Antibiotic resistance of Pseudomonas species isolated from Armenian fish farms
Antibiotic resistance became one of the major problems of human race. Extensive and unrestricted antibiotic usage in aquaculture can bring to development of antimicrobial resistance in water environments which in turn can transfer to humans via horizontal gen transfer or even directly. Therefore, there is urgent need to monitor resistance patterns in aquaculture points. Pseudomonas spp. are widespread in water environments hence they are suitable to use for evaluation of antibiotic resistance. The goal was to investigate occurrence of antibiotic resistance within Pseudomonas spp. in Armenian fish farms. Samples were taken from outlet and inlet water of different ponds of Armenia, as well as from various organs of fish by swabbing method. Identification of isolates was done according to cultural, morphological and biochemical characteristics, as well as by API-20E rapid identification system. Antibiotic susceptibility was evaluated by disk diffusion assay against 16 antibiotics. 24 Pseudomonas strains were isolated which belong to six species: P. anguilliseptica, P. fluorescens, P. stutzeri, P. putida, P. aeruginosa and P. alcaligenes. The obtained data showed that all isolates were resistant to at least three antibiotics. High level resistance was detected toward tetracyclines (tetracycline and oxytetracycline) and chloramphenicol within the strains isolated from fish and outlet water, whereas all strains isolated from inlet water were susceptible to mentioned antibiotics. Almost all strains had multiple antibiotic resistance index above 0.2 with the exception of two strains. Thus, high level antibiotic resistance within Pseudomonas spp. in Armenian fish farms was found.