The Impact of Diabetes in Patients with Necrotizing Soft Tissue Infections

Favorable Aspects of Silymarin in Linezolid Treatment Against Diabetic Methicillin-Resistant Staphylococcus aureus (MRSA) Infected Rats

Background:

Linezolid used for diabetic methicillin-resistant Staphylococcus aureus (MRSA) infections is limited due to hepatotoxicity, lactic acidosis, anemia, and oxidative stress induced by diabetes and linezolid therapy. Silymarin is a hepatoprotective, antioxidant, antibacterial, and antidiabetic.

Objective:

The research investigated the role of silymarin in linezolid treatment against MRSA-infected diabetic rats.

Methods:

Type 2 diabetes mellitus (T2DM) was induced by a high-fat diet (58% calories fat) for 2 weeks, followed by a single intraperitoneal injection of streptozotocin (STZ) 35 mg/kg into Wistar rats. The diabetic rats were rendered neutropenic and subcutaneously injected with 106 CFU/ml of MRSA. Linezolid and silymarin were administered orally at a dose of 50 mg/kg twice daily for 14 days. The bacterial load/abscess, hematological, biochemical, enzymatic parameters, antioxidants, and histopathological studies were performed on the 42nd day.

Results:

The MRSA was confirmed by PCR assay. The minimum inhibitory concentration of linezolid was found to be 0.5-2 μg/ml. The linezolid treated MRSA infected diabetic rats showed 9.69 x 103 CFU / abscess bacterial count, decreased intestinal alkaline phosphatase (IAP), RBC, antioxidants, elevated lactate, and liver markers than diabetic rats. The silymarin treatment showed a decrease in the bacterial count (2.98 x 103 CFU / abscess), serum lactate, liver markers, increased IAP levels, and antioxidants in linezolid treated diabetic infected rats.

Conclusion:

The research concluded that silymarin could be a better herbal therapeutic agent that attenuated diabetic and linezolid induced complications in MRSA-infected diabetic rats.

Diabetes-associated infections: development of antimicrobial resistance and possible treatment strategies

Diabetes mellitus is associated with various types of infections notably skin, mucous membrane, soft tissue, urinary tract, respiratory tract and surgical and/or hospital-associated infections. The reason behind this frequent association with infections is an immunocompromised state of diabetic patient because uncontrolled hyperglycemia impairs overall immunity of diabetic patient via involvement of various mechanistic pathways that lead to the diabetic patient as immunocompromised. There are specific microbes that are associated with each type of infection and their presence indicates specific type of infections. For instance, E. coli and Klebsiella are the most common causative pathogens responsible for the development of urinary tract infections. Diabetic-foot infections commonly occur in diabetic patients. In this article, we have mainly focused on the association of diabetes mellitus with various types of bacterial infections and the pattern of resistance against antimicrobial agents that are frequently used for the treatment of diabetes-associated infections. Moreover, we have also summarized the possible treatment strategies against diabetes-associated infections.

Diabetes and necrotizing soft tissue infections-A prospective observational cohort study: Statistical analysis plan

BACKGROUND

Necrotizing soft tissue infections (NSTIs) are rare but carry a high morbidity and mortality. The multicenter INFECT project aims to improve the understanding of the pathogenesis, clinical characteristics, diagnosis, and prognosis of NSTIs. This article describes the study outline and statistical analyses that will be used.

METHODS

Within the framework of INFECT project, patients with NSTI at 5 Scandinavian hospitals are enrolled in a prospective observational cohort study. The goal is to evaluate outcome and characteristics for patients with NSTI and diabetes compared to patients with NSTI without diabetes. The primary outcome is mortality at 90 days after inclusion. Secondary outcomes include days alive and out of ICU and hospital, SAPS II, SOFA score, infectious etiology, amputation, affected body area, and renal replacement therapy. Comparison in mortality between patients with diabetes type 1 and 2 as well as between insulin-treated and non-insulin-treated diabetes patients will be made. Clinical data for diabetic patients with NSTI will be reported.

CONCLUSION

The study will provide important data on patients with NSTI and diabetes.

Pattern and predictors of mortality in necrotizing fasciitis patients in a single tertiary hospital

Background

Necrotizing fasciitis (NF) is a fatal aggressive infectious disease. We aimed to assess the major contributing factors of mortality in NF patients.

Methods

A retrospective study was conducted at a single surgical intensive care unit between 2000 and 2013. Patients were categorized into 2 groups based on their in-hospital outcome (survivors versus non-survivors).

