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PHARM/MHD EXAM - 3 > L12 MHD: Chlamydia/Mycoplasma/Legionella > Flashcards

L12 MHD: Chlamydia/Mycoplasma/Legionella Flashcards

1
Q

Chlamydia General Features

  1. ________ _______ Bacteria (needs to use host’s ATP)
  2. Nucleic acid content?
  3. Cell membrane lacks what structure?
  4. Gram stain?
  5. Giemsa stain- what color do elementary bodies stain? What color to reticular bodies stain?
  6. Penicillin sensitive or resistant?
A
  1. Obligate Intracellular Bacteria
    - Host cell dependent for energy
    - Produces no ATP (unlike Rickettsia which can eventually start making its own ATP)
    - Derives energy in the endosome (ADP exchanged for ATP)
  2. Contains DNA & RNA
  3. Lacks peptidoglycan layer
  4. Gram stain- negative or variable- not used
  5. Giemsa Stain:
    - EB: purple
    - RB: blue
  6. Penicillin resistant
    - Although cell wall contains PBP, penicillin is not clinically effective
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2
Q

Describe the 5 steps of the Chlamydia lifecycle.

What two forms can Chlamydia exist?

A
  1. Elementary body (EB) attaches and enters cells (usually columnar epithelial) via endocytosis
  2. Fusion with lysosome is prevented and EB reorganize into Reticular bodies (RB)
  3. Multiplication of RBs via binary fission
  4. Reorganization of RBs into EBs
  5. Release of EBs, which go on to infect more cells
  • EBs are the infectious form*
  • Small & dense
  • RBs are the form seen on tissues*
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3
Q

Chlamydiaceae - what are the 3 species?

A
  1. Chlamydiae Trachomatis
  2. Chlamydiae Psittaci
  3. Chlamydiae Pneumoniae
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4
Q

How does Chlamydia get into the cell and what does it induce?

A

Gains access through minor abrasions, produces significant cell damage and a severe inflammatory response

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5
Q

C. trachomatis - Serotypes A,B,C

  1. What does Trachoma of the A, B, C serotype group cause?
  2. Where is this commonly seen?
  3. How is it treated?
  4. How is it prevented?
A
  1. Chronic Follicular Conjunctivitis, eyelid curling and scarring- major cause of preventable blindness worldwide due to increased vascularization/scarring
  2. Seen in underdeveloped countries (Africa, Asia, Mediterranean)
  3. Treated with surgery, tetracycline 1% ointment, or azithromycin
  4. Prevented by improved hygiene standards

C. Trachomatis A/B/C–>Africa/ Blindness/Chronic infection

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6
Q

C. Trachomatis- Genital Infection

  1. Caused by what serotypes?
  2. Who is most likely to get this disease? What is the incubation period?
  3. What is the most common sign seen in men? Men under 35 may have what clinical symptoms?
  4. What is the most common sign in women? What are the consequences of infection?
  5. How can infants be affected?
A
  1. Serotypes D-K
  2. Sexually active teenagers
    - High rate of transmission
    - 2-6 wk incubation
  3. Males: may be relatively asymptomatic
    - Urethritis
    - Under 35: epidymitis, prostatitis
  4. Females: usually asymptomatic
    - Cervicitis
    - May lead to: salpingitis, PID
    - If untreated, high association with infertility
  5. Infants can get pneumonia (acquired from passage through infected birth canal)
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7
Q

Inclusion Conjunctivitis

  1. Affects what age group the most?
  2. How is it acquired?
  3. What C. Trachomatis serotypes cause it?
  4. Clinical sign after birth?
  5. Dx?
  6. Treatment?
A
  1. Mostly affects neonates
    - Most common cause of neonatal conjunctivitis in the US
    - Can also occur in adults
  2. Acquired through vaginal secretions
  3. Serotypes D-K
  4. Mucopurulent eye discharge
    - 2-25% after birth
  5. Dx: inclusions demonstrated or by culture
  6. Treatment: Tetracycline
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8
Q

Chlamydia trachomatis - Neonatal Pneumonia

  1. Serotypes?
  2. How long after birth does it take for pneumonia to develop?
  3. What other symptom is it seen with?
  4. What are two clinical symptoms?
A
  1. D-K
  2. 2-12 weeks after birth
  3. Inclusion Conjunctivitis
  4. Tachypnea (rapid breathing), paroxysmal cough (staccato cough- comes as a series of outbursts with time for at least one breath in between each cough)
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9
Q
  1. Serotypes L1, L2, L3 of Chlamydia Trachomatis cause what disease?
  2. Where is this commonly seen?
  3. Clinical presentation?
  4. What diagnostic test is helpful?
  5. How is disease treated?
A
  1. Lymphogranuloma Venereum
  2. South America & Africa
  3. Suppurative multilocular inguinal lymph nodes (bubos)
    - Fistula drainage
    - Structures (urethra, rectal)
    - Perirectal abscess
  4. Serology helpful in LGV (1:64)
  5. Tetracycline/Erythromycin
    - 3 week course
    - may not influence ulcerations- drainage may be necessary
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10
Q

Chlamydia Trachomatis Dx
1. Where do you get cell culture from?

