What to do next for a patient with persistent leukocytosis (elevated white blood cell count) despite 5 days of Tazocin (piperacillin/tazobactam) for a Hafnia alvei urinary tract infection (UTI) with pending blood culture results?

Management of Persistent Leukocytosis in ICU Patient with Hafnia alvei UTI on Tazocin

Continue Tazocin for a total of 7 days while awaiting blood culture results, and replace the urinary catheter immediately if it has been in place for more than 2 weeks. 1

Immediate Actions

Continue Current Antibiotic Therapy

• Do not change antibiotics at day 5 - patients with documented bacterial infections may require 5-7 days before clinical response occurs, even with appropriate therapy 1
• Complete a minimum 7-day course of piperacillin/tazobactam (Tazocin) for this catheter-associated UTI 2, 3
• The organism is documented as sensitive to your current regimen, making empiric broadening premature 1

Replace the Urinary Catheter

• Replace the catheter immediately if it has been in place >2 weeks, as biofilm formation can harbor persistent bacteria and prevent source control 2
• Catheter replacement is critical for treatment success in catheter-associated UTIs with persistent symptoms 2
• Hafnia alvei commonly colonizes catheters and can form biofilms resistant to antibiotic penetration 4

Reassessment Strategy at Day 5-7

Comprehensive Evaluation Required

• Perform meticulous physical examination focusing on new infection sources (perirectal abscess, line infections, sinusitis in intubated patients) 1
• Obtain chest imaging to evaluate for new pulmonary infiltrates or complications of underlying ILD 1
• Review all pending blood culture results - these are critical for determining if bacteremia is present 1
• Check inflammatory markers trend (CRP, procalcitonin if available) rather than isolated WBC count 1

Common Pitfalls in ICU Patients

• Leukocytosis alone is not treatment failure - ICU patients with lung cancer and ILD may have persistent leukocytosis from non-infectious causes (malignancy, steroids, stress response) 1
• Do not interpret persistent fever or leukocytosis as automatic antibiotic failure before day 5-7 1
• Avoid premature escalation to carbapenems, which should be reserved to preserve their activity against resistant organisms 1

Decision Points at Day 7

If Blood Cultures Are Positive

• Adjust antibiotics based on susceptibility results and continue for 10-14 days total 2, 3
• If Hafnia alvei grows from blood (urosepsis), consider switching to cefepime based on susceptibility, as this has been successful in published cases 4, 5
• Investigate for metastatic foci of infection requiring drainage 1

If Blood Cultures Are Negative and Patient Stable

• Continue Tazocin to complete 7 days if clinical improvement is evident (reduced fever, improved hemodynamics, stable or improving organ function) 1
• Persistent leukocytosis without clinical deterioration does not mandate antibiotic change in stable ICU patients 1
• Consider non-infectious causes: malignancy-related leukocytosis, medication effect (corticosteroids for ILD), stress response 1

If Clinical Deterioration Occurs

• Broaden coverage and investigate for uncontrolled infection source 1
• Consider imaging (CT chest/abdomen/pelvis) to identify occult abscesses or empyema 1
• Add empiric antifungal coverage (micafungin or anidulafungin preferred in ICU) if persistent fever >5-7 days despite appropriate antibacterial therapy 1
• Evaluate for Clostridioides difficile if diarrhea present 1

Specific Considerations for Hafnia alvei

Antibiotic Resistance Patterns

• Hafnia alvei produces inducible Bush group 1 beta-lactamase, which can cause resistance to many beta-lactams 4
• Your isolate is documented as sensitive to piperacillin/tazobactam, making it appropriate therapy 4
• If resistance develops or treatment fails, cefepime or fluoroquinolones (ciprofloxacin) are effective alternatives based on susceptibility 4, 5, 6
• Carbapenems, aminoglycosides, and cotrimoxazole typically show excellent activity 6

Source Control is Critical

• Hafnia alvei catheter-associated infections require catheter removal or replacement for cure 4
• Without adequate source control (catheter replacement), antibiotic therapy alone may fail 1, 4

When to Extend Treatment Duration

• Extend to 10-14 days if delayed clinical response (persistent fever, ongoing hemodynamic instability, slow improvement) 2, 3
• Complicated UTI with bacteremia warrants 10-14 days of therapy 3
• Immunocompromised state from malignancy may require longer treatment courses 3

What NOT to Do

• Do not stop antibiotics prematurely - discontinuation before day 7 in ICU patients with documented infection risks recurrent bacteremia and clinical deterioration 1
• Do not empirically escalate to carbapenems without documented resistance or clinical deterioration, as this promotes resistance 1
• Do not treat asymptomatic bacteriuria if obtained after completing therapy - only treat if symptomatic recurrence 1
• Do not add vancomycin empirically unless blood cultures suggest gram-positive infection or patient has risk factors for MRSA 1