Molecular Study of Azithromycin-Resistant P. aeruginosa

The aim of the present study was to investigate the occurrence of azithromycin resistance among P. aeruginosa swabs isolates. Out of 60 pus, burn and wound swabs, 16 (26.6%) P. aeruginosa were isolated. The susceptibilities of the P. aeruginosa isolates to the macrolides azithromycin, chloramphenicol and aminoglycosides streptomycin, gentamicin and kanamycin were evaluated by disc diffusion experiments. The azithromycin was observed to be less resistance with high susceptibilities rate 13 (81.25) as compared to aminoglycosides and chloramphenicol. Partial 23S rDNA gene sequences of 12 isolates demonstrate new single base substitution in the resistant isolates in positions A1807G, C1808A, A1823G and A1819G which confer the azithromycin resistance with low frequency rate 0.9 for each one. As we recommend the azithromycin is the drug of choice in P. aeruginosa treatment, further study is needed to whole 23S rDNA gene in local isolates to identify mutations outside the partial selected region.