The aim of this study was to investigate the efficacy of 11 essential oils (EOs) against Staphylococcus pseudintermedius planktonic and biofilm forms. Twenty three bacterial samples were collected from dogs with superficial pyoderma and 9 samples were identified as S. pseudintermedius by polymerase chain reaction-restriction fragment length polymorphism method. The minimum planktonic inhibitory concentration (MPIC), minimum planktonic bactericidal concentration (MPBC) and minimum biofilm eradication concentration (MBEC) of EOs were determined by broth microdilution using a transferable solid phase. Among all, lemongrass EO was the most effective against both planktonic and biofilm forms of S. pseudintermedius with the MPIC, MPBC and MBEC of 0.02, 0.039 and 0.078% v/v, respectively. EOs of betel vine and citronella had the second most inhibitory effect (MPIC and MPBC: 0.039% v/v and MPBC: 0.156% v/v) followed by clove (MPIC and MPBC: 0.078% v/v) and sweet basil (MPIC and MPBC: 0.625% v/v). The EOs of ginger, plai, kaffir lime, turmeric, holy basil and galanga had the lowest inhibitory effect with MPICs and MPBCs ranging from 1.25% v/v to greater than 2.5% v/v. The results of this study indicated that the anti-planktonic and anti-biofilm effects of the tested EOs were concentration dependent, and higher concentrations were required for anti-biofilm activity. Lemongrass EO showed the most potential as a therapeutic antimicrobial agent for both planktonic and biofilm forms of S. pseudintermedius.

This study aimed to investigate the concentrations of Cr, Cd and Pb in the water, sediment and experimental hybrid catfish muscles, and to compare the genetic differentiation and the levels of oxidative stress biomarkers (malondialdehyde and protein carbonyl) between the catfish from the contaminated reservoir near a municipal landfill and the reference area after chronic exposure. The concentrations of all metals in the water and the concentration of Cd in the sediment exceeded Thailand’s surface water quality and soil quality standards, respectively, whereas the concentrations of these metals in fish muscles did not exceed Thailand’s food quality standards. Dendrogram results in terms of genetic similarity values of the catfish from the reference and the landfill areas were 0.90 to 0.96 and 0.79 to 0.86, respectively, implying that the genetic differentiation of the fish from the landfill was greater than of those from the reference area. The fish in the landfill reservoir had slightly increased protein carbonyl levels. The results indicate that chronic heavy metal exposure can cause genotoxicity of the hybrid catfish and induce protein carbonyl as an oxidative stress biomarker in the reservoir near a municipal landfill.