Distribution and drug sensitivity of pathogenic bacteria in diabetic foot ulcer patients with necrotizing fasciitis at a diabetic foot center in China

Global patterns of antibiotic resistance in group B Streptococcus: a systematic review and meta-analysis

Objectives

Streptococcus agalactiae, or group B Streptococcus (GBS), is a significant pathogen associated with severe infections in neonates, particularly sepsis and meningitis. The increasing prevalence of antibiotic resistance among GBS strains is a growing public health concern, necessitating a comprehensive meta-analysis to evaluate the prevalence of this resistance globally.

Methods

We conducted a comprehensive systematic search across four major scientific databases: Scopus, PubMed, Web of Science, and EMBASE, targeting articles published until December 13, 2023. This meta-analysis focused on studies that examined antibiotic resistance in GBS strains. The Joanna Briggs Institute tool was employed to assess the quality of the included studies. This meta-analysis applied a random-effects model to synthesize data on antibiotic resistance in GBS, incorporating subgroup analyses and regression techniques to explore heterogeneity and trends in resistance rates over time. Outliers and influential studies were identified using statistical methods such as Cook's distance, and funnel plot asymmetry was assessed to evaluate potential publication bias. All analyses were conducted using R software (version 4.2.1) and the metafor package (version 3.8.1).

Results

This study included 266 studies from 57 countries, revealing significant variability in GBS antibiotic resistance rates. The highest resistance rates were observed for tetracycline (80.1, 95% CI: 77.1-82.8%), while tedizolid (0.1, 95% CI: 0.0-0.8%) showed the lowest resistance rates. Significant heterogeneity in resistance rates was observed, particularly for antibiotics such as azithromycin and gentamicin (I 2 = 97.29%), variability across studies. On the other hand, tigecycline and ceftaroline exhibited no heterogeneity (I 2 = 0%), suggesting consistent resistance patterns. Subgroup analyses revealed disparities in resistance rates based on country, continent, and methodological categories. Significant increase in resistance rates for several antibiotics over time, including clindamycin, erythromycin, ceftriaxone, cefuroxime, ciprofloxacin, levofloxacin, moxifloxacin, chloramphenicol, and ofloxacin. Ofloxacin and cefuroxime showed particularly steep trends. Conversely, a declining resistance trend was observed for oxacillin.

Conclusion

This study emphasizes the growing issue of antibiotic resistance in GBS strains. Notable resistance to older and newer antibiotics, increasing resistance over time, regional disparities, and methodological variations are noted. Rising resistance trends for multiple antibiotics underscore the urgent need for global surveillance and improved antibiotic stewardship.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/view/CRD42024566269, CRD42024566269.

Diabetic foot ulcer in the Western Pacific Region: Current data on ulceration rates and microbial profiles, gaps and charting strategies

The Western Pacific Region hosts the largest proportion of people with diabetes. Despite being a key diabetes-related complication, diabetic foot ulcer has been neglected in both prevention and treatment efforts. This narrative review highlights available data on the burden (either prevalence or incidence), as well as microbial profiles of diabetic foot ulcers in the Western Pacific Region, identifies data gaps, and discusses strategies to address these gaps. There are substantial gaps in epidemiological data and microbial profiles for many countries in the Western Pacific Region. Addressing these gaps require developing and strengthening data collection systems for effective surveillance and benchmarking of diabetes care.

Synergistic Antibacterial Effect of Mucus Fraction from Cornu aspersum and Cirpofloxacin Against Pathogenic Bacteria Isolated from Wounds of Diabetic Patients