  1. What are 3 non-culture tests you can do to diagnose?
    a)
    b)
    c)
  2. Serology is useful for what serotype?
A
  1. Epithelial scrapings
    - Used to isolate organism
  2. Non-Culture
    a) Direct Fluorescent Ab (DFA)- Ab against elementary bodies’ major outer membrane protein- 80-90% sensitive, 99% specific
    b) Lipopolysaccharide Enzyme Assays
    c) DNA Probe of RIBOSOMAL RNA Sensitivity- 85%, Specificity- 99%
  3. Serology helpful in LGV (1:64)
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11
Q

Chlamydia trachomatis Treatment

  1. What 4 classes of antibiotics can be used?
    - Examples?
  2. Which one only requires 1 dose?
  3. Which should be given to a pregnant patient?
A

1.

  • Tetracyclines*
  • Tetracycline 2g/d x 7days
  • Doxycycline 200g/d x 7 days
  • Quinolones*
  • Ofloxacin/Levaquin x 7 days
  • Azithromycin* 1g/d x 1 day
  • Erythromycin* 2g/d x 7 days
  1. Azithromycin only requires one dose and has a 95% cure rate
  2. Erythromycin is given to pregnant patients
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12
Q

C. pneumoniae

  1. Serotype?
  2. Causes what % of pneumonia/bronchitis?
  3. Clinical symptoms?
  4. Diagnosis?
  5. Treatment?
A
  1. Single serotype- TWAR
  2. 10% of pneumonia/bronchitis via respiratory spread
  3. Clinically pt may have:
    - pharyngitis
    - laryngitis
    - pneumonia (walking)
    - atherosclerosis (??)
  4. Serology would be the way to dx, rarely performed
  5. Treate with Tetracycline, erythromycin or fluoroquinolone for 10-14 days
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13
Q

C. psittaci

  1. What is the typical animal reservoir?
  2. Causes what type of infection?
  3. How is it diagnosed?
  4. Treatment?
A
  1. BIRDS (parrots, parakeets)
    - Inhalation of respiratory secretions or droppings of infected birds- enters lung and spreads via RE system
  2. Lower respiratory tract infection
  3. Dx- complement fixation (four fold increase in IgM > 1:16)
  4. Tetracycline or erythromycin can be used to treat
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14
Q

Mycoplasma pneumoniae

  1. Smallest organism to ___________ on complex cell free medium
  2. What is unique about its structure? What does it require to grow?
  3. Divides via?
  4. Appearance on culture?
A
  1. Smallest organism to replicate on complex cell free medium
  2. No cell wall, single triple layered membrane- requires cholesterol for growth
  3. Divides by binary fission
  4. Fried egg appearance, stained with fluorescent Abs
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15
Q

Epidemiology of Mycoplasma Pneumoniae

  1. How often do epidemics occur?
  2. Causes 5-15% of what type of pneumonia?
  3. Peak incidence in what age group?
  4. How is it spread? What is the incubation period?
A
  1. Every 4-7 years
  2. Community acquired pneumonia
  3. Peak incidence in teenagers (more common in patients
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16
Q

Mycoplasma Pneumoniae

  1. What are the clinical symptoms?
  2. What occurs in 25-50% of patients?
  3. What is unique about chest x-ray (CXR) finding
  4. Describe the cough associated with mycoplasma pneumoniae
A
  1. Headache, fever, chills
  2. 20-50% of patients will have chest pain, sore throat, myalgias and rhinorrhea
  3. X-ray looks worse than the patient- CXR findings out of proportion to clinical presentation/findings
  4. Non-productive cough, later, white/clear sputum
17
Q

What other diseases can Mycoplasma cause?

A 
-Dermatologic
Macular, morbilliform, E. nodosum rash
-Cardiac
Underestimated:  arrhythmia, CHF, EKG 
Mycocarditis, pericarditis
-Arthritis
-Neurologic
Guillain-Barre, transverse myelitis, meningoencephalitis (1:1000)
18
Q

What are 4 ways to diagnose Mycoplasma?

A
  1. CXR
    -may appear severe, interstitial pattern
    -not diagnostic
  2. Culture (10-14 days)
  3. Serology (high titer > 1:32)
    PCR
  4. Cold hemagglutinins- bind I Ag or erythrocytes @ 40C
    >1:128
    **High titer of cold agglutinins (IgM) which can agglutinate or lyse RBCs
19
Q

What three antibiotics are used to treat mycoplasma diseases?

