Prevalence of Multidrug-resistant Bacteria Isolated from Diabetic Foot Infections at the Clinical Bacteriology Unit of the Institut Pasteur de Côte d’Ivoire, 2019–2022

Abstract

Background: Diabetic foot infections are associated with bacterial diversity and antimicrobial resistance, complicating empirical treatment. Aims: To describe the bacterial profile and antimicrobial resistance phenotypes of bacteria isolated from diabetic foot infections (DFIs) in Abidjan to inform local empirical antibiotic therapy. Study Design: Retrospective, cross-sectional, laboratory-based study. Place and Duration of Study: Clinical Bacteriology Unit, Department of Bacteriology-Virology, Institut Pasteur de Côte d'Ivoire, Abidjan, Côte d'Ivoire, from January 2019 to December 2022. Methodology: All patients with a culture-positive pus swab from a diabetic foot lesion were included. Isolates were identified by conventional phenotypic methods and API galleries. Antimicrobial susceptibility was determined by disc diffusion on Mueller-Hinton agar and interpreted according to the EUCAST breakpoints in force each year. Extended-spectrum β-lactamase (ESBL) production and methicillin resistance were detected phenotypically. Proportions are reported with 95% confidence intervals (CIs). Results: Ninety-five patients were included (60 men, 63.2%; mean age 47.6 years), with 95 isolates tabulated for analysis. Staphylococcus spp. accounted for 37 isolates (38.9%; S. aureus 31, 32.6%), Enterobacterales for 31 (32.6%; Escherichia coli 14, 14.7%) and non-fermenting Gram-negative bacilli for 27 (28.4%; Pseudomonas aeruginosa 23, 24.2%). Among Enterobacterales, 10/31 (32.3%; 95% CI 18.6–49.9) produced an ESBL, 10/31 (32.3%) were resistant to fluoroquinolones and 2/31 (6.5%) to imipenem. Methicillin resistance was found in 13/37 staphylococci (35.1%; 95% CI 21.8–51.2). Among P. aeruginosa, 2/23 (8.7%) were resistant to imipenem and none to amikacin; ceftazidime resistance was 8/23, 34.8%. Selected paired co-resistance profiles occurred in 1/37 staphylococci (2.7%), 1/31 Enterobacterales (3.2%), 2/23 P. aeruginosa isolates (8.7%) and 1/4 Acinetobacter spp. isolates (25.0%); these observations alone do not establish overall MDR prevalence. Conclusion: ESBL production was observed in 32.3% of Enterobacterales and methicillin resistance in 35.1% of staphylococci. Imipenem resistance was less frequent among Enterobacterales and P. aeruginosa, and no amikacin resistance was detected in P. aeruginosa. Systematic culture with susceptibility testing, periodic local surveillance and empirical regimens adapted to this resistance profile are needed.