Application of self-assembled antibacterial nanofiber loaded oriented artificial skin in infected diabetic-related wound regeneration

Diabetic patients develop wounds that exhibit delayed healing, prolonged inflammatory responses, and slower epithelialization kinetics compared to non-diabetic patients. Diabetic foot ulcers(DFUs) affect approximately 18.6 million people worldwide. The presence of a high glucose microenvironment in DFUs results in the significant accumulation of bacterial infection and advanced glycation end products (AGEs). To solve this, a self-assemble antibacterial nanofiber(ANF) loaded oriential artificial skin (ANF@OAS) was introduced in this research, which is consisted of L/D-phenylalanine derivatives coupled the natural antimicrobial peptides. The ANF@OAS can effectively reduce AGEs production and suppress multiple resistant bacteria. Additionally, the ANF@OAS can suppress infection and stimulate wound healing in infected diabetic mice.

Clinical and Microbiological Profile of Diabetic Foot Ulcers Infected With Staphylococcus aureus in a Regional General Hospital in Bahia, Brazil

It is necessary to know the resistance profile of Staphylococcus aureus to better control diabetic foot ulcer infections, to establish rational antibiotic therapy, and to avoid the development of resistant strains. This cross-sectional study evaluated the clinical parameters, virulence, and antimicrobial resistance profiles of S aureus in patients with diabetic foot disease admitted to a public hospital. S aureus strains were identified in patients with diabetes with amputation indication. Infected tissue samples were collected, microbes were isolated and identified. The microbial resistance profile was determined. Samples were also analyzed for biofilm formation and other virulence markers. The 34 individuals examined were mostly men, black, aged 60 years on average, and generally had a low income and education level. Most individuals had type 2 diabetes, and the mean time since diagnosis was 13.9 years. On an SF-36 (the Medical Outcomes Study 36-item short-form health survey) quality-of-life questionnaire, 75% of individuals obtained a score equal to 0 for physical impairment. S aureus specimens from 17 patients were isolated, corresponding to 50% of samples. Five isolates were classified as methicillin-resistant S aureus (MRSA). Molecular typing revealed that 20% of MRSA strains were SCCmec type V and 80% were type I. All isolates were sensitive to doxycycline; 61.5% were resistant to erythromycin, 38.5% to cefoxitin, 30.7% to clindamycin and ciprofloxacin, 23% to meropenem, 15.3% to gentamicin, 38.5% to oxacillin, and 7.7% (one strain) to vancomycin. Regarding biofilm production, 53% of samples were able to produce biofilms, and 84.6% had icaA and/or icaD genes. Additionally, the following enterotoxin genes were identified in the isolates: seb, sec, seg, and sei (5.9%, 5.9%, 11.8%, and 23.9%, respectively) and agr types 1 (5.9%) and 2 (11.8%). Genotypic evaluation made it possible to understand the pathogenicity of S aureus strains isolated from the diabetic foot; laboratory tests can assist in the monitoring of patients with systemic involvement.

The Global Prevalence of Methicillin-Resistant Staphylococcus Aureus in Patients with Diabetic Foot Ulcers: A Systematic Review and Meta-Analysis

Objective

Diabetic foot ulcer (DFU) frequently leads to infections, with infected DFUs being a common cause of amputation. Infection by methicillin-resistant Staphylococcus aureus (MRSA) notably increases the necessity for amputation and surgical debridement in affected individuals. Consequently, determining the prevalence and trends of MRSA in patients with DFU is of critical importance. This study aimed to assess the global prevalence and to identify trends in the occurrence of MRSA in tissue or wound swab samples from DFU patients.

Methods

We conducted a comprehensive literature search across PubMed, Embase, Scopus, and Ovid, spanning from the inception of these databases to July 2023, imposing no language restrictions. The inclusion criteria required that the studies report on 30 or more patients with DFU. Additionally, we categorized our analysis based on geographic region, publication date, and the economic status of the patient's domicile. Our primary endpoint was to ascertain the prevalence of MRSA in DFUs. This systematic review has been registered at (https://www.crd.york.ac.uk/prospero/), with the identifier CRD 42023444360.

