Multidrug resistance and phylogenetic analyses of Pseudomonas aeruginosa based on the 16S rRNA gene of isolates recovered from clinical samples and their susceptibility to silver-nanoparticle.

Background: Pseudomonas aeruginosa is a highly antimicrobial-resistant pathogen with a very narrow range of effective antibacterial agents. Therefore, finding alternative compounds is highly required, such as silver nanoparticles (AgNPs).

Aim: The current study was conducted to identify the multidrug resistance (MDR) profile and perform a phylogenetic analysis on P. aeruginosa isolates recovered from clinical samples (human, cows, cats, and fish) and to study their susceptibility to AgNPs.

Methods: 40 samples were subjected to conventional cultivation and biochemical analyses to identify P. aeruginosa. Moreover, these isolates were tested for their antibiotic resistance profile and their response to AgNPs using disk diffusion methods. PCR and Sanger-based sequencing were performed using the 16S rRNA gene as a target.

Results: The results showed that all isolates were resistant to cefixime and sensitive to meropenem. Conversely, the AgNPs were effective in producing larger zones of inhibition. The PCR revealed amplification of the target, and the sequencing and phylogenetic tree of four isolates revealed close similarity with global human sequences from different regions.

Conclusion: The study reveals the MDR characteristics of P. aeruginosa. The isolates are highly susceptible to silver nanoparticles.