Prevalence of antibiotic resistance in diabetic foot infections and reassessment of empiric antibiotic therapy protocols (Abstract)

Udovichenko Oleg, Gurevich Maxim, Lipman-Arens Shelly², Maree Elmalek Tarek, Grimblat Mila, Abu Mock Fadi, Modlig Amir, Avrumov Milana, Behrbalk Eyal.

¹Orthopedic Division, Hillel Yaffe Medical Center. Hadera, Israel.

²Infectious Diseases Unit, Hillel Yaffe Medical Center. Hadera, Israel.

 

Background:

Antibiotic (AB) resistance of causative pathogens in diabetic foot infections (DFI) is well known problem that needs constant monitoring.

Methods:

We analyzed 142 consecutive wound cultures in 115 admissions with moderate to severe diabetic foot infections in tertiary DF center in Mar/2025-Feb/2026. Culture obtaining (deep swab or tissue) and bacteriology studies (with antibiotic sensitivity testing in aerobes) were made according to the hospital protocol. Empiric AB therapy included Amoxicillin/clavulanate (CoAmoxi) in 74%, CoAmoxi+Ciprofloxacin (if AB resistance was clinically suspected) in 24%, others in 12%.

Results:

367 pathogens were revealed, median 2.6 (0-5) per culture. 32% of pathogens were Aerobic Gram-Pos, 44% - Gram-Neg, 23% - Anaerobes, 1% - Fungi. Negative were 2% of cultures.

Of all patients 36% had Multidrug-Resistant Organisms (MDRO). Species with basal AmpC production (Pseudomonas, Morganella, Enterobacter etc.) – 19% of all pathogens (73/367) and 44% of all patients.  MRSA represented 23% of all Staphylococcus aureus, ESBL – 6% of all Gram-Negatives.

Empiric AB therapy was changed/modified upon the culture results in 50% patients (for Co-Amoxi – in 45%, for CoAmoxi+Cipro – in 54%)

Second-line AB (cephalosporines 3^rd generation, carbapenems, Pip/Tazo) demonstrated high degree of sensitivity (from 82% in Cefotaxime to 96% in Meropenem, 100% in Linezolid), while Co-Amoxi was effective only against 44% of tested (estimation for all pathogens – 61%), Ciprofloxacin - against 69%.

Susceptibility to Azitromycin was 76%, Levofloxacin – 81%, Trim/Sulfamethoxazole – 77%, Clindamycin (in Staph) - 81%, Vancomycin (in Staph, Strep, Enterococcus) – 99%

Conclusions:

1). Gram-Neg bacteria were predominant in our cohort.

2). Prevalence of bacteria with acquired or natural multiple resistance to antibiotics in our cohort was quite high.

3). Efficacy of Co-Amoxi appeared to be low, that needs renewal of empiric AB protocol.

4). Taking into account growing AB-resistance of anaerobes, implementation of susceptibility testing in this group is reasonable.