Inappropriate initial antibiotic treatment for complicated skin and soft tissue infections in hospitalized patients: incidence and associated factors

The Etiology, Antibiotic Therapy and Outcomes of Bacteremic Skin and Soft-Tissue Infections in Onco-Hematological Patients

OBJECTIVES

to assess the current epidemiology, antibiotic therapy and outcomes of onco- hematological patients with bacteremic skin and soft-tissue infections (SSTIs), and to identify the risk factors for Gram-negative bacilli (GNB) infection and for early and overall mortality.

METHODS

episodes of bacteremic SSTIs occurring in cancer patients at two hospitals were prospectively recorded and retrospectively analyzed.

RESULTS

Of 164 episodes of bacteremic SSTIs, 53% occurred in patients with solid tumors and 47% with hematological malignancies. GNB represented 45.5% of all episodes, led by Pseudomonas aeruginosa (37.8%). Multidrug resistance rate was 16%. Inadequate empirical antibiotic therapy (IEAT) occurred in 17.7% of episodes, rising to 34.6% in those due to resistant bacteria. Independent risk factors for GNB infection were corticosteroid therapy and skin necrosis. Early and overall case-fatality rates were 12% and 21%, respectively. Risk factors for early mortality were older age, septic shock, and IEAT, and for overall mortality were older age, septic shock and resistant bacteria.

CONCLUSIONS

GNB bacteremic SSTI was common, particularly if corticosteroid therapy or skin necrosis. IEAT was frequent in resistant bacteria infections. Mortality occurred mainly in older patients with septic shock, resistant bacteria and IEAT. These results might guide empirical antibiotic therapy in this high-risk population.

Rapid diagnostics for skin and soft tissue infections: the current landscape and future potential

PURPOSE OF REVIEW

Managing antimicrobial therapy in patients with complicated skin and soft tissue infections (SSTI) constitutes a growing challenge due to the wide spectrum of potential pathogens and resistance phenotypes. Today, microbiological documentation relies on cultural methods. This review summarizes the available evidence regarding the clinical input of rapid microbiological diagnostic tools (RMDT) and their impact on the management of antimicrobial therapy in SSTI.

RECENT FINDINGS

Accurate tools are already available for the early detection of methicillin-resistant Staphylococcus aureus (MRSA) in SSTI samples and may help avoiding or shortening empirical anti-MRSA coverage. Further research is necessary to develop and evaluate RMDT detecting group A streptococci (e.g., antigenic test) and Gram-negative pathogens (e.g., multiplex PCR assays), including through point-of-care utilization. Next-generation sequencing (NGS) methods could provide pivotal information for the stewardship of antimicrobial therapy, especially in case of polymicrobial or fungal SSTI and in the immunocompromised host; however, a shortening in the turnaround time and prospective data regarding their therapeutic input are needed to better appraise the clinical positioning of these promising approaches.

SUMMARY

The clinical input of RMDT in SSTI is currently limited due to the scarcity of available dedicated assays and the polymicrobial feature of certain cases. NGS appears as a relevant tool but requires further developments before its implementation in routine clinical practice.

Cost analysis of dalbavancin versus standard of care for the treatment of acute bacterial skin and skin structure infections (ABSSSIs) in two Italian hospitals

Objectives

Thanks to its long half-life, dalbavancin qualifies as an optimal drug for saving costs. We aimed to assess the cost and effectiveness of dalbavancin versus the standard of care (SoC).

Patients and methods

We conducted a multicentre retrospective study, including all hospitalized or outpatients diagnosed with ABSSSIs at Padua University Hospital, Padua and San Paolo Hospital, Milan (1 January 2016 to 31 July 2020). We compared patients according to antibiotic treatment (dalbavancin versus SoC), the number of lines of dalbavancin treatment, and monotherapy or combination (dalbavancin in association with other antibiotics). Primary endpoints were direct medical costs and length of hospital stay (LOS) associated with ABSSSI management; Student's t-test, chi-squared test and one-way ANOVA were used.

