scholarly journals R-Thanatin Inhibits Growth and Biofilm Formation of Methicillin-Resistant Staphylococcus epidermidisIn VivoandIn Vitro

2013 ◽  
Vol 57 (10) ◽  
pp. 5045-5052 ◽  
Author(s):  
Zheng Hou ◽  
Fei Da ◽  
Baohui Liu ◽  
Xiaoyan Xue ◽  
Xiuli Xu ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Drug Candidate ◽  
Coagulase Negative Staphylococci ◽  
Methicillin Resistant ◽  
Content Type

ABSTRACTStaphylococcus epidermidisis one of the most frequent causes of device-associated infections, because it is known to cause biofilms that grow on catheters or other surgical implants. The persistent increasing resistance ofS. epidermidisand other coagulase-negative staphylococci (CoNS) has driven the need for newer antibacterial agents with innovative therapeutic strategies. Thanatin is reported to display potent antibiotic activities, especially against extended-spectrum-beta-lactamase-producingEscherichia coli. The present study aimed to investigate whether a shorter derivative peptide (R-thanatin) could be used as a novel antibacterial agent. We found that R-thanatin was highly potentin vitroagainst coagulase-negative staphylococci, such asS. epidermidis,S. haemolyticus, andS. hominis, and inhibited biofilm formation at subinhibitory concentrations. Properties of little toxicity to human red blood cells (hRBCs) and human umbilical vein endothelial cells, a low incidence of resistance, and relatively high stability in plasma were confirmed. Excellentin vivoprotective effects were also observed using a methicillin-resistantS. epidermidis(MRSE)-induced urinary tract infection rat model. Electron microscopy and confocal laser-scanning microscopy analyses suggested that R-thanatin disturbed cell division of MRSE severely, which might be the reason for inhibition of MRSE growth. These findings indicate that R-thanatin is active against the growth and biofilm formation of MRSEin vitroandin vivo. R-thanatin might be considered as a specific drug candidate for treating CoNS infections.

scholarly journals Enhancement of Vancomycin Activity against Biofilms by Using Ultrasound-Targeted Microbubble Destruction

2011 ◽  
Vol 55 (11) ◽  
pp. 5331-5337 ◽  
Author(s):  
Nianan He ◽  
Jian Hu ◽  
Huayong Liu ◽  
Tao Zhu ◽  
Beijian Huang ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Laser Scanning ◽  
Rabbit Model ◽  
Antibiotic Activity ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Content Type ◽  
Implanted Medical Devices

ABSTRACTTreating biofilm infections on implanted medical devices is formidable, even with extensive antibiotic therapy. The aim of this study was to investigate whether ultrasound (US)-targeted microbubble (MB) destruction (UTMD) could enhance vancomycin activity againstStaphylococcus epidermidisRP62A biofilms. Twelve-hour biofilms were treated with vancomycin combined with UTMD. The vancomycin and MB (SonoVue) were used at concentrations of 100 μg/ml and 30% (vol/vol), respectively, in studiesin vitro. After US exposure (0.08 MHz, 1.0 W/cm2, 50% duty cycle, and 10-min duration), the biofilms were cultured at 37°C for another 12 h. The results showed that many micropores were found in biofilms treated with vancomycin combined with UTMD. Biofilm densities (A570values) and the viable counts ofS. epidermidisrecovered from the biofilm were significantly decreased compared with those of any other groups. Furthermore, the highest percentage of dead cells was found, using confocal laser scanning microscopy, in the biofilm treated with vancomycin combined with UTMD. The viable counts of bacteria in biofilms in anin vivorabbit model also confirmed the enhanced effect of vancomycin combined with UTMD. UTMD may have great potential for improving antibiotic activity against biofilm infections.

Vacuoles Induced in Mammalian Cells by Helicobacter Cytotoxin are Acidic Organelles

1990 ◽  
Vol 48 (3) ◽  
pp. 168-169
Author(s):  
M. H. Chestnut ◽  
C. E. Catrenich
Keyword(s):  
Acridine Orange ◽  
Mammalian Cells ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Ulcer Disease ◽  
Gastroduodenal Disease ◽  
H Pylori

