Exam 3 Fastidious, Intracellular, Other Flashcards
Respiratory disease-causing bacteria
- Corynebacterium diphtheriae
- Bordatella pertussis
- Haemophilus influenzae
- Legionella pneumophila
- Mycoplasma pneumonia
Meningitis-causing bacteria
Listeria monocytogenes
STD bacteria
Chlamydia trachomatis
Zoonotic disease causing bacteria
- Francisella tularensis
- Rickettsia ricketsii
C. diphtheria has ____ growth on what agar?
aerobic; Loeffler’s agar or Tisdale’s (tellurite) agar
How is diphtheria transmitted?
Aerosol, human to human
youbreathe it out
Diphtheria causes disease in what part of the body?
Upper respiratory tract or skin
Where does C. diphtheria colonize?
Nasopharynx or adjacent regions
____ is responsible for the severe symptoms of diphtheria
Prophage-coded diphtheria toxin
Diphtheria causes a ____ in the back of the throat which can lead to _____
Thick covering; respiratory obstruction and myocarditis
Diphtheria - thick covering in the back of the throat presents as:
Pharyngitis with grayish adherent pseudomembrane
Diphtheria can lead to ____ damage
- kidney
- heart
- nerve
Diphtheria toxin is a phage tox gene produced by:
Lysogenized strains
Diphtheria toxin structure
A-B toxin
Diphtheria toxin blocks:
Protein synthesis
____ inhibits transcription of diphtheria toxin operon
Iron (corepressor)
Excess iron represses toxin production
A subunit of AB toxin - function
- Possesses catalytic activity
- inactivates elongation factor 2 (EF-2), prevents protein synthesis by ribosome
B subunit of AB toxin - function
Corynebacterium diphtheria
Membrane binding region
Diphtheria treatment
- DOC penicillin
- anti toxin
Prevention of diphtheria
Toxoid vaccine (DTAP)
True or false: diphtheria is rare in the US
True - due to effective vaccine
Diphtheria toxin is inactivated by:
Heat or chemical
Diphtheria is a _____ disease
Reportable (by law)
Bordatella pertussis classification
Gram negative coccobacillus
Bordatella pertussis causes:
Whooping cough
Bordatella pertussis invades what cells?
Alveolar macrophages
Bordatella pertussis is aerobic/nonaerobic
Strict aerobe
Whooping cough is described as:
- uncontrollable violent coughing
- hard to breathe
Whooping cough is highly _____. _____ are at greatest risk
Communicable; Children less than a year old
Whooping cough is endemic in the:
US
Whooping cough mortality before vaccination
21-31%
Bordatella pertussis virulence factors
- Adhesins (FHA)
- 2 distinct toxins (pertussis toxin, tracheal cytotoxin)
Bordatella pertussis adhesins
- filamentous hemagglutinin (FHA)
- pertactin
- fimbriae
____ is a major colonizing factor in nasopharynx
Bordatella pertussis
FHA
Bordatella pertussis
Pertussis toxin is secreted by ____
Type IV secretion system
Pertussis toxin function
increases mucus, leading to cough
Tracheal cytotoxin function
- damages respiratory tissues and paralyzes cilia
- leads to stagnant mucus and prevention of pathogen removal
- damage leads to paroxysmal cough
Tracheal cytotoxin damage leads to
Paroxysmal cough (whooping cough)
Bordatella pertussis - pertussis toxin pathogenesis
- AB toxin binds to ciliated respiratory cells
- unregulated activation of adenylate cyclase leads to increase in cAMP, increasing signal transduction
- increase in respiratory secretions and mucus
- mucus leads to coughing
Tracheal cytotoxin causes inflammation and ciliostasis to interfere with:
Secretions clearance
Where does Bordatella pertussis colonize?
Trachea - attach to cilia of respiratory epithelial cells
True or false: If you have whooping cough, you are most contagious during the paroxysmal (coughing) phase
False - you are more contagious (higher bacterial culture) during the catarrhal phase
More infectious before the cough starts
Bordatella pertussis diagnosis
PCR
Can culture but is is much slower
Bordatella pertussis DOC
Erythromycin
Whooping cough incidence is highest in ____ since 1955
2012
Decrease in whooping cough due to
DTAP vaccine
DTAP/Tdap vaccine contains ____ to stimulate immune response to toxin
inactivated tetanus toxin
Tdap must be given to all:
Pregnant women (between weeks 27-36)
H. influenza main virulence factor
- PRP capsule (antiphagocytic)
- Also has IgA protease and endotoxin
PRP capsule stands for:
Phosphoribosylribitol phosphate
Most serious serotype of H. flu
Type b (Hib)
H. influenzae grows as satellite colonies around:
S. aureus (secretes required growth factors - X factor and V factor)
H. influenzae causes major diseases among
Infants and elderly
H. influenzae infection can cause:
- epiglottitis (can be life threatening)
- meningitis (before vaccines)
- bacteremia
Before vaccines, H. flu meningitis was a major cause of:
90% of meningitis in children 6 months - 2 years
H. influenzae treatment
Broad spectrum antibiotics (cephalosporins, azithromycin)
Ampicillin resistant strains are common in _____ and conferred by ____
H. influenza; plasmid
True or false: there is no vaccine for H. influenzae
False - conjugate vaccine (PRP-tetanus toxoid) is very effective
H. flu ____ vaccine is poorly immunogenic
PRP capsule polysaccharide
When is H. flu vaccine administered?
