Treatment of Morganella morganii Infection in a 66-Year-Old Female
For Morganella morganii infection in a 66-year-old female, targeted antibiotic therapy with ciprofloxacin is recommended as first-line treatment if the organism is susceptible, with carbapenems being the preferred alternative for resistant strains. 1, 2
Diagnostic Approach
- Obtain appropriate cultures (blood, urine, sputum, or wound) to confirm M. morganii infection and determine antibiotic susceptibility 3
- Consider imaging studies to identify the extent and location of infection 3
- Monitor inflammatory markers (C-reactive protein, erythrocyte sedimentation rate) to assess response to treatment 3
First-Line Treatment Options
- Ciprofloxacin (500-750 mg orally twice daily) is FDA-approved for M. morganii infections and effective for skin/soft tissue infections, which are the most common presentation 1, 4
- Treatment duration typically ranges from 7-14 days depending on infection site and severity 2
- For severe infections or in immunocompromised patients, consider initial intravenous therapy before transitioning to oral treatment 5
Alternative Treatment Options (for resistant strains or severe infections)
- Carbapenems (imipenem or meropenem) are highly effective against M. morganii and recommended for severe infections or resistant strains 2, 5
- Third-generation cephalosporins combined with aminoglycosides (particularly gentamicin) have shown efficacy in treating M. morganii infections 5, 6
- Piperacillin/tazobactam can be considered as an alternative based on susceptibility testing 4
Special Considerations
- M. morganii frequently demonstrates resistance to multiple antibiotics, including first-generation cephalosporins, ampicillin, and amoxicillin 2, 7
- Always base final treatment on antimicrobial susceptibility testing results, as resistance patterns vary 3, 5
- For polymicrobial infections (present in approximately 58% of M. morganii cases), ensure coverage for all isolated organisms 4
- In elderly patients (>65 years), monitor renal function closely as they have increased risk of mortality with M. morganii bacteremia 2
Treatment Monitoring
- Assess clinical response within 48-72 hours of initiating therapy 3
- For bacteremia or severe infections, repeat blood cultures to confirm clearance 2
- Monitor for development of resistance during treatment, particularly with prolonged therapy 5, 7
- Consider source control measures (drainage, removal of infected devices) if applicable 2
Prognosis and Follow-up
- Complete recovery is expected with appropriate antibiotic therapy in immunocompetent patients 4
- Higher mortality rates (up to 41%) are observed in elderly patients, those with ICU admission, and patients with comorbidities 2
- Follow-up cultures may be warranted in cases of persistent or recurrent symptoms 3
Common Pitfalls to Avoid
- Failing to obtain appropriate cultures before initiating antibiotics 3
- Underestimating M. morganii's potential for antibiotic resistance, particularly to beta-lactams 5, 7
- Not considering M. morganii as a potential pathogen in elderly or immunocompromised patients 2, 7
- Inadequate duration of therapy, especially for deep-seated infections 5