Microbiology• Study of microscopic organisms • Unicellular, multicellular, or acellular • Different fields of study – Virology – study of viruses– Mycology – study of fungi– Parasitology – study of parasites, hosts

and relationships– Bacteriology – study of bacteria– Protozoology – study of protozoa– Nematology – study of nematodes– Phycology – study of algae

What is a Microbe • Smaller than 0.1mm• Includes archaebacteria, bacteria, protozoans, fungi, viruses

Scientific names• Every organism that has been

discovered is given a scientific name

• Founded by Carolus Linnaeus (1735)

• Genus species• G. species• Genus species • Two organisms sharing a common

genus are related

Scientific Names

Examples• Klebsiella pneumoniae• Clostridium difficile• Escherichia coli• Staphylococcus aureus– MRSA

• Streptococcus pyogenes– Flesh eating disease

Why study Microbiology• Microbes are related to all

life– In all environments – Industrial uses

(fermentation, antibiotics, probiotics)

– Related to life processes (food web, nutrient cycling)

– Pathogenic (infectious diseases)

– Most of our problems are caused by microbes

EID’s• Emerging infectious diseases– Weapons of mass destruction– New evolutionary features– Response to man encroaching on the environment

Patterns of Disease• Endemic – disease is

present in low levels of a population at any time

• Outbreak – sudden increase in prevalence of a particular disease

• Epidemic – sudden increase in prevalence on a national scale

• Pandemic – rapid spread of pathogen throughout the world (HIV, bubonic plague, cholera, tuberculosis, HIV/AIDS, influenza)

Patterns of Disease

Biotechnology• Use of living systems and

organisms to develop useful products– Biodegradable plastics,

vegetable oil, biofuels (85% ethanol)

• The use of biological information to make things or improve the human condition– Pharmacogenomics – study

of how the genetic inheritance of an individual affects his/her body’s response to drugs

– Gene therapy

Prokaryotic Cells• Include Bacteria and Archaea• Lacks a nucleus and other

membrane bound organelles• Contain ribosomes• Pili – hair like structures used

to attach to other cells or objects

• Flagellum – tail like extension for motorboating (propeller)

• Cell wall• Nucleoid – chromosomal DNA• Plasmids – small circular pieces

of DNA• Capsule – composed of

polysaccharides, protects cell against phagocytosis

Common Shapes of Prokaryotes • Coccus (Round)– N. meningitidis – meningitis

• Bacillus (Rod)– B. anthracis - anthrax

• Diplococci (Pair)– N. gonorrhoea – gonorrhoea

• Streptococci (chain)– S. pyogenes – scarlet fever

• Spirochete (Spiral)– T. pallidum – syphilis

• Cell walls– Composed of

peptidoglycan • Reproduce

Asexually– Binary fission

• Make energy, use organic chemicals, inorganic chemicals, or photosynthesis

Bacteria

Archaea• Lack peptidoglycan in cell wall• Reproduce via Binary Fission• Live in extreme environments• Methanogens

– Live in environments that lack oxygen

– Produce methan gas– Live in landfills

• Extreme halophiles– Live in environments that love

salt – Dead Sea, Great Salt Lake

• Extreme thermophiles– Live in environments of extreme

heat – Volcanic vents deep in the ocean

Binary Fission• Asexual

Reproduction

Conjugation• Transfer of genetic

material between bacterial cells

• Creates genetic diversity

• Antibiotic resistance

• Unicellular eukaryotes• Animal-like – consumers

• Plant- like– producers

• Motility– Ciliates – Flagellates – Amoeboids– Sporozoan

Protozoa (Eukaryotic Cells)

Animal-like Protists • Ciliates – Move using short, thread like cilia that extend from

plasma membrane – Sweep food into their bodies

• Balantidium coli– Causes Balantidiasis

• Paramecium

Balantidium coli• Trophozoite – Active feeding stage – Binary fission

producing cysts – Invade the wall of large

intestine– Cannot survive outside

human host• Cyst– Dormant, resting stage– transmitted to humans – Survive outside human

host

Animal-like Protists• Flagellates– Use a whipping action (propellor) of tail like flagella

• Giardia lamblia– Causes Giardiasis (beaver fever, backpackers disease)– Reproduce in the small intestine (binary fission)

Giardia lamblia• Trophozoite – Invade wall of large

intestine– Cause severe

diarrhea• Cyst– Dormant, resting

stage– transmitted to

humans – Survive outside

human host

Animal-like Protists• Amoeboids• Pseudopods –

extension of cytoplasm creating foot-like structure for movement and catching food

• Entamoeboa histolytica • Causes Amoebiasis

Entamoeba histolytica • Trophozoite– Invade extraintesinal

sites (liver, brain, lungs)– Cause liver and brain

abscess• Cyst – Ingested by humans

Fecal Oral Route• Pathogens in fecal

matter pass from one host and is introduced to the oral cavity of another

• Excystation /Encystment– Transforming from cyst

to trophozoite and back to cyst

Animal-like Protists• Sporozoans– Cannot move on their own

(nonmotile)– Reproduce both sexually

(gametes) and asexually (mitosis)

– Parasites – Transmitted through vectors

(insects)• Plasmodium vivax– Causes malaria (most common) – Transmitted by female

anopholes (mosquito)

Plasmodium vivax • Mosquito bites

– Infects human with sporozoites

• Sporozoites infect liver cells– Develop into merozoites

• Merozoites infect RBC’s– Continue to infect RBC’s – Some develop into

gametocytes • Mosquito bites infected

human– Gametocytes fertilize,

develop into oocyst• Oocyst ruptures releasing

sporozoites

• Eukaryotes• Cellulose cell walls• Use photosynthesis for

energy (primary producers)

• Produce molecular oxygen and organic compounds

Plant-like Protists (Algae)

Plant-like protists • Dinoflagellates– Marine plankton (flagella)– Red tide

• Algal blooms produce dinotoxins • Toxic to humans

• Diatoms – Phytoplankton– Cell wall is made up silica

• Euglenoids – Contain chloroplasts – Also feed by phagocytosis

• Green Algae – Macroscopic seaweeds

• Eukaryotes• Chitin cell walls• Use organic chemicals for

energy (consumers)• Moulds – consist of masses of mycelia,

which are composed of filaments called hyphae

– Reproduce asexually (spores) • Yeasts – Round shape – Reproduce asexually

(budding)

Fungi

• Acellular – non-living • Consist of DNA or RNA

core• Core is surrounded by

a protein coat• Coat may be enclosed

in a lipid envelope• Viruses are replicated

only when they are in a living host cell

Viruses

Multiplication of Viruses• Adsorption• Penetration• Uncoated• Synthesis• Replication and

Protein Production

• Assembly • Release

Universal precautions set up by CDC• Use gloves,

gowns, masks and goggles

• Minimize risk of needle sticks

• Disinfections procedure

• Preventative treatment after exposure

• Reduce risk• Treat all patients

the same