Risk Factors for Infection with Pseudomonas aeruginosa in Diabetic Foot Infections

The increasing prevalence of Enterobacteriaceae as pathogens of diabetic foot osteomyelitis: A multicentre European cohort over two decades

OBJECTIVES

To investigate the microbiological trends of community-acquired diabetic foot osteomyelitis (DFO) over the past two decades in specialized academic centres in Switzerland, Spain, and Turkey.

METHODS

A retrospective analysis of DFO cohorts (2000-2019) from five centres (Geneva, Zurich, Las Palmas, Barcelona, Istanbul) stratified into four periods (P1-P4) to assess microbiological changes.

RESULTS

Among 1379 DFO episodes (76% male, median age 67 years; 90% type 2 diabetes, median duration 17 years), gram-positive bacteria were identified in 82%, including Staphylococcus aureus (47%). Methicillin-resistant S. aureus (MRSA) was more prevalent in Barcelona (36%), Las Palmas (24%), and Geneva (29%) than in Zurich (7%). Over time, gram-positive bacteria remained stable or decreased, particularly in Las Palmas (83% to 65%, P = 0.03). The proportion of MRSA decreased in Geneva (39% to 16%) and Las Palmas (37% to 9%), but remained stable in Barcelona. Enterobacteriaceae prevalence increased, notably in Geneva (16% to 39%, P < 0.01) and Las Palmas (27% to 41%, P < 0.01). Among gram-negative pathogens quinolone resistance was 12.5%. Enterobacteriaceae-DFO was associated with ischemic necrosis (OR 1.65), Las Palmas cohort (OR 3.14), and 2016-2019 period (OR 2.68).

CONCLUSIONS

A significant increase in Enterobacteriaceae-related DFOs was observed from 2016 to 2019, particularly in Mediterranean Europe.

Preparation and Biological Activity of Lignin-Silver Hybrid Nanoparticles

Silver nanoparticles (AgNPs) are excellent antimicrobial agents and promising candidates for preventing or treating bacterial infections caused by antibiotic resistant strains. However, their increasing use in commercial products raises concerns about their environmental impact. In addition, traditional physicochemical approaches often involve harmful agents and excessive energy consumption, resulting in AgNPs with short-term colloidal stability and silver ion leaching. To address these issues, we designed stable hybrid lignin-silver nanoparticles (AgLigNPs) intended to effectively hit bacterial envelopes as a main antimicrobial target. The lignin nanoparticles (LigNPs), serving as a reducing and stabilizing agent for AgNPs, have a median size of 256 nm and a circularity of 0.985. These LigNPs were prepared using the dialysis solvent exchange method, producing spherical particles stable under alkaline conditions and featuring reducing groups oriented toward a wrinkled surface, facilitating AgNPs synthesis and attachment. Maximum accumulation of silver on the LigNP surface was observed at a mass reaction ratio mAg:mLig of 0.25, at pH 11. The AgLigNPs completely inhibited suspension growth and reduced biofilm development by 50% in three tested strains of Pseudomonas aeruginosa at a concentration of 80/9.5 (lignin/silver) mg L-1. Compared to unattached AgNPs, AgLigNPs required two to eight times lower silver concentrations to achieve complete inhibition. Additionally, our silver-containing nanosystems were effective against bacteria at safe concentrations in HEK-293 and HaCaT tissue cultures. Stability experiments revealed that the nanosystems tend to aggregate in media used for bacterial cell cultures but remain stable in media used for tissue cultures. In all tested media, the nanoparticles retained their integrity, and the presence of lignin facilitated the prevention of silver ions from leaching. Overall, our data demonstrate the suitability of AgLigNPs for further valorization in the biomedical sector.

