Endotracheal tubes coated with a broad-spectrum antibacterial ceragenin reduce bacterial biofilm in an in vitro bench top model

Author(s):  
María Consuelo Latorre ◽  
María Jesús Pérez-Granda ◽  
Paul B Savage ◽  
Beatriz Alonso ◽  
Pablo Martín-Rabadán ◽  
...  

Abstract Background Ventilator-associated pneumonia is one of the most common nosocomial infections, caused mainly by bacterial/fungal biofilm. Therefore, it is necessary to develop preventive strategies to avoid biofilm formation based on new compounds. Objectives We performed an in vitro study to compare the efficacy of endotracheal tubes (ETTs) coated with the ceragenin CSA-131 and that of uncoated ETTs against the biofilm of clinical strains of Pseudomonas aeruginosa (PA), Escherichia coli (EC) and Staphylococcus aureus (SA). Methods We applied an in vitro bench top model using coated and uncoated ETTs that were treated with three different clinical strains of PA, EC and SA for 5 days. After exposure to biofilm, ETTs were analysed for cfu count by culture of sonicate and total number of cells by confocal laser scanning microscopy. Results The median (IQR) cfu/mL counts of PA, EC and SA in coated and uncoated ETTs were, respectively, as follows: 1.00 × 101 (0.0–3.3 × 102) versus 3.32 × 109 (6.6 × 108–3.8 × 109), P < 0.001; 0.0 (0.0–5.4 × 103) versus 1.32 × 106 (2.3 × 103–5.0 × 107), P < 0.001; and 8.1 × 105 (8.5 × 101–1.4 × 109) versus 2.7 × 108 (8.6 × 106–1.6 × 1011), P = 0.058. The median (IQR) total number of cells of PA, EC and SA in coated and non-coated ETTs were, respectively, as follows: 11.0 [5.5–not applicable (NA)] versus 87.9 (60.5–NA), P = 0.05; 9.1 (6.7–NA) versus 62.6 (42.0–NA), P = 0.05; and 97.7 (94.6–NA) versus 187.3 (43.9–NA), P = 0.827. Conclusions We demonstrated significantly reduced biofilm formation in coated ETTs. However, the difference for SA was not statistically significant. Future clinical studies are needed to support our findings.

2010 ◽  
Vol 59 (10) ◽  
pp. 1225-1234 ◽  
Author(s):  
H. M. H. N. Bandara ◽  
O. L. T. Lam ◽  
R. M. Watt ◽  
L. J. Jin ◽  
L. P. Samaranayake

The objective of this study was to evaluate the effect of the bacterial endotoxin LPS on Candida biofilm formation in vitro. The effect of the LPS of Pseudomonas aeruginosa, Klebsiella pneumoniae, Serratia marcescens and Salmonella typhimurium on six different species of Candida, comprising Candida albicans ATCC 90028, Candida glabrata ATCC 90030, Candida krusei ATCC 6258, Candida tropicalis ATCC 13803, Candida parapsilosis ATCC 22019 and Candida dubliniensis MYA 646, was studied using a standard biofilm assay. The metabolic activity of in vitro Candida biofilms treated with LPS at 90 min, 24 h and 48 h was quantified by XTT reduction assay. Viable biofilm-forming cells were qualitatively analysed using confocal laser scanning microscopy (CLSM), while scanning electron microscopy (SEM) was employed to visualize the biofilm structure. Initially, adhesion of C. albicans was significantly stimulated by Pseudomonas and Klebsiella LPS. A significant inhibition of Candida adhesion was noted for the following combinations: C. glabrata with Pseudomonas LPS, C. tropicalis with Serratia LPS, and C. glabrata, C. parapsilosis or C. dubliniensis with Salmonella LPS (P<0.05). After 24 h of incubation, a significant stimulation of initial colonization was noted for the following combinations: C. albicans/C. glabrata with Klebsiella LPS, C. glabrata/C. tropicalis/C. krusei with Salmonella LPS. In contrast, a significant inhibition of biofilm formation was observed in C. glabrata/C. dubliniensis/C. krusei with Pseudomonas LPS, C. krusei with Serratia LPS, C. dubliniensis with Klebsiella LPS and C. parapsilosis/C. dubliniensis /C. krusei with Salmonella LPS (P<0.05). On further incubation for 48 h, a significant enhancement of biofilm maturation was noted for the following combinations: C. glabrata/C. tropicalis with Serratia LPS, C. dubliniensis with Klebsiella LPS and C. glabrata with Salmonella LPS, and a significant retardation was noted for C. parapsilosis/C. dubliniensis/C. krusei with Pseudomonas LPS, C. tropicalis with Serratia LPS, C. glabrata/C. parapsilosis/C. dubliniensis with Klebsiella LPS and C. dubliniensis with Salmonella LPS (P<0.05). These findings were confirmed by SEM and CLSM analyses. In general, the inhibition of the biofilm development of LPS-treated Candida spp. was accompanied by a scanty architecture with a reduced numbers of cells compared with the profuse and densely colonized control biofilms. These data are indicative that bacterial LPSs modulate in vitro Candida biofilm formation in a species-specific and time-dependent manner. The clinical and the biological relevance of these findings have yet to be explored.