Helicobacter pylori is a non-invasive, Gram-negative spiral bacterium first identified in 1983, and subsequently implicated in the pathogenesis of gastroduodenal disease including gastritis and peptic ulcer disease. Cytotoxic activity, manifested by intracytoplasmic vacuolation of mammalian cells in vitro, was identified in 55% of H. pylori strains examined. The vacuoles increase in number and size during extended incubation, resulting in vacuolar and cellular degeneration after 24 h to 48 h. Vacuolation of gastric epithelial cells is also observed in vivo during infection by H. pylori. A high molecular weight, heat labile protein is believed to be responsible for vacuolation and to significantly contribute to the development of gastroduodenal disease in humans. The mechanism by which the cytotoxin exerts its effect is unknown, as is the intracellular origin of the vacuolar membrane and contents. Acridine orange is a membrane-permeant weak base that initially accumulates in low-pH compartments. We have used acridine orange accumulation in conjunction with confocal laser scanning microscopy of toxin-treated cells to begin probing the nature and origin of these vacuoles.

scholarly journals Bacterial lipopolysaccharides variably modulate in vitro biofilm formation of Candida species

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
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Significant Inhibition ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Dependent Manner ◽  
Bacterial Lipopolysaccharides ◽  
Species Specific ◽  
Biofilm Development

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.

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.

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

2021 ◽  
Author(s):  
María Consuelo Latorre ◽  
María Jesús Pérez-Granda ◽  
Paul B Savage ◽  
Beatriz Alonso ◽  
Pablo Martín-Rabadán ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
In Vitro Study ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Endotracheal Tubes ◽  
Clinical Strains ◽  
Number Of Cells

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 &lt; 0.001; 0.0 (0.0–5.4 × 103) versus 1.32 × 106 (2.3 × 103–5.0 × 107), P &lt; 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.

The fate of medial edge epithelial cells during palatal fusion in vitro: an analysis by DiI labelling and confocal microscopy

Development ◽  
1992 ◽  
Vol 114 (2) ◽  
pp. 379-388 ◽  
Author(s):  
M.J. Carette ◽  
M.W. Ferguson
Keyword(s):  
Laser Scanning ◽  
Time Course ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Palatal Fusion ◽  
Morphological Criteria ◽  
Medial Edge ◽  
Mesenchymal Transformation

Fusion of bilateral shelves, to form the definitive mammalian secondary palate, is critically dependent on removal of the medial edge cells that constitute the midline epithelial seam. Conflicting views suggest that programmed apoptotic death or epithelial-mesenchymal transformation of these cells is predominantly involved. Due in part to the potentially ambiguous interpretation of static images and the notable absence of fate mapping studies, the process by which this is achieved has, however, remained mechanistically equivocal. Using an in vitro mouse model, we have selectively labelled palatal epithelia with DiI and examined the fate of medial edge epithelial (MEE) cells during palatal fusion by localisation using a combination of conventional histology and confocal laser scanning microscopy (CLSM). In dynamic studies using CLSM, we have made repetitive observations of the same palatal cultures in time-course investigations. Our results concurred with the established morphological criteria of seam degeneration; however, they provided no evidence of MEE cell death or transformation. Instead we report that MEE cells migrate nasally and orally out of the seam and are recruited into, and constitute, epithelial triangles on both the oral and nasal aspects of the palate. Subsequently these cells become incorporated into the oral and nasal epithelia on the surface of the palate. We hypothesize an alternative method of seam degeneration in vivo which largely conserves the MEE population by recruiting it into the nasal and oral epithelia.

Consequences of topoisomerase II inhibition in early embryogenesis of Drosophila revealed by in vivo confocal laser scanning microscopy

1993 ◽  
Vol 104 (4) ◽  
pp. 1175-1185 ◽  
Author(s):  
P. Buchenau ◽  
H. Saumweber ◽  
D.J. Arndt-Jovin
Keyword(s):  
Confocal Laser Scanning Microscopy ◽  
Laser Scanning ◽  
Topoisomerase Ii ◽  
Metaphase Plate ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Scanning Microscopy ◽  
Confocal Laser

The regulation of DNA topology by topoisomerase II from Drosophila melanogaster has been studied extensively by biochemical methods but little is known about its roles in vivo. We have performed experiments on the inhibition of topoisomerase II in living Drosophila blastoderm embryos. We show that the enzymatic activity can be specifically disrupted by microinjection of antitopoisomerase II antibodies as well as the epipodophyllotoxin VM26, a known inhibitor of topoisomerase II in vitro. By labeling the chromatin of live embryos with tetramethylrhodamine-coupled histones, the effects of inhibition on nuclear morphology and behaviour was followed in vivo using confocal laser scanning microscopy. Both the antibodies and the drug prevented or hindered the segregation of chromatin daughter sets at the anaphase stage of mitosis. In addition, high concentrations of inhibitor interfered with the condensation of chromatin and its proper arrangement into the metaphase plate. The observed effects yielded non-functional nuclei, which were drawn into the inner yolk mass of the embryo. Concurrently, undamaged nuclei surrounding the affected region underwent compensatory division, leading to the restoration of the nuclear population, and thereby demonstrating the regulative capacity of Drosophila blastoderm embryos.

