Evaluation of fos A۳ and simultaneous CTX-M genes among fosfomycin resistance Pseudomonas aeruginosa isolates .

Background and Aim : Respiratory secretions of cystic fibrosis (CF) patients provide an environment to the colonization of opportunistic pathogens. The aim of this study was to evaluate the resistance to fosfomycin and the frequency of fos A۳ in simultaneous to CTX-M gene which is responsible to extended spectrum beta-lactamase (ESBL) production among Pseudomonas aeruginosa isolates from patients with CFMethods : In this study, ۴۰ P.aeruginosa isolates from sputum of patients with cystic fibrosis in Mofid hospital were collected ۲۰۲۰ .All isolates were reconfirmed by standard bacteriologic methods and kept in ۱۰% glycerol +TSB at -۷۰°C.Antimicrobial susceptibility test(AST)was performed by disk diffusion method and resistance to fosfomycin and colistin evaluated by E- test. PCR was used for the abundance of fos A۳ and bla CTX-M genes. Results : Based on the AST, the most resistant was to Amikacin (۵۲.۵%). By E- test, resistant to fosfomycin and colistin was (۵۷/۵%) and (۲.۵%) respectively. The frequency of bla CTX-M and FosA۳ plasmid genes was (۴۲.۵%) and (۶۷.۵%) respectively by PCR. Conclusion : Simultaneous existence of fosA۳ gene (۶۷.۵%) and bla CTX-M (۴۲.۴%) among P. aeruginosa isolates, show the importance of distribution of resistant to other bacteria via plasmidic carrier. So, to decrease the resistance rate, doing AST before any prescription and no arbitrarily consumption of antibiotics is recommended. Also, evaluation of the role of chromosomal genes such as glpT and the role of presumptive mutations in the fosfomycin resistant P. aeruginosa isolates in further studies is mandatory.

کلیدواژه ها:

P. aeruginosa ، bla CTX-M ، fosfomycin ، fosA۳ gene