2. Objetivos de Aprendizaje
• Identificar las bacterias que pueden causar
IVU
• Describir las características de la cistitis y de la
pielonefritis
• Identificar los agentes antimicrobianos útiles
para el tratamiento
• Describir como se pueden prevenir las IVU
3. Microbiota normal del tracto urinario
• Uretra distal:
– Lactobacilos, Estafilococo, Estreptococos.
– Occasionalmente: Mycobacterium, Bacteroides,
Fusobacterium, Peptostreptococcus
• Resto de VU: Axénico
4. Defensas antibacterianas en las vías urinarias
• Orina (osmolalidad, pH, ácidos orgánicos)
• Flujo de la orina y la micción
• Mucosa del tracto urinario (actividad bactericida, péptidos, citoquinas)
• Inhibidores urinarios de adherencia bacteriana:
– proteína de Tamm-Horsfall, oligosacáridos de bajo peso molecular,
mucopolisacáridos de la vejiga, inmunoglobulina A secretora (SIgA),
Lactoferrina
• Respuesta Inflamatoria
– Neutrófilos polimorfonucleares (PMN)
– Citoquinas
• Sistema Inmune
– Inmunidad humoral, inmunidad celular
• Otros
– Secreciones prostáticas
5. Factores de riesgo para IVU
Age Female Male
All ages Previous urinary tract infection Lack of circumcision (children and young
adults)
Urologic instrumentation or surgery Urologic instrumentation or surgery
Urethral catheterization Urethral catheterization
Urinary tract obstruction, including calculi Urinary tract obstruction, including calculi
Neurogenic bladder Neurogenic bladder
Renal transplantation Renal transplantation
Adults Sexual intercourse Insertive rectal intercourse
Lack of urination after intercourse Vaginal colonization with E. coli in partner
Spermicidal contraceptive jellies Diaphragm use
Pregnancy Lower socioeconomic group Diabetes
Sickle cell trait in pregnancy
Older age Functional or mental impairment Functional or mental impairment
Estrogen deficiency (loss of vaginal
lactobacilli)
Prostatic enlargement
Bladder prolapse Condom catheter drainage
8. Presentación clínica de IVU
Síntoma Signo Mecanismo
Disuria Inflamación aguda de la vejiga, incomodidad tras la
contracción durante la micción.
Frecuencia y urgencia edema inflamatorio ↓ capacidad de la vejiga ↓
distensibilidad y dolor debido a la distensión
Hematuria Tracto urinario irritado, edematoso, sangrado con la
micción.
Sensibilidad suprapúbica Debido a la palpación y la compresión de vejiga
inflamada.
Escalofríos y sudoración Fiebre Cascada inflamatoria que resulta en una respuesta
febril.
Dolor de costado (se puede
irradiar a región inguinal, a
menudo sordo y constante)
Dolor en ángulo
costo vertebral
Edema renal repentino, ↑presión y distensión
capsular.
9. Manifestaciones
• Acompañada de flujo vaginal?
• Si ITS? (N. gonorrhoeae, C. trachomatis, C.
albicans y T vaginalis)
• NO IVU (90% VPP)
10. Agentes etiológicos más comunes
Bacterial Pathogen
Percentage with
Pathogen
Gram-negative
Escherichia coli 50–80
Klebsiella species 6–12
Proteus species 4–6
Enterobacter species 1–6
Morganella species 3–4
Gram-positive
Enterococcus species 2–12
Coagulase-negative staphylococci (S saprophyticus) 5–15
Group B streptococci 2–5
13. Uropatogénesis: Adhesinas y sus receptores
Adhesin Genetic Sequence Receptor Comments
Type 1 fimbriae (MS) Pily fimH, fimB, fimE Mannosylated proteins on
epithelial cells (uroplakin la) and
PMNs
Bind to Tamm-Horsfall protein (THP)
and SIgA
P fimbriae (MR) papG (class la) Gal-a 1-4 (P blood group
antigen)
Rare
(papG J96)
papGAP (class II) Strongly associated with
pyelonephritis and bacteremia
(papGIA2)
papG (class III) Cystitis; predominates among
patients with urinary tract
abnormalities and males
(prsGjx)
MR, mannose-resistant; MS, mannose-sensitive; PMN, polymorphonuclear neutrophil; SIgA, secretory immunoglobulin A.
