We are grateful for the financial support from the Natural Science Foundation of Shaanxi Province (grant number 2021SF-118) and the National Natural Science Foundation of China (grant numbers 81973409, 82204631).

Experimental animals, male BALB/c mice (12-16 g), were purchased from the Laboratory Animal Center, Xi&#39;an Jiaotong University Health Science Center. All the procedures were approved by the Institutional Animal Ethical Committee of Xi&#39;an Jiaotong University with the license number SCXK (Shaanxi) 2021-103.
1. Buffer and equipment preparation
<ol>
	<li>Transfect C. albicans strains with a high-expression plasmid pCaExp.
	<ol>
		<li>Purchase C. albicans (SC5314) from ATCC. Obtain the EGFP high-expression fluorescent strain22 by transfecting C. albicans with a high-expression plasmid pCaExp containing the complete open reading frame of EGFP gene (the plasmid map is shown in Figure 1) and use this for subsequent experiments.</li>
	</ol>
	</li>
	<li>Culture the transfected C. albicans strains.
	<ol>
		<li>Select monoclonal colonies of C. albicans fluorescent strain from the yeast extract peptone dextrose medium (YPD) plate and culture overnight (30 &#176;C and 220 rpm) in 5 mL of YPD liquid medium (YPD + 50 &#181;g/mL carbenicillin).</li>
		<li>Resuspend the C. albicans in normal saline after centrifugation at 400 x g for 5 min at RT.</li>
		<li>Adjust the concentration of C. albicans suspension to 1 x 108 cells/mL by comparing the turbidity to 0.5 McFarland standard.</li>
	</ol>
	</li>
	<li>Prepare the surgical instruments.
	<ol>
		<li>Ensure to autoclave all the surgical instruments (scissors, forceps, hemostatic forceps, needle holders, suture needles) at 121&#176;C for 30 min. Sterile&#160;polyethylene catheters (inner diameter: 0.28 mm; outer diameter: 0.63 mm) are used. 
		NOTE: The catheters used in this study were sterilized with ethylene oxide gas and the packaging was opened in an ultra-clean table exposed to UV for more than 30 min. Prior to implantation in mice, the catheters were immersed in 75% ethanol to prevent contamination.</li>
	</ol>
	</li>
</ol>
2. Establishment of a mouse CRI model
NOTE: The surgical procedure is shown in Figure 2.
<ol>
	<li>Acclimatize 30 BALB/c mice (12-16 g, male) in specific-pathogen-free (SPF) conditions with free access to water and food and 12 h-12 h alternating light and dark cycle.</li>
	<li>Randomly divide 30 BALB/c mice into three groups (n = 10 mice/group): (A) normal control group; (B) catheter group (catheters implanted without C. albicans); (C) Model group (catheters implanted with C. albicans).</li>
	<li>Anesthetize the mice with 1-4% isoflurane and place the mice on an operating table in a prone position. The loss of righting reflex and no response to toe stimulation confirms the successful anesthesia. Remove the hair and sterilize the surgical site with three alternating rounds of iodophor or chlorhexidine and alcohol scrubs.</li>
	<li>Leave the mice in the normal control group without any treatment and provide free access to food and water.</li>
	<li>For the mice in the catheter and model groups, maintain anesthesia at 3% isoflurane. Confirm adequate anesthetic depth by the absence of a response to toe pinch and adjust isoflurane concentration as needed.</li>
	<li>For the mice in the catheter group, intradermally insert a 1 mL sterile syringe needle into the back-depilated area to make a hole. Insert a catheter (about 1 cm in length) into the hole after removing the syringe needle.</li>
	<li>For the mice in the model group, pipette 20 &#181;L of C. albicans suspension onto the back-depilation area to simulate the commensal C. albicans on the skin.</li>
	<li>After the solution gets absorbed by the skin, insert a catheter in the back-depilated area with the same procedures as described in step 2.5.</li>
	<li>Pipette another 20 &#181;L of C. albicans suspension along the catheter to the tissue to simulate C. albicans in the external environment.</li>
	<li>Fix the catheters with tape and gauze and return the mice to cages for feeding. At the end of the treatment, subcutaneously inject the mice with meloxicam (4 mg/kg) as analgesia for three consecutive days. 
	NOTE: After surgery, mice were carefully fed with water and food. The mice were monitored twice a day. Mice were euthanized by an IACUC-approved method if they experienced feeding difficulties, significant weight loss (10-20%), and hypothermia.</li>
</ol>
3. Evaluation of the CRI model
<ol>
	<li>After 3 days, anesthetize the mice with 3% isoflurane and sacrifice them by cervical dislocation. Collect the catheters and skin tissue samples from the back of the mice.</li>
