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

Abstract

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.

Assessment role of phagocytic neutrophil cells among different Wagner’s grades of diabetic foot ulcers infections

“…In our study, the diabetic patients have superficial wounds of Wagner's grades classification I and II were mostly infected with Gram positive bacteria. Staphylococci and Streptococci species were the predominant pathogens, whereas Gram negative bacteria were more frequently isolated from Wagner's wounds classification grades III and V. These findings are in agreement with various studies concluded that an increasing of Wagner's grades, the proportion of bacterial infections were increased [2,24,35,44,45]. However, the percentage of S. aureus decreased with increased Wagner's grades similar findings reported in other study [24].…”

“…In this study, vancomycin showed 83.3% sensitivity of Gram positive bacteria isolated. This similar to other studies 90.1% [55], 95% [36], 98.2% [24], while other study showed low sensitivity of vancomycin 44.5% [44]. However, other studies showed 100% of Gram positive bacteria susceptible to vancomycin [5,27,32,35,50,58].…”

“…The most common bacterial isolates from diabetic ulcers in this study were Staphylococci species 40.8% compatible to other findings showed that Staphylococci species accounted 43.37%[23], whereas Gram negative bacteria were the most frequently pathogenic agents reported in other studies 51%[24], 56.1%[25], 61%[26], 67%[27] and 51.2%[28].Interestingly, our study revealed high rate of S. aureus 14.3%, S. epidermidis 14.3%, S. saprophyticus 9.5% and MRSA 4.8%. These results were compatible with the findings of other studies showed that S. aureus 19.4%, S. epidermidis 18.4% and other Staphylococci species 3.6%[29], Other study showed the most commonly isolated S. aureus 30%, followed by S. saprophyticus 19% and S. epidermidis 10%[30].…”

“…Other study indicated that first generation of cephalosporin was sensitive 41.7% [43], 16.1% [32]. Other studies showed the sensitivity of cefadroxil to Gram negative bacteria was 44.4% [50] and 11% [24].…”

Diagnosis and Management of Diabetic Foot Infections

“…In India, DFIs commonly are caused by gram-negative bacilli (31). Furthermore, pathogens from India (32,33) and other developing nations, such as Egypt (24) and China (34), have become highly resistant to antimicrobials. DFIs in regions with warmer climates, including India, the Middle East, and Africa, most commonly are caused by P. aeruginosa (35), attributed in part to the warm, humid environment causing foot sweating, self-treatment with antimicrobials, and self-contamination from suboptimal perineal and hand hygiene (36,37).…”