UGI Flashcards
UTIs in children
UTIs in children: more common in those under the age of 2
Proteus mirabilis
Virulence factors
- Proteases
- Haemolysins
- Biofilm formation
- Urease production
Increase in alkalization will cause stones to form
Lactobacilli characteristics
- Gram + rods, non-spore forming
- Facultative or strict anaerobes, produce lactic acid
- Rarely cause UTIs do not grow in urine well
Psuedomonas biofilm development
Diagnosis of UTIs
- Clean catch urine specimen (unspun, midstream)
- White and red blood cells, bacteria
- Culture and sensitivity tests
- ~20% of patients w/UTIs do not have pyuria
- No simple test to distinguish between upper from lower UTIs
Urine -> smells like ammonia, toxic to kidneys (alkaline -> urine struvite crystals)
Proteus mirabilis
Serotypes of E. coli in UTI
~85% of community- acquired, ~50% of hospital acquired UTIs
Uncomplicated vs Complicated UTIs
• Uncomplicated UTI
– no specific pre-disposing factors
– no structural abnormalities, etc.
• predisposing anatomic, functional, or metabolic abnormalities -> Complicated UTI
– requires more aggressive evaluation and follow- up
– definition is often imprecise
Pathogenesis of UTI pic
Clinical Outcomes of UTIs
• Prostatitis: spectrum of disorders, some infections (E. coli most common)
– acute bacterial prostatitis is most serious but least common (chronic more common)
– reflux of urine from urethra into prostate ducts
• Epididymitis: microorganisms can enter from prostate via ejaculatory duct
– pathogens vary in younger men vs older
– predisposing factors include prostatitis, indwelling urinary catheters, urologic surgery
Chronic UTI associated with which bacteria
E. coli
Sx and location of infection of UGT
Virulence factors contributing to UTIs
– Adhesins (pili, fimbriae, etc.)
– Ig proteases
– Hemolysins (get cytokine release, inflammation) – Ureases (i.e. P. mirabilis)
– Siderophore expression
– Factors promoting colonization and movement
Tamm-Horsfall Protein
Bladder host defense
- binds specifically to type 1 fimbriated E. coli
- key urinary anti-adherence factor serving to prevent type 1 fimbriated E. coli from binding to the urothelial receptors
UTI Treatment
- Usually antibiotics
- Drug and length depends on patient’s history and infecting microbe
- Sensitivity tests useful in selecting most effective drug
Protective components of UGT
– Antimicrobial properties of urine (high urea conc., immunoglobulins, etc.) – Presence of normal microflora
most common site of healthcare-associated infection, accounting for more than 40% of the total # reported
UT infections due to catheterization
Asymptomatic Bacteriuria
Relatively common finding
- Present in ~5% of unselected medical outpatients, 10% pregnant patients at term, also in hypertensive and diabetic patients
- Anatomic obstruction increases incidence
- Nearly all patients with indwelling catheter w/open drainage for more than 48 hrs
Recurrent UTIs
- 3 or more UTIs within a 12-month period
- Relapse
- Re-infection
- New infection
- Predisposing factors
- 20 - 25% women w/acute uncomplicated cystitis have 2 or more infections/yr
UTI vs. STI
Juxtaposition of urinary and genital tracts in
vertebrates is a source of confusion
- UTI = Urinary tract infection. May or may not be transmitted by sexual activity – the more general term
- STI = Sexually transmitted infection –more narrowly specific
- Not all UTIs are sexually transmitted, and not all STIs manifest their symptoms and/or pathology
in the urogenital tract
Normal microflora of vagina
– More diverse, influenced by hormones
– Newborn girls colonized w/ Lactobacilli, vaginal flora becomes more diverse over time
– Lactobacilli become more prominent at puberty
Epidemiology of UTIs
2nd most common type of infection in the body*
Women: especially prone to UTIs (20-40% develops a UTI during her lifetime)
- Men: not as common as in women but can be very serious when they do occur
- US women that develop a UTI: 20% will have a recurrence
- Women who experience three or more UTIs are likely to continue experiencing them
Acute uncomplicated cystitis, Recurrent cystitis in young women, Acute cystitis in young men, Acute uncomplicated pyelonephritis, Asymptomatic bacteriuria in pregnancy
What bacteria
- Escherichia coli • Klebsiella pneumoniae
- S. saprophyticus • Proteus mirabilis
Complicated urinary tract infection bacteria
- E. coli
- Enterococcus species
- K. pneumoniae
- Pseudomonas aeruginosa
- P. mirabilis
Normal Microflora
• Urethra
– Lactobacilli
– Streptococci
– Coagulase-negative Staphlococci
Staphylococcus saprophyticus seasonality
Summer
(summer time sex)
Ascending vs Descending UTIs
- Descending is far less common
- Ascending – microorganisms may travel from urethra bladder kidney
What allows for organisms to stick to catheters
Biofilms
UPEC serotypes
Pregnant women w/UTIs
untreated - increased risk of delivering low birth weight / premature infants
– Smooth muscle relaxation
– Urethral dilation
– Greater chance to progress to pyelonephritis
UPEC (Uropathogenic E. coli)
Characteristics
primary cause of UTIs
Gram – rods, normal habitat is gastrointestinal
tract of humans and animals
distinguished by acquired genes (iron acquisition, siderophores) virulence-
distinct UPEC associated biosynthetic pathways
UTI Risk Factors
- being female
- recent sexual intercourse
– abrasions, etc.
