Abdominopelvic Infections | Infectious Diseases Management Program at UCSF

Abdominal Infections

Patient Population:

Adult

See Pelvic Inflammatory disease for that syndrome

Diagnosis	Common Pathogens	Drug(s) of First Choice	Alternative Drug(s)	Comments	Expected Duration
Community-acquired secondary peritonitis Mild-moderate intra-abdominal abscess (community acquired)	E. coli Klebsiella B. fragilis Streptococci spp	Ceftriaxone PLUS Metronidazole	For severe beta-lactam allergy: Vancomycin PLUS Aztreonam PLUS Metronidazole		Stop antibiotics 4 days after source control achieved If source control is not obtained, consultation with ID recommended
Healthcare-associated secondary peritonitis Mild-Moderate intra-abdominal abscess (including post-op pelvic abscesses)	Community pathogens PLUS S. aureus Enterococci P. aeruginosa	Piperacillin/tazobactam OR Cefepime PLUS Metronidazole	For severe PCN allergy: Vancomycin PLUS Aztreonam PLUS Metronidazole	Fungal coverage rarely needed empirically but consider in high-risk patients: critically ill with upper GI source, recurrent bowel perforation, heavy colonization, surgically-treated pancreatitis	Stop antibiotics 4 days after source control achieved If source control is not obtained, consultation with ID recommended
Severe peritonitis with major peritoneal soilage, large or multiple abscesses, or hemodynamically unstable	Similar to healthcare associated peritonitis	Vancomycin PLUS one of Piperacillin/ tazobactam OR Meropenem*	For severe PCN allergy: Vancomycin PLUS Aztreonam PLUS Metronidazole	*For hemodynamically unstable health-care associated infection, consider meropenem Fungal coverage rarely needed empirically but consider in high-risk patients: critically ill with upper GI source, recurrent bowel perforation, heavy colonization, surgically-treated pancreatitis	ID consultation is recommended
Diverticulitis For severe infection, refer to severe secondary peritonitis, above	E. coli Klebsiella B. fragilis Streptococci spp	Management without antibiotics can be considered in patients with uncomplicated disease (no signs of severe infection, no evidence of fistula or abscess, not immunosuppressed) Inpatient: Ceftriaxone PLUS Metronidazole Outpatient: Amoxicillin/clavulanic acid 875/125 mg po TID OR Ciprofloxacin PLUS Metronidazole	For severe beta-lactam allergy: Inpatient: Vancomycin PLUS Aztreonam PLUS Metronidazole Outpatient: Ciprofloxacin PLUS Metronidazole		10 days (can step down to oral therapy to complete course)
SBP (Spontaneous Bacterial Peritonitis)	E. coli Klebsiella spp. Streptococci. spp.	Ceftriaxone	For severe PCN allergy: Vancomycin PLUS Aztreonam	In patients who received previous courses of antibiotics consider expanding coverage If known MDR GNR and/or VRE colonization/infection within 90 days, expand coverage to include these pathogens	5 days
Liver abscess	E. Coli Klebsiella Strep milleri group (S. anginosus, constellatus, intermedius)	Ceftriaxone PLUS Metronidazole	For severe beta-lactam allergy: Vancomycin PLUS Aztreonam PLUS Metronidazole	Consider Vancomycin if patient is hemodynamically unstable Consider amoebic liver abscess if appropriate travel history	ID consult recommended

Diagnosis

Common Pathogens

Drug(s) of First Choice

Alternative Drug(s)

Comments

Expected Duration

Community-acquired secondary peritonitis

Mild-moderate intra-abdominal abscess (community acquired)

E. coli

Klebsiella

B. fragilis

Streptococci spp

Ceftriaxone PLUS

Metronidazole

For severe beta-lactam allergy:

