A disturbed balance within the dental biofilm can result in the dominance of cariogenic and periodontopathogenic species and disease development. Due to the failure of pharmacological treatment of ...biofilm infection, a preventive approach to promoting healthy oral microbiota is necessary. This study analyzed the influence of
K12 on the development of a multispecies biofilm composed of
,
and
. Four different materials were used: hydroxyapatite, dentin and two dense polytetrafluoroethylene (d-PTFE) membranes. Total bacteria, individual species and their proportions in the mixed biofilm were quantified. A qualitative analysis of the mixed biofilm was performed using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The results showed that in the presence of
K 12 in the initial stage of biofilm development, the proportion of
was reduced, which resulted in the inhibition of microcolony development and the complex three-dimensional structure of the biofilm. In the mature biofilm, a significantly lower proportion of the periodontopathogenic species
was found in the salivarius biofilm. Our results show that
K 12 can inhibit the growth of pathogens in the dental biofilm and help maintain the physiological balance in the oral microbiome.
Bacterial contamination of the membranes used during guided bone regeneration directly influences the outcome of this procedure. In this study, we analyzed the early stages of bacterial adhesion on ...two commercial dense polytetrafluoroethylene (d-PTFE) membranes in order to identify microstructural features that led to different adhesion strengths. The microstructure was investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR). The surface properties were analyzed by atomic force microscopy (AFM), scanning electron microscopy (SEM), and surface free energy (SFE) measurements. Bacterial properties were determined using the microbial adhesion to solvents (MATS) assay, and bacterial surface free energy (SFE) was measured spectrophotometrically. The adhesion of four species of oral bacteria (
,
,
, and
) was studied on surfaces with or without the artificial saliva coating. The results indicated that the degree of crystallinity (78.6% vs. 34.2%, with average crystallite size 50.54 nm vs. 32.86 nm) is the principal feature promoting the adhesion strength, through lower nanoscale roughness and possibly higher surface stiffness. The spherical crystallites ("warts"), observed on the surface of the highly crystalline sample, were also identified as a contributor. All bacterial species adhered better to a highly crystalline membrane (around 1 log
CFU/mL difference), both with and without artificial saliva coating. Our results show that the changes in polymer microstructure result in different antimicrobial properties even for chemically identical PTFE membranes.
is an environmental bacterium, an opportunistic premise plumbing pathogen that causes the Legionnaires' disease.
presents a serious health hazard in building water systems, due to its high resistance ...to standard water disinfection methods. Our aim was to study the use of photodynamic inactivation (PDI) against
. We investigated and compared the photobactericidal potential of five cationic dyes. We tested toluidine blue (TBO) and methylene blue (MB), and three 3-
-methylpyridylporphyrins, one tetra-cationic and two tri-cationic, one with a short (CH
) and the other with a long (C
H
) alkyl chain, against
in tap water and after irradiation with violet light. All tested dyes demonstrated a certain dark toxicity against
; porphyrins with lower minimal effective concentration (MEC) values than TBO and MB. Nanomolar MEC values, significantly lower than with TBO and MB, were obtained with all three porphyrins in PDI experiments, with amphiphilic porphyrin demonstrating the highest PDI activity. All tested dyes showed increasing PDI with longer irradiation (0-108 J/cm
), especially the two hydrophilic porphyrins. All three porphyrins caused significant changes in cell membrane permeability after irradiation and
, co-cultivated with
after treatment with all three porphyrins and irradiation, did not recover in amoeba. We believe our results indicate the considerable potential of cationic porphyrins as effective anti-
agents.
Pool water must meet certain chemical and microbiological conditions to ensure high water quality and a safe environment for users. A recreational swimming pool treated with a combined disinfection ...method (chlorination and UV radiation) was monitored for 18 months. Selected chemical and microbiological parameters of the indoor freshwater pool were analyzed, and the in vivo presence of Pseudomonas aeruginosa biofilm was assessed and further correlated to the type of disinfection. P. aeruginosa isolated from biofilm was further examined to determine the effects of combined disinfection methods on the formation and destruction of mature biofilm in vitro. The in vitro application of the combined disinfection methods led to the inhibition of planktonic P. aeruginosa biofilm formation (68.9% compared to the control group) and were more effective in the partial destruction of mature biofilm than individual disinfection methods (from 25.4 to 26.3%). The obtained results indicate the better microbiological and chemical quality of pool water when combined disinfection was applied. Our results contribute to developing the optimization of pool water disinfection methods and biofilm control.
Emerging infectious diseases that we are witnessing in the modern age are among the leading public health concerns. They most often occur in the form of epidemics or pandemics, and they have not been ...sufficiently researched. Owing to the current coronavirus disease 2019 (COVID-19) pandemic, the World Health Organization has published various recommendations to prevent the spread of this communicable disease, including a recommendation to wear protective facial masks. Therefore, this study aimed to determine the filtration effectiveness of bacteria, yeasts, and molds on three different commonly and commercially available masks used in children’s educational institutions. In addition, the bacterial content of indoor air bioaerosols was identified. The genera Staphylococcus and Micrococcus were dominant in all samples, whereas bacteria of the genera Bacillus, Acinetobacter, and Corynebacterium were identified at a significantly smaller number. Bacterial, yeast, and mold filtering effectiveness increased from the single-layer cloth mask, which proved to be the least effective, to the surgical mask, to the filtering facepiece type 2 (FFP2) mask. Furthermore, surveys are needed to study the effectiveness of protective measures.
