Inhibition of biofilm bacteria and adherent fungi from marine plankton cultures using an antimicrobial combination

Abstract

The presence of organic matter in plankton cultures will lead to 10-to 1000-fold increases in bacterial density in less than 24 h. The presence of bacteria and fungi can damage cultivated phytoplankton and zooplankton. These microorganisms can also inhibit experiments investigating the role of these microorganisms in the community and in biological and ecological laboratory studies. The aim of this study was thus to evaluate the effect of penicillin ? streptomycin ? neomycin (antibiotics) in combination with nystatin (antifungal) to select an antimicrobial combination for the inhibition of biofilm bacteria and adherent fungi that is effective and also non-toxic to marine phytoplankton and zooplankton. Acartia tonsa was exposed to different antimicrobial treatments and application routes (culture medium, culture food, both) to evaluate the survival and egg and fecal pellet production endpoints. The same treatments were also applied to measure Amphibalanus improvisus survival and settlement and Conticribra weissflogii growth endpoints. We selected the most sensitive experimental organism and exposed it to some novel antimicrobial combinations. To evaluate the inhibition potential, biofilm bacteria and adherent fungi were exposed to the treatments that were safe for the bioindicator species. A tonsa was considered the most sensitive of all tested organisms. The treatment composed of 0.025 g L -1 penicillin G potassium ? 0.08 g L -1 streptomycin sulfate ? 0.04 g L -1neomycin sulfate showed the best results for A. tonsa and C. weissflogii cultures. No differences were observed for A. improvisus between the treatments. A. tonsa survival rates showed no differences from the control at nystatin concentrations up to 0.005 g L -1 in combination with the antibiotics. The biofilm bacterial density decreased up to 94% under this treatment, and fungal growth was prevented. Species of other planktonic groups should also be tested to improve our understanding of the effectiveness of the treatments proposed.

Comparison of techniques for counting prokaryotes in marine planktonic and biofilm samples

“…The unstained treatment showed the best cost-benefit for estimating bacterial densities on biofilm (cells cm -2 ) and free-living (cells mL -1 ) bacterial suspensions for all exposures/ages when compared with the results obtained with the SYTO9, PI, DAPI, AO stains when the samples are obtained from laboratory assays. Unstained samples can be applied in FC analysis without compromising the study (Gant et al 1993, Walberg et al 1996, Ambriz-Aviña et al 2014, because non-prokaryote particles (eukaryotes + detritus) were always a small proportion (<3 %) of the planktonic and biofilm samples, as observed in other studies (Agostini et al 2018a,b, Lopes et al 2018.…”

Effect of antimicrobials, salinity, and contamination by air on bacterial and fungal growth in cyprid cultures of Amphibalanus improvisus

“…This could be that the bacterial community in our treatments restores itself over time, since we only applied the antimicrobials every 24 hr. Agostini et al (), Agostini et al () and Lopes, Agostini, Guimarães, et al, ) verified that the bacterial populations begin its restoration process between 13 and 23 hr after the initial dose.…”

“…The microorganisms in invertebrate cultures can be inhibited or eliminated by the use of antimicrobial agents combined with aseptic techniques (Agostini, Macedo, & Muxagata, ; Agostini, Macedo, & Muxagata, ; Aina et al, ; Eggermont et al, ; Göksan & Gökpınar, ; Howes et al, ; Isidori, Lavorgna, Nardelli, Pascarella, & Parrella, ; Lopes, Agostini, Guimarães, & Muxagata, ; Roberts, Kawamura, & Handley, ; Shaw, Harrison, & Andersen, ; Thomason, Hills, Clare, Neville, & Richardson, ). Nevertheless, these substances cannot be used indiscriminately because in some instances, they may be more toxic to the invertebrate than the microbes (Agostini, ; Agostini et al, ; Fisher & Nelson, ).…”

Studying the Effect of Curcumin on Hep3B Hepatocarcinoma in Molecular and Biology Research Laboratory at An-Najah National University

“…This research was done in Molecular and Biology Research Laboratory (G0021) at An-Najah National University using the Roswell Park Memorial Institute (RPMI) which is a culture media for hepatoma Hep3B [11]. RPMI is supplemented with 1% Antibiotic penicillin-streptomycin for routine culture which affects bacterial inhibition [12], 1% Glutamine for tumor cell proliferation [13], and 10%fetal bovine serum (FBS) which most often used in cell culture media as a supplement [14], because the serum is an illde ned component in cell culture medium in general [15].MTS…”