Screening for antimicrobial activity among bacteria isolated from the Amazon Basin

Abstract

Bacteria producing antimicrobial activity were identified among 86 isolates from aquatic environments of Brazilian Amazon Basin. Antimicrobial activity against at least one indicator strain was detected for 59 isolates (68.6%). Inhibitory activity was mostly against Gram-positive bacteria, such as Listeria monocytogenes and Bacillus cereus. The antimicrobial substances produced by 19 strains that showed higher inhibitory activity were partially characterized. These antimicrobial substances showed thermal resistance for up to 100°C and partial resistance to proteolytic treatment. Some antimicrobials were partially resistant to pronase E at 2 mg ml -1 or to treatment with trichloroacetic acid. Detection of antimicrobial activity on polyacrylamide gels revealed that the molecular weight of the compounds was lower than 14 kDa. Several strains showed antibacterial activity, which in some cases appear to be related to antimicrobial peptides. The potential of these microorganisms to produce useful antimicrobial compounds is great and must be better explored.

In vitro activity, extraction, separation and structure elucidation of antibiotic produced by Streptomyces anulatus NEAE-94 active against multidrug-resistant Staphylococcus aureus

“…Different strains of S. aureus can cause serious infections including boils and pimples, wound infections, pneumonia, osteomyelitis, septicemia, food intoxication and toxic shock syndrome. The rising frequency of antibiotic resistance among pathogenic S. aureus has created an urgent need to discover novel antibiotics with a broad spectrum of activity against resistant organisms [4].…”

Purification and partial characterization of an antimicrobial peptide produced by Bacillus sp. strain P45, a bacterium from the Amazon basin fish Piaractus mesopotamicus

“…We recently reported the production of antimicrobial activity by several strains of Bacillus isolated from aquatic environments of the Brazilian Amazon basin Motta et al, 2004). The aim of this study was to purify and to determine some properties of an antimicrobial peptide produced by a novel Bacillus sp.…”

“…The organism was isolated from the intestinal contents of the teleost fish Jaraqui (Piaractus mesopotamicus) of the Amazon basin, at central Amazonia, near Manaus, Brazil (Motta et al, 2004). Phenotypic characterization was carried out as described elsewhere (Clauss and Berkeley, 1986;MacFaddin, 2000).…”

Antimycobacterial activity of a Brevibacillus Laterosporus strain isolated from a moroccan soil

“…The agar wells were filled with 100 µl of the prepared filtrates (20). The zones of inhibition were analyzed after 72 h of incubation at 37°C.…”