Common infections in diabetes: pathogenesis, management and relationship to glycaemic control

Proof of concept for the role of glycemic control in the early detection of infections in diabetics

The relationship of infections and glycemic control in diabetes has been previously investigated but no solid findings have been described. Meanwhile, the detection of any infection at the early stages of disease progression, i.e. during the incubation period, is critical. In order to study this topic, we used the infection evidence and the daily glycemic control data of 248 type-2 diabetics who participated in a large telemedicine study. The results showed that morning blood glucose was significantly elevated and that diabetics performed the measurements at a later time when infected. A simple model for predicting the occurrence of infection based on the glycemic control variables showed good performance (sensitivity: 56%, specificity: 92%). A set of variables that synthesize a diabetic's profile could be included in a dedicated model and facilitate the early detection of infections; other aspects, such as continuous self-monitoring and personalized medical records, should be examined in this direction.

Impaired function of antibodies to pneumococcal surface protein A but not to capsular polysaccharide in Mexican American adults with type 2 diabetes mellitus

The goal of the study was to determine baseline protective titers of antibodies to Streptococcus pneumoniae surface protein A (PspA) and capsular polysaccharide in individuals with and individuals without type 2 diabetes mellitus. A total of 561 individuals (131 individuals with diabetes and 491 without) were screened for antibodies to PspA using a standard enzyme-linked immunosorbent assay (ELISA). A subset of participants with antibodies to PspA were retested using a WHO ELISA to determine titers of antibodies to capsular polysaccharide (CPS) (serotypes 4, 6B, 9V, 14, 18C, 19A, 19F, and 23F). Functional activity of antibodies was measured by assessing their ability to enhance complement (C3) deposition on pneumococci and promote killing of opsonized pneumococci. Titers of antibodies to protein antigens (PspA) were significantly lower in individuals with diabetes than controls without diabetes (P = 0.01), and antibodies showed a significantly reduced complement deposition ability (P = 0.02). Both antibody titers and complement deposition were negatively associated with hyperglycemia. Conversely, titers of antibodies to capsular polysaccharides were either comparable between the two groups or were significantly higher in individuals with diabetes, as was observed for CPS 14 (P = 0.05). The plasma specimens from individuals with diabetes also demonstrated a higher opsonophagocytic index against CPS serotype 14. Although we demonstrate comparable protective titers of antibodies to CPS in individuals with and individuals without diabetes, those with diabetes had lower PspA titers and poor opsonic activity strongly associated with hyperglycemia. These results suggest a link between diabetes and impairment of antibody response.

Neutrophil dysfunction induced by hyperglycemia: modulation of myeloperoxidase activity

Our data suggest that impaired activity of myeloperoxidase (MPO) may play an important role in the dysfunction of neutrophils from hyperglycemic rats. Neutrophil biochemical pathways include the NADPH oxidase system and the MPO enzyme. They both play important role in the killing function of neutrophils. The effect of hyperglycemia on the activity of these enzymes and the consequences with regard to Candida albicans phagocytosis and the microbicidal property of rat peritoneal neutrophils is evaluated here. The NADPH oxidase system activity was measured using chemiluminescence and cytochrome C reduction assays. MPO activity was measured by monitoring HOCl production, and MPO protein expression was analysed using Western blot and immunofluorescence. C. albicans phagocytosis and death were evaluated by optical microscopy using the May-Grunwald-Giemsa staining method. ROS generation kinetic was slightly delayed in the diabetic group. MPO expression levels were higher in diabetic neutrophils; however, MPO activity was decreased in these same neutrophils compared with the controls. C. albicans phagocytosis and killing were lower in the diabetic neutrophils. Based on our experimental model, the phagocytic and killing functions of neutrophil phagocytosis are impaired in diabetic rats because of the decreased production of HOCl, highlighting the importance of MPO in the microbicidal function of neutrophils.

Bacterial characteristics and glycemic control in diabetic patients with Escherichia coli urinary tract infection

BACKGROUND

Patients with diabetes mellitus have an increased risk of infection. The roles of bacterial characteristics and glycemic control in diabetic patients with Escherichia coli infection have not been well investigated. The aims of this study were to examine the bacterial characteristics and glycemic control in diabetic patients with E. coli infections arising in the urinary tract.

METHODS

A total of 271 E. coli isolates were collected from urine and bloodstream. Phylogenetic groups, the presence of virulence genes, and antimicrobial susceptibility of E. coli isolates were determined.

RESULTS

There were few differences in E. coli bacterial characteristics between 190 diabetic and 81 nondiabetic patients. In diabetic patients with urosepsis, there was a higher hemoglobin A(1C) level, and the related E. coli strains had more neuA, papG II, afa and hlyA genes, and a lower prevalence of antimicrobial resistance to cephalosporins and fluoroquinolones than those with asymptomatic bacteriuria and urinary tract infection. Multivariate logistic regression analysis revealed that increased hemoglobin A(1C) and presence of papG II and afa genes were independent factors associated with development of urosepsis in diabetic patients.

