Abdominal infections





This chapter will review the guidelines by the Infectious Diseases Society of America (IDSA).


Note: Empiric antibiotics should be tailored based on local pathogen prevalence and antibiotic susceptibility, pathogen-specific risk factors, and previous pathogens and antibiotic exposure. Once final culture and susceptibility results become available, empiric antibiotics should be optimized according to the identified pathogen(s) and susceptibility.


Complicated intra-abdominal infection


Definition


IDSA and Surgical Infection Society define complicated intra-abdominal infection as infection extending beyond the hollow viscus of origin into the peritoneal space that is associated with abscess formation or peritonitis.


Risk factors for source control failure





  • Delay in treatment (>24 h)



  • High severity of illness (Acute Physiology and Chronic Health Evaluation II score ≥15)



  • Age >70 years



  • Medical comorbidity



  • Degree of organ dysfunction



  • Low albumin



  • Poor nutritional status



  • Degree of peritoneal involvement or diffuse peritonitis



  • Inability to achieve adequate debridement or drainage



  • Malignancy



Pathogens in order of prevalence





  • Escherichia coli



  • Bacteroides species



  • Streptococcus species



  • Clostridium species



  • Peptostreptococcus species, Eubacterium species



  • Klebsiella species, Pseudomonas aeruginosa



  • Prevotella species, Enterococcus faecalis



Treatment





  • Antibiotic regimen ( Table 10.1 )



    Table 10.1

    Empiric Antibiotic Therapy for Complicated Intra-Abdominal Infection

    Adapted from Solomkin JS, Mazuski JE, Bradley JS, et al. Diagnosis and management of complicated intra-abdominal infection in adults and children: guidelines by the Surgical Infection Society and the Infectious Diseases Society of America. Clin Infect Dis . 2010;50(12): 133–164.








































    TYPE OF INFECTION ANTIBIOTIC REGIMEN
    Community-Acquired Extra-Biliary Intra-Abdominal Infection



    • Mild-moderate severity




    • Cefoxitin



    • Ertapenem



    • Moxifloxacin



    • Tigecycline



    • Ticarcillin-clavulanic acid (unavailable in U.S.)



    • Cefazolin + metronidazole



    • Cefuroxime + metronidazole



    • Ceftriaxone + metronidazole



    • Cefotaxime + metronidazole



    • Ciprofloxacin a + metronidazole



    • Levofloxacin a + metronidazole

    High severity


    • Imipenem-cilastatin



    • Meropenem



    • Doripenem



    • Piperacillin-tazobactam



    • Cefepime + metronidazole



    • Ceftazidime + metronidazole



    • Ciprofloxacin a + metronidazole



    • Levofloxacin a + metronidazole

    Biliary Intra-Abdominal Infection
    Community-acquired acute cholecystitis of mild to moderate severity


    • Cefazolin



    • Cefuroxime



    • Ceftriaxone

    Community-acquired acute cholecystitis of high severity or acute cholangitis following bilio-enteric anastomosis


    • Imipenem-cilastatin



    • Meropenem



    • Doripenem



    • Piperacillin-tazobactam



    • Cefepime + metronidazole



    • Ciprofloxacin a + metronidazole



    • Levofloxacin a + metronidazole

    Health care–associated biliary infection


    • Vancomycin plus one of the following:



    • Imipenem-cilastatin



    • Meropenem



    • Doripenem




    • Piperacillin-tazobactam



    • Cefepime + metronidazole



    • Ciprofloxacin a + metronidazole



    • Levofloxacin a + metronidazole

    Health Care–Associated Intra-Abdominal Infection
    <20% resistant Pseudomonas aeruginosa , ESBL-producing Enterobacteriaceae , Acinetobacter , or other MDR GNB


    • Imipenem-cilastatin



    • Meropenem



    • Doripenem



    • Piperacillin-tazobactam



    • Cefepime + metronidazole



    • Ceftazidime + metronidazole

    ESBL-producing Enterobacteriaceae , Pseudomonas aeruginosa >20% resistant to ceftazidime


    • Imipenem-cilastatin



    • Meropenem



    • Doripenem



    • Piperacillin-tazobactam



    • Aminoglycoside

    MRSA Vancomycin

    ESBL , Extended-spectrum β-lactamase; GNB , Gram-negative bacilli; MDR , Multidrug resistant; MRSA , Methicillin-resistant Staphylococcus aureus

    a Recommend reviewing local population susceptibility reports given increasing resistance of Escherichia coli to fluoroquinolones




