What are the IDSA recommendations for diagnosing and treating infectious diseases?

IDSA Recommendations for Diagnosing and Treating Infectious Diseases

The Infectious Diseases Society of America (IDSA) provides comprehensive evidence-based guidelines for diagnosing and treating various infectious diseases through systematic, standardized methodology using the GRADE approach (Grading of Recommendations Assessment, Development, and Evaluation) to rate evidence quality and strength of recommendations. 1

General Approach to Infectious Diseases

Diagnostic Principles

• IDSA recommends appropriate culture and susceptibility tests before initiating treatment to identify causative organisms and determine antimicrobial susceptibility, though empiric therapy may begin while awaiting results 1
• For specific infections like skin lesions from impetigo and ecthyma, Gram stain and culture of pus or exudates are recommended to identify causative organisms (Staphylococcus aureus and/or β-hemolytic Streptococcus) 1
• For diarrheal illnesses, diagnostic approaches should be guided by clinical presentation, with particular attention to fever or bloody diarrhea which warrant evaluation for specific enteropathogens 1

Treatment Principles

• Treatment decisions should be based on identified pathogens, antimicrobial susceptibility, infection site, and patient factors 1
• When anaerobic organisms are suspected, appropriate therapy should be administered alongside other antimicrobials 2
• For severe infections, prompt empiric therapy with broad-spectrum antibiotics is recommended while awaiting culture results 1

Disease-Specific Guidelines

Skin and Soft Tissue Infections (SSTIs)

• IDSA categorizes SSTIs as purulent (abscesses, furuncles, carbuncles) or non-purulent (cellulitis, erysipelas) with treatment approaches based on severity (mild, moderate, severe) 1
• For purulent SSTIs, incision and drainage is indicated for mild infections, while moderate to severe infections require antimicrobial therapy 1
• For non-purulent SSTIs, antimicrobial therapy is recommended with severity determining oral versus parenteral administration 1

Lyme Disease

• For high-risk Ixodes tick bites (identified Ixodes vector, highly endemic area, tick attached ≥36 hours), prophylactic treatment with single-dose oral doxycycline within 72 hours of tick removal is recommended 1
• For erythema migrans, treatment with either 10-day course of doxycycline or 14-day course of amoxicillin or cefuroxime axetil is recommended 1
• IDSA recommends against testing asymptomatic patients for Borrelia burgdorferi following an Ixodes tick bite 1

Infectious Diarrhea

• Patients with fever or bloody diarrhea should be evaluated for enteropathogens that may benefit from antimicrobial therapy, including Salmonella, Shigella, and Campylobacter 1
• All patients with acute diarrhea should be evaluated for dehydration, which increases risk of life-threatening illness and death 1
• When clinical or epidemic history suggests possible Shiga toxin-producing organisms, diagnostic approaches should detect Shiga toxin and distinguish E. coli O157:H7 from other STEC in stool 1

Aspergillosis

• For prevention in high-risk patients (e.g., allogeneic HSCT recipients), IDSA recommends placement in a protected environment to reduce mold exposure 1
• For diagnosis, tissue and fluid specimens should be submitted for simultaneous histopathologic/cytologic and culture examination 1
• Species identification should be performed for isolates with atypical growth or concerns for resistance 1

Special Considerations

Antimicrobial Resistance

• IDSA provides specific guidance for treating resistant organisms including extended-spectrum β-lactamase producing Enterobacterales (ESBL-E), AmpC β-lactamase-producing Enterobacterales, carbapenem-resistant Enterobacterales (CRE), and difficult-to-treat resistant Pseudomonas aeruginosa 3, 4
• Consultation with infectious diseases specialists is recommended for management of antimicrobial-resistant infections 3, 4

Prevention Strategies

• For tick-borne diseases, IDSA recommends personal protective measures including repellents (DEET, picaridin, IR3535, oil of lemon eucalyptus, PMD, 2-undecanone, or permethrin) 1
• Prompt removal of attached ticks using mechanical means (clean fine-tipped tweezers) is recommended, while burning or applying chemicals to remove ticks is discouraged 1

Common Pitfalls and Caveats

• Overdiagnosis of sepsis may lead to antibiotic overuse; IDSA recommends focusing on septic shock where evidence for immediate antibiotics is strongest 5
• Some antimicrobials have specific warnings; for example, ciprofloxacin is not a first-choice drug for pediatric patients due to increased adverse events related to joints/surrounding tissues 2
• Empiric therapy should be adjusted once culture and susceptibility results become available to ensure appropriate targeted therapy and prevent resistance development 2, 6
• Some pathogens may develop resistance rapidly during treatment (e.g., Pseudomonas aeruginosa with ciprofloxacin), requiring vigilant monitoring and potential therapy adjustments 2