Antimicrobial screening of actinobacteria using a modified cross-streak method

Abstract

Out of the 30 actinobacterial cultures screened for antimicrobial activity, 28 cultures were found to produce active products against various pathogenic microorganisms such as Gram-negative, Gram-positive bacteria and yeast, using a modified cross streak method. The modified method helped in easy quantification of results and also in ruling out probable mutual antibiosis. The actinobacterial strains that showed the ability to produce antimicrobial compounds belonged to Streptomyces (53%), Micromonospora (13%) and Actinomadura (10%) genera. Streptomyces sp. strain MMA-5 showed the highest multispecific antibiosis efficiency score value. Broad antibiotic spectrum activity was exhibited by Streptomyces sp. strain MMA-2 and Micromonospora sp. strain MMA-8. The multidrug resistant human pathogenic yeast strain Candida albicans was inhibited by 18 actinobacterial strains.

Antimicrobial potential of actinobacteria isolated from the rhizosphere of the Caatinga biome plant Caesalpinia pyramidalis Tul.

“…As emphasized by Sanchez and Demain (2002), the carbon source may interfere with growth and the yields of bioactive metabolites. The predominance of the genus Streptomyces in soil has also been reported by researchers worldwide (Velho-Pereira and Kamat, 2011;Manimaran et al, 2015). These findings are in accordance with those of our study.…”

Characterization of Actinobacterial Communities from Arauca River Sediments (Colombia) Reveals Antimicrobial Potential Presented in Low Abundant Isolates

“…Cross-streak is a simple and rapid antibacterial method for biological screening in large microbial collections when the goal is to detect strains capable of inhibiting target bacteria growth [ 36 ]. In this case and following a protocol described by Undabarrena [ 16 ], each actinobacterial isolate was inoculated on a quarter of a petri dish with Muller-Hinton agar (MH-Oxoid ® ) in triplicate and was incubated in an Innova ® 42 Incubator at 30 o C for 7 days, providing to each actinobacteria-like isolate enough time to avoid nutrient depletion in the media and produce compounds with antibacterial activity that will diffuse into the agar medium and that can be responsible for growth inhibition in pathogenic bacteria [ 36 ]. After incubation, four pathogenic bacteria (extended-spectrum β-lactamases Klebsiella pneumoniae (ATCC ® 700603 TM ), Staphylococcus aureus -MRSA (ATCC ® BAA¬44 TM ), Enterococcus faecium VRE-(ATCC ® 700221 TM ) and Bacillus subtilis (ATCC ® 21556 TM )) were seeded in 4 cm perpendicular lines.…”

“…In Colombia, hydrographic system of the Orinoquía basin has numerous reports about biodiversity in animals and vegetation, however little is known about its microbial biodiversity [ 25 , 26 ] suggesting that tropical rivers from this habitat can be considered as an unexplored source of actinobacteria with bioactive potential. Strategies to isolate actinobacterial microorganisms from environmental samples are related to the use of physicochemical pretreatments [ 17 , 27 - 35 ], facilitating its observation while removing unwanted microorganisms [ 15 , 36 ]. Screening of microbial collections from environmental samples is a time-consuming and costly process.…”

Bioactivity of a Novel Glycolipid Produced by a Halophilic Buttiauxella sp. and Improving Submerged Fermentation Using a Response Surface Method

“…The samples were dissolved in sterile seawater and then, bacterial strains were cultured on Muller Hinton agar made in seawater. Then, they were screened for antimicrobial activity using cross streak culture method [33] and an isolate with superior antimicrobial activity against E. coli was selected for further detailed examinations. Biochemical, morphological and 16S rRNA sequence analysis were conducted to identify the isolate.…”