Patient description: The patient is a 60 year old man complaining of frequent headaches, generalized bone pain and difficulty chewing that started 6 years ago and is worsening. Examination shows bilateral swellings around the molars. The swellings have increased since his last examination. Several extraoral lesions are detected in the head and face. The swellings are non-tender and attached to the underlying bone. Further evaluation shows increased uptake of radioactive substance as well as an increase in urinary pyridinoline. His serum alkaline phosphatase is 300 IU/L (the normal range is 44- 147 IU/L). His family history is only significant for hypertension in his mother and DM type 2 in his father. The diagnosis of Paget's Disease of Bone was confirmed and Bisphosphonate will be started as first-line therapy.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Surgical Site Infections Venous Thromboembolism Subjects greater than 18 years of age scheduled for surgical procedure considered to have a high risk for a surgical site infection (SSI) such as 1) secondary repair of a ventral hernia, 2) open bariatric surgery, 3) open abdominal colorectal surgery, 4) trauma surgery, 5) burn surgery or 6) sternotomy. 2. Patients must have one of the following risk factors for surgical site infection: emergency surgery, obesity, diabetes mellitus, cancer surgery, be immune-compromised or otherwise be at an increased risk for SSI. 3. Only adults will participate as research subjects 4. This study will involve both males and females 5. Patients in ASA (American Society of Anesthesiology) class I or II or III or IV will be included. Treatment assignment will be stratified with respect to ASA classification. 6. Abdominal wound classifications: Clean-Contaminated, Contaminated, or Dirty are eligible to participate. Treatment assignment will be stratified with respect wound classification. Similarly, trauma and burn patients will be classified. 7. Patient must be able to understand the same written and spoken language as either the surgeon or nurse who provides informed-consent information to the patient. 8. Patients must be appropriately screened for the proposed surgery  Procedures involving only simple ostomy closures 2. Known allergy to cefazolin or metronidazole or an antibiotic preferred and routinely used by the surgeon 3. Persons less than 18 years old 4. Emergency operation as designated by the surgeon will be included only with the appropriate approval by the institutional IRB at an individual research site 5. Pregnant or breast-feeding women 6. A known bleeding/hemorrhagic/thrombotic disorder is exclusionary unless there is a written clearance chart-note or clearance letter from a primary care physician or hematologist 7. Significant psychiatric problems which might impair ability to give truly informed consent or which may impair follow-up communication with the surgeon and staff 8. Clinically significant cardiac arrhythmias are exclusionary unless there is a written clearance chart-note or clearance letter from a cardiologist 9. Heart/liver/kidney disease, neuropsychiatric disease classifying patient as ≥ ASA V 10. Major concomitant infections such as pneumonia or sepsis 11. In non-emergency surgery, pre-existing active bacterial skin infection at the time of the surgical incision; however, pre-existing bacterial infections are not exclusionary in burn or trauma patients. 12. Foreign material in the incision that cannot be removed 13. Recent systemic antimicrobial therapy 14. Clinically significant renal impairment or a creatinine clearance < 30 mL/min. Vulnerable Subjects are excluded 1. Pregnant women 2. Nursing home residents, or other institutionalized persons are not fully alert, not cognizant or and not able to give informed consent are not eligible to participate as a research subject 3. Children < 18 years of age