Antibiotic Therapy in Surgical Practice

Chairpersons:

Prof. U. Bhattacharjee

Dr. D.B.Chowdhury

Speaker:

Parvej Sultan

History1862 Pasteur1865 Lister1866 Semmelweiss1928 Alexandar FlemingToday ? Postantibiotic era <2 %

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

Classes of Antibiotics

Target Sites

Staphylococcus

Streptococcus

Gram negatives

Anaerobes

• 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:

Antibiotics in surgical practice are only

an adjunct to treating surgical infection

Thank You