  • Antibiotic dosing ( Table 10.2 )



    Table 10.2

    Antibiotic Dosing for Complicated Intra-Abdominal Infection

    Data from Solomkin JS, Mazuski JE, Bradley JS, et al. Diagnosis and management of complicated intra-abdominal infection in adults and children: guidelines by the Surgical Infection Society and the Infectious Diseases Society of America. Clin Infect Dis . 2010;50(12):133–164.


















































































































































    ANTIBIOTIC STANDARD DOSE (IV) RENAL DOSING COMMENTS
    Β-Lactam/β-Lactamase Inhibitor Combination
    Piperacillin-tazobactam


    • Non-PSA: 3.375 g q6h



    • PSA: 4.5 g q6h




    • Non-PSA:



    • CrCl 20–40: 2.25 g q6h



    • CrCl <20: 2.25 g q8h



    • HD: 2.25 g q12h a



    • PSA:



    • CrCl 20–40: 3.375 g q6h



    • CrCl <20: 2.25 g q6h



    • HD: 2.25 g q8h a




    • Off-label extended infusion:



    • 3.375–4.5 g ×1 over 30 min, followed 4 h later by 4 h infusion q8h

    Carbapenems (Cross-Sensitivity With PCN Allergy)
    Doripenem


    • 500 mg q8h




    • CrCl 30–50: 250 mg q8h



    • CrCl 11–29: 250 mg q12h



    • HD: 250 mg q24h a ; If PSA, 500 mg q12h ×1 then 500 mg 24 h a




    • Similar spectrum of activity as meropenem except more potent in vitro activity against PSA than meropenem

    Ertapenem


    • 1 g q24h




    • CrCl ≤30 and HD: 500 mg daily




    • Compared to imipenem or meropenem, less active against PSA, Acinetobacter , enterococci , and PCN-resistant pneumococci

    Imipenem-cilastatin


    • 500 mg q6h or 1 g q8h




    • CrCl 60–89: 500 mg q6h



    • CrCl 30–59: 500 mg q8h



    • CrCl 15–29 and HD: 500 mg q12h a



    • CrCl <15 without HD: avoid use




    • Consider decreasing dose in patients <70 kg to prevent seizures

    Meropenem


    • 1 g q8h




    • CrCl 26–50: same dose q12h



    • CrCl 10–25: half dose q12h



    • CrCl <10: half dose q24h



    • HD: 500 mg q24h a




    • Similar spectrum of activity as imipenem; slightly lower risk of seizures than imipenem

    Cephalosporins (10% Cross-Sensitivity With PCN Allergy)
    Cefazolin


    • 1–2 g q8h




    • CrCl 11–34: 50% dose q12h



    • CrCl ≤10 and HD: 50% dose q24h a

    Cefepime


    • 2 g q8–12h




    • CrCl 30–60: 2 g q12–24h



    • CrCl <30: 1–2 g q24h



    • HD: 0.5–1 g q24h a




    • Risk of seizures in renal insufficiency

    Cefotaxime


    • 2 g q8h




    • CrCl <20: 50% dose q8h



    • HD: 1–2 g q24h a

    Cefoxitin


    • 2 g q6h




    • CrCl 30–50: 2 g q8–12h



    • CrCl 10–29: 2 g q12–24h



    • CrCl 5–9: 2 g ×1 then 1 g q12–24h



    • CrCl <5 and HD: 2 g ×1 then 1 g q24–48h a

    Ceftazidime


    • 2 g q8h




    • CrCl 31–50: 2 g q12h



    • CrCl 16–30: 2 g q24h



    • CrCl ≤15 and HD: 1 g q24h a

    Possible cross-sensitivity between aztreonam and ceftazidime (<5%); avoid aztreonam if history of life-threatening reaction or anaphylaxis to ceftazidime. Other cephalosporins do not have the same risk as ceftazidime
    Ceftriaxone


    • 2 g q24h

    Cefuroxime (Zinacef)


    • 1.5 g q8h




    • CrCl 10–20: 1.5 g q12h



    • CrCl <10 and HD: 1.5 g q24h a

    Ceftazidime 2 g-avibactam 0.5 g (Avycaz 2.5 g)


    • 2.5 g q8h




    • CrCl 31–50: 1.25 g q8h



    • CrCl 16–30: 0.94 g q12h



    • CrCl 6–15: 0.94 g q24h



    • CrCl ≤5 and HD: 0.94 g q48h a




    • Reserve for MDR PSA, and ESBL- and KPC-producing Enterobacteriaceae.



