Urinary Tract Infection Organism-Specific Therapy 

Updated: Feb 10, 2015
  • Author: Nirav Patel, MD; Chief Editor: Thomas E Herchline, MD  more...
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Specific Organisms and Therapeutic Regimens

Organism-specific therapy for urinary tract infection (UTI) should be based on in vitro susceptibility data from a patient-specific isolate, as wide geographic variability exists. [1, 2, 3, 4, 5] The narrowest-spectrum drug that retains appropriate susceptibility is recommended, even if multiple agents including the initial empiric choice are found to have susceptibility.

In addition, fluoroquinolones, such as ciprofloxacin and levofloxacin, while highly effective for uncomplicated infection, have added risks, including the propensity to select for subsequent infection with more resistant organisms, and thus should be reserved for other uses. [6]

Uncomplicated urinary tract infections

Escherichia coli (trimethoprim/sulfamethoxazole sensitive) [7, 8, 9, 6, 10]

  • Trimethoprim/sulfamethoxazole 160 mg/800 mg (1 DS tablet) PO BID for 3 days or
  • Trimethoprim 100 mg PO BID for 3 days or
  • Nitrofurantoin macrocrystals 50-100 mg PO QID for 5 days or
  • Nitrofurantoin sustained-release 100 mg PO BID for 5 days or
  • Ciprofloxacin 250 mg PO BID or extended-release 500 mg PO daily for 3 days or
  • Levofloxacin 250 mg PO daily for 3 days

Escherichia coli (trimethoprim/sulfamethoxazole resistant) [11, 12, 13]

  • Ciprofloxacin 250 mg PO BID or extended-release 500 mg PO daily for 3 days or
  • Levofloxacin 250 mg PO q24h for 3 days or
  • Nitrofurantoin macrocrystals 50-100 mg PO QID for 7 days or
  • Nitrofurantoin sustained-release 100 mg PO BID for 7 days

Staphylococcus saprophyticus

  • Cephalexin 500 mg PO QID for 7 days or
  • Amoxicillin-clavulanate 875-125 mg PO BID for 7 days or
  • Ciprofloxacin 250 mg PO BID or extended-release 500 mg PO daily for 3 days or
  • Levofloxacin 250 mg PO daily for 3 days

Klebsiella species [11]

  • Trimethoprim/sulfamethoxazole 160 mg/800 mg (1 DS tablet) PO BID for 3 days or
  • Ciprofloxacin 250 mg PO BID or extended-release 500 mg PO daily for 3 days or
  • Levofloxacin 250 mg PO daily for 3 days or
  • Nitrofurantoin macrocrystals 50-100 mg PO QID for 7 days or
  • Nitrofurantoin sustained-release 100 mg PO BID for 7 days

Proteus species

  • Trimethoprim/sulfamethoxazole 160 mg/800 mg (1 DS tablet) PO BID for 3 days or
  • Ciprofloxacin 250 mg PO BID or extended-release 500 mg PO daily for 3 days

Enterobacteriaceae species

  • Trimethoprim/sulfamethoxazole 160 mg/800 mg (1 DS tablet) PO BID for 3 days or
  • Nitrofurantoin macrocrystals 50-100 mg PO QID for 7 days or
  • Nitrofurantoin sustained-release 100 mg PO BID for 7 days or
  • Ciprofloxacin 250 mg PO BID or extended-release 500 mg PO daily for 3 days or
  • Levofloxacin 250 mg PO daily for 3 days

Pseudomonas aeruginosa

  • Ciprofloxacin 500-750 mg PO BID for 3 days
  • Discuss alternatives with an infectious disease specialist

Candida species

  • Fluconazole 200-mg loading dose followed by 100 mg PO daily for at least 4 days
  • Discuss alternatives with an infectious disease specialist

Complicated urinary tract infections

In vitro susceptibility is essential to guide therapy, as high-level drug resistance is more frequently encountered in the patient with complicated UTI. [14] Early consideration of consultation with an infectious diseases specialist is prudent to ensure optimal therapy.

The duration of therapy can be reduced in patients who have prompt resolution of symptoms and who are not severely ill; 7 days of therapy could be considered in patients who respond rapidly, while a longer duration (10-14 days) may be considered in patients who have a delayed response. [14] A 3-day course of therapy can be considered in women aged 65 years or younger without upper urinary tract symptoms. [14]

The narrowest-spectrum drug that retains appropriate susceptibility is recommended, even if multiple agents, including the initial empiric choice, are found to have susceptibility. In addition, fluoroquinolones, such as ciprofloxacin and levofloxacin, have added risks, including the propensity to select for subsequent infection with more resistant organisms, and thus should be reserved for other uses. [6]

Escherichia coli (trimethoprim/sulfamethoxazole sensitive) [7, 8, 9, 6]

