THE HUMAN MICROBIOME
This term means “a human plus all of its resident microbiota.”
What is a holobiont?
Pathogenic microbes penetrate host defenses, enter tissues, and multiply—this is the definition of this process.
What is infection?
This is the characteristic route a microbe takes to initiate infection (skin, mucous membranes, etc.).
What is a portal of entry?
This is the degree of pathogenicity; it is measured by how well a microbe can establish itself and cause damage.
What is virulence?
This is the time from initial contact with the infectious agent until the first symptoms appear.
What is the incubation period?
The Human Microbiome Project showed that healthy people carry these in low numbers—even potentially dangerous ones.
What are (potentially dangerous) pathogens?
This type of infection is caused by the host’s own normal biota (example: S. pneumoniae causing pneumonia in an AIDS patient).
What is an endogenous infection?
These are the three skin sites where microbes most easily enter.
What are nicks, abrasions, and punctures?
This toxin is actively secreted by living bacteria into tissues (many types exist)
What is an exotoxin?
Earliest notable (but often vague) symptoms appear during this period.
What is the prodromal period?
Breast milk contains Approximately this number of species of bacteria plus sugars that feed healthy gut bacteria in infants.
What is Approx. 600
This is the minimum number of microbes needed to start an infection; smaller numbers = higher virulence.
What is infectious dose (ID)?
This process lets microbes gain a stable foothold on host tissues via specific molecule binding.
What is Adhesion
These secreted proteins (mucinase, keratinase, hyaluronidase) break down tissues and help microbes spread.
What are exoenzymes?
The infectious agent multiplies at its highest level and shows greatest virulence in this phase.
What is the acute phase?
“Good” microbes use this general effect to prevent intruders from taking over.
What is microbial antagonism?
Many scientists now believe most infections are this type, with more than one microbe contributing (example: flu → bacterial pneumonia).
What is polymicrobial?
These virulence factors help pathogens avoid or survive inside phagocytes (kill the phagocyte, block engulfment, or live inside them).
What are antiphagocytic factors?
This toxin is lipopolysaccharide (LPS) that sheds from the outer membrane of Gram-negative bacteria.
What is an endotoxin?
This is transmission from parent to offspring via placenta, milk, ovum, or sperm.
What is vertical transmission?
Sites now thought to harbor normal microbiota (or their DNA) include the lungs, placenta, brain, and bloodstream.
What are additional sites now thought to harbor normal microbiota (or their DNA)?
True pathogens cause disease in healthy people; this other type only causes disease when host defenses are weak or the microbe is in the wrong body site.
What is an opportunistic pathogen?
Intact skin is a tough barrier, but some microbes make their own entry using digestive enzymes—this describes which portal.
What is the gastrointestinal tract (or skin, respiratory, urogenital portals)?
Long-term or permanent damage after infection (example: deafness after meningitis or arthritis after Lyme disease).
What are sequelae?
A live animal (usually an arthropod) that carries the pathogen; a biological one actually multiplies the microbe inside itself.
(Other term used instead of Resevoirs)
What is a (biological) vector?