Uti, Endocarditis/meningitis & STIs Flashcards
Describe gonorrhoea bacteria
Gram negative diplococcus (coffee bean shaped)
Fastidious and susceptible to drying, requires transport medium
How is gonorrhea transmitted
Through contact of mucous membranes sexually or perinatally
Typically spread in the 20-25 age group
What are the clinical manifestations of gonorrhea
Pelvic inflammatory disease Pharyngitis Conjunctivitis Joint infection Neonatal conjunctivitis
How is gonorrhea diagnosed
Nucleic acid amplification testing
Or
Culture of urethral/cervical swabs
Benefits of nucleic acid amplification test?
More sensitive than a culture as it can also detext dead organisms
Can defect from urine sample (more comfortable)
What are some issues with urethral/cervical swabs
Less sensitive but very soecific
Resistance becoming a problem
What are treatments for gonorrhea
- Cefixime (oral beta lactam) or ceftriaxone (injection) combined with azithromycin incase of chlamydia co infection
- ciprofloxacin (flouroquinolone) although increasung resistance
Describe chlamydia bacteria
Chlamydia trachomatis causative agent
Obligate intracellular bacteria devoid of cell wall, can not be gram stained
Why can’t chlamydia bacteria be gram stained
Obligate intracellular bacteria that has no cell wall
Must be detected by molecular amplification or cultured
Describe chlamydia lifecycle
2 alternating forms
Reticulate body: actively replicating then ruptures creating elementary bodies
Elementary body: transmitted infectious form that enters cells and develops reticulate body
Reticulate -> replicate -> rupture
What cells does chlamydia infect
Urethral, cervical and conjunctivial epithelial cells
Describe chlamydia epidemiology
One of the most common stis
15-25 age range
Asymptomatic carriers common
What are clinical manifestations of chlamydia
Urethritis cervitis Pelvic inflammatory disease Proctitis (rectum inflammation) Reactive arthritis Conjunctivitis (esp in babies)
Describe chlamydia specimens
Men: urethral swabs and urine samples
Women: vaginal swabs, endocervical swabs, urine
How is chlamydia detected
Nucleic acid amplification test
How is chlamydia treated?
Tetracyclines ( doxycycline), azithromycin, erythromicin
No cell wall betalactam can not be used
Describe syphilis bacteria
Treponema pallidum
Tightly coiled spirochaete
Too fine to gram stain must use dark feild microscopy
What are the three stages of syphilis
Primary (localized) Secondary (systemic) Latent (asymptomatic) Tertiary (late) Congenital
Describe primary syphilis
1-4 weeks following contact
Chancre (painless ulcer) heals spontaneously
Describe secondsry syphilis
Skin rash, flu like symptoms, lymphadenopathy
Describe tertiary syphilis
Cardiovascular and neurological symptoms
Gumma (masses that appear on skin)
Describe congenital syphilis
Bone, teeth and brain damage
What is unique about a syphilis rash
Does not spare soles and palms
How is syphilis diagnosed
Dark feild microscopy for primary disease only! ( chancre)
Serology is main route of diagnoses
Specific tests used
How is syphilis treated
Penicillin treatment if choice, doxycycline if allergy
Longer treatment required if CNS involved
Hiv common coinfection so test for that
Describe herpes bacteria
Linear double stranded DNA virus
Neurotopic: invades nerves and becomes dormant reactive if regrowth
What is the clinical presentation of herpes?
