The influence of substrate surface conditioning and biofilm age on the composition of Enterococcus faecalis biofilms.

AIM: To investigate the null hypothesis that neither the surface conditioning (collagen, serum, saliva) of hydroxyapatite (HA) discs, nor the biofilm age (3 days vs. 21 days) has a significant effect on the cellular and matrix composition of biofilms, using Enterococcus faecalis as the model organism. METHODOLOGY: Sterile HA discs were conditioned with collagen, saliva or serum, and inoculated with E. faecalis to form 3-day and 21-day-old biofilms. Unconditioned discs served as controls. The biofilms were analysed using culture-dependent and independent (confocal microscopy and biochemical analysis) methods, to determine the colony-forming units and the biofilm matrix composition (polysaccharides and proteins), respectively. Statistical analyses were performed using appropriate parametric and nonparametric tests (P = 0.05). RESULTS: Collagen conditioning significantly increased the number of CFUs in the 21-day biofilms, compared to the 3-day biofilms (P < 0.05). Although the biochemical analysis revealed that surface conditioning had no significant effect on the total carbohydrate content in the 21-day biofilms, confocal microscopic analysis revealed that collagen and saliva conditioning selectively increased the polysaccharide content of 21-day biofilms, compared to the 3-day biofilms (P < 0.05). CONCLUSIONS: The results of this study raise an important methodological concern that the substrate conditioning substances and biofilm age differentially influence the cellular and extracellular matrix components of E. faecalis biofilms.

The strength and spread of the electric field induced by transcranial rotating permanent magnet stimulation in comparison with conventional transcranial magnetic stimulation.

BACKGROUND: Weak or low intensity transcranial stimulation of the brain, such as low field magnetic stimulation and electrical stimulation, can produce significant functional and therapeutic neuromodulatory effects. NEW METHOD: We have recently developed a portable wearable multifocal brain stimulator called transcranial rotating permanent magnet stimulator (TRPMS) that uses rapidly spinning high field strength permanent magnets attached to a cap. It produces oscillatory stimuli of different frequencies and patterns. Here we compared the strengths and spatial profiles of the changing magnetic fields of a figure-of-eight transcranial magnetic stimulator (TMS) coil, a TRPMS prototype, and a scaled-up version of TRPMS. We measured field strengths and directions of voltages induced in a magnetic field sensor oriented along all three orthogonal axes. RESULTS AND COMPARISON WITH EXISTING METHODS: The spatial spread of the TRPMS-induced electric field is more restricted, and its shape and strength vary less with the orientation of the inductance than TMS. The maximum voltage induced by the current prototype is ∼7% of the maximal TMS output at depths corresponding to the human cerebral cortex from the scalp surface. This field strength can be scaled up by a factor ∼8 with a larger diametrically magnetized magnet. These comparative data allow us to estimate that intracortical effects of TRPMS could be stronger than other low intensity stimulation methods. CONCLUSIONS: TRPMS might enable greater uniformity, consistency and focality in stimulation of targeted cortical areas subject to significant anatomical variability. Multiple TRPMS microstimulators can also be combined to produce patterned multifocal spatiotemporal stimulation.

Assessing uptake of national HIV screening and testing guidance-Part 1: Awareness, use and usefulness.

BACKGROUND: In 2013, the Public Health Agency of Canada released the HIV Screening and Testing Guide (the Guide) to support routine HIV screening and testing practices of health care providers in Canada and promote early detection of new HIV cases. Little was known regarding health care providers' awareness and use of the Guide. OBJECTIVE: To determine Canadian health care providers' awareness, use and perceived usefulness of the Guide. METHODS: An open, anonymous online survey, including questions on awareness, use and usefulness, was developed with stakeholders, validated and pre-tested. It was then disseminated to a convenience sample of health care providers across Canada between June and August 2016. RESULTS: A total of 1,075 participants representing all Canadian provinces and territories responded to the survey, with the majority being nurses (54%) and physicians (12%). About two-thirds of respondents (65%) were aware of the Guide; of those, approximately half used it. Thirty-five percent of participants were not aware of the Guide, including none of the 173 health care providers in primary care (family/general practice). Among participants who were aware of and used the Guide, over 80% reported incorporating recommendations from the Guide into their practice and 77% reported frequently or always being able to find information they were looking for. CONCLUSIONS: The HIV Screening and Testing Guide appears to be very useful for those who are aware of it and use it; however, awareness of the Guide appears to be low in primary care. Although these results need to be interpreted in light of the convenience sample, it suggests broader dissemination efforts may be needed to reach all of the potential users of the Guide.

