Inflammatory markers as risk factors for infection with multidrug-resistant microbes in diabetic foot subjects

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.

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.

Metagenomic analysis reveals antibiotic resistance profiles in tissue samples from patients with diabetic foot infections

OBJECTIVES

Treating patients with diabetic foot infection (DFI) is challenging because of high rates of antibiotic resistance. Therefore, to administer a suitable antibiotic treatment, it is necessary to know the antibiotic resistance patterns in DFIs.

METHODS

To explore this question, we selected metagenomic data of 36 tissue samples from patients with DFI in the National Center for Biotechnology Information Sequence Read Archive database.

RESULTS

A total of 229 antibiotic-resistant gene (ARG) subtypes belonging to 20 ARG types were detected. The antibiotic resistome of 229 different genes in the tissue samples of patients with DFI comprised 24 core and 205 accessory resistance genes. Among the core antibiotic resistome, multidrug, tetracycline, macrolide-lincosamide-streptogramin, and beta-lactam resistance genes were the dominant categories. Procrustes analysis indicated that both the microbial community composition and mobile genetic elements (MGEs) were determinants of the ARGs. In the network analysis, 29 species were speculated to be potential hosts of 28 ARGs based on the co-occurrence results. Plasmids and transposons were the most common elements that co-occurred with ARGs.

CONCLUSIONS

Our study provided detailed information about antibiotic resistance patterns in DFI, which has practical implications for suggesting a more specific antibiotic choice.

Transcriptomic fingerprint of bacterial infection in lower extremity ulcers

Clinicians and researchers utilize subjective, clinical classification systems to stratify lower extremity ulcer infections for treatment and research. The purpose of this study was to examine whether these clinical classifications are reflected in the ulcer's transcriptome. RNA sequencing (RNA‐seq) was performed on biopsies from clinically infected lower extremity ulcers (n = 44). Resulting sequences were aligned to the host reference genome to create a transcriptome profile. Differential gene expression analysis and gene ontology (GO) enrichment analysis were performed between ulcer severities as well as between sample groups identified by k‐means clustering. Lastly, a support vector classifier was trained to estimate clinical infection score or k‐means cluster based on a subset of genes. Clinical infection severity did not explain the major sources of variability among the samples and samples with the same clinical classification demonstrated high inter‐sample variability. High proportions of bacterial RNA were identified in some samples, which resulted in a strong effect on transcription and increased expression of genes associated with immune response and inflammation. K‐means clustering identified two clusters of samples, one of which contained all of the samples with high levels of bacterial RNA. A support vector classifier identified a fingerprint of 20 genes, including immune‐associated genes such as CXCL8, GADD45B, and HILPDA, which accurately identified samples with signs of infection via cross‐validation. This study identified a unique, host‐transcriptome signature in the presence of infecting bacteria, often incongruent with clinical infection‐severity classifications. This suggests that stratification of infection status based on a transcriptomic fingerprint may be useful as an objective classification method to classify infection severity, as well as a tool for studying host–pathogen interactions.

Aerobic bacteria isolated from diabetic foot ulcers of Egyptian patients: types, antibiotic susceptibility pattern and risk factors associated with multidrug-resistant organisms

INTRODUCTION

Diabetic foot infection (DFI) is one of the common diabetic complications. Pathogens causing DFI and their antibiotic susceptibility vary with location. Therefore, empirical antibiotic therapy should be based on the pathogens that are most likely to be present. Aim: To identify the frequent aerobic bacteria causing DFI with detection of their antibiotic susceptibility to help clinicians in our community choose the best empirical antibiotic for DFI.

METHODS

Swabs were collected from 104 diabetic foot ulcers (DFUs). Aerobic bacterial cultures were done followed by bacterial identification and antibiotic susceptibility testing on VITEK® 2 system. Extended-spectrum beta-lacatamase (ESBL) detection was performed phenotypically and confirmed by multiplex-PCR for bla _CTX-M, bla _TEM, and bla _SHV genes.

RESULTS

Aerobic bacterial infection was detected in 82/104 (78.8%) of the DFUs. Gram-negative bacilli (GNB) were isolated more frequently (56.1%) than Gram-positive cocci (GPC) (43.9%). The most common single-isolated bacteria were K. pneumoniae (26.8%), S. aureus and coagulase negative staphylococci (22% for each). The only significant independent predictors of DFI with GNB or GPC were long DM duration and frequent hospitalizations, respectively. The most active antibiotics were amikacin, tigecycline and meropenem for GNB, and linezolid and vancomycin for staphylococci. Multidrug-resistance prevalence was 95.1%. ESBL was detected in 52.6% of Enterobacteriaceae; the bla _CTX-M gene was the most common (90%), followed by bla _TEM (65%) and bla _SHV (35%). Peripheral neuropathy was the single independent predictor for DFI with ESBL producers (adjusted OR=15.5).

CONCLUSIONS

There is a notable local pattern of DFI bacteriology in our community. Our findings could be valuable in developing the future empirical treatment guidelines for DFIs.

