L37- Urogenital Infections I Flashcards
______ are the only colonized regions of the urogenital system
anterior urethra
vagina
list the protective components of the urogenital system
- antimicrobial properties of Urine (urea, Igs)
- presence of normal microbiota
lower UTI Sxs
(cystitis) frequency urgency burning dysuria suprapubic tenderness
upper UTI Sxs
(cystitis + pyelonephritis) fever, chills n/v hypotension costovertebral angle tenderness
UTI risks:
- (1) is main risk for recurrence of UTIs in women
- (2) risks of pregnant women with untreated UTIs
1- >3 UTIs
2: inc risk of delivering baby with low birth weight / premature
- smooth muscle relaxation
- urethral dilation
- greater chance to progress to pyelonephritis
describe normal flora of urethra
- Lactobacilli
- Strep. spp.
- coagulase neg Staph. spp.
describe normal flora of vagina
-highly diverse, influenced by hormones
Newborns: Lactobacilli –> vaginal flora becomes more diverse over time –> Lactobacilli becomes more prominent at puberty
Lactobacilli:
- (1) locations
- (2) key microbial features
- (rarely/often) cause of UTI
1- mouth, intestines, stomach, vagina, urethra
2- gram- rod, facultative/strict anaerobes, Lactic Acid producing
3- rare, grows poorly in urine
list the risk factors for UTI
- F > M
- h/o recurrent infections
- recent sex –> abrasions
- recent use of diaphragm with spermicide
- urinary catheter
- diabetics
- h/o long-term antibiotic use
- lifestyle/behavioral practices
UTIs are most (as/des)-cending
ascending- travels from urethra –> bladder –> kidney
descending is way less common
UTI clinical presentations
-sometimes asymptomatic
- frequency, painful urination, dysuria
- general malaise and pain
- pressure, fullness, lower abdominal pain
- cloudy, blood-tinged urine, strong odor
Fever in pyelonephritis
Asymptomatic bacteriuria:
- (rare/common)
- (2) has about 100% risk of development
- (3) will inc the incidence
1- common
2- all Pts with catheters w/ open drainage for >48hrs
3- anatomic obstruction
Define recurrent UTIs- indicate main bacteria
3 or more UTIs in 12 mos
- relapse, reinfection, or new infection
- there are predisposing factos
20-25% women w/ acute uncomplicated cystitis have 2 or more infections per year
-mainly different types of E. coil
compare uncomplicated vs complicated UTIs
Complicated:
- pre-disposing factors (vs 0) like anatomic, functional, metabolic abnormalities
- more aggressive evaluation and f/u
- often polymicrobial
Uncomplicated:
- no particular pre-disposing factors
- 95% monomicrobial
compare risk factors of uncomplicated and complicated UTIs
Uncomplicated: female, extremes of age
Complicated: catheters, immunosuppression, urinary tract anomalies, antibiotic exposure
list the complications of long-term catheterizations
- UTIs
- obstruction –> bacterial glycocalyx / biofilm
- infection stones (urea + other substances)
- local infections: urethritis, periurethral abscess, epididymitis, prostatitis
____ is the main cause of cystitis and pyelonephritis
E. coli- UPEC (uropathogenic E. coil), normally in GIT
-gram- rods in general
list main virulence factors for E. coli
(gram- rod)
- adhesins: pili, fimbriae
- IgA protease
- hemolysin –> CK release + inflammation
- siderophore expression
- other factors promoting colonization and movement
UPEC = (1)
- (2) and (3) are main virulence factors (include infection type)
- (4) are additional virulence factors
1- uropathogenic E. coli
2- Type I pili –> cystitis
3- P pili –> pyelonephritis
4- α-hemolysin, siderophore, pathogenicity islands
list the factors of host defense against UTIs
- high urine flow (+ unidirectional) and cell exfoliation
- innate and adaptive immune responses
w/in bladder:
- antimicrobial properties
- competition w/ Fe sequestering proteins
- Tamm-Horsfall Protein
describe function of Tamm-Horsfall protein
(anti-adherence factor)
binds type I fimbriated E. coli to prevent UPEC binding to urothelial receptors
list some other non-E. coli / non-UPEC causal agents of UTIs
- Staph. saprophyticus
- Proteus mirabilis
- Klebsiella spp.
- Mycoplasma, Ureaplasma
- Candida
(1) causes ‘honeymoon cystitis, where it mostly affects (2) people.
1- staph. saprophyticus
2- young, sexually active women; high incidences in the summer
list the key factors of Staph. saprophyticus that contribute to uropathogenicity
- urease
- novel cell wall anchored adhesin
- redundant uro-adaptive transport system
list the key virulence factors of Proteus Mirabilis
- proteases
- hemolysins
- biofilm formation
- urease production
describe the key symptomatic feature of Proteus mirabilis UTI
- ammonia smelling urine
- toxic to kidneys
- alkaline urine may lead to urine struvite crystals
describe diagnostic process for UTIs
1) clean catch urine –> looking for RBCs, WBCs, bacteria –> culture / sensitivity testing
20% UTIs have no pyuria –> neg. culture f/u:
2) leukocyte esterase test, Nitrites (via bacterial conversion of nitrates)
explain the tests in a Urinalysis related to UTI
- epithelial cells (<5): indicates good sample
- WBC (<5): pyuria if >10
- RBC (<5): hematuria
- leukocyte esterase (absent): positve = pyuria or WBC present
- Nitrites (absent): positive = bacteria present due to nitrate reduction
- pH (4.5-8): more alkaline indicated urease producing bacteria
(1) is the most serious form of prostatitis with (2) as the common cause via (3) mechanism
1- acute bacterial prostatitis (least common though)
2- E. coli
3- reflux of urine from urethra into prostate ducts
Epididymitis:
- (1) route of bacterial inoculation to tissue
- causal pathogens vary based on (2)
- (3) predisposing factors
1- enter from prostate via ejaculatory duct
2- age (young v old)
3- prostatitis, indwelling catheters, urological surgery
E. Coli:
- gram(+/-) (coccus/rod)
- urease(+/-)
- nitrite(+/-)
1- gram- rod
2- urease-
3- nitrite+
Klebsiella pneumoniae:
- gram(+/-) (coccus/rod)
- urease(+/-)
- nitrite(+/-)
1- gram- rod
2- urease+
3- nitrite+
Staph. saprophyticus:
- gram(+/-) (coccus/rod)
- urease(+/-)
- nitrite(+/-)
1- gram+ coccus
2- urease+
3- nitrite-
(novobiocin resistance)
Vaginitis:
- (1) types and distributions
- (2) Sxs
1-
bacterial vaginosis (BV), 40-45%
vulvovaginal candidiasis (VVC), 20-25%
trichomoniasis, 15-20% (STI)
2- discharge, vulvar itching, irritation, odor
Bacterial Vaginosis:
- results from (1)
- mostly presents as (2), but can present as (3)
- most common in (4) group
- may lead to increase risk of (5)
1- disruption of vaginal flora –> replaced by certain overgrowth
2- asymptomatic
3- malodorous discharge (thin, white or gray), pain, itching, burning vagina
4- reproductive women
5- inc in HIV transmission
Bacterial Vaginosis Dx (mainly)
- examine discharge (to differentiate from candidiasis or trichomonas)
- ‘clue cells’ are most indicative
- fewer than normal lactobacilli (especially in polymicrobial BV)
- vaginal pH > 4.5 is suggestive of BV
describe Amsel Criteria
(for bacterial vaginoisis, must have at least 3 of 4 findings):
-vaginal pH: >4.5
- > 20% per HPF clue cells on wet mount
- positive amine (or ‘whiff’ test)
- homogenous, non-viscous, milk-white discharge adherent to vaginal walls
define clue cells
(indicative of bacterial vaginosis)
epithelial cells covered with small Gram- rods
What are the alternate or ‘other’ diagnostic tools for Bacterial vaginosis
Vaginal Gram stain (Nugent criteria)- normally abundant Gram+ lactobacilli –> mixed flora indicates BV
DNA Probe
New Ones:
- PIP, proline aminopeptidase
- sialidase tests
