Tratamiento de Infecciones Urinarias

Tratamiento de primera línea para mujeres con cistitis no complicada

La European Urology Association recomienda fosfomicina trometamol (3g dosis única), nitrofurantoína (100mg dos veces al día por 5 días) o pivmecilinam (400mg tres veces al día por 3-5 días) como tratamiento de primera línea para mujeres con cistitis no complicada 1, 2, 3
Fosfomicina trometamol es efectiva en una dosis única de 3g por 1 día para el tratamiento de cistitis no complicada en mujeres 1, 3
Nitrofurantoína macrocristales es efectiva en dosis de 50-100mg cuatro veces al día por 5 días para el tratamiento de cistitis no complicada en mujeres 1, 3
Pivmecilinam es efectiva en dosis de 400mg tres veces al día por 3-5 días para el tratamiento de cistitis no complicada en mujeres 1, 3

Tratamientos alternativos cuando los de primera línea no son adecuados

Cefalosporinas como cefadroxilo pueden ser utilizadas en dosis de 500mg dos veces al día por 3 días si la resistencia local de E. coli es <20% 1, 3
Trimetoprima puede ser utilizada en dosis de 200mg dos veces al día por 5 días, pero no se recomienda en el primer trimestre de embarazo 1, 3
Trimetoprima-sulfametoxazol puede ser utilizada en dosis de 160/800mg dos veces al día por 3 días, pero no se recomienda en el último trimestre de embarazo 1, 3

Tratamiento en hombres

Trimetoprima-sulfametoxazol es efectiva en dosis de 160/800mg dos veces al día por 7 días para el tratamiento de infecciones urinarias en hombres 1, 3
Fluoroquinolonas pueden ser prescritas de acuerdo con pruebas de susceptibilidad locales para el tratamiento de infecciones urinarias en hombres 1, 3

Consideraciones importantes

Diagnóstico

El diagnóstico de cistitis no complicada puede realizarse con alta probabilidad basándose en síntomas del tracto urinario inferior y ausencia de secreción vaginal 2
No es necesario realizar cultivo de orina en mujeres con síntomas típicos de cistitis no complicada 2
Se recomienda cultivo de orina en casos de sospecha de pielonefritis aguda, síntomas que no se resuelven o recurren dentro de 4 semanas después del tratamiento, mujeres con síntomas atípicos o mujeres embarazadas 1, 2

Duración del tratamiento

Se recomienda tratar las infecciones urinarias no complicadas con la duración más corta razonable de antibióticos, generalmente no más de 7 días 4
Para mujeres cuyos síntomas no se resuelven al final del tratamiento o recurren dentro de 2 semanas, se recomienda realizar cultivo de orina y prueba de susceptibilidad antimicrobiana 1, 3

Precauciones y advertencias

Las fluoroquinolonas son altamente eficaces pero deben reservarse para usos más importantes debido a su potencial de daño colateral 5
Los β-lactámicos (excepto pivmecilinam) tienen eficacia inferior y más efectos adversos en comparación con otros antimicrobianos para infecciones urinarias 5
Amoxicilina o ampicilina no deben usarse para tratamiento empírico debido a su relativamente pobre eficacia y alta prevalencia de resistencia antimicrobiana 5

Infecciones recurrentes

Para pacientes con infecciones recurrentes, se recomienda considerar profilaxis antimicrobiana continua o post-coital cuando las intervenciones no antimicrobianas han fallado 6
En mujeres posmenopáusicas, se recomienda considerar el reemplazo de estrógeno vaginal para prevenir infecciones urinarias recurrentes 6

Casos especiales: Infecciones urinarias por organismos resistentes

Para cistitis simple por Enterobacteriaceae resistentes a carbapenémicos, se recomienda una dosis única de aminoglucósido 7, 8
Para infecciones urinarias no complicadas por Enterococcus resistente a vancomicina, se recomienda fosfomicina 3g PO dosis única, nitrofurantoína 100mg PO cada 6 horas o ampicilina en dosis altas o amoxicilina 500mg IV o PO cada 8 horas 7, 8

Fosfomycin Treatment for Urinary Tract Infections

Clinical Context and Timing

The European Association of Urology recommends that UTIs recurring more than 2 weeks after initial treatment be considered reinfections rather than treatment failures, and should be treated as new episodes with appropriate antimicrobial therapy based on culture results 9, 10
For women whose symptoms do not resolve by the end of treatment or recur within 2 weeks, urine culture and antimicrobial susceptibility testing should be performed, and the infecting organism should be assumed resistant to the originally used agent, according to the European Urology guidelines 9
Retreatment with a 7-day regimen using another agent should be considered for infections recurring within 2 weeks, as suggested by the European Urology guidelines 9
UTIs recurring more than 2 weeks after symptom resolution or caused by a different pathogen are classified as "reinfections" rather than treatment failures or relapses, as stated by the Journal of the American College of Radiology 10, 11

