Authors: Nathan Hoekzema MD*, Mohanad Bakleh MD, MIr Ali, MD PhD, Alexander Shin MD, Douglas Osmon MD
Title: The Microbiology of Agricultural Upper Extremity Trauma
Addresses: Mayo Clinic Department of Orthopaedic Surgery, 200 first ST SW, Rochester, MN, 55905
Purpose: The purpose of this study is to determine the microbiology of upper extremity wounds, to ascertain if the development of clinical infections is related to wound severity, and to determine if organisms isolated at the time of initial treatment and subsequent infections were susceptible in vitro to prophylaxis.
Methods: A retrospective chart review of 214 patients. Inclusion criteria included open wounds, upper extremity, agricultural etiology, and initial treatment at our institution. Information on patient demographics, injury specifics, treatments, and culture results were recorded. Wounds were classified on a new grading scale from 1-3, one being the least severe and three being the most severe.
Results: Wound types were 12.1% type one injury, 43.9% type two, and 43.9% type three. The most common microbiology was Coag negative Staph, with the second most common being Enterobacter. 18.7% of patients had some form of infective complication. 7.9% had cellulitis, 7.5% had deep soft tissue infections, and 3.3% with osteomyelitis. 2.8% went on to an amputation due to infection; 1.4% of those were below elbow amputations (all were type 3), 0.9% digit amputations (all Type 2), and 0.5% digital revision amputation due to infection (Type 3). There was 1 Flap failure due to infection (Type 3). Of patients that developed infection (40) and had positive fungi cultures (13), 10 were Type 3, 3 were Type 2, and no Type 1.
Discussion: In review of the in vitro susceptibilities, 90% patients that developed clinical infection had organisms resistant to the prophylactic regimen. We recommend wide spectrum antibiotic prophylaxis and thorough surgical debridement(s), especially for our Type 3 injuries. Due to the lack of control groups in our study, we are unable to suggest a specific prophylactic medication. We can; however, based on our data, suggest an empiric treatment scheme for a clinical infection. Based on the culture and sensitivity results we would suggest an initial regimen that is active against Staphylococci, Pseudomonas aeruginosa, Enterobacter, and anaerobes.
The exact medications used should be tailored to one's institution based on local resistance patterns and hospital formulary. The high numbers of Stenotrophomonas in our series would need adjunctive coverage such as Clavulanate/Ticarcillin (Timentin) or Sulfamethoxazole/Trimethoprim (Bactrim).
Infections in these types of wounds can be very complicated and a multidisciplinary approach including infectious disease specialists and surgeons is mandatory.