Results

Our analysis encompassed 40 studies involving 12,924 patients across 20 countries. We found that the overall prevalence of MRSA in DFU was 17% (95% Confidence Interval [CI] 0.14-0.20). Regional prevalence varied significantly: in South America, it was 61% (95% CI 0.46-0.76), in North America 20% (95% CI 0.12-0.27), in Europe 19% (95% CI 0.14-0.25), in Africa 13% (95% CI 0.06-0.20), and in other subgroups 11% (95% CI 0.08-0.15). The prevalence of MRSA in DFUs also differed according to the economic status of the countries: 19% (95% CI 0.15-0.23) in high-income countries, 24% (95% CI 0.1-0.37) in upper-middle-income countries, 11% (95% CI 0.07-0.15) in lower-middle-income countries, and 20% (95% CI 0.13-0.27) in low-income countries. Notably, there has been a decline in MRSA prevalence, from 25% before 2010 to 9% thereafter.

Conclusion

This meta-analysis reveals a decreasing yet still significant global prevalence of MRSA in DFUs. This trend has important implications for antimicrobial resistance and underscores the need for developing targeted programs focusing on infection prevention and exploring alternative therapeutic strategies.

Distribution of multidrug-resistant bacterial infections in diabetic foot ulcers and risk factors for drug resistance: a retrospective analysis

Objective

To investigate the distribution, drug resistance and risk factors of multi-drug resistant bacterias (MDROs) in patients with Type 2 diabetic foot ulcers (DFU).

Method

The clinical data, foot secretions, pathogenic microorganisms and drug sensitivity tests of 147 patients with type 2 diabetes admitted to our department from January 2018 to December 2021 were analyzed. Patients were divided into two groups according to whether they had been infected with MDROs or not. Seventy-one cases were infected with MDROs as the case group, and the remaining 76 cases were the control group. Chi-square test and t-test were used to analyze the results of MDROs infection and DFU, and logistic multivariate regression was used to evaluate the risk factors of MDROs infection.

Results

A total of 71 strains were isolated from the MDROs-positive group, with the top three being Staphylococcus aureus (46.48%), Escherichia coli (22.53%), and Pseudomonas aeruginosa (18.31%), respectively. Logistic multifactorial regression analysis showed that history of previous antimicrobial exposure, neuroischemic wound, Wagner grade 3-5, and combined osteomyelitis were associated with Type 2 diabetic foot infection MDROs (P < 0.05).

Conclusion

Previous history of antimicrobial exposure, neuroischemic wounds, Wagner grade 3-5, and combined osteomyelitis are independent risk factors for MDROs, which can identify the risk factors for MDROs at an early stage and help to identify people at high risk of MDROs infection and take relevant comprehensive treatment in time to slow down the development of the disease.

Community-associated methicillin-resistant Staphylococcus aureus infection of diabetic foot ulcers in an eastern diabetic foot center in a tertiary hospital in China: a retrospective study

BACKGROUND

Diabetic foot concerns are a major public health problem. Methicillin-resistant Staphylococcus aureus (MRSA) plays a significant role in diabetic foot ulcers. Community-associated MRSA has become notorious for skin and skin soft tissue infections over the last two decades. This study investigated MRSA infection in diabetic foot patients at a tertiary hospital, focusing on the epidemiology and characteristics of community-associated MRSA.

METHODS

A total of 149 patients with diabetic foot infection whose culture results indicated Staphylococcus aureus as the source were selected. Epidemiological investigations, clinical characteristics, laboratory index records, antibiotic susceptibility analysis, and clinical outcome tracking were performed in all cases. Based on oxacillin resistance using the Vitek Compact 2 system, cases were divided into methicillin-sensitive Staphylococcus aureus and MRSA groups. Subgroup analysis of the MRSA group was performed in accordance with the Centers for Disease Control definition: community-associated MRSA and hospital-associated MRSA.

RESULTS

The MRSA group (n = 41, 27.5%) had a longer duration of ulcers and hospital stay and higher hospitalization costs than the methicillin-sensitive Staphylococcus aureus group (n = 108, 72.5%). According to the classification criteria of Infectious Diseases Society of America, the severity of infection in the community-associated MRSA group was higher than that in the hospital-associated MRSA group. The analysis of antimicrobial susceptibility of 41 MRSA isolates showed that the resistance rates to erythromycin, clindamycin, quinolone, gentamicin, tetracycline, and rifampicin were 78.0%, 68.3%, 31.7%, 17.1%, 9.8%, and 2.4%, respectively. All the MRSA strains were sensitive to linezolid, tigecycline, and vancomycin. The resistance rates to quinolones and gentamycin in the community-associated MRSA group (both 0%) were lower than those in the hospital-associated MRSA group.