Molecular characterization of Pseudomonas aeruginosa from diabetic foot infections in Tunisia

Background. Pseudomonas aeruginosa is an invasive organism that frequently causes severe tissue damage in diabetic foot ulcers.Gap statement. The characterisation of P. aeruginosa strains isolated from diabetic foot infections has not been carried out in Tunisia.Purpose. The aim was to determine the prevalence of P. aeruginosa isolated from patients with diabetic foot infections (DFIs) in Tunisia and to characterize their resistance, virulence and molecular typing.Methods. Patients with DFIs admitted to the diabetes department of the International Hospital Centre of Tunisia, from September 2019 to April 2021, were included in this prospective study. P. aeruginosa were obtained from the wound swabs, aspiration and soft tissue biopsies during routine clinical care and were confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antimicrobial susceptibility testing, serotyping, integron and OprD characterization, virulence, biofilm production, pigment quantification, elastase activity and molecular typing were analysed in all recovered P. aeruginosa isolates by phenotypic tests, specific PCRs, sequencing, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing.Results. Sixteen P. aeruginosa isolates (16.3 %) were recovered from 98 samples of 78 diabetic patients and were classified into 6 serotypes (O:11 the most frequent), 11 different PFGE patterns and 10 sequence types (three of them new ones). The high-risk clone ST235 was found in two isolates. The highest resistance percentages were observed to netilmicin (69 %) and cefepime (43.8 %). Four multidrug-resistant (MDR) isolates (25 %) were detected, three of them being carbapenem-resistant. The ST235-MDR strain harboured the In51 class 1 integron (intI1 +aadA6+orfD+qacED1-sul1). According to the detection of 14 genes involved in virulence or quorum sensing, 5 virulotypes were observed, including 5 exoU-positive, 9 exoS-positive and 2 exoU/exoS-positive strains. The lasR gene was truncated by ISPpu21 insertion sequence in one isolate, and a deletion of 64 bp in the rhlR gene was detected in the ST235-MDR strain. Low biofilm, pyoverdine and elastase production were detected in all P. aeruginosa; however, the lasR-truncated strain showed a chronic infection phenotype characterized by loss of serotype-specific antigenicity, high production of phenazines and high biofilm formation.Conclusions. Our study demonstrated for the first time the prevalence and the molecular characterization of P. aeruginosa strains from DFIs in Tunisia, showing a high genetic diversity, moderate antimicrobial resistance, but a high number of virulence-related traits, highlighting their pathological importance.

What’s old is new again: Insights into diabetic foot microbiome

Diabetes is a chronic disease that is considered one of the most stubborn global health problems that continues to defy the efforts of scientists and physicians. The prevalence of diabetes in the global population continues to grow to alarming levels year after year, causing an increase in the incidence of diabetes complications and health care costs all over the world. One major complication of diabetes is the high susceptibility to infections especially in the lower limbs due to the immunocompromised state of diabetic patients, which is considered a definitive factor in all cases. Diabetic foot infections continue to be one of the most common infections in diabetic patients that are associated with a high risk of serious complications such as bone infection, limb amputations, and life-threatening systemic infections. In this review, we discussed the circumstances associated with the high risk of infection in diabetic patients as well as some of the most commonly isolated pathogens from diabetic foot infections and the related virulence behavior. In addition, we shed light on the different treatment strategies that aim at eradicating the infection.

Diabetic foot ulcer-a systematic review on relevant microbial etiology and antibiotic resistance in Asian countries

BACKGROUND AND AIMS

Diabetic foot ulcer (DFU) is one of the most common but uncontrolled health issues of diabetic patients that needs more therapeutic considerations. This systematic review aims to study the current status of the etiological agents responsible for DFU, their frequency in some of the most occurring Asian countries, and their antibiotic resistance pattern based on available studies.

METHODS

Here, the literature survey was conducted on all the DFU studies with the records of etiological agents and conventional therapeutic treatment published until March 2021 using Medical Literature Analysis and Retrieval System Online (MEDLINE) and Web of Science Core Collection (WoSCC) database.

