectively. The corresponding MIC values were determined to be 64, 8, 64 and 128 μg/mL, respectively. The MIC50 and MIC90 values of the venom were respectively determined to be 63.6 and 107 μg/mL for S. aureus, 4.3 and 7.0 μg/mL for B. subtilis, 45.3 and 65.7 μg/mL for E. coli and 74.4 and 119.2 μg/mL for K. pneumonia. Gram-positive bacteria were generally more sensitive to the venom than gram-negative ones.
  
  
  CONCLUSIONS
  Results revealed that the venom markedly inhibits the growth of both gram-positive and gram-negative bacteria and could be considered a potential source for developing new antibacterial drugs.
authors: Department of Pharmacology and Toxicology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran.
authors: Jafar
authors: J
authors: Jalaei
authors: Department of Pharmacology and Toxicology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran.
authors: Mehdi
authors: M
authors: Fazeli
authors: Department of Pharmacology and Toxicology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran.
authors: Hamid
authors: H
authors: Rajaian
authors: Department of Food Hygiene, School of Veterinary Medicine, Shiraz University, Shiraz, Iran.
authors: Seyed Shahram
authors: SS
authors: Shekarforoush
keywords: Antimicrobial activity; Minimum inhibitory concentration; Vespa orientalis; Wasp venom