The Influence of Multidrug-Resistant Bacteria on Clinical Outcomes of Diabetic Foot Ulcers: A Systematic Review

Multidrug-resistant organism infections have become important in recent years due to the increased prevalence of diabetic foot ulcers and their possible consequences. This study aimed to systematically review and evaluate ulcer duration, healing time, hospital stay, amputation, and mortality rates in patients with diabetic foot ulcers caused by infection with multidrug-resistant organisms. PubMed, the Cochrane Library, and Web of Science were searched in May 2020 to find observational studies in English about the clinical outcomes of multidrug-resistant organism infection in diabetic foot ulcers. Eight studies met the inclusion criteria, and these studies included 923 patients. The overall methodological quality of the study was moderate. Ulcer duration was described in six studies, and there was no practical association with multidrug-resistant organisms. Two out of three studies reported a longer healing time in multidrug-resistant organism infections than in non-multidrug-resistant organism infections. Clinical outcomes included the duration of hospitalisation, surgeries, amputations, and deaths. Lower limb amputation was the most reported clinical outcome in the included studies, and was more prevalent in the multidrug-resistant organism infections. We concluded that there was not enough evidence that multidrug-resistant organisms hindered the healing of diabetic foot ulcers. In contrast to the clinical outcomes, multidrug-resistant organisms affect both amputation rates and mortality rates.

Antibiotic resistance in diabetic foot infection: how it changed with COVID-19 pandemic in a tertiary care center

AIM

To investigate the rate of antibiotic resistance and its main risk factors in a population of patients with diabetic foot infection (DFI) during the COVID-19 pandemic, in comparison with the population of 2019.

METHODS

Two hundred and twenty-five patients with DFI were admitted in a tertiary care center from January 2019 to December 2020. Antibiotic resistance was evaluated by microbiological examination of soft tissues' or bone's biopsy.

RESULTS

Compared with 2019 group (n = 105), 2020 group (n = 120) had a significantly higher prevalence of antibiotic resistance [2019 vs 2020, 36% vs 63%, P <0.001] and more often was admitted with recent or current antibiotic therapy (18% vs 52%, P <0.001), which was frequently self-administered (5% vs 30%, P = 0.032). The risk of antibiotic resistance was also higher in 2020 group [OR 95% CI, 2.90 (1.68 to 4.99)]. Prior hospitalization, antibiotic self-administration and antibiotic prescription by general practitioners resulted as independent predictors of antibiotic resistance.

CONCLUSIONS

In a population of people with DFI admitted in a tertiary care center during the COVID-19 pandemic the prevalence of antibiotic resistance was higher than 2019. Previous hospitalization, antibiotic self-administration /prescription by general practitioners were related to higher risk of antibiotic resistant infections.

Multicentre study of the burden of multidrug-resistant bacteria in the aetiology of infected diabetic foot ulcers

Background

Infected diabetic foot ulcer (IDFU) is a public health issue and the leading cause of non-traumatic limb amputation. Very few published data on IDFU exist in most West African countries.

Objective

The study investigated the aetiology and antibacterial drug resistance burden of IDFU in tertiary hospitals in Osun state, Nigeria, between July 2016 and April 2017.

Methods

Isolates were cultured from tissue biopsies or aspirates collected from patients with IDFU. Bacterial identification, antibiotic susceptibility testing and phenotypic detection of extended-spectrum beta-lactamase and carbapenemase production were done by established protocols. Specific resistance genes were detected by polymerase chain reaction.

Results

There were 218 microorganisms isolated from 93 IDFUs, comprising 129 (59.2%) Gram-negative bacilli (GNB), 59 (27.1%) Gram-positive cocci and 29 (13.3%) anaerobic bacteria. The top five facultative anaerobic bacteria isolated were: Staphylococcus aureus (34; 15.6%), Escherichia coli (23; 10.6%), Pseudomonas aeruginosa (20; 9.2%), Klebsiella pneumoniae (19; 8.7%) and Citrobacter spp. (19; 8.7%). The most common anaerobes were Bacteroides spp. (7; 3.2%) and Peptostreptococcus anaerobius (6; 2.8%). Seventy-four IDFUs (80%) were infected by multidrug-resistant bacteria, predominantly methicillin-resistant S. aureus and GNB producing extended-spectrum β-lactamases, mainly of the CTX-M variety. Only 4 (3.1%) GNB produced carbapenemases encoded predominantly by bla _VIM. Factors associated with presence of multidrug-resistant bacteria were peripheral neuropathy (adjusted odds ratio [AOR] = 4.05, p = 0.04) and duration of foot infection of more than 1 month (AOR = 7.63, p = 0.02).

Conclusion

Multidrug-resistant facultative anaerobic bacteria are overrepresented as agents of IDFU. A relatively low proportion of the aetiological agents were anaerobic bacteria.

