Antimicrobial resistance in surgical infections: experience from open tibia fracture-related infection intraoperative tissue specimens

Abstract

Background Antimicrobial resistance in surgical infections is known to have significant morbidity and mortality in extreme cases on top of increased costs in medical expenditure. This study aimed to analyze antimicrobial resistance patterns of microbes in open tibia fracture-related infection (FRI) using intraoperative tissue samples. Methods Between January and June 2022, a descriptive cross-sectional observational study was conducted involving patients aged 18 and above with open tibial shaft fractures. Microbiological culture and sensitivity of three intraoperative deep tissue and bone samples taken by sterile techniques using separate instruments in patients with infection. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method along with biomechanical tests for microbial identification. Results Fifty-seven deep tissue samples were taken from 19 patients with FRI who underwent surgery during the study period were analyzed. Almost all (96.5%) intraoperative tissue samples were culture-positive identifying 73 bacterial isolates out of which 57.9% were polymicrobial. The most frequent isolated bacteria were Gram-negative bacteria 56 (76.7%) with a predominance of Proteus spp 13 (17.8%). Methicilin Resistance Staphyaureus comprised 12 (16.4%) of the isolates whereas Inducible Clindamycin resistance was identified in 8 (57.1%) of Staphyloccus aureus isolates. More than half of the isolates 30 (53.6%) comprised of Extended Spectrum Beta Lactamase producing bacteria. There was high resistance to Cephalosporins and Amoxyclavulanic acid as the efficacy was low ranging from 28.2, 27.8, and 30.0% for cefotaxime, ceftazidime and amoxicillin/clavulanic acid, respectively. Almost all Gram-negative bacteria 47 (83.9%) had multidrug resistance pattern except for Pseudomonas aureginosa that had 77.8 to 88.9% susceptibility to all tested antibiotics. Conclusion High resistance to cephalosporins in patients with delayed or late infection in open tibia FRI is alarming and further studies to establish causes are indicated.