Antimicrobial activity of Streptomyces sp. isolated from the gulf of Aqaba-Jordan and screening for NRPS, PKS-I, and PKS-II genes

Abstract

Forty-nine Streptomyce es isolates were recover red from sed diment samp ples in the g ulf of Aqab a/Jordan. All isolates were teste ed for antimicrobial ac ctivity again nst Gram positive bacte eria, Gram negative bacteria, an d yeast. Tw wenty eight S Streptomyce es isolates w were active a against at lea ast one of th he tested strains. Th e majority o f the isolat tes showed activity aga ainst Gram positive bac cteria: Strep ptomyces aureus (89 9%), Strepto myces epidermidis (64 4%) and Bac cillus Subti ilis (50 %). Lower activ vity was observed t toward Gram negative bacteria wit th only 25% % active ag ainst Pseudo omonas ae ruginosa, whereas on nly 17% were active aga inst the yeas st Candida a albicans. Is olate S34 sho owed best a activity. It produced h heat stable an timicrobial activity at bo oth acidic an nd alkaline pH (5 to 5.5 a and 8 to 9.5). S34 was found to be e related to S treptomyce es rochei. Forty-nine Stre eptomyces isolates were e screened f or genes encoding n non ribosoma l peptide sy ynthetases ( (NRPS) and polyketides synthases ( (PKS; types I and II). NRPS sequ uences were widely dist ributed and detected in 81% of Stre eptomyces i solates. PKS S types I and II were detected in 63.2 and 65 5.3% of isolates, respecttively. Addit ionally, the r relationship between the occurre ences of biosynthetic ge ene sequences (NPRS a and PKS sequences) an nd the prod uction of antimicrobiial activities was determined. The ab bove results reveal that the marine S Streptomyce etes are a promising source of novel and unique products.