🧠‑🤒 Meningitis in a Young Adult (Weekend)

A 24‑year‑old woman with no significant medical history presents on a Saturday evening with a 12‑hour history of fever (39 °C), worsening headache, photophobia, and neck stiffness. She is alert but irritable, with a heart rate of 110 bpm and blood pressure 120/70 mmHg. A head CT is not immediately available, and lumbar puncture (LP) cannot be done until Monday. You draw blood cultures and decide to start empiric antibiotics without delay.

Which empiric IV regimen is most appropriate while awaiting LP and cultures?

A) Ceftriaxone + Vancomycin
B) Ampicillin + Gentamicin
C) Vancomycin + Acyclovir
D) Meropenem alone
E) Vancomycin + Cefepime

🦠 HAP in a Haemodialysis Patient - in shock

Scenario:
A 68‑year‑old man on thrice‑weekly haemodialysis, recently transferred from a nursing home, develops a new fever (38.8 °C), worsening dyspnoea on BiPAP, hypotension (BP 85/50 mmHg) and tachycardia (115 bpm) five days into his admission for heart failure. A chest X‑ray shows a new right lower‑lobe infiltrate. His WBC is 18 × 10⁹/L and procalcitonin is elevated. Blood and sputum cultures are pending.

---

Question:
Which empiric IV regimen is most appropriate for this critically ill patient at high risk for ESBL‑producing organisms?

A) Vancomycin + Cefepime
B) Vancomycin + Piperacillin–Tazobactam
C) Vancomycin + Meropenem
D) Levofloxacin monotherapy

🤰Perforated Diverticulitis with Septic shock

Scenario:
A 63‑year‑old woman with recurrent diverticulitis presents with 24 hours of severe abdominal pain, fever (39 °C), rigors and hypotension (BP 85/50 mmHg). She appears "peritonitic" and is tachycardic at 120 bpm. CT scan shows free intraperitoneal air and colonic perforation. She has had three courses of broad‑spectrum antibiotics over the past year and now requires urgent laparotomy.

---

Question:
Which empiric IV regimen is most appropriate in this critically unwell patient to cover broad Gram‑negatives, anaerobes and Candida?

A) Piperacillin–tazobactam + fluconazole
B) Meropenem + micafungin
C) Cefepime + metronidazole + fluconazole
D) Piperacillin–tazobactam + micafungin
E) Meropenem alone

🦠 Severe Diverticulitis Requiring Admission

Scenario:

A 55‑year‑old woman presents with 48 hours of severe left lower‑quadrant pain, fever (38.5 °C), and inability to tolerate oral intake. She reports nausea and has been unable to pass flatus. On examination she is tender in the left lower quadrant with guarding but no peritonism. Her white cell count is 16 × 10^9/L, and CRP is elevated. A CT scan confirms uncomplicated diverticulitis (no abscess or perforation) with marked pericolic fat stranding. Given her pain, systemic features and inability to eat, you admit her for IV antibiotic therapy.

---

Question:
Which empiric IV regimen is most appropriate on admission?

A) Piperacillin–tazobactam
B) Ceftriaxone + metronidazole
C) Ertapenem
D) Meropenem
E) Ampicillin–sulbactam

🩸🦠🤒 Febrile Neutropenia—Empiric Anti‐Pseudomonal Coverage

Scenario:
A 57‑year‑old woman with acute myeloid leukaemia is 7 days post‑induction chemotherapy. Her absolute neutrophil count is 80 cells/µL. She presents with a single episode of fever (38.6 °C) and mild malaise. There are no focal signs of infection on exam, and chest X‑ray is clear.

---

Question:
Which empiric IV antibiotic is most appropriate to cover her risk of Gram‑negative bacteraemia, including Pseudomonas?

A) Cefepime
B) Piperacillin–Tazobactam
C) Meropenem
D) Ceftazidime
E) Aztreonam

🤮🫁Aspiration Pneumonia in a Healthy Young Adult

Scenario:
A 28‑year‑old man with no significant past medical history presents with a 36‑hour history of high fevers (39 °C), productive cough, and pleuritic right lower‑lobe chest pain. He reports binge drinking and one episode of vomiting the night before. On exam he is tachypnoeic (26 breaths/min), tachycardic (115 bpm), and has dullness to percussion with crackles at the right base. A chest X‑ray shows a right lower‑lobe consolidation. He appears ill and hypoxic on room air (SpO₂ 90%).

---

Question:
Which empiric IV antibiotic regimen is most appropriate for this patient?

A) Clindamycin
B) Ampicillin–sulbactam (Unasyn)
C) Piperacillin–tazobactam
D) Levofloxacin
E) Ceftriaxone plus metronidazole

Acute Pyelonephritis with possible Bacteraemia

Scenario:
A 35‑year‑old woman with a history of recurrent urinary tract infections presents to the ED with a 2‑day history of high fever (39.5 °C), chills, nausea, and severe left flank pain. On exam she is tachycardic (120 bpm), hypotensive (BP 90/55 mmHg), and appears unwell. Costovertebral angle tenderness is present on the left. Urine dipstick is positive for nitrites and leukocyte esterase. You draw blood and urine cultures; initial Gram stain of the blood cultures shows gram‑negative rods.