    • Combine with metronidazole

    Ceftolozane 1 g-tazobactam 0.5 g (Zerbaxa 1.5 g)


    • 1.5 g q8h




    • CrCl 30–50: 750 mg q8h



    • CrCl 15–29: 375 mg q8h



    • CrCl <15: not studied



    • HD: 750 mg ×1 then 150 mg q8h a




    • Reserve for MDR PSA and ESBL-producing Enterobacteriaceae.



    • Combine with metronidazole

    Glycylcycline
    Tigecycline


    • 100 mg ×1 then 50 mg q12h




    • Increase in all-cause mortality observed in meta-analysis of Phase 3 and 4 clinical trials where greatest differences seen with ventilator-associated pneumonia

    Fluoroquinolones



    • Ciprofloxacin




    • 400 mg q12h




    • CrCl 5–29 and HD: 400 mg q24h a




    • ADR: tendonitis/tendon rupture, CNS effects, peripheral neuropathy, hepatotoxicity, crystalluria, photosensitivity, QT prolongation. CI: myasthenia gravis, children due to musculoskeletal toxicity

    Levofloxacin


    • 750 mg q24h




    • CrCl 20–49: 750 mg q48h



    • CrCl 10–19: 750 mg ×1, then 500 mg q48h



    • HD: 750 mg ×1, then 500 mg q48h a

    Moxifloxacin


    • 400 mg q24h




    Nitroimidazole
    Metronidazole


    • 500 mg q8h




    • Give post HD on HD days

    Aminoglycosides
    Gentamicin or tobramycin


    • 5–7 mg/kg q24h b




    • CrCl 20–60: 5–7 mg/kg q36–48 h b



    • CrCl <20 and HD: 1–2.5 mg/kg LD, then based on level a , c




    • Consult pharmacist for dosing. Goal for once daily dosing: refer to Hartford nomogram d . Use adjusted BW for obese

    Amikacin


    • 15–20 mg/kg q24h b




    • CrCl 20–60: 15–20 mg/kg q36–48h b



    • CrCl <20 and HD: 5 mg/kg LD then based on level a , c

    Monobactam
    Aztreonam


    • 1–2 g q6–8h




    • CrCl 10–30: 0.5–1 g q6–8h



    • CrCl <10: 250–500 mg q6–8h



    • HD: 1–2 g LD, then 250–500 mg q6–8h a




    • Possible cross-sensitivity between aztreonam and ceftazidime (<5%); see comment on ceftazidime

    Glycopeptide
    Vancomycin


    • 15–20 mg/kg q8–12h




    • CrCl 15–50: 750–1500 mg q24h



    • Max: 2 g/dose



    • CrCl <15: 750–1500 mg based on level



    • HD: 500–1000 mg based on level a




    • Consult pharmacist for dosing



    • Goal trough: 10–15 mcg/mL (15–20 mcg/mL if visceral abscesses)



    • Use actual BW for obese

    Notes:


    • Surgical management is critical in most intra-abdominal infections



    • 4–5 days is the recommended duration who have adequate source control; longer duration is appropriate if inadequate or uncertain source control




    • Empiric antifungal may be considered for upper gastrointestinal perforations, recurrent bowel perforations, surgically treated pancreatitis, heavy colonization with Candida species, or presence of yeast on intra-abdominal cultures




      • Candida albicans : Fluconazole IV 800 mg ×1 then 400 mg daily



      • Fluconazole-resistant Candida species:




        • Anidulafungin IV 200 mg ×1 then 100 mg daily



        • Caspofungin IV 70 mg ×1 then 50 mg daily



        • Micafungin IV 100 mg daily





    • Antienterococcal therapy: consider in postoperative infection, those who have previously received cephalosporins or other antimicrobial agents selecting for Enterococcus species, immunocompromised patients, and those with valvular heart disease or prosthetic intravascular materials



    • Anti-MRSA therapy: consider in patients with MRSA or MDRO risk factors (advanced age, comorbid medical conditions, previous hospitalization/surgery, recent antibiotic agents)

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Feb 28, 2021 | Posted by in EMERGENCY MEDICINE | Comments Off on Abdominal infections
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