Open AccessBioprospecting of marine Streptomycetes sp. for its antagonistic activity on MDR Pseudomonas aeruginosa and Acinetobacter baumannii isolates
Author(s) -
Shanthi John,
Ramasamy Balagurunathan
Publication year - 2014
Publication title -
asian pacific journal of tropical disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.208
H-Index - 33
ISSN - 2222-1808
DOI - 10.1016/s2222-1808(14)60458-8
Subject(s) - acinetobacter baumannii , microbiology and biotechnology , pseudomonas aeruginosa , antimicrobial , efflux , streptomyces , antibiotics , multiple drug resistance , biology , minimum inhibitory concentration , chemistry , bacteria , biochemistry , genetics
Objective: To assess the antimicrobial activity of the Actinobacteria bioactive secondary\udmetabolite and characterize the drug resistance mechanisms of Pseudomonas aeruginosa (P.\udaeruginosa) and Acinetobacter baumannii (A. baumannii).\udMethods: Potential marine Actinobacteria were isolated and the crude extract was purified using\udthin layer chromatography, the fractions were tested for antimicrobial activity and phylogeny of\udthe selected strain was analyzed. Isolated pathogenic strains were screened for extended spectrum\udbeta-lactamase, mannan-binding lectin, AmpC production, efflux mechanism and polymerase\udchain reaction. The cephalosporin and carbapenem antibiotics were synergistically tested along\udwith Streptomyces sp. PM49 fraction by combination disc test and double-disc synergy test.\udHeterogeneous susceptibility assay, minimum inhibitory concentration and expression of DnaK\ud(Hsp70) were determined.\udResults: Streptomyces sp. PM49 active fraction of Rfvalue 0.69 showed antimicrobial activity and\udan inhibitory zone of 15 to 7 mm obtained. About 34.1% of P. aeruginosa and 4.8% of A. baumannii\udwere multiple drug resistant. AmpC β-lactamase was found in 12% of A. baumannii, efflux\udmechanism was putatively positive in 8/23 of P. aeruginosa and 3/20 of A. baumannii. Combination\uddisc test and double-disc synergy test with both PM49 compound and antibiotics showed an\udincrease in the inhibitory zone of <3 mm to 4 mm, three P. aeruginosa isolates expressed blaIMP.\udHeteroresistant subcolonies grew at a frequency of 3 ×10-5 to 1 ×10-5. Stress induction analysis\udshowed increase of DnaK during heat shock at 52 °C, the levels of protein doubled after exposure\udto the antibiotics.\udConclusions: Novel unexplored Streptomyces spp. antimicrobial constituents can be developed\udas an inhibitor and can be substituted along with the available antibiotics to combat the drug\udresistant pathogens