General Surgery

Infection/Condition and Likely Organism

Suggested Treatment

Comments

Preferred Treatment

Alternative Treatment

Mild to moderate

No antibiotics

Antibiotics should be given for an extra-pancreatic infection, such as cholangitis, catheter-acquired infections, bacteremia, urinary tract infections and pneumonia.

Severe

Possible causative organisms:

Enterobacteriaceae, Enterococci, Staphylococcus aureus, Streptococcus spp., Staphylococcus epidermidis Anaerobes, Candida spp. (rarely)

Piperacillin-tazobactam 4.5gm IV q6-8h

Cefoperazone 1-2gm IV q12h

PLUS

Metronidazole 500mg IV q8h

Antibiotic mainly indicated for infected pancreatic necrosis.

Carbapenem for resistant pathogens ONLY.

Infection/Condition and Likely Organism

Suggested Treatment

Comments

Preferred Treatment

Alternative Treatment

Diverticulitis

(Not undergoing a source control procedure)

Amoxicillin-clavulanate 625mg PO q8h for 5 days

OR

Ampicillin-sulbactam IV 3gm q6h

Non-severe Penicillin allergy:

Cefuroxime 1.5gm IV q8h

PLUS

Metronidazole 500mg IV q8h

Antibiotics considered for patients with following: Fever, elevated WBC, patients who have failed to respond to conservative management.

Diverticulitis

(Severe infection/life-threatening infection)

Piperacillin-tazobactam 4.5gm IV q6-8h for 7 days

OR

Meropenem 1 gm IV q8h

**Severe Penicillin allergy: Ciprofloxacin 400mg IV q12h

PLUS

Metronidazole 500mg IV q8h

Infection/Condition and Likely Organism

Suggested Treatment

Comments

Preferred Treatment

Alternative Treatment

Common organism:

Staphylococcus aureus

Flucloxacillin 500mg IV q6h

OR

Cloxacillin 500mg IV q6h

OR

Cefazolin 1-2gm IV q8h

Amoxicillin-clavulanate 625mg PO q8h

OR

Ampicillin-sulbactam 750mg PO q12h

Penicillin allergy:

Clindamycin 600mg IV/ PO q8h

Aspiration/Drainage is required for abscess.

For lactating mastitis: Consider sending breast milk for C&S if not responding after 48h of initial antibiotic therapy or recurring mastitis.

Duration: 10-14 days but shorter course (5 to 7 days) can be used if the response to therapy is rapid and complete.

Infection/Condition and Likely Organism

Suggested Treatment

Comments

Preferred Treatment

Alternative Treatment

Common organisms:

Enterobacteriaceae

Enterococci

Bacteroides

Ceftriaxone 1 gm IV q12h

OR

Amoxicillin-clavulanate 1.2gm IV q8h

Ampicillin-sulbactam 1.5gm IV q6-8h

OR

Cefoperazone 1-2 gm IV q12h

PLUS

Metronidazole 500mg IV q8h

 OR

Ornidazole 500mg IV q12h

Acute appendicitis without evidence of perforation, abscess, or local peritonitis; undergoing emergency appendectomy, treatment should be discontinued within 24 hours.

For patients with various forms of appendicitis not undergoing a source control procedure, change to early oral therapy.

Duration: 5-7 Days.

Infection/Condition and Likely Organism

Suggested Treatment

Comments

Preferred Treatment

Alternative Treatment

Perforated Appendix / Appendicular Lump

Ceftriaxone 1g IV q12h

OR

Amoxicillin-clavulanate 1.2gm IV q8h

Ampicillin-sulbactam 1.5-3gm IV q6-8h

PLUS

Metronidazole 500mg IV q8h

OR

Piperacillin-tazobactam 4.5 gm IV q8h

Duration: 5-7 days.

Infection/Condition and Likely Organism

Suggested Treatment

Comments

Preferred Treatment

Alternative Treatment

Perforated Viscus Peritonitis

Ampicillin-sulbactam 1.5-3gm IV q6-8h

PLUS

Metronidazole 500mg IV q8h

OR

Ornidazole 500mg IV q12h

Amoxicillin-clavulanate 1.2gm IV q8h

OR

Piperacillin-tazobactam 4.5 gm IV q8h

Duration: 5-7 days (If adequate source control, no delay in surgical intervention and patient has rapid clinical recovery).