Results

One hundred and twenty-six of 228 (55.3%) patients received SoC, while 102/228 (44.7%) received dalbavancin. Twenty-seven of the 102 (26.5%) patients received dalbavancin as first-line treatment, 46 (45.1%) as second-line, and 29 (28.4%) as third- or higher-line treatment. Most patients received dalbavancin as monotherapy (62/102; 60.8%). Compared with SoC, dalbavancin was associated with a significant reduction of LOS (5 ± 7.47 days for dalbavancin, 9.2 ± 5.59 days for SoC; P < 0.00001) and with lower mean direct medical costs (3470 ± 2768€ for dalbavancin; 3493 ± 1901€ for SoC; P = 0.9401). LOS was also reduced for first-line dalbavancin, in comparison with second-, third- or higher-line groups, and for dalbavancin monotherapy versus combination therapy. Mean direct medical costs were significantly lower in first-line dalbavancin compared with higher lines, but no cost difference was observed between monotherapy and combination therapy.

Conclusions

Monotherapy with first-line dalbavancin was confirmed as a promising strategy for ABSSSIs in real-life settings, thanks to its property in reducing LOS and saving direct medical costs.

Optimization of Antibiotic Selection in the Emergency Department for Adult Skin and Soft Tissue Infections

Objectives: Emergency department (ED) order sets that include skin and soft tissue infections (SSTI) stratification and antimicrobial selection criteria may improve clinical outcomes and appropriateness of initial antibiotic selection. The purpose of this study was to optimize and evaluate antimicrobial prescribing for SSTI in the ED by implementing an institution specific Infectious Diseases Society of America (IDSA) guideline directed computerized provider order entry (CPOE) order set. The primary outcome was the rate of appropriate antibiotic prescribing for SSTI in the ED before and after order set revision. Secondary outcomes were length of hospital stay, rate of continuity of antibiotics from the ED to hospital admission orders, and frequency of order set utilization. Methods: This was a single-centered, retrospective, cohort study. The ED SSTI order set revision reflected current IDSA guidelines, institution formulary, and institution antibiogram. Results: A total of 180 patients were included in the study. The rate of appropriate antibiotic prescribing was 74.4% and 78.9% (P = .60) in the pre-revision and post-revision groups, respectively. Length of hospital stay of admitted patients was 4.93 and 4.32 days (P = .61). Rate of antibiotics continued from the ED to admission was 62.1% and 59.4% (P = .99). Order set utilization was 17.8% and 24.4% (P = .36). A subgroup analysis found appropriateness increased with order set use in admitted patients (50% vs 88.2%; P = .0382) and total patients (50% vs 81.8%; P = .037). Conclusion: An order set reflective of current IDSA guidelines and institution specific antibiogram showed a similar rate of appropriate antibiotic selection compared to provider's clinical judgment. Provider awareness of SSTI management could have been a limitation to the study.

Glutathione-Conjugated Hydrogels: Flexible Vehicles for Personalized Treatment of Bacterial Infections

PURPOSE

Skin and soft tissue infections are increasingly prevalent and often complicated by potentially fatal therapeutic hurdles, such as poor drug perfusion and antibiotic resistance. Delivery vehicles capable of versatile loading may improve local bioavailability and minimize systemic toxicities yet such vehicles are not clinically available. Therefore, we aimed to expand upon the use of glutathione-conjugated poly(ethylene glycol) GSH-PEG hydrogels beyond protein delivery and evaluate the ability to deliver traditional therapeutic molecules.

METHODS

PEG and GSH-PEG hydrogels were prepared using ultraviolet light (UV)-polymerization. Hydrogel loading and release of selected drug candidates was examined using UV-visible spectrometry. Therapeutic molecules and GST-fusion protein loading was examined using UV-visible and fluorescent spectrometry. Efficacy of released meropenem was assessed against meropenem-sensitive and -resistant P. aeruginosa in an agar diffusion bioassay.

RESULTS

For all tested agents, GSH-PEG hydrogels demonstrated time-dependent loading whereas PEG hydrogels did not. GSH-PEG hydrogels released meropenem over 24 h. Co-loading of biologic and traditional therapeutics into a single vehicle was successfully demonstrated. Meropenem-loaded GSH-PEG hydrogels inhibited the growth of meropenem-sensitive and resistant P. aeruginosa isolates.

CONCLUSION

GSH ligands within GSH-PEG hydrogels allow loading and effective delivery of charged therapeutic agents, in addition to biologic therapeutics.

