M7 Genital Tract Infections Flashcards
What is normal flora for the urethra?
Coag neg Staph & Corynebacterium, some anaerobes (skin-like)
What normal flora organisms may the Vulva & penis (prepuce) have?
May have Mycobacterium smegmatis & other Gram+
What does the female genital normal flora vary with?
Female varies with pH and estrogen (age).
What organisms are in the female prepubescent and menopausal normal flora?
Prepubescent & menopausal:
Staph & Coryne (skin-like)
What organisms are in the female reproductive age normal flora? How do they provide protection?
Reproductive age:
Enterobacterales
Staph- Strep
Anaerobes (varied, mainly
Lactobacillus)–> Predominant
Keeps pH @ 4 + H2O2+ –>protection
What is the difference between exogenous and endogenous genital infections?
Exogenous: from interaction with others (STI’s)
Endogenous (from normal flora)
What parts of the female are considered lower genital tract and what parts are upper genital?
Female
1. Lower genital tract (vulva, vagina, cervix)
2. Upper genital tract (reproductive + abd cavity)
Infections can start as a lower and progress to upper (same in males: from urethral infection to epididymis)
How many sexually transmitted genital infections can you list?
Sexually transmitted:
1. Urethritis-cervicitis
a. Chlamydia trachomatis
b. Neisseria gonorrhoeae
2. Trichomonas vaginalis
3. HIV
4. Treponema pallidum (Syphilis)
5. Ureaplasma urealyticum
6. Mycoplasma hominis
7. Herpes simplex virus
How many genital infections (non-sexually transmitted) can you list?
- Vaginitis: Candida,
Trichomonas - Bacterial vaginosis
- E. coli or other GNB in prepubescent
- Strep Gr B and Listeria in pregnancy
- S. aureus in Toxic shock syndrome
What type of transport medium is used on a vaginal swab for GC?
Amies or Stuart’s Transport Media w/charcoal
- salt and mineral concentrations conducive to recovery of pathogens including N.gonorrhoeae
- charcoal is added to further increase recovery of N.gonorrhoeae
What are the transportation limitations for GC?
Storage of specimens: for GC, ideally less than 12 hours of transport at R.T. (No fridge!)
or a special commercial system or planting straight to plates.
What organisms are included in a prenatal screen?
Streptococcus agalactiae:
Screening with LIM broth (enrichment), then subbed to BA
Now Chromogenic agar is starting to be used.
Listeria monocytogenes, cultured under request (BA)
How can prenatal infections occur with S. agalactiae (Group B)?
- Rupture of vaginal membranes during birth lead to infection in neonates
- Late trimester fetus or neonates primarily affected (not the pregnant woman)
How can prenatal
infections occur with L. monocytogenes?
- Dissemination of organism through the bloodstream
- Early trimester fetus primarily affected
Looked for in stillbirth samples (NP swab of baby and placenta swab)
How does the typical hemolysis of S. agalactiae compare with Group A Strep?
S. agalactiae – dull narrow zone hemolysis
Whereas Group A strep typically has a wider zone of hemolysis.
What colony morphology is expected and tests are performed for suspected S. agalactiae?
- Colony description: sm grey/wt beta haem (narrow)
- the sole member of Lancefield group B, forms small 3 to 4 mm, grey-white colonies that have a narrow zone of beta hemolysis on blood agar.
- Gram : G+ c prs, chains
- Catalase: θ
- Bac – Res; CAMP +
What is the final confirmatory test for suspected S. agalactiae?
Latex agglutination with specific antisera: Lancefield identified the group B antigen, a cell wall-associated carbohydrate that distinguishes GBS from other streptococcal species.
What does the CAMP test look for in S. agalactiae?
A positive GBS Camp test shows a positive zone of enhanced hemolytic activity (shown by arrow head), whereas a non-positive test shows a non-enhanced zone of hemolytic activity.
S. Agalactiae produces a CAMP factor that enhances hemolysis when it acts synergistically with a beta-lysin producing strain of S. Aureus.
What is the colonial morphology of Listeria spp.? How can it be confused with Group B strep?
Colonial Morphology:
β-sm trans
has a narrow-zone β-hemolysis on sheep blood agar, resembling Group B strep
What does Listeria spp. look like on a gram stain?
Listeria spp. gram stain:
Gram positive bacilli which can resemble cocci or coccobacilli.
Liquid media shows bacilli forms more apparent, T or F?
True: CSF
bacilli forms more apparent
in liquid media
What tests are performed to confirm suspected Listeria spp. ID?
Catalase positive
Enhanced motility at cooler temperatures (20o-25oC) (end-over-end in wet mount, umbrella pattern in soft agar)
API Listeria or other automated methods (Vitek, Maldi-Tof)
What four organisms are the main causative agents of STI’s?
Neisseria gonorrhoeae
Treponema pallidum
Trichomonas vaginalis
Chlamydia trachomatis
What pathogenicity factors does N. gonorrhoeae have?
- Attachment to epithelial cells via pili major virulence factor
- Inflammatory response leads to engulfment of gram negative diplococci by neutrophils
- Destruction of bacteria by
host defenses hindered by
pili
What pathogenic symptom does N. gonorrhoeae cause?
Symptoms include purulent
discharge.
What are the most common body part in male & female specimens are taken for Neisseria gonorrhoeae (GC)?
Common specimens
Urethral (male)
Cervix (female)