Assessing uptake of national HIV screening and testing guidance-Part 2: Knowledge, comfort and practice.

BACKGROUND: The Public Health Agency of Canada's (PHAC) HIV Screening and Testing Guide (the Guide) provides guidance to health care providers regarding who, when and how often to screen for HIV. HIV screening and testing is important in meeting the Joint United Nations Programme on HIV/AIDS' (UNAIDS) 90-90-90 targets towards HIV elimination. OBJECTIVE: To determine health care providers' levels of knowledge about and comfort with aspects of HIV testing, and to determine whether their HIV testing practices are consistent with the recommendations in the Guide. METHODS: An open, anonymous online survey that included questions on knowledge, comfort and HIV testing practices was developed with stakeholders, validated and pre-tested. It was then disseminated to a convenience sample of health care providers across Canada between June and August 2016. RESULTS: A total of 1,075 participants representing all Canadian provinces and territories responded to the survey, with the majority being nurses (54%) and physicians (12%). Overall, knowledge related to HIV testing was substantial, but 37% of respondents underestimated the percentage of people living with HIV in Canada who are unaware of their HIV status and only 32% of respondents knew that HIV patients are frequently symptomatic during the acute infection. Most participants were comfortable with HIV testing and approximately 50% reported offering HIV testing regularly. CONCLUSIONS: Although overall knowledge and practice were consistent with PHAC's HIV Screening and Testing Guide, some health care providers may underestimate the magnitude of undiagnosed HIV cases in Canada and may misinterpret the symptoms of acute HIV infection. While the amplitude of these results need to be interpreted in light of the convenience sample, addressing these knowledge gaps may facilitate earlier diagnosis of HIV among those who are unaware of their HIV status.

Evidence for optimal HIV testing intervals in HIV-negative individuals from various risk groups: a systematic review protocol.

BACKGROUND: Evidence-based recommendations for HIV testing are essential for health care providers. However, it is unclear whether there is sufficient evidence to support recommendations for HIV testing frequencies in a variety of HIV risk groups. OBJECTIVE: The aim of this document is to outline the methodological protocol of a systematic review that would gather evidence for the optimal frequency of HIV testing among individuals in various HIV risk groups with respect to personal and public health outcomes and cost-effectiveness. METHODS: This protocol adheres to the PRISMA-P reporting items, and the review is registered with PROSPERO. The target population includes individuals who may have undiagnosed HIV infection. Different frequencies of HIV testing will be compared and outcomes to do with personal and public health, patient values/preferences and costs will be examined. The search strategy will encompass searches in MEDLINE/Pubmed, Scopus, Embase, Cochrane, PsychINFO, and EconLit, as well as grey literature sources. Articles will be screened by title/abstract, and subsequently by full-text, in duplicate. Extraction of pertinent data from the screened references will be carried out by one reviewer and verified by a second. Multiple critical appraisal tools will be used to assess individual study quality, and the GRADE approach will be used to appraise the overall quality of the evidence. Data will be synthesized narratively, and the results will be published in a peer-reviewed journal. DISCUSSION: This systematic review, designed with extensive input from content experts, will help to identify key evidence to inform recommendations for HIV testing frequency.

Sitagliptin plus pantoprazole can restore but not maintain insulin independence after clinical islet transplantation: results of a pilot study.