2018 ◽  
Vol 45 (4) ◽  
pp. 1399-1409 ◽  
Author(s):  
Supeng Yin ◽  
Bei Jiang ◽  
Guangtao Huang ◽  
Yulong Zhang ◽  
Bo You ◽  
...  

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.


2006 ◽  
Vol 72 (4) ◽  
pp. 2864-2875 ◽  
Author(s):  
Cordula Lembke ◽  
Andreas Podbielski ◽  
Carlos Hidalgo-Grass ◽  
Ludwig Jonas ◽  
Emanuel Hanski ◽  
...  

ABSTRACT Streptococcus pyogenes (group A streptococcus [GAS]) is a frequent cause of purulent infections in humans. As potentially important aspects of its pathogenicity, GAS was recently shown to aggregate, form intratissue microcolonies, and potentially participate in multispecies biofilms. In this study, we show that GAS in fact forms monospecies biofilms in vitro, and we analyze the basic parameters of S. pyogenes in vitro biofilm formation, using Streptococcus epidermidis as a biofilm-positive control. Of nine clinically important serotype strains, M2, M6, M14, and M18 were found to significantly adhere to coated and uncoated polystyrene surfaces. Fibronectin and collagen types I and IV best supported primary adherence of serotype M2 and M18 strains, respectively, whereas serotype M6 and M14 strains strongly bound to uncoated polystyrene surfaces. Absorption measurements of safranin staining, as well as electron scanning and confocal laser scanning microscopy, documented that primary adherence led to subsequent formation of three-dimensional biofilm structures consisting of up to 46 bacterial layers. Of note, GAS isolates belonging to the same serotype were found to be very heterogeneous in their biofilm-forming behavior. Biofilm formation was equally efficient under static and continuous flow conditions and consisted of the classical three steps, including partial disintegration after long-term incubation. Activity of the SilC signaling peptide as a component of a putative quorum-sensing system was found to influence the biofilm structure and density of serotype M14 and M18 strains. Based on the presented methods and results, standardized analyses of GAS biofilms and their impact on GAS pathogenicity are now feasible.


2008 ◽  
Vol 57 (12) ◽  
pp. 1466-1472 ◽  
Author(s):  
Helena Bujdáková ◽  
Ema Paulovičová ◽  
Silvia Borecká-Melkusová ◽  
Juraj Gašperík ◽  
Soňa Kucharíková ◽  
...  

