Chapter 3 Antibiotics can be used for prevention and for therapy. Animals that should receive preventive antibiotic administration are: The choice of prophylactic antibiotic and protocol remains controversial. A wide variety of microorganisms is found in the flora of the mouth and saliva. Antibiotic prophylaxis requires a drug with antimicrobial activity against Gram-positive and Gram-negative aerobes and anaerobes. The timing of administration of antibiotics is critical. It is generally accepted that antibiotics should be administered within 2 h of the surgery and not continued for more than 4 h after the procedure (Peterson 1994; Callender 1999). In addition, antibiotics must be given at a high enough dose to reach a tissue level four times higher than the minimal inhibitory concentration of the causative organisms. A number of studies have shown that ampicillin, amoxicillin–clavulanic acid, certain cephalosporins and clindamycin meet the above requirements in dogs, cats and humans (Harvey et al. 1995a,b; Johnson et al. 1997; Callender 1999; Mueller et al. 1999). The causative agent should be identified and the antibiotic sensitivity determined.: In the oral cavity, the organisms involved have been well defined and are known to include a mixed flora of aerobic and anaerobic, Gram-positive and Gram-negative bacteria (Peterson 1994). Empirical antibiotic treatment based on previous susceptibility studies is, therefore, acceptable. Amoxicillin–clavulanic acid and clindamycin, and to a lesser extent cephalosporins, provide broad antibacterial activity against oral infections in dogs and cats (Harvey et al. 1995a,b). Culture is indicated for infection not responding to the initial treatment, recurrent infection, postoperative wound infection and osteomyelitis. The antibiotic with the narrowest antibacterial spectrum should be used.: This will minimize the risk of development of resistant bacteria (Peterson 1994). Combinations of antibiotics are discouraged.: The exception to this rule is the combination of amoxicillin or cephalosporins with metronidazole in severe mixed infections in which anaerobes are believed to play a major role. A bactericidal antibiotic is preferable to a bacteriostatic agent.: A bactericidal antibiotic (amoxicillin, cephalosporins and metronidazole) is preferred over a bacteriostatic antibiotic (clindamycin), mainly because there is less reliance on host inflammatory and immune reactions. Other considerations include the toxicity of the antibiotic and the patient’s history of previous allergic reactions to a particular antibiotic. The antibiotic of choice must be administered at the proper dose and correct time interval.: Refer to a current compendium of data sheets for veterinary products for correct dosing and time interval. A 7-day course of antibiotics is generally recommended. Osteomyelitis generally requires a longer period of treatment (Rosin et al. 1993). Suboptimal dosing and/or pulse therapy is not recommended.
Antibiotics and antiseptics
Antibiotics
Preventive use of antibiotics
Therapeutic use of antibiotics
Principles for prudent use of therapeutic antibiotics
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