Background/Objectives: The treatment of diabetic foot ulcers (DFU) is a challenging medical problem of extreme clinical and social importance, as a consequence of the emerging antibiotic resistance and decreased quality of life of diabetic patients due to impaired wound healing. One of the current trends in world science is the search for biologically active substances derived from living organisms. Biologically active peptides from snail mucus attract considerable scientific interest because of their pleiotropic pharmacological properties. The aim of our study was to evaluate the activity of a combination between a snail mucus protein fraction (MW > 20 kDa) obtained from the garden snail Cornu aspersum and the clinically applied antibacterial chemotherapeutic ciprofloxacin on pathogenic bacterial strains isolated from DFU. Results: The test bacterial strains were characterized as multidrug resistant. The combination between ciprofloxacin and the snail mucus fraction of interest led to additive or synergistic effects depending on the test strain. The mucus fraction exerted a well-pronounced wound-healing effect and no cytotoxicity on normal human fibroblasts and keratinocytes. Methods: The snail mucus was obtained by a patented technology (BG Utility model 2097/2015) and its electrophoretic profile was presented by SDS-PAGE. The bacterial strains were identified and tested for antimicrobial susceptibility (BD Phoenix M50 and Kirby-Bauer assay). The in vitro cytotoxicity of the mucus was evaluated by ISO 10995-5. The antimicrobial activity and combination effects were tested through ISO 20776/1 and the Checkerboard assay. Conclusions: The obtained results are promising and open new horizons for the development of novel combination treatment schemas for healing of infected DFU.

Application of metagenomic next-generation sequencing (mNGS) to describe the microbial characteristics of diabetic foot ulcers at a tertiary medical center in South China

BACKGROUND

Diabetic foot ulcers (DFUs) are characterized by dynamic wound microbiome, the timely and accurate identification of pathogens in the clinic is required to initiate precise and individualized treatment. Metagenomic next-generation sequencing (mNGS) has been a useful supplement to routine culture method for the etiological diagnosis of DFUs. In this study, we utilized a routine culture method and mNGS to analyze the same DFU wound samples and the results were compared.

METHODS

Forty samples from patients with DFUs at a tertiary medical center in South China were collected, the microorganisms were identified with mNGS and routine culture method simultaneously.

RESULTS

The results showed that the positive detection rate of microorganisms in DFUs with mNGS was much higher (95% vs. 60%). Thirteen strains of microorganisms were detected with routine culture method, and seventy-seven strains were detected with mNGS. Staphylococcus aureus was the most common microorganism detected with culture method, while Enterococcus faecalis was the most common microorganism detected with mNGS. The false negative rate of the culture method was 35%, that was, 14 samples with negative results with culture method were found to be positive with mNGS.

CONCLUSION

The mNGS method had a higher positive detection rate and identified a broader spectrum of microorganisms in DFUs, thus, mNGS provided a more comprehensive understanding of the microbiome of DFUs to facilitate the development of timely and optimal treatment.

TRIAL REGISTRATION

The study was conducted in accordance with the Declaration of Helsinki and approved by the Ethical Review Committee of the Fujian Medical University Union Hospital (approval number 2021KY054).

Identification and treatment of Enterococcus avium-induced diabetic foot ulcer: a case report and microbiome analysis

Abstract

Diabetic foot ulcer (DFU) is a severe complication of diabetes. Due to conservative or delayed treatment, the majority of DFU patients frequently miss the optimal treatment window, thereby leading to amputation. Despite being a rare pathogen with low virulence, Enterococcus avium (E. avium) exhibits some antibiotic resistance and can be fatal for immunocompromised patients. This report describes a DFU case, caused by E. avium infection due to exposure to poultry. Wound microbiota was dynamically monitored using bacterial culture followed by 16S rRNA gene sequencing throughout the illness. Combination of antibiotics was administered to control the secondary infection.

Case report

A 56-year-old man presented with a two-week history of redness, swelling, heat, pain, and pus discharge from a ruptured wound on his left heel. The patient was diagnosed with osteomyelitis and a Wagner grade 3 diabetic foot ulcer infection, complicated by the soft tissue infection in the left heel. Strain identification and antibiotic susceptibility tests were immediately performed after admission. The patient underwent three debridement procedures at the DFU site. However, we observed recurrent bacterial infections, based on the clinical progression. Second-generation sequencing detected various pathogens. After targeted treatment with Vacuum sealing drainage (VSD) combined with antibiotic bone cement, the patient's condition stabilised. A skin graft was subsequently performed. Antibiotics were used to control the infection and blood glucose level was controlled throughout the treatment.

