scholarly journals INFLUENCE OF BACTERIAL DIVERSITY AND INTERSPECIES INTERACTIONS ON DRINKING WATER-ASSOCIATED BIOFILMS OF YЕRSINIA ЕNTEROCOLITICA

2018 ◽  
pp. 47-54
Author(s):  
Zvezdimira Tsvetanova ◽  
Hristo Najdenski
Keyword(s):  
Drinking Water ◽  
Biofilm Formation ◽  
Synergetic Effect ◽  
Inhibitory Effect ◽  
Bacterial Biofilm ◽  
Bacterial Isolates ◽  
Interspecies Interactions ◽  
Bacterial Strains ◽  
Enteropathogenic Yersinia ◽  
Individual Partner

The capability of the enteropathogenic Yersinia enterocolitica 8081 bio/serotype 1B/O:8 to form binary and multi-species biofilms with defined bacterial strains was studied. The interspecies interactions in the binary biofilms of the enteropathogen with three bacterial isolates from drinking water and water-associated biofilms were assessed. The effect of each individual partner strain for the Y. enterocolitica involvement in the four-species bacterial biofilm was evaluated by excluding one by one the isolates from the sessile community. It was found out that Y. enterocolitica and the tested bacterial strains interact each other in the binary biofilm formation. Moreover, the Y. enterocolitica involvement in the biofilms depends on the partner strain. In the multi-species biofilms, a synergetic effect of one of the bacterial partner strains on the Y. enterocolitica attachment was detected in contrast to the weak inhibitory effect of another one.

scholarly journals Inhibitory effect of Newtonia extracts and myricetin-3-o-rhamnoside (myricitrin) on bacterial biofilm formation

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Katlego E. Motlhatlego ◽  
Muna Ali Abdalla ◽  
Carmen M. Leonard ◽  
Jacobus N. Eloff ◽  
Lyndy J. McGaw
Keyword(s):  
Antibacterial Activity ◽  
Biofilm Formation ◽  
Fungal Infections ◽  
Synergistic Effects ◽  
Inhibitory Effect ◽  
Bacterial Biofilm ◽  
Hot Water ◽  
Bacterial Strains ◽  
Leaf Extracts ◽  
Natural Treatment

Abstract Background Diarrhoea is a major health issue in both humans and animals and may be caused by bacterial, viral and fungal infections. Previous studies highlighted excellent activity of Newtonia buchananii and N. hildebrandtii leaf extracts against bacterial and fungal organisms related to diarrhoea-causing pathogens. The aim of this study was to isolate the compound(s) responsible for antimicrobial activity and to investigate efficacy of the extracts and purified compound against bacterial biofilms. Methods The acetone extract of N. buchananii leaf powder was separated by solvent-solvent partitioning into eight fractions, followed by bioassay-guided fractionation for isolation of antimicrobial compounds. Antibacterial activity testing was performed using a broth microdilution assay. The cytotoxicity was evaluated against Vero cells using a colorimetric MTT assay. A crystal violet method was employed to test the inhibitory effect of acetone, methanol: dichloromethane and water (cold and hot) extracts of N. buchananii and N. hildebrandtii leaves and the purified compound on biofilm formation of Pseudomonas aeruginosa, Escherichia coli, Salmonella Typhimurium, Enterococcus faecalis, Staphylococcus aureus and Bacillus cereus. Results Myricetin-3-o-rhamnoside (myricitrin) was isolated for the first time from N. buchananii. Myricitrin was active against B. cereus, E. coli and S. aureus (MIC = 62.5 μg/ml in all cases). Additionally, myricitrin had relatively low cytotoxicity with IC50 = 104 μg/ml. Extracts of both plant species had stronger biofilm inhibitory activity against Gram-positive than Gram-negative bacteria. The most sensitive bacterial strains were E. faecalis and S. aureus. The cold and hot water leaf extracts of N. buchananii had antibacterial activity and were relatively non-cytotoxic with selectivity index values of 1.98–11.44. Conclusions The purified compound, myricitrin, contributed to the activity of N. buchananii but it is likely that synergistic effects play a role in the antibacterial and antibiofilm efficacy of the plant extract. The cold and hot water leaf extracts of N. buchananii may be developed as potential antibacterial and antibiofilm agents in the natural treatment of gastrointestinal disorders including diarrhoea in both human and veterinary medicine.