Results

During a14-year period, 331 NF patients were admitted with a mean age of 50.8 ± 15.4 years and 74 % of them were males Non-survivors (26 %) were 14.5 years older (p = 0.001) and had lower frequency of pain (p = 0.01) and fever (p = 0.001) than survivors (74 %) at hospital presentation. Diabetes mellitus, hypertension, and coronary artery disease were more prevalent among non-survivors (p = 0.001). The 2 groups were comparable for the site of infection; except for sacral region that was more involved in non-survivors (p = 0.005). On admission, non-survivors had lower hemoglobin levels (p = 0.001), platelet count (p = 0.02), blood glucose levels (p = 0.07) and had higher serum creatinine (p = 0.001). Non-survivors had greater median LRINEC (Laboratory Risk Indicator for NECrotizing fasciitis score) and Sequential Organ Failure Assessment (SOFA) scores (p = 0.001). Polybacterial and monobacterial gram negative infections were more evident in non-survivors group. Monobacterial pseudomonas (p = 0.01) and proteus infections (p = 0.005) were reported more among non-survivors. The overall mortality was 26 % and the major causes of death were bacteremia, septic shock and multiorgan failure. Multivariate analysis showed that age and SOFA score were independent predictors of mortality in the entire study population.

Conclusion

The mortality rate is quite high as one quarter of NF patients died during hospitalization. The present study highlights the clinical and laboratory characteristics and predictors of mortality in NF patients.

Diabetes and infection: assessing the association with glycaemic control in population-based studies

Diabetes is a leading cause of morbidity and mortality. The global burden of diabetes is rising because of increased obesity and population ageing. Although preventive and treatment measures are well documented for macrovascular and microvascular complications, little such guidance exists for infections in people with diabetes, despite evidence suggesting greater susceptibility to infections, and worse outcomes. In particular, few studies have characterised the relation between glycaemic control and infectious disease, which we discuss in this Review. Some large population-based observational studies have reported strong associations between higher HbA1c and infection risks for both type 1 and type 2 diabetes. However, studies are contradictory, underpowered, or do not control for confounders. Evidence suggests that better glycaemic control might reduce infection risk, but further longitudinal studies with more frequent measures of HbA1c are needed. Older people (aged 70 years or older) with diabetes are at increased risk of complications, including infectious diseases. There is more uncertainty about appropriate glycaemic control targets in this age group, and evidence suggests that glycaemic control is often neglected. Robust evidence from cohorts with sufficient numbers of older people would help to develop clinically relevant guidelines and targets to reduce mortality, morbidity, and antibiotic use, and to improve quality of life.

Necrotizing fasciitis in patients with diabetes mellitus: clinical characteristics and risk factors for mortality

Background

Necrotizing fasciitis (NF) is a rapidly progressive and life-threatening infection. This study aimed to investigate the clinical characteristics and mortality- associated factors in diabetic patients.

Methods

Detailed clinical information of 165 NF cases was retrospectively collected and analyzed in National Taiwan University Hospital between January 1997 and February 2013. We documented and compared the clinical features according to the presence of underlying diabetes mellitus, and we identified risk factors associated with mortality.

Results

There were 84 patients (51 %) with diabetes. The overall case fatality rate was 29.7 %, and we found no significant difference between the patients with or without diabetes. Compared with the nondiabetic patients, diabetic patients were older and exhibited higher serum levels of glucose and potassium on admission. Polymicrobial infection and monomicrobial NF caused by Klebsiella pneumoniae were also more frequently associated with diabetic patients. Moreover, diabetic NF patients exhibit a significantly higher chance of limb loss during hospitalization. In the combined diabetic and nondiabetic cohort, a high serum level of potassium (odds ratio, 2.2; 95 % confidence interval, 1.2 to 4.02; P = 0.011) on admission was independently associated with mortality, whereas positive blood culture on admission was associated with mortality in the diabetic cohort (odds ratio, 7.36; 95 % confidence interval, 1.66 to 32.54; P = 0.009).

Conclusions

Diabetic patients are more susceptible to NF caused by polymicrobial infection or K. pneumoniae, and they are more likely to receive limb amputation for infection control. Bacteraemia on admission is a significant risk factor for mortality in diabetic NF patients.

Prognostic factors in necrotizing soft-tissue infections (NSTI): A cohort study

BACKGROUND

Necrotizing soft-tissue infection (NSTI) is uncommon but life-threatening. A recent meta-analysis estimated the overall mortality at 23.5%.

OBJECTIVE

We sought to identify risk factors associated with mortality in a cohort of patients with NSTI in a tertiary care center.

METHODS

We identified 512 patients with NSTI between 1996 and 2012 in the national hospital database Program for Medicalization of Information Systems and examined risk factors of mortality with NSTI by univariate and multivariate analysis.