CONCLUSION

Emergence of MRSA in diabetic foot ulcer was associated with a prolonged wound duration and increased consumption of medical resources. Community-associated MRSA strains predominated among MRSA isolates from diabetic foot wounds and caused more severe infections.

Analysis of the Influence of Diabetic Nephropathy in Patients with Diabetic Foot Osteomyelitis

This study analyzed the influence of diabetic nephropathy on the healing prognosis after conservative surgery in diabetic foot osteomyelitis (DFO). A retrospective observational study was carried out between January 2021 and December 2022 and involved 278 outpatients with a diagnosis of DFO at a specialized diabetic foot unit, including 74 (26.62%) patients with DN (group 2) and 204 (73.38%) patients without DN (group 1). There were 266 (95.70%) ulcers on the forefoot, 8 (2.90%) on the midfoot, and 4 (1.45%) on the hindfoot (p = 0.992). The healing rates were 85.1% (n = 63) for group 2 and 81.3% (n = 165) for group 1 (p = 0.457). When exploring the influence of DN on the risk of delayed ulcer healing, the results did not show a significant effect [12 (6; 28) weeks among patients with DN vs. 12 (6; 21) weeks among patients without DN; p = 0.576]. No significant differences were observed in complications, with one (2.59%) death occurring in group 1 (p = 0.296) and three minor amputations being performed in both groups [two (5.13%) amputations in group 1 vs. one amputation (9.09%) in group 2; p = 0.217]. Bone cultures were performed for a total of 190 patients (133 in group 1 and 57 in group 2). Of these, 176 positive bone cultures were isolated: 71 positive bone cultures (57.7%) were monomicrobial cultures in group 1, with 30 (56.6%) in group 2. There were 52 (42.3%) that had at least two microorganisms in group 1, and 23 (43.4%) in group 2 (p = 0.890). The most frequently prescribed oral antibiotic was amoxicillin/clavulanate (43.89%), followed by levofloxacin (28.4%), and trimethoprim/sulfamethoxazole (14.7%). This study shows that DN does not have a significant influence on the healing prognosis of patients with DFO after conservative surgery.

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.

Infected Diabetic Wound Regeneration Using Peptide-Modified Chiral Dressing to Target Revascularization

Revascularization plays a critical role in the healing of diabetic wounds. Accumulation of advanced glycation end products (AGEs) and refractory multidrug resistant bacterial infection are the two major barriers to revascularization, directly leading to impaired healing of diabetic wounds. Here, an artfully designed chiral gel dressing is fabricated (named as HA-LM2-RMR), which consists of l-phenylalanine and cationic hexapeptide coassembled helical nanofibers cross-linked with hyaluronic acid via hydrogen bonding. This chiral gel possesses abundant chiral and cationic sites, not only effectively reducing AGEs via stereoselective interaction but also specifically killing multidrug resistant bacteria rather than host cells since cationic hexapeptides selectively interact with negatively charged microbial membrane. Surprisingly, the HA-LM2-RMR fibers present an attractive ability to activate sprouted angiogenesis of Human Umbilical Vein Endothelial Cells by upregulating VEGF and OPA1 expression. In comparison with clinical Prontosan Wound Gel, the HA-LM2-RMR gel presents superior healing efficiency in the infected diabetic wound with respect to angiogenesis and re-epithelialization, shortening the healing period from 21 days to 14 days. These findings for chiral wound dressing provide insights for the design and construction of diabetic wound dressings that target revascularization, which holds great potential to be utilized in tissue regenerative medicine.

Distribution of microbes and antimicrobial susceptibility in patients with diabetic foot infections in South China

BACKGROUND

To investigate the distribution of microbes and drug susceptibility in patients with diabetic foot infections (DFI) and provide guidance for clinical empirical treatment and the rational selection of antibacterial drugs.

METHODS

Retrospective analysis of the pathogenic bacterium distribution and antimicrobial susceptibility isolated from 581 DFI patients with different Wagner grades.

