From the FDA Drug Label
The following in vitro data are available, but their clinical significance is unknown Ciprofloxacin exhibits in vitro minimum inhibitory concentrations (MICs) of 1 μg/mL or less against most (≥ 90%) strains of the following microorganisms; however, the safety and effectiveness of ciprofloxacin in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled clinical trials ... Aerobic gram-negative microorganisms ... Klebsiella oxytoca
The MIC values should be interpreted according to the following criteria: For testing aerobic microorganisms other than Haemophilus influenzae , Haemophilus parainfluenzae, and Neisseria gonorrhoeaea: MIC (μg/mL)Interpretation ≤ 1 Susceptible (S) 2 Intermediate (I) ≥ 4 Resistant (R)
The Klebsiella oxytoca isolate has a MIC of ≤0.25 for ciprofloxacin, which is susceptible according to the provided criteria.
- Ciprofloxacin is likely to be effective against this isolate.
- The provided MIC value is within the susceptible range. 1
From the Research
Klebsiella oxytoca infection can be effectively treated with several antibiotic options based on the susceptibility results, with the best choices including fluoroquinolones, carbapenems, amoxicillin/clavulanate, ceftazidime, ceftriaxone, piperacillin/tazobactam, aminoglycosides, or trimethoprim/sulfamethoxazole, as supported by the most recent study 2. The organism shows resistance to ampicillin and cefazolin, and intermediate susceptibility to cefuroxime and tetracycline, so these should be avoided. Some key points to consider when choosing an antibiotic include:
- The infection site and severity
- Patient factors, such as renal function and allergy history
- Local antibiotic stewardship guidelines
- The potential for resistance, as highlighted in the study 2, which found increasing resistance to carbapenems. For a urinary tract infection, oral options like ciprofloxacin 500mg twice daily for 7 days or trimethoprim/sulfamethoxazole DS twice daily for 7-10 days would be appropriate. For more severe infections, intravenous options such as ceftriaxone 1-2g daily, piperacillin/tazobactam 3.375g every 6 hours, or meropenem 1g every 8 hours would be recommended, as suggested by the study 2. K. oxytoca is an opportunistic gram-negative pathogen that commonly produces beta-lactamases, explaining its resistance to ampicillin, but the susceptibility to beta-lactam/beta-lactamase inhibitor combinations like amoxicillin/clavulanate indicates these enzymes can be inhibited, as noted in the study 3. It's also worth noting that the study 4 found tigecycline to be an effective therapeutic option for the treatment of infections caused by K. oxytoca strains. However, the most recent and highest quality study 2 should be prioritized when making treatment decisions.