A Novel Actinomycete sp. Isolated from Egyptian Soil has $-Lactamase Inhibitor Activity and Belongs to the Streptomyces rochei Phylogenetic Cluster

Many pathogenic bacteria secrete $-lactamase enzymes as a mechanism of defence against $-lactam antibiotics. A new Streptomyces sp., NRC-77, was isolated from an Egyptian soil sample. The NRC-77 strain has biochemical, chemotaxonomic, morphological and physiological properties consistent with classification in the genus Streptomyces, with the nearest species being Streptomyces rochei. Furthermore, a phylogenetic analysis of the 16S rRNA gene sequence and ribosomal database project (RDP Classifier) consistent with conventional taxonomy confirmed that strain NRC-77 was most similar to Streptomyces rochei (99%). Therefore, the name Streptomyces rochei NRC-77 was proposed for this strain. The nucleotide sequence of the 16S rRNA gene has been deposited in GenBank under the ID: HM237347. The active metabolite of this strain (clavulanic acid) was determined by a specific synergistic bioassay and a spectrophotometric assay. The clavulanic acid was detected by TLC and the structure of was confirmed by HPLC. The Streptomyces sp. NRC-77 produced 88 mg/l of clavulanic acid in a specific clavulanic acid production medium.