RESULTS

The 534 positive samples included 473 cases (88.58%)) of monomicrobial infections and 61 cases (11.42%) of polymicrobial infections before antibiotic therapy. A total of 656 strains were cultivated, including 387 (58.99%) strains of gram-positive organisms (GPOs), 235 (35.82%) gram-negative bacilli (GNB), and 21 (3.20%) fungal strains. Polymicrobial infections mainly occurred in patients with Wagner grade 3-4 ulcers. GPOs were predominant in Wagner grades 1-3 (grade 1: 96.67%, grade 2: 76.52%, grade 3 62.81%), and the most common was Staphylococcus aureus (grade 1: 31.66%, grade 2: 33.04%, grade 3 35.53%). GNB were predominant in grades 4-5 (grade 4: 51.46%, grade 5:60%), and the most common GNB in Wagner grades 4-5 was Proteus (grade 4:27.88%, grade 5: 42.86%), while the most common GPO was Enterococcus (grade 4:34.48%, grade 5:25.00%). Staphylococcus (including MRSA) and Enterococcus were still highly sensitive to vancomycin, linezolid, and tigecycline. Most GNB were still highly sensitive to meropenem, tigecycline, ertapenem, and amikacin. Proteus was most sensitive to amikacin (97.14%), followed by meropenem (92%) and ertapenem (80%).

CONCLUSION

The distribution of microbes and antimicrobial susceptibility in DFI patients varied with different Wagner grades. The most appropriate antimicrobial therapy should be selected based on the pathogen culture and antimicrobial susceptibility.

Comparative Clinical Outcomes of Patients with Diabetic Foot Infection Caused by Methicillin-Resistant Staphylococcus Aureus (MRSA) or Methicillin-Sensitive Staphylococcus Aureus (MSSA)

Few studies have addressed the interaction of specific pathogens with clinical outcomes in patients with diabetic foot infection (DFI). Our study aim was to compare the clinical outcomes among patients with DFI caused by methicillin-resistant Staphylococcus aureus (MRSA) with cases caused by methicillin-sensitive Staphylococcus aureus (MSSA). We gathered the data of 75 consecutive patients admitted at specialized outpatients diabetic with mild or moderate DFI in which S. aureus was isolated from bone or soft tissue specimens in pure or as a part of the polymicrobial culture. Patients were divided into two groups: those with MRSA infection and those with MSSA infection. Patients with MRSA diabetic foot infections were significantly associated with male gender (86% vs. 64%, P = .029), higher SINBAD Classification Score (3.6 ± 0.99 points vs. 2.8 ± 1.06 points, P = .001), longer mean wound evolution [17.8 (3;29.5) weeks versus 9.1 (1;12) weeks, P = .008], bone involvement [18 (50%) versus 9 (23.1%), P = .015] and longer mean healing time [18.2(8;28) weeks versus 9.1 (1;12) weeks, P = .008]. In addition, male gender (OR 8.81, 95% CI 2.00-38.84) and SINBAD Classification Score (OR 2.70, 1.46-5.00) were identified as independent risk factors for MRSA DFI. Significant differences in the number of surgical procedures to resolve infection [15 (41.7%) versus 13 (33.3%), P = .456] or in the mean healing time after surgical treatment [10.5 weeks (6.7;16.5) versus 6.1 weeks (3;8.7), P = .068] were not observed among groups, suggesting that when treatment is based on early and surgical debridement, MRSA infections are not associated with worse prognosis. In conclusion MRSA DFI has importance in clinical outcomes such as time to healing. We propose that recent lines of research regarding the genetic virulence of strains of S. aureus could provide new insights into our results.

Clinical and microbiological profile of bacterial pathogens from patients with diabetic foot infections at a teaching hospital in the northeast China

Background: Diabetic foot ulcer infection (DFI) is a frequent complication of diabetes.

Objective: The aim is to determine the clinical and microbiological profiles and the antibiotic resistance phenotype, analyze the DFIs risk factors.

Methods: The present study is a retrospective, single-center study conducted at a teaching hospital in the northeast China. 242 cases of patients with diabetic foot disease Wagner grade 0–5 over 2 years were screened and the recovered data consisted of the clinical features, risk factors, etiology and drug resistant profiles.