CONCLUSION

This study demonstrated that more virulent E. coli isolates, especially with papG II and afa genes, and poorer glycemic control were important determinants for development of urosepsis in diabetic patients.

Infections in patients with diabetes mellitus: A review of pathogenesis

In general, infectious diseases are more frequent and/or serious in patients with diabetes mellitus, which potentially increases their morbimortality. The greater frequency of infections in diabetic patients is caused by the hyperglycemic environment that favors immune dysfunction (e.g., damage to the neutrophil function, depression of the antioxidant system, and humoral immunity), micro- and macro-angiopathies, neuropathy, decrease in the antibacterial activity of urine, gastrointestinal and urinary dysmotility, and greater number of medical interventions in these patients. The infections affect all organs and systems. Some of these problems are seen mostly in diabetic people, such as foot infections, malignant external otitis, rhinocerebral mucormycosis, and gangrenous cholecystitis. In addition to the increased morbidity, infectious processes may be the first manifestation of diabetes mellitus or the precipitating factors for complications inherent to the disease, such as diabetic ketoacidosis and hypoglycemia. Immunization with anti-pneumococcal and influenza vaccines is recommended to reduce hospitalizations, deaths, and medical expenses.

Erythrocyte mechanical fragility is increased in patients with type 2 diabetes

BACKGROUND

Anemia is common among patients with type 2 diabetes. We determined whether type 2 diabetic patients significantly differed in erythrocyte mechanical fragility as compared with nondiabetic subjects.

METHODS

We recruited 25 Caucasian patients with type 2 diabetes (14 men and 11 women; mean age 58±8 years) and 25 age-, race- and sex-matched nondiabetic individuals. The fragility of erythrocytes was tested by inducing mechanical hemolysis by double aspiration of K(2)EDTA blood through a 0.5 mL insulin syringe equipped with a very thin needle. The plasma was then separated from the blood cells by centrifugation at 2000 xg for 15 min at room temperature. A Beckman Coulter DxC 800 was used to measure the hemolysis index by direct spectrophotometry.

RESULTS

Compared with matched nondiabetic controls, type 2 diabetic patients had a significantly increased mechanical fragility of erythrocytes (hemolysis index ratio 21±13 vs. 14±10, p=0.02). Univariable linear regression analysis revealed that there was a strong positive association between percent hemolysis and fasting plasma glucose (r=0.669, p<0.001) and hemoglobin A1c (r=0.549, p<0.005) in type 2 diabetic subjects, but not in matched nondiabetic controls.

CONCLUSIONS

Our data suggest that patients with type 2 diabetes have a significantly higher erythrocyte mechanical fragility than matched nondiabetic subjects, and that fasting plasma glucose is the strongest correlate of increased mechanical fragility of erythrocytes in this patients group.

What the radiologist needs to know about the diabetic patient

Diabetes mellitus (DM) is recognised as a major health problem. Ninety-nine percent of diabetics suffer from type 2 DM and 10% from type 1 and other types of DM. The number of diabetic patients worldwide is expected to reach 380 millions over the next 15 years. The duration of diabetes is an important factor in the pathogenesis of complications, but other factors frequently coexisting with type 2 DM, such as hypertension, obesity and dyslipidaemia, also contribute to the development of diabetic angiopathy. Microvascular complications include retinopathy, nephropathy and neuropathy. Macroangiopathy mainly affects coronary arteries, carotid arteries and arteries of the lower extremities. Eighty percent of deaths in the diabetic population result from cardiovascular incidents. DM is considered an equivalent of coronary heart disease (CHD). Stroke and peripheral artery disease (PAD) are other main manifestations of diabetic macroangiopathy. Diabetic cardiomyopathy (DC) represents another chronic complication that occurs independently of CHD and hypertension. The greater susceptibility of diabetic patients to infections completes the spectrum of the main consequences of DM. The serious complications of DM make it essential for physicians to be aware of the screening guidelines, allowing for earlier patient diagnosis and treatment.

Diabetes, glycemic control, and risk of tuberculosis: a population-based case-control study

OBJECTIVE

To examine the association between diabetes, glycemic control, and risk of tuberculosis (TB).

RESEARCH DESIGN AND METHODS

We conducted a population-based case-control study in Northern Denmark. Cases of active TB were all individuals with a first-time principal hospital diagnosis of TB between 1980 and 2008. Each case subject was matched with up to five population control subjects with similar age, sex, place and length of residence in Denmark, and country of emigration. We computed odds ratios (ORs) for a first-time TB diagnosis among people with and without diabetes using regression to control for other comorbidities, alcoholism, immunosuppressive medications, and socioeconomic markers.

