Principles of prevention of infection Yaser Baroud

Principles of prophylaxis of wound infection Prophylaxis-if effective- reduces: Morbidity Cost

On the other hand: Prophylactic antibiotics may alter host flora Spread of antibiotic resistant microraganisms in to the community Antibiotic my not significantly decrease the incidence of infection Infection control !!!! Cost Toxicity

Principles of prophylaxis

Principle 1: Procedure Should Have Significant Risk of Infection Infection rates of 10% or more are usually considered unacceptable, and the prophylactic use of antibiotics must be strongly considered for such infection-prone procedures.

Principle 2: Choose Correct Antibiotic  The antibiotic should be effective against the organisms most likely to cause infection in the oral cavity.  The antibiotic chosen should be a narrow spectrum antibiotic.  The antibiotic should be the least toxic antibiotic available for the patient.  The drug selected should be a bactericidal antibiotic. !!!!

The antibiotic of choice for prophylaxis before oral surgery is penicillin or amoxicillin. If the patient is allergic to penicillins, use clindamycin or azithromycin.

Principle 3: Antibiotic Plasma Level Must Be High When antibiotics are used prophylactically, the antibiotic level in the plasma must be higher than when antibiotics are used therapeutically. The dose should be at least two times the usual therapeutic dose. If the surgery is prolonged, interim doses at half the normal dose interval should be used For penicillin or amoxicillin, this is 2 g; for clindamycin, 600 mg; and for azithromycin, 500 mg.

Principle 4: Time Antibiotic Administration Correctly The antibiotic must be given 2 hours or less before the surgery begins. For the oral route, this is usually 1 hour; with the intravenous route, a much shorter preoperative dosing interval is possible. Antibiotic administration that occurs after surgery is greatly decreased in its efficacy or has no effect at all on preventing infection.

Principle 5: Use Shortest Antibiotic Exposure That Is Effective For the antibiotic prophylaxis to be effective, the antibiotic must be given before the surgery begins, and adequate plasma levels must be maintained during the surgical procedure. Once the surgical procedure is completed, continued antibiotic administration produces little, if any, benefit.

((Considerable amounts of animal and human clinical data demonstrate that the prophylactic use of antibiotics is necessary only for the time of surgery; after closure of the wounds and formation of the blood clots, migration of bacteria into the wound and underlying tissues occurs at such a low level that additional antibiotics are not necessary.)) !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

Principles of prophylaxis against metastatic infection Metastatic infection: is defined as infection that occurs at a location physically separate from the portal of entry of the bacteria. Infective endocarditis Factors necessary for metastatic infection:  Distant susceptable site  Hematogenous bacterial seeding  Impaired local defenses (Biofilm)

Prophylaxis against infectious endocarditis Bacteremias have been shown to cause IE. Viridans group streptococci are part of the normal oral flora and have been commonly found in IE. Antibiotic prophylaxis has been shown to prevent experimental endocarditis caused by S. viridans in animals. The risk of significant adverse reaction to the antibiotic is low in an individual patient, and the morbidity and mortality of IE are high.

Recommended conditions for prophylaxis AHA 2007 Prosthetic cardiac valve Previous infective endocarditis Congenital heart disease (CHD)*  Unrepaired cyanotic CHD, including palliative shunts and conduits  Completely repaired congenital heart defect with prosthetic material or device, whether placed by surgery or by catheter intervention, during the first 6 months after the procedure.  Repaired CHD with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device (which inhibit endothelialization) Cardiac transplant recipients who have cardiac valvulopathy

Dental Procedures for Which Endocarditis Prophylaxis Is Recommended All dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa.

Dental Procedures in Which Prophylaxis Is Not Recommended Restorative dentistry Routine local anesthetic injection Intracanal endodontic therapy and placement of rubber dams Suture removal Placement of removable appliances Making of impressions Taking of oral radiographs Fluoride treatments Orthodontic appliance adjustment Shedding of primary teeth

Other conditions  Coronary artery bypass graft  Stents (angioplasty)  Ventriculoatrial shunt  Arteriovenous shunt  Vena cava filter I&D ???

Prophylaxis Against Total Joint Replacement Infection Result in severe morbidity because the implant is usually lost when infections occur. Bacteremias from oral procedures are not likely to cause prosthetic joint infections. Still a Debatable issue