ANTIBIOTICS IN SURGERY

Tuan Ahmad Zulkarnain

Nur-Liyana

Supervisor: Dr. Zalikha

OUTLINE• Introduction

• Antibiotics Classification

• Uses of Antibiotics in Surgery

• Prophylaxis

• Therapeutic

• Take home messages

ANTIBIOTICS

• A substance which has the capacity to kill or inhibit the growth/ spread of microorganism

NORMAL FLORA

ANTIBIOTICS CLASSIFICATION

Principles of Antibiotics in Surgery

• Indication (prophylaxis vs. therapeutic)

• Susceptibility vs. empirical

• Pharmacokinetic

• Pharmacodynamics

• Combination ?

• Cost

• Availability

• Monitoring

• Compliance

Antibiotics Prophylaxis in Surgery

• Use of antibiotic where there is no evidence of infection but expected to be exposed to pathogens that constitutes a major risk of infection.

• Single dose regime, based on the most common organism, which is given at the time of induction to ensure the minimum inhibitory concentration during skin incision – reduces risk of surgical site infection (SSI) and post op infection

• Usually a single dose is sufficient. A second dose may be required in the following situations:

• a. in prolonged operations

• b. when there is contamination during operation

• Giving more than 1 or 2 doses postoperatively is generally not advised. The practice of continuing prophylactic antibiotics until surgical drains have been removed is not recommended.

(NAG 2008)

General Principles of Surgical Prophylaxis

• A single preoperative dose of antibiotic is as effective as full five days course of therapy assuming uncomplicated procedure.

• Prophylactic antibiotics should be administered within 1 hour prior to incision, preferably with induction of anesthesia.

• Prophylactic antibiotics should target anticipated organisms.

• Prophylaxis is generally recommended for clean-contaminated (risk of infection is 6%) and contaminated (risk of infection is 15%) operations

• In clean operation prophylaxis is also indicated under certain conditions i.e. where there is prosthesis implanted, high risk perforation where infection is catastrophic e.g. neurosurgery or cardiac surgery.

Classification of Surgical Wound

Goals of Antibiotic Prophylaxis

• Reduce the incidence of surgical site infection (SSI)

• Minimize the effect on the patient’s normal bacterial flora.

• Minimize adverse side effects of antibiotics.

• Minimize the emergence of antibiotics resistant strains of bacteria.

• Cost effectiveness.

PROCEDURE SUGGESTED ANTIBIOTIC

1. GI surgery2. HBS surgery

IV Cefoperazone 1g PLUS IV Metronidazole 500mg

1. Hernia repair with mesh(includes laparoscopic repair)2. Breast (not recommended for minor excision3.Burns

IV Cloxacillin 1G

Vascular Operation IV Ampicillin/Sulbactam 1.5g

Neurosurgery IV Ceftriaxone 1g AND IV Metronidazole 500mg

Urology IV Amoxicillin / clavulanate 1.2g

GUIDELINES FOR SURGICAL PROPHYLACTIC ANTIBIOTICS

THERAPEUTIC ANTIBIOTICS

Therapeutic

Antibiotics:

PRINCIPLES

C&S

Pharmaco-dynamics

& TDM

Host status

Site of infection

Combination

Prevent resistance

Synergism/ Additive therapy

Multiple pathogens

THERAPEUTIC

ANTIBIOTICS

EmpiricalInitiation of treatment prior to determination of a firm

diagnosis

DefinitiveSpecific to organism isolated in C&S

EMPIRIC THERAPY• When to start ?

• Risk of surgical infection is high - based on the underlying disease process (e.g. perforated appendicitis) [prophylaxis empiric]

• Significant contamination during surgery has occurred (e.g. considerable spillage of colon contents)

• In critically ill patients – potential site of infection has been identified

• Severe sepsis or septic shock

• Short course (3-5 days)

• Stop if the presence of a local site or systemic infection is not revealed

MONOMICROBIAL VS POLYMICROBIAL

• Monomicrobial infections:

• Nosocomial which occurred in postoperative patients, e.g. UTI, pneumonia, catheter-related infection

• Polymicrobial infections:

• culture results less helpful

• Thus, antibiotic regimen should not be modified solely on culture information. Clinical course is more important.