AIMS: Resuming insulin use due to waning function is common after islet transplantation. Animal studies suggest that gastrointestinal hormones, including gastrin and incretins may increase ß-cell mass. We tested the hypothesis that pantoprazole plus sitagliptin, would restore insulin independence in islet transplant recipients with early graft insufficiency and determined whether this would persist after a 3-month washout. METHODS: Single-centre, uncontrolled, open label study of sitagliptin 100 mg daily plus pantoprazole 40 mg twice daily for 6 months. RESULTS: After 6 months of treatment, two of eight participants (25%) achieved the primary endpoint, defined as HbA1C < 42 mmol/mol (6%), fasting plasma glucose < 7.0 mmol, C-peptide > 0.5 nmol and no insulin use. There was a significant reduction in mean insulin dose, but no change in HbA1C or weight. There were no changes in the acute insulin response to arginine, the mixed meal tolerance test or blinded continuous glucose monitoring. After the washout, no participants met the primary endpoint and HbA1C increased from 45 ± 8 mmol/mol (6.3 ± 0.7%) to 51 ± 6 mmol/mol (6.8 ± 0.6%) (P < 0.05). Two participants had mild-moderate transient gastrointestinal side effects. There were no episodes of hypoglycaemia. CONCLUSIONS: Sitagliptin plus pantoprazole is well tolerated and safe and may restore insulin independence in some islet transplant recipients with early graft insufficiency, but this was not sustained when treatment was withdrawn. A larger, controlled trial is required to confirm the effectiveness of this combination to achieve insulin independence and to confidently exclude any persistent benefit for graft function. (Clinical Trials Registry No.: NCT00768651).

Forebrain-Specific Transgene Rescue of 11ß-HSD1 Associates with Impaired Spatial Memory and Reduced Hippocampal Brain-Derived Neurotrophic Factor mRNA Levels in Aged 11ß-HSD1 Deficient Mice.

Mice lacking the intracellular glucocorticoid-regenerating enzyme 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) are protected from age-related spatial memory deficits. 11ß-HSD1 is expressed predominantly in the brain, liver and adipose tissue. Reduced glucocorticoid levels in the brain in the absence of 11ß-HSD1 may underlie the improved memory in aged 11ß-HSD1 deficient mice. However, the improved glucose tolerance, insulin sensitisation and cardioprotective lipid profile associated with reduced peripheral glucocorticoid regeneration may potentially contribute to the cognitive phenotype of aged 11ß-HSD1 deficient mice. In the present study, transgenic mice with forebrain-specific overexpression of 11ß-HSD1 (Tg) were intercrossed with global 11ß-HSD1 knockout mice (HSD1KO) to examine the influence of forebrain and peripheral 11ß-HSD1 activity on spatial memory in aged mice. Transgene-mediated delivery of 11ß-HSD1 to the hippocampus and cortex of aged HSD1KO mice reversed the improved spatial memory retention in the Y-maze but not spatial learning in the watermaze. Brain-derived neurotrophic factor (BDNF) mRNA levels in the hippocampus of aged HSD1KO mice were increased compared to aged wild-type mice. Rescue of forebrain 11ß-HSD1 reduced BDNF mRNA in aged HSD1KO mice to levels comparable to aged wild-type mice. These findings indicate that 11ß-HSD1 regenerated glucocorticoids in the forebrain and decreased levels of BDNF mRNA in the hippocampus play a role in spatial memory deficits in aged wild-type mice, although 11ß-HSD1 activity in peripheral tissues may also contribute to spatial learning impairments in aged mice.

Decreased Npas4 and Arc mRNA Levels in the Hippocampus of Aged Memory-Impaired Wild-Type But Not Memory Preserved 11ß-HSD1 Deficient Mice.