scholarly journals Searching for Antagonistic Activity of Bacterial Isolates Derived from Food Processing Environments on Some Food-Borne Pathogenic Bacteria

2020 ◽  
Vol 49 (4) ◽  
pp. 415-423
Author(s):  
B. Baráti-Deák ◽  
Cs. Mohácsi-Farkas ◽  
Á. Belák
Keyword(s):  
Escherichia Coli ◽  
Food Processing ◽  
Pathogenic Bacteria ◽  
Inhibitory Effect ◽  
Antagonistic Activity ◽  
Bacterial Isolates ◽  
Bacterial Strains ◽  
Food Borne ◽  
Time Period ◽  
Growth Decline

Bacterial strains with inhibitory effect on Salmonella Hartford, Listeria monocytogenes, Yersinia enterocolitica, and Escherichia coli, respectively, were isolated. Out of the 64 bacteria originated from food processing environments, 20 could inhibit at least one of the tested pathogens, and it was proved that growth decline of the pathogenic bacteria was more remarkable by co-culturing than by using cell-free supernatants of the isolates. Seven different genera (Pseudomonas, Bacillus, Paenibacillus, Macrococcus, Staphylococcus, Serratia, and Rothia) reduced the pathogens’ growth during the time period of analysis, and the strongest inhibitory effect was observed after 24 h between 15 and 30 °C. Sensitivity of the tested human pathogenic bacteria against the inhibitory strains was distinct, as Y. enterocolitica could be inhibited by numerous isolates, while S. Hartford proved to be the most resistant. Our results reveal that the isolated bacteria or their excreted metabolites could hinder pathogen growth when used in sufficient quantities.

scholarly journals The Interaction of N-Acetylcysteine and Serum Transferrin Promotes Bacterial Biofilm Formation

2018 ◽  
Vol 45 (4) ◽  
pp. 1399-1409 ◽  
Author(s):  
Supeng Yin ◽  
Bei Jiang ◽  
Guangtao Huang ◽  
Yulong Zhang ◽  
Bo You ◽  
...  
Keyword(s):  
Human Serum ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Serum Proteins ◽  
Venous Catheter ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Bacterial Strains

Background/Aims: N-acetylcysteine (NAC) is a novel and promising agent with activity against bacterial biofilms. Human serum also inhibits biofilm formation by some bacteria. We tested whether the combination of NAC and human serum offers greater anti-biofilm activity than either agent alone. Methods: Microtiter plate assays and confocal laser scanning microscopy were used to evaluate bacterial biofilm formation in the presence of NAC and human serum. qPCR was used to examine expression of selected biofilm-associated genes. Extracellular matrix (ECM) was observed by transmission electron microscopy. The antioxidants GSH or ascorbic acid were used to replace NAC, and human transferrin, lactoferrin, or bovine serum albumin were used to replace serum proteins in biofilm formation assays. A rat central venous catheter model was developed to evaluate the effect of NAC on biofilm formation in vivo. Results: NAC and serum together increased biofilm formation by seven different bacterial strains. In Staphylococcus aureus, expression of genes for some global regulators and for genes in the ica-dependent pathway increased markedly. In Pseudomonas aeruginosa, transcription of las, the PQS quorum sensing (QS) systems, and the two-component system GacS/GacA increased significantly. ECM production by S. aureus and P. aeruginosa was also enhanced. The potentiation of biofilm formation is due mainly to interaction between NAC and transferrin. Intravenous administration of NAC increased colonization by S. aureus and P. aeruginosa on implanted catheters. Conclusions: NAC used intravenously or in the presence of blood increases bacterial biofilm formation rather than inhibits it.