A
  1. Macrolides
    - Erythromycin, Azithromycin, Clarithromycin
  2. Tetracyclines
  3. Fluoroquinolones

Penicillin is ineffective because Mycoplasma have no cell wall

20
Q

Mycoplasma hominus

  1. Common isolate in what disease?
  2. Cause of fever following what two procedures?
  3. What type of infection does it cause?
  4. How is it diagnosed?
  5. What can you give to treat it? What can’t be used?
A
  1. Bacterial vaginosis
  2. Cause of fever following abortion or post partum endometritis
  3. Opportunistic infection- joint, wound, CNS (neonates)
  4. Diagnos via mycoplasma broth
  5. Tx with tetracycline, clindamycin or chloramphenicol
    * *Do not use macrolides**
21
Q

Legionella

  1. Gram positive or negative?
  2. What stain do you use to see bacterium?
  3. 85% of all infections are caused by what species? What serotypes of this species?
A
  1. Slender gram-negative rods
  2. Seen in tissue with Dieterle’s Silver Stain
  3. 85% of infections caused by Legionella pneumophila - Serotypes 1-6
22
Q

Legionella: Cultural Characteristics

  1. Aerobe/anaerobe?
  2. Fermentation?
  3. Growth requirements?
  4. Motility?
  5. Catalase test?
  6. Oxidase test?
  7. Beta-lactamase (+)/(-)?
A
  1. Obligate aerobe
  2. Non-fermentative
    - Derive energy from amino acids
  3. Fastidious growth requirements
  4. Motile
  5. Catalase positive
  6. Weakly oxidase positive
  7. Beta-lactamase positive
23
Q
  1. Where does Legionella live?
  2. Where is community acquired typically found?
  3. How do outbreaks occur?
  4. What are host risk factors for the disease?
A
  1. The Water
    - aquatic lakes
    - amplified man made reservoirs
    - potable water (hot water systems)
  2. CA-Legionella- cooling towers, showers, grocery store mist, fountains, high pressure chambers, air conditioners, whirlpools, hotels (travel associated);
  3. Outbreaks occur as sporadic disease or as epidemics
    - Healthcare associated - 25%
  4. Risk factors: transplant recipients, cigarette smokers, chronic lung disease
24
Q

Pathogenesis of Legionella

  1. Route of entry?
  2. What happens after pathogen enters body?
  3. What type of immunity is required to kill the infection?
A
  1. Inhaled infectious aerosols
    -Shower, sink tap, cooling tower, humidifier
  2. OMP (porin) binds C3b complement receptor on mononuclear phagocytes- endocytosis–>inhibit phagolysosome fusion–>intracellular multiplication
    Kill cell with lysis of vacuole
  3. Immunity is cell mediate- requires sensitized T-cells to activate macrophages
25
Q

Clinical Manifestations of Legionella

  1. What is Pontiac Fever?
  2. What is Legionellosis?
  3. Are asymptomatic infections common?
A
  1. Pontiac Fever- self limited febrile influenza like illness without respiratory component
    - Short incubation 1-2 days
  2. Legionellosis (severe pneumonia)
    - Longer incubation 2-10 days
    - Multilobular pneumonia
    - Multisystem disease: GI, liver, kidney, CNS
    - 10-20% mortality
  3. Asymptomatic infection common
26
Q

Legionella: Laboratory Diagnosis

  1. What type of stain is used?
  2. What’s a low sensitivity test?
  3. Where is culture gathered from?
  4. What is the special media used for Legionella?
  5. Describe urinary antigen test
  6. What are two other tests that can be used?
A
  1. Tissue Dieterle Silver Stain
  2. Direct fluorescent antibody test
  3. Sputum- low yield; BAL, lung biopsy, pleural fluid, other body fluid/tissue
  4. Buffered charcoal yeast extract agar (BYCE) TEST
  5. Urinary antigen tests- utilizes ELISA to detect L. pneumophila serogroup 1 (60-90% sensitive- sensitivity increases with severity of disease)
  6. PCR & Serology tests (requires 4 fold rise in titer- 1:128)
27
Q

How is Legionella Treated?`

A

Antibiotics with intracellular activity required!

  • Macrolides: Erythromycin, Clarythromycin, Azithromycin (all work by inhibiting the bacterial ribosomal function at the 50S subunit)
  • Fluoroquinolones: ciprofloxacin and moxifloxacin can be used
28
Q

List three ways to prevent Legionella

A
  1. Eliminate or reduce numbers in water supply
  2. Clean reservoirs (air conditioning cooling towers)
  3. Remove from potable water systems
    - Superheating, hyperchlorination, copper/silver ionization
29
Q

Cold hemaglutinins are used to diagnose which bacteria?

A

Mycoplasma

30
Q

Legionella produces ____ which renders penicillins inactive

A

B - lactamases

PHARM/MHD EXAM - 3 (21 decks)

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