Transcript T. Vaginalis

Microbiology lecture # 8
This is the last microbiology lecture given by Dr.
Hani Masa’adeh.
We’ll discuss candidiasis, trichomonciaiss and
ectoparasitic infections, 3 easy topics.
Dr’s notes are written in RED
(Make sure to read the notes under each slide(
(**)this sign indicates something important or a past year
question
modified slides done by yara alazzeh
Candidiasis
Candidiasis is a sexually transmitted disease caused
by C. Albicans mostly or other pathogenic species of
candida .
Hani Masaadeh, MD, Ph.D
 I.
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FUNGI (Mycology)
Diverse group of heterotrophs.

Many are ecologically important saprophytes (non pathogenic )
(consume dead and decaying matter)

Others are parasites (pathogenic) .

Most are multicellular, but yeasts are unicellular.

Most are aerobes or facultative anaerobes.

Cell walls are made up of chitin (polysaccharide).

Over 100,000 fungal species identified (most of
them are non pathogenic). Only about 100 are
human or animal pathogens .

Most human fungal infections are nosocomial and/or occur in
immunocompromised individuals (opportunistic infections).
CHARACTERISTICS OF FUNGI
1. Yeasts

Unicellular fungi, nonfilamentous, typically oval or
spherical cells. Reproduce by mitosis:

Fission yeasts: Divide evenly to produce two new cells
(Schizosaccharomyces).

Budding yeasts: Divide unevenly by budding (Saccharomyces).
Budding yeasts can form pseudohypha, a short chain of
undetached cells.
**Candida albicans invade tissues through pseudohyphae.

Yeasts are facultative anaerobes, which allows them to
grow in a variety of environments.

When oxygen is available, they carry out aerobic respiration.

When oxygen is not available, they ferment carbohydrates to produce
ethanol and carbon dioxide.
Characteristics of Fungal Hyphae:
Septate versus Coenocytic
IMPORTANT DIVISIONS OF FUNGI
1. Deuteromycota
 Not
known to produce sexual spores.
 Reproduce

asexually.
Catch-all category for unclassified fungi:
 Pneumocystis
carinii: Causes pneumonia in AIDS
patients. Leading cause of death in AIDS patients.
Candida albicans: Causes yeast infections of vagina in
women, Opportunistic infections of mucous
membranes in AIDS patients And candidiasis on the
mouth cavity .
NUTRITIONAL ADAPTATIONS OF FUNGI
Fungi absorb their food, rather than ingesting it.

Fungi grow better at a pH of 5, which is too acidic for
most bacteria.

Almost all molds are aerobic. Most yeasts are facultative
anaerobes.

Fungi are more resistant to high osmotic pressure than
bacteria.

Fungi can grow on substances with very low moisture but
prefer high moisture .

Fungi require less nitrogen than bacteria to grow.

Fungi can break down complex carbohydrates (wood,
paper), that most bacteria cannot.
FUNGAL DISEASES (Continued)
Opportunistic mycoses: Caused by organisms that are
generally harmless unless individual has weakened
defenses:
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AIDS and cancer patients (leukemia patients ).
Individuals treated with broad spectrum antibiotics. ( long use of
antibiotics will inhibit the growth of normal flora and allow the
candida to grow and multiply )
Very old or very young individuals (newborns).
Examples:

Aspergillosis: Inhalation of Aspergillus spores. (causes systemic
mycoses and one type of pneumonia ) **