Primary infection: fever, headache, myalgia, painful lesions, discharge, disuria, tender nodes
Latent: shedding virus without lesions
Describe recurrent herpes infections
Less severe than primary infection usually localized to genital area
Tingling/pain 50% of patients
Describe congenital herpes infection
Life threatening to baby if passed during birth
How is herpes diagnosed
Nuckeic acid amplification test
Swabs of local lesions
Culture on cells (less sensitive)
How is herpes treated
Antivirals
Long term prophylaxis if frequently recurrent
Describe UTI prevalance
50% of women have one before 30
Incidence decreases with age
About 25% of women experience a reinfection 6 months after first UTI
Define bacteriuria
Presence if bacteria in urine. Does not mean infection
Define asymptomatic bacteriauria
Prescence of bacteria and absence if symptoms
Usually clinically insignificant unless pregnant or undergoing unvasive procedures of urinary tract
What is an upper uti called
Pyelonephritis
What is a lower uti called
Cystitis and urethritis
How are utis classified
Location (upper/lower)
Condition of patient (complicated/uncomplicated)
Evolution (acute, chronic, recurrent)
Describe cystitis
Confined to bladder
Disuria, urinary frequency, urinary urgency
Absense of symptoms ir physical signs suggesting inflation at other sites withun urinary tract
What bacteria causes acute urethritis
Chlamydia trachomatis
Neisseria gonorrhea
What bacteria causes vulvitis
Contact dermatitis or allergic reaction
Candida albicans HSV infection
Define pyelonephritis
Clinical diagnosis that implies a more invasive infection INCLUDING THE KIDNEYS
Inflammation of kidney renal pelvis assumed as well as tenderness involving flank,nausea,chills,fever,headache
Define prostatistis
Inflammation or infection of the prostate gland
Define intrarenal abcess/perinephric abcess
Collection of pus in kidney or soft tissue surrounding kidney
Define uncomplicated UTIs
Patients with normal genitourinary tracts
Usually non pregnant premenopausal women
Describe complicated UTIs
Structural of functional abnormalities of the genitourinary tract
Pregnant women, elderly,men,children
Chronic symptoms, upper tract disease
Describe UTI relapse
Recurrence of infection by same organism after discontinued treatment
Describe UTI re infection
Recurrence of infection by different organisms after discontinued Treatment
What causes UTIs
Usually due to patients own intestinal flora ascending route of infection
Organisms enter urinary tract in retrograde fashion via the urethra
Complicating factors such as catheters tubes, surgery, stones allow organisns to enter tract and alter typical spectrum of organisms
What are risk factors for UTI
Aging Being female In males inter course or prostatic hypertrophy Urinary tract obstruction Impaired bladder innervation Hematogenous spread (through blood)
True or false a majority of UTIs are caused by a single pathogen
True
What bacteria is responsible for 90% of all UTIs
Enteribacteriacea
Gram negative, facultative anerobic bacilli
Common intestinal flora
What is the most commonly isolated pathogen in UTIs
Escherichia coli most commonly isolated 70% in all UTIs
What bacteria is responsible for a majority of community acquired UTIs
E.Coli
What is a major virulence factor in UTIs
Adherence
E.coli has fimbrae which bind to p blood group present on uro epithial cells in 99% of population
Describe hemolysins, colicin V in UTIs
Aid in resistance to complement dependent bactericidal effect of serum
Describe k antigen in UTI
Associated with uppee tract infections
Describe type I finbrae and uti
Inter bacterial binding and biofilm production
Describe proteus, morganella and providencia
Classical uti pathogens
Highly Motile, produce fimbrae
UREASE PRODUCING organisms
Increases urinary pH which leads to crystal formation and obstruct flow
CAUSE STONES AND CRYSTALIZATION
Swarm agar plate
What are biofilms
Colonization on catheter
Protects bacteria from hosts defenses and antibiotics
Describe uro-pathogen staph saprophyticus
1-5% if cystitis
Typically associated with younger sexually active females
Describe UTI dipstick testing
Interested in detection of nitrates and leukocytes produced by infection
Detection of nitrates: reasonably sensitive for gram negative bacteria but highly specific
Detection if leukocytes: sensitive but not specific
Need to find both
What is significant bacteruria in a urine culture defined as
10^5 bacteria/ml (10^8/litre)
Lower numbers may be significant in children or catheter specimens
Describe clean catch mid stream specimens
Most frequently used method
Urethra cleaned prior to collection
First void urine allowed to pass to clear urethra then mid stream collected in sterile containers
Describe collection bag samples
Used in children
Often contaminated
Most meaningful result is a negative culture
Describe indwelling catheter specimen collection
Urine obtained by inserting needle into catheter or through diaphragm
Preferably obtain through new catheter not old
Describe suprapubic aspiration specimen collection
Invasive.