Results: The total percentage of Gram-negative rods (GNRs) and Gram-positive cocci (GPCs) was 138 (54.92%) and 113 (45.02%). The most common isolates were Pseudomonas aeruginosa and Staphylococcus aureus, accounting for 22.37% and 19.74%, respectively. Logistic regression analysis showed that the duration of ulcer, duration of antibiotic use, Wagner classification and osteomyelitis were risk factors for multi-drug resistant (MDR) bacteria infection ( p<0.05).

Conclusion: The predominate pathogens of patients with DFI were GNRs, followed by GPCs in the region. They exhibited the different antibiotic resistance phenotype. The data provided advice on selection of highly sensitive antibiotics in the management of DFIs.

Assessment of the Risk Factors of Multidrug-Resistant Organism Infection in Adults With Type 1 or Type 2 Diabetes and Diabetic Foot Ulcer

OBJECTIVES

To our knowledge, this is the first review to analyze the literature identifying risk factors for multidrug-resistant organism (MDRO) infection in patients with diabetic foot ulcer. The purpose of this study was to collect the currently published data to determine the most commonly and consistently identified risk factors for MDRO infection.

METHODS

PubMed, MEDLINE, BIOSIS, Web of Science and the Cochrane Library electronic databases were searched. The last search updated was in September 2019. The evaluated outcomes included age, male sex, type of diabetes, diabetes duration, level of glycated hemoglobin, ulcer type, wound duration, ulcer size, ulcer grade, osteomyelitis, previous antibiotic therapy and previous hospitalization. The standard mean difference or the odds ratio (OR) was calculated for continuous or dichotomous data, respectively. The quality of the studies was assessed, and meta-analyses were performed with Cochrane Collaboration's RevMan 5.0 software.

RESULTS

A total of 11 studies, including 1,229 patients provided evidence for 6 possible risk factors for MDRO infection. Ischemic ulcer (OR, 0.50; 95% confidence interval [CI], 0.35 to 0.71), ulcer size (standard mean difference, -0.27; 95% CI, -0.46 to -0.08), ulcer grade (OR, 0.36; 95% CI, 0.15 to 0.83), osteomyelitis (OR, 0.33; 95% CI, 0.25 to 0.45), previous antibiotic therapy (OR, 0.08; 95% CI, 0.04 to 0.14) and previous hospitalization (OR, 0.15; 95% CI, 0.08 to 0.28) were identified as risk factors for MDRO infection in patients with diabetic foot ulcer.

CONCLUSIONS

Our meta-analysis indicated that ischemic ulcer, ulcer size, ulcer grade, osteomyelitis, previous antibiotic therapy and previous hospitalization were associated with MDRO infection in patients with diabetic foot ulcer.

Molecular Characteristics of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolated from Diabetic Foot Infection

Background & Objective:

Diabetic foot ulcer (DFU), is one of the most frequent causes for hospitalizations in patients with diabetes. A major problem in the treatment of DFU is the increased-incidence of methicillin-resistant Staphylococcus aureus (MRSA). The aim of this study was to determine the SCCmec types of MRSA isolates and their epidemiology among patients with diabetes.

Methods:

This study was carried out on 145 diabetic patients with DFUs. The antibiotic susceptibility tests (ASTs) were performed using the disk diffusion method and E-test technique. SCCmec typing was done by multiplex PCR. Moreover, the presence of virulence toxin genes, including pvl and lukED was detected by PCR assay.

Results:

In 145 samples from which S. aureus was predominantly isolated, 19.48% were MRSA. Analysis of MRSA isolates revealed that the most prevalent SCCmec type was type IV (46.7%) followed by type III (30.0%) and type V (20.0%). One strain (3.3%) was untypeable. The prevalence of pvl and lukED was 56.7% and 100%, respectively.

Conclusion:

The high prevalence of MRSA in DFUs represents the high levels of antibiotic usage among patients with diabetes. In this study, resistance to other important clinical antibiotics was detected among MRSA isolates. The high proportion of SCCmec type IV and V strains, even in former hospitalized patients, indicates the entrance of these clones to the clinical setting.

