Antagonistic Potentiality of Actinomycete-Derived Extract with Anti-Biofilm, Antioxidant, and Cytotoxic Capabilities as a Natural Combating Strategy for Multidrug-Resistant ESKAPE Pathogens

Abstract

The global increase in multidrug-resistant (MDR) bacteria has inspired researchers to develop new strategies to overcome this problem. In this study, 23 morphologically different, soil-isolated actinomycete cultures were screened for their antibacterial ability against MDR isolates of ESKAPE pathogens. Among them, isolate BOGE18 exhibited a broad antibacterial spectrum, so it was selected and identified based on cultural, morphological, physiological, and biochemical characteristics. Chemotaxonomic analysis was also performed together with nucleotide sequencing of the 16S rRNA gene, which showed this strain to have identity with Streptomyces lienomycini . The ethyl acetate extract of the cell-free filtrate (CFF) of strain BOGE18 was evaluated for its antibacterial spectrum, and the minimum inhibitory concentration (MIC) ranged from 62.5 to 250 μg/ml. The recorded results from the in vitro anti-biofilm microtiter assay and confocal laser scanning microscopy (CLSM) of sub-MIC concentrations revealed a significant reduction in biofilm formation in a concentration-dependent manner. The extract also displayed significant scavenging activity, reaching 91.61 ± 4.1% and 85.06 ± 3.14% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), respectively. A promising cytotoxic ability against breast (MCF-7) and hepatocellular (HePG2) cancer cell lines was obtained from the extract with IC 50 values of 47.15 ± 13.10 and 122.69 ± 9.12 μg/ml, respectively. Moreover, based on gas chromatography-mass spectrometry (GC-MS) analysis, nine known compounds were detected in the BOGE18 extract, suggesting their contribution to the multitude of biological activities recorded in this study. Overall, Streptomyces lienomycini BOGE18-derived extract is a good candidate for use in a natural combating strategy to prevent bacterial infection, especially by MDR pathogens.

Antibacterial and antibiofilm activities from soil Streptomyces spp. isolated from Muna Island, Indonesia against multidrug-resistant clinical isolates.

“…Interestingly, we recorded that the lowest antibacterial MIC value which categorized as very active was found on the APM-21 extract against MRSA (78 µg/mL) (Table 4). This result was lower than that previous study derived from S. lienomycini BOGE18 extract (isolated from Egypt) with an MIC value of 250 µg/mL against similar MDR S. aureus strain WS12 clinical isolates [24]. Based on this report, our potential isolate APM-21 has stronger antibacterial activity as shown by lower MIC value.…”

<i>Nocardiopsis synnemataformans</i> NBRM9, an extremophilic actinomycete producing extremozyme cellulase, using lignocellulosic agro-wastes and its biotechnological applications

“…Infections caused by these ESKAPE pathogens are the leading causes of morbidity and mortality around the world [69] ; therefore, the search for natural anti-biofilm agents against such pathogens is of a great importance. Actinomycetes are a rich source of bioactive metabolites with diverse pharmacological and medicinal activities, including anti-biofilm effects [40] , [70] . The use of microbial-derived cellulases as an alternative approach to combat biofilms has already been reported for various microbial sources, such as bacterial cellulase from Bacillus subtilis strain Fatma/1, which showed 84.61% anti-biofilm activity against Pseudomonas aeruginosa [71] , and fungal cellulase (combined with amylase and protease) from Penicillium janthinellum EU2D-21, which showed 88.76%, 87.42%, 85.5%, and 79.72% anti-biofilm activities against the bacterial species Pseudomonas aeruginosa , Staphylococcus aureus , Escherichia coli , and Salmonella enterica , respectively [72] .…”

“…The anti-biofilm activity of the PPC was evaluated against four multidrug-resistant (MDR), biofilm-forming gram-positive ( Enterococcus faecium TS7 and Staphylococcus aureus WS12) and gram-negative ( Acinetobacter baumannii SC6 and Pseudomonas aeruginosa UC22) test strains [40] using 96-well flat-bottomed polystyrene microtiter plates according to the modified method of Kamali et al [5] . Briefly, individual wells of a sterile microtiter plate were filled with 90 µL of MHB medium and inoculated with 10 µL of an overnight bacterial suspension (1 × 10 5 CFU/mL).…”

Effect of germanium oxide on the structural aspects and bioactivity of bioactive silicate glass

“…The plates were incubated at 37 °C and 5% CO2 atmospheric conditions for 24 h. The cells were incubated with 50 μl well −1 of (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) solution. The absorbance of each well was read at a wavelength of 560 nm using an ELISA reader 45 .…”