Amplify antimicrobial photo dynamic therapy efficacy with poly-beta-amino esters (PBAEs)

Light-activated antimicrobial agents (photosensitisers) are promising alternatives to antibiotics for the treatment of skin infections and wounds through antimicrobial photo dynamic therapy (aPDT); utilisation of this technique is still restricted by general low efficacy requiring long exposure time (in the order of tens of minutes) that make the treatment very resource intensive. We report for the first time the possibility of harvesting the cell penetrating properties of poly-beta-amino esters (PBAEs) in combination with toluidine blue O (TBO) to shorten aPDT exposure time. Candidates capable of inactivation rates 30 times quicker than pure TBO were discovered and further improvements through PBAE backbone optimisation could be foreseen. Efficacy of the complexes was PBAE-dependent on a combination of TBO uptake and a newly discovered and unexpected role of PBAEs on reactive species production. Chemometric approach of partial least square regression was employed to assess the critical PBAE properties involved in this newly observed phenomenon in order to elicit a possible mechanism. The superior antimicrobial performance of this new approach benefits from the use of well established, low-cost and safe dye (TBO) coupled with inexpensive, widely tested and biodegradable polymers also known to be safe. Moreover, no adverse cytotoxic effects of the PBAEs adjuvated TBO delivery have been observed on a skin cells in vitro model demonstrating the safety profile of this new technology.

Gram-Negative Skin and Soft Tissue Infections

Skin and soft tissue infections (SSTIs) frequently are encountered in clinical practice, and gram-negative bacilli (GNB) constitute an underrated portion of their etiology. The rate of GNB-causing SSTIs is increasing, especially with the rise in antimicrobial resistance. Although the diagnosis of SSTIs mostly is clinical, rapid diagnostic modalities can shorten the time to initiating proper therapy and improving outcomes. Novel antibiotics are active against GNB SSTIs and can be of great value in the management. This review provides an overview of the role of GNB in SSTIs and summarizes their epidemiology, risk factors, outcome, and clinical management.

Current Epidemiology, Etiology, and Burden of Acute Skin Infections in the United States

The US burden of acute skin infections is substantial. While Staphylococcus aureus and Streptococcus spp. are the most common causes, gram-negative bacteria and mixed infections can occur in some settings. These mixed infections are more likely to result in inappropriate empiric antibiotic therapy. Important challenges remain in diagnosing and treating acute skin infections.

A Comparison of the Efficacy and Safety of Intravenous Followed by Oral Delafloxacin With Vancomycin Plus Aztreonam for the Treatment of Acute Bacterial Skin and Skin Structure Infections: A Phase 3, Multinational, Double-Blind, Randomized Study

Background

Delafloxacin is an intravenous (IV)/oral anionic fluoroquinolone with activity against gram-positive (including methicillin-resistant Staphylococcus aureus [MRSA]), gram-negative, atypical, and anaerobic organisms. It is approved in the United States for acute bacterial skin and skin structure infections (ABSSSIs) caused by designated susceptible gram-positive and gram-negative organisms, and is in development for the treatment of community-acquired bacterial pneumonia.

Methods

A multicenter, randomized, double-blind trial of 850 adults with ABSSSI compared delafloxacin 300 mg IV every 12 hours for 3 days with a switch to 450 mg oral delafloxacin, to vancomycin 15 mg/kg IV with aztreonam for 5–14 days. The primary endpoint was objective response at 48–72 hours. Investigator-assessed response based on resolution of signs and symptoms at follow-up (day 14 ± 1), and late follow-up (day 21–28) were secondary endpoints.

Results

In the intent-to-treat analysis set, the objective response was 83.7% in the delafloxacin arm and 80.6% in the comparator arm. Investigator-assessed success was similar at follow-up (87.2% vs 84.4%) and late follow-up (83.5% vs 82.2%). Delafloxacin was comparable to vancomycin + aztreonam in eradication of MRSA at 96.0% vs 97.0% at follow-up. Frequency of treatment-emergent adverse events between the groups was similar. Treatment-emergent adverse events leading to study drug discontinuation was higher in the vancomycin + aztreonam group (1.2% vs 2.4%).

Conclusions

In ABSSSI patients, IV/oral delafloxacin monotherapy was noninferior to IV vancomycin + aztreonam combination therapy for both the objective response and the investigator-assessed response at follow-up and late follow-up. Delafloxacin was well tolerated as monotherapy in treatment of ABSSSIs.

Clinical Trials Registration

NCT01984684.

