Introduction to Infectious Diseases

Bacteria in the environment like in food, water, air, objects, insect bites and animals are considered what type of acquired infections?

Exogenously acquired infections

Bacterial infections caused by agents on or in us such as an alteration of the microbiome or injuries that introduce skin bacteria are considered what type of acquired infections?

Endogenously acquired infections

How do bacterial infections such as chlorea, whooping cough and gonorrhea gain entry into the body?

mucous membrane

insect bites or scratch injuries cause bacteria do invade into cells and tissues. This is an example of what?

bacteria gaining entry through penetration

What are bacterial defense mechanisms? (how bacteria avoid dyeing)

phagocyte avoidance

phagocyte destruction

inhibition of phagocytosis

intracellular parasites

immunologic

bacteria inhabiting body locations with low phagocyte populations

phagocyte avoidance

Movement toward a beneficial chemical gradient or away from a toxic chemical gradient by chemoreceptors

chemotaxis

some bacteria kill phagocytes before or after ingestion

phagocyte destruction

Many bacteria have developed mechanisms that help block the access of phagocytes and immune cells

inhibition of phagocytosis

what are the mechanisms that bacteria have devloped to inhibit phagocytosis?

Polysaccharide capsule

Surface proteins

Fimbriae

Surface slime (biofilm)

Survival Inside of Cells

Some bacteria survive inside of phagocytes, either neutrophils or macrophages. Bacteria that can resist killing and survive or multiply inside of phagocytes or other cells are considered intracellular parasites

intracellular parasites

what are some examples of intracellular parasites

mycobacterium tuberculosis (tuberculosis)

mycobacterium leprae (leprosy)

listeria monocytogenes (listeriosis)

salmonella typhi (typhoid fever)

what are the immunologic defenses that bacteria have?

-Antigenic disguises or variation of antigen

-Immunosuppression

-Induction of ineffective antibody

-Interference with antibodies

a gram stain being positive or negative depends on the composition of _______

the cell wall

gram negative stain shows up what color?

pink

gram positive stain shows up what color

purple

polysaccharide layer that acts as a virulence factor as it prevents phagocytosis

capsulation

what are some obligate aerobes? (bacteria that require oxygen)

mycobacterium tuberculosis

lactobacillus nocardia

what are some obligate anaerobes (dont require oxygen)

Clostridia

Bacteroides

Majority of Marine bacteria

What are the different types of oxygen requirements for growth of bacteria?

obligate aerobs, obligate anaerobes and facultative

What are the different types of growth mediums used to categorize bacteria?

Mannitol Salt Agar

Eosin Methylene Blue Agar

Hektoen Enteric Agar

MacConkey Agar

Chocolate Agar

-An infectious, obligate intracellular parasite comprised of DNA or RNA surrounded by a viral protein coat and/or an envelope derived from a host cell membrane.

-Dependent on host cells for various aspects of growth cycle, replication, and enzymes

virus

the complete infectious virus particle

virion

What are the different types of viruses?

helical virus, polyhedral virus, spherical virus, complex viruses

like the tobacco mosaic virus, which infects a number of different types of plants, have a slinky shaped capsid that twists around and encloses its genetic material

helical viruses

like adenoviruses, which are known to cause a range of illnesses from pink eye to pneumonia, are composed of genetic material surrounded by a many sided capsid, usually with 20 triangular faces

polyhedral viruses

like the infamous coronavirus, are essentially helical viruses enclosed in a membrane known as an envelope, which is spiked with sugary proteins that assist in sticking to and entering host cells

spherical viruses

like bacteriophages, which infect and kill bacteria, resemble. lunar lander and are composed of polyhedral head and a helical body that attach to a cell mambrane so that it can transfer its genetic material

complex viruses

What are the different ways that viruses can be transmitted?

vectors, airborne, indirect or direct contact, waterborne, foodborne

what are examples of vectors?

insects, ticks

What are common pediatric viruses?

erythema infectiosum, measles, mumps, rubella, roseola

what is the medical term for measles

rubeola

cell wall, hyphae, specialized reproduction structures

the structure of fungus

Candidiasis

Cryptococcosis

Histoplasmosis

Pneumocystis

fungal diseases

characteristics of mycobacterium

gram positive, non-motile, non-spore forming, rod shaped

tuberculosis and atypical mycobacterial disease are what type of organism?

mycobacterium

Infections caused by organisms that live off nutrients in the host's body

parasitic diseases

Helminth Infections

Malaria

Pinworms

toxoplasmosis

Trichomoniasis

types of parasitic diseases

an infectious particle made up of protein instead of DNA or RNA

prions

transmissible spongiform encephalopathies (TSEs), such as Creutzfeldt-Jakob disease

prion disease

Congenital Varicella

Herpes Simplex Virus

HPV

Zika Virus

What type of infections can these be?

prenatal transmission infections

-Lyme disease

-Syphilis

spirochetal diseases

Body's overwhelming immune response to severe infection which can result in damaging its own tissues leading to multi-organ failure and death

sepsis