Efficacy of Lytic Phage Cocktails on Staphylococcus aureus and Pseudomonas aeruginosa in Mixed-Species Planktonic Cultures and Biofilms

The efficacy of phages in multispecies infections has been poorly examined. The in vitro lytic efficacies of phage cocktails AB-SA01, AB-PA01, which target Staphylococcus aureus and Pseudomonas aeruginosa, respectively, and their combination against their hosts were evaluated in S. aureus and P. aeruginosa mixed-species planktonic and biofilm cultures. Green fluorescent protein (GFP)-labelled P. aeruginosa PAO1 and mCherry-labelled S. aureus KUB7 laboratory strains and clinical isolates were used as target bacteria. During real-time monitoring using fluorescence spectrophotometry, the density of mCherry S. aureus KUB7 and GFP P. aeruginosa PAO1 significantly decreased when treated by their respective phage cocktail, a mixture of phage cocktails, and gentamicin. The decrease in bacterial density measured by relative fluorescence strongly associated with the decline in bacterial cell counts. This microplate-based mixed-species culture treatment monitoring through spectrophotometry combine reproducibility, rapidity, and ease of management. It is amenable to high-throughput screening for phage cocktail efficacy evaluation. Each phage cocktail, the combination of the two phage cocktails, and tetracycline produced significant biofilm biomass reduction in mixed-species biofilms. This study result shows that these phage cocktails lyse their hosts in the presence of non-susceptible bacteria. These data support the use of phage cocktails therapy in infections with multiple bacterial species.

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.

Bacteriology of moderate-to-severe diabetic foot infections in two tertiary hospitals of Iran

BACKGROUND

Approximately 25% of people with diabetes will experience diabetic foot ulcers (DFUs) during their lifetime. The present study was designed to determine the type of microorganisms isolated from the DFUs and their antibiotic resistance pattern, and to determine predisposing factors contributing to antibiotic resistance at the authors' wound care clinic in Qazvin, Iran.

METHODS

A cross-sectional study was conducted from May to December 2017. One specimen for microbiological studies was obtained from the deep tissue. All demographic, clinical, and laboratory data and results of ulcer culture were collected for each case. Antimicrobial susceptibility testing to different agents was carried out using the disc diffusion method. A p value < 0.05 was considered significant.

RESULTS

95 aerobic microorganisms were isolated from 105 specimens. Among Gram-positive and negative bacteria, Staphylococcus spp. and Escherichia (E). coli were the most frequent organisms isolated, respectively. Multidrug resistant (MDR) organisms constituted up to 48.4%, with 37.5% of isolated Enterococcus spp. being VRE, 48.8% of Staphylococcus spp. being methicillin-resistant, 77.8% of isolated E. coli being ESBL and 66.7% of isolated Pseudomonas being MDR. The minimum and maximum prevalence of resistance in Gram-negative bacteria were 17.6% and 87.5% for imipenem and ceftazidime, respectively. The prevalence of Gram-negative bacilli was higher in older patients (p value = 0.039) and rose markedly in patients with a higher number of hospitalizations (p value = 0.015).

CONCLUSION

Due to emergence of antibiotic resistance pathogens, culture specimens and antibiotic sensitivity testing are essential for correct management of the DFU infections and the selection of appropriate antibiotics.

Synergistic in vitro effects of indocyanine green and ethylenediamine tetraacetate-mediated antimicrobial photodynamic therapy combined with antibiotics for resistant bacterial biofilms in diabetic foot infection

BACKGROUND

Antibiotic resistance has emerged as one of the most important determinants in diabetic foot infections outcomes. Antimicrobial Photodynamic therapy(A-PDT) or Photodynamic antimicrobial chemotherapy (PACT) has been proposed as an alternative approach for inactivating bacteria, especially resistant bacterial biofilms. This research investigated the synergistic effects of PACT mediated by the photosensitizer indocyanine green (ICG) and ethylenediamine tetraacetate (EDTA) combined with antibiotics against common pathogens of diabetic foot ulcer infection, including Staphylococcus aureus and Pseudomonas aeruginosa, in vitro.

METHODS

Planktonic bacteria and biofilms of S. aureus and P. aeruginosa were incubated with ICG and EDTA, and then exposed to laser treatment. Quantitative viable counting estimates the phototoxic effects on S. aureus and P. aeruginosa. The susceptibility of methicillin-resistant S. aureus (MRSA) and multidrug-resistant P. aeruginosa (MRPA) to PACT treatment was detected by disk diffusion and micro-broth dilution methods. Confocal microscopy was used to detect the morphology of biofilms treated with PACT and antibiotics. The resazurin assay was used to quantify the metabolic activity of bacteria in biofilms.

RESULTS

PACT mediated by ICG and EDTA led to a more pronounced antibacterial effect in S. aureus and P. aeruginosa compared with ICG alone-mediated PACT. P. aeruginosa was more sensitive to ICG and EDTA-mediated PACT than S. aureus. After PACT treatment, the susceptibility of MRSA and MRPA to antibiotics increased. Furthermore, PACT combined with antibiotic treatment significantly contributed to killing bacteria in the biofilm and disrupting biofilm structure.

CONCLUSIONS

ICG and EDTA-mediated PACT combined with antibiotics synergistically enhanced the effects of sterilization and biofilm destruction.