RESULTS

We included 109 patients with a confirmed diagnosis of NSTI; 31 (28%) died at a median follow-up of 274 days (range 2-6135 days). On multivariate analysis, independent risk factors of mortality were age older than 75 years (hazard ratio [HR] 4.4, 95% confidence interval [CI] 1.8-10.3), multifocal NSTI (HR 5.9, 95% CI 1.9-18.5), severe peripheral vascular disease (HR 5.1, 95% CI 1.5-17.0), hospital-acquired infection (HR 3.9, 95% CI 1.4-10.7), severe sepsis (HR 7.4, 95% CI 1.7-33.1), and septic shock on hospital admission (HR 13.9, 95% CI 3.8-50.4).

LIMITATIONS

This was a retrospective cohort, which disallows a precise record of the delay between diagnosis and surgery.

CONCLUSION

Our findings for this robust cohort of patients with a definite diagnosis of NSTI could help clinicians stratify NSTI severity at clinical course onset.

Skin and soft tissue infections and associated complications among commercially insured patients aged 0-64 years with and without diabetes in the U.S

Introduction

Skin and soft tissue infections (SSTIs) are common infections occurring in ambulatory and inpatient settings. The extent of complications associated with these infections by diabetes status is not well established.

Methods

Using a very large repository database, we examined medical and pharmacy claims of individuals aged 0–64 between 2005 and 2010 enrolled in U.S. health plans. Diabetes, SSTIs, and SSTI-associated complications were identified by ICD-9 codes. SSTIs were stratified by clinical category and setting of initial diagnosis.

Results

We identified 2,227,401 SSTI episodes, 10% of which occurred in diabetic individuals. Most SSTIs were initially diagnosed in ambulatory settings independent from diabetes status. Abscess/cellulitis was the more common SSTI group in diabetic and non-diabetic individuals (66% and 59%, respectively). There were differences in the frequencies of SSTI categories between diabetic and non-diabetic individuals (p<0.01). Among SSTIs diagnosed in ambulatory settings, the SSTI-associated complication rate was over five times higher in people with diabetes than in people without diabetes (4.9% vs. 0.8%, p<0.01) and SSTI-associated hospitalizations were 4.9% and 1.1% in patients with and without diabetes, respectively. Among SSTIs diagnosed in the inpatient setting, bacteremia/endocarditis/septicemia/sepsis was the most common associated complication occurring in 25% and 16% of SSTIs in patients with and without diabetes, respectively (p<0.01).

Conclusions

Among persons with SSTIs, we found SSTI-associated complications were five times higher and SSTI-associated hospitalizations were four times higher, in patients with diabetes compared to those without diabetes. SSTI prevention efforts in individuals with diabetes may have significant impact on morbidity and healthcare resource utilization.

Post-admission glucose levels are associated with healthcare-associated bloodstream infections and pneumonia in hospitalized patients with diabetes

OBJECTIVE

We conducted a case-control study to examine if short-term glucose control is related to healthcare-associated bloodstream infections (BSI), urinary tract infections (UTI), and pneumonia in hospitalized adults with diabetes.

SETTING AND PATIENTS

We analyzed 205 BSI, 510 UTI, and 109 pneumonia cases and 989, 2463, and 543 controls matched by age, sex and hospital stay seen at a large healthcare system in Manhattan from 2006 to 2008.

METHODS

We examined whether infection risk was associated with serum glucose measured at admission and within 2 days to infection, using conditional logistic regression. Co-morbidities, immunosuppressive medications, prior hospitalizations, and insertion of indwelling devices were considered as potential confounders.

RESULTS

Admission glucose level was not associated with infection. Glucose levels of ≥ 110 mg/dL measured within 2 days to infection were associated with BSI (Odds ratios from 2.04 to 2.67). Glucose level of ≥ 180 mg/dL was associated with pneumonia (Odds ratio=2.30). Decrease in glucose levels from admission to the infection was greater for controls than for infected cases.

CONCLUSION

Healthcare-associated BSI and pneumonia were associated with glucose levels prior to infection diagnosis, but not with glucose levels at admission. Persistently high glucose level could be an indication of an underlying undiagnosed infection.

