Determination of Antimicrobial Resistance Patterns in Bacterial Isolates from Wound Swabs atDodoma Regional Referral Hospital, Tanzania

Abstract

Background: Bacterial infections in wounds pose significant challenges in healthcare, contributing to increased morbidity, mortality, and healthcare costs. Monitoring antimicrobial resistance (AMR) patterns among key pathogens such as Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus isolated from wound swabs are essential for effective infection control and appropriate treatment. Understanding AMR trends, particularly at Dodoma Referral Hospital, can inform treatment decisions and improve patient outcomes. This study aims to evaluate AMR patterns in bacterial isolates from wound swabs in order to optimise treatment strategies and enhance the quality of healthcare delivery.
Methods: In a retrospective cross-sectional study, we gathered information on wound swab samples from records maintained by the microbiology laboratory. The study also involved a review of 2,045 patient databases and files for individuals admitted to surgical wards or who visited the surgical clinic at Dodoma Regional Referral Hospital between 2020 and 2024.
Results: Between 2020 and 2024, the DRRH microbiology laboratory collected 2,045 wound swab samples, primarily from inpatients. The number of inpatient samples was 156 (54.7%) in 2020, 239 (66.8%) in 2021, 243 (62.5%) in 2022, 328 (52.3%) in 2023, and 172 (44.6%) in 2024, showing a predominance of male patients. Single-isolate growth rates increased over the years, from 255 (89.5%) in 2020 to 338 (87.6%) in 2024. The most frequently tested antimicrobials were meropenem (1145 tests, 66.0%), amikacin 1066 (60.5%), and gentamicin 989 (56.7%). Bacterial resistance patterns varied: Escherichia coli showed 121 (76%) resistance to ceftriaxone and 21 (7%) to meropenem; Pseudomonas aeruginosa had 27 (14%) resistance to amikacin; Klebsiella pneumoniae showed 128 (82%) resistance to ceftriaxone; and Staphylococcus aureus exhibited 5 (9%) resistance to trimethoprim/sulfamethoxazole and 78 (44%) to gentamicin.
Conclusion: Staphylococcus aureus is a priority Gram-positive bacterium that generally demonstrates lower levels of antimicrobial resistance compared to Gram-negative species such as Escherichia coli and Pseudomonas aeruginosa. These gram-negatives exhibit high resistance rates to ceftriaxone, but carbapenems and aminoglycosides remain effective. Strong infection prevention measures and tailored treatment strategies are essential.