Antibacterial potential of nudibranch-associated bacteria from Saparua and Nusa Laut Islands, Indonesia

Abstract

Kristiana R, Sibero MT, Farisa MY, Ayuningrum D, Dirgantara D, Hanafi M, Radjasa OK, Sabdono A, Trianto A. 2019. Antibacterial potential of nudibranch-associated bacteria from Saparua and Nusa Laut Islands, Indonesia. Biodiversitas 20: 1811-1819. Infections caused by multidrug-resistant bacteria are the international health issue that triggers the urgency of finding new antibacterial agents. The aim of this study was to obtain the nudibranchs-associated bacteria that have bioactivity against multidrug-resistant bacteria. A total of 13 species of nudibranch were identified based on morphological characterization. Overlay methods were used for the screening of the isolates bioactivity against six pathogenic multidrug-resistant bacteria. The Minimum Inhibition Concentration (MIC) of the crude extract was evaluated against Methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, Bacillus subtilis, Klebsiella pneumonia, Micrococcus luteus, and Extended Spectrum Beta Lactamases E. coli (ESBL) using MTT method. A total of 145 isolates were obtained which eleven of the isolates showed antibacterial activity against the pathogenic bacteria. The MIC te sts showed that the best activity was isolate SM-S-9-15 and SM-N-3-7. The methanolic extract of isolate SM-S-9-15 active to all of the pathogenic bacteria, while the ethyl acetate extract of the isolate SM-N-3-7 active to the E. coli, B. subtilis, K. pneumonia at the concentration of 500 g/mL. According to 16S ribosomal RNA gene sequence-based identification, all active isolates belong to Virgibacillus marismortui, V. dokdonensis, Bacillus kochii, Vibrio algynoliticus, and Pseudoalteromonas piscicida.

Bacterial isolates from bryozoan Pleurocodonellina sp.: Diversity and antimicrobial potential against pathogenic bacteria

“…In this case, the authors discovered compound isatin that isolated from genus Pseudoalteromonas, since their best activities against all indicator organisms, which was similar to our results. Comparable studies of marine bacteria from Indonesia sites also showed strain-specific antibacterial patterns against MDR bacteria, which were isolated from nudibranch (Kristiana et al 2019).…”

Screening of the antifungal potential of nudibranch Chromodoris lineolata associated bacteria against Candida albicans

“…Nudibranch samples were collected in ziplock and stored in the coolbox. Each sample was documented and identified according to Sabdono et al (2021) based on morphological appearance [20,32].…”

“…Bacterial isolation was carried out using the serial dilution method according to Kristiana et al (2019) and Wijaya et al (2020) with several modifications. Crushed sample was diluted to 10 -0 , 10 -1 , and 10 -2 concentrations.…”

“…The bacterial colonies were separated into the MT medium using the streak method and incubated at 36°C. The composition of MT medium was as follows: meat extract 0,1%; yeast extract 0,1%; peptone 0,2%; soluble starch 0,5%; glucose 0,5%; CaCO3 0,1%; NaCl 0,2%; and agar 2% [20][21][22].…”

“…Therefore, another way that can be taken to overcome this obstacle is by using nudibranch-associated bacteria as a source of bioactive compounds. A previous study has reported that the nudibranch-associated bacteria from the genus Pseudoalteromonas showed potential antibacterial activity against methicillin-resistant Staphylococcus aureus [20,21]. Unfortunately, the antifungal potential of nudibranch-associated bacteria is still not widely reported.…”