	<li>Observe&#160;C. albicans and biofilms on the catheter by scanning electron microscopy.
	<ol>
		<li>Immerse the catheters into 2.5% glutaraldehyde solution at 4 &#176;C for 48 h. Rinse the catheters with sterile PBS three times.</li>
		<li>Fix the catheters with 1% osmic acid for 3 h and rinse them with sterile PBS three times.</li>
		<li>Dehydrate the cells on the catheters in gradient ethanol solution with ascending concentrations (50%, 70%, 80%, 90%, and 100%, 15 min/gradient).</li>
		<li>Immerse the catheters in tert-butyl alcohol three times (30 min each time).</li>
		<li>Quickly freeze the catheters in liquid nitrogen, and freeze-dry the sample in a freeze-dryer as per the manufacturer&#39;s instructions.</li>
		<li>Sputter-coat the catheter samples with a 10 nm gold by an ion beam deposition.</li>
		<li>Observe the presence of C. albicans and its biofilm on the catheter surface of each group under a scanning electron microscope (under high vacuum, 1.5 kV conditions) and record the images in each group.</li>
	</ol>
	</li>
	<li>Observe C. albicans on the catheter by fluorescence microscopy.
	<ol>
		<li>Immerse the catheters in 4% paraformaldehyde solution for fixation at 4 &#176;C for 48 h.</li>
		<li>Observe the presence of C. albicans and its biofilm on the catheter surface of each group by a fluorescence microscope under 484 nm excitation and record the images in each group. 
		NOTE: The magnification is 400x. The fluorescence of Candida albicans can be observed with excitation at 490 nm and emission at 510 nm.</li>
	</ol>
	</li>
	<li>Observe C. albicans residing in the mouse skin.
	<ol>
		<li>Immerse the dorsal skin tissues of mice into 4% paraformaldehyde solution for fixation at 4 &#176;C for 48 h.</li>
		<li>Dehydrate the dorsal skin tissues in a gradient ethanol solution with ascending concentrations (50%, 70%, 80%, 90%, and 100%, 15 min/gradient).</li>
		<li>Embed the dehydrated dorsal skin tissues in paraffin at 55-60 &#176;C. Pay attention to the temperature to avoid brittle tissues. To remove as many impurities as possible, repeat this step three times (30 min each).</li>
		<li>Section the dorsal skin tissues (thickness = 5 &#181;m) with a microtome.</li>
		<li>Dewax the paraffin sections by immersing the slides in xylene twice for 20 min.</li>
		<li>Rehydrate the sections via eluting with gradient ethanol (absolute ethanol, 90% ethanol, 75% ethanol, water) for 5 min each time.</li>
		<li>Stain the sections with periodic acid by immersing the section in the periodic acid solution for 15 min before washing with running water once and distilled water twice.</li>
		<li>Stain the sections with a chevron staining solution (per the manufacturer&#39;s instructions) for 30 min in the dark and rinse the sections under running water for 5 min.</li>
		<li>Immerse the sections in hematoxylin solution for 3-5 min before washing with running water (2-3 min), differentiated solution (5-10 min), and running water, respectively.</li>
		<li>Immerse the sections in ethanol three times ( 5 min each) and xylene two times ( 5 min each) before sealing the section with neutral gum.</li>
		<li>Observe the images of the specimen with a microscope and analyze the C. albicans residues in mouse skin. 
		NOTE: The magnification is 10x for the eyepiece and 4x or 10x for the objective lens.</li>
	</ol>
	</li>
	<li>Observe the histopathological changes in the dorsal skin tissues.
	<ol>
		<li>Immerse the dorsal skin tissues into 4% paraformaldehyde solution for fixation at 4 &#176;C for 48 h. Dehydrate the dorsal skin tissues in gradient ethanol solution with ascending concentrations (50%, 70%, 80%, 90%, and 100%, 15 min/gradient).</li>
		<li>Embed the dehydrated dorsal skin tissues in paraffin as described in step 3.4.3.</li>
		<li>Section the dorsal skin tissues (thickness = 5 mm) with a microtome.</li>
		<li>Dewax the paraffin sections by immersing the slides in xylene twice for 20 min.</li>
		<li>Rehydrate the sections via eluting with gradient ethanol (absolute ethanol, 90% ethanol, 75% ethanol, water) for 5 min each time.</li>
		<li>Stain the sections with hematoxylin for 4 min before rinsing with tap water to remove float color.</li>
		<li>Differentiate the specimen with 1% hydrochloric acid-ethanol solution before rinsing the slides with running water.</li>
		<li>Immerse the specimen in 85% and 95% ethanol for 5 min, and stain them with eosin solution for 3 min.</li>
		<li>Dehydrate the specimen by immersing them in gradient ethanol (70%, 90%, 95%, and 100%) and xylene for 2 min each.</li>
		<li>Seal the specimen with neutral resin.</li>
		<li>Observe the images of the specimen with a microscope and analyze the pathological changes.</li>
	</ol>
	</li>
</ol>

