From the Guidelines
The most appropriate antibiotic choice for this bacterial isolate is amoxicillin-clavulanate, given its susceptibility (S) with an MIC ≤2, as well as other options such as cefepime, ceftazidime, ceftriaxone, ciprofloxacin, levofloxacin, and trimethoprim-sulfamethoxazole, which all demonstrate good susceptibility 1. For a urinary tract infection specifically, nitrofurantoin would be appropriate as it shows susceptibility with an MIC of 32. If this is a more serious infection requiring intravenous therapy, the carbapenems (imipenem, meropenem) or piperacillin-tazobactam would be effective choices. The choice of antibiotic should ultimately depend on the site of infection, patient factors (allergies, renal function), local antibiotic stewardship guidelines, and the need for oral versus intravenous administration. Narrower spectrum antibiotics should be preferred when possible to reduce the risk of developing resistance. It's also important to consider the potential for errors in interpretation of antimicrobial susceptibility testing results, as highlighted in the study by 1, which emphasizes the importance of understanding the clinical breakpoints and normalized error probabilities for different antibiotics. In this case, the provided antibiotic susceptibility results suggest that the bacterial isolate is sensitive to multiple antibiotics, allowing for a range of treatment options. However, it's crucial to prioritize the use of antibiotics with the narrowest spectrum of activity and the lowest risk of promoting resistance, as guided by local antibiotic stewardship policies and the specific clinical context of the patient.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Antibiotic Susceptibility
- The provided list of antibiotics and their corresponding susceptibility breakpoints is as follows:
- AMOX/CLAVULANATE: S <=2
- CEFAZOLIN: NR <=4 2
- CEFEPIME: S <=0.12
- CEFTAZIDIME: S <=1
- CEFTRIAXONE: S <=0.25
- CIPROFLOXACIN: S <=0.06
- GENTAMICIN: S <=1
- IMIPENEM: S <=0.25
- LEVOFLOXACIN: S <=0.12
- MEROPENEM: S <=0.25
- NITROFURANTOIN: S 32
- PIP/TAZOBACTAM: S <=4
- TRIMETHOPRIM/SULFA: S <=20
- These breakpoints are used to determine the susceptibility of bacteria to specific antibiotics, which is essential in guiding antibiotic therapy 3, 4.
Treatment Options
- For urinary tract infections (UTIs) caused by antibiotic-resistant Gram-negative bacteria, treatment options include:
- Nitrofurantoin
- Fosfomycin tromethamine
- Pivmecillinam
- Oral cephalosporins (e.g., cephalexin, cefixime)
- Fluoroquinolones
- β-lactams (e.g., amoxicillin-clavulanate) 3
- For UTIs caused by ESBL-producing Enterobacteriales, treatment options include:
- Nitrofurantoin
- Fosfomycin
- Pivmecillinam
- Amoxicillin-clavulanate
- Finafloxacin
- Sitafloxacin 3
- For UTIs caused by carbapenem-resistant Enterobacteriales, treatment options include:
- Ceftazidime-avibactam
- Meropenem/vaborbactam
- Imipenem/cilastatin-relebactam
- Colistin
- Fosfomycin
- Aztreonam
- Amoxicillin-clavulanate
- Aminoglycosides (e.g., plazomicin)
- Cefiderocol
- Tigecycline 3
Antibiotic Susceptibility Reporting
- Laboratory reporting of antibiotic susceptibility results can influence antibiotic prescribing practices 5.
- The new susceptibility categories ('susceptible, standard dosing regimen', 'susceptible, increased exposure', and 'resistant') introduce a paradigm shift in interpreting antibiotic susceptibility testing results 4.
- Physicians' perceived likelihood of coverage achieved by their usual empiric antibiotic regimen and minimum thresholds of coverage they would be willing to accept can vary depending on the infection source and severity 6.