From the Guidelines
From an antibiotic stewardship perspective, it would be best to switch from ceftriaxone to ampicillin for this elderly patient with a Proteus UTI, as ampicillin is a narrower-spectrum antibiotic to which the Proteus is susceptible. Since the culture results show the Proteus is susceptible to ampicillin, this would be the preferred choice over broader-spectrum antibiotics like ceftriaxone. The dosage of ampicillin IV could be 1-2g every 6 hours, with the duration typically being 7-10 days for complicated UTIs in elderly patients 1. Once the patient shows clinical improvement, consider transitioning to oral amoxicillin to complete the course. This de-escalation strategy helps reduce the risk of developing antimicrobial resistance, decreases the potential for C. difficile infection, and minimizes disruption to the patient's normal gut flora.
Some key points to consider in the management of this patient include:
- Ensuring the patient is adequately hydrated, as this can help in the recovery from the UTI and also reduce the risk of kidney damage from the antibiotics.
- Monitoring renal function, as both the infection and antibiotics can impact kidney function in elderly patients.
- Reassessing the patient's clinical status regularly to confirm improvement.
- Considering the removal of any urinary catheter if present, as this can be a source of persistent infection.
It's also important to note that while Keflex (cefalexin) is another option to which the Proteus is susceptible, ampicillin is generally preferred due to its narrower spectrum of activity compared to ceftriaxone, and its effectiveness against Proteus species 1. Ceftriaxone, being a third-generation cephalosporin with broader coverage, should be reserved for situations where narrower options aren't available or effective.
From the Research
Antibiotic Stewardship Perspective
From an antibiotic stewardship perspective, the goal is to use the most appropriate antibiotic with the narrowest spectrum of activity to treat an infection, while minimizing the risk of adverse effects and promoting antimicrobial stewardship.
- The patient has a Proteus UTI susceptible to ampicillin and Keflex (cephalexin) 2.
- Ceftriaxone, a third-generation cephalosporin, is currently being used to treat the patient, but it has a broader spectrum of activity and may increase the risk of health care facility-onset Clostridioides difficile infection (HOCDI) 3.
- Switching from ceftriaxone to a narrower spectrum antibiotic like ampicillin may be a more appropriate choice, as it is effective against Proteus species and has a lower risk of promoting antibiotic resistance and HOCDI 3, 2.
- However, it's essential to consider the patient's individual needs and the local antimicrobial susceptibility patterns when making antibiotic therapy decisions 3, 4.
Considerations for Antibiotic Choice
When choosing an antibiotic, it's crucial to consider the following factors:
- The susceptibility of the infecting organism to the antibiotic 5, 2.
- The risk of adverse effects, such as HOCDI 3.
- The potential for promoting antibiotic resistance 3, 2.
- The patient's individual needs and medical history 4.
Local Susceptibility Patterns
Local antimicrobial susceptibility patterns should be taken into account when selecting an antibiotic.
- A study found that cefazolin, a first-generation cephalosporin, exhibited high susceptibility for uropathogens commonly implicated in cases of uncomplicated UTI 3.
- Another study demonstrated that cephalexin, a first-generation cephalosporin, was effective in treating UTIs, including those caused by Proteus species 4.