What is the recommended treatment for asymptomatic bacteriuria caused by Raoultella planticola?

Management of Asymptomatic Bacteriuria from Raoultella planticola

Asymptomatic bacteriuria caused by Raoultella planticola should not be treated with antibiotics in most patient populations, as treatment does not improve clinical outcomes and may contribute to antimicrobial resistance. 1, 2

Definition and Diagnosis

• Asymptomatic bacteriuria is defined as the presence of significant bacteriuria without symptoms of urinary tract infection
• Diagnostic criteria:
  • For women: Two consecutive voided urine specimens with isolation of the same bacterial strain in quantitative counts ≥10^5 CFU/mL 1
  • For men: A single clean-catch voided urine specimen with one bacterial species isolated in a quantitative count ≥10^5 CFU/mL 1
  • For catheterized specimens: ≥10^2 CFU/mL identifies bacteriuria 1

Treatment Recommendations by Population

Populations Where Treatment is NOT Recommended:

• Premenopausal, non-pregnant women (A-I) 1, 2
• Diabetic women (A-I) 1, 2
• Older persons living in the community (A-II) 1, 2
• Elderly, institutionalized subjects (A-I) 1
• Persons with spinal cord injury (A-II) 1
• Catheterized patients while the catheter remains in situ (A-I) 1

Populations Where Treatment IS Recommended:

1. Pregnant women (A-I) 1, 2

   • Screen in early pregnancy and treat if positive
   • Duration of therapy: 3-7 days
   • Follow-up with periodic screening for recurrent bacteriuria

2. Before urologic procedures with risk of mucosal bleeding (A-I) 1, 2

   • Particularly before transurethral resection of the prostate
   • Initiate antimicrobial therapy shortly before the procedure
   • Discontinue after the procedure unless an indwelling catheter remains in place

3. Women with catheter-acquired bacteriuria that persists 48 hours after catheter removal (B-I) 1

   • Treatment may be considered but is not strongly recommended

Special Considerations for Raoultella planticola

Raoultella planticola is a gram-negative rod that has emerged as a potential pathogen in recent years 3, 4. While historically considered an environmental organism, it has been associated with various infections including urinary tract infections 5.

Key characteristics of R. planticola infections:

• Often seen in patients with comorbidities such as diabetes mellitus and renal failure 5
• Typically shows intrinsic resistance to ampicillin 5
• Can occasionally develop multidrug resistance, including carbapenem resistance through mechanisms like OXA-48-type carbapenemases 4

Clinical Pearls and Pitfalls

Pearls:

• Pyuria accompanying asymptomatic bacteriuria is NOT an indication for antimicrobial treatment (A-II) 1
• Urine culture is the gold standard for detection of asymptomatic bacteriuria, not dipstick or microscopy 2
• When treatment is indicated, select antibiotics based on susceptibility testing and local resistance patterns

Pitfalls:

• Treating asymptomatic bacteriuria when not indicated contributes to antimicrobial resistance
• Unnecessary treatment increases risk of antibiotic-associated adverse effects
• Misidentification of Raoultella species may be common, as they can be confused with Klebsiella species 4

Algorithm for Management

1. Confirm the diagnosis of asymptomatic bacteriuria with appropriate culture techniques
2. Determine if the patient belongs to a population where treatment is recommended
3. If treatment is indicated, obtain susceptibility testing to guide antibiotic selection
4. For R. planticola specifically, be aware of potential ampicillin resistance
5. Use the narrowest spectrum antibiotic effective against the isolate
6. Limit treatment duration to the recommended period for the specific indication