What antibiotic should be used to treat a patient with Klebsiella (Klebs)-positive urosepsis, hyperchloremic metabolic acidosis, and a penicillin allergy?

From the Guidelines

For a patient with Klebsiella-positive urosepsis, hyperchloremic metabolic acidosis, and a penicillin allergy, I strongly recommend using ceftazidime/avibactam as the first-line treatment option, given its strong recommendation and moderate certainty of evidence 1. This recommendation is based on the latest guidelines for the diagnosis and management of infections caused by multidrug-resistant bacteria, which suggest that novel β-lactam agents such as ceftazidime/avibactam should be the first-line treatment options for patients with infections caused by KPC-producing carbapenem-resistant Enterobacterales (CRE) 1. Some key points to consider when using ceftazidime/avibactam include:

• Its efficacy in treating KPC-producing CRE infections, with a higher clinical cure rate and lower mortality compared to traditional antibiotic regimens 1
• Its safety profile, with a lower risk of nephrotoxicity compared to colistin 1
• The importance of considering local epidemiology and the emergence of ceftazidime/avibactam resistance in KPC-producing isolates 1 Alternatively, meropenem/vaborbactam may also be considered, especially in cases where the site of infection is the lung, given its high intrapulmonary penetration ratios 1. It is essential to monitor renal function and electrolytes closely, as both the infection and some antibiotics can affect kidney function, and adjust dosing based on renal function if needed. The choice of antibiotic may need modification once culture and sensitivity results are available, typically within 48-72 hours.

From the FDA Drug Label

Adult Patients: Urinary Tract Infections caused by Escherichia coli (including cases with secondary bacteremia), Klebsiella pneumoniae subspecies pneumoniae, Enterobacter cloacae, Serratia marcescens, Proteus mirabilis, Providencia rettgeri, Morganella morganii, Citrobacter diversus, Citrobacter freundii, Pseudomonas aeruginosa, methicillin-susceptible Staphylococcus epidermidis, Staphylococcus saprophyticus, or Enterococcus faecalis. Meropenem for injection is contraindicated in patients with known hypersensitivity to any component of this product or to other drugs in the same class or in patients who have demonstrated anaphylactic reactions to beta(β)-lactams.

For a patient with Klebsiella positive urosepsis, hyperchloremic metabolic acidosis, and a penicillin allergy, the recommended antibiotic would be ciprofloxacin (IV), as it is indicated for the treatment of urinary tract infections caused by Klebsiella pneumoniae subspecies pneumoniae 2. However, meropenem (IV) is contraindicated in patients with a known hypersensitivity to beta-lactams, which includes penicillin, so it may not be suitable for this patient due to the risk of cross-reactivity 3. Ciprofloxacin can be used with caution, but it is essential to monitor the patient's condition and adjust the treatment as needed.

• The patient's penicillin allergy should be carefully evaluated to determine the risk of cross-reactivity with other antibiotics.
• The treatment should be guided by the results of culture and susceptibility tests to ensure the chosen antibiotic is effective against the causative organism.

From the Research

Antibiotic Selection for Klebsiella-positive Urosepsis

• The selection of an antibiotic for Klebsiella-positive urosepsis should be based on local resistance patterns and the expected pathogen spectrum 4.
• Given the patient's penicillin allergy, alternative antibiotics such as carbapenems or cephalosporin/beta-lactamase inhibitor combinations can be considered 5.
• Broad-spectrum beta-lactam antibiotics, such as piperacillin/tazobactam, can be used as monotherapy, while cephalosporins should be combined with aminoglycosides or fluoroquinolones 5.

Considerations for Hyperchloremic Metabolic Acidosis

• Hyperchloremic metabolic acidosis can be a complication in patients with renal dysfunction, and its treatment should focus on addressing the underlying cause 6.
• In the context of urosepsis, the treatment of hyperchloremic metabolic acidosis may involve the use of bicarbonate or citrate supplements, as well as measures to avoid hyperkalemia 6.
• The patient's renal function and acid-base status should be closely monitored, and adjustments made to the antibiotic regimen as needed to minimize the risk of worsening renal function or metabolic acidosis 7, 8, 4.

Treatment Approach

• The treatment of urosepsis should involve a multidisciplinary approach, including urologists, intensive care specialists, and microbiologists 4.
• Early goal-directed therapy, including optimal pharmacodynamic exposure to antimicrobials, is critical in the management of urosepsis 8.
• The patient's response to treatment should be closely monitored, and adjustments made to the antibiotic regimen as needed to ensure effective treatment of the infection and management of any complications, including hyperchloremic metabolic acidosis 7, 5, 8, 4.