Conclusion

Thus, this report provides a comprehensive description of a DFU case, caused by E. avium. Antibiotics and surgical measures should be adjusted according to the pathogens responsible for wound infections in DFU patients. It is important to reduce the mortality and prevent irreversible amputations.

Prospective Observational Study of Microbiology of Infected Diabetic Foot Ulcers in a Tertiary-Care Hospital

INTRODUCTION

 Diabetic foot ulcers (DFUs) are a major cause of morbidity and mortality in people with diabetes mellitus. DFUs are the leading cause of hospitalisation for diabetic patients worldwide, especially in developing countries such as India. This study presents the microbiology profile of DFUs in a tertiary care hospital in the eastern part of India.

METHODOLOGY

 We conducted a prospective observational study for 150 DFU patients over a period of two years. We took samples from the DFUs of these patients, cultured them, and tested their antimicrobial susceptibility.

RESULTS

 Most diabetic foot infections (DFIs) in our study patients were caused by Gram-negative bacteria, mainly Escherchia coli (E. coli) (19.3%), Pseudomonas (14%), and Staphylococcus aureus (S. aureus) (12%). The majority of Gram-positive bacteria were susceptible to linezolid, followed by vancomycin and amoxycillin, while the majority of Gram-negative bacteria were susceptible to imipenem and meropenem, followed by ampicillin with sulbactam, amikacin, gentamicin, and ciprofloxacin. Our study revealed that 88.3% of the isolates were monomicrobial.

CONCLUSION

These findings demonstrated the importance of a local antibiogram, a microbiological exam, and antimicrobial susceptibility testing before starting antibiotic treatment for infections caused by DFUs. This protocol is different from the recommended guidelines for using empirical antibiotics.

A systematic review of diabetic foot infections: pathogenesis, diagnosis, and management strategies

Background

Diabetic foot infection represents a significant complication of diabetes mellitus, contributing substantially to morbidity, mortality, and healthcare expenditure worldwide. Accurate diagnosis relies on a comprehensive assessment integrating clinical evaluation, imaging studies, and microbiological analysis. Management necessitates a multidisciplinary approach, encompassing surgical intervention, antimicrobial therapy, and advanced wound care strategies. Preventive measures are paramount in reducing the incidence and severity, emphasizing patient education, regular foot screenings, and early intervention.

Methods

The researchers performed a systematic review of literature using PUBMED MESH keywords. Additionally, the study was registered in the International Prospective Register of Systematic Reviews at the Center for Reviews and Dissemination, University of York (CRD42021277788). This review provides a comprehensive overview of the microbial spectrum and antibiotic susceptibility patterns observed in diabetic foot infections.

Results

The search through the databases finally identified 13 articles with 2545 patients from 2021 to 2023. Overall, the predominant Gram-positive microbial species isolated were Staphylococcus aureus, Enterococcus fecalis, Streptococcus pyogenes, Streptococcus agalactiae, and Staphylococcus epidermidis. Whereas the predominant Gram-negative included Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Pseudomonas aeruginosa.

Conclusion

Diabetic foot infections represent a complex and multifaceted clinical entity, necessitating a holistic approach to diagnosis, management, and prevention. Limited high-quality research data on outcomes and the effectiveness of guideline recommendations pose challenges in updating and refining existing DFI management guidelines.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021277788, identifier CRD42021277788.

