Unit 3 Microbiology

Fungi are…

Eukaryotes with membrane-bound organelles

Single celled Fungi

yeast

Multicellular fungi

molds and mushrooms

4 types of fungal forms

Yeast- round/oval shape, asexual reproduction

Hyphae- long, threadlike cells found in filamentous fungi

Dimorphic- can take either form

Pleomorphic

Thermally dimorphic meaning

Mold when growing saprophytically 25-30 C

Yeast in animal tissues 37 C

Mycelium

woven, interwinding mass of hyphae; make up body or colony of mold

Septa

cross walls that divide hyphae into segments

Spores

fungal reproductive bodies

Fungal cell envelope

Cell walls containing chitin

Fungal asexual reproduction

Growth of existing haploid

Fragmentation

Sport formation

Fungal sexual reproduction

Brief diploid stage

Spore formation

Primary fungal infections

sicken healthy

Opportunistic fungal infections

sicke those who are weakened

Superficial fungi…

colonize hair, skin, nails; infect only surface layers

Candida albicans transmission mechanism

Normal gut flora, nosocomial

Candida albicans diagnostics

Pleomorphic

Outside: yeast

Inside: mold

Candida albicans clinical manifestations

Candidiasis

-Thrush

-Vaginal yeast infection

-Diaper rash

-Bloodstream infection in hospitals

Trichophyton spp. general transmission mechanism

Contact with spores (direct or indirect)

Trichophyton spp. causes ________

dermatophytosis

3 types of Trichophyton spp.

Tinea pedis

Tinea corporis

Tinea cruris

Tinea pedis

Type of Trichophyton spp.

Athlete’s foot

Locker room floors, shower

Tinea corporis

Type of Trichophyton spp.

Ringworm

Sharing of clothing/sheets, barefoot in locker rooms, beach

Tinea cruris

Type of Trichophyton spp.

Jock itch

Often spreads from athlete’s foot

Subcutaneous fungi

colonize deeper layers of skin, usually from implantation into skin through trauma

Sporothrix schenckii transmission mechanism

Subcutaneous

Spores entering skin

Sporothrix schenckii diagnostics

Thermally dimorphic

Sporothrix schenckii clinical manifestations

Sporotrichosis (Rose gardener’s disease)

Fonsecaea pedrosoi transmission mechanism

Subcutaneous

Implantation of spores (thorns or splinters)

Fonsecaea pedrosoi diagnostics

Mold

Fonsecaea pedrosoi clinical manifestations

Chromoblastomycosis: slow growing, warty, cauliflower-like nodules

Systemic fungi

Infection by inhaling spores

Fungal growth in internal organs

Can be primary or opportunistic

Histoplasma capsulatum transmission mechanism

Systemic

Breathe in spores (Bird and bat poop)

Histoplasma capsulatum diagnostics

Thermally dimorphic

Histoplasma capsulatum clinical manifestations

Histoplasmosis: cough, flu-like symptoms, skin/mouth lesions if disseminated

Coccidioides immitis transmission mechanism

Systemic

Soil: disrupted by rain, construction, dust storms

Coccidioides immitis diagnostics

Thermally dimorphic

Coccidioides immitis clinical manifestations

Coccidioidomycosis or Valley Fever: subcutaneous lesions bronchitis or pneumonia, fatigue

Cryptococcus neoformans transmission mechanism

Systemic

Soil containing pigeon/bird droppings

Cryptococcus neoformans diagnostics

Encapsulated yeast

Cryptococcus neoformans clinical manifestations

Cryptococcosis: wound or cutaneous, pulmonary, meningitis

2 subgroups of kingdom protista

Algae and Protozoa

Protist defenition

unicellular or colonial organism lacking true tissues

Protists are…

heterotrophic and require their food in complex organic form

Parasitic protists feed on:

