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3 most common causes of CA-pneumonia
- Streptococcus pneumoniae
- Haemophilus influenzae
- Staphylococcus aureus
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Name other causes of CA-pneumonia besides 3 most common.
- Mycoplasma pneumoniae
- Chlamydophila pneumoniae
- Viruses
- Aspiration
- Gram-N bacillus
- Legionella species
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Mycoplasma and Ureaplasma
- Smallest free-living bacteria
- lack a cell wall
- facultative anaerobes (M. pneumoniae is a strict anaerobe)
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Smallest free-living bacteria
Mycoplasma and Ureaplasma
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Which genus lacks cell walls and are thus pleomorphic? They are also not stainable.
Mycoplasma
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Mycoplasma have no cell wall, but their cell membranes contain
sterols (obtained from exogenous media)
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4 Mycoplasma Diseases
- Mycoplasma pneumoniae
- M. hominis- pyelonephritis, salpingititis, post-partum fever, peripartum sepsis, neonatal conjunctivitis
- M. genitalium- non-gonococcal urethritis
- Ureaplasma urealyticum- endometriosis
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Transmission of mycoplasma pneumoniae
aerosols
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Virulence factor of Atypical or Mycoplasma Pneumoniae
P1 Adhesion protein (binds sialic-rich glycoproteins)
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Pathogenesis of M. pneumoniae
- Remains extracellular
- Binds to respiratory ciliated epithelium via P1 protein
- Adhesion >> ciliostasis >> cell destruction
- loss of ciliated cells >> reduced ciliated clearance
- Bacteria gain entrance to lower respiratory tract
- Persistent non-productive cough
- Usually self-limited and non-fatal
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Ciliostasis
Reduction in number of cilia per cell. Seen in M. pneumoniae.
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M. pneumoniae causes upper or lower respiratory infections?
Both, but upper is more common
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Tracheobronchitis
Bronchial passages infiltrated with lymphocytes and plasma cells, seen in M. pneumoniae
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Mycoplasma Pneumoniae results in what type of immunity?
Incomplete immunity, secondary infections are common
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Mucocutaneous eruptions can be caused by
M pneumoniae
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Oral ulceration with skin rash and conjunctivitis. Tx?
Stevens-Johnson Syndrome, associated with M. pneumoniae
Tx= Corticosteroids
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Tx of Mycoplasmas
- Azithromycin, doxycycline, or levofloxacin
- Clindamycin used for M. hominis, M. gentalium
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Chlamydiaceae: ]
Intracellular?
Visible on Gram-stain?
- Obligate intracellular bacteria
- NOT visible on gram stain, lacks peptidoglycan (don't treat with penicillins, cephalosporins, vancomycin or other cell wall active antibiotics). Has lipopolysaccharide between outer membranes.
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Which bacteria would you not want to treat with cell wall active antibiotics? Why?
- Chlamydiaceae
- Lack peptidoglycan of typical cell wall
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2 Distinct morphologic forms of Chlamydiaceae
- Elementary Body (EB)- small, infectious
- Reticulate Body (RB)-larger, non-infectious
Not cultured in routine laboratory media-grown in tissues
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Which form of Chlamydiaceae is an intracytoplasmic includsion body?
Elementary body
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Which form of Chlamydiaceae is the metabolically active, replicating form?
Reticuluate body
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Pathogenesis of Chlamydia trachomatis
- EB accumulate and rupture cells, infect adjacent cells
- No long-lasting immunity (like Mycoplasma)
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Chlamydia trachomatis can cause? (other than genito stuff)
Eye infections and blindness
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Chronic inflammatory condition of the ocular and palpebral conjunctiva and cornea in a setting of poor hygiene and crowding. Watery discharge, flies can carry this. Can lead to blindness after multipel re-exposures.
Trachoma (Chlamydia trachomatis)
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Which organism uses the SAFE Strategy for prevention? What is the SAFE strategy?
- Chlamydia trachomatis prevention
- Surgery, Antibiotics, Face washing, Environmental change (better sanitation)
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Important cause of bronchitis, pneumonia, and sinusitis that is generally asymptomatic, but more severe in adults
Chlamydophila pneumoniae
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Neonate exposure to ____ through the mother's service and can result in Perinatal Conjunctivitis
C. trachomatis
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Diagnosis of these organisms requires tissue culture.
Tx of these organisms?
- N. gonorrhoeae
- H. influenzae
- S. pneumoniae or HSV
Tx: Azithromycin or doxycycline
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Initial presentation of upper respiratory tract infection followed by bronchitis or pneumonia with rhonchi or rales
Chlamydophila pneumoniae
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"Parrot Fever" (Psittacosis or Ornithosis) causative agent?
Chlamydophila psittaci
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Reservoir of Chlamydophila psittaci? Transmission? Common among?
- Birds (parrot fever, ornithosis)
- Transmission via inhalation of dried bird feces, urine, and respiratory secretions
- Common among pet shop workers, poulty-processing plant workers
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Tx of Chlamydophila psittaci
Doxycycline
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Diagnose Chlamydophila psitacci with
IFA or CF
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Thin, helical, Gram-N, mostly ANAEROBIC bacteria
Motile (corkscrew motion)
Not visible with conventional light microscopy, must use dark-field microscopy
Spirochetes
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3 Spirochete Disease Agents
- Treponema (Venereal syphilis)
- Borrelia (Lyme disease)
- Leptospira (Leptospirosis)
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Causative agent of Venereal syphilis (STD)?
T. pallidum pallidum (Treponema; spirochete)
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Nonvenereal Treponemal Infections (3)
- Yaws (warm humid tropical areas)- children
- Bejel (desert areas)- children
- Pinta (tropical areas)- young adults
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How are Yaw, Bejel, and Pinta (nonvenereal treponemal infections) spread?
Spread person-to-person by direct contact
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Yaws, Bejel, or Pinta: Small puritic papules that enlarge and persist for years, disseminated and recurrent within 3-9 months. Become pigmented with age. Skin is ONLY organ involved.
Pinta
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Yaws, Bejel, or Pinta: Leads to disfiguring pigment changes and scarring, skin has mottled appearance
Pinta
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Yaws, Bejel, or Pinta: Primarily oral lesions, can have gummas
Bejel
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Yaws, Bejel, or Pinta: Initial lesion becomes a large papilloma, secondary disease produces multiple cutaneous lesions, tertiary stage produces bone and joint deformities
Yaws
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Treatment of Novenereal Treponemal Infections
- Penicillin G (IM)
- Oral doxycycline, tetracycline, or erythromycin
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Thin, coiled, Gram-N, aerobic, motile, hooked ends w/ paired axial flagella (burrow into tissue)
Leptospira interrogans or biflexa
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Contact with water, food, or soil containing rodent urine increases risk for?
Leptospira interrogans or biflexa
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Influenza-like symptoms with conjunctival suffusion, recovery when opsoniziing IG induces immune clearance
Clinical Leptospirosis
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Severe disseminated disease (multi-organ involvement) w/ high fever (>104F), Vascular collapse, Severe pulmonary hemorrhagic, etc.
Weil Syndrome (Leptospira interrogans)
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Leptospirosis diagnosis and tx?
- Diagnosis: Serology, ELISA, PCR, culture
- Tx: Doxycycline, amoxicillin
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