Bugs: Chlamydia and Mycoplasma Flashcards
Chlamydia: name the species that are pathogenic to humans the their general clinical manifestations?
What zoonotic organism can also infect humans?
What’s unique about the genome?
C. trachomatis – ocular and sexually transmitted;
C. pneumonia – respiratory
C. psittaci - avian
Genome: highly conserved and small
Describe the laboratory / biochemical findings of chlamydia ?
where is it found?
- Gram Negative
- Obligate Intracellular
- Ubiquitous in humans and animals
Describe the life cycle of chlamydia ?
Elementary Bodies - dense cell with compacted DNA, taken up via vacuole (inclusion body)
EB differentiates into Reticulate Bodies (RB)
Growth and replication of RBs on the inner membrane of the inclusion body
24 hours post infection: Differentiation back to EBs until they fill the inclusion body and the vacuole occupies much of the cytosol
38 hours post infection: Cell lysis and dispersion of EBs
Differences between EBs and RBs
Describe some Virulence factors of Chlamydia
- what is the important
EB: Condensed; function as spore; loss of water; late form is highly infections.
Histones to compact the DNA
RBs - Larger, non infectious; Decondensed; No Histones; Make own ATP
Virulence:
Type 3 secretions (cellular syringe; direct transfer of effector proteins from bug to host)
Effector Proteins: change cell signaling, cytoskeleton function
Adherence: -
Cytotoxins:
Use of cellular metabolites from host
Disease Manifestations of C. trachomatis
Ocular Chlamydia Trachomatis
Ocular Infection of the Newborn
Genital Chlamydia Trachomatis
Ocular infection of the Newborn:
- how is it contracted
- how is it treated
Neonates can contract C. trachomatis in the birth canal during deliver
Treat: Erythromycin eye drops
back up: macrolides
§ Ocular Chlamydia Trachomatis
- primary infection
- Chronic infection
- Describe the progression of the disease (what are the stages)
- End stage complication
- Primary infection: Inclusion Conjunctivitis; acute inflammatory response
- Chronic infection: Trachoma which can lead to blindness:
Stages:
Follicular conjunctivitis: DTH
Pannus: corneal inflammation and scarring
Trichiasis: Scarring contracts the conjunctiva; eyelashes inwards; abrasions to the cornea
Blindness
Genital Chlamydia Trachomatis
- Epidemiology:
- Symptoms:
- Female sequelae
Immunity
EPI: More cases of Chlamydia infection are reported to the CDC every year than all other infectious diseases combined: estimated 2.8M yearly
Most cases are asymptomatic or weakly symptomatic
Sexually active reservoirs of disease
Females: PID, Ectopic pregnancy, infertility
Immunity: antibody and cell mediated but short lived
Chlamydia Pneumoniae:
- manifestatons of Chronic infection:
- manifestations of disseminated chronic infection:
- what extra-pulmonary manifestation is it most associated with
- Treatment:
Sequelae of chronic infection: Chronic bronchitis, asthma, COPD
Disseminated infection:
Arthritis, AAA, stroke, MS
Strongest association with: Atherosclerosis and CVD
- can grow in atherosclerotic plaques
What is the treatment for Chlamydia Pneumonia?
an Atypical Pneumonia: 10-14 day course of □ Doxycycline □ Erythrocycline □ Quinolones
Avian Chlamydia psittaci:
- disease
- transmission
- Risk factors
- Diagnosis
- Treatment:
Psittacosis
Transmitted – acquired from EB In bird feces of infected animals
Risk Factors: people who work with birds, poultry, even people who work with telephone wires
§ High Mortality rate
Dx: History of bird exposure
Tx: Doxycycline, tetracycline (tx for atypicals)
Characteristics and Classification of Mycoplasma:
- from what gram type did they evolve?
- what’s unique about them?
- whats unique about the genome?
- whats unique about the morphology/culture?
- What unique requirement do they have?
- Evolved from Gram positives
- have lost their cell wall (therefore no beta lactam will affect them)
- Lots of genetic variation
- Morphology: Pleiomorphic; “fried egg morphology” except for M. pna “mulberry’
- Hard to manipulate in vivo
- Require acquisition of cholesterol from the host cell
What 5 species of mycoplasma are pathogenic to humans?
what diseases manifest from which species?
which are part of the commensal flora?
○ Mycoplasma pneumoniae - PNA
○ Mycoplasma hominis - STI -
○ Mycoplasma genitalium - STI
○ Ureaplasma urealyticum - STI
Mycoplasma fermentens -- associated with HIV
Normal Flora:
M. Hominins, M Genitalium. U. Urealyticum
M. Pneumoniae: atypical PNA
Symptoms
Dx
Aka “walking PNA”
○ M. Pneumonia
§ Cough, maliase, fever,
§ Community Acquired PNA
Dx:
Serology and PCR — good sensitivity
Cold agglutinins – but this has poor sensitivity
IgG or IgM by ELISA
Tx of Mycoplasma
Atypical Bacteria: ○ Tetracyclin: Doxycylcin ○ Quinolones: Ciproflaxin, Levoflaxin ○ Macrolides: Erythro, Azithro ○
