What is the treatment for a 72-year-old male with a urine culture showing greater than 100,000 Colony-Forming Units (CFU) per milliliter (mL) of carbapenem-resistant Klebsiella pneumoniae and Extended-Spectrum Beta-Lactamase (ESBL)-positive Proteus mirabilis?

From the Guidelines

For a 72-year-old male with a urine culture showing carbapenem-resistant Klebsiella pneumoniae and ESBL-positive Proteus mirabilis, the recommended treatment is a combination of intravenous colistin (loading dose of 9 million units followed by 4.5 million units every 12 hours) plus high-dose meropenem (2 grams every 8 hours as a 3-hour infusion) for 10-14 days, as suggested by the most recent guidelines 1.

This treatment approach is based on the latest recommendations for managing complicated urinary tract infections (cUTIs) due to multidrug-resistant organisms, including carbapenem-resistant Enterobacterales (CRE) and ESBL-producing organisms 1. The use of colistin in combination with meropenem is supported by recent studies, which have shown that this combination can be effective in treating CRE infections, including those caused by Klebsiella pneumoniae 1.

Alternative options, such as ceftazidime-avibactam (2.5 grams every 8 hours) or fosfomycin (3 grams orally every 48 hours for 3 doses), may be considered if the isolates are susceptible, as indicated by antimicrobial susceptibility testing 1. However, the primary concern in this case is the presence of carbapenem-resistant Klebsiella pneumoniae and ESBL-positive Proteus mirabilis, which limits the treatment options.

Some key points to consider in the management of this patient include:

• The need for dose adjustments for renal impairment, as both colistin and meropenem can be nephrotoxic 1.
• The importance of monitoring the patient closely for clinical improvement, potential nephrotoxicity from colistin, and follow-up cultures to ensure eradication of the infection 1.
• The potential need for urological evaluation to rule out structural abnormalities or obstruction, which may be contributing to the development of the complicated UTI 1.
• The importance of maintaining hydration throughout treatment to minimize the risk of nephrotoxicity and ensure optimal drug concentrations in the urine 1.

Overall, the treatment of this patient requires careful consideration of the latest guidelines and evidence-based recommendations, as well as close monitoring and individualized care to ensure the best possible outcome.

From the FDA Drug Label

Colistimethate for Injection, USP has proven clinically effective in treatment of infections due to the following gram-negative organisms: Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa Colistimethate for Injection, USP may be used to initiate therapy in serious infections that are suspected to be due to gram-negative organisms and in the treatment of infections due to susceptible gram-negative pathogenic bacilli

For a 72-year-old male with a urine culture showing greater than 100,000 CFU/mL of carbapenem-resistant Klebsiella pneumoniae and ESBL-positive Proteus mirabilis, the treatment options are limited.

• Colistin 2 may be considered for the treatment of Klebsiella pneumoniae infection, as it has proven clinically effective against this organism.
• However, Colistin 2 is not indicated for infections due to Proteus.
• There is no direct information in the provided drug labels to support the use of Tigecycline 3 for the treatment of carbapenem-resistant Klebsiella pneumoniae or ESBL-positive Proteus mirabilis.

From the Research

Treatment Options for Carbapenem-Resistant Klebsiella pneumoniae and ESBL-Positive Proteus mirabilis

The treatment of a 72-year-old male with a urine culture showing greater than 100,000 CFU/mL of carbapenem-resistant Klebsiella pneumoniae and ESBL-positive Proteus mirabilis requires careful consideration of the available evidence.

• Aminoglycosides: Studies have shown that aminoglycosides, such as amikacin, may be effective in treating carbapenem-resistant Klebsiella pneumoniae 4, 5.
• Combination Therapy: Combination therapy with a carbapenem and an aminoglycoside, such as meropenem and amikacin, may also be effective 5.
• Colistin and Fosfomycin: Other options, such as colistin and fosfomycin, may also be considered, although their effectiveness may vary depending on the specific strain of bacteria 6.
• Newer Antibiotics: Newer antibiotics, such as ceftazidime/avibactam, may also be effective against carbapenem-resistant Klebsiella pneumoniae 7.
• Strain Type: The strain type of the bacteria may also impact treatment outcomes, with some studies suggesting that certain strain types, such as ST258A, may be more resistant to treatment 8.

Considerations for Treatment

When selecting a treatment option, it is essential to consider the following factors:

• Antimicrobial susceptibility testing: Results of antimicrobial susceptibility testing should guide the selection of antibiotics.
• Strain type: The strain type of the bacteria may impact treatment outcomes.
• Combination therapy: Combination therapy may be necessary to achieve optimal outcomes.
• Patient factors: Patient factors, such as renal function and comorbidities, should be considered when selecting a treatment option.

ESBL-Positive Proteus mirabilis

For ESBL-positive Proteus mirabilis, treatment options may include:

• Carbapenems: Carbapenems, such as meropenem, may be effective against ESBL-positive Proteus mirabilis.
• Aminoglycosides: Aminoglycosides, such as amikacin, may also be effective.
• Fosfomycin: Fosfomycin may be another option for treating ESBL-positive Proteus mirabilis 6.