Chlamydia, Mycoplasma, and anaerobes Flashcards
What are the important features of chlamydiaceae?
Obligate intracellular parasites and as a result will not grow on agar or gram stain.
They have an outer membrane that is similar to gram negative bacteria
They do not appear to produce a peptidoglycan cell wall.
What species of chlamydiaceae infect humans?
Chlamydia trachomatis
Chlamydophila pneumoniae
Chlamydophila psittaci
What are the 15 strains of chlamydia trachomatis divided into?
2 biovars:
LGV biovar (3 subtypes)
Trachoma biovar
What kind of infection do LGV biovars cause?
STI called lymphogranuloma venereum
What kind of illnesses do tranchoma biovars of chlamydia trachomatis cause?
Serovars A, B, Ba and C cause occular trachoma
Serovars D - K cause sexually transmitted genital tract disease as well as inclusion conjunctivitis and perinatal disease
What kind of transmission do serovars A, B, Ba, and C of the trachoma biovars use?
Hand to eye
Fomites
Flies
Where are LGV biovar infections commonly acquired?
From tropical regions including Northern Australia.
Who gets LGV biovar proctitis?
People who engage in anal sex (MSM populations primarily)
What are the symptoms of LGV biovar infection?
Small genital papule or ulcer
Regional lymph nodes enlarged
Big inflammatory mass (bubo)
Multiple draining abscesses in the groin
Fever and muscle aches
Inflammatory mass heals with scar formation
External genitalia may be deformed by chronic granulomatous ulceration.
Elephantiasis may result
What populations are commonly affected by ocular trachoma?
Indigenous Australians (leading cause of blindness in Australian aboriginals)
What is the leading cause of blindness in the world?
Ocular trachoma
What are the symptoms of ocular trachoma?
Initially produces inflammation of the conjunctiva and cornea
Over time conjunctival surface of the lids becomes scarred and contracted
Eyelashes become turned in resulting in trauma to the cornea and cornea becomes scarred and opaque
What is the world’s most common STD?
Chlamydia trachomatis non-LGV infection
What are the symptoms of non-LGV chlamydia infection?
Urethritis
Epididymitis
Prostatitis
In females:
Cervicitis
Upper genital tract infection (Pelvic inflammatory disease)
Infertility (leading cause)
In newborns it can cause chronic conjunctivitis or chronic pneumonia
What kind of infection does chlamydophila pneumoniae cause?
Mild infection of the upper and lower respiratory tract:
Bronchitis
Mild pneumonia
What kind of disease does chlamydophila psittaci cause?
Parrot fever:
Discharge from eyes or nares
Difficulty breathing
Diarrhoea
Lethargy
Decreased appetite
Weight loss
Depression
What are the symptoms of chlamydophila psittaci?
Flu-like illness:
Non-specific
Fever
Sore throat
Hepatosplenomegaly
Enlarged lymph nodes
Can also produce a typhoid like disease but much less often.
Which pathogen causes walking pneumonia?
Mycoplasma pneumoniae
What is atypical pneumonia?
Pneumonia that in the past was caused by unknown bacteria
What kind of bacteria cause atypical pneumonia?
Chlamydophila pneumoniae
Chlamydophila psittaci
Legionella pneumoniae
Legionella longbeachae
Pneumocystis jeroveci
Why has understanding the role of mycoplasma species been difficult?
Due to them being genital commensals with increased numbers in proportion to sexual activity.
What kind of infections are mycoplasma hominis and ureaplasma associated with?
Pregnancy infections (chorioamnionitis, post partum, post abortal fever)
Neonatal infections (bacteraemia and abscesses)
What diseases are mycoplasma genitalium associated with?
Non-gonococcal urethritis in males
Cervicitis and pelvic inflammatory disease in females
What are anaerobic bacteria defined as?
Bacteria that will not grow on surface of solid agar in air supplemented with 10% O2.
Where are anaerobes located?
Oropharynx
Bowel
Vagina
Skin
What are the degrees of anaerobiasis?
Facultative anaerobes which can grow in O2 or no O2.
Microaerophilic (require low O2)
Obligate anaerobes
What are the levels of tolerance seen in obligate anaerobic bacteria?
Strict (can only tolerate up to 0.5% O2)
Moderate (Tolerate 2 - 8% O2)
Aerotolerant (tolerate atmospheric oxygen for a limited time)
Why is the degree of anaerobiasis important to conisder?
It is relevant for considering:
Where in the body these bacteria are found.
Appropriate specimen collection.
Appropriate culturing conditions in the lab.
What are the anaerobic gram positive cocci?
Anaerococcus
Finegoldia
Parvimonas
Peptococcus
Peptostreptococcus
What are the anaerobic gram positive rods?
Clostridium
Propionibacterium
Actinomyces
Some lactobacillus
What are the anaerobic gram negative cocci?
Veillonella
What are the anaerobic gram negative bacilli?
Bacteroides
Fusobacterium
Mobiluncus
Porphyromonas
Prevotella
What is the common trend with anaerobic bacteria?
They are frequently endogenous:
Normal flora getting access to sterile body site
Often polymicrobial
Sometimes they are exogenous:
Clostridium tetani, perfringens
Bite wound anaerobes
What is a common symptom of endogenous anaerobic bacterial infection?
Pus filled abscesses
Dental infections
What type of pneumonia is associated with anaerobic infections?
Aspiration pneumonia. (often causes lung abscesses)
What kind of lung and pleural infections are caused by anaerobic infections?
Aspiration pneumonia
Lung abscesses
Empyema
Which other tissue can be affected by pus filled abscesses due to anaerobic bacterial infection?
The liver
The peritoneum (peritonitis)
What are the categories of pelvic inflammatory disease and what causes them?
Endogenous: Caused by vaginal bacteria
Exogenous: Caused by STDs such as chlamydia and gonorrhoea
What group of bacteria cause diabetic foot infections?
Anaerobic bacteria
Which bacteria cause necrotizing fasciitis?
Clostridium perfringens (gas gangrene)
Streptococcus pyogenes
Vibrio vulnificus
Aeromonas hydrophila
