A 35-year-old woman from Delhi presents with 3 weeks of fever, diarrhoea, and abdominal distension. Stool culture grows *Salmonella typhi* sensitive to ceftriaxone and fluoroquinolones. She has completed 10 days of IV ceftriaxone and is now afebrile with improving symptoms. What is the most appropriate next step for continuation of therapy?

Explanation

## Step-Down Therapy in Enteric Fever ### Rationale for Oral Fluoroquinolone Step-Down **Key Point:** Enteric fever requires a total of 14 days of antimicrobial therapy. After 7–10 days of parenteral therapy (ceftriaxone) and clinical improvement (defervescence, resolution of systemic symptoms), step-down to oral fluoroquinolone (ciprofloxacin 500 mg twice daily) for the remaining 5 days completes the course. **High-Yield:** Fluoroquinolones achieve excellent intracellular penetration and high bioavailability when given orally, making them ideal for step-down therapy in *Salmonella typhi* infections. Oral ciprofloxacin is equivalent to IV therapy in the continuation phase. ### Duration and Transition Protocol | Phase | Duration | Agent | Route | |---|---|---|---| | **Acute phase** | 7–10 days | Ceftriaxone 2 g IV 8-hourly | IV | | **Step-down phase** | 5 days | Ciprofloxacin 500 mg BD | Oral | | **Total course** | **14 days** | — | — | **Clinical Pearl:** The transition to oral therapy is safe once the patient is afebrile, tolerating oral intake, and showing clinical improvement. Continuing IV therapy beyond clinical response increases cost and risk of line-related complications without additional benefit. ### Treatment Timeline ```mermaid flowchart TD A[Enteric fever diagnosed<br/>Blood/stool culture positive]:::outcome --> B[Start IV ceftriaxone<br/>2 g 8-hourly]:::action B --> C{After 7-10 days:<br/>afebrile +<br/>clinically improving?}:::decision C -->|Yes| D[Switch to oral ciprofloxacin<br/>500 mg BD]:::action D --> E[Continue 5 days<br/>Total therapy: 14 days]:::action E --> F[Clinical cure<br/>Discharge]:::outcome C -->|No| G[Continue IV ceftriaxone<br/>Reassess for complications]:::action ``` **Mnemonic:** **14-day rule** = **7–10 days IV** + **5 days oral** = **14 total days** for uncomplicated enteric fever. ### Why Other Options Are Suboptimal - **Discharge without further antibiotics:** Incomplete therapy (only 10 days) risks relapse and persistent bacteremia; enteric fever requires 14 days total. - **Continued IV ceftriaxone:** Unnecessary after clinical response; increases cost, line infection risk, and phlebitis without therapeutic benefit. - **Chloramphenicol:** Obsolete in India due to high resistance (40–60%); no role in modern enteric fever management.