  • Trimethoprim/sulfamethoxazole 160 mg/800 mg (1 DS tablet) PO BID for 7-14 days or
  • Piperacillin-tazobactam 3.375 g IV q6h for 7-14 days or
  • Cefazolin 2 g IV q8h for 7-14 days or
  • Ceftriaxone 2 g IV q24h for 7-14 days or
  • Ertapenem 1 g IV q24h for 7-14 days or
  • Imipenem-cilastatin 500 mg IV q6h for 7-14 days or
  • Meropenem 1 g IV q8h for 7-14 days or
  • Ciprofloxacin 500 mg PO BID or 400 mg IV q12h or extended-release 1 g PO daily for 7-14 days or
  • Levofloxacin 750 mg PO or IV daily for 5-14 days

Escherichia coli (trimethoprim/sulfamethoxazole resistant)

  • Piperacillin-tazobactam 3.375 g IV q6h for 7-14 days or
  • Cefazolin 2 g IV q8h for 7-14 days or
  • Ceftriaxone 2 g IV q24h for 7-14 days or
  • Ertapenem 1 g IV q24h for 7-14 days or
  • Imipenem-cilastatin 500 mg IV q6h for 7-14 days or
  • Meropenem 1 g IV q8h for 7-14 days or
  • Ciprofloxacin 500 mg PO BID or 400 mg IV q12h or extended-release 1 g PO daily for 7-14 days or
  • Levofloxacin 750 mg PO or IV daily for 7-14 days

Staphylococcus saprophyticus

  • Amoxicillin-clavulanate 875-125 mg PO BID for 7-14 days or
  • Ampicillin-sulbactam 3 g IV q6h for 7-14 days or
  • Cephalexin 500 mg PO QID for 7-14 days or
  • Cefazolin 2 g IV q8h for 7-14 days or
  • Ceftriaxone 2 g IV q24h for 7-14 days or
  • Ciprofloxacin 500 mg PO BID or 400 mg IV q12h or extended-release 1 g PO daily for 7-14 days or
  • Levofloxacin 750 mg PO or IV daily for 7-14 days

Klebsiella species

  • Trimethoprim/sulfamethoxazole 160 mg/800 mg (1 DS tablet) PO BID for 7-14 days or
  • Piperacillin-tazobactam 3.375 g IV q6h for 7-14 days or
  • Cefazolin 2 g IV q8h for 7-14 days or
  • Ceftriaxone 2 g IV q24h for 7-14 days or
  • Ertapenem 1 g IV q24h for 7-14 days or
  • Imipenem-cilastatin 500 mg IV q6h for 7-14 days or
  • Meropenem 1 g IV q8h for 7-14 days or
  • Ciprofloxacin 500 mg PO BID or 400 mg IV q12h or extended-release 1 g PO daily for 7-14 days or
  • Levofloxacin 750 mg PO or IV daily for 7-14 days

Proteus species

  • Trimethoprim/sulfamethoxazole 160 mg/800 mg (1 DS tablet) PO BID for 7-14 days or
  • Cefazolin 2 g IV q8h for 7-14 days or
  • Ceftriaxone 2 g IV q24h for 7-14 days or
  • Ertapenem 1 g IV q24h for 7-14 days or
  • Imipenem-cilastatin 500 mg IV q6h for 7-14 days or
  • Meropenem 1 g IV q8h for 7-14 days or
  • Ciprofloxacin 500 mg PO BID or 400 mg IV q12h or extended-release 1 g PO daily for 7-14 days or
  • Levofloxacin 750 mg PO or IV daily for 7-14 days

Enterobacteriaceae species

  • Trimethoprim/sulfamethoxazole 160 mg/800 mg (1 DS tablet) PO BID for 7-14 days or
  • Piperacillin-tazobactam 3.375 g IV q6h for 7-14 days or
  • Cefazolin 2 g IV q8h for 7-14 days or
  • Ceftriaxone 2 g IV q24h for 7-14 days or
  • Ertapenem 1 g IV q24h for 7-14 days or
  • Imipenem-cilastatin 500 mg IV q6h for 7-14 days or
  • Meropenem 1 g IV q8h for 7-14 days or
  • Ciprofloxacin 500 mg PO BID or 400 mg IV q12h or extended-release 1 g PO daily for 7-14 days or
  • Levofloxacin 750 mg PO or IV daily for 7-14 days

Pseudomonas aeruginosa

  • Piperacillin-tazobactam 3.375 g IV q6h for 7-14 days or
  • Ceftazidime 2 g IV q6-8h for 7-14 days or
  • Cefepime 2 g IV q8h for 7-14 days or
  • Imipenem-cilastatin 500 mg IV q6h for 7-14 days or
  • Meropenem 1 g IV q8h for 7-14 days or
  • Ciprofloxacin 500-750 mg PO BID or 400 mg IV q12h or extended-release 1 g PO daily for 7-14 days or
  • Levofloxacin 750 mg PO or IV daily for 7-14 days

Enterococcus faecalis

  • Amoxicillin 500 mg PO TID for 7-14 days
  • Discuss alternatives with an infectious disease specialist