Lab 7 Genital Tract Infections Flashcards
Genital tract specimens are cultured to determine which diseases in females?
In females:
1. Cervicitis
2. (vulvo)-vaginitis
3. urethritis
4. salpingitis (pelvic inflammatory disease - PID)
5. Endometriosis
6. Genital ulcers
7. Bacterial vaginosis
Which diseases are genital tract specimens cultured for males?
In males:
1. Epididymitis
2. Urethritis
3. Prostatitis
4. Genital ulcers
How can genital infections affect newborns?
There are infections associated with childbirth and neonates from genital infections.
What is a common cause of cervicitis and urethritis that specimens are commonly sent to the lab for?
Chlamydia trachomatis
- collected to determine the presence of.
What is Neisseria gonorrhoea the causative agent of and is it a common specimen to send to the lab?
Neisseria gonorrhoeae, the agent of gonorrhea (‘GC’).
What affects the normal flora of the female genital tract?
Normal flora varies with age, hormonal levels, and pH.
What does the prepubescent (before menstruation) flora of the female genital tract?
Corynebacterium spp. (diphtheroid)
Coagulase negative Staphylococcus
Various anaerobes (skin like)
What is the reproductive age flora like and the organisms in female genital tract?
Reproductive age –> acid pH in genital tract of females.
Organisms include:
1. Lactobacilli
2. Corynebacterium spp.
3. Enterobacterales
4. Streptococci (including group B, should be reported in pregnancy)
5. Coag Neg Staph
6. S. aureus (unless its toxic shock syndrome)
7. Enterococcus spp.
8. Anaerobes
9. Yeast
What is the post-menopausal age normal flora like in females?
Fewer Lactobicilli
More Enterobacterales
may lack the yeast and mycoplasmas
What is the normal flora of the urethra for males?
The normal flora of the urethra includes relatively few skin organisms:
1. Coagulase-negative
staphylococci,
2. Corynebacterium spp,
3. Viridans streptococci.
What normal flora is on the external areas of the genital tract, the vulva and prepuce of the penis?
Both of the external areas of the genital tract- the vulva and the prepuce of the penis- may have:
1. Mycobacterium smegmatis,
2. other Gram positive bacteria and
3. some yeasts.
What condition/organism are routine genital specimens typically cultured for?
Routine genital specimens for culture are done basically just for GC, and in the majority of cases this is not even done by culture.
Candida albicans is a possible pathogen but in the last years diagnosis by culture has been replaced with observing yeast on a Gram-stained slide.
Trichomonas can be diagnosed with a wet mount, but its sensitivity is not too high and it gets higher using kits that detect surface antigens on the parasite and are ready in a few minutes.
GC = gonorrhea
What other methods (besides culturing) is used to diagnose GC (gonorrhea)?
Other methods:
- -> molecular-based/amplification
have replaced cultures for GC mostly, but some cultures are still received in labs. Selective media needs to be used for these.
Pre-analytically, what organisms are vaginal specimens for?
Vaginal specimens for:
Candida spp.
Trichomonas vaginalis
Bacterial vaginosis
Pre-analytically, what organisms are cervical specimens for?
Cervical specimens for:
Neisseria gonorrhoeae
Chlamydia trachomatis
Ureaplasma urealyticum
Pre-analytically, what organisms are urethral specimens (discharge - rarely asymptomatic) for?
Urethral specimens- discharge (rarely asymptomatic):
Staphylococcus aureus (more for wound-like specimens)
Beta-hemolytic streptococcus- Group A (uncommon)
Neisseria gonorrhoeae (also antigen detection)
Urethral specimens are also tested for the same pathogens as cervical specimens, with tests for Chlamydia trachomatis, Ureaplasma urealyticum, and Mycoplasma hominis found from most nongonococcal infections. (Exception- HPV)
External genitalia specimens- male and female
These infections are characterized by the presence of lesions or chancres, and include tests for:
- Treponema pallidum (syphilis-chancre)- dark-field or fluorescent antibody preparations, serology
- Haemophilus ducreyi (chancroid)-
- HSV types 1 & 2 (herpes genitalis)- culture;
- HPV (venereal warts) .
Candida is a pathogen to look for on external genitalia too.
What are reason that cause unacceptable genital tract specimens?
Unacceptable Specimens:
1. Specimen leaking
2. Improper container- specifically Neisseria gonorrhoeae loses viability easily and therefore should be sent in charcoal transport medium or specific test containers.
3. Clerical error (labeling, wrong info)
4. Specimen > 24 h old (depending on request & container)
5. Improper storage eg. refrigerated, frozen or left in transit at < 35ºC
6. Request for anaerobes
7. Lubricant used to collect
8. Vaginal specimen for GC or Chlamydia (should be cervix).
9. Do not accept vaginal swabs from women in childbearing years for “routine genital culture”. The disease or agent sought should be ordered specifically.
Why is a routine culture for genital tract specimens so limited (i.e. not a wide practice)? What is most often needed from the doctor?
“Because the agents of disease have diverse
culture and detection requirements
and selective media are often needed, a
“routine” genital culture, with the intent
to “detect what is there,” rarely has an indication. Occasionally such specimens are appropriate for prepubescent or postmenopausal women. Otherwise, laboratories
should provide a special requisition, such as in…, to be used to request the appropriate tests according to
the clinical condition and/or pathogen of interest.”
What media is used for Cervical / Urethral- Culture for GC?
Modified Thayer Martin (MTM), Chocolate Agar (CA)
incubated in CO2.
CA (non-selective is needed because there is a small number of GC (2%) that might be inhibited by MTM.
BA is also used in RRC lab for teaching purposes.
What media is used for Vaginal/ labial swab- for yeast?
(BA), SAB. Look for: Candida (on SAB & BA)= for vaginal specimens test on Gram smear and for external genitalia do culture.
Why might lack of isolation of a pathogen in the lab not indicate the pathogen is not the cause of the disease?
Many agents of disease are difficult to culture, and the lack of isolation may not indicate that the pathogen is not the cause of disease.
Why will a routine genital culture not detect presence of GBS? What is a better method?
Unless selective media and incubation are used, a routine genital culture will not detect carriage of GBS in all cases.
Methods that employ DNA detection (DNA probe or ‘PCR’) for the detection of GBS are more rapid than culture techniques.
What can cause false negative cultures?
False-negative cultures can result from contamination of the specimen with:
- Genital microbiota,
especially E. faecalis, or - From the inability to recognize non-hemolytic colonies (for GBS).
What is BV best diagnosed by?
What does BV stand for? Ask Mariella, guess Bacterial vaginosis
Because of the difficulty in evaluating the significance of G. vaginalis in culture, unless it is clearly predominant and numerous, BV is best diagnosed by Gram stain (Nugent score) or/and in the Physician’s office (sniff test)
Why is more than one confirmatory method is required for ID of N. gonorrhoeae in the case of child abuse?
More than one confirmatory method for identification of N. gonorrhoeae is essential for potential cases of child abuse, since nearly every method has some errors.
For what culture/condition is unscented white wax candles used for and why?
If using candle jars to generate a CO2 atmosphere, use only unscented white wax candles. Colored candles yield toxic substances for GC.
GC = gonorrhea
Describe the expected colony morphology on CA plates for Neisseria Gonorrhoeae (GC)? Gram stain?
Small, translucent, gray and mucoid colonies.
Gram stain: g-dc