Analysis of Pooled Phase III Efficacy Data for Delafloxacin in Acute Bacterial Skin and Skin Structure Infections

BACKGROUND

Delafloxacin is an oral or intravenous (IV) antibiotic indicated for the treatment of acute bacterial skin and skin structure infections (ABSSSI), including both gram-positive (including methicillin-resistant Staphylococcus aureus [MRSA]) and gram-negative organisms. Chemically distinct from other quinolones, delafloxacin exhibits enhanced potency, particularly against gram-positive pathogens. The integration of efficacy data across the Phase III ABSSSI studies is presented here and allows for additional examination of results across subgroups.

METHODS

Results of 2 multicenter, randomized, double-blind trials of 1510 adults with ABSSSI were pooled for this analysis. Subjects in the vancomycin arm received 15 mg/kg, plus 1-2 g of aztreonam every 12 hours. Delafloxacin was dosed at 300 mg IV every 12 hours in Study 302; dosing in Study 303 was 300 mg IV every 12 hours for 3 days, with a mandatory, blinded switch to delafloxacin at 450 mg orally every 12 hours. The primary endpoint was objective response (OR), defined as a ≥20% reduction of lesion spread of erythema area at the primary infection site at 48 to 72 hours (±2 hours), in the absence of clinical failure. Investigator-assessed response, based on the resolution of signs and symptoms at follow-up (FU; Day 14 ± 1) and late follow-up (LFU; Day 21- 28), were secondary endpoints.

RESULTS

In the intent-to-treat analysis set, the OR was 81.3% in the delafloxacin arm and 80.7% in the comparator arm (mean treatment difference 0.8%, 95% confidence interval -3.2% to 4.7). Results for OR in the defined subgroups showed delafloxacin to be comparable to vancomycin/aztreonam. Investigator-assessed success was similar at FU (84.7% versus 84.1%) and LFU (82.0% versus 81.7%). Delafloxacin was comparable to vancomycin/aztreonam in the eradication of MRSA, at 98.1% versus 98.0%, respectively, at FU. The frequencies of treatment-emergent adverse events between the groups were similar.

CONCLUSIONS

Overall, IV/oral delafloxacin fixed-dose monotherapy was non-inferior to IV vancomycin/aztreonam combination therapy and was well tolerated in each Phase III study, as well as in the pooled analysis, regardless of endpoint or analysis population.

Factors associated with readmission and mortality in adult patients with skin and soft tissue infections

BACKGROUND

Skin and soft tissue infections (SSTIs) are a common cause of consultation, and complicated cases require hospitalization. We describe factors that are related to readmission and/or mortality of hospitalized patients diagnosed with SSTIs.

METHODS

Retrospective review of hospital-admitted patients with a diagnosis of cellulitis, abscess, hidradenitis, fasciitis, and Fournier's gangrene. Cases from January 2002 to October 2015 were extracted from the diagnostic codification database of the Archives and Clinical Documentation Department.

FINDINGS

We studied 1,482 episodes of hospitalized patients diagnosed with SSTIs. There were 187 (12.3%) readmissions, the most frequent diagnosis was cellulitis (72.7%), and the most commonly isolated microorganism was Staphylococcus aureus (25; 30.1%). Factors associated with readmissions were healthcare-related infections (P = 0.002), prior antibiotic therapy (P < 0.001), ischemic heart disease (P = 0.01), chronic liver disease (P = 0.001), and diabetes mellitus (DM) (P = 0.006). The number of patients who died as a result of an infection was 34 (2.2%) and, in these patients, the most common diagnosis was also cellulitis (79.4%), which in 52.9% (P = 0.001) was community acquired. DM (P = 0.01), heart failure (P = 0.001), and chronic liver disease (P = 0.003) were the most frequent comorbidities. This group presented more complications (P < 0.005) such as endocarditis (P < 0.005), amputation (P = 0.018), severe sepsis (P < 0.005), and septic shock (P < 0.001).

CONCLUSIONS

Readmitted patients had healthcare-related S. aureus infection, had received prior antibiotic therapy, and presented comorbid conditions such as ischemic heart disease, peripheral vascular disease, chronic liver disease, or DM. Comorbidities such as advanced age, DM, heart failure, and chronic liver disease were associated with complications and higher infection-related mortality.