Establishing a Mouse Model for Candida albicans-Associated Catheter-Related Infection

<ol>
	<li>Kojic, E. M., Darouiche, R. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Candida+infections+of+medical+devices.">Candida infections of medical devices.</a> microbiology reviews. 17 (2), 255-267 (2004).</li><li>Giri, S., Kindo, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+Candida+species+causing+blood+stream+infection.">A review of Candida species causing blood stream infection.</a> Indian Journal of Medical Microbiology. 30 (3), 270-278 (2012).</li><li>Weinstein, R. A., Darouiche, R. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Device-associated+infections:+A+macroproblem+that+starts+with+microadherence.">Device-associated infections: A macroproblem that starts with microadherence.</a> Clinical Infectious Diseases. 33 (9), 1567-1572 (2001).</li><li>Mermel, L. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Guidelines+for+the+management+of+intravascular+catheter-related+infections.">Guidelines for the management of intravascular catheter-related infections.</a> Clinical Infectious Diseases. 32 (9), 1249-1272 (2001).</li><li>Seidler, M., Salvenmoser, S., M&#252;ller, F. -. M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+effects+of+micafungin+against+Candida+biofilms+on+polystyrene+and+central+venous+catheter+sections.">In vitro effects of micafungin against Candida biofilms on polystyrene and central venous catheter sections.</a> International Journal of Antimicrobial Agents. 28 (6), 568-573 (2006).</li><li>Chaves, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diagnosis+and+treatment+of+catheter-related+bloodstream+infection:+Clinical+guidelines+of+the+Spanish+Society+of+Infectious+Diseases+and+Clinical+Microbiology+and+(SEIMC)+and+the+Spanish+Society+of+Spanish+Society+of+Intensive+and+Critical+Care+Medicine+and+Coronary+Units+(SEMICYUC).">Diagnosis and treatment of catheter-related bloodstream infection: Clinical guidelines of the Spanish Society of Infectious Diseases and Clinical Microbiology and (SEIMC) and the Spanish Society of Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC).</a> Medicina Intensiva. 42 (1), 5-36 (2018).</li><li>Raad, I. I., Bodey, G. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Infectious+complications+of+indwelling+vascular+catheters.">Infectious complications of indwelling vascular catheters.</a> Clinical Infectious Diseases. 15 (2), 197-208 (1992).</li><li>Paul DiMondi, V., Townsend, M. L., Johnson, M., Durkin, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antifungal+catheter+lock+therapy+for+the+management+of+a+persistent+Candida+albicans+bloodstream+infection+in+an+adult+receiving+hemodialysis.">Antifungal catheter lock therapy for the management of a persistent Candida albicans bloodstream infection in an adult receiving hemodialysis.</a> Pharmacotherapy. 34 (7), e120-e127 (2014).</li><li>Bouza, E., Guinea, J., Guembe, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+antifungals+against+candida+biofilm+in+catheter-related+candidemia.">The role of antifungals against candida biofilm in catheter-related candidemia.</a> Antibiotics (Basel). 4 (1), 1-17 (2014).</li><li>Raad, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrastructural+analysis+of+indwelling+vascular+catheters:+a+quantitative+relationship+between+luminal+colonization+and+duration+of+placement.">Ultrastructural analysis of indwelling vascular catheters: a quantitative relationship between luminal colonization and duration of placement.</a> The Journal of Infectious Diseases. 168 (2), 400-407 (1993).</li><li>Yousif, A., Jamal, M. A., Raad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biofilm-based+central+line-associated+bloodstream+infections.">Biofilm-based central line-associated bloodstream infections.</a> Advances in Experimental Medicine and Biology. 830, 157-179 (2015).</li><li>Douglas, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Candida+biofilms+and+their+role+in+infection.">Candida biofilms and their role in infection.</a> Trends in Microbiology. 11 (1), 30-36 (2003).</li><li>Mack, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biofilm+formation+in+medical+device-related+infection.">Biofilm formation in medical device-related infection.</a> International Journal of Artificial Organs. 29 (4), 343-359 (2006).</li><li>Schinabeck, M. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rabbit+model+of+Candida+albicans+biofilm+infection:+liposomal+amphotericin+B+antifungal+lock+therapy.">Rabbit model of Candida albicans biofilm infection: liposomal amphotericin B antifungal lock therapy.</a> Antimicrobial Agents and Chemotherapy. 48 (5), 1727-1732 (2004).</li><li>Anaissie, E. J., Rex, J. H., Uzun, O., Vartivarian, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Predictors+of+adverse+outcome+in+cancer+patients+with+candidemia.">Predictors of adverse outcome in cancer patients with candidemia.</a> The American Journal of Medicine. 104 (3), 238-245 (1998).</li><li>Fujimoto, K., Takemoto, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficacy+of+liposomal+amphotericin+B+against+four+species+of+Candida+biofilms+in+an+experimental+mouse+model+of+intravascular+catheter+infection.">Efficacy of liposomal amphotericin B against four species of Candida biofilms in an experimental mouse model of intravascular catheter infection.</a> Journal of Infection and Chemotherapy. 24 (12), 958-964 (2018).</li><li>Shuford, J. A., Rouse, M. S., Piper, K. E., Steckelberg, J. M., Patel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+caspofungin+and+amphotericin+B+deoxycholate+against+Candida+albicans+biofilms+in+an+experimental+intravascular+catheter+infection+model.">Evaluation of caspofungin and amphotericin B deoxycholate against Candida albicans biofilms in an experimental intravascular catheter infection model.</a> The Journal of Infectious Diseases. 194 (5), 710-713 (2006).</li><li>Koh, A. Y., K&#246;hler, J. R., Coggshall, K. T., Van Rooijen, N., Pier, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mucosal+damage+and+neutropenia+are+required+for+Candida+albicans+dissemination.">Mucosal damage and neutropenia are required for Candida albicans dissemination.</a> PLoS Pathogens. 4 (2), e35 (2008).