Poor Antimicrobial Activity of Opium Against Carbapenem-Resistant Pseudomonas aeruginosa Isolates

 Carbapenem-resistant Pseudomonas aeruginosa (P. aeruginosa) has dramatically increased. Thus, finding a new therapeutic option is necessary to fight such isolates.

 This study aimed to explore the influence of opium on carbapenem-resistant and carbapenem-sensitive P. aeruginosa.

 During the study period from December 2018 to March 2019, a total of 20 non-duplicate P. aeruginosa isolates were collected from clinical samples in Shahid Mohammadi and Pediatrics hospitals (teaching hospitals) affiliated to Hormozgan University of Medical Sciences in Bandar Abbas, the South of Iran. The antimicrobial susceptibility pattern was tested by the disc diffusion method according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The influence of opium was tested by broth microdilution and agar disc diffusion methods against P. aeruginosa isolates.

 We studied 20 isolates of P. aeruginosa, of which 30%, 30%, 15%, 10%, 10%, and 5% were collected from wound, urine, discharge, blood, tracheal tube, and other specimens, respectively. According to the antimicrobial susceptibility testing results, the highest and lowest rates of resistance were to ofloxacin and piperacillin, respectively. Unexpectedly, all clinical and standard isolates of P. aeruginosa were resistant to different concentrations of opium.

 Based on our experiments, no antimicrobial effect was found for opium against the tested isolates. Studies of opium need to be continued as it may show some bacteriostatic or bactericide activities in other conditions.