Adherence to antibiotic guidelines for erysipelas or cellulitis is associated with a favorable outcome

Outside areas of S. aureus strains resistant to methicillin (MRSA) in the community, no studies showed a relationship between the treatment for erysipelas or cellulitis and the outcome. We aimed to measure the impact of an internal therapeutic protocol, based on national guidelines on patients' outcome. This study was based on the dashboard of the infectious diseases department, which prospectively includes 28 parameters for all admitted patients. We included community-acquired erysipelas and cellulitis; exclusion criteria were abscesses at admission; ear, nose, throat, or dental cellulitis; pyomyositis; and length of stay ≤ 2 days. Adherence to guidelines was defined by the use of amoxicillin, amoxicillin/clavulanic acid, clindamycin, or pristinamycin, alone or in combination or successively. A poor outcome was defined by surgical procedure or intensive care requirement or death occurring after 5 days or more of antibiotic therapy. From July 2005 to June 2017, 630 cases of erysipelas or cellulitis were included. Blood cultures performed in 567 patients (90%) were positive in 39 cases (6.9%). Adherence rate to guidelines was 65% (410 cases). A poor outcome was recorded in 54 (8.5%) patients, less frequently in case of adherence to guidelines: 26/410 (6.3%) vs 28/220 (12.7%), p = 0.007. In logistic regression analysis, two risk factors were associated with a poor outcome: peripheral arterial disease, AOR 4.80 (2.20-10.49); and bacteremia, AOR 5.21 (2.31-11.76), while guideline adherence was the only modifiable protective factor, OR 0.48 (0.26-0.89). In erysipelas and cellulitis, adherence to guidelines was associated with a favorable outcome.

Influence of multidrug resistant organisms on the outcome of diabetic foot infection

OBJECTIVES

We described the clinical outcomes of the diabetic patients who had foot infections with multidrug resistant organisms.

METHODS

We included the patients with diabetic foot infections (DFI) from 19 centers, between May 2011 and December 2015. Infection was defined according to IDSA DFI guidelines. Patients with severe infection, complicated moderate infection were hospitalized. The patients were followed-up for 6 months after discharge.

RESULTS

In total, 791 patients with DFI were included, 531(67%) were male, median age was 62 (19-90). Severe infection was diagnosed in 85 (11%) patients. Osteomyelitis was diagnosed in 291(36.8%) patients. 536 microorganisms were isolated, the most common microorganisms were S. aureus (20%), P. aeruginosa (19%) and E. coli (12%). Methicillin resistance (MR) rate among Staphylococcus aureus isolates was 31%. Multidrug resistant bacteria were detected in 21% of P. aeruginosa isolates. ESBL (+) Gram negative bacteria (GNB) was detected in 38% of E. coli and Klebsiella isolates. Sixty three patients (8%) were re-hospitalized. Of the 791 patiens, 127 (16%) had major amputation, and 24 (3%) patients died. In multivariate analysis, significant predictors for fatality were; dialysis (OR: 8.3, CI: 1.82-38.15, p=0.006), isolation of Klebsiella spp. (OR:7.7, CI: 1.24-47.96, p=0.028), and chronic heart failure (OR: 3, CI: 1.01-9.04, p=0.05). MR Staphylococcus was detected in 21% of the rehospitalized patients, as the most common microorganism (p<0.001).

CONCLUSION

Among rehospitalized patients, methicillin resistant Staphylococcus infections was detected as the most common agent, and Klebsiella spp. infections were found to be significantly associated with fatality.

What is new in the management of skin and soft tissue infections in 2016?

PURPOSE OF REVIEW

Skin and soft tissue infections (SSTIs) are the most frequent infectious cause of referrals to emergency departments and hospital admissions in developed world, contributing to significant morbidity and healthcare expenditures. We sought to review recent literature covering epidemiology and management of SSTIs.

RECENT FINDINGS

Incidence trends of SSTIs were increasing worldwide with Staphylococcus aureus and streptococci predominating and methicillin-resistant S. aureus (MRSA) posing additional challenges, because of high rates of treatment failure and relapse. Development of new antimicrobials was associated with an appraisal of regulatory definitions and endpoints. Prediction of clinical response can be very tricky, because of variable risk factors for recurrence or treatment failure, depending mostly on the host. Precise indications for new antimicrobials should be established; their integration into clinical practice algorithms may serve reduction of unnecessary admissions, overtreatment and total costs.