</li><li>Tucey, T. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glucose+homeostasis+is+important+for+immune+cell+viability+during+candida+challenge+and+host+survival+of+systemic+fungal+infection.">Glucose homeostasis is important for immune cell viability during candida challenge and host survival of systemic fungal infection.</a> Cell Metabolism. 27 (5), 988-1006 (2018).</li><li>Lawrence, E. L., Turner, I. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Materials+for+urinary+catheters:+a+review+of+their+history+and+development+in+the+UK.">Materials for urinary catheters: a review of their history and development in the UK.</a> Medical Engineering &amp; Physics. 27 (6), 443-453 (2005).</li><li>Schumm, K., Lam, T. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Types+of+urethral+catheters+for+management+of+short-term+voiding+problems+in+hospitalized+adults:+a+short+version+Cochrane+review.">Types of urethral catheters for management of short-term voiding problems in hospitalized adults: a short version Cochrane review.</a> Neurourology and Urodynamics. 27 (8), 738-746 (2008).</li><li>Mo, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+evaluation+of+a+film+forming+system+containing+myricetin+and+miconazole+nitrate+for+preventing+candida+albicans+catheter-related+infection.">Development and evaluation of a film forming system containing myricetin and miconazole nitrate for preventing candida albicans catheter-related infection.</a> Microbial Drug Resistance. 28 (4), 468-483 (2022).</li><li>Balikci, E., Yilmaz, B., Tahmasebifar, A., Baran, E. T., Kara, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+modification+strategies+for+hemodialysis+catheters+to+prevent+catheter-related+infections:+A+review.">Surface modification strategies for hemodialysis catheters to prevent catheter-related infections: A review.</a> Journal of Biomedical Materials Research. Part B, Applied Biomaterials. 109 (3), 314-327 (2021).</li><li>Mar&#237;a, L. T., Alejandro, G. S., Mar&#237;a Jes&#250;s, P. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Central+venous+catheter+insertion:+Review+of+recent+evidence.">Central venous catheter insertion: Review of recent evidence.</a> Best Practice &amp; Research. Clinical Anaesthesiology. 35 (1), 135-140 (2021).</li><li>Kojic, E. M., Darouiche, R. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Candida+infections+of+medical+devices.">Candida infections of medical devices.</a> Clinical Microbiology Reviews. 17 (2), 255-267 (2004).</li><li>He, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retrospective+analysis+of+microbial+colonization+patterns+in+central+venous+catheters,+2013-2017.">Retrospective analysis of microbial colonization patterns in central venous catheters, 2013-2017.</a> Journal of Healthcare Engineering. 2019, 8632701 (2019).</li><li>Mo, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+and+in+vivo+effects+of+the+combination+of+myricetin+and+miconazole+nitrate+incorporated+to+thermosensitive+hydrogels+on+C.">In vitro and in vivo effects of the combination of myricetin and miconazole nitrate incorporated to thermosensitive hydrogels on C.</a> albicans biofilms. Phytomedicine. 71, 153223 (2020).</li><li>Cant&#243;n-Bulnes, M. L., Garnacho-Montero, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Practical+approach+to+the+management+of+catheter-related+bloodstream+infection.">Practical approach to the management of catheter-related bloodstream infection.</a> Revista Espanola de Quimioterapia. 32 Suppl 2 (Suppl 2), 38-41 (2019).</li><li>B&#246;hlke, M., Uliano, G., Barcellos, F. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hemodialysis+catheter-related+infection:+prophylaxis,+diagnosis+and+treatment.">Hemodialysis catheter-related infection: prophylaxis, diagnosis and treatment.</a> The Journal of Vascular Access. 16 (5), 347-355 (2015).</li><li>Fang, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+different+tissue+specimen+pretreatment+methods+on+microbial+culture+results+in+the+diagnosis+of+periprosthetic+joint+infection.">Effects of different tissue specimen pretreatment methods on microbial culture results in the diagnosis of periprosthetic joint infection.</a> Bone &amp; Joint Research. 10 (2), 96-104 (2021).</li><li>Naumenko, Z. S., Silanteva, T. A., Ermakov, A. M., Godovykh, N. V., Klushin, N. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Challenging+diagnostics+of+biofilm+associated+periprosthetic+infection+in+immunocompromised+patient:+A+clinical+case.">Challenging diagnostics of biofilm associated periprosthetic infection in immunocompromised patient: A clinical case.</a> Open Access Macedonian Journal of Medical Sciences. 7 (5), 786-790 (2019).</li><li>Cai, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metagenomic+next+generation+sequencing+improves+diagnosis+of+prosthetic+joint+infection+by+detecting+the+presence+of+bacteria+in+periprosthetic+tissues.">Metagenomic next generation sequencing improves diagnosis of prosthetic joint infection by detecting the presence of bacteria in periprosthetic tissues.</a> International Journal of Infectious Diseases. 96, 573-578 (2020).</li><li>Samanipour, A., Dashti-Khavidaki, S., Abbasi, M. R., Abdollahi, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antibiotic+resistance+patterns+of+microorganisms+isolated+from+nephrology+and+kidney+transplant+wards+of+a+referral+academic+hospital.">Antibiotic resistance patterns of microorganisms isolated from nephrology and kidney transplant wards of a referral academic hospital.</a> Journal of Research in Pharmacy Practice. 5 (1), 43-51 (2016).</li><li>Huang, G., Huang, Q., Wei, Y., Wang, Y., Du, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiple+roles+and+diverse+regulation+of+the+Ras/cAMP/protein+kinase+A+pathway+in+Candida+albicans.">Multiple roles and diverse regulation of the Ras/cAMP/protein kinase A pathway in Candida albicans.</a> Molecular Microbiology. 111 (1), 6-16 (2019).</li><li>Garlito-D&#237;az, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+antifungal-loaded+sol-gel+can+prevent+candida+albicans+prosthetic+joint+infection.">A new antifungal-loaded sol-gel can prevent candida albicans prosthetic joint infection.</a> Antibiotics (Basel). 10 (6), 711 (2021).</li></ol>