The Candida antigen CR3-RP (complement receptor 3-related protein) is supposed to be a ‘mimicry’ protein because of its ability to bind antibody directed against the α subunit of the mammalian CR3 (CD11b/CD18). This study aimed to (i) investigate the specific humoral isotypic response to immunization with CR3-RP in vivo in a rabbit animal model, and (ii) determine the role of CR3-RP in the adherence of Candida albicans in vitro using the model systems of buccal epithelial cells (BECs) and biofilm formation. The synthetic C. albicans peptide DINGGGATLPQ corresponding to 11 amino-acids of the CR3-RP sequence DINGGGATLPQALXQITGVIT, determined by N-terminal sequencing, was used for immunization of rabbits to obtain polyclonal anti-CR3-PR serum and for subsequent characterization of the humoral isotypic response of rabbits. A significant increase of IgG, IgA and IgM anti-CR3-RP specific antibodies was observed after the third (P<0.01) and the fourth (P<0.001) immunization doses. The elevation of IgA levels suggested peptide immunomodulation of the IgA1 subclass, presumably in coincidence with Candida epithelial adherence. Blocking CR3-RP with polyclonal anti-CR3-RP serum reduced the ability of Candida to adhere to BECs, in comparison with the control, by up to 35 % (P<0.001), and reduced biofilm formation by 28 % (P<0.001), including changes in biofilm thickness and integrity detected by confocal laser scanning microscopy. These properties of CR3-RP suggest that it has potential for future vaccine development.


2018 ◽  
Vol 20 (4) ◽  
pp. 238
Author(s):  
Júlia Bazaga Ferreira ◽  
Gabriella Rodovalho Paiva ◽  
Vinícius Rangel Geraldo-Martins ◽  
Juliana Jendiroba Faraoni ◽  
Regina Guenka Palma Dibb ◽  
...  

O objetivo deste trabalho in vitro foi avaliar a influência de diferentes agentes remineralizantes no tratamento de lesões erosivas em esmalte. Foram confeccionados espécimes de 4mmx4mm e 3 mm de espessura a partir da superfície vestibular de incisivos bovinos (n=10) e divididos aleatoriamente em 4 grupos. G1=aplicação do dentifrício remineralizante, G2= aplicação do agente potencializador remineralizante, G3= dentifrício remineralizante + agente potencializador remineralizante, G4=aplicação de verniz fluoretado (controle positivo), G5=nenhum tratamento (controle negativo). Os espécimes foram imersos em refrigerante durante um período de 10 dias. A rugosidade superficial foi analisada por meio de microscopia confocal de varredura a laser. Os dados foram analisados quanto à homogeneidade (Levene’s) e normalidade (Kolmogorov- Smirnov). Foram realizados testes paramétricos com análise de variância a dois critérios: fator tempo e fator tratamento, e pós-teste de Tukey para diferenciação das médias. Todos os testes estatísticos tiveram nível de significância de 5% (α=0,05). Os resultados obtidos mostraram diferenças estatisticamente significantes, demonstrando a redução da rugosidade da superfície do esmalte logo após o primeiro tratamento (G3) e para os demais grupos (G1, G2 e G4) somente após o segundo tratamento. Concluiu-se que a utilização de dentifrício composto por silicato de cálcio e fosfato de sódio influenciou na rugosidade do esmalte erodido do dente bovino.Palavras-chave: Dentifrícios. Erosão Dentária. Esmalte Dentário.Abstract The objective of this in vitro study was to evaluate the influence of different remineralizing agents in the treatment of enamel erosive lesions. Specimens of 4mmx4mm and 3mm thickness were made from the buccal surface of bovine incisors (n=10) and randomly divided into 4 groups. G1 = application of the remineralizing dentifrice, G2 = application of the remineralizing agent, G3 = remineralizing dentifrice + remineralizing agente, G4 = application of fluoride varnish (positive control), G5 = no treatment Specimens were immersed in refrigerant solution during a period of 10 days. The surface roughness was analyzed by means of confocal laser scanning microscopy. The data were analyzed for homogeneity (Levene's) and normality (Kolmogorov-Smirnov). Parametric tests with analysis of variance were performed on two criteria: time factor and treatment factor, and Tukey post-test for differentiation of means. All tests were statistically significant at 5% (α = 0.05). The results showed statistically significant difference, demonstrating the reduction of surface roughness after the first treatment (G3) and the other groups (G1, G2 and G4) only after the second treatment. It was concluded that the use of dentifrice composed of calcium silicate and sodium phosphate influenced the roughness of the eroded tooth enamel of the bovine tooth.Keywords: Dentifrices. Tooth Erosion. Tooth Enamel.