Mice deficient in the glucocorticoid-regenerating enzyme 11ß-HSD1 resist age-related spatial memory impairment. To investigate the mechanisms and pathways involved, we used microarrays to identify differentially expressed hippocampal genes that associate with cognitive ageing and 11ß-HSD1. Aged wild-type mice were separated into memory-impaired and unimpaired relative to young controls according to their performance in the Y-maze. All individual aged 11ß-HSD1-deficient mice showed intact spatial memory. The majority of differentially expressed hippocampal genes were increased with ageing (e.g. immune/inflammatory response genes) with no genotype differences. However, the neuronal-specific transcription factor, Npas4, and immediate early gene, Arc, were reduced (relative to young) in the hippocampus of memory-impaired but not unimpaired aged wild-type or aged 11ß-HSD1-deficient mice. A quantitative reverse transcriptase-polymerase chain reaction and in situ hybridisation confirmed reduced Npas4 and Arc mRNA expression in memory-impaired aged wild-type mice. These findings suggest that 11ß-HSD1 may contribute to the decline in Npas4 and Arc mRNA levels associated with memory impairment during ageing, and that decreased activity of synaptic plasticity pathways involving Npas4 and Arc may, in part, underlie the memory deficits seen in cognitively-impaired aged wild-type mice.

Only high levels of dabigatran attenuate catheter thrombosis in vitro and in rabbits.

In patients with mechanical heart valves, thromboembolic events were more frequent with dabigatran, an oral thrombin inhibitor, than with warfarin. This observation raises the possibility that dabigatran may be less effective than conventional anticoagulants in patients with other blood-contacting devices, such as catheters. To address this, we compared the capacity of dabigatran and/or heparin to inhibit catheter-induced thrombin generation in vitro and to attenuate catheter occlusion in rabbits. Using a catheter-induced thrombin generation assay, concentrations of dabigatran over 100 ng/ml prolonged the lag time and time to peak thrombin, and reduced the peak thrombin concentration and endogenous thrombin potential in a concentration-dependent fashion. Compared with saline in a rabbit model of catheter thrombosis, dabigatran prolonged the mean time to catheter occlusion by 2.9- and 1.9-fold when plasma levels were 173 and 140 ng/ml, respectively; values comparable to median peak levels in humans given dabigatran 150 mg twice daily. In contrast, low-dose dabigatran, which produced a level of 60 ng/ml; a value comparable to the trough level of dabigatran in humans, did not prolong the time to occlusion. Whereas a 70 U/kg bolus of heparin prolonged the mean time to occlusion by 3.4-fold, a 15 U/kg bolus had no effect. When low-dose dabigatran was given in combination with 15 U/kg heparin, the mean time to occlusion was prolonged by 2.7-fold. These findings suggest that only peak levels of dabigatran are sufficient to prevent catheter-induced clotting unless supplemented heparin is given.

Enteric Gram-negative bacilli suppress Candida biofilms on Foley urinary catheters.

Mixed Candida-bacterial biofilms in urinary catheters are common in hospitalized patients. (i) The aims of this study were to evaluate, quantitatively and qualitatively, the in vitro development of mono- and dual-species biofilms (MSBs and DSBs) of Candida albicans and two enteric gram-negative bacilli (EGNB; Pseudomonas aeruginosa or Escherichia coli) on Foley catheter (FC) discs, (ii) to determine the biofilm growth in tryptic soy broth or glucose supplemented artificial urine (AU) and (iii) to assess the inhibitory effects of EGNB and their lipopolysaccharides (LPS) on Candida biofilm growth. The growth of MSBs and DSBs on FC discs was monitored by cell counts and SEM. The metabolic activity of LPS-treated Candida biofilms was determined by the XTT reduction assay. Candida albicans and EGNB demonstrated significant inter- and intra-species differences in biofilm growth on FC discs (p < 0.01). Pseudomonas aeruginosa suppressed Candida albicans significantly (p < 0.001) in DSBs. Compared with MSBs, DSB of EGNB in glucose supplemented AU demonstrated robust growth. Escherichia coli and its LPS, significantly suppressed Candida biofilm growth, compared with Pseudomonas aeruginosa and its LPS (p < 0.001). Candida albicans and EGNB colonization in FC is significantly increased in AU with glucose, and variably modified by Escherichia coli, Pseudomonas aeruginosa and their corresponding LPS.