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

CRI is one of the most common nosocomial infections in clinical practice23. Pathogens in the skin appendages, such as the epidermis, sebaceous glands, and hair follicles, are all possible causes of CRI23,24. Candida is the third largest pathogen that causes CRI, in which Candida albicans was the most common type of biofilm infection25,26. Therefore, we aimed to bu...

In recent years, with the development and application of biomedical materials, implant-related infections are emerging as difficult clinical problems1,2. With the wide application of medical catheters in clinics, the number of related infections and deaths is huge every year3,4. The common infection routes of a catheter-related infection (CRI) include: (1) pathogens on the surface of the skin infiltrate into the body and adhere to the outer surface of the catheter5,6,7; (2) improper aseptic operation-derived pathogens invade, adhere and colonize on the catheter; (3) pathogens in the blood circulation adhere and colonize on the catheter; (4) drugs contaminated by pathogenic microorganism.
Candida is the third most common reason for CRI8,9. It is very likely to cause bloodstream infection and other life-threatening invasive candidiasis after biofilms are formed on the surface of the implant. The prognosis is poor, and the mortality rate is high2. It is reported that biofilms are formed on the surface of the catheter within 2 weeks after central venous insertion and in the lumen of the catheter a few weeks later10,11.
Candida albicans (C. albicans) biofilms formed on medical catheters exhibit a double-layer network composed of yeast, stroma, and mycelium12,13. The formation of C. albicans biofilms is not only a key for drug resistance and immune evasion13 but also vital to produce disseminated spores, which leads to further hematogenous infection2,12 and results in more serious and even life-threatening consequences. C. albicans-associated CRI is a major cause of clinical fungal bloodstream infections7,14, and more than 40% of patients with C. albicans infection in the central venous catheter will develop into bacteremia15.
According to the Infectious Disease Society of America, the recommended treatment of Candida CRI includes (1) removal of the infected catheter; (2) subjecting the patients to a 14 days-systemic antifungal therapy8; (3) reimplanting a new catheter4. However, in clinical applications, catheters cannot be fully removed sometimes. Some patients can only be treated with systemic antibiotics and antimicrobial lock therapy, accompanied by strong side effects16,17.
Existing animal models of C. albicans, such as the oropharyngeal candidiasis model, vaginal candidiasis model, and invasive systemic infection model caused by candidiasis18,19 cannot correlate well with the clinical CRI. Therefore, in this study, a C. albicans-associated CRI model in mice was established. Clinical commonly used polyethylene catheters were used as subcutaneous implants20,21, and C. albicans were inoculated on the skin surface to simulate the adhesion of C. albicans to the medical catheters and the formation of biofilms.
This model has been successfully used in our laboratory to screen the anti-biofilm effect of different therapeutics22. In addition, due to the lag detection of C. albicans after catheter infection, a C. albicans strain containing enhanced green fluorescent protein (EGFP) was constructed and inoculated in mice to facilitate the intuitive observation of the colonies and biofilms of C. albicans on the implanted catheter.

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a catheter-related candida albicans infection model in mouse

Catheter-related infection (CRI) is a common nosocomial infection caused by candida albicans during catheter implantation. Typically, biofilms are formed on the outer surface of the catheter and lead to disseminated infections, which are fatal to patients. There are no effective prevention and treatment management in clinics. Therefore, it is urgent to establish an animal model of CRI for the preclinical screening of new strategies for its prevention and treatment. In this study, a polyethylene catheter, a widely used medical catheter, was inserted into the back of the BALB/c mice after hair removal. Candida albicans ATCC MYA-2876 (SC5314) expressing enhanced green fluorescent protein was subsequently inoculated on the skin's surface along the catheter. Intense fluorescence was observed on the surface of the catheter under a fluorescent microscope 3 days later. Mature and thick biofilms were found on the surface of the catheter via scanning electron microscopy. These results indicated the adhesion, colonization, and biofilm formation of candida albicans on the surface of the catheter. The hyperplasia of the epidermis and the infiltration of inflammatory cells in the skin specimens indicated the histopathological changes of the CRI-associated skin. To sum up, a mouse CRI model was successfully established. This model is expected to be helpful in the research and development of therapeutic management for candida albicans associated CRI.

The C. albicans and biofilms on the catheters could be observed by the SEM. As shown in Figure 322, the surface of the polyethylene catheters in the catheter group was smooth, and no adhered pathogenic microorganism was observed. However, mature and dense C. albicans biofilms were visible on the surface of the polyethylene catheters in the model group, indicating that C. albicans could successfully colonize and form biofilms on the catheter ...

Watch this Scientific Journal Video about Enhancing Candida albicans Detection in Catheter Infections Using Fluorescent Protein Tagging at JoVE.com

Author Spotlight: Enhancing Candida albicans Detection in Catheter Infections Using Fluorescent Protein Tagging 

We establish a mouse model of C.albicans-associated catheter-related infection (CRI), in which biofilm forms on the catheter, and the interaction between C.albicans and host correlates well with the clinical CRI. This model helps screen therapies for C.albicans biofilm-associated CRI, laying a foundation for clinical transformation.

A Catheter-Related Candida albicans Infection Model in Mouse

Catheter-related infection (CRI) is a common nosocomial infection caused by candida albicans during catheter implantation. Typically, biofilms are formed ...

a-catheter-related-candida-albicans-infection-model-in-mouse

Research

JoVE Journal

Immunology and Infection

1.3K Views.  Xi’an Jiaotong University. We establish a mouse model of C.albicans-associated catheter-related infection (CRI), in which biofilm forms on the catheter, and the interaction between C.albicans and host correlates well with the clinical CRI. This model helps screen therapies for C.albicans biofilm-associated CRI, laying a foundation for clinical transformation.