- 2, 4, 6 months
- booster at 12 months
____ vaccine is T dependent, efficient, has good memory
Conjugate
True or false: H. influenzae cases have decreased
True due to effective Hib vaccine
< 1 case/100,000 children under 5 years of age
H. influenzae primarily affects:
unvaccinated/incompletely vaccinated children
H. influenzae and H. aegyptius can both cause:
Bacterial conjunctivitis
Legionella pneumophila killed 34 at:
American Legion convention in Philadelphia (1976)
Legionella pneumophila is fastidious - it is best seen with:
Silver stains
_______ is facultative intracellular
Legionella pneumophila
_____ causes 90% of legionellosis in US
Legionella pneumophila
Legionella pneumophila inhabits _____ environments
Aquatic
Legionella pneumophila is transmitted by:
inhalation of aerosolized bacteria
True or false: Legionella pneumophila can be spread person to person
False - is not spread person to person
Legionella pneumophila produces:
Beta lactamase
Legionellosis: types of disease
- pontiac fever
- Legionnaire’s disease (pneumonia)
Pontiac fever is a milder form of _____. It is characterized by acute ____ with no _____
legionellosis; flu-like syndrome; no lung involvement
Pontiac fever is usually ____ with good prognosis
Self-limiting
Legionnaire’s disease incubation time
2-10 days
Legionnaire’s disease causes pneumonia that can lead to:
Septic shock and kidney failure
Major predisposing factors to getting Legionnaire’s disease
- chronic lung diseases
- smoking
- older males
Legionnaire’s disease symptoms
- fever
- chills
- headache
- cough
- diarrhea
- changes in mental status
Legionella pneumophila clinical presentation
Lower lobe filled with fluid, obscuration of hemidiaphragm silhouette
Smallest free living organisms
Mycoplasmas
____ lack a cell wall so they do not gram stain
Mycoplasmas
Mycoplasma cell membranes contain:
Sterols (modified steroid)
Which type of bacteria forms fried egg colonies?
Mycoplasmas
True or false: Mycoplasma pneumoniae is not as deadly as other pneumonia-causing bacteria
True
Mycoplasma pneumoniae causes ____ in 70-80% of infections
Tracheobronchitis
Mycoplasma pneumoniae causes ____ in 10% of infections
Walking pneumonia
Mycoplasma pneumoniae causes pneumonia in what age groups?
Teens and young adults
Walking pneumonia is also called:
Atypical pneumonia
True or false: walking pneumonia has a severe disease but short duration
False - mild disease but long duration
Walking pneumonia is characterized by what kind of cough?
Persistent, non productive
Walking pneumonia presentation on xray
Patchy lower lobe
Walking pneumonia is ____ fatal
Rarely
Recommended method of diagnosis for Mycoplasma pneumoniae
PCR (amplify its genes)
_____ not recommended for diagnosis of Mycoplasma pneumoniae
Cold agglutins (does not work at body temp - only lower temps 4 degrees C)
M. genitalium causes:
Non-gonococcal urethritis (NGU)
How is M. genitalium transmitted?
Sexually
Mycoplasma hominis causes:
Pyelonephritis
Ureaplasma urealyticum causes:
- NGU
- Pyelonephritis
Mycoplasmas should be treated with:
Tetracyclines
____ grows well at 5-40 degrees celsius
Listeria monocytogenes
Listeria monocytogenes has a tropism for:
Fetus and placenta of most animals
Listeria outbreak usually occurs in:
Ready to eat meat and cheese
Listeria monocytogenes causes opportunistic infection in:
- Neonates
- Immunocompromised adults
- pregnant women
- diabetics
Transmission - Listeria can cross:
- intestine (processed meat products)
- placenta
- blood brain barrier
Listeriosis is often ____ in healthy adults
Asymptomatic
Clinical forms of Listeriosis
- Non-invasive
- Invasive
Non-invasive listeriosis can cause:
gastroenteritis
Invasive listeriosis can cause:
meningitis in neonates and older adults
________ is the leading cause of meningitis in cancer and renal transplant patients
Listeria monocytogenes
Listeria monocytogenes can be found in
CSF (facultative intracellular in monocytes, macrophages, and PMN)
remember, it causes meningitis so makes sense it is in CSF
14% of listerosis cases occurs in:
pregnant women
transplacental transmission results in miscarriage or stillbirth
Neonates can contract listeriosis at ___ and often causes ____
birth; meningitis (CNS most often affected)
What diseases can be caused by Chlamydia trachomatis?