---

Question:
Which of the following is the best empiric IV antibiotic for this patient?

A) Ceftriaxone
B) Cefepime
C) Aztreonam
D) Piperacillin–tazobactam (Zosyn)
E) Meropenem

🦵🔥 Obesity with Cellulitis and Possible Bacteremia

Morbid Obesity with Cellulitis and Possible Bacteraemia

Scenario:
A 52‑year‑old man with a body mass index of 45 kg/m² presents with a 24‑hour history of rapidly spreading erythema and tenderness over his right lower leg. He is mildly febrile (39 °C) and tachycardic (110 bpm). There are no underlying chronic illnesses. Blood cultures are drawn given concern for early bacteraemia, and you plan admission for IV therapy covering Streptococcus spp. and MRSA.

---

Question:
Which empiric IV antibiotic is most appropriate for this patient?

A) Vancomycin
B) Daptomycin
C) Linezolid
D) Ceftaroline
E) Clindamycin

Vignette #2: Diabetic Boil Management – Optimising Empiric Therap

A 59-year-old man with poorly controlled type 2 diabetes (A1c 9.3%) presents with a painful 5 cm boil on his left thigh that has been progressively enlarging over 4 days. The lesion is fluctuant and surrounded by mild cellulitis. He is afebrile, and systemic symptoms are absent. You perform an I&D in the ED, and because no culture results are immediately available, you must decide on empiric oral antibiotic therapy to cover both MRSA and Streptococcus (especially Group B Streptococcus, frequently seen in diabetics).

---

Question:
Given the patient’s risk factors and the polymicrobial nature of diabetic skin infections, which of the following empiric oral antibiotic strategies is preferred?

A) Bactrim alone
B) Amoxicillin (or Augmentin) alone
C) Doxycycline alone
D) Amoxicillin + Bactrim
E) Oral Linezolid

---

✅ Preferred Answer: E) Oral Linezolid

Alternative Option: D) Amoxicillin + Bactrim

---

📘 Mini-Lesson & Explanation

1. The Case for Oral Linezolid (Preferred Option)

• Excellent Gram-Positive Coverage:
  Linezolid provides robust coverage against both MRSA and Streptococcus species, including Group B Streptococcus. This dual coverage is key in diabetic patients who are at risk for polymicrobial infections.

• High Oral Bioavailability:
  With nearly 100% bioavailability, oral linezolid ensures effective serum and tissue concentrations, making it ideal as a step-down or primary oral agent.

• Generic Availability:
  Although Linezolid once carried a high cost, it is now available as a generic, making it a cost-effective option under many circumstances.

• Safety and Efficacy:
  Despite its potential side effects (e.g. bone marrow suppression, peripheral neuropathy, serotonin syndrome), these risks are generally acceptable in short-course therapy for uncomplicated soft tissue infections, particularly when weighed against the risk of treatment failure.

2. The Case for Combination Therapy with Amoxicillin + Bactrim (Alternative Option)

• Rationale for Combination:

  • Bactrim Alone: Excellent MRSA coverage; however, its Streptococcus coverage is inadequate.

  • Amoxicillin Alone: Provides reliable coverage against Streptococcus, including Group B Streptococcus, but lacks activity against MRSA.

  • Together: The combination mitigates the gaps when either is used as monotherapy, covering both MRSA and Streptococcus.

• Considerations:

  • Safety & Adherence: While the combination offers broad-spectrum coverage, it involves administering two medications, which can increase pill burden and potential for drug interactions.

  • Local Resistance Patterns: In settings with high MRSA prevalence and documented clindamycin resistance, the combination might be second-best compared to the single-agent efficacy of Linezolid.

3. Why Other Options Are Less Suitable

• A) Bactrim Alone:
  Inadequate coverage for Streptococcus, a significant risk in diabetics.

• B) Amoxicillin (or Augmentin) Alone:
  Lacks any significant anti-MRSA activity; it fails to address the dual infection potential.

• C) Doxycycline Alone:
  Variable and unreliable activity against Streptococcus, which may lead to suboptimal outcomes in complicated diabetic skin infections.

---

🧠 Teaching Pearls

• Empiric Coverage in Diabetics:
  Diabetic patients frequently have infections caused by both MRSA and Streptococcus. Empiric therapy should cover both, taking into account local antibiotic resistance patterns.

• Oral Bioavailability:
  When considering oral therapy, ensure that chosen agents provide reliable systemic absorption. Linezolid excels in this aspect, with nearly equivalent bioavailability to its IV formulation.

• Drug Toxicity & Stewardship:
  Always weigh potential side effects and toxicity—Linezolid has noteworthy risks, so its use should be monitored closely, particularly for treatment durations beyond the typical 10-14 days in uncomplicated infections.