SUMMARY

New antimicrobials with activity against MRSA have been recently launched. Long-acting agents, mainly oritavancin and dalbavancin, provide the opportunity of single-dose treatment and early discharge. Further outpatient treatment options include new per os antibiotics such as oxazolidinones. Validated assessment tools are urgently needed to support decision-making toward rational resource utilization and delivery of optimal treatment.

Management of acute bacterial skin and skin structure infections with a focus on patients at high risk of treatment failure

Over the last 25 years, the terminology of skin and soft tissue infections, as well as their classification for optimal management of patients, has changed. The so-called and recently introduced term 'acute bacterial skin and skin structure infections' (ABSSSIs), a cluster of fairly common types of infection, including abscesses, cellulitis, and wound infections, require an immediate effective antibacterial treatment as part of a timely and cautious management. The extreme level of resistance globally to many antibiotic drugs in the prevalent causative pathogens, the presence of risk factors of treatment failure, and the high epidemic of comorbidities (e.g. diabetes and obesity) make the appropriate selection of the antibiotic for physicians highly challenging. The selection of antibiotics is primarily empirical for ABSSSI patients which subsequently can be adjusted based on culture results, although rarely available in outpatient management. There is substantial evidence suggesting that inappropriate antibiotic treatment is given to approximately 20-25% of patients, potentially prolonging their hospital stay and increasing the risk of morbidity and mortality. The current review paper discusses the concerns related to the management of ABSSSI and the patient types who are most vulnerable to poor outcomes. It also highlights the key management time-points that treating physicians and surgeons must be aware of in order to achieve clinical success and to discharge patients from the hospital as early as possible.

Current and future trends in antibiotic therapy of acute bacterial skin and skin-structure infections

In 2013 the US Food and Drug Administration (FDA) issued recommendations and guidance on developing drugs for treatment of skin infection using a new definition of acute bacterial skin and skin-structure infection (ABSSSI). The new classification includes cellulitis, erysipelas, major skin abscesses and wound infection with a considerable extension of skin involvement, clearly referring to a severe subset of skin infections. The main goal of the FDA was to better identify specific infections where the advantages of a new antibiotic could be precisely estimated through quantifiable parameters, such as improvement of the lesion size and of systemic signs of infection. Before the spread and diffusion of methicillin-resistant Staphylococcus aureus (MRSA) in skin infections, antibiotic therapy was relatively straightforward. Using an empiric approach, a β-lactam was the preferred therapy and cultures from patients were rarely obtained. With the emergence of MRSA in the community setting, initial ABSSSI management has been changed and readdressed. Dalbavancin, oritavancin and tedizolid are new drugs, approved or in development for ABSSSI treatment, that also proved to be efficient against MRSA. Dalbavancin and oritavancin have a long half-life and can be dosed less frequently. This in turn makes it possible to treat patients with ABSSSI in an outpatient setting, avoiding hospitalization or potentially allowing earlier discharge, without compromising efficacy. In conclusion, characteristics of long-acting antibiotics could represent an opportunity for the management of ABSSSI and could profoundly modify the management of these infections by reducing or in some cases eliminating both costs and risks of hospitalization.

Skin and soft-tissue infections: Factors associated with mortality and re-admissions

INTRODUCTION

Skin and soft-tissue infections (SSTIs) are common and are linked to a wide variety of clinical conditions. Few studies have analysed the factors associated with mortality and re-admissions in medical patients with SSTIs. Accordingly, this study sought to describe the clinical and microbiological characteristics of patients diagnosed with SSTIs, and identify mortality and re-admission related factors.

PATIENTS AND METHODS

A total of 308 patients were included in the study. Clinical, socio-demographic and microbiological characteristics were collected. Univariate and logistic regression multivariate analyses were performed in order to identify factors associated with mortality and re-admission.