- Chlamydia (sexually transmitted)
- ocular diseases
- lymphogranuloma venereum
Chlamydophila pneumoniae causes:
Bronchopneumonia
____ is clinically similar to Mycoplasma pneumonia
Chlamydophila pneumoniae
____ is linked to arteriosclerosis
Chlamydophila pneumoniae
Chlamydiaceae life cycle
- Elementary bodies attach to cell receptors and gets internalized
- Reticulate bodies (replicating form) form inclusion bodies; binary fission
- Replication results in death of the cell (releases infectious EB)
Most commonly reported notifiable disease in the US
Chlamydia trachomatis
Most common bacterial STD in the US
Chlamydia trachomatis
Local Chlamydia trachomatis infection in men causes:
- conjunctivitis
- urethritis
Local Chlamydia trachomatis infection in women causes:
- conjunctivitis
- urethritis
- cervicitis
Infants infected with Chlamydia trachomatis can get infection of the conjunctiva known as:
Ophthalmia neonaturum (can cause blindness)
___ can experience sequelae from chlamydia infection, which include:
Women; infertility, ectopic pregnancy, chronic pelvic pain
_____ causes 15-40% of urethritis cases in the US
Chlamydia trachomatis
Trachoma
Chronic keratoconjunctivitis
Symptoms of trachoma
- cornea and conjunctiva inflammation
- inflamed granulation of inner surface of eyelids
Leading cause of preventable blindness globally
Trachoma
Trachoma is rare in:
developed countries (prevented by antibiotics)
Perinatal transmission of Chlamydia trachomatis to infant can result in infections of the:
- conjunctiva
- respiratory tract
- pneumonia
Children older than 1 year with signs of Chlamydia trachomatis serves as possible evidence of
Sexual abuse
Pap smear with cervicitis showing inclusion bodies indicates ____ infection
Chlamydia trachomatis
Venereal disease
lymphogranuloma venerum caused by Chlamydia trachomatis
Stages of venereal disease
First stage: small painless vesicular lesion at infection site
Second stage: 2-6 weeks later; regional lymphadenopathy, draining buboes
sexually transmitted
Diagnosis of Chlamydia trachomatis
PCR
If a patient has chlamydia, also check for:
Gonorrhea
DOC for Chlamydia trachomatis
tetracyclines
Francisella tularensis causes ____ disease, also known as:
zoonotic; tularemia/rabbit fever
____ has many animal reservoirs
Francisella tularensis
____ has been weaponized and is referred to as Select Agent Tier 1
Francisella tularensis
_____ is highly infectious and can be used as a biological weapon
Francisella tularensis
Major clinical manifestations of tularemia
- acute pneumonia
- skin ulcers
- lymphadenopathy
Francisella tularensis acute pneumonia has ____ fatality
30-80%
____ reservoir is in cats (infects through bite or scratch)
Bartonella henselae
Cat Scratch Disease causes:
- chronic regional lymphadenopathy in children
- pustular lesion at scratch site
- spreads to adjacent lymph nodes
- fever. malaise
- disseminates to spleen, joints, CNS
Bacillary angiomatosis occurs in patients who have ____ due to infection via ____
late stage AIDS; Bartonella henselae
Bartonella henselae DOC
Azithromycin
Zoonotic infection by pasteurella multocida is often due to _____
cat or dog scratch, bite, lick
Pasteurella multocida often causes:
Cellulitis
Rocky mountain spotted fever is caused by
Rickettsia rickettsii
Most common rickettsial pathogen in the US
Rickettsia rickettsii
Typhus fever forms of Rickettsiaceae
- Rickettsia prowazekii
- Rickettsia typhi
both now rare
Rickettsia rickettsii infects you via:
Infected ticks
Rickettsia rickettsii causes:
- Vasculitis (leakage from blood vessels)
- hypovolemia (decreased blood plasma)
- poor blood flow to organs
Most common rickettsial infection in the US
Rickettsia rickettsii
Most common vector-borne infection in the US
Rickettsia rickettsii
What tick is the most common source of Rickettsia rickettsii?
American dog tick (Eastern US)
Which tick is most commonly found in western parts of US?
Rocky mountain wood tick
There is an estimated ____ cases per year of Rocky Mountain Spotted Fever, but only ____ cases were reported
300,000; 30,000
Symptoms of Rocky Mountain Spotted fever
- Severe myalgia
- high fever
- headache
- rash (including palms and soles)
- cough
- confusion, ataxia
Mortality is ____ in Rocky Mountain Spotted fever if untreated
35%
Diagnosis of Rickettsia rickettsii
- Serology (antibodies produced late, < 8 weeks)
- Microimmunofluorescence assay (IFA) test for IgM, IgG
- Skin biopsy (staining)
Rickettsia rickettsii DOC
Tetracyclines (can reduce mortality to 5%)
How to remove tick
- Tweezers and pull upward with steady even pressure
- do not set tick on fire
- keep tick for 3 weeks for ID