Necrotizing fasciitis caused by Staphylococcus aureus: the emergence of methicillin-resistant strains

Staphylococcus aureus is an uncommon causative agent of monomicrobial necrotizing fasciitis, but we have noted several cases over the years. The patients treated for necrotizing fasciitis between January 1998 and December 2008 in our institution were identified, and their medical records were reviewed. Of 105 necrotizing fasciitis cases during the study period, 18 were caused by monomicrobial S. aureus infection (17%). The median age was 62 years (range, 12-81 years). Among this cohort, 10 patients had coexisting medical conditions or risk factors, including diabetes and hypertension. Lower limbs and upper limbs are the most commonly involved sites. Among the bacterial isolates from these cases, 8 were methicillin-sensitive S. aureus (MSSA) and 10 were methicillin-resistant S. aureus (MRSA). One patient died in the MSSA group, and 5 patients died in the MRSA group. The mortality rate and other clinical characteristics were not significantly different between the 2 groups. However, all MRSA necrotizing fasciitis developed after the year 2000, and it was significantly different from MSSA necrotizing fasciitis that predominantly took place before the year 2000. In conclusion, S. aureus is an important pathogen of monomicrobial necrotizing fasciitis, and MRSA has emerged as the predominant causative agent in recent years. Therefore, MRSA-directed antibiotic therapy should be considered when treating patients suspected with necrotizing fasciitis in endemic areas.

Hyperbaric oxygen therapy in necrotizing soft tissue infections

BACKGROUND

Surgical debridement and antibiotics are the mainstays of therapy for patients with necrotizing soft tissue infections (NSTIs), but hyperbaric oxygen therapy (HBO) is often used as an adjunctive measure. Despite this, the efficacy of HBO remains unclear. We hypothesized that HBO would have no effect on mortality or amputation rates.

METHODS

We performed a retrospective analysis of our institutional experience from 2005 to 2009. Inclusion criteria were age > 18 y and discharge diagnosis of NSTI. We abstracted baseline demographics, physiology, laboratory values, and operative course from the medical record. The primary endpoint was in-hospital mortality; the secondary endpoint was extremity amputation rate. We compared baseline variables using Mann-Whitney, chi-square, and Fisher's exact test, as appropriate. Significance was set at P < 0.05.

RESULTS

We identified 80 cases over the study period. The cohort was 54% male (n = 43) and 53% white (n = 43), and had a mean age of 55 ± 16 y. There were no significant differences in demographics, physiology, or comorbidities between groups. In-hospital mortality was not different between groups (16% in the HBO group versus 19% in the non-HBO group; P = 0.77). In patients with extremity NSTI, the amputation rate did not differ significantly between patients who did not receive HBO and those who did (17% versus 25%; P = 0.46).

CONCLUSIONS

Hyperbaric oxygen therapy does not appear to decrease in-hospital mortality or amputation rate after in patients with NSTI. There may be a role for HBO in treatment of NSTI; nevertheless, consideration of HBO should never delay operative therapy. Further evidence of efficacy is necessary before HBO can be considered the standard of care in NSTI.

Necrotizing fasciitis following laparoscopic left hemicolectomy for diverticulitis

Necrotizing fasciitis (NF) is a rapidly progressing bacterial infection of soft skin tissue layers, combined with high mortality rates. Association with laparoscopic surgery is rare. In this article, we report a case of a 61-year-old patient suffering from severe NF after laparoscopic left hemicolectomy with low anterior resection due to diverticulitis of sigmoid colon. Skin discolorations, combined with critical illness of the patient, led to the diagnosis of NF. Early recognition, intensive care treatment with stabilization of vital parameters, broad-band antibiotics, and aggressive debridement are the cornerstones for successful treatment of NF.

Skin and soft tissue infections in hospitalised patients with diabetes: culture isolates and risk factors associated with mortality, length of stay and cost

AIMS/HYPOTHESIS

Skin and soft tissue infections (SSTIs) cause substantial morbidity in persons with diabetes. There are few data on pathogens or risk factors associated with important outcomes in diabetic patients hospitalised with SSTIs.

METHODS

Using a clinical research database from CareFusion, we identified 3,030 hospitalised diabetic patients with positive culture isolates and a diagnosis of SSTI in 97 US hospitals between 2003 and 2007. We classified the culture isolates and analysed their association with the anatomic location of infection, mortality, length of stay and hospital costs.

RESULTS

The only culture isolate with a significantly increased prevalence was methicillin-resistant Staphylococcus aureus (MRSA); prevalence for infection of the foot was increased from 11.6 to 21.9% (p < 0.0001) and for non-foot locations from 14.0% to 24.6% (p = 0.006). Patients with non-foot (vs foot) infections were more severely ill at presentation and had higher mortality rates (2.2% vs 1.0%, p < 0.05). Significant independent risk factors associated with higher mortality rates included having a polymicrobial culture with Pseudomonas aeruginosa (OR 3.1), a monomicrobial culture with other gram-negatives (OR 8.9), greater illness severity (OR 1.9) and being transferred from another hospital (OR 5.1). These factors and need for major surgery were also independently associated with longer length of stay and higher costs.

