1. 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

2. Candidiasis
Candidiasis is a sexually transmitted disease caused by C. Albicans mostly or other pathogenic species of candida .
Hani Masaadeh, MD, Ph.D

3. I. 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).
Dr’s notes: regarding the last point ( I don’t think they are important )
- There are some systemic and local fungal infections
- immunocompromised individuals (aids patients mostly ) will be infected with opportunistic infections from one type of fungi which cause Pneumocystis carinii which is a non pathogenic microorganism for the normal human ( immunocompetent ),, we’ll talk about it in the upcoming slides

4. 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.

5. Characteristics of Fungal Hyphae: Septate versus Coenocytic
Dr’s notes: this is when we do wet mount preparation for suspected candidiasis we can see different forms of fungal hyphae a) septate hyphae b) coenocytic hyphae C) growth of hyphae from spores,, after that multiply and cause pathogenesis by pseudohyphae

6. 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 .

7. 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.
Dr’s notes: regarding point #1 c. albicans prefer acidity and humidity
Point #4 We can use an ordinary media to grow candida albicans but the selective media for it is the sabouraud media (important)**

8. FUNGAL DISEASES (Continued)
Opportunistic mycoses: Caused by organisms that are generally harmless unless individual has weakened defenses:
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 )

9. 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.

10. 063. Intertriginous or flexural candidiasis of the groin may also mimic tinea cruris caused by a dermatophyte. Note erythematous scaling lesions with distinctive border and several small satellite lesions. C. albicans was isolated. (Courtesy Dr D. Hill, Adelaide, S.A.). (dr didn’t read this)
Dr’s notes: this is an area of a high humidity and acidity that’s why it’s a common site for candidiasis, and may cause allergic reaction, pain and redness
063

11. 079. Candida albicans on Sabouraud's dextrose agar showing typical cream coloured, smooth surfaced, waxy colonies.
079

12. 080. Microscopic morphology of C
080. Microscopic morphology of C. albicans showing budding spherical to ovoid blastoconidia.
Dr’s Notes : here you can see the hyphae with c. Albicans (single ones) , the presence of hyphae indicate the pathogenicity of the c. albicans
080

13. 081. Screening test for the identification of C. albicans
081. Screening test for the identification of C. albicans. Production of germ tubes by C. albicans in serum or plasma after 2-3 hours incubation at 37OC. Note characteristic (((germ tubes) the name of the test used for identification of c. Albicans. (important)))**
Dr’s notes: We can observe this reaction by using wet mount preparation from the next suspension which is the colony and serum (plasma) we put one drop on the slide after 3-4 hours and examine it under the microscope by the oil immersion lens.
081

14. 082. Germ tube negative Candida species showing no production of germ tubes in plasma after 3 hours incubation at 37OC. Budding blastoconidia only are seen.
Dr’s notes: this test is observed by wet mount preparation
082

15. 083. Confirmatory test for C. albicans
083. Confirmatory test for C. albicans. Production of large round, thick-walled vesicles (often incorrectly referred to as chlamydoconidia) on Difco chlamydospore agar. Trypan blue in the medium is absorbed strongly by these terminal vesicles. Numerous small blastoconidia and pseudohyphae are also present.
Dr’s notes: this test is also observed by wet mount preparation, but with a different colour (stain) for the detection of budding yeast and hyphae, the light blue colour indicates the presence of hyphea
083

16. 087. CHROMagar Candida plate showing chromogenic colour change for C
087. CHROMagar Candida plate showing chromogenic colour change for C. albicans (green), C. tropicalis (blue), C. parapsilosis (white) and C. glabrata (pink).
087

17. 090 090. Fluconazole Etest and disk test for Candida albicans.
Dr’s notes: this is a susceptibility test for antifungal drugs, note the inhibition zone around the drug, the diameter is wide which indicates that this drug inhibited the growth of c. Albicans which means that it is very sensitive for this drug.
090

18. 092 092. Candida dubleniensis and Candida albicans on CHROMagar.
Dr’s notes : we can see 2 species of candida which gave the same colour, this means that the observation is not enough and we should use other tests for the identification of the candida species.
092

19. 093. Candida dubleniensis and Candida albicans on Bird Seed Agar
093. Candida dubleniensis and Candida albicans on Bird Seed Agar. (Selective media for candida in general)
093

20. So. Candidiasis is a disease caused by candida species (mostly c
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.

21. Trichomoniasis
Here is a link for sketchy microbiology video about trichomoniasis it’s only 5 minutes long, and of great benefit.
all thanks to our colleague Hatem AL- Khashroom for providing it.

22. 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.

23. 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 .
Dr’s notes: T. vaginalis is easily diagnosed by observing a wet mount preparation under the microscope (and it’s enough to diagnose it without the need of other tests ) because of the presence of flagella ( which gives it the high motility )

24. Genus Trichomonas Human Trichomonads:
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.

25. Pentatrichomonas hominis (harmless)
T. tenax (harmless)
T. vaginalis which is a serious sexually transmitted pathogen.

26. 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 vesicles.
Regarding the last 2 point the dr said that a vaginal swab is enough for diagnoses,, and that it infects (females) more than males “so as Wikipedia: It occurs more often in women than men” (which is confusing because the next slide says (both sexes equally susceptible) and the dr read it too )

27. 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

28. T. Vaginalis trophozoite structure
Fg=flagella
Bb=basal body
Nu=nucleus
Ax=axostyle
um=undulating membrane
Cy=cytostomal groove
Cs=costa

29. Dr’s Notes: We can observe T
Dr’s Notes: We can observe T. vaginalis under the microscope because it’s a large MO, note the 5 flagella around the T. vaginalis , it’s very motile and active.

30. Trichomoniasis Epidemiology.
Sexual intercourse, how frequent: world wide.
Male to female ratio, age.
Newoborns and estrogen level.

31. Pathogenesis and immunity
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.

32. Clinical Aspects Females : Persistant vaginitis, 50% asympotmatic.
Discharge 75%.
Vulvar itching and burning 50%.
Dyspareunia 50%.
Dysurea 50%.
Bad (fishy) odor 10%.
Strawberry cervix.

33. 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

34. Diagnosis Clinical picture is very important.
Microscopic morphology (wet mount or angle drop pre)
Male vs female.
Antigen detection.
Look for other venereal diseases.
Dr’s notes: just like we said earlier if the microscopic morphology (wet mount preparation ) is positive we don’t need antigen detection (other tests to confirm )

35. Treatment Metronidazole. Treat sexual partners.
Disulfaran-like effect.
Teratogenicity.
Carcinogenic??

36. 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
%: 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.

37. Focus on pathogen: T. vaginalis
females get a disintegration of vaginal epithelial lining. Natural flora (bacteria ) keep the pH of the vagina at 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.

38. Physical Examination Pelvic examination: Speculum examination:
Inspection of external genitalia.
Speculum examination:
insertion and visualization of vagina and cervix, obtaining swabs and slide specimens.

39. Vaginitis - Trichomoniasis
Profuse, frothy discharge,
yellow-greenish in color
foul odor, vulvar pruritus
Patchy vaginal erythema and
(strawberry cervix)

40. Diagnosis: 1.Vaginal pH 2. Whiff test +
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 antigen- antibody reaction)
7. Polymerase chain reaction
8. Evaluation for other STDs

41. 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

42. 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)

43. 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.
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.
Female pubic louse

44. Pubic lice (cont.) Symptoms: Treatment:
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

45. Scabies (cont.) Symptoms: Treatment:
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

46. For past years Qs go check the last 2 pages of the tafree3’..
BEST OF LUCK ..