scholarly journals Tetracycline Induces the Formation of Biofilm of Bacteria from Different Phases of Wastewater Treatment

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 989
Author(s):  
Tereza Stachurová ◽  
Kateřina Malachová ◽  
Jaroslav Semerád ◽  
Meta Sterniša ◽  
Zuzana Rybková ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Relative Abundance ◽  
Resistance Genes ◽  
Biofilm Formation ◽  
Treatment Plant ◽  
Bacterial Biofilm ◽  
Resistant Bacteria ◽  
Bacterial Strains ◽  
Wastewater Treatment Process ◽  
Sedimentation Tank

The study monitored the effect of tetracycline on bacterial biofilm formation and compared biofilm formation by resistant bacterial strains in different phases of the wastewater treatment process in wastewater treatment plant (WWTP). The crystal violet staining method was used to evaluate the biofilm formation. Biofilm-related bacterial properties were characterized by hydrophobicity, autoaggregation and motility tests. The relative abundance of tetracycline resistance genes (tetW, tetM, tetO, tetA and tetB) in wastewaters were subsequently quantified using qPCR. The results show that the isolates from the nitrification tank produce biofilm with up to 10 times greater intensity relative to the isolates from the sedimentation tank. In isolates of Aeromonas sp. from the nitrification tank, increased biofilm production in the occurrence of tetracycline from a concentration of 0.03125 µg/mL was observed. The tetW gene showed the highest relative abundance out of all the tested genes. From the sampling points, its abundance was the highest in the sedimentation tank of the WWTP. Based on these results, it can be assumed that resistant bacteria are able to form a biofilm and sub-inhibitory tetracycline concentrations induce biofilm formation. WWTPs thus represent a reservoir of antibiotic resistance genes and contribute to the spread of resistance in the natural environment.

scholarly journals Influence of First-Line Antibiotics on the Antibacterial Activities of Acetone Stem Bark Extract ofAcacia mearnsiiDe Wild. against Drug-Resistant Bacterial Isolates

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Olufunmiso O. Olajuyigbe ◽  
Roger M. Coopoosamy
Keyword(s):  
Synergistic Effects ◽  
Stem Bark ◽  
Antibacterial Activities ◽  
Inhibitory Effect ◽  
Drug Combinations ◽  
Acetone Extract ◽  
Bark Extract ◽  
Bacterial Isolates ◽  
Bacterial Strains ◽  
Agar Diffusion

Background.This study was aimed at evaluating the antibacterial activity of the acetone extract ofA. mearnsiiand its interactions with antibiotics against some resistant bacterial strains.Methods.The antibacterial susceptibility testing was determined by agar diffusion and macrobroth dilution methods while the checkerboard method was used for the determination of synergy between the antibiotics and the extract.Results.The results showed that the susceptibility of the different bacterial isolates was concentration dependent for the extract and the different antibiotics. With the exception ofS. marcescens, the inhibition zones of the extract produced by 20 mg/mL ranged between 18 and 32 mm. While metronidazole did not inhibit any of the bacterial isolates, all the antibiotics and their combinations, except for ciprofloxacin and its combination, did not inhibitEnterococcus faecalis. The antibacterial combinations were more of being antagonistic than of being synergistic in the agar diffusion assay. From the macrobroth dilution, the extract and the antibiotics exerted a varied degree of inhibitory effect on the test organisms. The MIC values of the acetone extract which are in mg/mL are lower than those of the different antibiotics which are inμg/mL. From the checkerboard assay, the antibacterial combinations showed varied degrees of interactions including synergism, additive, indifference, and antagonism interactions. While antagonistic and additive interactions were 14.44%, indifference interaction was 22.22% and synergistic interaction was 37.78% of the antibacterial combinations against the test isolates. While the additivity/indifference interactions indicated no interactions, the antagonistic interaction may be considered as a negative interaction that could result in toxicity and suboptimal bioactivity.Conclusion.The synergistic effects of the herbal-drug combinations may be harnessed for the discovery and development of more rational evidence-based drug combinations with optimized efficiency in the prevention of multidrug resistance and therapy of multifactorial diseases.