Diabetic Foot Infection: Causative Pathogens and Empiric Antibiotherapy Considerations—The Experience of a Tertiary Center

Most moderate-to-severe diabetic foot infections (DFIs) require hospitalization with urgent surgical approach and administration of empiric antibiotherapy. To ensure optimal antibiotic coverage, regular microbiological background updates are imperative. The purpose is to characterize the microbiological profile and the antibiotic sensitivity pattern of the DFI causative pathogens isolated within a specialized DFI unit of a tertiary hospital, in order to establish evidence-based policies regarding empirical antibiotic use. A cross-sectional study was conducted. Microbiological cultures and corresponding antibiotic sensitivity tests collected from moderate-to-severe DFIs as a first approach to the hospitalized patient were retrieved and analyzed during a 12-month period. Two groups were analyzed: inpatients that had been previously followed at the diabetic foot clinic of the hospital and inpatients without a previous contact with the hospital services. A total of 125 isolates obtained from 87 patients were deemed for analysis. Globally, a predominance of Gram-positive bacteria was observed (60%). Staphylococcus aureus was the most common pathogen. The global ratio of methicillin-sensitive S aureus to methicillin-resistant S aureus (MRSA) was 1.3:1, with similar findings in both groups. According to the antibiotic sensitivity test results, and within the recommended empiric antibiotic regimens for DFI, piperacillin/tazobactam seems to be the most suitable option. Gram-positive bacteria prevail as the main isolates in DFIs. Screening for MRSA-specific risk factors is mandatory. When going for a first empiric therapy, piperacillin/tazobactam is recommended in this institution, and an anti-MRSA agent should be added early, if necessary. We encourage continuous monitoring for the bacterial prevalence in Portuguese diabetic foot centers as it is paramount for the decision making regarding DFI protocols.

Distribution of Microbes and Drug Susceptibility in Patients with Diabetic Foot Infections in Southwest China

OBJECTIVE

To investigate the microbial distribution and drug susceptibility among diabetic foot ulcers (DFUs) with different Wagner grades and between acute and chronic DFUs. Methods. We enrolled 428 DFU patients who were hospitalized and treated in the Southwest Hospital. We collected deep ulcer secretion for microbial culture and drug susceptibility tests and analyzed the results. We reexamined 67 patients with poor anti-infection efficacy and analyzed microbial species. Results: The 354 positive samples included 201 cases (56.8%) of single-pathogen infections and 153 cases (43.2%) of multiple-pathogen infections before antibiotic therapy. A total of 555 strains were cultivated, including 205 (36.9%) strains of gram-positive organisms (GPOs), 283 (51.0%) gram-negative bacilli (GNB), and 67 (12.1%) fungal strains. In terms of distribution, patients with different Wagner grades had different bacterial composition ratios (P < 0.01). Patients with Wagner grades 3-5 mainly had GNB. The specimens from chronic ulcer wounds were primarily GNB (54.2%), whereas fungi accounted for 14.4% of the infections; the distribution was significantly different from that of acute ulcers (P < 0.01). The susceptibility tests showed that the Staphylococcus genus was more susceptible to vancomycin, linezolid, and tigecycline. Tobramycin was the most effective drug (97%) for the treatment of Escherichia coli, followed by ertapenem (96.4%), imipenem (93.5%), and cefotetan (90%). Most of the remaining GNB were susceptible to antibiotics such as carbapenems, aminoglycosides, fluoroquinolones, ceftazidime, cefepime, and piperacillin-tazobactam (>63.2%). After antibiotic therapy, the positive rate of microbial culture was 52.2%, and the proportion of GNB and fungi increased to 68.9% and 20%.

CONCLUSION

The distribution and types of bacteria in diabetic foot infection (DFI) patients varied with the different Wagner classification grades, courses of the ulcers, and antibiotic therapy. Multidrug resistance were increased, and the clinical treatment of DFIs should select the most suitable antibiotics based on the pathogen culture and drug susceptibility test results.