RESULTS

Overall, in our study, a total of 73 studies representing 12 Asian countries worldwide have been included. We found that the highest number of studies were reported from India (45%) followed by Pakistan (11%), China, Iran and others. 71% of recent studies reported DFU being attributed to poly-microbial infections while the dominant position was significantly secured by Gram- negative bacteria (77%, p = 0.34). Staphylococcus aureus was found to be the most prevalent isolate followed by Pseudomonas and then Escherichia coli (mean value - 22%, 17%, and 15% respectively). Antibiotic sensitivity pattern was determined based on availability in terms of median resistance (MR) and interquartile range (IQR) which showed the growing resistance developed by both Gram-positive and Gram-negative isolates. Gram positive pathogens were still reported as susceptible to vancomycin (MR 0%, IQR 0-22.8%), linezolid (MR 0%, IQR 0-15.53%) and imipenem (MR 11%, IQR 0-23.53%). Carbapenem genera, colistin, and amikacin were the most effective drugs against Gram-negative pathogens.

CONCLUSION

The findings of this study highly recommend searching for alternative and complementary therapeutic regimens instead of prescribing conventional drugs blindly without investigating the progression of the stages of the ulcer, which may help reduce the medical and economic burden of this disease.

Relative Abundance and Detection of Pseudomonas aeruginosa from Chronic Wound Infections Globally

Pseudomonas aeruginosa is a difficult-to-treat pathogen that is frequently involved with chronic wound infections. Here, we conducted a literature search of world-wide studies published between 2005 and 2022 that described the microbiological profiles of chronic wound infections. For each continent, a hierarchy of pathogens was created to define the organisms that were most frequently isolated in each region. Except for South America, P. aeruginosa was the second most common organism in each major continent, with Staphylococcus aureus being the most abundant pathogen overall. When individual countries were evaluated, P. aeruginosa was the most frequently isolated organism in several Southeast Asia nations including India and Malaysia. P. aeruginosa was less commonly isolated from diabetic foot infections in North America, Europe, and Africa in comparison to other types of chronic wound infections. Additionally, the Levine wound swab technique may be a quick and painless way to isolate P. aeruginosa from wound infections, but the isolation of P. aeruginosa does not seem to be an informative predictor of the patient's clinical course. A multivariate risk assessment that accounts for the regional frequency of P. aeruginosa isolation may be an appropriate way to guide empiric management of chronic wound infections.

Effectiveness of Epidermal Growth Factor Loaded Carboxymethylcellulose (EGF-CMC) Hydrogel in Biofilm Formation in Wounds of Diabetic Patients: A Randomized Clinical Trial

Diabetic patients frequently develop wounds, which can be colonized by bacteria, mainly Staphylococcus aureus and Pseudomonas aeruginosa, with the ability to form biofilms. This study aimed to evaluate the colonization and biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa in chronic wounds of diabetic patients treated with a bioactive dressing (EGF-CMC), which consisted of a 2% carboxymethylcellulose (CMC) hydrogel loaded with epidermal growth factor (EGF). This randomized clinical trial was conducted with 25 participants: 14 treated with EGF-CMC hydrogel and 11 treated with CMC hydrogel for 12 weeks. Participants with type 2 diabetes mellitus were selected. All had diabetic foot ulcers or chronic venous ulcers. Swab collections were performed on weeks 1, 6, and 12. The laboratory analyses included the identification of strains, microbial quantification, virulence gene investigation, and the evaluation of biofilm formation. In total, 13 S. aureus strains and 15 P. aeruginosa strains were isolated. There were no statistically significant differences regarding bacterial loads and virulence genes. However, EGF-CMC-hydrogel-treated wounds were colonized by strains with lower biofilm formation abilities. The probability of isolating biofilm-producing strains from CMC-hydrogel-treated wounds was 83% greater than the probability of isolating biofilm-producing strains from EGF-CMC-treated wounds.

Diabetic Foot Infections: Bacterial Isolates From the Centers and Hospitals of Latin American Countries

