Screening for novel antimicrobial agents produced by thirty - four Qatari strains of Streptomyces against multi-antibiotic resistant pathogens

Abstract EN

The antimicrobial a activity produced by 34 Qatari strains of Streptomyces against multi-antibiotic resistant (MAR) pathogens were investigated.

The mean value of the general-antibiotic activity rate (GAAR) was 66.8 % and the range was 40-95 % with maximum value against Staphylococcus aurous QMR1, S.

epidermis's ATCC 1228, Escherichia coli QMR4, and E.

coli 8sW1660.

The mean value of the specific-antibiotic activity rate (SAAR) was 70.0% and the range was 45-100 % where the most effective strains were Streptomyces Q30D, Streptomyces Q41A and Streptomyces Q65D.

These 3 strains showed a 100 % inhibition for all the tested bacterial and fungal strains.

In contrast to the 9 control antibiotics to which pathogens were resistant, the mean value of the inhibition zones of the antimicrobial agents produced by the Qatari Streptomyces reached 21.5 mm with the range of 10-32 mm.

The present data represent novel antimicrobial activity in contrast to the other circumstances where much of the commercial antibiotics either show a narrow spectrum inhibition or are ineffective against the MAR pathogens under hospital and community conditions.