The Relationship Between Osteomyelitis Complication and Drug-Resistant Infection Risk in Diabetic Foot Ulcer: A Meta-analysis

In this study, we aimed to investigate the relationship between osteomyelitis complications and drug-resistant infection risk in diabetic foot ulcer. Searches of MEDLINE and ISI databases were performed for the studies. Odds ratios (ORs) for drug-resistant infection incidence were calculated for diabetic foot ulcer patients with or without osteomyelitis complications. Eleven studies (12 cohorts) with 1526 patients were included in this study. Meta-analysis showed that the summary OR was 3.343 (95% CI = 2.355-4.745; Z = 6.75, P < .00001) when compared with osteomyelitis group and without osteomyelitis group. Significant publication bias was found. Sensitivity analysis by only pooled the adjusted ORs showed that the result was robust (the summary OR = 4.081, 95% CI = 2.471-6.739). Subgroup analysis by drug-resistant type showed that the summary OR was 4.391 (95% CI = 2.287-8.394) for methicillin-resistant infection subgroup, and 2.693 (95% CI = 1.882-3.851) for multidrug-resistant infection subgroup. The meta-regression showed that drug-resistant incidence ( t = -0.90, P = .389) and published year ( t = -0.11, P = .913) were not related with the OR changes. In conclusion, our meta-analysis indicates that osteomyelitis complications are related with drug-resistant infection risk in diabetic foot ulcer. We suggest bone culture-based narrow-spectrum antibiotic therapy for osteomyelitis for prevention drug-resistant infection in diabetic foot ulcer.

Empirical Antibiotic Treatment in Diabetic Foot Infection: A Study Focusing on the Culture and Antibiotic Sensitivity in a Population From Southern China

Diabetic foot and subsequent diabetic ulcer infections are the most devastating complication of diabetes. This study was conducted to explore the bacterial spectrum, sensitivity of microbials, and analysis of the empirical antibiotic regimens in our health center. The study included patients with diabetic foot ulcer infection (DFI) seen from 2009 to 2014. The patients included had all information covering the physical examination, laboratory tests, and image examinations. We sent appropriately obtained specimens for culture prior to starting empirical antibiotic therapy in all participants. A total of 312 patients were included: 52, 112, 95 and 53 patients within uninfected, mild, moderate, and severe infection groups. The total percentages of Gram-positive cocci (GPCs) and Gram-negative rods (GNRs) were 54% and 48.8% ( P = 0.63). The most common GPC was Staphylococcus aureus (22.4%) and GNR was Pseudomonas aeruginosa (11.9%). Methicillin-resistant Staphylococcus aureus was isolated from 21 patients (6.7%). Even in the mild infection group, there was no significant difference between GPC and GNR infection, irrespective of recent antibiotic use ( P = 0.053). The most frequently used empirical antibiotics in our center were second-/third-generation cephalosporin ± clindamycin, both in the mild and moderate/severe infection groups. In our center, the amoxicillin/clavulanate or ampicillin/sulbactam (β-L-ase 1) and second-/third-generation cephalosporins were highly resistant to the common GNR (30%-60%). The ticarcillin/clavulanate, piperacillin/tazuobactam (β-L-ase 2), fluoroquinolone, and group 2 carbapenem had good sensitivity. This study presents a comprehensive microbiological survey of diabetic foot ulcers in inpatients and provides reliable evidence of the local microbial epidemiology and sensitivity of antibiotics, which may help us improve clinical outcomes in DFI patients.

Blue Laser Inhibits Bacterial Growth of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa

OBJECTIVE

The purpose of this study was to analyze the influence of blue laser on bacterial growth of the main species that usually colonize cutaneous ulcers, as well as its effect over time following irradiation.

BACKGROUND DATA

The use of blue laser has been described as an adjuvant therapeutic method to inhibit bacterial growth, but there is no consensus about the best parameters to be used.

METHODS

Strains of Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, and Escherichia coli ATCC 25922 were suspended in saline solution at a concentration of 1.5×10(3) colony forming units (CFU)/mL. Next, 300 μL of this suspension was transferred to a microtitulation plate and exposed to a single blue laser irradiation (450 nm) at fluences of 0 (control), 3, 6, 12, 18, and 24 J/cm(2). Each suspension was spread over the surface of a Petri plate before being incubated at 37°C, and counts of CFU were determined after 24 and 48 h.

RESULTS

Blue laser inhibited the growth of S. aureus and P. aeruginosa at fluences >6 J/cm(2). On the other hand, E. coli was inhibited at all fluences tested, except at 24 J/cm(2).

CONCLUSIONS

Blue laser light was capable of inhibiting bacterial growth at low fluences over time, thus presenting no time-dependent effect.