Novel bacterial strains for the removal of microcystins from drinking water

2011 ◽  
Vol 63 (6) ◽  
pp. 1137-1142 ◽  
Author(s):  
L. A. Lawton ◽  
A. Welgamage ◽  
P. M. Manage ◽  
C. Edwards
Keyword(s):  
Drinking Water ◽  
Cost Effective ◽  
Health Impact ◽  
Effective Solution ◽  
Bacterial Isolates ◽  
Bacterial Strains ◽  
Successful Isolation ◽  
The World ◽  
Water Treatments ◽  
Significant Health

Microcystins (MC) and nodularin (NOD) are common contaminants of drinking water around the world and due to their significant health impact it is important to explore suitable approaches for their removal. Unfortunately, these toxins are not always removed by conventional water treatments. One of the most exciting areas that hold promise for a successful and cost effective solution is bioremediation of microcystins. Recent work resulted in successful isolation and characterisation of 10 novel bacterial strains (Rhodococcus sp., Arthrobacter spp. and Brevibacterium sp.) capable of metabolizing microcystin-LR (MC-LR) in a Biolog MT2 assay. The work presented here aims to further investigate and evaluate the metabolism and the degradation of multiple microcystins (MC-LR, MC-LF, MC-LY, MC-LW and MC-RR) and nodularin by the bacterial isolates. A total of five bacterial isolates representing the three genera were evaluated using Biolog MT2 assay with a range of MCs where they all demonstrated an overall metabolism on all MCs and NOD. Subsequently, the results were confirmed by observing the degradation of the range of toxins in a separate batch experiment.

Multi-stage assessment of biofilm growth by drinking water bacteria on polymeric pipe materials

2020 ◽  
Author(s):  
Olga Sójka ◽  
Patrick van Rijn ◽  
Henny van der Mei ◽  
Maria Cristina Gagliano
Keyword(s):  
Drinking Water ◽  
Biofilm Formation ◽  
Distribution Systems ◽  
Pipe Material ◽  
Bacterial Strains ◽  
Drinking Water Contamination ◽  
Multi Stage ◽  
Biofilm Development ◽  
Pipe Materials ◽  
Mechanical Cleaning

<p><strong>Introduction</strong></p> <p>The presence of biofilms in drinking water distribution systems (DWDS) leads to a number of issues, i.e. secondary (biological) drinking water contamination, pipe damage and increased flow resistance. Among other operational factors, the selection of pipe material plays an important role in biofilm development. Up to now, the studies that have investigated this correlation provide contradictory results in terms of which material might be the most advantageous in the DWDS biofilm control strategy. Hence, to understand the influence of pipe material on biofilm formation, we focused on developing a standardized methodology that allows a multi-stage assessment of biofilm development on real pipe materials.</p> <p><strong>Results</strong></p> <p>Development of the methodology consisted of three steps: 1) material coupon sterilization, 2) biofilm cultivation and 3) biofilm analysis, using  transparent polyvinyl chloride (PVC) as a study material. For the coupon sterilization, methods utilizing immersion in different disinfectant solutions with and without pre-cleaning by rubbing the coupons in a surfactant solution. The results showed that mechanical cleaning before washing  is crucial and without it, reproducible sterilization was difficult to achieve. Biofilm formation on the PVC coupons was performed in a 6-well plate assay (24, 48 and 72 h; under agitation) using DWDS biofilm strains (<em>Sphingomonas spp</em>. and <em>Pseudomonas extremorientalis</em>) and <em>Pseudomonas aeruginosa</em> as a positive control. Bacterial fitness and ability to secrete EPS and form biofilms on the PVC surfaces were tested by monitoring optical density (OD600 nm), chemical oxygen demand (COD) and protein concentration. The formed biofilm and the morphology of attached bacteria were visualized using crystal violet staining (that allow qualitative (bright field microscopy) and quantitative (OD at 570 nm) evaluation), by scanning electron microscopy (SEM) and DNA staining (4′,6-diamidino-2-phenylindole; DAPI) with fluorescence microscopy. Combination of those techniques gave a complete overview of patterns involved in biofilm development by selected drinking water bacterial strains in presence of a PVC surface. The developed methodology was also applied  for the analysis of bacterial growth on real-grade pipe materials, such as PVC and polyethylene (PE), to understand their role in biofilm formation.</p> <p><strong>Conclusions</strong></p> <p>Implementation of various analytical and microscopic techniques is important in understanding mechanisms behind biofilm development in DWDS and the influence of pipe material in the process. The proposed approach allows the observation of biofilm formation in time, but also of the typical bacterial morphology of attached cells. In this study it was shown that to obtain reproducible results, it is crucial to select an appropriate sterilization technique and the influence of mechanical cleaning cannot be ignored in preparation of polymeric surfaces.</p>