Fluconazole resistance in Candida glabrata is associated with increased bud formation and metallothionein production.

Virulence associated with fluconazole (FL) resistance in Candida glabrata is a global problem and has not been well characterized at the proteome level. In this study, a stable FL-resistant (MIC >256 µg ml(-1)) strain of C. glabrata was generated on agar containing FL. Eight phenotypic mutants were characterized by contour-clamped homogeneous electrophoretic field analysis and two-dimensional PAGE. The secondary derivatives of C. glabrata yielded four distinct genotypes with varying chromosomal profiles. Proteomic analysis performed by tandem mass spectrometry for two of the mutants, CG(L2) and CG(S3), demonstrated a total of 25 differentially regulated proteins of which 13 were upregulated and 12 were downregulated or were similar compared with the parental isolate. The mRNA transcript levels of significantly (P<0.001) upregulated genes were determined by quantitative RT-PCR analysis, and their physiological relevance in terms of phenotypic expression of virulence attributes was verified by conventional laboratory methodologies. The data showed that the FL resistance (MIC >256 µg ml(-1)) of CG(S3) was associated with significantly upregulated (P<0.001) mRNA transcript levels of several genes - ERG11, CDR1, CDR2, MFS, MTI, TPR, VPS and EFT2 - in addition to a number of other potentially virulent genes expressed differentially at a lower level. The results demonstrated accentuated phenotypic expression of bud formation of yeast and metallothionein production associated with FL resistance in C. glabrata, which may help the fungus to colonize the host.

Prosthetic valve endocarditis: what is the evidence for anticoagulant therapy?

The use of anticoagulant therapy in prosthetic valve endocarditis is a controversial management issue. Some authorities believe that anticoagulation increases the potential risk of cerebral haemorrhage after a thromboembolism whereas others, however, affirm that cessation of anticoagulation itself increases the risk of thromboembolism and subsequent morbidity and mortality. We reviewed the association of anticoagulant therapy and cerebral complications in patients with prosthetic valve endocarditis. Our results suggest that anticoagulant therapy reduces the risk of thromboembolism and is not associated with increased risk of intracranial haemorrhage.

A synopsis of current care of thalassaemia major patients in Hong Kong.

OBJECTIVE: To provide a synopsis of current thalassaemia major patient care in Hong Kong. DESIGN: Retrospective study. SETTING: All haematology units of the Hospital Authority in Hong Kong. PATIENTS: All patients with thalassaemia major with regular transfusion. RESULTS: To date, there were 363 thalassaemia major patients under the care of the Hospital Authority. Prenatal diagnosis has helped to reduce the number of indigenous new cases, but in recent years immigrant cases are appearing. The patients have a mean age of 23 (range, 1-52) years, and 78% of them are adults. In 2009, they received 18 782 units of blood. This accounted for 9.5% of all blood consumption from the Hong Kong Red Cross. In the past, cardiac iron overload was the major cause of death (65%) and few patients survived beyond the age of 45 years. The availability of cardiac iron assessment by magnetic resonance imaging (T2 MRI) to direct the use of oral deferiprone chelation has reduced the prevalence of heart failure and cardiac haemosiderosis, which should reduce mortality and improve life expectancy. CONCLUSION: The future for thalassaemia care in Hong Kong is bright. With better transfusion and chelation, it should be possible to avoid growth and endocrine deficiencies in younger patients.

Muscle fatigue and excitation-contraction coupling responses following a session of prolonged cycling.

