Parabens are emerging contaminants that have been detected in drinking water. Their presence in DW distribution systems (DWDS) can alter bacterial behaviour, characteristics, and structure, which may ...compromise DW disinfection. This work provides insights into the impact of methylparaben (MP) on the tolerance to chlorine disinfection and antibiotics from dual-species biofilms formed by Acinetobacter calcoaceticus and Stenotrophomonas maltophilia isolated from DW and grown on high-density polyethylene (HDPE) and polypropylene (PPL). Results showed that dual-species biofilms grown on PPL were more tolerant to chlorine disinfection, expressing a decrease of over 50 % in logarithmic reduction values of culturable cells in relation to non-exposed biofilms. However, bacterial tolerance to antibiotics was not affected by MP presence. Although MP-exposed dual-species biofilms grown on HDPE and PPL were metabolically more active than non-exposed counterparts, HDPE seems to be the material with lower impact on DW risk management and disinfection, if MP is present. Overall, results suggest that MP presence in DW may compromise chlorine disinfection, and consequently affect DW quality and stability, raising potential public health issues.
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•Methylparaben (MP) compromises drinking water (DW) chlorination.•MP-exposed biofilms grown in PPL seem to be more tolerant to chlorine disinfection.•HDPE is the best choice for DW plumbing material in the presence of MP.•MP-exposed biofilms are metabolically more active than non-exposed counterparts.•Bacteria treated with chlorine in MP presence are more tolerant to disinfection.
•Dual-species (S. aureus-P. aeruginosa) biofilms in CF are difficult to eradicate.•A dual-species model in artificial sputum medium was set up.•Combinations of broad-spectrum antibiotics and phages ...were tested.•Synergy was observed between antibiotics and phages to reduce biofilm biomass.•Synergy on CFU in biofilm was observed only for phages active at low MOI.
Staphylococcus aureus and Pseudomonas aeruginosa co-infections in patients with cystic fibrosis (CF) are associated with disease severity. Their treatment is complicated by biofilm formation in the sticky mucus obstructing the airways. Using a dual species biofilm (P. aeruginosa/S. aureus) formed in artificial sputum medium, we investigated the activity of broad-spectrum antibiotics (meropenem, ceftazidime, ciprofloxacin, tobramycin) combined with a cocktail of two (bacterio)phages (PSP3 and ISP) proven active via spot tests and double agar on P. aeruginosa PAO1 and S. aureus ATCC 25923. At the highest tested concentrations (100 x MIC), antibiotics alone caused a 20-50% reduction in biomass and reduced S. aureus and P. aeruginosa CFU of 2.3 to 2.8 and 2.1 to 3.6 log10, respectively. Phages alone reduced biofilm biomass by 23% and reduced P. aeruginosa CFU of 2.1 log10, but did not affect S. aureus viability. Phages enhanced antibiotic effects on biomass and exhibited additive effects with antibiotics against P. aeruginosa, but not against S. aureus. Following inhibition of bacterial respiration by phages in planktonic cultures rationalized these observations by demonstrating that PSP3 was effective at multiplicities of infection (MOI) as low as 10−4 plaque forming units (PFU)/CFU on P. aeruginosa, but ISP, at higher MOI (> 0.1) against S. aureus. Thus, pre-screening inhibition of bacterial respiration by phages may assist in selecting those showing activity at sufficiently low titers to showcase anti-biofilm activity in this complex but clinically-relevant in vitro model of biofilm.
Aims
Multi‐species biofilms formed by fungi and bacteria are clinically common and confer the commensal micro‐organisms with protection against antimicrobial therapies. Previously, the plant alkaloid ...berberine was reported to show antimicrobial efficacy to eliminate bacterial and fungal biofilms. In this study, the combination of berberine and amphotericin B, an antifungal agent, was evaluated against dual‐species Candida albicans/Staphylococcus aureus biofilms.
Methods and Results
Combinatorial treatment by berberine and amphotericin B significantly reduced the biomass and viability of residing species in biofilms. Moreover, morphological examination revealed hyphal filamentation of C. albicans and coadhesion between C. albicans/S. aureus were considerably impaired by the treatment. These effects coincided with the reduced expression of cell surface components and quorum‐sensing‐related genes in both C. albicans and S. aureus. Additionally, in C. albicans, the core transcription factors for controlling biofilm formation together with a crucial component of dual‐species biofilms were also downregulated.
Conclusions
These results demonstrated synergistic effects of berberine and amphotericin B against C. albicans/S. aureus dual‐species biofilms.
Significance and Impact of the Study
This study confirms the potential of berberine and amphotericin B for treating the C. albicans/S. aureus biofilms related infections and reveals molecular basis for the efficacy of combinatorial treatment.