Pseudomonas fluorescens is one of the first colonizers of bacterial biofilm in water systems and a member of opportunistic premise plumbing pathogens (OPPPs). The aim of this study was to examine the ...effect of UV light and sodium hypochlorite on the formation and destruction of mature P. fluorescens biofilm on ceramic tiles. Planktonic bacteria or bacteria in mature biofilm were exposed to UV light (254 nm) for 5, 20 s. and to 0.4 mg/L sodium hypochlorite for 1 min. Mature biofilm was also exposed to increased concentration of sodium hypochlorite of 2 mg/L for 0.5, 1 and 2 h and combined with UV. Prolonged action of sodium hypochlorite and an increase in its concentration in combination with UV gave the best results in the inhibition of biofilm formation after the pre-treatment and destruction of mature biofilm. The effect of hyperchlorination in combination with UV radiation shows better results after a long exposure time, although even after 120 min there was no completely destroyed biofilm. Furthermore, the mechanism of the effect of combined methods should be explored as well as the importance of mechanical cleaning that is crucial in combating bacterial biofilm in swimming pools.
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•A total of 4 different herbal extracts were analyzed against 96 Enterococcus uroisolates.•Phenolic composition, antimicrobial and anti-biofilm activity were determined.•The most of ...Enterococcus faecium isolates were recognized as multiple resistant.•More than 30 % of Enterococcus faecalis isolates have shown moderately biofilm production.•Synergism in antibiosis was detected among two herbal extract combinations.
Antibacterial and antibiofilm efficacy through a synergistic effect of herbal leaf extracts of bearberry (BE), bearberry tea (BTE), parsley (PE), and the strawberry tree (STE) was evaluated to discover an alternative approach to control urinary tract infections caused by Enterococci. UHPLC–DAD MS/MS analysis indicated that herbal extracts were rich in ellagic and gallic acids, catechin, quercetin, and arbutin, which are strong antioxidants. Mostly, Enterococcus faecalis isolates showed resistance only to gentamicin and/or norfloxacin (26.3 %) and moderate biofilm production (31.5 %), while 12 isolates of Enterococcus faecium showed multiple antibiotic resistance. The minimum inhibitory concentration for the majority of isolates was 1.25 mg ml−1 for STE, but 2.5 mg ml−1 for BE and BTE. Although individual extracts gave higher MIC values, for most isolates, a synergistic effect at lower concentrations was achieved, when BE or BTE (0.625 mg ml−1) was combined with STE (0.31 mg ml−1). The BTE extract was shown to have the strongest individual effect on initial adhesiveness and on biofilm formation to all selected isolates, while the synergism of BTE and STE caused significant biofilm inhibition at all concentrations tested. The synergistic effect achieved of the tested extract combinations might be a starting point in the development of alternative products, effective against antibiotic resistant Enterococcus isolates.
Aim
To determine antimicrobial activity of honey against clinical bacterial strains and their respective reference strains.
Methods
Twelve samples of Croatian honey from various botanical origin were ...evaluated for their antimicrobial activity against four clinical antibiotic resistant pathogens and their respective reference strains: Staphylococcus aureus, Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli. Antibacterial susceptibility was checked out by using broth microdilution method and interpreted according to the European Committee for Antimicrobial Susceptibility Testing (EUCAST) recommendations.
Results
Significant differences in the antibacterial activity of tested honey samples were noticed. Fir honeydew honey and Mint honey showed the best antibacterial potential, while the Locust tree honey, Rapeseed honey and Spring pasture honey expressed the weakest antimicrobial activity.
Conclusion
Croatian honey, prominently honeydew honey, has the potential to become an important additive to therapeutic techniques available to a medical practitioner against resistant pathogens, but the exact mechanisms of its activity should be investigated further.
To explore the interaction effects of ciprofloxacin and ampicillin with nickel on the growth of bacteria,
Staphylococcus aureus
strain ATCC 29213,
Enterococcus faecalis
ATCC 29212 and
Escherichia ...coli
ATCC 25922 were used. Minimum inhibitory concentrations (MICs) were determined for nickel, ciprofloxacin and ampicillin, and the checkerboard method was used to assess their cumulative effects on bacterial growth. The interactions between the metal and antibiotics were assessed by the fractional inhibitory concentration (FIC). The MICs for ciprofloxacin and ampicillin were 0.31 and 1 mg/L for
E. faecalis
, 0.62 and 1 mg/L for
S. aureus
and 0.005 and 2.5 for
E. coli
, respectively. The MIC for nickel was 1000 mg/L for all bacteria. The FIC results for ciprofloxacin and nickel demonstrated an antagonistic effect of the two agents on the growth of
E. coli
and
E. faecalis
and an additive effect on
S. aureus
. The FICs for ampicillin and nickel demonstrated a synergistic effect on the growth of
E. faecalis
and
E. coli
. Different interactions of metals and antibiotics were observed depending on the bacteria and the type of antibiotic.
Adhesion of the most common dental biofilm bacteria to alloys used in orthodontics in relation to surface characteristics was analyzed. Streptococcus mutans (S. mutans), Streptococcus oralis (S. ...oralis), Veillonella parvula (V. parvula), and Aggregatibacter actinomycetemcomitans (A. actynomicetemcomitans) were incubated for 4 h with nickel-titanium (NiTi) and stainless-steel (SS) wires. The surface roughness and free energy of the alloys, as well as the hydrophobicity of the alloys and bacteria, were assessed. NiTi had higher surface free energy and rougher (p<0.001) and more hydrophilic surfaces than SS (p<0.001). The hydrophobic properties of the bacteria decreased in the following order: V. parvula>S. oralis>S. mutans>A. actynomicetemcomitans. Bacterial adhesion generally increased over time, though this pattern was influenced by the type of alloy and the bacteria present (p<0.001). In a multiple linear regression, the principal predictor of adhesion was bacterial hydrophobicity (p<0.001), followed by time (p<0.001); alloy surface characteristics had a low influence.
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