Infection/Condition and Likely Organism

Suggested Treatment

Comments

Preferred Treatment

Alternative Treatment

Stab Wound

Suspected bowel or solid organ injury

Common organisms:

Gram negative enteric aerobes and anaerobes

Amoxicillin-clavulanate 1.2gm IV q8h

Cefuroxime 1.5gm IV q8h

PLUS

Metronidazole 500mg IV q8h

*Stab wound without bowel injury or solid organ injury – Ceftriaxone 1g IV q12h.

Duration: 5-7 days (If adequate source control, no delay in surgical intervention and patient has rapid clinical recovery).

*Abdominal trauma with suspected bowel injury – treat as perforated viscus peritonitis.

Severe / Infected wound:

Ceftriaxone 1gm IV q12h

PLUS

Metronidazole 500mg IV q8h (if anaerobic contamination suspected)

OR

Piperacillin-tazobactam 4.5gm IV q6-8h

Severe / Infected wound: Ciprofloxacin 400mg IV q12h

PLUS

Clindamycin 450-600mg IV q8h

Infection/Condition and Likely Organism

Suggested Treatment

Comments

Preferred Treatment

Alternative Treatment

Perianal abscess

Ceftriaxone 1 gm IV q12h

OR

Ciprofloxacin 500mg IV q12h

PLUS

Metronidazole 500mg IV q8h

Piperacillin-tazobactam 4.5gm IV q6-8h

Drainage is required.

Duration: 5-7 days (If adequate source control, no delay in surgical intervention and patient has rapid clinical recovery).

Routine antibiotic is not recommended in otherwise healthy patients.

Infection/Condition and Likely Organism

Suggested Treatment

Comments

Preferred Treatment

Alternative Treatment

Mycotic aneurysm (Initial Treatment)

Vascular prosthesis infection

Common organisms:

Streptococcus pneumoniae

Staphylococcus aureus (30%)

Salmonella spp. (50%)

Ceftriaxone 2gm IV q24h

Piperacillin-tazobactam

4.5gm IV q6-8h

Duration: At least six weeks (IV then oral based on clinical response and cultures).

Consider adding Vancomycin if suspecting MRSA/CoNS or Vascular prosthesis infection.

* C-reactive protein (CRP) monitoring upon follow-up.

*Step down therapy:

Amoxicillin-clavulanate 625mg PO q8h

OR

Ciprofloxacin 250mg PO q12h

Ischemic limb ulcers with infection

Ampicillin-sulbactam 1.5- 3gm IV q6-8h for 7 days*

OR

Cefazolin 1-2 gm IV q12h

Amoxicillin-clavulanate 1.2 gm IV q8h for 7 days*

Duration: Depends on the extent of the infection. (longer if bone involved) *Continue until C&S report available.

Infection/Condition and Likely Organism

Suggested Treatment

Comments

Preferred Treatment

Alternative Treatment

Animal bite

Common organisms:

Staphylococcus aureus

Streptococcus

Gram negative bacilli

Anaerobes

Pasteurella (50% dog bites

and 75% cat bites)

Eikenella corrodens

Pseudomonas spp.

Amoxicillin-clavulanate 625mg PO q8h

(IV if severe infection)

Doxycycline 100mg PO q12h

PLUS

Clindamycin 300mg PO q6h

Prophylactic duration: 3-5 days.

Associated crush injury In the hands or proximity to a joint

Associated edema.

If wound is infected: 10 days or longer is recommended.

Note: Vaccination against rabies and/or TT as required.

If severe/life threatening:

Ampicillin-sulbactam 1.5-3gm IV q6-8h

If severe/life threatening:

Piperacillin-tazobactam 4.5gm IV q6-8h

Human bite

Common organisms:

Staphylococcus aureus

Anaerobes

Eikenella corrodens

Streptococcus (esp. viridans)

Amoxicillin-clavulanate 625mg PO q8h  (IV if severe infection)

Penicillin allergy:

Clindamycin 300mg PO q6h

PLUS

Ciprofloxacin 500-750mg PO q12h

OR

Trimethoprim-sulfamethoxazole 160/800mg PO q12h

Infection/Condition and Likely Organism

Suggested Treatment

Comments

Preferred Treatment

Alternative Treatment

Antibiotics should not be used unless there are local or systemic symptoms of infection. Local treatment including surgical debridement is important. Antibiotic selection should be based on the most recent culture and sensitivity report.

Mild infections:

Local infection involving skin and subcutaneous tissues

Erythema, less than 2 cm around the ulcer

No systemic signs of infection

Amoxicillin-clavulanate 625mg PO q8h

OR

Ampicillin-sulbactam 375-750mg PO q12h

Cephalexin 500mg PO q6H

PLUS

Metronidazole 400mg PO q8h

Duration 5-7 days.