- recent use of a diaphragm with spermicide • history of recurrent infection
- urinary catheter
Abbreviated work-ups for UTIs
- Leukocyte-esterase test
- Nitrates → nitrites: what does this mean?
- UTI symptoms in the presence of leukocytes are considered adequate to make a diagnosis of UTI
Urine cultures w/ 105 CFUs have defined infection
Catheterization predisposes you to
– obstruction -> bacterial glycocalyx
– encourages formation of encrustations and infection
stones consisting of urea, other complex substances
– local infections (urethritis, periurethral abscess, epididymitis, and prostatitis)
Organisms predominately responsible for remaining UTIs (~15% community- acquired, ~50% of hospital-acquired)
– Staphylococcus saprophyticus
– Proteus mirabilis
– Klebsiella species
– Mycoplasma and Ureaplasma
– Candida
Primary cause of UTIs pathogen
UPEC (Uropathogenic E. coli)
- Cause of UTIs (usually young, sexually active women)
- Infrequent asymptomatic colonizer of UT
- Infections have been on the increase
Staphylococcus saprophyticus
Adhesion support for differnt types of organisms
Uropathogenic E. coli (UPEC)
Key virulence features
- Type I (cystitis)
- P pili (pyelonephritis)
Additional:
- α-hemolysin
- Siderophore
- Pathogenicity islands
Biofilms
are groups of microorganisms, often many species, growing on surfaces encased in “slime”
- Inert and living substances can be destroyed
- Multi-step process involving communication
Lactobacilli
• In addition to genitourinary tract also found in
– mouth, intestines, stomach
uropathogenicity of Staphylococcus saprophyticus
– novel cell wall-anchored adhesin
– redundant uro-adaptive transport systems
– urease
Summary 1 of STDs
STD summary 2
STI epi
• Affect both sexes, all socio-economic groups; Disproportionately affect:
– women, infants of infected mothers
– adolescents and young adults
– communities of color
– 15-24-year-olds represent ~ 1⁄4 of the sexually active population nearly 1⁄2 of all new STDs
“New” STIs
– Giardia lamblia - Protozoan
– Amoeba sp. - Protozoan
– Shigella sp., E. coli – True Bacteria
Vaginal discharge seen in
VAGINITIS:
– Trichomoniasis
– Candidiasis
CERVICITIS:
– Gonorrhoea
– Chlamydia
Urethral discharge seen in
Gonorrhoea
Chlamydia
Genital ulcer caues
Syphilis
Chancroid
Genital herpes
Lower abdominal pain seen in what STI
Gonorrhoea
Chlamydia
Mixed anaerobes
Scrotal swelling seen in which STDs
Gonorrhoea
Chlamydia
Inguinal bubo what is it/ seen in what stds
what is it:
Painful enlarged
inguinal lymph nodes
seen in:
LGV
Chancroid
Neonatal conjunctivitis in what stds
Gonorrhoea
Chlamydia
Anaerobic Gram negative bacteria and GYN Infections includes what organisms
Prevotella bivia and disiens,
Bacteriodes fragilis (common in abscesses)
• Virulence factors: capsules, etc. (adherence)
Gonorrhea: Epidemiology
- occurs only in humans (no other known reservoir)
- transmittedprimarilybysexualcontact,veryrare fomite transmission
- major reservoir is the asymptomatically infected individual
- infectionincreaseslikelihoodofHIVinfection
Gonhrea age relation
- Men (~95% have symptoms): generally restricted to the urethra – purulent urethral discharge, dysuria
- Women: site of infection is cervix – vaginal discharge, dysuria and abdominal pain
Gonorrhea
Neisseria gonorrhoeae: Characteristics
- Neisseria gonorrhoeae: Gram – diplococci
- non-motile, non-spore forming
- Fastidious
- oxidase +
- outer surface w/ multiple antigens