Isolation, Screening and Identification of two Streptomyces soil isolates exhibiting strong antimicrobial activities against Extended Spectrum Beta Lactamase (ESBL) producers

Author : Yomna N. Elkholy, Khaled M. Aboshanab, Walid F. Elkhatib, Mohammad M. Aboulwafa, Nadia A. Hassouna

One of the urgently needed antimicrobials is those antagonizing extended-spectrum beta-lactamase (ESBL) producers as they represent an emerging global health threat. Objective: Screening soil bacterial isolates for anti-ESBL activity and identifying the promising isolate(s). Methodology and results: A total number of 173 Streptomyces isolates were recovered from various Egyptian soil samples. All recovered isolates were primarily screened for their antagonistic activity against the reference strain, Klebsiella pneumoniae ATCC 700603 using agar plug method. Thirty putative Streptomyces(s) isolates revealed positive antagonistic activity and were secondarily screened against three clinically pathogenic ESBL producers using agar diffusion method. Of these, two isolates exhibited the highest anti-ESBL activity were selected and identified as S. fulvissimus isolate W2 and S. manipurensis isolate H21 using 16S ribosomal RNA gene sequencing. Their morphologies, antibiotic susceptibilities and antimicrobial spectra were studied. Conclusion: the two selected isolates S. fulvissimus isolate W2 and S. manipurensis isolate H21 can be used for novel drug discovery as they have potential in vitro antagonistic activity against ESBL producers and broad spectrum antimicrobial activities.

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