Microbiologic Analysis of Hand Infections: A Prospective Study.

Abstract

Background: Hand infections are a common problem in emergency departments. Staphylococcus aureus is the main pathogen of both hand and blood stream infections. Therefore, the aim of the present study was to evaluate the frequency and impact of bacteremia in patients with hand infections to improve the microbiologic diagnostics. Patients and Methods: A prospective study of 90 patients with acute hand infections without antimicrobial pre-treatment was performed. Blood cultures were taken pre-operatively. If positive, transesophageal echocardiography was performed to rule out infectious endocarditis. Tissue samples were microbiologically processed using standardized culture media. If negative, a broad-spectrum bacterial 16S ribosomal RNA (rRNA) gene polymerase chain reaction (PCR) was applied. The etiology and location of the infection, the length of hospital stay, the number of surgical interventions, and the inflammatory parameters were obtained. Results: Six patients with bacteremia (6.6%) were diagnosed, after animal bites (n = 3) and intra-articular empyema (n = 3). Pathogens included Staphylococcus pettenkoferi, Pasteurella multocida, Staphylococcus epidermidis, Staphylococcus aureus, and Bacteroides pyogenes. No case of infective endocarditis was detected. Patients with bacteremia required more surgical interventions (p = 0.002), had a longer hospital stay (p < 0.001), higher plasma C-reactive protein (CRP; p = 0.016), and a higher age (p = 0.002) compared with those without bacteremia. In 14 cases (15.6%) no pathogen was detected by culture, whereas the subsequent broad-spectrum PCR diagnosed three cases (21.4%). Conclusions: Pre-operative blood cultures in patients with hand infections are important to detect bacteremia as an essential marker of clinical severity. Those blood cultures are indicated after deep animal bites and joint empyema. A precise identification of pathogens is fundamental for an effective treatment of hand infections, for which a 16S rRNA gene PCR can contribute in culture-negative tissue samples.