Yeast Infections or Candidiasis: Caused mainly by Candida
albicans. Part of normal mouth, esophagus, and vaginal flora
(when exceeds a limited number it will become pathogenic )
Candidiasis
A primary or secondary mycotic infection caused by
members of the genus Candida (the most common is c.
Albicans). The clinical manifestations may be acute,
subacute or chronic to episodic. Involvement may be
localized to the mouth, throat, skin, scalp, vagina, fingers,
nails, bronchi, lungs, or the gastrointestinal tract, or
become systemic (in sever cases) as in septicaemia,
endocarditis and chronic meningitis.
Distribution: World-wide.
Aetiological Agents: Candida albicans (again the most
common) , C. glabrata, C. tropicalis, C. krusei. C.
parapsilosis, C. guilliermondii and C. pseudotropicalis.
All are ubiquitous and occur naturally on humans.
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• So.. Candidiasis is a disease caused by
candida species (mostly c. albicans ) it’ s a
common fungal infection which infects the
genital areas and mouth cavity because of the
normal flora on the mouth contains candida
and when the immunity system goes down the
over growth of this candida becomes
pathogenic, it's treated by antifungal drugs,
sometimes its classified as STD’s when its
present on the genital areas.
Trichomoniasis
Here is a link for sketchy microbiology video about
trichomoniasis it’s only 5 minutes long, and of great
benefit.
https://drive.google.com/file/d/0B3GDHyyfzB2feFJTZ3l
QdTM3NnM/view?pref=2&pli=1
all thanks to our colleague Hatem AL- Khashroom
for providing it.
Introduction
A sexually transmitted disease (STD),
also known as sexually transmitted
infection (STI) or venereal disease (VD),
- is an illness that has a significant
probability of transmission between
humans or animals by means of sexual
contact, including vaginal intercourse, oral
sex, and anal sex.
General properties
Trichomonas vaginalis the only spps.
 Trophozoite (the only pathogenic stage, the

transmission is very easy at this stage)** .
Oval 7-15 microns, large nucleus,
cytostoma.
 5 flagella** (highly motile), undulating
membrane.
 Axostyle.
 Anaerobic growth.
 Survives up to 24 hours outside the human
body .

Genus Trichomonas
• Its includes a group of flagellated
(protozoa) It infect humans and animal
Human Trichomonads:
• 3 species of trichomonads found in
human.
• Two are normally harmless.
• Pentatrichomonas hominis (harmless)
• T. tenax (harmless)
• T. vaginalis which is a serious sexually
transmitted pathogen.
Trichomonas vaginalis:
• It is the etiological agent of trichomoniasis.
• Trichomoniasis is a common sexually transmitted
disease with a worldwide distribution.
• transmittable, sexually and through contact with toilet
seats and towel ( because it can survive up to 24 h outside the human
body, so although it's a sexually transmitted disease it's not only transmitted
by sex. ) .
• T. vaginalis despite it name, infect both men and
women.
• In females the organism inhabits the vagina and
urethra.
• In males it is found in the urethra, prostate or, seminal
• The life cycle consist only of a trophozoite stage
which is transmitted by direct contact during
sexual intercourse
• “both sexes equally susceptible”
Again Dr said it affects females more than males
and Wikipedia approves : (It occurs more often
in women than men) so it’s up to you :P
T. Vaginalis trophozoite structure
•
•
•
•
•
Fg=flagella
Bb=basal body
Nu=nucleus
Ax=axostyle
um=undulating
membrane
• Cy=cytostomal
groove
• Cs=costa
Trichomoniasis

Epidemiology.

Sexual intercourse, how frequent: world
wide.

Male to female ratio, age.

Newoborns and estrogen level.
Pathogenesis and immunity



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Direct contact causes all the problems.
Not invasive, no toxins.
Glycoprotein 200k could be responsible.
Vaginal environment plays the major role.
Immune response is of little significance.
Clinical Aspects
Females :
 Persistant vaginitis, 50% asympotmatic.
 Discharge 75%.
 Vulvar itching and burning 50%.
 Dyspareunia 50%.
 Dysurea 50%.
 Bad (fishy) odor 10%.
 Strawberry cervix.
Clinical Aspects

Males:
Urethritis and Prostatitis.
 Asymptomatic.
 Dysurea.
 Non purulent discharge.
 Non gonococcal urethritis.
The clinical aspects on the male is less than
female due to anatomical structure

Diagnosis
Clinical picture is very important.
 Microscopic morphology (wet mount or
angle drop pre)
 Male vs female.
 Antigen detection.
 Look for other venereal diseases.

Treatment

Metronidazole.
Treat sexual partners.
 Disulfaran-like effect.
 Teratogenicity.
 Carcinogenic??

