Antimicrobial Prophylaxis

GENERAL PRINCIPLES

1.ANTI MICROBIALS CANNOT ELIMINATE ALL MICRO ORGANISMS IN THE HOST AND CANNOT PREVENT ALL TYPES OF INFECTION. HENCE PROPHYLAXIS SHOULD BE DIRECTED AGAINST A SPECIFIC PATHOGEN OR USED TO PREVENT INFECTION AT A SPECIFIC SITE

2.SHORTER THE DURATION OF PROPHYLAXIS THE LARGER THE RANGE OF PATHOGENS AFFECTED. FOR PREVENTION OF ALL INFECTIONS IN LEUCOPOENIAS BROAD SPECTRUM ANTI MICROBIALS à SHORT TERM LONG TERM USE--à RESISTANCE GROUP “A” STREP àLONG TERM USE.

3. PROPHYLAXIS MORE EFFECTIVE AGAINST PATHOGENS LESS LIKELY TO DEVELOP RESISTANCE Eg. Penicillin for Grp.”A” strepàeffective Not for gonococcus

4. DRUGS FOR THERAPY MAY NOT BE GOOD FOR PROPHYLAXIS

Eg.PENICILLIN IN MENINGOCOCCAL MENINGITIS NOT EFFECTIVE FOR PROPHYLAXIS

5. PROPHYLACTIC DRUGS SHOULD ONLY BE USED WHEN EFFICACY HAS BEEN DOCUMENTED COST, TOXICITY, SUPERINFECTION DEVELOPMENT OF RESISTANCE

SURGICAL PROPHYLAXIS

n A M MUST BE EFFFECTIVE AGAINST MAJORITY OF ORGANISMS CAUSING POST.OP. INFECTIONS

n START THERAPY 1-2HOURS BEFORE AND STOP 12-48 HOURS AFTER OP.

n A SINGLE PRE OP.DOSE GIVES MAXIMAL BENEFIT

n A M ACTIVITY MUST BE PRESENT IN SURGICAL WOUND BEFORE CLOSURE

n DRUGS

n CEFAZOLIN -àDRUG OF CHOICE First Generation >cephalosporin 0.5GM -2GM I.V.

n CEFEPIME 4^TH GENERATION CEPHALOSPORIN MORE RESISTANCE TO HYDROLYSIS BY BETA LACTAMASE

Eg. ENTEROBACTER THAT MAY INACTIVATE 3^RD GENERATION CEPH.

n DRUG COMBINATIONS

n INDICATIONS

n VERY ILL PATIENTS WITH INFECTIONS OF UNKNOWN ORIGIN Eg SEPTICAEMIA ANTI STAPH (NAFCILLIN-CLOXACILLIN0 WITH Gm –ve BACILLI (GENTAMICIN TOBRAMYCIN AMIKACIN) IMMUNOCOMPROMISED.

n DRUG COMBINATIONS MIXED INFECTIONS PERITONITIS

ANAEROBES– metronidazole, Gm +ve Bacteria- clindamycin COLIFORMS --aminoglycosides

PREVENT RESISTANCE Eg. T.B. ISONIAZID,ETHAMBUTOL,RIFAMPIN.

ENHANCE EFFECT OF SINGLE DRUG Eg. SULPHONAMIDE WITH TRIMETHOPRIM

PENICILLIN WITH AMINOGLYSOIDE--à ENTEROCOCCUS FAECALIS