Evaluation of Adherence to the Oral Antibiotic Treatment in Patients With Diabetic Foot Infection

Bacterial Diversity and Antibiotic Resistance in Patients with Diabetic Foot Osteomyelitis

This study analysed the bacterial diversity, antibiotic susceptibility, and resistance in patients with complications of diabetic foot osteomyelitis (DFO). A retrospective observational study was carried out between September 2019 and September 2022 and involved 215 outpatients with a diagnosis of DFO at a specialized diabetic foot unit. A total of 204 positive bone cultures were isolated, including 62.7% monomicrobial cultures, and 37.3% were formed with at least two microorganisms. We observed that Proteus spp., Coagulase-negative staphylococci (CoNS), Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Corynebacterium were the most frequently isolated microorganisms and accounted for more than 10% of the DFO cases. With stratification by Gram-positive (GP) and Gram-negative (GN) bacteria, we observed that 91.6% of cultures presented at least one GP bacteria species, and 50.4% presented at least one GN bacteria species. The most common GP species were CoNS (29%), S. aureus (25.8%), and Corynebacterium spp. (14%). The most frequent GN species consisted of Proteus spp. (32%), P. aeruginosa (23.3%), and E. coli (17.5%). The main antibiotics with resistance to GP-dominated infections were penicillins without β-lactamase inhibitor, and those in GN-dominated infections were sulfonamides and penicillins without β-lactamase. Significant differences were not observed in mean healing time in DFU with acute osteomyelitis (12.76 weeks (4.50;18)) compared to chronic osteomyelitis (15.31 weeks (7;18.25); p = 0.101) and when comparing cases with soft tissue infection (15.95 (6;20)) and those without such an infection (16.59 (7.25;19.75), p = 0.618). This study shows that when treatment of DFO is based on early surgical treatment, the type of DFO and the presence of soft infection are not associated with different or worse prognoses.

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.