Staphylococcus aureus Toxins and Diabetic Foot Ulcers: Role in Pathogenesis and Interest in Diagnosis

Infection of foot ulcers is a common, often severe and costly complication in diabetes. Diabetic foot infections (DFI) are mainly polymicrobial, and Staphylococcus aureus is the most frequent pathogen isolated. The numerous virulence factors and toxins produced by S. aureus during an infection are well characterized. However, some particular features could be observed in DFI. The aim of this review is to describe the role of S. aureus in DFI and the implication of its toxins in the establishment of the infection. Studies on this issue have helped to distinguish two S. aureus populations in DFI: toxinogenic S. aureus strains (harboring exfoliatin-, EDIN-, PVL- or TSST-encoding genes) and non-toxinogenic strains. Toxinogenic strains are often present in infections with a more severe grade and systemic impact, whereas non-toxinogenic strains seem to remain localized in deep structures and bone involving diabetic foot osteomyelitis. Testing the virulence profile of bacteria seems to be a promising way to predict the behavior of S. aureus in the chronic wounds.

Can We Stop Antibiotic Therapy When Signs and Symptoms Have Resolved in Diabetic Foot Infection Patients?

The study aimed to investigate whether we can stop antibiotic therapy when signs and symptoms have resolved in diabetic foot infection (DFI) patients with different grades of peripheral arterial disease (PAD) and those without PAD, and to determine whether the severity of PAD and infection has an effect on antibiotic therapy duration. A prospective randomized controlled trial of DFI patients was carried out. Patients were randomized into 2 groups when signs and symptoms had resolved: continuing antibiotics group (CAG) and discontinuing antibiotics group (DAG). The recurrence and clinical outcomes were recorded. The recurrence rate of mild infection with mild/moderate PAD was similar in the 2 groups. Compared with CAG, the recurrence rate of mild infection with severe PAD was higher in DAG (P = .030), also for moderate/severe infection with PAD (mild/moderate [P = .032]; severe [P = .008]). No difference was found in the 2 groups (either mild or moderate/severe) for those without PAD. The clinical outcomes of mild infection in patients were similar in the 2 groups. For moderate/severe infection, the healing rate was higher (73.3% vs 48.3%), and the rate of minor/major amputation and death was lower (23.8% vs 49.4%; 6.9% vs 20.7%; 2.0% vs 13.8%) in the CAG. When the clinical signs and symptoms of infection have resolved, it might be appropriate to stop antibiotics for DFI patients without PAD, and also for patients with mild infection with mild/moderate PAD. For patients with mild infection with severe PAD and moderate/severe infection with PAD, we should perhaps continue antibiotic treatment. Continuing antibiotic therapy could improve clinical outcomes for patients with moderate/severe infection.

Do Diabetic Foot Infections With Methicillin-Resistant Staphylococcus aureus Differ From Those With Other Pathogens?

There is controversy as to whether or not diabetic foot infections (DFIs) caused by methicillin-resistant Staphylococcus aureus (MRSA) are associated with worse outcomes than DFIs caused by other pathogens. To address this issue we performed a nonsystematic literature search of published articles in English language journals seeking studies reporting on the outcomes of DFIs related to their microbiology. We retrieved 48 articles published from 1999 to 2013 that described a total of 7771 cases of DFI. The overall proportion of DFIs with an isolate of S aureus was about 30%; just over one third of these (11% of all cases) were MRSA strains. Among the DFI cases caused by MRSA 1543 were episodes of soft tissue infections and 113 of osteomyelitis, while non-MRSA organisms caused 5761 soft tissue infections and 354 cases of osteomyelitis. Only 5 of the included articles attempted a comparison between DFI caused by MRSA and those caused by other pathogens, with no clear differences noted. The median total duration of antibiotic therapy for DFI caused by MRSA was 26 days, of which a median of 10 days was given intravenously. Only a few articles reported the proportion of patients with a recurrence, but they often did not differentiate between MRSA and non-MRSA cases. Four publications reported a worse functional or microbiological outcome in MRSA, compared to non-MRSA, cases, but the findings were variable and differences did not seem to be significant. Many trials failed to adjust for case-mix or to definitively demonstrate a relationship between microbiology and outcomes. Few of the articles specifically commented on whether the MRSA isolates were health care- or community-acquired strains. Notwithstanding the substantial limitations of the available literature, there does not appear to be a need for any special treatment for DFI caused by MRSA. The current guidelines for treating according to established international recommendations seem appropriate.