Diabetic foot infections (DFIs) are one of the most important reasons for lower limb amputations. An adequate approach to the management of DFI implies control of infection using strategies of tissue debridement and empirical antibiotic treatment based on local microbiology. The aim of this study was to determine the bacterial isolates profile and antibiotic susceptibility patterns in samples from DFI from Latin American centers, on the premise that microbiology of this region differs from that of other continents and influences antimicrobial election. Three hundred and eighty-two samples from soft tissue and bone were studied from 17 centers of 4 countries. Three hundred and seven (80.4%; 95% confidence interval = 75.9-84.2) were positive. Gram negatives (GN) were isolated in 43.8% of all samples, not only in severe but also in mild infections, 51% in bone samples, more frequently in presence of ischemia (47% vs 38%; P = .07) and in wounds with longer duration of the lesion (30-20 days; P < .01). Staphylococcus aureus was the most frequent single germ (19.9%). Gram positives were isolated more frequently in patients without ischemia (53% vs 40%; P = .01). Enterococcus faecalis was the most frequent germ in bone samples (16.8%). Ciprofloxacin and trimethoprim-sulfamethoxazole were the oral antimicrobials most effective against GN. Trimethoprim-sulfamethoxazole and rifampicin were the oral antimicrobials most effective against Staphylococcus. Because of GN high antibiotic resistance patterns, patients treated in an ambulatory setting have to be controlled early after starting empiric treatment to assess response to therapy and hospitalize for parenteral antibiotics if oral treatment fails.

Microbiota of diabetic foot infections in a University Hospital in Bogotá, Colombia

The presence of infection in diabetic foot ulcers (DFU) is one of the main causes of lower limb amputation in the world. The presence of polymicrobial infections is usually the standard for isolation in such lesions, with Gram Positive (GP) germs being the main organisms involved, as is described in the global literature. However, some studies indicate a greater number of isolates with Gram Negative (GN) germs, reported mainly in the literature of Middle Eastern countries and in the tropics.

Pseudomonal Diabetic Foot Infections: Vive la Différence?

Objective

To assess the outcomes of diabetic foot infections (DFIs) due to Pseudomonas aeruginosa.

Patients and Methods

From April 24, 2013 to July 31, 2016, we analyzed data from patients prospectively enrolled in our clinical pathway of DFIs, comparing those with infection due to Pseudomonas with those without infection due to Pseudomonas.

Results

Overall, we assessed 1018 cases of DFIs: 392 with osteomyelitis and 626 with only soft tissue infections. The prevalence of P aeruginosa in deep wound cultures was 10% (104/1018); of the 1018 cultures, 22 were monomicrobial, 82 were polymicrobial, and 46 were with osteomyelitis. Overall, the patients were treated with a median of 1 surgical debridement and a total of 20 days of antibiotic therapy. In a comparison of crude groups, the proportion of clinical failures was significantly higher with Pseudomonas than with other pathogens (36/104 [35%] vs 218/914 [24%], respectively; P=.02). A multivariate analysis showed that pseudomonal DFIs did not recur more often than nonpseudomonal DFIs (hazard ratio, 1.0; 95% confidence interval, 0.6-1.7). Among the 104 cases of pseudomonal DFIs, there was no association between failure of treatment and the total duration of antibiotic therapy, duration of intravenous therapy, duration of combined antibiotic therapy with more than 1 agent, or duration of oral (fluoroquinolone) therapy. Among 15 cases of pseudomonal recurrence, 2 (13%) developed resistance to the antibiotic agent used for the index episode.

Conclusion

For DFIs caused by P aeruginosa, other than choosing an antibiotic agent that is active against the organism, it does not appear necessary to treat with a different therapeutic regimen compared with the treatment of nonpseudomonal DFIs. There is no difference!

Emerging Diabetic Foot Ulcer Microbiome Analysis Using Cutting Edge Technologies

One of the most prevalent complications of diabetes mellitus are diabetic foot ulcers (DFU). Diabetic foot ulcers represent a complex condition placing individuals at-risk for major lower extremity amputations and are an independent predictor of patient mortality. DFU heal poorly when standard of care therapy is applied. In fact, wound healing occurs only approximately 30% within 12 weeks and only 45% regardless of time when standard of care is utilized. Similarly, diabetic foot infections occur in half of all DFU and conventional microbiologic cultures can take several days to process before a result is known. DFU represent a significant challenge in this regard because DFU often demonstrate polymicrobial growth, become resistant to preferred antibiotic therapy, and do not inform providers about long-term prognosis. In addition, conventional culture yields may be affected by the timing of antibiotic administration and collection of tissue for analysis. This may lead to suboptimal antibiotic administration or debilitating amputations. The microbiome of DFU is a new frontier to better understand the interactions between host organisms and pathogenic ones. Newer molecular techniques are readily available to assist in analyzing the constituency of the microbiome of DFU. These emerging techniques have already been used to study the microbiome of DFU and have clinical implications that may alter standard of care practice in the near future. Here emerging molecular techniques that can provide clinicians with rapid DFU-related-information and help prognosticate outcomes in this vulnerable patient population are presented.