Scanning ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Xiuxiu Hou ◽  
Keyong Yuan ◽  
Zhengwei Huang ◽  
Rui Ma

Objective. To compare the effects of bleaching associated with Er:YAG and Nd:YAG laser on enamel structure and mixed biofilm formation on teeth surfaces. Materials and Methods. Sixty-eight enamel samples were randomly divided into four groups ( n = 17 ), control, Opalescence Boost only, Opalescence Boost plus Er: YAG laser, and Opalescence Boost plus Nd:YAG laser. The structure was observed using SEM after bleaching. Subsequently, the treated enamel samples were also cultured in suspensions of Streptococcus mutans, Streptococcus sanguis, Actinomyces viscosus, and Fusobacterium nucleatum (Fn) for 24 and 48 h. Biofilm formation was quantified by crystal violet staining, and the structure was visualized by confocal laser scanning microscopy. The data were analyzed using the Kruskal-Wallis method. Results. The enamel structure significantly changed after bleaching. There was no obvious difference in the biofilm formation after 24 h; however, after 48 hours, the amount of biofilm increased significantly. Remarkably, the amount was significantly higher on enamel bleached only, however, there was no significant difference between samples bleached with Er:YAG or Nd:YAG laser compared to the control. Conclusions. Bleaching only appeared to markedly promote biofilm formation after 48 h, and the biofilms on samples bleached with Er:YAG or Nd:YAG laser did not change significantly, showing that bleaching with Er:YAG or Nd:YAG laser can be safely applied in clinical practice.


2018 ◽  
Vol 27 (2) ◽  
Author(s):  
Tatit Nurseta ◽  
Yahya Irwanto ◽  
I W.A. Wiyasa ◽  
Rahajeng Rahajeng ◽  
Imelda Imelda ◽  
...  

Background: Several studies have reported that curcumin exerts chemopreventive effects in various type of cancers, through several mechanisms, however, the effect of curcumin on carcinogenesis in patients with hydatidiform mole has not yet been investigated. This study was conducted to evaluate the effect of curcumin on apoptosis, proliferation, and nuclear translocation of endothelial nitricoxide synthase in trophoblast cells induced by estradiol in complete hydatidiform mole (CHM).Methods: In this in vitro study, trophoblast cells were divided into six groups, the control group (trophoblast cells were exposed to 100 pg/mL of 17-β estradiol) and the treatment group (trophoblast cells were exposed to 100 pg/mL of 17-β estradiol in the presence of curcumin with doses: 50, 100, 200, 400, and 800 µM). At the end of study, the cell proliferation was analyzed using MTT assay and apoptosis with TUNEL test in each group thropoblast cell. eNOS translocation was assayed using confocal laser scanning microscopy at the various dose of curcumin.Results: Curcumin at the doses of 200, 400, and 800 µM significantly decreased the proliferation and increased the apoptotic index in curcumin-treated group compared to those in the control group (p<0.05). All doses of curcumin treatment significantly decreased the nuclear eNOS expression compared to that in the control group. The three highest doses of curcumin increased cytoplasmic eNOS expression compared to that in control group.Conclusion: Curcumin inhibits the proliferation and modulates the apoptosis of trophoblast cells induced by estradiol in CHM involvement.