RESULTS

We identified 2,950 patients, including 156 diabetic individuals (5.3%), with active TB, and 14,274 population control subjects, of which 539 had diabetes (3.8%). The adjusted OR for active TB among subjects with diabetes was 1.18 (95% CI 0.96-1.45) compared with nondiabetic individuals. We found a similar risk increase from diabetes in the 843 (29%) TB case subjects who were immigrants; adjusted OR = 1.23 (95% CI 0.78-1.93). In a subset with laboratory data, diabetic individuals with an HbA(1c) <7.0, 7-7.9, and ≥8.0% had ORs of 0.91 (0.51-1.63), 1.05 (0.41-2.66), and 1.19 (CI 0.61-2.30), respectively, compared with individuals without diabetes.

CONCLUSIONS

In the low TB-burden country of Denmark, the TB risk increase associated with diabetes is substantially lower than previously suggested. We found no evidence for any association between TB and dysglycemia.

Enhanced iron availability by protein glycation may explain higher infection rates in diabetics

Serum proteins exist in a state of higher glycation among individuals with poor glycemic control, notably diabetics. These non-enzymatic modifications via the Maillard reaction have far reaching effects on metabolism and regulation, and may be responsible for increased infection rates within this population. Here we explore the effects of glycation on iron metabolism and innate immunity by investigating the interaction between siderophores and bovine serum albumin (BSA). Using a quartz crystal microbalance with dissipation monitoring to quantify association rates, glycated BSA exhibited a significantly reduced affinity for apo and holo enterobactin compared to a non-glycated BSA standard. Bacterial growth assays in the presence of BSA and under iron-limited conditions indicated the growth rate of enterobactin-producing E. coli increased significantly when the BSA was in a glycated form. The results, in addition to data in the literature, support the hypothesis that glycation of serum proteins may effectively increase the available free iron pool for bacteria in blood serum and weaken our innate immunity. This phenomenon may be partially responsible for higher infection rates in some diabetics, especially those with poor glycemic control.

Looking through the cracks of diabetic candidal balanoposthitis!

India is becoming an epicentre of type II diabetes mellitus with a crude prevalence rate of about 9%. Candida balanoposthitis is a known feature of diabetes mellitus especially in Indian males who are predominantly uncircumcised. In this country, diabetes is often diagnosed for the first time by dermatologists. Diabetes is much more frequently the cause of candida balanoposthitis than sexual intercourse in India. Fissuring along with balanoposthitis was found to be more common in sexually active males. The biomechanical basis of fissuring and the effect of diabetes in this phenomenon are explained. The issue of circumcision is debated under various aspects.

The in vitro effects of advanced glycation end products on basophil functions

BACKGROUND

Basophils are thought to play pivotal roles in the pathogenesis of allergic reactions, but their roles in inflammation associated with systemic abnormalities such as metabolic disorders remain largely unknown. Advanced glycation end products (AGEs) are potentially important substances produced in high-glucose disease conditions. In this in vitro study, we investigated whether the biological functions of human basophils can be influenced by AGEs.

METHODS

We analyzed the effects of AGEs on various functions and markers of human basophils, including CD11b expression, apoptosis, degranulation, and cytokine production.

RESULTS

Flow cytometric analysis indicated that the level of the receptor for AGEs (RAGE) on the surface of freshly isolated basophils was very low but was clearly upregulated by IL-3. Apoptosis of basophils was induced by high concentrations of glycated albumin. Although glycated albumin failed to affect the level of surface CD11b expression or to trigger degranulation or production of IL-4 and IL-13 in basophils, it dose-dependently induced IL-6 and IL-8 secretion.

CONCLUSIONS

AGEs seem to act on human basophils; they suppress the cells' longevity but elicit secretion of inflammatory cytokines. Through these biological changes, basophils might play some roles in inflammatory conditions associated with metabolic disorders presenting elevated levels of AGEs.

The mechanism of protracted wound healing on oral mucosa in diabetes. Review

Diabetic patients increase their body's susceptibility to infection and diabetes is a risk factor for periodontal diseases and oral infection. Although many studies showed the mechanism of impaired wound healing in diabetes, there are still arguments to shed light on what kind of factors, including local and systemic factors are involved in the protracted wound healing. This review article summarizes reports on the wound healing in diabetes and discusses the mechanism of the protracted wound healing of the oral mucosa in diabetes. Delayed vascularization, reduction in blood flow, decline in innate immunity, decreases in growth factor production, and psychological stresses may be involved in the protracted wound healing of the oral mucosa in diabetics.

Change from oral antidiabetic therapy to insulin and risk of urinary tract infections in Type 2 diabetic patients: a population-based prescription study

BACKGROUND

Diabetes is a risk factor for urinary tract infections (UTI), but the impact of insulin treatment and glycaemic control on UTI risk is not clear.