The Profile of Microbiological Pathogens in Diabetic Foot Ulcers

Diabetic foot, a main complication of diabetes mellitus, renders the foot susceptible to infection, and may eventually lead to non-traumatic limb amputation due to the deterioration of diabetic foot ulcers (DFUs). Characterizing the pathogen spectrum and antibiotic susceptibility is critical for the effective treatment of DFUs. In the current study, the characteristics and antibiotic susceptibility of the pathogen spectrum were analyzed. Secretions from the DFUs of 102 patients were cultured, and dominant pathogens were identified by using test cards. Antibiotic susceptibility of dominant pathogens was assayed by the Kirby–Bauer assay. We found that the dominant pathogens varied with age, duration of diabetes, blood sugar control, and the initial cause of ulcers. Moreover, the dominant pathogens were susceptible to at least one antibiotic. However, the antibacterial efficacy of several commonly used antibiotics decreased from 2016 to 2019. Our study indicates that the identification of dominant pathogens and antibiotic susceptibility testing is essential for the treatment of DFUs with effective antibiotics, while the abuse of antibiotics should be strictly restrained to reduce the generation of antibiotic-resistant strains.

How good are clinicians in predicting the presence of Pseudomonas spp. in diabetic foot infections? A prospective clinical evaluation

Introduction

The most frequently prescribed empirical antibiotic agents for mild and moderate diabetic foot infections (DFIs) are amino-penicillins and second-generation cephalosporins that do not cover Pseudomonas spp. Many clinicians believe they can predict the involvement of Pseudomonas in a DFI by visual and/or olfactory clues, but no data support this assertion.

Methods

In this prospective observational study, we separately asked 13 experienced (median 11 years) healthcare workers whether they thought the Pseudomonas spp. would be implicated in the DFI. Their predictions were compared with the results of cultures of deep/intraoperative specimens and/or the clinical remission of DFI achieved with antibiotic agents that did not cover Pseudomonas.

Results

Among 221 DFI episodes in 88 individual patients, intraoperative tissue cultures grew Pseudomonas in 22 cases (10%, including six bone samples). The presence of Pseudomonas was correctly predicted with a sensitivity of 0.32, specificity of 0.84, positive predictive value of 0.18 and negative predictive value 0.92. Despite two feedbacks of the interim results and a 2-year period, the clinicians' predictive performance did not improve.

Conclusion

The combined visual and olfactory performance of experienced clinicians in predicting the presence of Pseudomonas in a DFI was moderate, with better specificity than sensitivity, and did not improve over time. Further investigations are needed to determine whether clinicians should use a negative prediction of the presence of Pseudomonas in a DFI, especially in settings with a high prevalence of pseudomonal DFIs.

Efficacy of sub-MIC level of meropenem and ciprofloxacin against extensive drug-resistant (XDR) Pseudomonas aeruginosa isolates of diabetic foot ulcer patients

