Objective To evaluate the clinical features, risk factors and treatment outcomes of endogenous candida albicans endophthalmitis. Methods The clinical data of 11 patients (18 eyes) with vitreous specimen culture-proven endogenous candida endophthalmitis were retrospective reviewed, including risk factors, clinical features and therapeutic methods and outcomes. Results There were 4 males and 7 females patients, aged from 19 to 72 years with a mean age of （41.61plusmn;9.76）years. Seven patients had bilateral endophthalmitis. They had histories of induced abortion (2 patients), intravenous transfusion (3 patients), colon cancer surgery (1 patient), chemotherapy after surgery of malignant lymphoma of colon (1 patient), renal transplantation (1 patient), acute necrotic pancreatitis surgery (1 patient) and diabetes (1 patient). One patient has no special medical history. All patients had no history of ocular trauma or intraocular surgery. The major complaints included blurred vision, metamorphopsia and floaters. It taken an average of (15.23plusmn;8.70) days (3-38 days) for patients to go to the hospital after getting those symptoms. The main clinical manifestations included pre- or sub-retinal white exudates and vitreous inflammations.In 18 eyes, 11 received vitreous surgery, and the other 7 were treated by intravitreal administration of anti-fungal drugs. Ten patients also underwent systemic anti-fungal therapy. The candida endophthalmitis was cured for 10/11 patients and most of them with increased visual acuity. Conclusions Endogenous candida albicans endophthalmitis is characterized by pre- or sub-retinal white exudates and vitreous inflammations. Non-standard intravenous transfusion, induced abortion and malignancy are its major risk factors. Pars plana vitrectomy or intravitreal delivery of anti-fungal drugs can cure this disease.
ObjectiveTo explore the function of intercellular adhesion A (icaA), fibrinogen binding protein (fbe), and accumulation-associated protein (aap) genes in formation of Staphylococcus epidermidis-Candida albicans mixed species biofilms. MethodsThe experiment was divided into 3 groups:single culture of Staphylococcus epidermidis ATCC35984 (S. epidermidis group) or Candida albicans ATCC10231 (C. albicans group), and co-culture of two strains (mixed group) to build in vitro biofilm model. Biofilm mass was detected by crystal violet semi-quantitative adherence assay at 2, 4, 6, 8, 12, 24, 48, and 72 hours after incubation. XTT assay was performed to determine the growth kinetics in the same time. Scanning electron microscopy (SEM) was used to observe the ultrastructure of the biofilms after 24 and 72 hours of incubation. The expressions of icaA, fbe, and aap genes were analyzed by real-time fluorescent quantitative PCR. ResultsCrystal violet semi-quantitative adherence assay showed that the biofilms thickened at 12 hours in the S. epidermidis and mixed groups; after co-cultured for 72 hours the thickness of biofilm in mixed group was more than that in the S. epidermidis group, and there was significant difference between 2 groups at the other time (P<0.05) except at 72 hours (P>0.05). In C. albicans group, the biofilm started to grow at 12 hours of cultivation, but the thickness of the biofilm was significantly lower than that in the mixed group in all the time points (P<0.05). XTT assay showed that the overall growth speed in the mixed group was greater than that in the C. albicans group, and it was greater than that in the S. epidermidis group at 48 hours; there was no significant difference in the growth speed between the mixed groups and the S. epidermidis group in the other time points (P>0.05) except at 12 hours (P<0.05). The absorbance (A) value in the mixed group was lower than that in the S. epidermidis group at 2 and 4 hours, but no significant difference was shown (P>0.05); the A value of mixed group was significantly higher than that of the C. albicans group after 6 hours (P<0.05). SEM observation showed that mature biofilms with complex structure formed in all groups. The real-time fluorescent quantitative PCR showed the expressions of fbe, icaA, and aap genes in mixed group increased 1.93, 1.52, and 1.46 times respectively at 72 hours compared with the S. epidermidis group (P<0.05). ConclusionMixed species biofilms have more complex structure and are thicker than single species biofilms of Staphylococcus epidermidis or Candida albicans, which is related to increased expressions of the icaA, fbe, and aap genes of Staphylococcus epidermidis.
ObjectiveTo establish an in vitro model of Candida albicans-Staphylococcus epidermidis mixed species biofilm on polyvinyl chloride (PVC) material, and to observe mixed species biofilm formation and its microstructure. MethodsStaphylococcus epidermidis bacteria (ATCC35984) and Candida albicans fungal (ATCC10231)were co-incubated with 0.5 cm diameter PVC pieces in tryptic soy broth (TSB) to form mixed specie biofilms (experimental group). At 2, 6, 12, 24, 48, and 72 hours, the thicknesses of the biofilms, the number of bacteria per sight, and the percentage of viable cells in biofilms were measured, and three-dimensional images of biofilms were obtained using confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) at 48 hours. PVC material cultured in the TSB medium served as control group. ResultsIn control group, there was no pathogenic bacteria adhesion on the PVC material surface. In experimental group, CLSM showed that colonies and biofilm formation were found at 6 hours after co-culture, and gradually increased with time. The pathogenic bacteria colonies reached the peak at 24 hours, and biofilm thickness attained peak value at 48 hours. In experimental group, the number of colony was significantly different among 2, 6, and 24 hours, and between 2, 6 hours and 48, 72 hours (P<0.05), but no significant difference was found among 24, 48, and 72 hours (P>0.05). The biofilm thickness showed significant difference between the other time points (P<0.05) except between 48 and 72 hours (P>0.05). The percentage of viable cells in the outer layers of the biofilm was significantly higher than that in inner and middle layers at 48 hours (P<0.05). Three-dimensional reconstruction displayed that the surface of mixd species was uneven; living bacterium mainly located at the protuberance, and dead bacteria mainly located at the concaves. SEM image showed that Staphylococcus epidermidis attached to various forms of Candida albicans (spores, pseudohyphae, hyphae) gradually, and formed multilayer reticulate sophisticated structure on the surface of PVC with time. ConclusionCandida albicans-Staphylococcus epidermidis mixed species biofilm is sophisticated in structure. The combination of CLSM, SEM, and three-dimensional image reconstruction technology is ideal for investigation of mixed species biofilm on PVC material.
