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Andes Pediatrica : Revista Chilena de... Apr 2024Bacteremia is a major cause of morbidity and mortality in patients with cancer and episodes of high-risk febrile neutropenia (HRFN).
UNLABELLED
Bacteremia is a major cause of morbidity and mortality in patients with cancer and episodes of high-risk febrile neutropenia (HRFN).
OBJECTIVE
To identify the frequency of microorganisms isolated from blood cultures (BC) and their antimicrobial resistance (R) profile in children with HRFN, compared with the same data from previous studies of the same group.
METHOD
Prospective, multicenter, epidemiological surveillance study of microorganisms isolated from BC in patients under 18 years of age, from 7 PINDA network hospitals, between 2016 and 2021.
RESULTS
284 episodes of HRFN with positive BC were analyzed out of 1091 enrolled episodes (26%). Median age 7.2 years [3.0-12.3]. The main isolates were gram-negative bacilli (GNB) 49.2%, gram-positive cocci (GPC) 43.8%, and fungi 3.6%. The most frequently isolated microorganisms were viridans group Streptococci (VGS) (25.8%), Escherichia coli (19.8%), Pseudomonas spp. (11.2%), Klebsiella spp. (10.9%), and coagulase negative Staphylococci (CoNS) (10.9%). There was an increase in R to third-generation cephalosporins (p = 0.011) in GNB and to oxacillin in CoNS (p = 0.00), as well as a decrease in R to amikacin in non-fermenting GNB (p = 0.02) and to penicillin in VGS (p = 0.04).
CONCLUSION
VGS is the main agent isolated in BC from pediatric patients with cancer and episodes of HRFN, followed by E. coli, Pseudomonas spp., and Klebsiella spp. Having epidemiological surveillance of microorganisms isolated from BC and their antimicrobial R profile is essential to favor the rational use of antimicrobials.
Topics: Humans; Child; Neoplasms; Prospective Studies; Child, Preschool; Febrile Neutropenia; Chile; Bacteremia; Female; Male; Blood Culture; Anti-Bacterial Agents; Drug Resistance, Bacterial; Microbial Sensitivity Tests; Adolescent; Gram-Negative Bacteria
PubMed: 38801361
DOI: 10.32641/andespediatr.v95i2.5012 -
Acta Odontologica Scandinavica May 2024Toothpastes are widely used to protect oral and teeth health. This study aims to examine the cytotoxic and antimicrobial effects of whitening toothpastes.
OBJECTIVE
Toothpastes are widely used to protect oral and teeth health. This study aims to examine the cytotoxic and antimicrobial effects of whitening toothpastes.
METHODS
In this study, extracts were prepared according to ISO 10993-12:2021 standard (0.2 g/mL) using whitening and conventional toothpastes. The prepared extracts were added to human gingival fibroblast cell lines (HGF-1) in different dilutions (1:1, 1:2, 1:4, 1:8, 1:16, and 1:32) and a cytotoxicity test was performed. Antimicrobial analysis of toothpastes was performed on Streptococcus mutans, Staphylococcus aureus, and Candida albicans using the hole-plate diffusion method. Cell viability and microbial analysis data were examined using two-way analysis of variance (ANOVA) and Tukey post-hoc test (p < 0.05).
RESULTS
Toothpastes with sodium lauryl sulfate (SLS) in their composition showed statistically more toxic effects (p < 0.05). The activated carbon toothpastes without SLS showed over 90% cell viability after dilution. Although the dilution rate of toothpastes containing SLS increased, cell viability remained below 70%. All toothpastes used in the study showed antimicrobial effects on S. mutans, S. aureus, and C. albicans. Toothpaste containing hydrogen peroxide and SLS produced more antibacterial effects than activated carbon, blue covarine, microparticles, and conventional toothpaste.
CONCLUSIONS
SLS-containing toothpastes showed more toxicity on HGF-1 cells. Toothpaste containing hydroxyapatite did not show toxic effects on HGF-1 cells. SLS, sodium lauryl sarcosinate and hydrogen peroxide in toothpastes increase antimicrobial effects.
Topics: Toothpastes; Humans; Candida albicans; Staphylococcus aureus; Streptococcus mutans; Anti-Infective Agents; Cell Survival; Cell Line; In Vitro Techniques; Fibroblasts; Tooth Bleaching Agents
PubMed: 38801222
DOI: 10.2340/aos.v83.40774 -
International Journal of Molecular... May 2024The gene cluster for Type IV pilus (Tfp) biosynthesis is commonly present and highly conserved in . Nevertheless, Tfp-mediated twitching motility is less common among...