AIM: The mechanisms underlying the fatigue that occurs in human muscle following sustained activity are thought to reside in one or more of the excitation-contraction coupling (E-C coupling) processes. This study investigated the association between the changes in select E-C coupling properties and the impairment in force generation that occurs with prolonged cycling. METHODS: Ten volunteers with a peak aerobic power (VO(2peak)) of 2.95 ± 0.27 L min(-1) (mean ± SE), exercised for 2 h at 62 ± 1.3%. Quadriceps function was assessed and tissue properties (vastus lateralis) were measured prior to (E1-pre) and following (E1-post) exercise and on three consecutive days of recovery (R1, R2 and R3). RESULTS: While exercise failed to depress the maximal activity (V(max) ) of the Na(+) ,K(+) -ATPase (P = 0.10), reductions (P < 0.05) were found at E1-post in V(max) of sarcoplasmic reticulum Ca(2+) -ATPase (-22%), Ca(2+) -uptake (-26%) and phase 1(-33%) and 2 (-38%) Ca(2+) -release. Both V(max) and Ca(2+) -release (phase 2) recovered by R1, whereas Ca(2+) -uptake and Ca(2+) -release (phase 1) remained depressed (P < 0.05) at R1 and at R1 and R2 and possibly R3 (P < 0.06) respectively. Compared with E1-pre, fatigue was observed (P < 0.05) at 10 Hz electrical stimulation at E1-post (-56%), which persisted throughout recovery. The exercise increased (P < 0.05) overall content of the Na(+), K(+)-ATPase (R1, R2 and R3) and the isoforms ß2 (R1, R2 and R3) and ß3 (R3), but not ß1 or the α-isoforms (α1, α2 and α3). CONCLUSION: These results suggest a possible direct role for Ca(2+)-release in fatigue and demonstrate a single exercise session can induce overlapping perturbations and adaptations (particularly to the Na(+), K(+)-ATPase).

Muscle metabolic, enzymatic and transporter responses to a session of prolonged cycling.

A single session of prolonged work was employed to investigate changes in selected metabolic, transporter and enzymatic properties in muscle. Ten active but untrained volunteers (weight = 73.9 ± 4.2 kg) with a peak aerobic power [Formula: see text] of 2.95 ± 0.27 l min(-1), cycled for 2 h at 62 ± 1.3% [Formula: see text] Tissue extraction from the vastus lateralis occurred prior to (E1-Pre) and following (E1-Post) exercise and on 3 consecutive days of recovery (R1, R2, R3). The exercise resulted in decreases (P < 0.05) in ATP (-9.3%) and creatine phosphate (-49%) and increases in lactate (+100%), calculated free ADP (+253%) and free AMP (+1,207%), all of which recovered to E1-Pre by R1. Glycogen concentration, which was depressed (P < 0.05) by 75% at E1-Post, did not recover until R3. Compared to E1-Pre, the cycling also resulted in decreases (P < 0.05) in the activities of cytochrome c oxidase, phosphorylase, and hexokinase but not in citrate synthase (CS) or 3-hydroxy-CoA dehydrogenase at E1-Post. With the exception of CS, which was elevated (P < 0.05) at R3, all enzyme activities were not different from E1-Pre during recovery. For the glucose (GLUT1, GLUT4) and monocarboxylate (MCT1, MCT4) transporters, changes in expression levels (P < 0.05) were only observed for GLUT1 at R1 (+42%) and R3 (+33%). It is concluded that the metabolic stress produced by prolonged exercise is reversed by 1 day of recovery. One day of exercise also resulted in a potential upregulation in the citric acid cycle and glucose transport capabilities, adaptations which are expressed at variable recovery durations.

Retinal fractal dimension is increased in persons with diabetes but not impaired glucose metabolism: the Australian Diabetes, Obesity and Lifestyle (AusDiab) study.