Aims
This study aims to characterize the biofilm produced by mono‐ and dual‐species of Shewanella baltica and Pseudomonas fluorescens as fish spoilers at the different incubation temperature, and to ...elucidate the interactive behaviour of dual‐species biofilm development.
Methods and Results
The mono‐ and dual‐species biofilm formation and adhesion characteristics of S. baltica and P. fluorescens were evaluated by using crystal violet staining, scanning electron microscopy and confocal laser scanning microscopy. Results showed that P. fluorescens had significantly higher biofilm biomass and polysaccharides production than S. baltica, and two isolates reached the maximum biofilm biomass during the early stationary phase. Lower biomass and polysaccharides in dual‐species biofilms were observed compared to mono‐species of P. fluorescens. Meanwhile, S. baltica and P. fluorescens formed fragile and viscous pellicles with different spatial architectures respectively. In dual‐species pellicle few large microcolonies were dominated by P. fluorescens. Compared to mono‐species of PF07, adherent cell population and biofilm thickness at the developing phase significantly decreased, and biofilm‐forming cycle prolonged in the dual‐species biofilms. Biofilm formation and adhesion of mono‐ and dual‐species at 4 or 15°C were significantly higher than at 30°C during the same phase. The culture supernatant extracts of the two spoilage strains greatly inhibited biofilm development to each other.
Conclusions
Shewanella baltica and P. fluorescens had different biofilm and pellicle characteristics, and the inhibitory development on dual‐species biofilm was associated with the competitive interaction by the two psychrotrophic spoilage bacteria.
Significance and Impact of the Study
This work contributes to a better understanding of interactive behaviour of multispecies biofilm communities by psychrotrophic spoilage bacteria at low temperature, which could contribute to further control contamination of spoilage organism during the preservation and processing of aquatic products.
To mitigate food contamination caused by multi-species biofilms, the inhibitory effect of peptide SF on dual-species biofilms was investigated in the study. Vibrio parahaemolyticus frequently engages ...in intercommunication with other bacteria through the autoinducer-2 (AI-2)/LuxS quorum sensing system, contributing to the biofilm formation. However, the knowledge of quorum sensing inhibitors (QSIs) that target dual-species biofilms involving V. parahaemolyticus has remained limited. Therefore, this study constructed dual-species biofilms of V. parahaemolyticus and Aeromonas sobria, assessed AI-2 activity, and investigated the inhibitory effect of the QSI peptide Ser-Phe (SF) on these biofilms. The results indicated that peptide SF (1 mg/mL) significantly inhibited AI-2 activity, production of extracellular polysaccharides, proteins, DNA, metabolic activity, hydrophobicity, and auto-aggregation of these biofilms. The inhibitory rates to the both dual-species and V. parahaemolyticus mono-species were 44.40% and 47.31% for AI-2 activity, 31.29% and 63.84% for extracellular polysaccharides, 53.64% and 48.61% for extracellular proteins, 55.38% and 52.58% for extracellular DNA, 46.18% and 24.46% for metabolic activity, 67.46% and 50.61% for hydrophobicity, and 44.15% and 51.98% for auto-aggregation. Moreover, scanning electron microscopy revealed the disruption of the structure in dual-species biofilms treated with peptide SF. The qRT-PCR results demonstrated that peptide SF down-regulated the expression of key genes related to quorum sensing (luxS and luxP), flagellum (flaA), virulence factors (toxR), and extracellular polymeric substances (cpsA) in the dual-species. However, peptide SF did not inhibit AI-2 activity or biofilm formation in A. sobria. This study will provide a QSI for controlling multi-species biofilms caused by V. parahaemolyticus.
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•A dual-species biofilm model is constructed.•Peptide SF inhibits dual-species biofilm formation by inhibiting the AI-2/LuxS QS system of Vibrio parahaemolyticus.•Peptide SF down-regulates the expression of related genes in the dual-species biofilms.
Compared to mono-species biofilm, biofilms formed by cross-kingdom pathogens are more refractory to conventional antibiotics, thus complicating clinical treatment and causing significant morbidity. ...Lemongrass essential oil and its bioactive component citral were previously demonstrated to possess strong antimicrobial efficacy against pathogenic bacteria and fungi. However, their effects on polymicrobial biofilms remain to be determined. In this study, the efficacy of lemongrass (
) essential oil and its bioactive part citral against dual-species biofilms formed by
and
species was evaluated
. Biofilm staining and viability test showed both lemongrass essential oil and citral were able to reduce biofilm biomass and cell viability of each species in the biofilm. Microscopic examinations showed these agents interfered with adhesive characteristics of each species and disrupted biofilm matrix through counteracting nucleic acids, proteins and carbohydrates in the biofilm. Moreover, transcriptional analyses indicated citral downregulated hyphal adhesins and virulent factors of
, while also reducing expression of genes involved in quorum sensing, peptidoglycan and fatty acids biosynthesis of
. Taken together, our results demonstrate the potential of lemongrass essential oil and citral as promising agents against polymicrobial biofilms as well as the underlying mechanisms of their activity in this setting.
