Host-Microbe Interactions Flashcards

Vocabulary-style flashcards covering host-microbe interactions, types of symbiosis, the human microbiome, specific bacterial and viral diseases, and epidemiology stages.

Symbiosis

A term derived from Greek meaning 'living together,' referring to interactions between organisms of two different species.

Mutualism

A type of symbiosis where both species benefit from the relationship, such as bees pollinating plants or bacteria in the human gut helping to break down food.

Commensalism

A symbiotic relationship where one species benefits while the other is not affected, such as burrs being dispersed by sheep or fish swimming alongside sharks.

Parasitism

A symbiotic relationship where one organism benefits and the other is harmed, typical of pathogens causing disease.

Amensalism

A relationship where one organism is harmed by the actions of another, while the other does not benefit, such as soil acidification caused by decomposing pine needles.

Opportunistic Pathogens

Microorganisms that are usually harmless members of the microbiota but can become pathogenic if the host's immune system is compromised or if the local environment changes.

Staphylococcus aureus

An opportunistic pathogen found on the skin that can cause severe infections or Toxic Shock Syndrome under certain conditions.

Toxic Shock Syndrome Toxin

A compound produced by S. aureus that causes a massive immune reaction, potentially leading to fever, rash, and fatal loss of blood pressure.

Beta-lactamase

An enzyme produced by S. aureus that makes the bacterium resistant to penicillin-type (Beta-lactam) antibiotics.

MRSA

A resistant strain of Staphylococcus aureus that is specifically resistant to the antibiotic Methicillin.

VRSA

A resistant strain of Staphylococcus aureus that is specifically resistant to the antibiotic Vancomycin.

Streptococcus pyogenes

A facultatively anaerobic, hemolytic Gram-Positive bacterium that causes Pharyngitis (Strep throat), Scarlet Fever, and Rheumatic Fever.

Hyaluronic Acid Capsule

A virulence factor of S. pyogenes used as camouflage to hide from the immune system because it is also found on normal human body cells.

M-protein

A membrane protein of S. pyogenes that protects the bacterial cell from being targeted by immune cells if it is recognized.

Clostridium botulinum

A rod-shaped, gram-positive, spore-forming obligate anaerobe commonly found in soil that produces a powerful muscle-relaxing toxin.

Botulinum toxin

The world's most toxic protein, which binds to neurons and stops them from transmitting messages to muscles, leading to paralysis.

Clostridium difficile

An anaerobic gram-positive spore-forming rod that is a common GI tract member but can cause disease after antibiotic treatments kill other gut flora.

Pseudomembranous colitis

A disease led by C. difficile (c-diff) characterized by inflammation, possible necrosis of the colon walls, and internal bleeding.

Necrosis

The death of tissue, which can occur in the colon walls as a result of toxins and enzymes produced by Clostridium difficile.

Fecal Transplants

A treatment method for recurring C. difficile infections that involves repopulating the patient's GI tract with a healthy community of microbes from a donor.

Mycobacterium tuberculosis

A gram-positive, acid-fast aerobic bacillus that causes tuberculosis, primarily characterized by a persistent productive cough and high survivability outside the body.

Mycolic Acid

The main virulence factor of M. tuberculosis that makes the cell acid-fast, protects it from dehydration, and prevents digestion by immune cell lysosomes.

Bordetella pertussis

A non-motile, aerobic gram-negative coccobacillus that causes pertussis, commonly known as whooping cough.

Pertussis toxin

A toxin produced by B. pertussis that acts as an adhesin to help the bacterium attach to host cells.

Tracheal cytotoxin

A toxin in whooping cough that prevents cilia from moving, causing mucus to stay in place so the bacteria can replicate.

Treponema pallidum

A thin, Gram-negative spirochete and obligate parasite that is the causative agent of the sexually-transmitted infection syphilis.

Chancre

A painless ulcer that forms at the site of infection during the primary stage of syphilis and typically lasts $3$ to $6$ weeks.

Secondary Syphilis

A stage of syphilis occurring $3$ weeks to $6$ months post-infection characterized by a whole-body rash, fever, headaches, and sore throat.

Gummas

Benign tumors that can form in the liver, skin, bone, and cartilage during the tertiary stage of syphilis.

Neurosyphilis

An infection of the nervous system occurring in tertiary syphilis that can lead to severe headaches, convulsions, blindness, and dementia.

Neisseria gonorrhoeae

A gram-negative aerobic diplococcus that causes gonorrhea, a sexually-transmitted disease with different symptoms across genders.

Pelvic Inflammatory Disease

A condition in women caused by N. gonorrhoeae attaching to cells in the cervix, uterus, or fallopian tubes since it cannot attach to vaginal cells.

Enterobacteriaciae

A family of enteric bacteria that includes organisms such as Escherichia coli, Salmonella, and Yersinia.

Coliforms

A sub-group of enteric bacteria that are facultatively anaerobic, gram-negative rods that do not form endospores and can ferment lactose.

Type-3 secretion system (T3SS)

A virulence factor that creates a link between a bacterium and a host phagocyte to inject toxins that induce apoptosis in the immune cell.

Yersinia pestis

The enteric bacterium responsible for the bubonic plague, typically transmitted by fleas on rodents.

Buboes

Very swollen lymph nodes that are a hallmark symptom of the bubonic plague caused by Yersinia pestis.

Jaundice

A symptom of hepatitis characterized by the yellowing of skin and eyes due to the accumulation of bilirubin in the blood.

Hepatitis B Virus

A virus with a partially $dsDNA$ and partially $ssDNA$ genome that replicates with an RNA intermediate and infects liver cells.

Epidemiology

The study of the frequency and distribution of disease and other health-related factors within a population.

Incubation period

The time between the initial infection and the arrival of the first signs or symptoms of a disease.

Nosocomial infections

Diseases that arise specifically when a patient is hospitalized for a condition other than the primary infection.