AIMS/HYPOTHESIS: The fractal dimension (D(f)) of the retinal vasculature is a global measure of its branching pattern complexity. We examined the relationship of retinal D(f) with diabetes. METHODS: We conducted a cross-sectional study of 1,577 participants with diabetes and impaired glucose metabolism and normal controls from the population-based Australian Diabetes, Obesity and Lifestyle (AusDiab) study. Retinal D(f) was quantified from fundus photographs using a computer-based programme and diabetes status was determined by oral glucose tolerance test based on the WHO criteria. RESULTS: After adjustment for age, sex and vascular risk factors, persons with higher retinal D(f) were more likely to have diabetes (OR 1.56; 95% CI 1.14-2.14, highest vs lowest fractal tertile). This relationship remained with further adjustment for retinal arteriolar calibre and presence of retinopathy (OR 1.64; 95% CI 1.19-2.27), and after excluding participants with retinopathy (OR 1.60; 95% CI 1.16-2.21). Retinal D (f) was not related to impaired glucose tolerance or impaired fasting glucose (OR 1.19; 95% CI 0.85-1.67). CONCLUSIONS/INTERPRETATION: Individuals with diabetes, but not with impaired glucose metabolism, have greater retinal D(f), reflecting greater complexity of the retinal vasculature. Our findings suggest the presence of early microvascular changes in the retinal vasculature of persons with diabetes, even in the absence of overt retinopathy.

Pseudomonas aeruginosa inhibits in-vitro Candida biofilm development.

BACKGROUND: Elucidation of the communal behavior of microbes in mixed species biofilms may have a major impact on understanding infectious diseases and for the therapeutics. Although, the structure and the properties of monospecies biofilms and their role in disease have been extensively studied during the last decade, the interactions within mixed biofilms consisting of bacteria and fungi such as Candida spp. have not been illustrated in depth. Hence, the aim of this study was to evaluate the interspecies interactions of Pseudomonas aeruginosa and six different species of Candida comprising C. albicans, C. glabrata, C. krusei, C. tropicalis, C. parapsilosis, and C. dubliniensis in dual species biofilm development. RESULTS: A significant reduction in colony forming units (CFU) of C. parapsilosis (90 min), C. albicans and C. tropicalis (90 min, 24 h and 48 h), C. dubliniensis and C. glabrata, (24 h and 48 h) was noted when co-cultured with P. aeruginosa in comparison to their monospecies counterparts (P < 0.05). A simultaneous significant reduction in P. aeruginosa numbers grown with C. albicans (90 min and 48 h), C. krusei (90 min, 24 h and 48 h),C. glabrata, (24 h and 48 h), and an elevation of P. aeruginosa numbers co-cultured with C. tropicalis (48 h) was noted (P < 0.05). When data from all Candida spp. and P. aeruginosa were pooled, highly significant mutual inhibition of biofilm formation was noted (Candida P < 0.001, P. aeruginosa P < 0.01). Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM) analyses confirmed scanty architecture in dual species biofilm in spite of dense colonization in monospecies counterparts. CONCLUSIONS: P. aeruginosa and Candida in a dual species environment mutually suppress biofilm development, both quantitatively and qualitatively. These findings provide a foundation to clarify the molecular basis of bacterial-fungal interactions, and to understand the pathobiology of mixed bacterial-fungal infections.

The post-antifungal effect (PAFE) of amphotericin B, nystatin, ketoconazole and 5-fluorocytosine and its impact on the colonization traits of Candida glabrata.

The post-antifungal effect (PAFE) has been shown to affect Candida pathogenicity, but there is little information on either PAFE or its association with the colonization traits of Candida glabrata. The objective of this study was to determine, in vitro, the PAFE on 14 C. glabrata isolates following exposure to amphotericin B (AMB), nystatin (NYS), ketoconazole (KETO) and 5-fluorocytosine (5FC). In addition, we evaluated the impact of PAFE on yeast adherence to buccal epithelial cells (BEC), cell-surface-hydrophobicity (CSH) and biofilm growth (BG) on denture acrylic surfaces. PAFE was induced following a 1-h exposure of yeasts to (x1-x4MIC) of AMB, NYS, KETO and 5FC in RPMI medium and, measured using automated turbidometry. The BEC adhesion, CSH and BG assays were performed by the methods of Kimura & Pearsall, Sweet et al., and Jin et al., respectively. Significant differences in PAFE (P < 0.001) were observed after exposure to AMB and NYS, but not KETO and 5FC. Following exposure to AMB, NYS, KETO and 5FC, significant inter-strain differences (P < 0.001) were observed in percentage terms in adhesion (39.0%, 43.48%, 38.28%, 35.07%) and biofilm growth (42.86%, 39.86%, 42.81%, 36.38%), respectively. Short exposure of C. glabrata to sub-cidal concentrations of antifungals modulates yeast growth and also affects some of their colonization traits.