Objective
To evaluate the antimicrobial effects of a peptide containing novel oral spray GERM CLEAN on dual‐species biofilm formed by Streptococcus mutans and Candida albicans and to investigate ...whether GERM CLEAN inhibits the demineralization procedure of bovine enamel in vitro.
Methods
The antimicrobial effects of GERM CLEAN on dual‐species biofilm were analyzed by initial adherence rate calculation, water‐insoluble exopolysaccharides quantification, total biomass quantification, and colony‐forming units (CFUs) counting. Scanning electron microscopy and confocal laser scanning microscopy were applied to evaluate the impacts of GERM CLEAN on the biofilm structure. Further, the effects of GERM CLEAN on acidogenicity of dual‐species were appraised via glycolytic pH drop analysis and hydroxyapatite dissolution measurement. The percentage of Surface Microhardness Reduction (%SMHR) evaluation, Atomic Force Micrograph (AFM) examination, and Transverse Microradiography (TMR) analysis after pH cycling were used to determine whether GERM CLEAN inhibited the demineralization of bovine enamel.
Results
GERM CLEAN decreased the adherence rate, water‐insoluble EPS production, biofilm formation, and acidogenicity of the dual‐species. Moreover, GERM CLEAN significantly inhibited the demineralization status of bovine enamels.
Conclusion
This peptide containing novel oral spray GERM CLEAN has antimicrobial potential toward the dual‐species. GERM CLEAN can also impede the demineralization procedure of enamel.
Chronic skin wounds represent a major burn both economically and socially.
and
are among the most common colonizers of infected wounds and are prolific biofilm formers. Biofilms are a major problem ...in infections due to their increasingly difficult control and eradication, and tolerance to multiple prescribed drugs. As so, alternative methods are necessary. Bacteriophages (phages) and honey are both seen as a promising approach for biofilm related infections. Phages have specificity toward a bacterial genus, species or even strain, self-replicating nature, and avoid dysbiosis. Honey has gained acknowledgment due to its antibacterial, antioxidant and anti-inflammatory and wound healing properties. In this work, the effect of
and
phages vB_EcoS_CEB_EC3a and vB_PaeP_PAO1-D and chestnut honey, alone and combined, were tested using
(polystyrene) and
(porcine skin) models and against mono and dual-species biofilms of these bacteria. In general, colonization was higher in the porcine skins and the presence of a second microorganism in a consortium of species did not affect the effectiveness of the treatments. The antibacterial effect of combined therapy against dual-species biofilms led to bacterial reductions that were greater for biofilms formed on polystyrene than on skin. Monospecies biofilms of
were better destroyed with phages and honey than
monospecies biofilms. Overall, the combined phage-honey formulations resulted in higher efficacies possibly due to honey's capacity to damage the bacterial cell membrane and also to its ability to penetrate the biofilm matrix, promoting and enhancing the subsequent phage infection.
Most living organisms require zinc for survival; however, excessive amounts of this trace element can be toxic. Therefore, the frequent fluctuations of salivary zinc, caused by the low physiological ...level and the frequent introduction of exogenous zinc ions, present a serious challenge for bacteria colonizing the oral cavity. Streptococcus mutans is considered one of the main bacterial pathobiont in dental caries. Here, we verified the role of a P‐type ATPase ZccE as the main zinc‐exporting transporter in S. mutans and delineated the effects of zinc toxification caused by zccE deletion in the physiology of this bacterium. The deletion of the gene zccE severely impaired the ability of S. mutans to grow under high zinc stress conditions. Intracellular metal quantification using inductively coupled plasma optical emission spectrometer revealed that the zccE mutant exhibited approximately two times higher zinc accumulation than the wild type when grown in the presence of a subinhibitory zinc concentration. Biofilm formation analysis revealed less single‐strain biofilm formation and competitive weakness in the dual‐species biofilm formed with Streptococcus sanguinis for zccE mutant under high zinc stress. The quantitive reverse transcription polymerase chain reaction test revealed decreased expressions of gtfB, gtfC, and nlmC in the mutant strain under excessive zinc treatment. Collectively, these findings suggest that ZccE plays an important role in the zinc detoxification of S. mutans and that zinc is a growth‐limiting factor for S. mutans within the dental biofilm.
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