Microbiology

Cell

Smallest unit of life

Microbe

a living creature that is too small to see with a microscope

Four pathogens:

Bacteria-single celled, most respond to antibodies

Viruses-hijack your own cells to replicate, antibodies not as effective, non cellular, genetic material may be DNA or RNA, cannot replicate without host

Fungi-opportunists that strike when immunity is low

Parasites-often traced through travel, water, or food history

Nomenclature and species

species are defined by genetic relatedness

Prokaryotic

No nucleus, no organelles, includes bacteria and archaea

Eukaryotic

Has a nucleus and organelles

Pathogen

producer of disease: pathogenicity is a microbes ability to cause disease, includes all pathogens, some pathogens are harmless unless an opportunity arises

Parasite

Colonizes and harms host. Colonization is ability for microbe for stay attached and replicate. Can be referred to as protozoa and worms

Koch’s postulates

how to link a pathogen to a disease

Virulent

A disease that’s extremely dangerous, highly infectious, and spreads very fast

Stages of infectious disease

1.Incubation-no signs or symptoms

2.Prodromal-mild signs or symptoms

3.Illness period-Most severe signs and symptoms

4.Decline period-Signs and symptoms

5.Convalscene-Recovering health and strength after illness

Stages of infectious disease continued

Chronic-Gradual, slow to heal, 3+ months (Ex:tuberculosis)

Acute-Develops rapidly (Ex:strep throat)

Latent-Present without symptoms (cold sores due to herpes)

Host range

Narrow-Salmonella typhi infects humans only

Broad-Salmonella typhimurium infects other animals in addition to humans

Direct Transmission

pathogen passes when physical touch occurs between an infected individual and a healthy person (ex: kissing)

Vector transmission

a living organism that carries and transfers an infectious pathogen from an infected host to a new host

Mechanical vector transmission

when a living organism like a human or animal carries a pathogen outside of it’s body and transfers it to a new host without being infected itself

Transovarial transmission

the passing of a pathogen from an adult female vector, like a tick or a mosquito, to its offspring through the ovaries and eggs

Transplacental transmission

transfer of a pathogen, cell, or antibody from a pregnant woman to her fetus via the mother’s bloodstream

Vehicle transmission

pathogens move through contaminated inanimate or fomite object like doorknobs, computers, etc

Indirect transmission

the transfer of an infectious agent from a reservoir to a host using an intermediate object (ex: touching a doorknob while being sick)

zoonotic disease

infections normally in animals but than can be transmitted to humans

Endemic disease

always around us

Epidemic disease

more regional

Pandemic

More global, spread around the world

Contact

Bacteria on surfaces, use gloves, and diseases like C. Dif, ESBL

Droplets

Sneezing, surgical mask, and diseases like influenza, meningitis

Airborne

stays in the air like smoke, N95 respirator, negative pressure room: air enters patients room and air forced suction out from the room and filter passes, positive pressure room: air enters patients room and the air inside is pushed out, which is air that is contaminated from the virus from patient

Asymptomatic carrier

contains the potential disease, but doesn’t show signs or symptoms