Plasminogen activator inhibitor-1 (PAI-1) activity and retinal vascular calibre in type 2 diabetes.

OBJECTIVE: To describe relationships of retinal vascular calibre with plasminogen activator inhibitor-1 (PAI-1) and other cardiovascular risk factors in people with type 2 diabetes. METHODS: We recruited 112 community-based persons aged 44-83years with type 2 diabetes, photo-documented retinal status using a digital fundus camera, and measured traditional and novel vascular risk factors. Retinal arteriolar and venular calibre and the arterio-venous ratio (AVR) were determined from fundus photographs using a validated computer-assisted method. RESULTS: In adjusted linear regression models, PAI-1 activity was strongly associated with all measures of retinal vascular calibre: positively with arterioles (p=0.005) and AVR (p=0.001), and inversely with venules (p=0.001). In addition, wider arterioles were independently associated with waist-hip ratio (p<0.0001), HDL-C (p=0.015), and lower systolic blood pressure (p=0.042), whereas narrower venules were associated with older age and a higher albumin excretion rate. Neither arteriolar nor venular calibre was associated with plasma total homocysteine or C-reactive protein concentration. CONCLUSION: Retinal vascular calibre is independently associated with PAI-1 activity in type 2 diabetes. This finding supports a role for PAI-1 activity in the microvasculature of persons with type 2 diabetes and may explain the link between retinal vascular calibre and cardiovascular disease.

Escherichia coli and its lipopolysaccharide modulate in vitro Candida biofilm formation.

Demystification of microbial behaviour in mixed biofilms could have a major impact on our understanding of infectious diseases. The objectives of this study were to evaluate in vitro the interactions of six different Candida species and a Gram-negative coliform, Escherichia coli, in dual-species biofilms, and to assess the effect of E. coli LPS on Candida biofilm formation. A single isolate of E. coli ATCC 25922 and six different species of Candida, 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, were studied using a standard biofilm assay. Each Candida species was co-cultured with E. coli on a polystyrene surface and biofilm formation was quantified by a c.f.u. assay. The biofilm was then analysed by Live/Dead staining and fluorescence microscopy (confocal laser-scanning microscopy, CLSM), whilst scanning electron microscopy (SEM) was employed to visualize the biofilm architecture. The effect of E. coli LPS on Candida biofilm cell activity at defined time intervals was assessed with an XTT reduction assay. A significant quantitative reduction in c.f.u. counts of C. tropicalis (after 90 min), C. parapsilosis (after 90 min and 24 h), C. krusei (after 24 h) and C. dubliniensis (after 24 and 48 h) was noted on incubation with E. coli in comparison with their monospecies biofilm counterparts (P <0.05). On the other hand, a simultaneous and significant reduction in E. coli cell numbers occurred on co-culture with C. albicans (after 90 min), and an elevation of E. coli cell numbers followed co-culture with C. tropicalis (after 24 h) and C. dubliniensis (after 24 h and 48 h) (P <0.05). All quantitative findings were confirmed by SEM and CLSM analyses. By SEM observation, dual-species biofilms demonstrated scanty architecture with reduced visible cell counts at all stages of biofilm development, despite profuse growth and dense colonization in their single-species counterparts. Significantly elevated metabolic activity, as assessed by XTT readings, was observed in E. coli LPS-treated C. tropicalis and C. parapsilosis biofilms (after 48 h), whilst this had the opposite effect for C. dubliniensis (after 24 h) (P <0.05). These data indicate that E. coli and Candida species in a mixed-species environment mutually modulate biofilm development, both quantitatively and qualitatively, and that E. coli LPS appears to be a key component in mediating these outcomes.