Video: Author Spotlight: Enhancing Candida albicans Detection in Catheter Infections Using Fluorescent Protein Tagging 

A 96 Well Microtiter Plate-based Method for Monitoring Formation and Antifungal Susceptibility Testing of Candida albicans Biofilms

Candida albicans remains the most frequent cause of fungal infections in an expanding population of compromised patients and candidiasis is now the third most common infection in US hospitals. Different manifestations of candidiasis are associated with biofilm formation, both on host tissues and/or medical devices (i.e. catheters). Biofilm formation carries negative clinical implications, as cells within the biofilms are protected from host immune responses and from the action of antifungals. We have developed a simple, fast and robust in vitro model for the formation of C. albicans biofilms using 96 well microtiter-plates, which can also be used for biofilm antifungal susceptibility testing. The readout of this assay is colorimetric, based on the reduction of XTT (a tetrazolium salt) by metabolically active fungal biofilm cells. A typical experiment takes approximately 24 h for biofilm formation, with an additional 24 h for antifungal susceptibility testing. Because of its simplicity and the use of commonly available laboratory materials and equipment, this technique democratizes biofilm research and represents an important step towards the standardization of antifungal susceptibility testing of fungal biofilms.

A 96 Well Microtiter Plate-based Method for Monitoring Formation and Antifungal Susceptibility Testing of Candida albicans Biofilms

We describe a simple, rapid and robust method for the formation of Candida albicans biofilms using 96 well microtiter plates and its utility in antifungal susceptibility testing of cells within biofilms.

Candida albicans remains the most frequent cause of fungal infections in an expanding population of compromised patients and candidiasis is now the third ...

Protocols for Vaginal Inoculation and Sample Collection in the Experimental Mouse Model of Candida vaginitis

Vulvovaginal candidiasis (VVC), caused by Candida species, is a fungal infection of the lower female genital tract that affects approximately 75% of otherwise healthy women during their reproductive years18,32-34. Predisposing factors include antibiotic usage, uncontrolled diabetes and disturbance in reproductive hormone levels due to pregnancy, oral contraceptives or hormone replacement therapies33,34. Recurrent VVC (RVVC), defined as three or more episodes per year, affects a separate 5 to 8% of women with no predisposing factors33.
An experimental mouse model of VVC has been established and used to study the pathogenesis and mucosal host response to Candida3,4,11,16,17,19,21,25,37. This model has also been employed to test potential antifungal therapies in vivo13,24. The model requires that the animals be maintained in a state of pseudoestrus for optimal Candida colonization/infection6,14,23. Under such conditions, inoculated animals will have detectable vaginal fungal burden for weeks to months. Past studies show an extremely high parallel between the animal model and human infection relative to immunological and physiological properties3,16,21. Differences, however, include a lack of Candida as normal vaginal flora and a neutral vaginal pH in the mice.
Here, we demonstrate a series of key methods in the mouse vaginitis model that include vaginal inoculation, rapid collection of vaginal specimens, assessment of vaginal fungal burden, and tissue preparations for cellular extraction/isolation. This is followed by representative results for constituents of vaginal lavage fluid, fungal burden, and draining lymph node leukocyte yields. With the use of anesthetics, lavage samples can be collected at multiple time points on the same mice for longitudinal evaluation of infection/colonization. Furthermore, this model requires no immunosuppressive agents to initiate infection, allowing immunological studies under defined host conditions. Finally, the model and each technique introduced here could potentially give rise to use of the methodologies to examine other infectious diseases of the lower female genital tract (bacterial, parasitic, viral) and respective local or systemic host defenses.

Protocols for Vaginal Inoculation and Sample Collection in the Experimental Mouse Model of Candida vaginitis

Key techniques to be used in the evaluation of Candida vaginitis in an experimental animal model are described. The methods will allow rapid collection of vaginal specimens and lymphocytes from draining lumbar lymph nodes. These techniques could give rise to mouse models of other diseases in the female lower genital tract.

Vulvovaginal candidiasis (VVC), caused by Candida species, is a fungal infection of the lower female genital tract that affects approximately 75% of ...

Studying Microbial Communities In Vivo: A Model of Host-mediated Interaction Between Candida Albicans and Pseudomonas Aeruginosa in the Airways

Studying host-pathogen interaction enables us to understand the underlying mechanisms of the pathogenicity during microbial infection. The prognosis of the host depends on the involvement of an adapted immune response against the pathogen1. Immune response is complex and results from interaction of the pathogens and several immune or non-immune cellular types2. In vitro studies cannot characterise these interactions and focus on cell-pathogen interactions. Moreover, in the airway3, particularly in patients with suppurative chronic lung disease or in mechanically ventilated patients, polymicrobial communities are present and complicate host-pathogen interaction. Pseudomonas aeruginosa and Candida albicans are both problem pathogens4, frequently isolated from tracheobronchial samples, and associated to severe infections, especially in intensive care unit5. Microbial interactions have been reported between these pathogens in vitro but the clinical impact of these interactions remains unclear6. To study the interactions between C. albicans and P. aeruginosa, a murine model of C. albicans airways colonization, followed by a P. aeruginosa-mediated acute lung infection was performed.

Studying Microbial Communities In Vivo: A Model of Host-mediated Interaction Between Candida Albicans and Pseudomonas Aeruginosa in the Airways

While in vitro study of host-pathogen interactions allow the characterization of specific immune responses, in vivo models are required to observe the effects of complex responses. Using Candida albicans exposure followed by Pseudomonas aeruginosa-mediated lung infection, we established a murine model of microbial interactions involved in ventilator-associated pneumonia pathogenicity.

Studying host-pathogen interaction enables us to understand the underlying mechanisms of the pathogenicity during microbial infection. The prognosis of ...

