Isolation and identification of early marine biofilm-forming bacteria on commercial paint surface

Aims@#To investigate early marine biofilm-forming bacterial diversity on immersed antimicrobial-free commercial paint substratum in seawater. @*Methodology and results@#Total ten bacterial strains were successfully isolated and identified by complete 16S rRNA sequencing. The isolates morphological, biochemical properties, biofilm-forming ability, extracellular polymeric substance (EPS) productivity and components were characterised. The morphological and biochemical characterization of the strains showed strains-specific variation. All isolates were strong biofilm producers with four motile strains being both flat-bottom and air-liquid-interface biofilm producers, while other strains were only air-liquid interface biofilm producer. Based on 16S rRNA, three strains were identified as Marinomonas communis, two were Marinomonas sp., while the rest were Alteromonas litorea, Alteromonas sp., Salinimonas lutimaris, Idiomarine baltica and Bacillus niabensis. The amount of EPS that the isolates produced ranged from 1.95 to 2.89 g/L and productivity of EPS was inversely correlated with the cell biomass. Analysis of the extracted EPS using attenuated total reflectance-fourier transform infrared (ATR-FTiR) showed that all isolates EPS contained carbohydrates, nucleic acid, protein, DNA/RNA and lipid. @*Conclusion, significance and impact of study@#Bacterial diversity in early stages of biofilm on the commercial paint surface was dominated by Gram-negative bacteria from Gammaproteobacteria class. Isolates with superior cell growth showed lowest EPS production. This finding was expected to provide knowledge on distribution of different marine bacterial species in the biofilm on paint coated surfaces which may beneficial to formularize a new antibiofilm paint additive.

Characterization of extracellular polymeric substance producing isolates from wastewaters and their antibacterial prospective

Bacteria have the ability of biofilm formation, in which the cells attach to each other within a self-producedmatrix of extracellular polymeric substance (EPS). The aim of the present research work was to isolateEPS-producing bacteria from wastewater. Total 21 bacterial isolates were screened for EPS production basedon mucoid and slimy colonies. Out of 21 isolates, nine efficient isolates were selected for the production ofEPS. These efficient bacterial strains were also checked for their antimicrobial potential against Salmonellasp., Escherichia coli, and Klebsiella sp. The isolates ASA3, H2E7, H2F8, and ASB4 inhibited the growth ofSalmonella sp., E. coli, and Klebsiella sp, while isolate ASB5, H2C6, and H2E9 only showed inhibitory effectsagainst Salmonella sp. The maximum concentration of EPS (i.e., 17.2 g/l) was produced by strain ASB4 within3 days of incubation.

Bacterial biofilms: characteristics and combat strategies / 药学学报

Eighty percent of bacterial infections are related to the formation of bacterial biofilm. Compared with planktonic bacteria, bacterial biofilm is 10-1 000 times more resistant to antibiotics, which is the main cause of current bacterial drug resistance. A comprehensive understanding of the characteristics and resistance mechanisms of bacteria biofilm will help us treat the stubborn infections caused by the bacterial biofilm better and solve the problem of bacterial drug resistance. In this review, the composition and quorum sensing of bacterial biofilm, two major patterns of biofilm formation and drug resistance mechanisms were presented. Furthermore, representative compounds with anti-biofilm activity and compounds synergistic with antibiotics in anti-biofilm actions were introduced. Nano drug delivery strategies used for anti-biofilm in recent years as well as a novel drug delivery system-molecularly imprinted polymer was also introduced.

Analysis of Bacterial Biofilms on a Cochlear Implant Following Methicillin-Resistant Staphylococcus Aureus Infection

To demonstrate biofilm formations on a cochlear implant magnet of a pediatric patient suffering from a methicillin-resistant Staphylococcus aureus (MRSA) infection. The appearance of biofilm colonies was analyzed on different magnet sections. The appearance of MRSA biofilms on the surface of an explanted cochlear implant was analyzed by scanning electron microscopy (SEM), focusing on the pattern of extracellular polymeric substances (EPS) within the biofilms. SEM revealed unique biofilms with a three-dimensional EPS complex and tower-like formations. Biofilm configurations changed from the margin to the center of the magnet. Biofilms were solitary and scattered at the margin; large and plate-like in the center; and stacked in layers, forming towers and water channels, in the middle region. After a MRSA infection, biofilm formations were observed on the surface of a magnet. Bacterial biofilms provide optimal conditions for bacterial growth and antibiotic resistance and can cause intractable infections that lead to device failure.