The increasing emergence of extensive drug-resistant bacteria (XDR) among chronic diabetic foot ulcer patients (DFU) possess serious threat which leads to foot amputation. The ideal measurement estimations of the presently accessible medications are getting insufficient against extensive drug-resistant strains. For quite a long-time piperacillin monotherapy, Piperacillin-tazobactam, ceftazidime, Carbapenem class of anti-toxin, ceftalozane-Tazobactam, and so on, has been the suggested therapy towards persistent instances of diabetic foot ulcer but because of the resistance mechanism of the potent pathogens the potency and usage of the antibiotic concentration regime is under the radar. Based on this hypothesis two isolates namely VIT PC 7 &VIT PC 9 were found to be resistant to all five classes of antibiotics exhibiting extensive drug resistance (XDR). The whole-genome sequence of Pseudomonas aeruginosa VIT PC 7 and VIT PC 9 data showed the presence of various RND efflux related genes and antibiotic resistance genes. The broth microdilution assay showed minimum inhibitory concentration (MIC) for ciprofloxacin and meropenem, Synergistic test was performed through checkerboard analysis and sub-MIC concentration of ciprofloxacin/meropenem was deduced using ∑ FICI, Time kills analysis was done for varying time interval to check the maximum reduction in CFU/ml of the bacterial cells, sub-MIC level of meropenem and ciprofloxacin showed inhibitory activity at lower concentration respectively. In vitro time-kill analysis showed the decrease in the number of cells, suggesting that the synergistic antimicrobial combinations are effective in decreasing the MIC level, and combinational test involving sub-MIC level of antibiotics also showed maximum reduction in biofilm forming cells, portraying the effectiveness of both the drugs. Accordingly, an expansion in the antimicrobial spectrum can be accomplished by utilizing the ideal measurements of ciprofloxacin/meropenem in persistent condition like diabetic foot ulcer, sub-MIC level of ciprofloxacin/meropenem could be a promising choice for anticipation against the ongoing drug-resistant crisis.

Microbiological profile of diabetic foot ulcers in Kuwait

Introduction

Diabetic foot ulcers (DFU) and infection (DFI) are a major diabetes-related problem around the world due to the high prevalence of diabetes in the population. The aim of our study was to determine the microbiological profile of infected ulcers in patients attending Dasman Diabetes Institute (DDI) clinics in Kuwait and to analyze the distribution of microbial isolates according to wound grade, sex, age and diabetes control.

Methods

We collected and analyzed clinical data and samples from 513 diabetic patients with foot ulcers referred to our podiatry clinic at DDI from Jan 2011 till Dec 2017.

Results

We show a higher prevalence of DFU in men than in women, and a greater percentage of DFU occurred in men at an earlier age (p<0.05). Only about half of the DFU were clinically infected (49.3%) but 92% of DFU showed bacterial growth in the microbiological lab analysis. In addition, we isolated more monomicrobial (57.3%) than polymicrobial (34.8%) DFI and representing an average of 1.30 pathogens per patient. The presence of Gram-positive and Gram-negative strains was comparable between men and women regardless their age or glucose levels. Interestingly, more Gram-positive strains are present in ulcers without ischemia while more Gram-negative strains are present in ulcers with ischemia (p<0.05). While Staphylococcus aureus was common in infected ulcers without ischemia, Pseudomonas aeruginosa was predominant in ulcers with infection and ischemia, regardless of ulcer depth. Finally, a higher percentage of women has controlled HbA1c levels (19.41% versus 11.95% in men) and more women in this group displayed non-infected wounds (60.6% and 43.90% for women and men, respectively).

Conclusion

Our results provide an updated picture of the DFI patterns and antibiotics resistance in patients attending Dasman Diabetes Institute (DDI) clinics in Kuwait which might help in adopting the appropriate treatment of infected foot and improving clinical outcomes.

Diabetic Foot Infections: Local Prevalence of and Case-Control Study of Risk Factors for Methicillin-Resistant Staphylococcus aureus and Pseudomonas aeruginosa

We identified deep diabetic foot infections by culture and conducted a case–control study examining the risk factors for moderate to severe methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PsA) diabetic foot infections. Our MRSA prevalence was lower than literature values; PsA was higher. Gangrene may be predictive of Pseudomonas infection.

A Retrospective Analysis of Microbiologic Profile of Foot Infections in Patients With Diabetic End-Stage Renal Disease

Objective

Individuals with diabetes and end-stage renal disease (ESRD) are at increased risk of foot ulceration and lower extremity amputation. Although risk factors and microbiologic analysis of diabetic foot infections ( DFIs) have been extensively studied, there are limited data available for this characteristic group.

Methods

Clinical, demographic, laboratory, microbiological data, and foot examination information were collected retrospectively regarding 94 patients with ESRD who were referred for DFI between 2006 and 2016 to hyperbaric oxygen therapy.