Objective To investigate the infection rates of toxin-producing Clostridium difficile and Candida albicans in patients with antibiotic-associated diarrhea (AAD) in West China Hospital of Sichuan University, analyze their clinical characteristics and make a survey of the therapy. Methods Fecal specimens of AAD patients were collected in West China Hospital of Sichuan University from September 2014 to January 2015. Toxin-producing Clostridium difficile and Candida albicans were identified by polymerase chain reaction and then clinical data of cases was collected and analyzed. Results Twenty-eight patients with Clostridium difficile infection were detected from the 126 AAD patients, 20 patients (15.9%) in whom were infected with toxin-producing Clostridium difficile. Type A+B+, type A-B+, and type A+B- accounted for 35.7% (10/28), 35.7% (10/28) and 28.6% (8/28), respectively. Fifty-four patients (42.9%) with yeast infection were detected. The predominant isolate was Candida albicans, accounting for 20.6% (26/126), and the others were Candida glabrata (n=11), Candida tropical (n=10), Candida parapsilosis (n=3), Saccharomyces cerevisiae (n=2), Pichia pastoris (n=1), and Kodamaea ohmeri (n=1). Toxin-producing Clostridium difficile strains and Candida albicans strains were both isolated from 3 patients (2.4%). The main antibiotics used in AAD ppatients were penicillins, carbapenems, third generation cephalosporins, and fluoroquinolones. AAD patients were all with underlying diseases at different degrees. The main treatments were probiotics and montmorillonite powder. Conclusion The relatively high infection rates and complicated factors of AAD indicate that much more attention needs to be paid to the diagnosis and therapy of AAD by the clinical doctors.
ObjectiveTo study the effect of intercellular adhesion (ica) operon of Staphylococcus epidermidis on the inflammation associated with mixed biofilm of Staphylococcus epidermidis and Candida albicans on endotracheal tube material in rabbits. MethodsThe standard strains of Staphylococcus epidermidis RP62A (ica operon positive, positive group) and ATCC12228 (ica operon negative, negative group) were taken to prepare a bacterial solution with a concentration of 1×106 CFU/mL, respectively. Then, the two bacterial solutions were mixed with the standard strain of Candida albicans ATCC10231 of the same concentration to prepare a mixed culture solution at a ratio of 1∶1, respectively. The mixed culture solution was incubated with endotracheal tube material for 24 hours. The formation of mixed biofilm on the surface of the material was observed by scanning electron microscope. Thirty New Zealand rabbits, aged 4-6 months, were divided into two groups (n=15), and the endotracheal tube materials of the positive group and the negative group that were incubated for 24 hours were implanted beside the trachea. The body mass of rabbits in the two groups was measured before operation and at 1, 3, and 7 days after operation. At 1, 3, and 7 days after operation, the levels of interleukin 1β (IL-1β), IL-6, tumor necrosis factor α (TNF-α), and monocytechemotactic protein 1 (MCP-1) were detected by using an ELISA test kit. At 7 days after operation, the formation of mixed biofilm on the surface of the endotracheal tube materials was observed by scanning electron microscope, the inflammation and infiltration of tissues around the materials were observed by HE staining, and the bacterial infections in heart, lung, liver, and kidney were observed by plate colony counting method.ResultsScanning electron microscope observation showed that the mixed biofilm structure was obvious in the positive group after 24 hours in vitro incubation, but no mixed biofilm formation was observed in the negative group. In vivo studies showed that there was no significant difference in body mass between the two groups before operation and at 1, 3, and 7 days after operation (P>0.05). Compared with the negative group, the levels of MCP-1 and IL-1β at 1 day, and the levels of IL-1β, MCP-1, IL-6, and TNF-α at 3 and 7 days in the positive group all increased, with significant differences (P<0.05). Scanning electron microscope observation showed that a large amount of Staphylococcus epidermis and mixed biofilm structure were observed in the positive group, and a very small amount of bacteria was observed in the negative group with no mixed biofilm structure. HE staining of surrounding tissue showed inflammatory cell infiltration in both groups, and neutrophils and lymphocytes were more in the positive group than in the negative group. There was no significant difference in the number of bacterial infections in heart and liver between the two groups (P>0.05). The number of bacterial infections in lung and kidney in the positive group was higher than that in negative group (P<0.05).ConclusionIn the mixed infection of Staphylococcus epidermidis and Candida albicans, the ica operon may strengthen the structure of the biofilm and the spread of the biofilm in vivo, leading to increased inflammatory factors, and the bacteria are difficult to remove and persist.