METHODS

We determined the risk of antibiotic-treated UTI episodes in a population-based cohort of 2737 Type 2 diabetic patients who switched from oral antidiabetic drug (OAD) to insulin therapy. Each patient was observed for 365 days before and after the switch date, excluding a 120-day time window around this date. Episodes of UTI were defined as filled prescriptions for a UTI-specific antibiotic. We used conditional logistic regression to estimate the relative risk (odds ratio) of having one or more UTIs in the insulin vs. OAD period overall and stratified by glycaemic change.

RESULTS

After the switch to insulin, 53% of all patients experienced a decrease in individual mean hemoglobin A1c (median decrease=1.5%, interquartile range 0.9%-2.3%). Episodes of treated UTIs occurred in 446 (16.3%) Type 2 diabetic patients in the insulin period and 437 (16.0%) in the OAD period (relative risk 1.04, 95% CI 0.86-1.26). Stratified analyses showed no consistent association between levels of glycaemic improvement and decreased UTI risk during insulin treatment.

CONCLUSIONS

Among patients with Type 2 diabetes, no evidence was found that switch to insulin therapy with or without tightened glycaemic control decreased their high annual risk of antibiotic-treated UTI episodes.

Possible involvement of stress hormones and hyperglycaemia in chronic mild stress-induced impairment of immune functions in diabetic mice

Stress, an important aspect of modern life, has long been associated with an altered homeostatic state. Little is known about the effect of the life stress on the outcome of diabetes mellitus, especially related to the higher risk of infections. Here, we evaluate the effects of chronic mild stress (CMS) exposure on the evolution of type I diabetes induced by streptozotocin administration in BALB/c mice. Exposure of diabetic mice to CMS resulted in a significant reduction of survival and a sustained increase in blood glucose values. Concerning the immune response, chronic stress had a differential effect in mice with diabetes with respect to controls, showing a marked decrease in both T- and B-cell proliferation. No correlation was found between splenic catecholamine or circulating corticosterone levels and the proliferative response. However, a significant negative correlation was found between glucose levels and concanavalin A- and lipopolysaccharide-stimulated proliferative responses of T and B cells. A positive correlation between blood glucose and splenic catecholamine concentrations was found in diabetic mice but not in controls subjected to CMS. Hence, the present report shows that diabetic mice show a worse performance in immune function after stress exposure, pointing to the importance of considering life stress as a risk factor for patients with diabetes.

Risk of revision of a total hip replacement in patients with diabetes mellitus: a population-based follow up study

We have evaluated the extent to which diabetes affects the revision rate following total hip replacement (THR). Through the Danish Hip Arthroplasty Registry we identified all patients undergoing a primary THR (n = 57 575) between 1 January 1996 and 31 December 2005, of whom 3278 had diabetes. The presence of diabetes among these patients was identified through the Danish National Registry of Patients and the Danish National Drug Prescription Database. We estimated the relative risk for revision and the 95% confidence intervals for patients with diabetes compared to those without, adjusting for the confounding factors. Diabetes is associated with an increased risk of revision due to deep infection (relative risk = 1.45 (95% confidence interval 1.00 to 2.09), particularly in those with type 2 diabetes (relative risk = 1.49 (95% confidence interval 1.02 to 2.18)), those with diabetes for less than five years prior to THR (relative risk = 1.69 (95% confidence interval 1.24 to 2.32)), those with complications due to diabetes (relative risk = 2.11 (95% confidence interval 1.41 to 3.17)), and those with cardiovascular comorbidities prior to surgery (relative risk = 2.35 (95% confidence interval 1.39 to 3.98)). Patients and surgeons should be aware of the relatively elevated risk of revision due to deep infection following THR in diabetes particularly in those with insufficient control of their glucose level.

Anesthetic considerations in diabetic patients. Part II: intraoperative and postoperative management of patients with diabetes mellitus

Some studies have reported that tight glycemic control in diabetic patients undergoing major surgery improves perioperative morbidity and mortality rates. Recently, however, large randomized studies have shown such control increases the mortality rate, since aggressive glycemic control induces more frequent incidences of hypoglycemia. Diabetic patients have cerebral complications during the perioperative period more often than their nondiabetic counterparts. Further, anesthetic agents have some effects on cerebral circulation and cerebrovascular carbon dioxide reactivity. Hence, anesthesiologists should have adequate knowledge about anesthetic agents that maintain the integrity of the cerebral circulation. Patients with diabetes mellitus (DM) have an increased susceptibility to perioperative infections. Recent work confirmed that a combination of intravenous and subcutaneous insulin as a glucose management strategy had beneficial effects identical with intravenous insulin therapy alone on the reduction of infection rates during the postoperative period.

Preoperative hyperglycemia predicts infected total knee replacement

BACKGROUND

Diabetes increases the risk of surgical site infections. In many patients undergoing total knee replacement, however, diabetes has not been diagnosed. The purpose of this study was to analyze the applicability of preoperative screening for hyperglycemia in identifying patients predisposed to infected knee replacement.

METHODS

A recent series of 1565 primary total knee replacements performed due to osteoarthritis in a specialized, publicly funded hospital for joint replacement was reviewed.

