Posttraumatic bacterial infections in extremities before and after osteosynthesis in dogs

ABSTRACT

Background: Posttraumatic osteomyelitis is one of the most serious complications after fracture treatment. Although haematogenous osteomyelitis is fairly common in man, it is rarely seen in small animal orthopedic surgery. Predisposing factors to osteomyelitis include bacterial contamination in combination with severe trauma, surgical intervention, the presence of dead bone, or metallic implants, especially if bone or implants are unstable. Posttraumatic osteomyelitis is nearly always infectious in etiology, caused by various pathogens. The purpose of this present study is to find out the type of aerobic bacteria, which plays an important role in the posttraumatic infection before and after fracture osteosynthesis. Materials, Methods & Results: Our study was performed on 15 patients with long bone fractures operated at the Department of Surgery, Small Animal Clinic, University of Adnan Menderes, Aydin. The patients without an antibiotic treatment 24 h prior to surgery were included in the study. Our study was performed on 15 patients who had undergone osteosynthesis in extremities at Department of Surgery, Small Animal Clinic, University of Adnan Menderes, Aydin. The patients without antimicrobial treatment 24 h before surgery were included in our study. The osteosynthesis procedures were performed by two experienced orthopaedists. Theywere returned to our clinic at 4-8 weeks after operation for follow-up orthopaedic and radiographic examinations. The next follow-ups were carried out at 4-6-week intervals, if needed. The implants for internal fracture were removed after clinical and radiological bone healing. All criteria were analyzed by using χ2 test and Fischer's exact test with P < 0.05 and P < 0.01 to evaluate the incidence bone infection in each group of patients. A high percentage of the bacterial isolates was coagulase-negative staphylococci resistent to cephalosporins. the highest sensitivity of all isolates (coagulase-negative Stapylococcus, Staphylococcus aureus, Bacillus spp., Corynebacterium spp., Serratia liquefaciens, Alcaligenes faecalis and Escherichia coli) was observed to ceftriaxone (100 %), as well as to danofloxacin (80.9%) and amoxicillin/clavulanic acid (57.1%). The highest resistant isolates was determined against to penicillin (66.6%) and ampicillin/sulbactam (57.1%). Although we use cephalosporins prophylactically in all patients undergoing orthopaedic surgery in our clinic, the incidence of postoperative infections was very low. Discussion: As the surgical site infection etiology is multi-factorial, the sterilization, preoperative patient preparation and operating theatre environments must be considered as the main sources of this bacterial contamination. Antiseptics used in our practice were theoretically supposed to be effective. Since povidone-iodine and chlorhexidine have a broad spectrum of antimicrobial activity against vegetative bacteria, fungi, viruses, protozoa, and yeasts, they are suitable for removing bacteria from the skin surface at preoperative surgical site. Additionally, povidone-iodine surgical scrub is also used extensively in veterinary practice for the pre-operative preparation of patients and surgeons. Therefore, it is obvious that the use of cephalosporins as preoperative prophylaxis is sufficient in most cases. In the patients at high risk of osteomyelitis development (polytraumatized or immunosuppressed patients, patients receiving prosthetic joint or large metallic implants), or in the patients where the infection is already present, it is important to know hospital-specific pathogens to select adequate complementary antibiotics (in this case we use cephalosporines together with quinolones such as danofloxacin). This emphasizes the need of epidemiologic studies, specific for each clinic.