The gene cluster for Type IV pilus (Tfp) biosynthesis is commonly present and highly conserved in . Nevertheless, Tfp-mediated twitching motility is less common among strains, and the factors determining twitching activity are not fully understood. Here, we analyzed the functions of three major pilin proteins (PilA1, PilA2, and PilA3) in the assembly and activity of Tfp in motile CGMH010. Using various recombinant deletion strains, we found that Tfp composed of different PilA proteins varied morphologically and functionally. Among the three PilA proteins, PilA1 was most critical in the assembly of twitching-active Tfp, and recombinant strains expressing motility generated more structured biofilms under constant shearing forces compared to the non-motile recombinant strains. Although PilA1 and PilA3 shared 94% identity, PilA3 could not compensate for the loss of PilA1, suggesting that the nature of PilA proteins plays an essential role in twitching activity. The single deletion of individual genes had little effect on the invasion of host endothelia by CGMH010. In contrast, the deletion of all three genes or , encoding the retraction ATPase, abolished Tfp-mediated invasion. Tfp- and PilT-dependent invasion were also detected in the non-motile SK36, and thus, the retraction of Tfp, but not active twitching, was found to be essential for invasion.
Topics: Fimbriae Proteins; Streptococcus sanguis; Fimbriae, Bacterial; Biofilms; Bacterial Proteins
PubMed: 38791440
DOI: 10.3390/ijms25105402 -
Journal of Dentistry Jul 2024Evaluate, in vitro, the effect of incorporating nano-sized sodium trimetaphosphate (TMPnano) and phosphorylated chitosan (Chi-Ph) into resin-modified glass ionomer...
OBJECTIVES
Evaluate, in vitro, the effect of incorporating nano-sized sodium trimetaphosphate (TMPnano) and phosphorylated chitosan (Chi-Ph) into resin-modified glass ionomer cement (RMGIC) used for orthodontic bracket cementation, on mechanical, fluoride release, antimicrobial and cytotoxic properties.
METHODS
RMGIC was combined with Chi-Ph (0.25%/0.5%) and/or TMPnano (14%). The diametral compressive/tensile strength (DCS/TS), surface hardness (SH) and degree of conversion (%DC) were determined. For fluoride (F) release, samples were immersed in des/remineralizing solutions. Antimicrobial/antibiofilm activity was evaluated by the agar diffusion test and biofilm metabolism (XTT). Cytotoxicity in fibroblasts was assessed with the resazurin method.
RESULTS
After 24 h, the RMGIC-14%TMPnano group showed a lower TS value (p < 0.001); after 7 days the RMGIC-14%TMPnano-0.25%Chi-Ph group showed the highest value (p < 0.001). For DCS, the RMGIC group (24 h) showed the highest value (p < 0.001); after 7 days, the highest value was observed for the RMGIC-14%TMPnano-0.25%Chi-Ph (p < 0.001). RMGIC-14%TMPnano, RMGIC-14%TMPnano-0.25%Chi-Ph, RMGIC-14%TMPnano-0.5%Chi-Ph showed higher and similar release of F (p > 0.001). In the SH, the RMGIC-0.25%Chi-Ph; RMGIC-0.5%Chi-Ph; RMGIC-14%TMPnano-0.5%Chi-Ph groups showed similar results after 7 days (p > 0.001). The RMGIC-14%TMPnano-0.25%Chi-Ph group showed a better effect on microbial/antibiofilm growth, and the highest efficacy on cell viability (p < 0.001). After 72 h, only the RMGIC-14%TMPnano-0.25%Chi-Ph group showed cell viability (p < 0.001).
CONCLUSION
The RMGIC-14%TMPnano-0.25%Chi-Ph did not alter the physical-mechanical properties, was not toxic to fibroblasts and reduced the viability and metabolism of S. mutans.
CLINICAL RELEVANCE
The addition of phosphorylated chitosan and organic phosphate to RMGIC could provide an antibiofilm and remineralizing effect on the tooth enamel of orthodontic patients, who are prone to a high cariogenic challenge due to fluctuations in oral pH and progression of carious lesions.