Vancomycin PLUS

Aztreonam PLUS

Metronidazole

Stop antibiotics 4 days after source control achieved

If source control is not obtained, consultation with ID recommended

Healthcare-associated secondary peritonitis

Mild-Moderate intra-abdominal abscess (including post-op pelvic abscesses)

Community pathogens

PLUS

S. aureus

Enterococci

P. aeruginosa

Piperacillin/tazobactam

Cefepime PLUS

Metronidazole

For severe PCN allergy:

Vancomycin PLUS

Aztreonam PLUS

Metronidazole

Fungal coverage rarely needed empirically but consider in high-risk patients: critically ill with upper GI source, recurrent bowel perforation, heavy colonization, surgically-treated pancreatitis

Stop antibiotics 4 days after source control achieved

If source control is not obtained, consultation with ID recommended

Severe peritonitis with major peritoneal soilage, large or multiple abscesses, or hemodynamically unstable

Similar to healthcare associated peritonitis

PLUS one of

For severe PCN allergy:

Vancomycin PLUS

Aztreonam PLUS

Metronidazole

*For hemodynamically unstable health-care associated infection, consider meropenem

Fungal coverage rarely needed empirically but consider in high-risk patients: critically ill with upper GI source, recurrent bowel perforation, heavy colonization, surgically-treated pancreatitis

ID consultation is recommended

Diverticulitis

For severe infection, refer to severe secondary peritonitis, above

E. coli

Klebsiella

B. fragilis

Streptococci spp

Management without antibiotics can be considered in patients with uncomplicated disease (no signs of severe infection, no evidence of fistula or abscess, not immunosuppressed)

Inpatient: Ceftriaxone PLUS

Metronidazole

Outpatient: Amoxicillin/clavulanic acid 875/125 mg po TID

Ciprofloxacin PLUS

Metronidazole

For severe beta-lactam allergy:

Inpatient: Vancomycin PLUS

Aztreonam PLUS

Metronidazole

Outpatient:

Ciprofloxacin PLUS

Metronidazole

10 days (can step down to oral therapy to complete course)

SBP (Spontaneous Bacterial Peritonitis)

E. coli

Klebsiella spp.

Streptococci. spp.

Ceftriaxone

For severe PCN allergy:

Vancomycin PLUS

Aztreonam

In patients who received previous courses of antibiotics consider expanding coverage

If known MDR GNR and/or VRE colonization/infection within 90 days, expand coverage to include these pathogens

5 days

Liver abscess

E. Coli

Klebsiella

Strep milleri group (S. anginosus, constellatus, intermedius)

Ceftriaxone PLUS

Metronidazole

For severe beta-lactam allergy:

Vancomycin PLUS

Aztreonam PLUS

Metronidazole

Consider Vancomycin if patient is hemodynamically unstable

Consider amoebic liver abscess if appropriate travel history

ID consult recommended

Clinical Infectious Diseases, Volume 50, Issue 2, 15 January 2010, Pages 133–164, https://doi.org/10.1086/649554

Abdominopelvic Infections

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Pelvic Inflammatory Disease

Patient Population:

Adult

Empiric treatment recommendations for adult patients with Pelvic Inflammatory Disease (PID) with or without Tubo-Ovarian Abscess (TOA).

Note: Post-operative pelvic abscess should be treated as a post-operative abdominal abscess (see IDMP empiric dosing recommendations).