Prevalence of multidrug-resistant bacterial infections in diabetic foot ulcers: A meta-analysis

Multidrug-resistant (MDR) bacterial infections have become increasingly common in recent years due to the increased prevalence of diabetic foot ulcers (DFUs). We carried out a meta-analysis aimed at investigating the prevalence of MDR bacteria isolated from DFUs and analysing the risk factors for MDR bacterial infection in patients with DFUs. The PubMed/Medline, Web of Science, Embase, Cochrane Library, Ovid, Scopus, and ProQuest databases were searched for studies published up to November 2023 on the clinical outcomes of MDR bacteria in DFUs. The main outcome was the prevalence of MDR bacteria in DFUs. A total of 21 studies were included, representing 4885 patients from which 2633 MDR bacterial isolates were obtained. The prevalence of MDR bacteria in DFUs was 50.86% (95% confidence interval (CI): 41.92%-59.78%). The prevalence of MDR gram-positive bacteria (GPB) in DFUs was 19.81% (95% CI: 14.35%-25.91%), and the prevalence of MDR gram-negative bacteria (GNB) in DFUs was 32.84% (95% CI: 26.40%-39.62%). MDR Staphylococcus aureus (12.13% (95% CI: 8.79%-15.91%)) and MDR Enterococcus spp. (3.33% (95% CI: 1.92%-5.07%)) were the main MDR-GPB in DFUs. MDR Escherichia coli, MDR Pseudomonas aeruginosa, MDR Enterobacter spp., MDR Klebsiella pneumoniae, and MDR Proteus mirabilis were the main MDR-GNB in DFUs. The prevalence rates were 6.93% (95% CI: 5.15%-8.95%), 6.01% (95% CI: 4.03%-8.33%), 3.59% (95% CI: 0.42%-9.30%), 3.50% (95% CI: 2.31%-4.91%), and 3.27% (95% CI: 1.74%-5.21%), respectively. The clinical variables of diabetic foot ulcer patients infected with MDR bacteria and non-MDR bacteria in the included studies were analysed. The results showed that peripheral vascular disease, peripheral neuropathy, nephropathy, osteomyelitis, Wagner's grade, previous hospitalization and previous use of antibacterial drugs were significantly different between the MDR bacterial group and the non-MDR bacterial group. We concluded that there is a high prevalence of MDR bacterial infections in DFUs. The prevalence of MDR-GNB was greater than that of MDR-GPB in DFUs. MDR S. aureus was the main MDR-GPB in DFUs, and MDR E. coli was the main MDR-GNB in DFUs. Our study also indicated that peripheral vascular disease, peripheral neuropathy, nephropathy, osteomyelitis, Wagner's grade, previous hospitalization, and previous use of antibacterial drugs were associated with MDR bacterial infections in patients with DFUs.

Enterococci facilitate polymicrobial infections

Enterococci are ubiquitous members of the gut microbiota in human beings and animals and are among the most important nosocomial organisms. Due to their opportunistic pathogenicity, enterococci are referred to as pathobionts and play decisive roles in a diverse array of polymicrobial infections. Enterococci can promote the colonization, pathogenesis, and persistence of various pathogens, compromise the efficacy of drugs, and pose a severe threat to public health. Most current treatments tend to focus on the sole pathogenic bacteria, with insufficient attention to the driving role of enterococci. In this review, we summarize the characteristics of enterococci in infections, the factors facilitating their outgrowth, as well as the sites and types of enterococci-associated polymicrobial infections. We present an overview of the underlying mechanisms of enterococci-mediated pathogenesis in polymicrobial infections. Furthermore, we discuss alternative strategies and potential intervention approaches to restrict such infections, shedding light on the discovery and development of new therapies against polymicrobial infections.

Successful Outpatient Treatment of Severe Diabetic-Foot Myositis and Osteomyelitis Caused by Extensively Drug-Resistant Enterococcus faecalis with Teicoplanin plus Rifampicin: A Case Report