Specimen obtained directly from bladder
How is a uti specimen transported
Bacteria grows rapidly in urine and sample must be sent as aoon as posible
If not in lab by 1-2 hours must be refrigerated
If not recieved in 24 hrs lab rejected
Unkess tranported by boric acid tube
Describe boric acid tube
Preserves and maintain viability of organism w/o further bacterial growth
Should all patients with UTI be cultured
No, we know what typically causes a UTI (e.coli) treat empirically
What treatment is used in uncomplicated cystitis
Nitrofuratonin (not empiracle choice anymore bc resistance)
Fosfomycin
TMP/SMX
Ciprofloxacin/noroxaxin if no other choice
What treatment is used in pyelonephritis
B lactam WITH amynoglycoside
Or
Ciprofloxcin (usually avoided)
What is endocarditis
An infection of the endocardial surface of the heart
The wall of the heart may be involved as well as infection may occur at structural defects
Who is particularly susceptible to endocarditis
Patients with artificial valves or other foreign materials
Descrube acute endocarditis
Presenting within 6 weeks
More virulent organism that causes damage more quickly (fever chills)
S.aureus and S. Pyrogenes responsible
Describe subacute and chronic endocarditis
Presenting from 6 weeks to 3 moths
Chronic after 3 months
Often caused by low virulence organisms with gradual destruction of valves
Viridians (alpha haemolytic) streptococci
What bacteria typically infects normal valves
S. Aureus; highly virulent
What bacteria are more likely to cause infection on abnormal valves
Low virulence, skin and oral microorganisms
Alpha haemolytic streptococci, enterococci and coagulase negative staphylococci
What are commonest organisms to cause natuve valve IE
Alpha haemolytic “viridians” streptococci
What organisms are commonest in PV IE
Coagulase negative staphylococci
What is bacteremia
Bacteria circulating in the blood
Describe endocarditis pathogenesis
Mucous membranes and skin colonized
Trauma = bacteremia
Adherence (promoted by fibrin, platelet aggregation and endothelial damage)
Further platelet fibrin deposition takes place
Vegetations develop after bacterial division
Vegetarions develop with dormant organisms
Vegetations fragment and embolize other organs
What heart valve complications can arise from infection
Cauliflower shaped vegetations may develop of valves
Inflammation may destroy valve
Small emboli in arteries = myocardial infection
Abscessed may develop in the heart muscle = impair electrical conduction
What are brain consequences from endocarditis
Micro emboli = confusion or coma
Stroke
Abscesses
Memegiris may occur from ongoing bacteremia or emboli
What are other consequences from endocarditis
Kidney: renal artery obstruction; inflammation and damage
Other:
Emboli in spleen, eyes, extremities or other organs
Blood vessels weakened stretched and burst
What risk factors can be identified when diagnosing endocarditis
Previous heart disease Dental or other surgical procedures Intravenous drug use Recent heart surgery Long standing in dwelling lines
What are tools for diagnosis for endocarditis
Blood cultures (positive in 90% of cases) Echocardiography (recognition if vegetation’s)
How long is endocarditis treated
At LEAST 4 weeks
How is endocarditis treated
Combonation treatments, especially with penicillin and aminoglycoside combos
Describe endocarditis prevention
Prophylactic antibiotics following at risk dental and surgical procedures
Define meningitis
Inflammation of fhe membranes covering rhe brain and spinal cord
Can be acute or chronic
What js encephalitis
Inflammation of brain tissue, not to be confused with meningitis
What is acute meningitis
Severe and sudden onset
Headache
Neck stiffness
Confusion
What causes acute meningitis
Streptococcus pneumoniae (kids and adults) Neisseris meningitidis (esp. young adults) Haemophilus influenzae (esp.children) Listeria monocytogenes (esp, babies and elderly)
What are other causes of acute meningitis
Viral causes (less severe)
Enteroviruses (summer/fall)
Arboviruses (vector transmission)
Herpes viruses
What kind if menigitis does not cause outbreaks
Streptococcus pneumoniae
True or false there is a vaccine for neisseria menjngitidis
True! Used during outbreaks
What type of meningitis is virtually eliminated
Haemophilus influenzae thanks to vaccine!
Describe intial pathogenesis for meningitis
- nasopharyngeal colonization
- local invasion
- bacteriemia
- meningeal invasion
- bacterial replication in subarachnoid space
- release if bacterial cell wall components
Describe the development pathogenesis of meningitis
- release if bacterial cell wall component
- macrophages release cytokines
- subarachnoid space inflammation
- increase CSF outflow resistance
- cerebral vasculitis
- blood brain permiabilitt
- brain edema
- confusion and coma
Do you treat meningitis empirically
Absolutely!! Rapidly progressing !!
How is menigitis diagnosed
Cloudy cerebral spinal fluid jncreased white cells, high protein, low glucose
Can be seen on gram stain (may be negative is empirically treated)
Csf cukture for bacteria (pcr may be used)
How is viral meningitis disgnosed
Using PCR
How is chronic meningitis diagnosed
Test for specific agents
How soon should a suspected meningitis case be treated
Less than an hour After arriving at ER
How is menigitis treated
Ceftrixalone/vancomycin AND ampicillin for at risk groups when empiracally treated
Usually single antibiotic after cause determined
How is S. Pneumoniae meningitis treated
Third generation cephalosporin (ceftriaxone) vancomycin if resistance
How is neisseria menigitidis and haemophilus influenzae menigitis treated
Third generation cephalosporin CEFTRIAXONE
How is listeria meningitis treated?
Ampicillin
Resistant to all cephalosporins
Describe HPV
Caused by human papillomaviruses
Some serotypes are causative agents of cancers
Transmission by sexual contact
What are some consequences of HPV
Cancers (cervical,anal,oral)
Skin growths on genitalia, perianal area (usually transient infection resolving in months)
How are genital warts removed
Chemical means, freezing or surgery if necessary