Systemic Inflammatory Response Syndrome (SIRS)

• Empiric antibiotics are not indicated for all patients with SIRS

• Indications for antibiotic therapy include the following:

• Suspected or diagnosed infectious etiology (e.g. UTI, pneumonia, cellulitis)

• Neutropenia or other immunocompromised states

• Asplenia - Due to the potential for overwhelming postsplenectomy infection

HBS:1) Liver

• Enterobacteriaceae, Enterococci, Bacteroides

• Cefobid & Flagyl - penetrate well into abscess cavity

• Ampicillin & Gentamicin & Flagyl

2) GB• E. coli, Klebsiella,

Strep. faecalis• Only certain

antibiotics can be excreted in bile

• Unasyn, Cefobid & Flagyl

• Cholangitis – Imipenem, Tazocin

Stomach & Duodenum:• H. pylori • Clarithromycin &

Flagyl or Amoxycillin

Pancreas:• Enterobacteriacea

e, B. fragilis• Ciprofloxacin/

Flagyl, Carbapenems

Jejunum, Ileum, Large bowel:• Enterobacteriaceae,

Enterococci, Bacteroides

• Ampicillin & Gentamicin & Metronidazole

• Broad spectrum (3rd generation Cephalosporins) & Flagyl

• Abdominal trauma – 3rd generation Cephalosporins, Cefuroxime, Augmentin, Unasyn

• Perforated viscus, Peritonitis - 3rd generation Cephalosporins & Flagyl

• Breast abscess (S. aureus) – Cloxacillin

• Mycotic pseudoaneurysm – Cloxacillin

• Prostethic graft infection - 3rd generation Cephalosporins

• MRSA - Vancomycin

DURATION OF THERAPY

• Duration should be long enough to prevent relapse yet not excessive, as it can increase side effects and resistance

• Factors such as decreasing trend of WBCs and lack of fever guide the length of therapy

• The search for extra abdominal source of infection or a residual /ongoing source of intra abdominal infection should be sought

DURATION OF THERAPY• Penetrating GI trauma without extensive

contamination • 12-24hours

• Perforated/gangrenous appendicitis • 3-5days

• Peritoneal soilage due to perforated viscus with moderate degrees of contamination • 5-7days

• Extensive peritoneal soilage/immunocompromised host• 7-14days

SIDE EFFECTSAntibiotic Side Effects

Penicillins • Allergy (serious anaphylaxis)

Cephalosporins • Allergy

Aminoglycosides • Hearing loss• Vertigo• Renal dysfunction

Carbapenems • Seizures (Imipenem)• Rashes

Macrolides • Prolonged QT interval (Erythromycin)

• Hearing loss• Jaundice

ANTIBIOTIC RESISTANCE• Resistance of a microorganism to an

antimicrobial agent to which it was previously sensitive

• Resistant organisms are able to withstand attack by antimicrobial medicines so that standard treatments become ineffective and infections persist and may spread to others

ANTIBIOTIC RESISTANCEIntrinsic

• Drug target is not present in the bacteria’s metabolic pathways

Acquired

• Mutation

• Transfer of genetic material from resistant to susceptible organisms (plasmids, transposons, bacteriophages)

Main factors contributing to resistance are:

• Excess antibiotic usage

• Incorrect use of broad spectrum agents

• Incorrect dosing

• Non compliance

TAKE HOME MESSAGES

• Prophylactic antibiotic should be given in clean surgery which involves prosthetic implants, in clean-contaminated and contaminated surgeries

• Prophylactic antibiotics should be administered within 1 hour prior to incision

• Therapeutic antibiotic should be started for dirty wound

• Empirical therapy should be altered according to the sensitivity of the culture

• Escalation and de-escalation of antibiotics should be done based on clinical response and aided by culture and sensitivity results

• Therapeutic drug monitoring is done in antibiotics with narrow therapeutic range (Amikacin, Gentamycin, Vancomycin)

• Allergic reactions include anaphylaxis, fever, rashes, nephritis, granulocytopenia & hemolytic anemia are possible side effects of Penicillins and Cephalosporins

• Appropriate choice of antibiotics, dosage, compliance should be ensured to avoid emergence of resistance

THANK YOUReferences:

• National Antibiotic Guideline 2008

• Schwartz’s Principles of Surgery

• Niederman MS. Principles of appropriate antibiotic use

• Medscape

• Enterococcal Resistance – An Overview (YA Marothi, H Agnihotri, D Dubey) Indian Journal of Medical Microbiology, (2005) 23 (4):214-9

• Antibiotics in the treatment of biliary infection (J S Dooley, J M Hamilton-Miller, W Brumfitt, and S Sherlock) Gut. 1984 Sep; 25(9): 988–998.