Diagnosis	Common Pathogens	Drug(s) of First Choice^a	Alternative Drug(s)^a	Comments	Expected Duration^b
Pelvic Inflammatory Disease (mild-moderate, outpatient)	Anaerobes Enteric GNRs G. vaginalis H. influenzae Streptococcus agalactiae	Ceftriaxone 500 mg IM x1* PLUS Doxycycline PLUS Metronidazole For >150 kg with documented gonococcal infection, use ceftriaxone 1 g. If Inpatient with IV access, may use 1 g IV regardless of body weight to avoid painful IM injection.	For severe penicillin allergy: Clindamycin PLUS Gentamicin IV 5 mg/kg once daily^c If improvement after 24-48h, step-down: Doxycycline PLUS Metronidazole	Step down to PO if improving after 24-28h on parenteral regimen	14 days
Pelvic Inflammatory Disease (severe, hospitalized) +/- Tubo-Ovarian Abscess (TOA)	Anaerobes Enteric GNRs G. vaginalis H. influenzae Streptococcus agalactiae	Ceftriaxone PLUS Doxycycline PLUS Metronidazole If improvement after 24-48h, step-down: *Doxycycline* PLUS *Metronidazole*	For severe penicillin allergy: Clindamycin PLUS Gentamicin IV 5 mg/kg once daily^c If improvement after 24-48h, step-down: *Doxycycline* PLUS Metronidazole	Step down to PO if improving after 24-28h on parenteral regimen If TOA, surgical drainage may be necessary	14 days

Diagnosis

Common Pathogens

Drug(s) of First Choice^a

Alternative Drug(s)^a

Comments

Expected Duration^b

Pelvic Inflammatory Disease (mild-moderate, outpatient)

Anaerobes

Enteric GNRs

G. vaginalis

H. influenzae

Streptococcus agalactiae

Ceftriaxone 500 mg IM x1*

PLUS

Doxycycline

PLUS

Metronidazole

*For >150 kg with documented gonococcal infection, use ceftriaxone 1 g.

*If Inpatient with IV access, may use 1 g IV regardless of body weight to avoid painful IM injection.

For severe penicillin allergy:

Clindamycin

PLUS

Gentamicin IV 5 mg/kg once daily^c

If improvement after 24-48h, step-down:

Doxycycline

PLUS

Metronidazole

Step down to PO if improving after 24-28h on parenteral regimen

14 days

Pelvic Inflammatory Disease (severe, hospitalized)

+/- Tubo-Ovarian Abscess (TOA)

Anaerobes

Enteric GNRs

G. vaginalis

H. influenzae

Streptococcus agalactiae

Ceftriaxone

PLUS

Doxycycline

PLUS

Metronidazole

If improvement after 24-48h, step-down:

Doxycycline

PLUS

Metronidazole

For severe penicillin allergy:

Clindamycin

PLUS

Gentamicin IV 5 mg/kg once daily^c

If improvement after 24-48h, step-down:

Doxycycline

PLUS

Metronidazole

Step down to PO if improving after 24-28h on parenteral regimen

If TOA, surgical drainage may be necessary

14 days

^a Dosing assumes normal renal function, adjustments for renal impairment may apply.

^b Total duration should include effective IV days of therapy.

^c If normal renal function, start with gentamicin 5 mg/kg once daily and then adjust per Urban-Craig nomogram (high dose, extended interval dosing). If renal impairment, dose gentamicin to target peak 6-8 and trough <1 (traditional dosing).

*Note that drug shortages may dictate supplies and preferred regimens may adjust as needed.

Workowski KA, Bachmann LH, Chan PA, et al. Sexually Transmitted Infections Treatment Guidelines, 2021. 2021;70(4).

Abdominopelvic Infections

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Healthcare-associated Intra-abdominal Infections

Patient Population:

Pediatric

Condition	Major Pathogens	First-choice Therapy	Alternative Therapy	Comments
Intra-abdominal infection, healthcare-associated, age > 1 month, and excluding infants with necrotizing enterocolitis Includes patients with any of the following risk factors for resistant or opportunistic organisms:  Hospitalized for at least 48 hours before onset of signs/symptoms of intra-abdominal infection  Significant medical comorbidities and/or healthcare exposure prior to onset of infection Infection developed post-operatively (signs/symptoms were not present prior to surgery) Refer to BCH SF Necrotizing Enterocolitis Pathway for NEC treatment recommendations If the above criteria do not apply and the patient’s signs/symptoms started prior to hospitalization (community-onset), refer to Appendicitis Clinical Algorithm (BCH OAK and BCH SF shared algorithm)	Enteric gram- negative bacteria Pseudomonas aeruginosa, other resistant gram-negative bacteria Anaerobes	Piperacillin-tazobactam (Zosyn) 100 mg piperacillin/kg/dose (max 4000 mg piperacillin/dose) IV q6h	Penicillin allergy with lower risk for allergic reaction: Cefepime 50 mg/kg/dose (max 2000 mg/dose) IV q8h  AND  Metronidazole 10 mg/kg/dose (max 500mg/dose) IV q8h  ------------------------- Penicillin or cephalosporin allergy with higher risk for allergic reaction: Ciprofloxacin 15 mg/kg/dose (max 400 mg/dose)  IV q12h  AND  Metronidazole 10 mg/kg/dose (max 500 mg/dose) IV q8h	Consider ID consult especially if additional patient risk factors for antibiotic resistant infection, immunocompromised patient, severe manifestations or inadequate response to initial empiric therapy If a pathogen is isolated from a normally sterile site, therapy should be modified to treat the identified pathogen, but coverage of enteric gram-negatives and anaerobes should usually be maintained because intra-abdominal infections are usually polymicrobial. Consult ID for further recommendations if needed.  Duration: If adequate source control, 4 days If source control procedure not performed, but favorable response to therapy, 5-7 days guided by clinical parameters (fever, leukocytosis, adequacy of gastrointestinal function)

Condition

Major Pathogens

First-choice Therapy

Alternative Therapy

Comments

Intra-abdominal infection, healthcare-associated, age > 1 month, and excluding infants with necrotizing enterocolitis

Includes patients with any of the following risk factors for resistant or opportunistic organisms: 

Hospitalized for at least 48 hours before onset of signs/symptoms of intra-abdominal infection 

Significant medical comorbidities and/or healthcare exposure prior to onset of infection

Infection developed post-operatively (signs/symptoms were not present prior to surgery)

Refer to BCH SF Necrotizing Enterocolitis Pathway for NEC treatment recommendations

If the above criteria do not apply and the patient’s signs/symptoms started prior to hospitalization (community-onset), refer to Appendicitis Clinical Algorithm (BCH OAK and BCH SF shared algorithm)

Enteric gram- negative bacteria

Pseudomonas aeruginosa, other resistant gram-negative bacteria

Anaerobes

Piperacillin-tazobactam (Zosyn) 100 mg piperacillin/kg/dose (max 4000 mg piperacillin/dose) IV q6h 

Penicillin allergy with lower risk for allergic reaction:

Cefepime
50 mg/kg/dose (max 2000 mg/dose) IV q8h 

AND 

Metronidazole
10 mg/kg/dose (max 500mg/dose) IV q8h 

-------------------------

Penicillin or cephalosporin allergy with higher risk for allergic reaction:

Ciprofloxacin
15 mg/kg/dose (max 400 mg/dose)  IV q12h 

AND 

Metronidazole
10 mg/kg/dose (max 500 mg/dose) IV q8h 

Consider ID consult especially if additional patient risk factors for antibiotic resistant infection, immunocompromised patient, severe manifestations or inadequate response to initial empiric therapy

If a pathogen is isolated from a normally sterile site, therapy should be modified to treat the identified pathogen, but coverage of enteric gram-negatives and anaerobes should usually be maintained because intra-abdominal infections are usually polymicrobial. Consult ID for further recommendations if needed. 

Duration: If adequate source control, 4 days

If source control procedure not performed, but favorable response to therapy, 5-7 days guided by clinical parameters (fever, leukocytosis, adequacy of gastrointestinal function) 

Reference

Mazuski JE, et al. The Surgical Infection Society revised guidelines on the management of intra-abdominal infection. Surgical Infections 2017;18:1-76.

Abdominopelvic Infections

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