RESULTS

Preoperative hyperglycemia was significantly associated with infected knee replacement: during the 1-year follow-up infection occurred in 0.44%, 0.93% and 2.42% of patients with preoperative plasma glucose <6.1 mmol/l (<110 mg/dl), 6.1-6.9 mmol/l (110-125 mg/dl) and > or =7.0 mmol/l (> or =126 mg/dl). In age- and gender-adjusted analysis the patients with the highest glucose levels had a 4-fold risk for infected knee replacement compared to the patients with the lowest glucose. Obesity increased the risk of infected knee replacement, but the effect of hyperglycemia on the infection rates remained significant also after adjustment for body mass index. None of the patients with normal but 2.8% of patients with increased glycosylated hemoglobin (>6.5%) experienced infected knee replacement.

CONCLUSION

Obesity and hyperglycemia associate with a higher risk of infected knee replacement. Preoperative screening of plasma glucose is an efficient way to identify patients in increased risk of infection following primary total knee replacement.

An unusual foreign body as cause of chronic sinusitis: a case report

INTRODUCTION

The presence of a foreign body in the nose is a relatively uncommon occurrence. Many unusual foreign bodies in the nose have been reported in the literature, but no case of a nasal packing occurring as a foreign body in the nasal cavity for a prolonged time has been found.

CASE PRESENTATION

We describe a unique case of the largest foreign body left in situ in the nasal cavity for over 10 years. Our patient was a 71-year-old Caucasian man with diabetes. Because of this, he was at high risk of developing complications from the foreign body and the chronic sinusitis. Amazingly, though, the foreign body had not caused any symptoms on our patient for many years, except for nasal discharge during the last few years. To the best of our knowledge, this is the first case in the literature of such a large intra-nasal foreign body described in an adult without mental illness and without trauma that remained in situ for such a long time.

CONCLUSION

Undoubtedly, even illnesses with no complications could prove difficult for clinicians to diagnose. Clinicians should recognize the underlying causes that are responsible for the symptoms of chronic sinusitis and a unilateral nasal discharge should be assumed to be caused by an intra-nasal foreign body until proven otherwise.

Management of Breast Abscesses in Nonlactating Women

Breast abscess in nonlactating women is a rare clinic-pathological entity. A retrospective analysis of all cases of breast abscesses in nonlactating women in a community teaching hospital from 2000 to 2006 was performed. We analyzed their clinical characteristics, prevalence of diabetes mellitus (DM), surgical and medical management, and clinical outcome. We identified 116 breast abscesses in 98 nonlactating women; 89 per cent of patients were black. At presentation, 63 patients (64%) had a known history of DM and eight patients (8%) had newly diagnosed DM. Patients with DM had an increased length of hospital stay than nondiabetic women ( P < 0.01). Most patients (70%) were treated with incision and drainage and antibiotics with a mean time of abscess resolution of 47 ± 54 days. There was no correlation with breast abscess and smoking history. Glycemic control was suboptimal with 46 per cent of subjects receiving insulin therapy during the hospital stay. We found a high prevalence of DM (72%) in nonlactating women presenting with breast abscess. Diabetic women had a longer hospital stay and longer duration of the abscess compared with the patients without diabetes. Diabetes screening in nonlactating women with breast abscess and intensified glycemic control might improve clinical outcome.

Cervical epidural abscess presenting with Brown-Sequard syndrome in a patient with type 2 diabetes

An 80-year-old woman with type 2 diabetes was admitted due to right-handed muscle weakness. The patient presented with Brown-Sequard syndrome, with complete paralysis of the right lower limb along with a loss of pain and temperature sensations in the left lower limb. Magnetic resonance imaging revealed a cervical epidural abscess, and accompanying edema or inflammation of the right side of the spinal cord at the C5 level. She underwent drainage and evacuation of the spinal abscess, followed by intravenous antibiotic administration. These interventions ameliorated the neurological deficits. The present case suggests the importance of epidural abscess as a rare pathogenetic cause of Brown-Sequard syndrome in type 2 diabetes.

Short- and medium-term survival following coronary artery bypass surgery in British Indo-Asian and white Caucasian individuals: impact of diabetes mellitus