Topics: Chitosan; Anti-Bacterial Agents; Glass Ionomer Cements; Biofilms; Fibroblasts; Materials Testing; Phosphorylation; Fluorides; Hardness; Tensile Strength; Surface Properties; Compressive Strength; Nanoparticles; Resin Cements; Polyphosphates; Dental Cements; Cell Survival; Streptococcus mutans; Animals; Phosphates; Humans; Orthodontic Brackets
PubMed: 38782176
DOI: 10.1016/j.jdent.2024.105073 -
ACS Applied Materials & Interfaces Jun 2024Caries is a destructive condition caused by bacterial infection that affects the hard tissues of the teeth, significantly reducing the quality of life for individuals....
Caries is a destructive condition caused by bacterial infection that affects the hard tissues of the teeth, significantly reducing the quality of life for individuals. Photothermal therapy (PTT) offers a noninvasive and painless treatment for caries, but the use of unsafe laser irradiance limits its application. To address this challenge, we prepared nanoparticles of silver ion-doped Prussian blue (AgPB), which was encased within cationic guar gum (CG) to form the antibacterial PTT hydrogel CG-AgPB with a photothermal conversion efficiency of 34.4%. When exposed to an 808 nm laser at a power density of 0.4 W/cm, the hydrogel readily reached a temperature of over 50 °C in just 3 min, synchronized by the discharge of Ag ions from the interstitial sites of AgPB crystals, resulting in broad-spectrum and synergistic antibacterial activities (>99%) against individual oral pathogens (, , and ) and pathogen-induced biofilms. In vivo, CG-AgPB-mediated PTT demonstrated a capability to profoundly reduce the terminal number of cariogenic bacteria to below 1% in a rat model of caries. Given the outstanding biocompatibility, injectability, and flushability, this CG-AgPB hydrogel may hold promise as a next-generation oral hygiene adjunct for caries management in a clinical setting.
Topics: Silver; Anti-Bacterial Agents; Hydrogels; Dental Caries; Animals; Rats; Ferrocyanides; Photothermal Therapy; Biofilms; Streptococcus mutans; Microbial Sensitivity Tests; Humans; Rats, Sprague-Dawley
PubMed: 38772043
DOI: 10.1021/acsami.4c04302 -
Clinical Oral Investigations May 2024White spot lesions are the most common iatrogenic effect observed during orthodontic treatment. This study aimed to compare the surface characteristics and antibacterial... (Comparative Study)
Comparative Study
Evaluation of the surface characteristics and antibacterial properties of Titanium dioxide nanotube and methacryloyloxyethylphosphorylcholine (MPC) coated orthodontic brackets-a comparative invitro study.
OBJECTIVES
White spot lesions are the most common iatrogenic effect observed during orthodontic treatment. This study aimed to compare the surface characteristics and antibacterial action of uncoated and coated orthodontic brackets.
MATERIALS AND METHODS
Sixty commercially available stainless steel brackets were coated with TiO nanotubes and methacryloyloxyethylphosphorylcholine. The sample was divided into Group 1: uncoated orthodontic brackets, Group 2: Stainless steel brackets with TiO nanotubes coating, Group 3: Stainless steel brackets with methacryloyloxyethylphosphorylcholine coating, and Group 4: Stainless steel brackets with TiO nanotubes combined with methacryloyloxyethylphosphorylcholine coating. Surface characterization was assessed using atomic force microscopy and scanning electron microscopy. Streptococcus mutans was selected to test the antibacterial ability of the orthodontic brackets, total bacterial adhesion and bacterial viability were assessed. The brackets were subjected to scanning electron microscopy to detect the presence of biofilm.
RESULTS
The surface roughness was the greatest in Group 1 and least in Group 2 followed by Group 4 and Group 3 coated brackets. The optical density values were highest in Group 1 and lowest in Group 4. Comparison of colony counts revealed high counts in Group 1 and low counts in Group 4. A positive correlation between surface roughness and colony counts was obtained, however, was not statistically significant.
CONCLUSIONS
The coated orthodontic brackets exhibited less surface roughness than the uncoated orthodontic brackets. Group 4 coated orthodontic brackets showed the best antibacterial properties.
CLINICAL RELEVANCE
Coated orthodontic brackets prevent adhesion of streptococcus mutans and reduces plaque accumulation around the brackets thereby preventing formation of white spot lesions during orthodontic treatment.
