In burn centers, Pseudomonas aeruginosa acts as a major cause of nosocomial infections. Therefore, this study aimed to characterize molecularly P. aeruginosa isolates collected from environmental samples and burn patients. A total of 78 strains (including 58 clinical and 20 environmental isolates) of the P. aeruginosa were collected from Beasat hospital of Hamadan, west of Iran, and was identified using API 20NE. The disk diffusion method according to the CLSI was applied for determination of the antimicrobial resistance. Moreover, the microtiter plate test was used for the quantification of Biofilm formation. The genomic features of the isolated strains was evaluated using Pulsed Field Gel Electrophoresis (PFGE). We found that 94.8% of clinical and 80% environmental isolates were capable of forming biofilm. The rate of MDR in clinical and environmental isolates was 51.7% and 40%, respectively. A significant relationship was observed between biofilm formation capability and multiple drug resistance (p < 0.05). PFGE typing showed 11 different clusters with two major clusters A with 30 (38.5%) and B with 14 (17.9%) members, containing up to 56.4% of all isolates. There was no relationship between biofilm formation ability and antibiotic resistance patterns with PFGE patterns. According to the results, the clonal spread of environmental P. aeruginosa isolates is associated with clinical isolates, and both environmental and clinical isolates are attributed to a high prevalence of the antibiotic resistance and biofilm formation ability. This study highlighted that the prevention programs should be implemented in the hospital environment to control the spread of P. aeruginosa in burn units.

In this study, the antibacterial activity of disesquiterpene coumarin and sesquiterpene coumarins obtained from Ferula pseudalliacea roots was evaluated by determination of minimum inhibitory concentration using the broth micro-dilution method against seven pathogenic bacterial strains (Staphylococcus aureus ATCC 25,923, vancomycin resistant clinical strain of Enterococcus faecium, Bacillus cereus PTCC 1015, Escherichia coli ATCC 25,922, Pseudomonas aeruginosa PTCC 1430, clinical strain of Klebsiella pneumoniae and a clinical strain of Helicobacter pylori). The overall inhibitory activities of the compounds were higher against Gram positive tested bacteria. Sanandajin and ethyl galbanate demonstrated significant activity against H. pylori strain, as well as S. aureus strain in concentration of 64 μg/ml. Methyl galbanate inhibited vancomycin resistant strain of E. faecium in concentration of 64 μg/ml. The results of the present investigation indicated that disesquiterpene and sesquiterpene coumarins isolated from F. pseudalliacea root extract can be considered as potent antibacterial agents for pharmaceutical and food industries.