scholarly journals Adhesion and biofilm inhibiting properties of Chinese Herbal Formula SanHuang decoction against antibiotic resistant staphylococcal strains

2020 ◽  
Author(s):  
Shaoe Zhang ◽  
Peizhao Wang ◽  
Xiaotao Shi ◽  
Honglue Tan
Keyword(s):  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Titanium Surface ◽  
Inhibitory Effect ◽  
Bacterial Biofilm ◽  
Control Group ◽  
Plate Method ◽  
Antibiotic Resistant ◽  
Methicillin Resistant ◽  
Chinese Herbal

Abstract Clinical study has shown that external socking and washing with the Chinese herbal SanHuang decoction (SH) can control the orthopedic-biofilm related infections. However, the antibiofilm activities of SH in vitro have not been investigated. The aim of the current study was to explore the effect of SH on adhesion and biofilm formation of antibiotic-resistant staphylococci on titanium surface, and to explore its probable mechanistic effects on staphylococcal strains. Biofilm-forming ATCC 35984 (methicillin-resistant Staphylococcus epidermidis, MRSE) and ATCC 43300 (methicillin-resistant Staphylococcus aureus, MRSA) strains were used in this study. The minimum inhibitory concentrations (MICs) of SH and vancomycin against planktonic bacterial strains were determined by the broth microdilution method. Different sub-MIC of SH with TSB (Tryptic soy broth) were used as the basis for experimental grouping (SH group). TSB culture medium alone (TSB group) or TSB containing vancomycin (vancomycin group) incubated with bacteria were considered as the negative or positive control group, respectively. The inhibitory effect of different treatment on bacterial adhesion and biofilm formation were observed by the spread plate method, CV (crystal violet) staining, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Real time PCR analysis was performed to determine the effect of SH on the expression levels of ica AD and ica R gene in ATCC 35984 during the biofilm formation. The strains were found to be susceptible to SH decoction with MIC and MBC values of 38.75 mg/ml and 77.5 mg/ml, respectively. The MIC values for vancomycin was 2.5 μg/ml. SH treatment with 1 MIC and 1/2 MIC could inhibit the bacteria adhesion on the titanium surface, showing only scattered bacterial adhesion from SEM. CLSM showed that SH with 1 MIC and 1/2 MIC could also inhibit the bacterial biofilm formation. The quantitative results of the spread plate method and CV staining showed that there was significant differences between the SH groups (P < 0.05). Further, with an increase in SH concentration, the inhibitory effect became more obvious at different culture time points, when compared with TSB control group (P < 0.05). Among the groups, vancomycin had the strongest inhibitory effect on bacterial adhesion and biofilm formation (P < 0.01). Meanwhile, with an increase in SH concentration, the expression levels of ica A and ica D decreased, and the expression of ica R increased correspondingly (P < 0.05). In conclusions, a certain concentration of SH can inhibit the adhesion and biofilm formation of antibiotic-resistant Staphylococcal strains on the titanium surface, but the effect was not as good as vancomycin. Its probable mechanistic activity may be through the inhibition of polysaccharide intercellular adhesin synthesis by down-regulating the expression of ica AD gene, thus inhibiting bacterial biofilm formation.

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