Previous studies have suggested that South Asian (SA) ethnicity is a predictor of poorer outcome after coronary artery bypass grafting (CABG). Our aim was to identify potential reasons for the higher postoperative mortality in SA patients and investigate all these reasons. All individuals undergoing isolated CABG in a tertiary cardiac centre from April 2002 to September 2007. In total, there were 2897 subjects (2623 white subjects; 274 SA subjects) who were included in an observational study showing the effect of ethnicity on the medium-term survival following CABG. Survival at 30 days and survival up to five years (median 2.7 years) were measured. SA subjects undergoing CABG were younger (62+/-9 vs. 66+/-9 years, P<0.001), less obese [body mass index (BMI) 26+/-4 vs. 28+/-4 kg/m(2), P<0.001] and had a higher prevalence of diabetes mellitus (58% vs. 33%, P<0.001) compared with white subjects. Thirty-day mortality was higher in SA subjects (2.6% vs. 1.0%, P=0.02). Non-diabetic SA had similar 30-day mortality, five-year survival and life expectancy compared to non-diabetic white subjects. In contrast, diabetic SA had a higher 30-day mortality (3.8% vs. 1.4%, P=0.01) and worse life expectancy compared to diabetic white subjects. The higher early postoperative mortality observed in SA patients is related to higher incidence of diabetes among them. SA diabetics have a significantly higher postoperative mortality and worse overall life expectancy. Ethnicity per se is not an independent predictor of short- or medium-term survival after CABG.

Identification of an unusual pattern of global gene expression in group B Streptococcus grown in human blood

Because passage of the bacterium to blood is a crucial step in the pathogenesis of many group B Streptococcus (GBS) invasive infections, we recently conducted a whole-genome transcriptome analysis during GBS incubation ex vivo with human blood. In the current work, we sought to analyze in detail the difference in GBS gene expression that occurred in one blood sample (donor A) relative to other blood samples. We incubated GBS strain NEM316 with fresh heparinized human blood obtained from healthy volunteers, and analyzed GBS genome expression and cytokine production. Principal component analysis identified extensive clustering of the transcriptome data among all samples at time 0. In striking contrast, the whole bacterial gene expression in the donor A blood sample was significantly different from the gene expression in all other blood samples studied, both after 30 and 90 min of incubation. More genes were up-regulated in donor A blood relative to the other samples, at 30 min and 90 min. Furthermore, there was significant variation in transcript levels between donor A blood and other blood samples. Notably, genes with the highest transcript levels in donor A blood were those involved in carbohydrate metabolism. We also discovered an unusual production of proinflammatory and immunomodulatory cytokines: MIF, tPAI-1 and IL-1β were produced at higher levels in donor A blood relative to the other blood samples, whereas GM-CSF, TNF-α, IFN-γ, IL-7 and IL-10 remained at lower levels in donor A blood. Potential reasons for our observations are that the immune response of donor A significantly influenced the bacterial transcriptome, or both GBS gene expression and immune response were influenced by the metabolic status of donor A.

Fungal foot infection, cellulitis and diabetes: a review

AIMS

To review the current evidence for the presence of fungal foot infection (tinea pedis and toenail onychomycosis) as a risk factor for the development of cellulitis within the lower limb, particularly for those individuals with diabetes.

METHODS

A structured review of medline, embase and cinahl databases was undertaken to identify publications investigating fungal foot infection as a risk factor for the development of cellulitis.

RESULTS

Sixteen studies were identified. Eight studies adopted a case-control methodology, with the remainder being cross-sectional surveys. The majority of studies established the presence of tinea infection by clinical rather than established microbiological methods. Although the majority of papers suggested a link, only two case-control studies employed microbiological diagnosis to demonstrate that fungal foot infection was a risk for the development of lower limb cellulitis, particularly when infection was located between the toes. There were insufficient data to suggest that fungal foot infection posed an increased risk to patients with diabetes.

CONCLUSION

There is some evidence to suggest that fungal infection of the foot is a factor in the development of lower limb cellulitis, but further robust research is needed to confirm these findings and quantify the risk that fungi pose, particularly to the diabetic foot. Meanwhile, improved surveillance and treatment of tinea infections on the foot by healthcare professionals should be encouraged to reduce potential complications.

Diabetes mellitus and apoptosis: inflammatory cells

Since the early observation that similarities between thyroiditis and insulitis existed, the important role played by inflammation in the development of diabetes has been appreciated. More recently, experiments have shown that inflammation also plays a prominent role in the development of target organ damage arising as complications, with both elements of the innate and the adaptive immune system being involved, and that cytokines contributing to local tissue damage may arise from both infiltrating and resident cells. This review will discuss the experimental evidence that shows that inflammatory cell-mediated apoptosis contributes to target organ damage, from beta cell destruction to both micro- and macro-vascular disease complications, and also how alterations in leukocyte turnover affects immune function.

Risk factors for oral postoperative infection in patients with diabetes

The prevalence of diabetes mellitus in the general population has been increasing sharply. Currently, much is feared but little is known about postoperative complications of oral surgery among persons with diabetes. Existing dental education and practice guidelines cite excess infectious risk among patients with diabetes; however, empiric evidence to support such concerns is lacking. In fact, dentists commonly prescribe antibiotics when dental surgical procedures involve bone. This practice may contribute to the rising problem of microbial resistance and may increase overall healthcare costs. The growing number of dental patients with diabetes warrants strengthening the evidence base to guide their dental care and prevent possible morbid complications.