BACKGROUND Foot ulcers are high-morbidity and debilitating complications of diabetes mellitus, and carry significantly increased rates of associated major amputations. They contribute to significantly worse quality of life. Osteomyelitis is a frequent complication of diabetic foot ulcers, since bacteria can contiguously spread from soft tissues to the bone, involving the cortex first and then the bone marrow. Unfortunately, clinically unsuspected osteomyelitis is frequent in persisting diabetic foot ulcers. It is associated with limb amputations and increased mortality. CASE REPORT We describe a 76-year-old man with long-standing insulin-treated type 2 diabetes, who experienced extensively drug-resistant Enterococcus faecalis diabetic foot myositis and osteomyelitis associated with sepsis. He was successfully treated with surgical debridement combined with the administration of teicoplanin plus rifampicin in the outpatient setting, completing, in total, a twelve-week course of antibiotic therapy. CONCLUSIONS Clinically unsuspected osteomyelitis in patients with persisting diabetic foot ulcers has been associated with infections from highly resistant bacteria. Early and accurate diagnosis of diabetic foot osteomyelitis, as well as proper therapeutic approach (antimicrobial and surgical), is of great importance to reduce the risk of minor and major amputations, septic shock leading to multiple organ failure, and overall mortality.

Interspecies Interactions within the Host: the Social Network of Group B Streptococcus

Group B Streptococcus (GBS) is a pervasive neonatal pathogen accounting for a combined half a million deaths and stillbirths annually. The most common source of fetal or neonatal GBS exposure is the maternal microbiota. GBS asymptomatically colonizes the gastrointestinal and vaginal mucosa of 1 in 5 individuals globally, although its precise role in these niches is not well understood. To prevent vertical transmission, broad-spectrum antibiotics are administered to GBS-positive mothers during labor in many countries. Although antibiotics have significantly reduced GBS early-onset neonatal disease, there are several unintended consequences, including an altered neonatal microbiota and increased risk for other microbial infections. Additionally, the incidence of late-onset GBS neonatal disease remains unaffected and has sparked an emerging hypothesis that GBS-microbe interactions in developing neonatal gut microbiota may be directly involved in this disease process. This review summarizes our current understanding of GBS interactions with other resident microbes at the mucosal surface from multiple angles, including clinical association studies, agriculture and aquaculture observations, and experimental animal model systems. We also include a comprehensive review of in vitro findings of GBS interactions with other bacterial and fungal microbes, both commensal and pathogenic, along with newly established animal models of GBS vaginal colonization and in utero or neonatal infection. Finally, we provide a perspective on emerging areas of research and current strategies to design microbe-targeting prebiotic or probiotic therapeutic intervention strategies to prevent GBS disease in vulnerable populations.

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.

Infection of Diabetes Foot Caused by Carbapenem-Resistant Proteus penneri Mediated by a Novel Plasmid Containing blaNDM

Objective

A strain of Proteus penneri with carbapenem resistance was found in a patient with a diabetic foot infection. We studied drug resistance, genome, and homology of P. penneri to support clinical prevention and treatment of infection caused by carbapenem-resistant P. penneri (CR-PPE).

Methods

The strains were obtained through bacterial culture from purulence. VITEK 2 compact (GN13) and Kirby-Bauer (K-B) disk diffusion methods were used for antimicrobial susceptibility testing. Ceftriaxone, amikacin, gentamicin, ampicillin, aztreonam, ceftazidime, ciprofloxacin, levofloxacin, cefepime, trimethoprim-sulfamethoxazole, tobramycin, cefotetan, piperacillin-tazobactam, ampicillin-sulbactam, ertapenem, piperacillin, meropenem, cefuroxime, cefazolin, cefoperazone/sulbactam, cefoxitin, and imipenem were used for antimicrobial susceptibility testing. After bacterial genome extraction, sequencing, and sequence assembly, whole-genome sequencing (WGS) was performed to explore the CR-PPE genotype.

Results

CR-PPE was resistant to two carbapenems (imipenem and ertapenem), ceftriaxone, and cefazolin, and was sensitive to aztreonam, piperacillin-tazobactam, and cefotetan. WGS results depict that the resistant phenotype of CR-PPE is consistent with the genotype, without common virulence genes of Enterobacteriaceae bacteria detected (virulence factor database). The carbapenem resistance gene blaNMD-1 is contained in a new plasmid, pWF127-NDM. The transposon Tn125 in pWF127-NDM carrying blaNMD-1 has almost the same structure as Tn125 in the reference plasmid pHFK418-NDM (Accession: MH491967). In addition, through phylogenetic analysis, CR-PPE depicts the closest evolutionary relationship with GCF 024129515.1, which was found in Gallus gallus in the Czech Republic in 2019 (downloaded from National Center for Biotechnology Information database). According to the evolutionary tree, CR-PPE has high homology with the two P. penneri strains found in China.