Moderate infection:

a.  Deep tissue infection

b.  Erythema more than 2 cm around ulcer

c.  No SIRS

Ampicillin-sulbactam 3gm IV q6-8h

OR

Amoxicillin-clavulanate 1.2g IV q12h

PLUS

Metronidazole 500mg IV q8h

Cefazolin 2gm IV q8hrly

PLUS

Clindamycin 600mg IV q8h

Penicillin allergy:

Ciprofloxacin 400mg IV q8-12h

PLUS

Clindamycin 600mg IV q8h

Duration: 7-14 days Modify according to clinical response.

If Pseudomonas is suspected:

Piperacillin-tazobactam 4.5gm IV q6-8h

Severe Infections:

• All of the above 2 or  more SIRS
• History of previous antibiotics exposure
• Recurrent admission Risk of Pseudomonas infection
• Immunocompromised

Piperacillin-tazobactam

4.5gm IV q6-8h

Cefepime 2gm IV q8h

PLUS

Metronidazole 500mg IV q8h

URGENT Surgical debridement.

Duration: 7-14 days (up to 4-6 weeks).

Shorter duration can be considered if the osteomyelitis is fully resected.

No surrounding soft tissue infection: 5 days. Evidence of soft tissue infection: 10-14 days.

Infection/Condition and Likely Organism

Suggested Treatment

Comments

Preferred Treatment

Alternative Treatment

Type 1

Polymicrobial infection

Primarily occurs in patients who are immunocompromised or have certain chronic disease such as diabetes

Ampicillin-sulbactam 3 gm IV q6-8h

PLUS*

Clindamycin 600-900mg IV q8h

OR

Metronidazole 500mg IV q8h

Piperacillin-tazobactam 4.5gm IV q6-8h

OR

Cefepime 2 gm IV q8h

PLUS

Clindamycin 600-900mg IV q8h

OR

Metronidazole 500mg IV q8h

Source Control

*Clindamycin:

Only necessary if risk of group A streptococcus/ presence of gas crepitus.

Type 2

Monomicrobial infection Group A streptococcus (most common)

Benzylpenicillin 2-4MU IV q4h PLUS*

Clindamycin 600-900mg IV q8h

*Clindamycin:

Only necessary if risk of group A streptococcus/ presence of gas crepitus.

Duration: 7-14 days.

Vibrio vulnificus

Aeromonas hydrophila

Consider in water-related injuries and patients with liver cirrhosis and ingestion of raw oysters

Ceftriaxone 1gm IV q12h

PLUS

Doxycycline 100mg PO q12h

Ciprofloxacin 400mg IV q8h

*Clindamycin:

Only necessary if risk of group A streptococcus/ presence of gas crepitus.

Duration: 7-14 days.

Fournier’s Gangrene

Common organisms:

Escherichia coli

Klebsiella spp.

Proteus spp.

Enterococcus spp.

Pseudomonas spp. Anaerobes

Piperacillin-tazobactam 4.5gm IV q6-8h

PLUS

Metronidazole 500mg IV q8h

Imipenem 1g IV q6-8h

PLUS

Clindamycin 600-900mg IV q8h

Consider Vancomycin 30mg/kg/day IV in 2 divided doses if MRSA suspected

Aggressive debridement is necessary to remove all necrotic tissue.

Infection/Condition and Likely Organism

Suggested Treatment

Comments

Preferred Treatment

Alternative Treatment

Common organisms:

Clostridium spp.

Gram negative organism

Benzylpenicillin 4MU IV q4h

PLUS

Clindamycin 600-900mg IV q6h

PLUS*

*Gentamicin 5mg/kg IV q24h

Piperacillin-tazobactam 4.5gm IV q6-8h

PLUS

Clindamycin 600-900mg IV q6h

Duration: 10-28 days Source control is necessary.

*Gentamicin: If Gram negative infection suspected.

Infection/Condition and Likely Organism

Suggested Treatment

Comments

Preferred Treatment

Alternative Treatment

Suppurative wound infections, surgical or traumatic

Antibiotics if surrounding cellulitis and/or systemic symptoms

Cloxacillin 500mg PO/IV q6h

PLUS*

Gentamicin 5mg/kg IV q24h

OR

Cefuroxime 1.5gm IV q8h

Flucloxacillin 500mg PO q6h

Topical antibiotics - NOT recommended

Duration : 5-7 days Patient’s tetanus immunization status should be assessed in all cases.

*Gentamicin if gram negative organisms suspected or isolated.