# Microbiological Spectrum and Antimicrobial Resistance Patterns in Hand Surgery Infections: A Monocentric Retrospective Study

## TL;DR

This study examines bacteria causing hand surgery infections and their resistance to antibiotics, finding distinct patterns depending on the type of infection.

## Contribution

The study provides novel microbiological and resistance data specific to hand surgery infections, an area with limited prior research.

## Key findings

- Trauma-related infections were most common, often caused by Staphylococcus aureus with 25% methicillin resistance.
- Infections with internal fixation devices showed higher polymicrobial complexity.
- High-level antimicrobial resistance, such as extended-spectrum beta-lactamase or carbapenem resistance, was uncommon across all cases.

## Abstract

Background: Infections in hand surgery represent a clinically relevant complication, particularly in trauma-related procedures and in the presence of internal fixation devices. Data specifically addressing microbiological profiles and antimicrobial resistance patterns in hand surgery remain limited. Methods: A monocentric retrospective observational study was conducted, including 72 patients treated for hand surgery infections between January 2024 and June 2025. Microbiological isolates and antimicrobial susceptibility profiles were analyzed and stratified according to the clinical scenario, including trauma-related infections and infections associated with internal fixation devices. Monomicrobial and polymicrobial infections were evaluated separately. Results: Trauma-related infections accounted for 77.8% of cases, of which 64.3% were monomicrobial and 35.7% polymicrobial. Monomicrobial trauma-related infections were predominantly caused by Staphylococcus aureus, with methicillin resistance detected in 25.0% of cases. Polymicrobial trauma-related infections showed greater microbiological complexity but limited antimicrobial resistance. Infections associated with internal fixation devices represented 22.2% of cases and demonstrated a higher proportion of polymicrobial infections. Across all subgroups, no extended-spectrum beta-lactamase–producing Enterobacterales or carbapenem-resistant organisms were identified. Conclusions: This study fills an important evidence gap by characterizing pathogens and antimicrobial resistance in a dedicated hand surgery cohort, an area where published microbiological data remain limited compared with other orthopedic subspecialties. Hand surgery infections exhibit distinct microbiological and resistance profiles depending on the clinical scenario and microbial complexity. Despite frequent polymicrobial involvement, high-level antimicrobial resistance remains uncommon, supporting the value of local microbiological surveillance to guide empirical therapy.