Flashcards in Chlamydia/Mycoplasma/Legionella Deck (32)
Chlamydia trachomatis diseases
Eye Trachoma/Neonatal Conjunctivitis/Genital Tract Infection
Chlamydia pneumoniae diseases
Respiratory Illness - atypical pneumonia
Chlamydia psittaci diseases
Zoonosis from birds that presents as a mild influenzal disease, but can develop into a rapidly severe and fatal pneumonia
Mycoplasma pneumoniae diseases
Tracheobronchitis manifested by headache, fever, and malaise, followed 2 – 4 days later by cough
Pontiac Fever–febrileinfluenza-likeillness without respiratory component
Legionellosis (severe pneumonia)
What are the various forms of chlamydia in its life cycle?
Elementary Body - infectious form that is uptaken into the cell via a phagosome
Reticulate Body - this is the reorganized EB after it enters the cell and it divides by binary fission until the entire cell is filled with the organisms
What is the major virulence factor of Chlamydia?
Heat Shock Proteins that provokes a potent inflammatory response causing tissue damage, and is the major virulence factor identified.
What is the major virulence factor of Mycoplasma?
M. Pneumonia attaches to cilia and microvilli lining of bronchial epithelium mediated by cytoadhesion protein called P1. The binding results in a coupling with oligosaccharide receptors, and interferes with ciliary action. An inflammatory response follows similar to that of a superantigen, resulting in desquamation, with resulting infiltration of lymphocytes and plasma cells resulting in thickened walls of bronchial tree.
Are Chlamydia intracellular or extracellular bacteria?
Obligate Intracellular bacteria
What is the the energy source of Chlamydia?
They are host cell dependent for energy as they produce no ATP
What are the manifestations of eye trachoma?
Chronic follicular conjunctivitis, eyelid curling and scarring
What immunotypes of C. trachomatis causes trachoma?
A through C
What immunotypes of C. trachomatis causes genital tract infection?
D through K
What are the manifestations of C. trachomatis genital tract infection?
• Urethritis (males), may be relatively assymp
• Epidymitis, prostatitis (less than 35 yr)
• cervicitis , usually assymptomatic
– salpingitis, PID ; high association with infertility
How does C. trachromatis cause infant conjunctivitis?
Contact with vaginal secretions during birth
Most common cause of neonatal conjunctivitis in U.S.
What immunotypes of C. trachomatis cause infant conjunctivitis?
D through K
The same as that cause genital tract infection
What other infection in neonates is C. trachomatis associated with?
What immunotype of C. trachomatis is associated with lymphogranuloma venereum?
L1, L2 and L3
What is a common cause of community pneumonia?
What is the reservoir of C. psittaci?
Birds like parrots and parakeets
What is the main infection of C. psittaci?
Lower respiratory tract infection
What is the appearance of M. pneumoniae on cell culture like?
What is the pathogenesis of M. pneumoniae?
– smallest organisms that replicate on complex cell free medium
– no cell wall, single triple layered membrane (sterols), requires cholesterol for growth
– divides by binary fission
– fried egg appearance on culture after days
– binds oligosaccharide receptors- adhesion P1
What are some other diseases that Mycoplasma may cause?
What is characteristic about the CXR of Mycoplasma infections?
They will be out of proportion with the severity of the infection
What Gram is Legionella?
Gram negative. But they do not stain clinically
What is the aerobic status of Legionella?
• Obligate aerobe
Are Legionella catalase positive or negative?
What is the reservoir of Legionella?
• Lives in water
– Aquatic lakes
– Amplified in man made reservoirs
• Enhanced by warm temperature, stagnation, scale, sediment and commensal algae, protozoa and bacteria
What is the pathogenesis of Legionella?
• OMP (porin) binds C3b complement receptor on mononuclear phagocytes
• Endocytosis inhibit phagolysosome fusion leading to intracellular multiplication
• Kill cell with lysis of vacuole
What are the main clinical manifestations of Legionella infection?
Short Incubation • Pontiac Fever–febrile influenza-like illness without respiratory component
Long Incubation • Legionellosis (severe pneumonia)