From the Guidelines
For step B urine coverage in patients allergic to penicillins, I recommend using cefdinir as an alternative treatment option, as it is highly unlikely to be associated with cross-reactivity with penicillin allergy due to its distinct chemical structure, as stated in the study by 1. This recommendation is based on the most recent and highest quality study available, which suggests that the risk of cross-reactivity between penicillins and cephalosporins is lower than historically reported, with a reaction rate of 0.1% as stated by the Joint Task Force on Practice Parameters 1. Some key points to consider when choosing an antibiotic for step B urine coverage in patients allergic to penicillins include:
- The severity of the penicillin allergy reaction, with severe reactions requiring more caution
- The time elapsed since the index reaction, which can affect the risk of recurrence
- The use of alternative antibiotics with a lower risk of cross-reactivity, such as cefdinir, cefuroxime, cefpodoxime, and ceftriaxone, as recommended by 1
- The importance of obtaining cultures before starting therapy in complicated cases to ensure appropriate coverage, as suggested by 1
- The need to consider local resistance patterns, patient-specific factors like renal function, and severity of infection when choosing an antibiotic, as stated by 1. It's also worth noting that, according to the study by 1, the risk of recurrence of an allergic reaction upon re-exposure to the antibiotic or the risk of cross-allergy with other antibiotics depends on several factors, including the nature, intensity, onset, and duration of symptoms concerning the use and indication of the suspected drug. Additionally, the study by 1 concludes that the implementation of a more liberal approach towards patients with a suspected antibiotic allergy may result in the use of smaller spectrum antibiotics with fewer side effects, less toxicity, and potentially lower risks of antibiotic resistance. However, the avoidance of certain antibiotics in case of suspected true (and severe) antibiotic allergy should be strongly advised, as stated by 1. Overall, the choice of antibiotic for step B urine coverage in patients allergic to penicillins should be guided by a careful assessment of the patient's allergy history, the severity of the reaction, and the potential risks and benefits of different antibiotic options, as recommended by 1.
From the Research
Urine Coverage for Allergic to Penicillins
- For patients allergic to penicillins, several alternative antibiotics can be used to treat urinary tract infections (UTIs) 2, 3.
- First-line options include nitrofurantoin, fosfomycin, and pivmecillinam, which have been shown to be effective against common uropathogens 2, 3.
- Second-line options include oral cephalosporins such as cephalexin or cefixime, fluoroquinolones, and β-lactams such as amoxicillin-clavulanate, although their use may be limited by resistance patterns 2.
- For patients with extended-spectrum β-lactamases (ESBLs)-producing Enterobacteriales, treatment options include nitrofurantoin, fosfomycin, pivmecillinam, amoxicillin-clavulanate, finafloxacin, and sitafloxacin 2.
Treatment Options for Specific Types of UTIs
- For UTIs caused by ESBLs-E coli, treatment options include nitrofurantoin, fosfomycin, pivmecillinam, amoxicillin-clavulanate, finafloxacin, and sitafloxacin 2.
- For UTIs caused by ESBLs-Klebsiella pneumoniae, treatment options include pivmecillinam, fosfomycin, finafloxacin, and sitafloxacin 2.
- For UTIs caused by carbapenem-resistant Enterobacteriales (CRE), treatment options include ceftazidime-avibactam, meropenem/vaborbactam, imipenem/cilastatin-relebactam, colistin, fosfomycin, aztreonam, and cefiderocol 2.
Comparative Effectiveness of Antibiotics
- A network meta-analysis of randomized trials found that ciprofloxacin and gatifloxacin were the most effective treatments for UTIs, while amoxicillin-clavulanate was the least effective 4.
- Another study found that nitrofurantoin was at least comparable to other common UTI treatments in terms of clinical and bacteriological cure 5.