Prolonged high glucose suppresses phorbol 12-myristate 13-acetate and ionomycin-induced interleukin-2 mRNA expression in Jurkat cells

BACKGROUND

The disturbance of immunological responses is a complication of diabetes mellitus.

METHODS AND RESULTS

We cultured Jurkat cells in 11.1 (normal) and 22.2 mmol/l (high) glucose for 12 weeks and stimulated them with 10 nmol/l phorbol 12-myristate 13-acetate (PMA) and 500 nmol/l ionomycin. RT-PCR revealed that induced interleukin (IL)-2 mRNA expression levels were suppressed in high glucose cultures compared to those in normal glucose. Promoter activities of IL-2, nuclear factor of activated T cells (NFAT), and activator protein-1 (AP-1), after 6 h stimulation with PMA and ionomycin, gradually decreased in high glucose cultures to approximately 20% of those in normal glucose at 12 weeks. The prolonged culture in high glucose increased inducible cAMP early repressor (ICER) II mRNA and protein levels, and overexpression of ICER II dose-dependently suppressed promoter activities of IL-2, NFAT, and AP-1. Moreover, ICER II mRNA expression was transiently induced by stimulation with PMA and ionomycin in normal glucose cultures; however, with high glucose, the induction disappeared.

CONCLUSION

These results indicate that ICER II protein accumulates during prolonged culture in high glucose and suppresses IL-2 mRNA expression in Jurkat cells.

Neutrophil response of anaerobic jump trained diabetic rats

This paper investigated the effect of jump training on blood biochemical parameters and neutrophil responses of diabetic rats. Male Wistar rats were divided into control, trained, diabetic and trained-diabetic groups. Diabetes was induced by i.v. injection of streptozotocin. Jump training consisted of six sets of ten jumps in water with overload of 50% of body mass with 1-min of resting, four times per week during 6 weeks. Plasma glucose, lactate, triacylglycerol and total cholesterol concentrations, differential leukocyte count, phagocytosis and anion superoxide production by neutrophils were evaluated. Diabetes caused hyperglycemia, hypertriacylglycerolemia, and body weight loss. Physical training reversed hypertriacylglycerolemia. Jump training increased phagocytosis and anion superoxide production by blood neutrophils from trained and trained-diabetic rats. Neutrophilia and lymphocytopenia occur in diabetic and trained-diabetic rats. Anaerobic jump training in diabetic rats reduced hypertriacylglycerolemia and increased neutrophil anion superoxide production. Phagocytosis was not altered in trained-diabetic rats.

Impaired immune responses in streptozotocin-induced type I diabetes in mice. Involvement of high glucose

Diabetes is widely believed to predispose to serious infections. However, the mechanisms linking diabetes and immunosuppression are not well defined. One potential mediator of the altered defence mechanisms is hyperglycaemia. It has been identified as the main factor contributing to the development of diseases associated with diabetes mellitus. In this study we analyse the immune response in diabetes and the direct effect of hyperglycaemia on T and B lymphocyte reactivity. Diabetes induced an early decrease in IgG levels in the secondary response. However, both primary responses against a T-cell-dependent or independent antigen were affected after 6 months of diabetes induction. T- and B- cell proliferation was only decreased at this time. To gain insight into the potential mechanisms involved, we evaluated the influence of hyperglycaemia over the immune response. Pre-incubation of lymph node and spleen cells in a high glucose (HG) containing medium led to a significant time- and dose-dependent decrease in T- and B-cell proliferation. This effect was associated with the presence of HG-derived supernatants. Still viable cells after HG exposition were able to improve their proliferative response when cultured with the mitogen in a fresh standard medium. HG diminished cell viability, increased apoptosis and induced oxidative stress in lymphocytes. These results indicate that HG concentrations can directly affect lymphoid cell growth. An increase in oxidative stress would be implicated in this deleterious effect. The possibility that prolonged exposure to pathologically HG concentrations would result in the immunosuppressive state observed in diabetes is also discussed.

Diabetes as a risk factor for herpes zoster infection: results of a population-based study in Israel

BACKGROUND

Studies showed that diabetes mellitus (DM) is often accompanied by impaired cell-mediated immunity, which potentially may increase the risk for infectious diseases, including herpes zoster (HZ). However, data on the relation between DM and HZ are scarce. This case-control study explored the association between DM and HZ.

PATIENTS AND METHODS

This study was nested within a cohort of all members of a large health maintenance organization (HMO) in Israel. Cases totaled 22,294 members who were diagnosed with HZ between 2002 and 2006. Controls (n=88,895) were randomly selected from the remaining HMO population using frequency-matched age, sex, and duration of follow-up. Personal data on history of DM, lymphoma, leukemia, or AIDS, were obtained from computerized medical records.

RESULTS

Adjusted analyses showed that the risk of HZ was associated with history of leukemia, lymphoma, use of steroids or antineoplastic medications, and AIDS, particularly among patients below 45 years of age. In a multivariate analysis, DM was associated with an increased risk of HZ (OR=1.53; 95% CI: 1.44-1.62).

