Microbiology - Fungi & Viruses

Fungi

- eukaryotes

- yeasts and molds

- spore-formers

yeasts

unicellular

molds

multicellular

spore-formers

- some are part of the normal flora

- some are decomposers and pathogens

- divided by budding or fission

Oomycete

mildew, water mold

Ascomycetes

Saccharomyces cerevisiae

Basidiomycetes

mushroom, bracket fungi

Teliomycetes

rust fungi (plant pathogens)

Ustomycetes

smut (plant pathogen)

Deuteromycetes

Aspergillus, Fusarium, Penicillium

polysaccharide, glucan, mannan, chitin, proteins, lipids, mannoproteints

cell wall components

polysaccharide

25% of cell wall

glucan

50 - 60% of cell wall; inner layer; branched polymer

mannan

15-23% of cell wall; outer layer; polymer of mannose

chitin

1-9% of cell wall; inner layer; site of detachment; bud scar

peroplasmic space

space beneath cell wall; secretes proteins and enzymes

plasmalemma

cell membrane (phospholipid bilayer)

Ergosterol

part of phospholipid bilayer; target of amphotericin

Candida albicans superficial infections

oropharyngeal and genital

impaired immune system, catheterization, skin damage

factors causing candidosis (Candida albicans)

virulence factor (Candida albicans)

adherence to host tissue (enzyme activity) and resist

phospholipase and lysophospholipase

damage heat cell (C .albicans)

acid proteinase

adherence, invasion, degradation of IgG and IgA (C .albicans)

aspartate proteinase

vaginal colonization (C .albicans)

hemolysin

access iron from damaged RBC (C .albicans)

Aspergillus fumigatus

opportunistic pathogen - pulmonary aspergillosis (80-90%); affects the brain, kidney, and sinuses; seen in leukemic and organ transplant patients

phospholipase

tissue degradation (A. fumigatus)

protease

tissue degradation and transport from lung to bloodstram, allergens (A. fumigatus)

gliotoxin, fumigatin, fumagilin

toxins of A. fumigatus

Histoplasma capsulatum

causes histoplasmosis

invade and multiply in pulmonary macrophages

virulence of Histoplasma capsulatum

Cryptococcus neoformans

AIDS and meningitis; facultative intracellular pathogen

Dermatophytes

fungi that invade the skin, hair, or nails

Tinea capitis

Microsporum canis and Trichophyton violaceum

Tinea corporis

Trichophyton, Microsporum spp., and Epidermophyton floccosum

Tinea cruris and tinea pedis

Epidermophytom floccosum and Trichophyton rubrum

Tinea mannum

Trichopyton mentagrophytes and Epidermophyton floccosum

Tinea unquium

wide range of fungi

Saccharomyces cerevisiae, Penicillium marnafferi, and non-albicans Candida spp.

merging fungal pathogens

Malassezia furfur

pityriasis (tinea) versicolor

Trichosporon beigelii

white piedra

Fonsecaea pedrosoi

chromoblastomycosis

Acremonium spp.

mycetoma

Blastomyces dermatitidis

blastomycosis

Coccidioides immitis

Coccidioidomycosis (Valley Fever)

Paracoccidioides braziliensis

paracoccidioidomycosis

Pneumocystis jerovecii (carinii)

pneumonia in HIV

amphotericin B and nystatin

amphotericin B drugs

amphotericin B

binds with ergosterol resulting to increase in fungal membrane; permeability forming pores

renal toxicity

side effect of Amphotericin B

Nystatin

same MOA (binds with Ergosterol) as amphotericin; low solubility; topical infection

Azole

most widely used antifungal drug; first generation; mucosal and invasive;

Miconazole

azole with toxic side effects

ketoconazole

azole that has a poor action against aspergillus, and has many side effects

itraconazole

IV formulation azole for systemic infections, against Aspergillus

fluconazole

for systemic infections against Candida albicans

Voriconazole

2nd generation triazole, for systemic infections against pulmonary and cerebral aspergillosis

membrane instability, growth inhibition, build-up of toxic intermediates, cell death

interference with ergosterol biosynthesis with azoles results to

Candida, Cryptococcus, Aspergillus

broad spectrum activity of azoles

Echinocandins

semisynthetic lipopeptides; caspofungin, micafungin, anidulafungin

Caspofungin

fungistatic against Aspergillus; fungicidal against Candida

Flucytosine

synthetic antifungal agent; combination with amphotericin B against Aspergillius

Viruses

filterable agents; identified after the discovery of electron microscope

either DNA or RNA virus; double or single standed linear, circular, or helical

characteristics of viruses

viral capsid

protection of nucleic acid

capsomere

part of viral capsid; shape and resistance

Viral envelope

replication; membrane containing viral proteins

Viral receptors

glycoproteins; recognize host cell receptors

variola

smallpox

vaccinia

cowpox

Adenovirus

URT infection, latent tonsil, and adenoid infection

HSV1

cold sores

HSV2

genital sores

Cytomegalovirus

pneumonia, hepatitis, and encephalitis in immunocompromised patients

varicella zoster

chicken pox

Epstein-Barr virus

Burkitt's lymphoma

hepatitis B

prenatal transmission (children); contact with contaminated blood; sexual transmission

Papilloma virus

warts

Influenza virus

flu

Mumps virus

mumps

Measles virus

measles

Rabies virus

fatal encephalitis

Rotavirus

gastroenteritis

Poliovirus

poliomyelitis

Rhinovirus

common colds

Hepatitis A

infectious hepatitis

Togavirus

rubella (German measles)

Flavivirus

yellow virus; hepatitis C

Aedes and Haemogogus species

vectors of yellow fever (Flavivirus)

Filovirus

Ebola virus

Retrovirus

human T-cell leukemia virus

HIV

AIDS

Hepatitis D

severe hepatitis, co-infection with hepatitis B

multiplication of viruses and destruction of host cell upon release of the viral progeny

viral-host cell interaction

multiplication of the virus and release of the virion without the immediate destruction of the host cell

viral-host cell interaction

survival of the virus in a latent stage without noticeable changes in the infected cell

viral-host cell interaction

survival of the infected cell in a dramatically altered or transformed state

viral-host cell interaction

incorporation of the viral nuclei acid in the host cell genome without noticeable changes to the infected cell

viral-host cell interaction

attachment to the host cell

multiplication of human virus

penetration of the viral particle

multiplication of human virus