Conclusion

CR-PPE exhibits strong drug resistance owing to the presence of multiple resistance genes. CR-PPE infection should receive more attention, especially in patients with underlying diseases, such as diabetes and weak immunity.

Molecular epidemiology, drug resistance, and virulence gene analysis of Streptococcus agalactiae isolates from dairy goats in backyard farms in China

Streptococcus agalactiae infections may lead to clinical or subclinical mastitis in dairy animals when it invades the mammary gland. In this study, 51 S. agalactiae strains were isolated from 305 milk samples that were collected from goats with mastitis in 13 provinces of China. The antimicrobial resistance of S. agalactiae was determined by disk diffusion methods against 18 antibiotics from six classes. In addition, multilocus sequence typing (MLST), and the presence of resistance and virulence genes was determined by PCR analysis. Seven sequence types in five clonal complexes were identified according to MLST; CC103 and CC67 strains were predominant, with rates of 45.1% and 39.2%, respectively. All isolates (100%) were multiresistant to three or more antimicrobial agents. S. agalactiae isolates had a 100% resistance rate to penicillin, oxacillin, and amoxicillin, followed by doxycycline (82.4%), tetracycline (76.5%), and amikacin (74.5%). The lowest resistance was observed for ciprofloxacin (29.4%), which varied in five different regions. The detection rates of six classes of antimicrobial-related genes were calculated as follows: 33 (64.7%) for β-lactam-related resistance gene, 12 (23.5%) for tetracyclines, 11 (21.6%) for quinolone-related resistance genes, 10 (19.6%) for aminoglycosides, 7 (13.7%) for macrolides (ermA, ermB, and mefA), and 3 (5.9%) for lincosamide (lnu(B)). Regarding virulence genes, profile 1 (bca cfb-cspA-cylE-hylB-bibA-pavA-fbsA-fbsB) was the most prevalent, with a detection rate of 54.9%. This work provides a primary source related to the molecular epidemiology of S. agalactiae in dairy goat herds in China and will aid in the clinical treatment, prevention, and control of mastitis.

Difficulties in the Treatment of Diabetic Foot and Research Progress of Combination of Traditional Chinese and Western Medicine

A diabetic foot is any disorder directly attributable to peripheral arterial disease (PAD) and/or the sensory neuropathies influencing the diabetic foot; it is a long-term (or “chronic”) complication of diabetes. Generally, it is a permanent (or “chronic”) comorbidity of diabetes. The swallowing of peripheral neuropathy and peripheral vascular disease leads to damage to the soft tissue, bone, and joint system of the foot. In addition, diabetic feet are also susceptible to infection, which can lead to lameness and even amputation. The management of the diabetic foot can be both challenging and chronic; it may comprise orthoses, surgery, antibacterial medication, and topical dressings. Traditional Chinese medicine (TCM) has a variety of methods for the treatment of diabetic foot with obvious advantages, which can be divided into internal treatment and external treatment of TCM. These treatments include external foot bath, fumigation and washing stains, internal administration of traditional Chinese medicine, syndrome differentiation and staging treatment, empirical prescription, self-made prescription, internal use of proprietary Chinese medicine, massage, acupuncture, and paste powder application, which have significant value in the prevention and treatment of diabetic foot. Some studies have shown that modern medicine combined with herbal therapy can significantly improve the prognosis of diabetic foot. Therefore, this study summarized the difficulties in the therapeutic approaches to diabetic foot and the recent research progress in combining Chinese and Western medicine in the treatment of diabetic foot.