Appropriate Use for Recurrent UTIs

The American Urological Association recommends that each new UTI episode occurring more than 2 weeks after previous treatment can be treated with fosfomycin 3g single dose 9
Urine culture should be obtained to confirm diagnosis and guide therapy for recurrent episodes, as recommended by the European Urology guidelines 9
For prevention of recurrent UTIs, fosfomycin can be used prophylactically at 3g every 10 days, according to The Journal of Urology 12
This prophylactic dosing schedule differs fundamentally from repeated daily dosing for a single acute episode, as noted by The Journal of Urology 12

Clinical Decision Algorithm

If symptoms recur within 2 weeks, obtain urine culture and susceptibility testing, assume resistance to fosfomycin, and use a different antimicrobial agent for 7 days, as recommended by the European Urology guidelines 9
If a new UTI occurs more than 2 weeks after treatment, obtain urine culture before treatment, and fosfomycin 3g single dose is appropriate first-line therapy, according to the European Urology guidelines 9, 10, 11
For patients with recurrent UTIs, consider prophylactic fosfomycin 3g every 10 days for 3-6 months, and discuss risks, benefits, and alternatives of antibiotic prophylaxis, as suggested by The Journal of Urology 12

Complicated UTIs

For complicated UTIs or those with risk factors for resistance, culture-guided therapy is essential, as recommended by the European Urology and Journal of the American College of Radiology guidelines 9, 10

Management of Uncomplicated Urinary Tract Infections

Patient Selection and Diagnosis

The presence of significant bacteriuria is confirmed by a culture showing >100,000 CFU/mL, according to the American Academy of Pediatrics 13
To confirm an uncomplicated UTI, the patient should be a non-pregnant woman without anatomic/functional urinary tract abnormalities, as recommended by the European Association of Urology 14, 15
The patient should have no signs of upper tract involvement, such as fever >38°C, flank pain, or costovertebral angle tenderness, as indicated by the European Association of Urology 15

Treatment and Management

If the organism is Proteus mirabilis, nitrofurantoin should be stopped immediately due to intrinsic resistance, as advised by the European Association of Urology 14
Nitrofurantoin is not recommended for upper tract involvement (pyelonephritis) due to insufficient blood/tissue concentrations, according to the European Association of Urology 15
Trimethoprim-sulfamethoxazole 160/800mg twice daily for 3 days may be considered as an alternative if local resistance is <20%, as suggested by the European Association of Urology 15

Cefdinir Use in Uncomplicated E. coli Urinary Tract Infections

Position of the Infectious Diseases Society of America (IDSA)

Cefdinir may be used for uncomplicated E. coli UTIs, but it is not a first‑line agent and should be reserved for cases where preferred antibiotics (nitrofurantoin, fosfomycin, or trimethoprim‑sulfamethoxazole) cannot be used. 16
Beta‑lactam agents, including cefdinir, are classified as alternative agents for uncomplicated cystitis; 3‑ to 7‑day regimens are appropriate only when other recommended agents are unavailable. 16
The IDSA states that beta‑lactams have inferior efficacy and more adverse effects compared with other UTI antimicrobials and should be used with caution for uncomplicated cystitis. 16

When Cefdinir May Be Considered

Cefdinir should be prescribed only when first‑line agents are contraindicated because of allergy, intolerance, or documented resistance. 16

Safety and Resistance Concerns

Fluoroquinolones should be reserved for important uses other than acute cystitis despite their high efficacy, due to concerns about collateral damage. 16
Amoxicillin and ampicillin should never be used empirically because resistance rates worldwide exceed 20 % in most regions. 16

Guidance for Upper‑Tract Infections (Pyelonephritis)

Oral beta‑lactam agents (including cefdinir) are less effective than other agents for pyelonephritis; if they are used, an initial intravenous dose of a long‑acting parenteral antimicrobial such as ceftriaxone is required. 17, 18
Cefdinir must not be used as monotherapy for pyelonephritis without a preceding parenteral dose of ceftriaxone or an aminoglycoside, because oral beta‑lactams are inadequate for upper‑tract infections. 17, 18