BM1022 3 Flashcards
Fungi
Non-vascular microbes which reproduce by spores, lack chlorophyll and derive energy from organic matter
Eukaryotic- larger than bacteria
Filamentous hyphae are present
Unicellular fungi are called yeasts
Fungi reproduction
On the reproductive phase highly differentiated spores occur- sexual and asexual spores are produced- spores are often airborne
Fungi 2
Fungi may be pathogens and may form toxins that are cancer producing, spores may cause allergic reactions. May be a source of hallucinogens
Antibiotics are produced by fungi e.g. Penicillin
Superficial mycosea
Example of tinea versicolor
Tropical, patchy, discolouration of skin, interferes with melanin production effects are cosmetic
Caused by a yeast (malassezia fur fur). This yeast is a member of the normal skin flora. Individuals are predisposed by profuse sweating, high temperature, immunosuppression
Infection of the newborn receiving Iv infusions may be lethal
Protozoa
Eukaryotic, small, simple felled animals, may be motile, free living or parasitic
Reproduce asexually and sexually and may possess complex life cycles; some produce resistant survival stages
Trichomonas
Simple life cycles (sexual transmission, present in vagina and male urinary Tracy) the protozoan is a flagellated organism
Giardia
Is a flagellated protozoan which inhibits the intensely one of humans particularly children. Diarrhoea, weight loss and nutritional deficiencies follow. Transmission via food, water and hands contaminated with faces
Plasmodium
Cause malaria
Parasite requires the mosquito for both sexual reproduction and transmission
Parasite reproduces asexually in the human host
In humans the liver and then the red blood cells are invaded, a sexual reproduction of the parasite occurs in these cells
Parasite cells infective to the mosquito are also produced so cycle continues
Massive destruction of circulating red blood cells occurs- affects vital organ function
Toxoplasma gondii (toxoplasmosis)
Intestinal parasite of cats, releases resistant stage(oocytes) in faeces. Survival in soil for several months
Parasite also invades other tissues in cat particularly brain, liver, muscles. No effects usually seen
Intermediate hosts-include humans
ROT Humans- contaminated food (faeces), flies cockroaches
Raw meat
Congenital
Helminths
Are worms, eukaryotic organisms
Are considered in microbiology as the ineffective stages are often microscopic
Parasitic helminths are described as flatworms(tapeworms and flukes) and roundworms or nematodes
Tapeworms
Works consist of a scolex and a row of segments or proottids
Attachment is by means of suckers and hooks
Possess no mouth, digestive tract or vascular system. Nutrients absorbed through outer surface of body
Segments contain male and female reproductive organs
Example of a tapeworm Beef tapeworm (taenia saginata)
Eggs released in faeces (human)? Eggs ingested by beef cattle. Larvae hatch and bore through intestinal wall, migrate to muscle. Become fluid filled sac
Humans infected when eat undercooked meat containing cysticerci. Structure is digested, a scolex is released, anchors to intestinal wall and worm develops. Humans are definitive host
Roundworms
Elongated, cylindrical, unsegmented worms, size varies considerably
Parasitic and free living forms
Generally separate sexed. Female give rise to eggs or living young. Thus, eggs may be infective or larvae
Example of roundworm
Pinworm (enterobius)
Irritation, loss of sleep, loss of appetite, little disease
Female worm lays eggs on perinatal skin
Eggs infective within hours, are ingested, hatch in small intestine