CONCLUSIONS

The data suggest that individuals with DM are at increased risk of HZ. Well-designed cohort studies may help to clarify the nature of this association.

Non-ulcerative skin pathologies of the diabetic foot

Many of the complications of the diabetes are well studied but robust research documenting the cutaneous effects of the disease remains sparse. Various studies have suggested that the majority of patients with diabetes will suffer a skin disorder during the course of their disease and for some, the skin changes may even precede the diagnosis of diabetes. Cutaneous pathology of the diabetic foot and lower leg can arise as a result of the direct or indirect effects of diabetic complications. The most common manifestations include fungal and bacterial skin infection, nail disease and diabetic dermopathy. Other less commonly observed conditions include diabetic bullae, necrobiosis lipoidica diabeticorum (NLD), granuloma annulare and reddening of the soles. For many of the less common disorders, there is little in the way of effective treatment. However, much can be done in the clinical setting in the management of the more common manifestations such as bacterial and fungal infection. Fungal infection, in particular, although relatively inconspicuous, is a very common foot problem and if left untreated can threaten tissue viability in the diabetic foot leading to secondary bacterial infection and cellulitis. Management of fungal disease is often considered difficult due to high relapse and re-infection rates, although by introducing a combination of therapies including mechanical and pharmacological the success in treating this stubborn condition can be greatly improved.

Beta-hydroxybutyrate abrogates formation of bovine neutrophil extracellular traps and bactericidal activity against mammary pathogenic Escherichia coli

Escherichia coli is an important bacterial species isolated from bovine mastitis. The rate of neutrophil recruitment into the mammary gland and their bactericidal activity largely affect the severity and outcome of the disease. Ketosis is a common metabolic disease, and affected dairy cows are known to have increased risk for mastitis and other infectious conditions. The disease is associated with high blood and milk levels of beta-hydroxybutyrate (BHBA), previously shown to negatively affect neutrophil function by unknown mechanisms. We show here that the mammary pathogenic E. coli strain P4 activates normal bovine neutrophils to form neutrophil extracellular traps (NETs), which are highly bactericidal against this organism. Preincubation of these neutrophils with increasing concentrations (0.1 to 8 mmol/liter) of BHBA caused a fivefold decrease of E. coli P4 phagocytosis, though intracellular killing was unaffected. Furthermore, BHBA caused a 10-fold decrease in the NETs formed by E. coli P4-activated neutrophils and a similar decrease in NET bactericidal activity against this organism. These negative effects of BHBA on bovine neutrophils might explain the increased susceptibility of ketotic cows to mastitis and other infectious conditions.

A potent, non-toxic insulin-releasing peptide isolated from an extract of the skin of the Asian frog, Hylarana guntheri (Anura:Ranidae)

Peptides in extract of the skin of the Asian frog Hylarana guntheri Boulenger,1882 were purified by reversed-phase HPLC and individual components analysed for their ability to release insulin from the rat BRIN-BD11 clonal beta cell line. The most potent peptide identified in the extract belonged to the brevinin-2 family (brevinin-2GUb; GVIIDTLKGAAKTVAAELLRKAHCKLTNSC). Other peptides with weaker insulin-releasing activity belonged to the brevinin-1 (2 peptides), brevinin-2 (2 peptides) and temporin (3 peptides) families. Only the brevinin-1 peptides showed cytolytic activity against the BRIN-BD11 cells, as demonstrated by an increased rate of release of the cytosolic enzyme, lactate dehydrogenase. A synthetic replicate of brevinin-2GUb produced a significant stimulation of insulin release (139% of basal rate; P<0.05) at a concentration of 100 nM with a maximum response of 373% of basal rate at a concentration of 3 microM) by a mechanism that did not involve mobilization of intracellular calcium. Brevinin-2GUb also inhibited the growth of microorganisms (MIC against Escherichia coli=32 microM, Staphylococcus aureus=64 microM, and Candida albicans=64 microM) but had only weak hemolytic activity against human erythrocytes (LC(50)=700 microM). Administration of brevinin-2GUb (75 nmol/kg body weight) into mice significantly (P<0.05) improved glucose tolerance following a intraperitoneal injection of glucose, thereby demonstrating that the peptide shows potential for development into a therapeutically valuable agent for the treatment of Type 2 diabetes.

Infections in Diabetes Mellitus and Hyperglycemia

Infections in diabetes mellitus are relatively more common and serious. Diabetic patients run the risk of acute metabolic decompensation during infections, and conversely patients with metabolic decompensation are at higher risk of certain invasive infections. Tight glycemic control is of paramount importance during acute infected or high stress state. Infections in diabetic patients result in extended hospital stays and additional financial burden. Given the risks of not alleviating the metabolic dysregulation and the benefits of decent glycemic control, it is necessary that besides antimicrobial therapy, equal emphasis be placed on intensified glycemic control.