scholarly journals Astrogliosis in an Experimental Model of Hypovitaminosis B12: A Cellular Basis of Neurological Disorders due to Cobalamin Deficiency

Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2261
Author(s):  
Zuzanna Rzepka ◽  
Jakub Rok ◽  
Justyna Kowalska ◽  
Klaudia Banach ◽  
Justyna Magdalena Hermanowicz ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Cobalamin Deficiency ◽  
Confocal Laser ◽  
In Vivo Model ◽  
Cellular Expression ◽  
Wide Range ◽  
Vitro Model

Cobalamin deficiency affects human physiology with sequelae ranging from mild fatigue to severe neuropsychiatric abnormalities. The cellular and molecular aspects of the nervous system disorders associated with hypovitaminosis B12 remain largely unknown. Growing evidence indicates that astrogliosis is an underlying component of a wide range of neuropathologies. Previously, we developed an in vitro model of cobalamin deficiency in normal human astrocytes (NHA) by culturing the cells with c-lactam of hydroxycobalamin (c-lactam OH-Cbl). We revealed a non-apoptotic activation of caspases (3/7, 8, 9) in cobalamin-deficient NHA, which may suggest astrogliosis. The aim of the current study was to experimentally verify this hypothesis. We indicated an increase in the cellular expression of two astrogliosis markers: glial fibrillary acidic protein and vimentin in cobalamin-deficient NHA using Western blot analysis and immunocytochemistry with confocal laser scanning microscopy. In the next step of the study, we revealed c-lactam OH-Cbl as a potential non-toxic vitamin B12 antagonist in an in vivo model using zebrafish embryos. We believe that the presented results will contribute to a better understanding of the cellular mechanism underlying neurologic pathology due to cobalamin deficiency and will serve as a foundation for further studies.

scholarly journals Evaluation of Antibiotics Active against Methicillin-Resistant Staphylococcus aureus Based on Activity in an Established Biofilm

2016 ◽  
Vol 60 (10) ◽  
pp. 5688-5694 ◽  
Author(s):  
Daniel G. Meeker ◽  
Karen E. Beenken ◽  
Weston B. Mills ◽  
Allister J. Loughran ◽  
Horace J. Spencer ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Limit Of Detection ◽  
Relative Activity ◽  
Methicillin Resistant ◽  
Content Type ◽  
Comparable Activity ◽  
Antibiotic Delivery

ABSTRACTWe usedin vitroandin vivomodels of catheter-associated biofilm formation to compare the relative activity of antibiotics effective against methicillin-resistantStaphylococcus aureus(MRSA) in the specific context of an established biofilm. The results demonstrated that, underin vitroconditions, daptomycin and ceftaroline exhibited comparable activity relative to each other and greater activity than vancomycin, telavancin, oritavancin, dalbavancin, or tigecycline. This was true when assessed using established biofilms formed by the USA300 methicillin-resistant strain LAC and the USA200 methicillin-sensitive strain UAMS-1. Oxacillin exhibited greater activity against UAMS-1 than LAC, as would be expected, since LAC is an MRSA strain. However, the activity of oxacillin was less than that of daptomycin and ceftaroline even against UAMS-1. Among the lipoglycopeptides, telavancin exhibited the greatest overall activity. Specifically, telavancin exhibited greater activity than oritavancin or dalbavancin when tested against biofilms formed by LAC and was the only lipoglycopeptide capable of reducing the number of viable bacteria below the limit of detection. With biofilms formed by UAMS-1, telavancin and dalbavancin exhibited comparable activity relative to each other and greater activity than oritavancin. Importantly, ceftaroline was the only antibiotic that exhibited greater activity than vancomycin when testedin vivoin a murine model of catheter-associated biofilm formation. These results emphasize the need to consider antibiotics other than vancomycin, most notably, ceftaroline, for the treatment of biofilm-associatedS. aureusinfections, including by the matrix-based antibiotic delivery methods often employed for local antibiotic delivery in the treatment of these infections.

scholarly journals Characterization of Biofilm Formation by Clinically Relevant Serotypes of Group A Streptococci

2006 ◽  
Vol 72 (4) ◽  
pp. 2864-2875 ◽  
Author(s):  
Cordula Lembke ◽  
Andreas Podbielski ◽  
Carlos Hidalgo-Grass ◽  
Ludwig Jonas ◽  
Emanuel Hanski ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Group A Streptococcus ◽  
Three Dimensional ◽  
Positive Control ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Subsequent Formation ◽  
Group A

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.

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