Influenza A Virus Studies in a Mouse Model of Infection

Influenza viruses cause over 500,000 deaths worldwide1 and are associated with an annual cost of 12 - 14 billion USD in the United States alone considering direct medical and hospitalization expenses and work absenteeism2. Animal models are crucial in Influenza A virus (IAV) studies to evaluate viral pathogenesis, host-pathogen interactions, immune responses, and the efficacy of current and/or novel vaccine approaches as well as antivirals. Mice are an advantageous small animal model because their immune system is evolutionarily similar to that found in humans, they are available from commercial vendors as genetically identical subjects, there are multiple strains that can be exploited to evaluate the genetic basis of infections, and they are relatively inexpensive and easy to manipulate. To recapitulate IAV infection in humans via the airways, mice are first anesthetized prior to intranasal inoculation with infectious IAVs under proper biosafety containment. After infection, the pathogenesis of IAVs is determined by monitoring daily the morbidity (body weight loss) and mortality (survival) rate. In addition, viral pathogenesis can also be evaluated by assessing virus replication in the upper (nasal mucosa) or lower (lungs) respiratory tract of infected mice. Humoral responses upon IAV infection can be rapidly evaluated by non-invasive bleeding and secondary antibody detection assays aimed at detecting the presence of total or neutralizing antibodies. Here, we describe the common methods used to infect mice intranasally (i.n) with IAV and evaluate pathogenesis, humoral immune responses and protection efficacy.

Influenza A viruses (IAVs) are important human respiratory pathogens. To understand the pathogenicity of IAVs and to perform preclinical testing of novel vaccine approaches, animal models mimicking human physiology are required. Here, we describe techniques to evaluate IAV pathogenesis, humoral responses and vaccine efficacy using a mouse model of infection.

Influenza viruses cause over 500,000 deaths worldwide1 and are associated with an annual cost of 12 - 14 billion USD in the United States alone ...

Visualization of Biofilm Formation in Candida albicans Using an Automated Microfluidic Device

Candida albicans is the most common fungal pathogen of humans, causing about 15% of hospital-acquired sepsis cases. A major virulence attribute of C. albicans is its ability to form biofilms, structured communities of cells attached to biotic and abiotic surfaces. C. albicans biofilms can form on host tissues, such as mucosal layers, and on medical devices, such as catheters, pacemakers, dentures, and joint prostheses. Biofilms pose significant clinical challenges because they are highly resistant to physical and chemical perturbations, and can act as reservoirs to seed disseminated infections. Various in vitro assays have been utilized to study C. albicans biofilm formation, such as microtiter plate assays, dry weight measurements, cell viability assays, and confocal scanning laser microscopy. All of these assays are single end-point assays, where biofilm formation is assessed at a specific time point. Here, we describe a protocol to study biofilm formation in real-time using an automated microfluidic device under laminar flow conditions. This method allows for the observation of biofilm formation as the biofilm develops over time, using customizable conditions that mimic those of the host, such as those encountered in vascular catheters. This protocol can be used to assess the biofilm defects of genetic mutants as well as the inhibitory effects of antimicrobial agents on biofilm development in real-time.

Visualization of Biofilm Formation in Candida albicans Using an Automated Microfluidic Device

This protocol describes the use of a customizable automated microfluidic device to visualize biofilm formation in Candida albicans under host physiological conditions.

Candida albicans is the most common fungal pathogen of humans, causing about 15% of hospital-acquired sepsis cases. A major virulence attribute of C. ...

Deep Dermal Injection As a Model of Candida albicans Skin Infection for Histological Analyses

The skin is an extremely extended organ of the body and, due to this large surface, it is continuously exposed to microorganisms. Skin damage can easily lead to infections in the dermis which can, in turn, result in the dissemination of pathogens into the bloodstream. Understanding how the immune system fights infections at the very early stage and how the host can eliminate the pathogens is an important step to set the base for future therapeutic interventions. Here we describe a model of Candida albicans infection that can visualize the processes that occur early during an infection, including when the pathogen has passed the epithelial barrier, as well as the immune response elicited by the C. albicans invasion. We used this infection model to perform histological analyses that show the immune cells that infiltrate the skin as well as the presence and localization of the pathogen. Samples collected after the infection can be processed for RNA extraction.

Deep Dermal Injection As a Model of Candida albicans Skin Infection for Histological Analyses

Here we describe a protocol that allows histological and molecular analysis of skin samples after Candida albicans intradermal injection. This protocol maintains the structural integrity of the skin and allows for the localization of tissue-resident or newly recruited immune cells as well as the pathogen distribution.

The skin is an extremely extended organ of the body and, due to this large surface, it is continuously exposed to microorganisms. Skin damage can easily ...

Intracranial Subarachnoidal Route of Infection for Investigating Roles of Streptococcus suis Biofilms in Meningitis in a Mouse Infection Model

Streptococcus suis is not only a major bacterial pathogen of pigs worldwide but also an emerging zoonotic agent. In humans and pigs, meningitis is a major manifestation of S. suis infections. A suitable infection model is an essential tool to understand the mechanisms of diseases caused by pathogens. Several routes of infection in mice have been developed to study the pathogenesis of S. suis infection. However, the intraperitoneal, intranasal, and intravenous routes of infection are not suitable for studying the roles of S. suis surface components in meningitis directly in the brain, such as the extracellular matrix from biofilms. Although intracisternal inoculation has been used for S. suis infection, the precise injection site has not been described. Here, the intracranial subarachnoidal route of infection was described in a mouse model to investigate the roles of biofilms in S. suis meningitis. S. suis planktonic cells or biofilm state cells were directly injected into the subarachnoid space of mice through the injection site located 3.5 mm rostral from the bregma. Histopathological analysis and increased mRNA expression of TLR2 and cytokines of the brain tissue from mice injected with biofilm state cells clearly indicated that S. suis biofilm plays definitive roles in S. suis meningitis. This route of infection has obvious advantages over other routes of infection, allowing the study of the host-bacterium interaction. Furthermore, it permits the effect of bacterial components on host immune responses directly in the brain to be assessed, and mimics bacterial entrance into the central nervous system. This route of infection can be extended for investigating the mechanisms of meningitis caused by other bacteria. In addition, it can also be used to test the efficacy of drugs against bacterial meningitis.