Results

In 6 of 94 patients with ESRD (mean age 60 years; 65 males [69.1%], 29 women [30.8%]; 91 undergoing hemodialysis [96.8%], one peritoneal dialysis [1%], two [2%] recent renal transplants), the lesions were bilateral; therefore, the evaluations were made over 100 DFIs. The most common pathogens isolated in deep wound cultures were Staphylococcus aureus and Pseudomonas aeruginosa, respectively, contributing to 27 (21.2%) and 16 (12.5%) of all 127 isolates. When the distribution of the isolates according to different Wagner grades were analyzed, it was found that the proportion of Gramnegative isolates increased statistically significantly with the ascending Wagner grade (P = .004).

Conclusion

DFIs indicate a serious complication associated with a high risk of amputation, prolonged antibiotic treatment, increased hospital and procedure demands, and the cost of health care, on patients with ESRD. The familiarization of causative pathogens underlying DFIs can aid the clinicians in the choice of appropriate empirical antibiotic treatment. This study emphasizes the need for greater attention to risk factors and the microbiologic profile of DFIs in this characteristic group.

Evolutionary trends in bacteria isolated from moderate and severe diabetic foot infections in a Portuguese tertiary center

INTRODUCTION

Diabetic Foot infections (DFI) are a major cause of hospitalization in patients with diabetes. The microbiological study of diabetic ulcers is essential to adequate antibiotic therapy and to minimize the selection of resistant microorganisms. The aim of this study was to characterize and to compare the evolution of isolated microorganisms between the biennium 2010-2011 and 2016-2017, in hospitalized patients with DFI.

MATERIAL AND METHODS

Retrospective evaluation of the clinical and analytical data of patients who were admitted due to DFI in 2010-2011 (group 2010/11) and 2016-2017 (group 2016/17). Only the first hospitalization for each patient was included. An adequate descriptive and comparative statistical analysis was performed.

RESULTS

There were 274 admissions due to DFI, 151 in 2010/11 and 123 in 2016/17. There was an increase in admissions due to neuroischemic DFI (51.0% in 2010/11 to 61.8% in 2016/17, p = 0.048). Staphylococcus aureus (SA) was the most common isolate in 2010/11 (26.7%). In 2016/17 most cultures were mixed polymicrobial and isolation of Enterobacteriaceae and Pseudomonas aeruginosa increased from 2010/11 to 2016/17 (15.9% to 30.6%, p = 0.001, and 9.1% to 13.7%, p = 0.048, respectively).

CONCLUSION

There was an increase in the prevalence of neuroischemic DFU. The Enterobacteriaceae family replaced SA as the most prevalent pathogen in DFI, with an increase in the isolation of gram-negative microorganisms and mixed polymicrobial cultures. Chronic neuroischemic infected ulcers usually present distinct bacterial isolates; knowledge about the most common agents is warranted in order to better select empiric antibiotic therapy.

Management of bacterial skin and skin structure infections with polymicrobial etiology

INTRODUCTION

Skin and Soft Tissue Infections (SSTIs) are some of the most commonly occurring bacterial infections, with a wide range of possible etiological pathogens and a considerable variety of clinical presentations and severity; from mild to severe life-threatening infections. Several classifications have been proposed based on a specific variable, such as anatomical localization, skin extension, progression rate, clinical presentation, severity, and etiological agent. Areas covered: The last criteria allows the differentiation of SSTIs as monomicrobial and polymicrobial. Among them, especially those infections with a long lasting or chronic course can be sustained by multiple microbial etiology. Most polymicrobial SSTIs can be included in the following: diabetes foot infections (DFIs), pressure ulcers infection, burn infection, and infected chronic ulcers. Expert commentary: The medical management of these infections comprises the administration of wide a spectrum antibiotic, taking into consideration the frequent occurrence of multidrug resistant microorganisms as responsible agents. An appropriate deep tissue specimen for microbiological examination is a very important issue, especially for polymicrobial infections, sometimes permitting the distinction between real pathogens and contaminants avoiding more complex antibiotic treatments. This aspect must be strongly emphasized, as frequently superficial swabs remain the specimen of choice because they are easy to obtain.