Topics: Titanium; Orthodontic Brackets; Phosphorylcholine; Surface Properties; Streptococcus mutans; Anti-Bacterial Agents; Microscopy, Electron, Scanning; Nanotubes; Bacterial Adhesion; Microscopy, Atomic Force; Materials Testing; Stainless Steel; Methacrylates; Biofilms; Coated Materials, Biocompatible
PubMed: 38761310
DOI: 10.1007/s00784-024-05655-w -
Clinical Oral Investigations May 2024To assess the growth of a multispecies biofilm on root canal dentin under different radiotherapy regimens.
OBJECTIVES
To assess the growth of a multispecies biofilm on root canal dentin under different radiotherapy regimens.
MATERIALS AND METHODS
Sixty-three human root dentin cylinders were distributed into six groups. In three groups, no biofilm was formed (n = 3): NoRT) non-irradiated dentin; RT55) 55 Gy; and RT70) 70 Gy. In the other three groups (n = 18), a 21-day multispecies biofilm (Enterococcus faecalis, Streptococcus mutans, and Candida albicans) was formed in the canal: NoRT + Bio) non-irradiated + biofilm; RT55 + Bio) 55 Gy + biofilm; and RT70 + Bio) 70 Gy + biofilm. The biofilm was quantified (CFUs/mL). Biofilm microstructure was assessed under SEM. Microbial penetration into dentinal tubules was assessed under CLSM. For the biofilm biomass and dentin microhardness pre- and after biofilm growth assessments, 45 bovine dentin specimens were distributed into three groups (n = 15): NoRT) non-irradiated + biofilm; RT55 + Bio) 55 Gy + biofilm; and RT70 + Bio) 70 Gy + biofilm.
RESULTS
Irradiated specimens (70 Gy) had higher quantity of microorganisms than non-irradiated (p = .010). There was gradual increase in biofilm biomass from non-irradiated to 55 Gy and 70 Gy (p < .001). Irradiated specimens had greater reduction in microhardness after biofilm growth. Irradiated dentin led to the growth of a more complex and irregular biofilm. There was microbial penetration into the dentinal tubules, regardless of the radiation regimen.
CONCLUSION
Radiotherapy increased the number of microorganisms and biofilm biomass and reduced dentin microhardness. Microbial penetration into dentinal tubules was noticeable.
CLINICAL RELEVANCE
Cumulative and potentially irreversible side effects of radiotherapy affect biofilm growth on root dentin. These changes could compromise the success of endodontic treatment in oncological patients undergoing head and neck radiotherapy.
Topics: Biofilms; Dentin; Humans; Dental Pulp Cavity; Candida albicans; Animals; Enterococcus faecalis; Streptococcus mutans; Cattle; Microscopy, Electron, Scanning; Hardness; Microscopy, Confocal; Radiotherapy Dosage
PubMed: 38761225
DOI: 10.1007/s00784-024-05719-x -
Archives of Oral Biology Aug 2024The aim of this study was to investigate the difference in dental biofilm formation according to substratum direction, using an artificial biofilm model.
OBJECTIVES
The aim of this study was to investigate the difference in dental biofilm formation according to substratum direction, using an artificial biofilm model.
METHODS
A three-species biofilm, consisting of Streptococcus mutans, Streptococcus oralis, and Actinomyces naeslundii, was formed on saliva-coated hydroxyapatite (sHA) discs oriented in three directions: downward (the discs placed in the direction of gravity), vertical (the discs placed parallel to the direction of gravity), and upward (the discs placed in opposite direction of gravity). The biofilms at 22 h and 46 h of age were analyzed using microbiological and biochemical methods, fluorescence-based assays, and scanning electron microscopy to investigate difference in bacterial adhesion, early and mature biofilm formation.
RESULTS
The biofilms formed in the upward direction displayed the most complex structure, with the highest number and biovolume of bacteria, as well as the lowest pH conditions at both time points. The vertical and downward directions, however, had only scattered and small bacterial colonies. In the 22-h-old biofilms, the proportion of S. oralis was similar to, or slightly higher than, that of S. mutans in all directions of substratum surfaces. However, in the 46-h-old biofilms, S. mutans became the dominant bacteria in all directions, especially in the vertical and upward directions.