Intracranial Subarachnoidal Route of Infection for Investigating Roles of Streptococcus suis Biofilms in Meningitis in a Mouse Infection Model

Here, we describe the intracranial subarachnoidal route of infection in mice to study roles of biofilms in Streptococcus suis meningitis. This infection model is also suitable for studying the pathogenesis of other bacterial meningitis and the efficacy of new drugs against bacterial meningitis.

Streptococcus suis is not only a major bacterial pathogen of pigs worldwide but also an emerging zoonotic agent. In humans and pigs, meningitis is a major ...

Daily Phototherapy with Red Light to Regulate Candida albicans Biofilm Growth

Here, we present a protocol to assess the outcomes of per diem red light treatment on the growth of Candida albicans biofilm. To increase the planktonic growth of C. albicans SN425, the inoculums grew on Yeast Nitrogen Base media. For biofilm formation, RPMI 1640 media, which have high concentrations of amino acids, were applied to help biofilm growth. Biofilms of 48 h were treated twice a day for a period of 1 min with a non-coherent light device (red light; wavelength = 635 nm; energy density = 87.6 J&#183;cm-2). As a positive control (PC), 0.12% chlorhexidine (CHX) was applied, and as a negative control (NC), 0.89% NaCl was applied to the biofilms. Colony forming units (CFU), dry-weight, soluble and insoluble exopolysaccharides were quantified after treatments. Briefly, the protocol presented here is simple, reproducible and provides answers regarding viability, dry-weight and extracellular polysaccharide amounts after red light treatment.

Daily Phototherapy with Red Light to Regulate Candida albicans Biofilm Growth

Here, we present a protocol to assess the outcome of red light application on the growth of Candida albicans biofilm. A non-coherent red light device with the wavelength of 635 nm and energy density of 87.6 J&#183;cm-2 was applied throughout the growth of Candida albicans biofilms for 48 h.

Here, we present a protocol to assess the outcomes of per diem red light treatment on the growth of Candida albicans biofilm. To increase the planktonic ...

Visualization of Candida albicans in the Murine Gastrointestinal Tract Using Fluorescent In Situ Hybridization

Candida albicans is a fungal component of the gut microbiota in humans and many other mammals. Although C. albicans does not cause symptoms in most colonized hosts, the commensal reservoir does serve as a repository for infectious disease, and the presence of high fungal titers in the gut is associated with inflammatory bowel disease. Here, we describe a method to visualize C. albicans cell morphology and localization in a mouse model of stable gastrointestinal colonization. Colonization is established using a single dose of C. albicans in animals that have been treated with oral antibiotics. Segments of gut tissue are fixed in a manner that preserves the architecture of luminal contents (microorganisms and mucus) as well as the host mucosa. Finally, fluorescent in situ hybridization is performed using probes against fungal rRNA to stain for C. albicans and hyphae. A key advantage of this protocol is that it allows for simultaneous observation of C. albicans cell morphology and its spatial association with host structures during gastrointestinal colonization.

Visualization of Candida albicans in the Murine Gastrointestinal Tract Using Fluorescent In Situ Hybridization

The purpose of this protocol is to visualize Candida albicans cell shape and localization in the mammalian gastrointestinal tract.

Candida albicans is a fungal component of the gut microbiota in humans and many other mammals. Although C. albicans does not cause symptoms in most ...

Clarifying and Imaging Candida albicans Biofilms

The microbial fungus Candida albicans can undergo a change from commensal colonization to virulence that is strongly correlated with its ability to switch from yeast-form growth to hyphal growth. Cells initiating this process become adherent to surfaces as well as to each other, with the resulting development of a biofilm colony. This commonly occurs not only on mucosal tissue surfaces in yeast infections, but also on medical implants such as catheters. It is well known that biofilm cells are resistant to antifungal drugs, and that cells that shed from the biofilm can lead to dangerous systemic infections. Biofilms range from heavily translucent to opaque due to refractive heterogeneity. Therefore, fungal biofilms are difficult to study by optical microscopy. To visualize internal structural, cellular, and subcellular features, we clarify fixed intact biofilms by stepwise solvent exchange to a point of optimal refractive index matching. For C. albicans biofilms, sufficient clarification is attained with methyl salicylate (n = 1.537) to enable confocal microscopy from apex to base in 600 &#181;m biofilms with little attenuation. In this visualization protocol we outline phase contrast refractometry, the growth of laboratory biofilms, fixation, staining, solvent exchange, the setup for confocal fluorescence microscopy, and representative results.

Clarifying and Imaging Candida albicans Biofilms

To view and quantify the internal features of Candida albicans biofilms, we prepare fixed intact specimens that are clarified by refractive index matching. Then, optical sectioning microscopy can be used to obtain three-dimensional image data though the full thickness of the biofilm.

The microbial fungus Candida albicans can undergo a change from commensal colonization to virulence that is strongly correlated with its ability to switch ...