Sign and symptoms:
•
•
•
T. vaginalis causes different manifestation in men and women.
Women are more likely to exhibit symptoms which tend to persist longer
Incubation period is 4-28 days.
•
In female ranges from asymptomatic, to mild or moderate irritation, to extreme
vaginitis
•
10 - 50%: asymptomatic
•
The commonest symptoms: vaginal discharge, vulval itching, dysuria, or offensive
odor , rare abdominal discomfort.
•
Vaginal discharge: up to 70% - varying in consistency from thin and scanty to profuse
and thick; the classical discharge of frothy yellow occurs in 10-30% of women
•
Extreme cases associated with vulvitis and vaginitis.
•
2%: strawberry cervix appearance to the naked eye.
Focus on pathogen: T. vaginalis
• females get a disintegration of vaginal epithelial
lining. Natural flora (bacteria ) keep the pH of the
vagina at 4-4.5 and ordinarily this discourages
infections.
• T. vaginalis can survive at a low pH.
• Once established it causes a shift toward
alkalinity (pH 5-6) which further encourages
its growth. There is a tendency to explain
stillbirths, spontaneous abortions, morbidity to
women who have vaginitis.
Physical Examination
• Pelvic examination:
– Inspection of external genitalia.
• Speculum examination:
– insertion and visualization of vagina and cervix,
obtaining swabs and slide specimens.
Vaginitis - Trichomoniasis
– Profuse, frothy discharge,
yellow-greenish in color
foul odor, vulvar pruritus
– Patchy vaginal erythema and
(strawberry cervix)
Diagnosis:
1-Specimens:
– vaginal discharge (usually)
– urine sediment
– prostatic secretion (males)
1.Vaginal pH
2. Whiff test +
3.Wet mount (if it is positive+ it’s enough ) **
4. Pap smear
5. Culture
6. Direct immunoflouresence assay (to study antigenantibody reaction)
7. Polymerase chain reaction
8. Evaluation for other STDs
Potassium hydroxide amine test (Whiff test**) :
Upon application of 10% potassium hydroxide (KOH) to a
vaginal swab sample, a fishy odor is released, which can
suggest trichomoniasis or bacterial vaginitis **
Whiff test: 10 % KOH
Ectoparasitic infections
• Ectoparasites: parasitic organisms that live
on the outer skin surfaces (unllike the previous 2
that lived on the inside)
• 2 common STIs caused by ectoparasites:
1) pubic lice )‫(قمل العانة‬
2) Scabies )‫(الجرب‬
Pubic lice (a.k.a. crabs)
• Caused by: biting louse called
Phthirius pubis**
• Prevalence: more prevalent
among young (15-25 yr.old)**
single people, often associated
w/presence of other STIs.
Female pubic louse
• Transmission: during sexual contact when two
people bring their pubic areas together
– Lice can live away from the body for as long as 1 day**-can drop off onto underclothes, beds heets, etc, and eggs
deposited by female louse can survive for several days
• Therefore, it is possible to get pubic lice by sleeping in someone’s
bed or wearing someone’s clothes.
Pubic lice (cont.)
• Symptoms:
– Itching (that’s not relieved by
scratching)
– Can also leave bluish-grayish
marks on the thighs and pubic
area from bites
– Self-diagnosis is possible by locating
a louse on a pubic hair
• Treatment:
– medicinal lotion (1% permethrin or pyrethrin)** applied to all
affected areas + all areas w/body hair (genitals, armpits,
scalp, even eyebrows);
– wash all clothes and bedding that were exposed
• Symptoms:
Scabies (cont.)
– Small vesicles or pimple-like
bumps, red rash
– Intense itching
– Favorite sites of infestation:
webs and sides of fingers, wrists,
abdomen, genitals, buttocks,
and female breasts
• Treatment:
– medicinal lotion (prescription & nonprescription available)
applied at bedtime, then washed off after 8 hrs
– wash all clothes and bedding that were exposed
• For past years Qs go check the last 2 pages
of the tafree3’..
BEST OF LUCK ..