RESULTS

The bacteria responsible were identified in 95 (30.8%) patients, with gram-positive bacteria being isolated in 67.4% and gram-negative in 55.8% of cases. Multi-resistant bacteria were frequent (39%), and the initial empirical treatment proved inadequate in 25.3% of all cases. In-hospital mortality was 14.9%; the related variables were heart failure (OR=5.96; 95%CI: 1.93-18.47), chronic renal disease (OR=6.04; 95%CI: 1.80-20.22), necrotic infection (OR=4.33; 95%CI: 1.26-14.95), and inadequate empirical treatment (OR=44.74; 95%CI: 5.40-370.73). Six-month mortality was 8%, with the main related factors being chronic renal disease (OR: 3.03; 95%CI: 1.06-8.66), and a Barthel Index score of under 20 (OR: 3.62; 95%CI: 1.17-11.21). Re-admission was necessary in 26.3% of cases, with the readmission-related variables being male gender (OR: 2.12; 95%CI: 1.14-3.94), peripheral vascular disease (OR: 3.05; 95%CI: 1.25-7.41), and an age-adjusted Charlson Comorbidity Index score of over 3 (OR: 3.27; 95%CI: 1.40-7.63).

CONCLUSIONS

Clinical variables such as heart failure, chronic renal disease, peripheral vascular disease, and necrotic infection could help identify high-risk patients. The main factor associated with higher mortality was inadequate initial empirical treatment. Physicians should consider gram-negative, and even extended-spectrum beta-lactamase-producing bacteria when assigning initial empirical treatment for SSTIs, especially in healthcare-associated cases.

Epidemiology and Outcomes of Complicated Skin and Soft Tissue Infections among Inpatients in Southern China from 2008 to 2013

Complicated skin and soft tissue infections (cSSTI) are some of the most commonly treated infections in hospitals, and place heavy economic burdens on patients and society. Here we report the findings from an analysis of cSSTI based on a retrospective study which was conducted within the Chinese inpatient population. We focused our research on the analysis of the patient population, antibiotic treatment, clinical outcome and economic burden. The study population comprised 527 selected patients hospitalized between 2008 and 2013. Among the hospitalizations with microbiological diagnoses, 61.41% (n = 113) were diagnosed as infected with Gram-positive bacteria, while 46.20% (n = 85) were infected with Gram-negative bacteria. The most commonly found Gram-positive bacteria was Staphylococcus aureus (40.76%, n = 75), and the most common Gram-negative bacteria was Escherichia coli (14.13%, n = 26). About 20% of the Staphylococcus aureus were methicillin-resistant. The resistance rate of isolated Staphylococcus aureus or Escherichia coli to penicillin was around 90%; in contrast, the resistance rate to vancomycin, linezolid or imipenem was low (<20%). A large percentage of patients were treated with cephalosporins and fluoroquinolones, while vancomycin and imipenem were also included to treat drug-resistant pathogens. Over half of the hospitalizations (58.43%, n = 336) experienced treatment modifications. The cost to patients with antibiotic modifications was relatively higher than to those without. In conclusion, our study offers an analysis of the disease characteristics, microbiological diagnoses, treatment patterns and clinical outcomes of cSSTI in four hospitals in Guangdong Province, and sheds lights on the current clinical management of cSSTI in China.

Challenges in diagnosing infection in the diabetic foot

Diagnosing the presence of infection in the foot of a patient with diabetes can sometimes be a difficult task. Because open wounds are always colonized with microorganisms, most agree that infection should be diagnosed by the presence of systemic or local signs of inflammation. Determining whether or not infection is present in bone can be especially difficult. Diagnosis begins with a history and physical examination in which both classic and 'secondary' findings suggesting invasion of microorganisms or a host response are sought. Serological tests may be helpful, especially measurement of the erythrocyte sedimentation rate in osteomyelitis, but all (including bone biomarkers and procalcitonin) are relatively non-specific. Cultures of properly obtained soft tissue and bone specimens can diagnose and define the causative pathogens in diabetic foot infections. Newer molecular microbial techniques, which may not only identify more organisms but also virulence factors and antibiotic resistance, look very promising. Imaging tests generally begin with plain X-rays; when these are inconclusive or when more detail of bone or soft tissue abnormalities is required, more advanced studies are needed. Among these, magnetic resonance imaging is generally superior to standard radionuclide studies, but newer hybrid imaging techniques (single-photon emission computed tomography/computed tomography, positron emission tomography/computed tomography and positron emission tomography/magnetic resonance imaging) look to be useful techniques, and new radiopharmaceuticals are on the horizon. In some cases, ultrasonography, photographic and thermographic methods may also be diagnostically useful. Improved methods developed and tested over the past decade have clearly increased our accuracy in diagnosing diabetic foot infections.