Isolation of Pseudomonas aeruginosa from Clinical and Environmental Samples and Determination of Biofilm Formation Potential, Susceptibility to Antibiotics and Essential Oils

P. aeruginosa is an opportunistic pathogen responsible for causing nosocomial infections in patients with weakened host defences. The organism is also responsible for causing mastitis in animals. This organism is known to acquire resistance to antibiotics rapidly. The rising tide of antibiotic resistance in microbial pathogens has ignited the quest for novel antimicrobial solutions. The present study was planned to isolate and identify P. aeruginosa from clinical and environmental samples. The study also aimed to determine biofilm forming ability and their susceptibility to various antibiotics. Effectiveness of alternative antimicrobials (essential oils) viz. cinnamon, thyme, oregano and clove was also determined against these strains. A total of 10 P. aeruginosa strains were isolated from 102 samples based on morphological, biochemical and molecular methods. An overall positivity of 9.8% (10/102) was found in isolation. All the isolates were found to be multidrug resistant (100%; 10/10) highlighting the importance to search for alternative antimicrobials. All the strains were found to be biofilm producers however, strains differed in their potential to produce biofilms as determined by crystal violet assay and could be classified as mild, moderate and strong biofilm producers. Essential oils of cinnamon, thyme and oregano were found to be effective against these drug-resistant strains of P. aeruginosa indicating their potential as alternative to antibiotics, however, further work is required to access the applicability of these identified essential oils for clinical, food and environmental applications.