Host fluids (plasma and digestive juices) and tissues

2 stages of protist life cycle

Trophozoite- motile and feeding stage

Cyst- Dormant, resting stage

Protist life cycle dicatates _____

mode of transmission

Protists reproduce…

Asexually and sexually

Pseudopods

Style of locomotion also a feeding structure

Flagella

Style of locomotion that can vary from 1 to several

Cilia

Style of locomotion that covers entire cell surface

Amoeba

Pseudopods

Asexual reproduction

Uninucleate

Most form cysts

Most free-living

Ciliates

Cilia

Sexual and asexual reproduction

Macro and micronuclei

Most from cysts

Most free-living

Flagellates

Flagella or flagella and amoeboid motion

Sexual reproduction

Uninucleate

Form cysts

Most free-living

Protozoal without motility

Complex life cycles

Sexual and asexual reproduction

Macro and micronuclei

Produce infective spores

All within group Sporozoa

All are parasitic

Entamoeba histolytica transmission mechanism

Fecal-oral (contaminated produce of water)

Entamoeba histolytica diagnostics

Produces cysts

Entamoeba histolytica clinical manifestations

Amoebic dysentery: violent bloody diarrhea → dehydration and fever

Entamoeba histolytica control of infection

Increased sanitation of toilets and handwashing

Water filtration

Naegleria fowleri transmission mechanism

Found in warm waters

Enters nose → nasal tissue → brain

Bacteria-eating free-living amoeba

Naegleria fowleri diagnostics

Forms cysts

Naegleria fowleri clinical manifestations

Naegleriasis: primary amoebic meningoencephalitis

Naegleria fowleri control of infection

Chlorination helps

-Keep water out of nose

-Boil your Neti-Pot water

Acanthamoeba spp. transmission mechanism

Soft contact lenses contacting either life cycle stage

-Contaminated lens solution

-Swimming and bathing

-Soil

Acanthamoeba spp. diagnostics

Produces cysts

Acanthamoeba spp. clinical manifestations

Acanthamoeba Keratitis: Cornea infection → blindness

Acanthamoeba spp. control of infection

Wear contacts <12 hours per day

-Disinfect lenses

-Replace contacts regularly

-Remove contact before any water activity

-Wash hands before handling contacts

Types of Amoeboid Protozoa

Entamoeba histolytica

Naegleria fowleri

Acanthamoeba spp.

Types of Ciliated Protozoa

Balantidium coli

Balantidium coli transmission mechanism

Zoonotic: fecal-oral from pig (contaminated water)

Balantidium coli diagnostics

Produces cysts

Balantidium coli clinical manifestations

Balantidiasis: large intestinal infection - chronic diarrhea, dysentery

Balantidium coli control of infection

Good hygiene, only eating cooked foods, and wash fruits and vegetables

Types of Flagellated Protozoa

Trypanosoma cruzi

Giardia lamblia

Trichomonas vaginalis

Reservoir host

A primary host harboring a pathogen

Asymptomatic

Source of infection

Biologist vector

Any living agent that carries and transmits an infectious pathogen to another living organism

Trypanosomes

Long, crescent-shaped cells; single flagellum

In blood during infection

Transmitted by blood-sucking vectors

Trypanosoma cruzi transmission mechanism

Vector: kissing bugs

Reservoirs: armadillos, opossums, raccoons

Trypanosoma cruzi diagnostics

No cyst stage

Trypanosoma cruzi clinical manifestations

Chagas disease

-Early: fever, swollen lymph nodes

-Late: enlarged esophagus and colon or heart failure

Trypanosoma cruzi control of infection

-Avoid sleeping in a mud, thatch, or adobe house

-Use bed net

-Use insecticides

-Use inspect repellent

Giardia lamblia transmission mechanism

Fecal-oral, contaminated water and food

Reservoirs: dogs, cats, beavers

Giardia lamblia diagnostics

Cyst producer

Giardia lamblia clinical manifestations

Giardiasis: small intestine dysentery

-world: 250 million/yr.

-symptoms: none → abdominal discomfort, chronic diarrhea

-Decreased fat and carbohydrate digestion

Interfere with vitamin and nutrient absorption (long-standing infection)

Giardia lamblia control of infection

Good hygiene

Avoid drinking unfiltered stream water

Wash fruits and vegetables

Do not let your dog lick your face