2001 ◽  
Vol 67 (3) ◽  
pp. 1343-1350 ◽  
Author(s):  
M. Guggenheim ◽  
S. Shapiro ◽  
R. Gmür ◽  
B. Guggenheim

ABSTRACT The spatial arrangements and associative behavior ofActinomyces naeslundii, Veillonella dispar, Fusobacterium nucleatum, Streptococcus sobrinus, and Streptococcus oralis strains in an in vitro model of supragingival plaque were determined. Using species-specific fluorescence-labeled antibodies in conjunction with confocal laser scanning microscopy, the volumes and distribution of the five strains were assessed during biofilm formation. The volume-derived cell numbers of each strain correlated well with respective culture data. Between 15 min and 64 h, populations of each strain increased in a manner reminiscent of batch growth. The microcolony morphologies of all members of the consortium and their distributions within the biofilm were characterized, as were interspecies associations. Biofilms formed 15 min after inoculation consisted principally of single nonaggregated cells. All five strains adhered strongly to the saliva-conditioned substratum, and therefore, coadhesion played no role during the initial phase of biofilm formation. This observation does not reflect the results of in vitro coaggregation of the five strains, which depended upon the nature of the suspension medium. While the possibility cannot be excluded that some interspecies associations observed at later stages of biofilm formation were initiated by coadhesion, increase in bacterial numbers appeared to be largely a growth phenomenon regulated by the prevailing cultivation conditions.


Author(s):  
Gabriel Rezende-Pereira ◽  
Julia P Albuquerque ◽  
Monica C Souza ◽  
Barbara A Nogueira ◽  
Marlei G Silva ◽  
...  

Abstract Background Bacterial biofilm on surfaces of mammary implants is a predisposing factor for several outcomes. Since Gram-positive bacteria are potential agents of biomaterial-associated infections (BAIs), their abilities to form biofilm on breast implants should be elucidated. Objectives To evaluate biofilm formation on different mammary prosthesis surfaces by major Gram-positive bacterial pathogens involved in BAIs. Methods We initially evaluated biofilm formation on polystyrene plates with and without fibrinogen or collagen for one reference strain and one clinical isolate of Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus pyogenes. We also tested the ability of clinical isolates to form biofilm on four different implant surfaces: polyurethane foam and smooth, microtextured and standard textured silicone. Biofilm structure and cell viability were observed by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Results All strains showed strong biofilm formation on polystyrene. After fibrinogen or collagen treatment, biofilm formation varied. With fibrinogen, reference strains of S. aureus and S. pyogenes increased biofilm formation (p&lt;0.05). Reference strains of all species and the clinical isolate of S. pyogenes increased biofilm formation after collagen treatment (p&lt;0.05). In general, S. aureus showed higher capacity to produce biofilm. SEM showed biofilm attached to all surfaces tested, with the presence of extracellular polymeric substances and voids. Viable cells were more frequent for E. faecalis and S. pyogenes. Conclusions All species produced biofilm on all prosthesis surfaces and under different conditions. Micrographies indicated thicker bacterial biofilm formation on microtextured and/or standard textured silicone by all species, except E. faecalis.


2010 ◽  
Vol 47 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Krzysztof Rychert ◽  
Thomas Neu

Protozoan impact on bacterial biofilm formationConfocal laser scanning microscopy in combination with digital image analysis was used to assess the impact of protozoa on bacterial colonisation of surfaces. Bacterial biofilms were developed from activated sludge in microscope flow cells and were exposed to the grazing pressure of protozoa. The protozoan community from healthy activated sludge and a culture of flagellateBodo saltanswere used as grazers. Experiments comprised 48-h incubations in 3 treatment variants: bacteria with protozoa, bacteria with protozoa added after some time and bacteria without protozoa. When necessary, the elimination of protozoa from the inoculum was carried out with cycloheximide and NiSO4. Experiments demonstrated that protozoa from healthy activated sludge initially disturbed the biofilm development but later they could stimulate its growth. Similar results could be established in the experiment withBodo saltans(inoculum: 1000 cells/ml), however differences were not statistically significant. The finding that protozoa support biofilm development during specific stages may be relevant for biofilm studies with mixed environmental biofilm communities.


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