What is the recommended treatment for an elderly female patient with a urine culture positive for Streptococcus anginosus and Alloscardovia, indicating a presumed urinary tract infection (UTI) with Impaired renal function?

Treatment of Streptococcus anginosus and Alloscardovia UTI in Elderly Female with Impaired Renal Function

This elderly patient requires antimicrobial treatment only if she has localizing genitourinary symptoms (dysuria, urgency, frequency) or systemic signs of infection (fever, hemodynamic instability); if she is asymptomatic, treatment should be withheld regardless of positive urine culture. 1

Initial Assessment: Symptomatic vs Asymptomatic Bacteriuria

The critical first step is determining whether this represents symptomatic UTI or asymptomatic bacteriuria (ASB):

Symptoms Requiring Treatment 1

• Localizing genitourinary symptoms: dysuria (most specific), urgency, frequency, new or worsening incontinence, hematuria 1
• Systemic signs of infection: fever >38°C, hemodynamic instability, flank pain/costovertebral angle tenderness 1

Do NOT Treat If 1

• Patient has bacteriuria but lacks the above symptoms
• Patient presents with delirium, confusion, or falls alone without genitourinary symptoms or fever
• Patient is functionally or cognitively impaired without classic UTI symptoms

The IDSA strongly recommends against treating ASB in elderly patients, even those with functional/cognitive impairment, delirium, or falls, due to high certainty of harm (C. difficile infection, antimicrobial resistance) and low certainty of benefit. 1

If Treatment is Indicated (Symptomatic UTI)

Antibiotic Selection Considerations

For Streptococcus anginosus:

• This organism can cause serious complications including organ abscesses when bacteremic 2
• Typically susceptible to beta-lactams, including penicillins and cephalosporins 2

For Alloscardovia:

• Limited clinical data on this organism in UTI
• Generally susceptible to beta-lactams based on related species

Recommended Empiric Treatment with Renal Impairment

First-line options (adjust doses for renal function):

• Amoxicillin-clavulanate: Effective against both organisms, dose-adjust for creatinine clearance 3
• Cephalexin or other oral cephalosporins: Good coverage for streptococcal species, requires renal dose adjustment 1, 3

Avoid in this patient:

• Nitrofurantoin: Contraindicated with impaired renal function (CrCl <30 mL/min) 4, 3
• Trimethoprim-sulfamethoxazole: Requires dose adjustment and has increasing resistance rates 4, 5, 3

Treatment Duration 1

• Uncomplicated lower UTI: 5-7 days of appropriate antibiotic 1
• If upper tract involvement suspected: 10-14 days minimum 6
• Monitor closely given S. anginosus potential for abscess formation 2

Critical Pitfalls to Avoid

Do not treat based solely on:

• Positive urine culture without symptoms 1
• Pyuria alone (commonly present without infection in elderly) 4
• Mental status changes or falls without fever or genitourinary symptoms 1

Do not use nitrofurantoin with impaired renal function, as it is ineffective and potentially toxic 4, 3

Do obtain urine culture before treatment to guide antibiotic selection and confirm susceptibilities, especially given the unusual organisms isolated 1

Follow-Up Considerations

• Repeat imaging if fever persists >72 hours on appropriate antibiotics, given S. anginosus propensity for abscess formation 2
• Blood cultures should be obtained if patient appears systemically ill, as S. anginosus bacteremia can lead to metastatic infections 2
• Reassess renal function during treatment to adjust antibiotic dosing as needed 6