Screening of actinobacteria for antimicrobial activities by a modified "Cross-Streak" method

Abstract

New molecule discovery from natural sources, such as that of actinobacteria, has proved to be an interesting area in antibiotic research, as most of these antibiotics are difficult to synthesize. Out of 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. 53%, 13% and 10% of tested actinobacterial strains belonging to Streptomyces, Micromonospora and Actinomadura genera, respectively, showed the ability of producing antimicrobial compounds. Streptomyces sp. strain MMA-5 showed the highest percentage 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.

Structural and functional microbial diversity in deadwood respond to decomposition dynamics

“…For bacterial–bacterial interactions, a modified cross‐streak method was used as described by Kamat and Velho‐Pereira (2012) where each strain was tested against one another. Briefly, the bacterial strain tested for inhibitory activity (tester) was single streaked in the centre of the Petri dish and incubated at 25°C for 3–7 days until clear colonies were formed.…”

Isolation, characterization and antibacterial activity of actinomycetes from soils of the Langun-Gobingob Cave Complex in Calbiga, Samar

“…The actinomycete isolates were streaked in a single line across Glucose-Yeast-Extract (GYE) Agar plates. The plates were incubated at 32°C for 5 days in order to allow the bacteria to secrete antibacterial substances into the medium (Kamat and Velho-Pereira 2012). Two Gram-positive and two Gram-negative bacterial species were used as test organisms.…”