| Popis: |
Antibiotic resistance is reaching a critical level because only few options are available to treat certain pathogenic bacteria mainly those causing hospital-acquired and community acquired infections, which require new active components of wide spectrum. Streptomyces species have played a critical role as a source of secondary metabolites with diverse biological activities, including antibiotics. The present investigation aimed to study the antibacterial potential of the two Streptomyces sp. (Streptomyces umbrosus M1 and Streptomyces catenulae M6) towards infectious diseases causing bacterial pathogens in comparison with commercial antibiotics. Thirty five isolates from urinary tract infections (UTIs) samples were isolated, out of them, 13 isolates (37.1 %) showed 100% of antibiotic resistance. The inhibitory effects of extracts from two Streptomyces strains (M1 and M6) showed highly antibacterial activity with different range. Isolates with code number (12 and 29) showed high susceptibility towards two extracts especially M6.The Minimum Inhibitory Concentrations (MICs) of the extract M6 against Gram positive bacteria displayed MICs ranged from (12.5- 37.5 µg/ml), isolate no 12 had the lowest MIC (12.5 µg/ml). Whereas Gram negative bacteria had the highest MICs values. They documented the MICs in range (25-100 µg/ml), isolate no 29 had the lowest MIC (25 µg/ml). The highly sensitive isolates to the tested extract which had the lowest MIC were identified as Ochrobactrum grignonense and Enterococcus faecalis using 16srRNA. In addition, the scanning electron microscopic analysis confirmed the inhibitory effect of extract M6 by revealing significant morphological alterations and rupture of the cell membranes of the tested strains. In conclusion: the present work evidenced that the Streptomyces sp. were promising candidate for the treatment of the UTIs pathogens. |
