Clinical Scorecard: Elevated Incidence of Bacteremia and Resistance to Fluoroquinolones During a Shigellosis Outbreak Among Individuals with Homelessness and Opioid Use Disorder in Philadelphia, PA

At a Glance

Key Highlights

• 31.3% bacteremia rate among hospitalized shigellosis patients, significantly higher than historical norms
• Near-universal resistance to fluoroquinolones and β-lactams; trimethoprim-sulfamethoxazole (TMP-SMX) remains the only reliably susceptible oral antibiotic
• Outbreak predominantly affected individuals with housing insecurity and opioid use disorder, with high injection behavior prevalence

Guideline-Based Recommendations

Diagnosis

• Confirm shigellosis via stool or blood culture and/or PCR-based stool pathogen panel
• Identify Shigella species and serotype through public health laboratory confirmation

Management

• Avoid fluoroquinolones and β-lactams due to high resistance rates
• Use trimethoprim-sulfamethoxazole as the preferred oral antibiotic treatment when susceptibility is confirmed
• Monitor for invasive disease manifestations including bacteremia

Monitoring & Follow-up

• Perform blood cultures in hospitalized patients to detect bacteremia
• Monitor clinical response and complications such as dehydration, electrolyte imbalance, and organ failure
• Track antibiotic susceptibility patterns to guide therapy

Risks

• High risk of invasive shigellosis and bacteremia in patients with homelessness and opioid use disorder
• Potential for treatment failure due to multidrug resistance
• Risk of severe complications including death, although rare

Patient & Prescribing Data

Hospitalized patients with shigellosis, predominantly experiencing homelessness and opioid use disorder

TMP-SMX demonstrated the highest susceptibility among isolates; fluoroquinolones and ceftriaxone showed high resistance and are not recommended

Clinical Best Practices

• Screen for housing insecurity and opioid use disorder in patients presenting with shigellosis
• Obtain both stool and blood cultures to assess for invasive infection
• Use susceptibility data to guide antibiotic selection, prioritizing TMP-SMX when appropriate
• Implement infection control measures to prevent fecal-oral transmission in high-risk populations
• Coordinate care with public health authorities for outbreak management and surveillance

References

• High rates of bacteremia and fluoroquinolone resistance during an outbreak of shigellosis among people experiencing homelessness and opioid use disorder in Philadelphia, PA