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Antibiotic Therapy in Surgical Practice
Chairpersons:
Prof. U. Bhattacharjee
Dr. D.B.Chowdhury
Speaker:
Parvej Sultan
Classification of Surgical woundsCategory Criteria Infection
Rate(%)Clean No hollow viscus entered;
No breaks in aseptic technique
1-3
Clean-contaminated
Hollow viscus entered but con-trolled; Minor breaks in aseptic technique
5-8
Contaminated
Uncontrolled spillage from viscus; Open traumatic wound
20-25
Dirty/ infected
Untreated,uncontrolled spillage from viscus;
Pus in operative wound
30-40
Before using an antibiotic ask the following
• Is it for treatment or prophylaxis?• What is the likely pathogen
(spectrum)?• What is the site AB are required to
reach?• Route of administration?• Resistance? • Any Allergies?• Is the patient
Immunocompromised?• Toxicity
Gram negatives
• All have a Beta lactam ring as a basic structure
Penicillins Benzyl Penicillin……..Staph/StrepsFlucloxcacillin…………StaphCo-amoxiclav………… Staph/StrepPiperacillin…………… Psuedomonas
Cephalosporins10% Cross sensitivity in patients with penicillin allergy4 generations with Increased G-ve & decreased G+ve in fourth generation.
Carbapenenms Truly broad spectrum ( Gm negative, positive and anaerobes) May provoke seizures May promote highly resistant organisms
Beta lactams
• Active against Staph.aureus and aerobic Gm-ve• Narrow theraputic ratio ( easily toxic)• Monitor renal function and oto-toxicity• Examples:
• Gentamicin• Tobramycin• Amikacin
Aminoglycosides
• Macrolidess e.g. erythromycin, clarithromycin • An alternative in penicillin sensitivity• New generations have improved bioavailability,
better oral absorption and fewer GI side effects.• Quinolones e.g. Ciprofloxacin
• Good tissue penetration• Gram negative activity• Attains good levels on oral intake.
Macrolides & Quinolones
Prophylaxis
1. When anatomical barriers are breached leading to contamination: faeces, bile..etc.
2. When the consequence and risks are unacceptably high
3. In traumatic wounds4. In immunocompromised
The Use of Antibiotics
Therapeutic1. Empirical therapy
– The likely organism & antibiotic susceptibility
– Avoid using a single agent– Avoid using agents with inadequate cover– Avoid AB with serious side effects.
2. Definitive therapy
The Use of Antibiotics
1. Route Intravenous if:
• Patient is seriously ill with inconsistent intestinal absorption or inability to oral medication.
• IV ensures rapid adequate serum levels.• Be aware of therapeutic window.
Oral step down if : • Oral intake is tolerated,• Good absorption, • No unexplained tachycardia, • No need for high tissue concentrations• suitable oral prep. available
Drug administration
• Treatment failure:• Wrong AB/ Wrong dosing• Other causes of infection• Fungal superinfection• Inappropriate administration • Persistent source of infection
• Appropriate narrow spectrum of coverage.• Safety.• Monotherapy• Administration within 1 hour prior to
incision.
Principles of Antibiotics Prophylaxis
Repeat dose of prophylactic antibiotic
Prolonged operationsExcessive blood lossUnexpected contamination occursRepeated every 3-4 hours
Antimicrobial Prophylaxis for surgeryNature of Operation
Routine antibiotic
Penicillin or Cephalosporin allergy
General surgery/endocrine
Cefazolin Clindamycin
Hepatobiliary Cefazolin Gentamicin and Metronidazole
Cholecystectomy (High risk only)
Cefazolin Gentamicin
Appendicectomy
2nd gen. Cephalosporin
Metronidazole plus Gentamicin
Cardiovascular and Thoracic
Cefazolin/ Cefuroxime
Vancomycin
Genitourinary Cefazolin Ciprofloxacin
Colorectal Cefazolin plus Metronidazole
Gentamicin plus clindamycin
Orthopedic/Neurosurgical
Cefazolin Vancomycin
Factors Influencing Antibiotic Choice
Activity against known/ suspected pathogens
Disease believed responsibleAntimicrobial resistance patternsPatient-specific factorsInstitutional guidelines/restrictions
Antibacterial Agents for Empirical UseAntipseudomonal Piperacillin-Tazobactum, Cefepime, Ceftazidime
Gram-positive Glycopeptide( Vancomycin, Televancin) Oxizolidinone( Linezolid )
Gram-negative Third-generation Cephalosporins( not Ceftriaxone) Monobactum, Polymixins(Colistin, polymixin B)
Antianaerobic Metronidazole
Anti-MRSA Vancomycin, Linezolid, Tigecycline,Telavancin
Important Pathogens for critically Ill patients
Vancomycin -resistant Enterococci Daptomycin, Linezolid, Quinupristin-dalfopristin, Tigecycline
MRSA Linezolid, Vancomycin, Q-D,
Pseudomonas aeruginosa Meropenem, Doripenem, Imipenem-cilastin
Multidrug-Resistant Enterobactericeae including Klebsiella species Carbapenems, Tigecyclin
Antibiotic Toxicities
Beta-Lactum allergy Most common toxicity Incidence 7 to 40/1000 treatment course Cross reactivity between Penicillin, Cephalosporin and carbapenemRed Man Syndrome With rapid Vancomycin infusion Tingling and flushing of head, neck or thorax
Nephrotoxicity Amynoglycosides, Vancomycin PolymixinOtotoxicity Amynoglycosides Vancomycin
Antibiotic Toxicities
Antibiotics requiring dosage reduction for Hepatic and Renal insufficiency:
HepaticCefoperazoneClindamycinRifampicinIsoniazidLinezolidErythromycinTigecycline
RenalAminoglycosidesVancomycinFluoroquinolones Cephalosporins(most)Carbapenem Penicillins
Antibiotics requiring dosage reduction for Hepatic and Renal insufficiency: