Micro Flashcards
define significant bacteriuria
> 10^5 cfu/ml, used in research and smwhat in the clinical def. of UTI
lower UTI includes?
bladder and urethra, upper is kidney and upper urinary tract
most common causes of dysuria
cystitis most comm, also vaginitis, chlamydia, bacterial causes below the clinical def, and unknown causes
most comm culprit of UTI
E. coli, 95% from GI tract, also Staph saprophyticus in sex. active young F
age distrib. of UTI and gender
- Infants = males > F
- 3-50 y/o = F»_space;» M
- elders = incr. incid in both, but still more comm in F
what effect does birth control choice have on UTI incidence
- highest incid. in those using diaphragms and spermicidal gel b/c of alterations in the flora/pH of vagina as well as anatomical alterations,
- lower incid in oral contraception
- note from nun studies that intercourse itself puts women at 4xs higher risk of UTI
Pregnancy and UTI
10% of all pregnant women will have bacteriuria (2xs higher than expected) and of those, if untreated, 25% will prog. to pyelonephritis
-can increase risk of fetal loss
symp. of pyelonephritis
fever/chills
flank pain (cvat)
asymptomatic
symp and ddx of UTI
\+/- fever frequency dysuria turbid urine hematuria suprapubic discomfort asymptomatic cystitis -ddx = microscopic urinanalysis, gram stain, urine culture, blood culture (prn)
route of infection in UTI
us. ascending from urethral trauma, intercourse, instrumentation, diaphragm use. less than 5% hematogenous seeding from signif. bacteremia.
steps in pathogenesis of UTI
adhesion, colonization, invasion, phase variation
describe the phase variation of UTI bacteria
they display antigenic variation through switching which pilus gene is expressed so that immune system surveillance is disrupted
types of pili (fimbriae) employed by uropathogenic e. coli
type 1 - mannose sens (how they attach to uroepith - but mannose also express. on PMNs)
P-fimbriae - think pyelonephritis b/c the bact switches to this and this cause p.n. preferentially
what do the siderophores and exotoxin hemolysin provide for the bacterium
these virulence factors liberate iron from RBCs thru their lysis necc for bact. growth
host defense mech from UTI
- environ = high salt and urea content
- uroepith sloughing = slough colonies too
- flushing = urine washes colonies out
- antib. = secreted IgA
factors predisposing to UTI
- chronic infections (lumenal narrowing)
- tumors - blockage
- kinking, abnml vessels - anat. anomaly
- calculi - obstruct flow
- scar tiss
- vesicoureteral reflux
prevention of UTI
good hygiene
remove catheters ASAP
correct anatomic abnmlties
-rarely- prophylactic antibiotics
Tx of UTI
IF SYMPTOMATIC : tx M 1 wk, F 3 days w/ flouroquinolone, cephalosporin, trimeth/sulfa, aminoglycoside
Tx of pyelonephritis
aminogylcosides best, then flouroquinolones, then trimeth/sulfa, and others don’t do as well
incid of which STD is highest in US
chlamydia, HPV has similar incid. but is not reportable so numbers not certain
second highest incidence STD
GC and also HSV has similar incid but not reportable
_______has twice the incid of HBV and HAV but half that of TB
syphilis, higher in TN and memphis esp.
STDs causing ulcers
1 syphilis, HSV, Chancroid, LGV (c.trachomatis L1-3),
STDs causing drips
GC, Chlamydia (C. trach D-K), Trichomoniasis, Bacterial vaginosis, Candidiasis, ureaplasma
STDs causing warts
HPV (esp 6 + 11), 2 Syphilis, Molluscum Contagiosum (pox),
HSV 1 + 2 charact.
- lg, ds DNA virus, enveloped
- neurotropic latency
- 2 prefers below the belt, 1 above, but both can cross over - route of infection is determinant
- 10% can cause meningitis
Tx for HSV
ACV - not curative
DDx of HSV
Blood PCR, fab assays, Tzanck smear
what does Tzanck smear show for HSV?
multinucleated giant cells w/ inclusion bodies from viral replication
S+S HSV
- can be preceded by flu-like prodrome
- group PAINFUL vesicular lesions on erythematous base recurring in a dermatomal distrib. 2 wks after initial infection, second. usu. not as bad b/c of preformed antib.
- 1+2 look similar in genital infection
- active infection can be transmitted to baby during birth
- meningitis us. resolves on its own unlike bacterial (look for cytopathic effect in csf culture for virus)
neonatal HSV
- tx mostly at parturition - C-section if active dz
- zosterform rash on skin w/ eye mouth involvmt
- CNS or disseminated - bad - encephalitis, organ failure, 75% die
immune rxn to HSV
- controlled by cell-mediated immunity so defects in this (neonates w/o fully dvlped immune system, AIDS) can lead to massive problems. Also, secondary infection us. not as bad b/c of preformed antib.
causative agent of syphilis
Treponema pallidum - a spirochete
tests for syphilis
non-specific : RPR and VDRL
specific: FTA-abs
not vis. by gram stain, but darkfield microscopy can reveal if done well
mandatory report to health dept
presentation of 1,2,3 syph
1 = PAINLESS chancre @ site of infection 2 = maculopapular rash (incl hands and feet last) 3 = granulomas (gummas), CNS dementia, aortic aneurysm
tx for syph
penicillan (benzothene preparation for IM XR), if allergy - desens. then tx
what strain of C. trachomatis causes lymphogranulosum venarium (LGV)
L1-3
S+S of LGV
swollen inguinal lymph glands that may ulcerate, rare
s+s of chancroid
single or multiple ulcers that may look v. similar syphilis but v. painful, rare
charact. of Neisseria gonorrhoeae (GC)
- oxidase + (aerobic), gram -, no capsule, extracellular “parasite”
- sheds LPS which causes inflamm.
- displays antigenic variation thru multiple genes for pili so no perm. immunity
tests for GC (gonococcus)
- NAAT (nucleic acid amplific. tests)
- grow on Thayer-Martin (choc. agar w/ antib. for nml flora)
- gram stain of smear (look for gram- cocci and PMNS) if polys but no cocci then presume Ct
S+S of GC
- cervicitis, urethritis, PID, rectal infections, pharyngitis, conjunctivitis in newborn, (all same for Ct), but disseminated infection to endocard, meningitis, arthritis w/ rash is unique to GC
- mucopurulent exudate
- PAINFUL urination
tx for GC
ceftriaxone (or cefixime), PLUS azithromycin or doxycycline (for coverage of Ct which is presumed present until proven otherwise)
*flouroquinolones no longer rec. bc of resistance
tx sexual contacts
**silver nitrate in eyes of newborn for GC doesn’t work for Ct
S+S of PID
- dull to sev. abdm pain
- adnexal tenderness and cervical motion tenderness
- fever
- poss. cervicitis
- may result in sterility, abcesses, hospitalizations, chronic pain
what strains of C. trachomatis causes urethritis, cervicitis, PID?
Ct D-K
charact. of Ct
- obligate intracell. bact w/o peptidoglycan cell wall (no beta lactams, doesn’t gram stain)
- two phase replication cycle (Elementary body - the extracellular infecting phase, Reticulate body - the replicating form intracell - form CYTOPLASMIC inclusion bodies)
dx of Ct
urine NAAT, not detectable w/ gram stain, cell culture v. diff, rapid antigen test is not as sensitive
tx of Ct
azithromycin or doxycycline AND ceftriaxone for presumed concurrent GC, tx sexual contacts
**silver nitrate in eyes of newborn will not help w/ Ct or infant pn.
S+S of Ct
cervicitis, urethritis, PID, rectal infections, pharyngitis, conjunctivitis in newborn, infant pn, (all same for GC), infant pneumonia is unique to Ct
-less purulent than GC, milky discharge, dysuria
infant pn. from Ct
afebrile, staccato cough w/ tachypnea (like pertussis but w/o whoop), wheezing rare, may be concurrent w/ conjunctivitis
T/F Ct/GC infections are often inapparent/subclinical
T
Bacterial Vaginosis charact. and S+S
- represents an imbalance of nml flora (loss of lactobacilli)
- us. not painful, no dysuria
- anaerobes - smells bad - 10% KOH releases amines (fishy) = whiff test
- look for “clue cells” = epith. cells w/ dots indicating bacteria (us. gardnerella, mobiluncus and a combination of others)
- mod. white or gray, adherent, homogenous discharge that coats vagina, pH > 4.5tx
agents of BV
Gardnerella vaginalis, Mobiluncus, oth. anaerobes
tx of BV
Metronidazole, or clindamycin cream
