Antibiotics in Surgery PDF

Antibiotics in surgery Antimicrobials 1.Chemical substances 2.Antibiotics 1. Chemical Eg. Sulpha Bacteriostatic Block the enzyme system of the bacterial cell 2. Antibiotic  they are secreted from organisms to kill other organisms.  They are either bacteriostatic or bactericidal. A...

Antibiotics in surgery Antimicrobials 1.Chemical substances 2.Antibiotics 1. Chemical Eg. Sulpha Bacteriostatic Block the enzyme system of the bacterial cell 2. Antibiotic  they are secreted from organisms to kill other organisms.  They are either bacteriostatic or bactericidal. Action  cell wall synthesis  cell wall function  protein synthesis  DNA of the cell  Antibiotics may be narrow spectrum or broad spectrum Action Bactericidal Bacteriostatic (needs effective body defensive mechanism ) May use - single antibiotic - combination of antibiotics In combination action may be Synergism ( action ) Antagonism ( action ) (bactericidal + bacteriostatic) Bacterial resistance to antibiotic may be  happens when germs like bacteria develop the ability to defeat the drugs designed to kill them.  Common causes: 1. Over prescription of antibiotics. 2. Patients not finishing the entire antibiotic course. 3. Overuse of antibiotics in livestock and fish farming. 4. Poor infection control in health care settings. 5. Poor hygiene and sanitation.  the most common antibiotic-resistant diseases:  methicillin-resistant Staphylococcus aureus (MRSA). Choice of antibiotic: depend on I. Patient: 1. Allergy to antibiotic. 2. Renal and hepatic function. 3. Resistance of the host. 4. Age. 5. In females: pregnancy, lactation, other drugs e.g. oral contraceptive pills. II. Causative organism:  According to culture and sensitivity.  Types of antibiotics Crystalline penicillin ( destroyed by gastric acid ) (injection ) effective against gram positive and gram negative bacteria. MRSA are resistant against penicillin. Oral penicillin ( acid resistant) (Ampicillin ) Cephalosporin's ( 1st , 2nd ,3rd , generations )( duracif , Keflex , cefotax ) Tetracycline ( vibramycin , siqmamycin ) Aminoglycoside (gentamycin, streptomycin)  Types of antibiotics Chloramphenicol: more active against anaerobic organism.  Metronidazole: Excellent anaerobic activity but no effect against aerobic organisms as flagyl.  Clindamycin: very effective against anaerobes, has some gram positive activity.  Route of administration Parental (I.V , IM, sc, ID ) Oral (enteral ) Intracavitary Topical N.B : antibiotic is not a substitutional for a carful aseptic technique Indications of antibiotics 1. In general infections 2. In specific infections 3. With surgery 4. Prophylactic Indications of prophylactic antibiotics Trauma , accidental wounds Prosthesis Ischemia Valvular heart disease Gross contamination Very clean operation ( heart , brain , joint ) Oral surgery Anti-tuberculosis (T.B) 1 st line - streptomycin - PAS (paracetyl salicylic acid) - iso-nictonic hydrazide (INH) 2 nd line - Rifampicin - ethambutol Abuse ( when not indicated ) Masking clinical picture Delay symptoms , signs Antibioma Development of resistant strains Side effects  Specific toxic effects  Hypersensitivity reactions (anaphylaxis ) Urticaria , fever , itching , skin rash , bone marrow depression , leucopenia , agranulocytosis  Vit. B  Secondary infections , fungal  Development of resistant strains  Diarrhea  Abuse  Economic factor Thank you