CONCLUSIONS
The direction of the substratum surface could impact the proportion of bacteria and cariogenic properties of the multi-species biofilm. Biofilms in an upward direction may exhibit a higher cariogenic potential, followed by those in the vertical and downward directions, which could be related to gravity.
Topics: Biofilms; Actinomyces; Streptococcus mutans; Microscopy, Electron, Scanning; Saliva; Streptococcus oralis; Bacterial Adhesion; Durapatite; Humans; Surface Properties; Hydrogen-Ion Concentration
PubMed: 38759390
DOI: 10.1016/j.archoralbio.2024.106002 -
Human Vaccines & Immunotherapeutics Dec 2024Dental caries is a prevalent oral disease that mainly results from . Susceptibility to decreased rapidly after weaning in a well-known rat model. However, owing to the...
Dental caries is a prevalent oral disease that mainly results from . Susceptibility to decreased rapidly after weaning in a well-known rat model. However, owing to the lack of time to establish protective immunity ahead of challenge, the weaning rat model is suboptimal for assessing prophylactic vaccines against infection. In this study, we found that, in adult rats, cultured under air-restricted conditions showed dramatically increased colonization efficacy and accelerated development of dental caries compared with those cultured under air-unrestricted conditions. We propose that cultured under air-restricted conditions can be used to develop an optimal caries model, especially for the evaluation of prophylactic efficacy against . Therefore, we used the anti-caries vaccine, KFD2-rPAc, to reevaluate the protection against the challenge of . In immunized rats, rPAc-specific protective antibodies were robustly elicited by KFD2-rPAc before the challenge. In addition to inhibiting the initial and long-term colonization of , KFD2-rPAc immunization showed an 83% inhibitory efficacy against the development of caries, similar to that previously evaluated in a weaning rat model. These results demonstrate that culturing under air-restricted conditions can promote infection in adult rats, thereby helping establish a rat infection model to evaluate the prophylactic efficacy of vaccines and anti-caries drugs.
Topics: Animals; Dental Caries; Streptococcus mutans; Disease Models, Animal; Rats; Antibodies, Bacterial; Streptococcal Vaccines; Streptococcal Infections; Female; Rats, Sprague-Dawley
PubMed: 38757492
DOI: 10.1080/21645515.2024.2345943 -
Archives of Oral Biology Aug 2024There have been reports on the effects of epigallocatechin gallate (EGCG) against Streptococcus mutans viability and acidogenesis. However, the effects of EGCG on the...
INTRODUCTION
There have been reports on the effects of epigallocatechin gallate (EGCG) against Streptococcus mutans viability and acidogenesis. However, the effects of EGCG on the virulence of S. mutans biofilm development have yet to be fully investigated using validated cariogenic biofilm models.
OBJECTIVE
Thus, this study aimed to evaluate the effects of EGCG on S. mutans biofilm virulence using a validated cariogenic model and clinically relevant treatment regimens, twice a day for 1.5 min.
METHODS
Effects of EGCG on bacterial viability, polyssacharide synthesis and biofilm acidogenesis were evaluated. The morphology and 3D structure of the biofilms were evaluated by scanning electron (SEM) and confocal laser scanning microscopy, respectively.
RESULTS
No significant change in S. mutans viability or culture medium pH were observed when comparing EGCG-treated and NaCl-treated biofilms. EGCG significantly reduced the accumulation of soluble and insoluble polysaccharides, resulting in the formation of a biofilm with interspaced exopolysaccharide-microcolony complexes unevenly distributed on enamel. The SEM images of the biofilm treated with EGCG depict multilayers of cells arranged in short chains of microorganisms adhered to an unstructured matrix, which is not continuous and does not enmesh or protect the microorganisms entirely. Importantly, confocal images demonstrated that treatment with EGCG affected the 3D structure and organization of S. mutans biofilm, which presented a biofilm matrix more confined to the location of the microcolonies.
CONCLUSION
In conclusion, EGCG lowered the virulence of S. mutans matrix-rich biofilm by reducing the synthesis of biofilm matrix components, altering the biofilm matrix structure, organization, and distribution.
Topics: Biofilms; Streptococcus mutans; Catechin; Virulence; Microscopy, Confocal; Microscopy, Electron, Scanning; Dental Caries; Hydrogen-Ion Concentration; Microbial Viability; Polysaccharides, Bacterial; Dental Enamel
PubMed: 38749386
DOI: 10.1016/j.archoralbio.2024.105990