CONCLUSIONS/INTERPRETATION

Among diabetic patients hospitalised with SSTI from 2003 to 2007, only MRSA increased in prevalence. Patients with non-foot (vs foot) infections were more severely ill. Independent risk factors for increased mortality rates, length of stay and costs included more severe illness, transfer from another hospital and wound cultures with Pseudomonas or other gram-negatives.

Predicting death in necrotizing soft tissue infections: a clinical score

BACKGROUND

Necrotizing soft tissue infections (NSTIs) are associated with a high mortality rate; however, there is no uniform way to categorize the severity of this disease early in its course. The goal of this study was to develop a clinical score based on data available at the time of initial assessment to aid in stratifying patients according to their risk of death.

METHODS

A cohort of all 350 patients admitted with NSTI to two institutions over a nine-year period was examined retrospectively. Using random split sampling, two datasets were created: Prediction (PD) and validation (VD). Multivariable stepwise regression analysis of the PD identified independent predictors of death using data available at the time of admission. Model performance was evaluated for accuracy, discrimination, and calibration. A clinical score to predict death was created, and using the Trauma and Injury Severity Score (TRISS) methodology, the score was validated on the VD (z-statistic).

RESULTS

Six admission parameters independently predicted death: Age > 50 years, heart rate > 110 beats/min, temperature <36 degrees C, white blood cell count > 40,000/mcL, serum creatinine concentration > 1.5 mg/dL, and hematocrit > 50%. The accuracy of this model was 86.8%; the area under the receiver-operating characteristic curve was 0.81, and the Hosmer-Lemeshow statistic was 11.8. Additionally, the score had excellent performance in evaluation on the VD (z-score/statistic 0.23 to - 0.83).

CONCLUSION

A clinical score that categorizes patients with NSTI according to the risk of death was created. It uses simple variables, all available at the time of first assessment. It stratifies patients according to disease severity and can guide the use of aggressive or novel therapeutic strategies and selection of patients for clinical trials.

Skin and soft tissue infections

Skin and soft tissue infections are a common cause of hospitalization and use of antibiotic therapy, and may result in significant disability. Infections managed by surgeons may vary from simple, noncomplicated cellulitis to severe necrotizing soft tissue infections. The differentiation of necrotizing infections from nonnecrotizing infections is critical to achieving adequate surgical therapy. An understanding of the changing epidemiology of all complicated skin and soft tissue infections is required for selection of appropriate empiric antibiotic therapy.

Necrotizing soft tissue infections

PURPOSE OF REVIEW

The purpose of this review is to consider recent advances in the definition, pathogenesis, diagnostic criteria, and treatment of necrotizing soft tissue infections.

RECENT FINDINGS

The efficacy of early surgical debridement combined with antimicrobial therapy, close monitoring and physiologic support is strongly demonstrated. Novel therapeutic strategies including vacuum-assisted wound-closure therapy and intravenous immunoglobulin have been described.

SUMMARY

Necrotizing soft-tissue infection is a rare infection of the subcutaneous tissue and fascia that is often associated with sepsis and can progress rapidly with a possible fatal outcome. Although the cause is not yet understood fully, patients often have a prior history of a small, trivial trauma, wound, or scratch. Establishing the diagnosis can be the main challenge in treating patients, and knowledge of all available tools is key for early and accurate diagnosis.

Correlates of length of stay, cost of care, and mortality among patients hospitalized for necrotizing fasciitis

Several previous studies of necrotizing fasciitis (NF) have been single-institution investigations suffering from small samples sizes. This study of 216 NF patients hospitalized in Florida, USA, during 2001 was designed to identify risk factors for length of stay (LOS), total patient charges (TC), and mortality, using a statewide database. Robust gamma mixed regression was used to determine the predictors of LOS and TC while simultaneously accounting for outliers and the clustering of patients in 87 hospitals. Relative risks (RR) for hospital mortality were calculated using binomial regression. The NF hospitalization rate in Florida was 1.3/100,000. The median TC was US$54,533 and cumulative charges for all 216 patients were nearly US$20 million. Patients aged > or =44 years at the time of admission were five times as likely to expire in the hospital than patients who were aged < or =43 years (adjusted RR 5.08, P=0.03). Unexpectedly, diabetes was associated with a 61% reduction in the risk of hospital mortality (adjusted RR 0.39, P=0.04). Age > or =44 years was the most powerful predictor of prolonged LOS, elevated TC, and an increased risk of hospital mortality in patients suffering from NF.