14. Uropatogénesis: Adhesinas y sus receptores
Adhesin Genetic Sequence Receptor Comments
S/F1C fimbriae (MR) Sfa/fac Sialyl-(a-2-3) galactoside Adherence inhibited by THP
Type F1C (MR) Foe Undetermined Possibly associated with
pyelonephritis
G fimbriae (MR) Terminal N-acetyl-D-
glucosamine
M fimbriae (MR) Galactose-N-acetyl-
galactosamine
Type 3 fimbriae (mrk ABCDF) Blood group M (glycophorin A) Contribute to biofilm formation; E
gene present in 16% of first-time
cystitis isolates
Dr family (fimbriated
and nonfimbriated)
Drb operon; adhesin (E
gene); Afa El-5; Afa F
Dr blood group antigen
component of DAF (decay
accelerating factor) and type IV
collagen
MR, mannose-resistant; MS, mannose-sensitive; PMN, polymorphonuclear neutrophil; SIgA, secretory immunoglobulin A.
25. Figure 1 This diagram shows the key stages in the formation
of infection stones
Thomas B and Tolley D (2008) Concurrent urinary tract infection and stone disease: pathogenesis,
diagnosis and management
Nat Clin Pract Urol doi:10.1038/ncpuro1254
26. Figure 2 This plain kidney–ureter–bladder radiograph shows two infection stones
(arrows) on a patient's right side
Thomas B and Tolley D (2008) Concurrent urinary tract infection and stone disease: pathogenesis,
diagnosis and management
Nat Clin Pract Urol doi:10.1038/ncpuro1254
28. Tratamiento de las IVU
Infection Category Antimicrobial Regimen
Uncomplicated cystitis Orally for 3 days:
Local E coli resistance
<20% to TMP-SMX
Trimethoprim-sulfamethoxazole DS 160/800 mg (Bactrim DS,
Septra DS) twice daily or
Trimethoprim (Bactrim, Septra) 100 mg twice daily or
Nitrofurantoin macrocrystals (Macrodantin) 50–100 mg four
times daily or
Nitrofurantoin monohydrate macrocrystals (Macrobid) 100 mg
twice daily or
Fosfomycin tromethamine (Monurol) single 3-g dose for only 1
day
29. Tratamiento de las IVU
Infection Category Antimicrobial Regimen
Uncomplicated cystitis Orally for 3 days:
Local E coli resistance
>20% to TMP-SMX Ciprofloxacin (Cipro) 250 mg twice daily or
Norfloxacin (Noroxin) 400 mg twice daily or
Levofloxacin (Levaquin) 250 mg daily
30. Tratamiento de las IVU
Infection Category Antimicrobial Regimen
Complicated/recurrent
cystitis Same as above unless culture and sensitivity dictate change
Postcoital Orally once:
Trimethoprim-sulfamethoxazole SS 80/400 mg 0.5 to 1 tablet
or
Ciprofloxacin 250 mg or
Levofloxacin 250 mg
Intermittent
Same as uncomplicated acute cystitis, begin with symptom
onset
31. Tratamiento de las IVU
Infection Category Antimicrobial Regimen
Mild pyelonephritis Oral 7 to 14 days:
Gram-negative Ciprofloxacin 500 mg twice daily or
Norfloxacin 400 mg twice daily or
Levofloxacin 250 mg daily or
Gram-positive
Amoxicillin-clavulanic acid 875/125 mg (Augmentin) twice
daily
32. Tratamiento de las IVU
Infection Category Antimicrobial Regimen
Severe pyelonephritis
Intravenous until afebrile 24 to 48 hours, then oral to complete
7–14 days of therapy:
Gram-negative Ciprofloxacin 400 mg twice daily or
Levofloxacin 500 mg daily or
Cefoxitin (Mefoxin) 2 g every 8 hours with or without
aminoglycoside or
Cefotaxime (Claforan) 1 to 2 g two to four times daily with or
without an aminoglycoside or
Gram-positive Ampicillin 3 g every 6 hours or
Piperacillin-tazobactam 3.375 g (Zosyn) q 6 h or
Ampicillin-sulbactam 3/1.2 g (Unasyn) q 6 h or
33. Preguntas
1. Porqué la deficiencia de estrógenos es un
factor de riesgo para IVU?
2. Cuál es la diferencia entre “Axénico” y
“estéril”?
3. Qué es la proteína de Tamm-Horsfal?
4. Cómo actúa la Nitrofurantoína?
5. Cuál es la frecuencia de E. coli resistente a
TMP en Colombia?
34. Lecturas recomendadas
• Arch G Management of Antimicrobials in
Infectious Diseases Impact of Antibiotic
Resistance, 2nd Edition 2010
• Mandell, Douglas, and Bennett's Principles
and Practice of Infectious Diseases,2010.
Chapter 69
