Chapter 11 Flashcards
The Human Microbiome Project (HMP)
Characterizes microbes living ON or IN us
(T/F) Not all healthy people seem to harbor potentially dangerous pathogen in low numbers
False. All healthy people harbor potentially dangerous pathogen even in low numbers
Infection
microbes get past host defenses, enter tissues, and multiply
Disease
Deviation from health
Infectious disease
Pathologic state caused directly by microorganism of their products
(T/F) Even organs, tissues and their fluids have microbes
False, organs and tissues are microbe-free
Which factors would promote progression of an infection?
Proper portal of entry
No previous exposure to his infection
Host immunosupression
What happens to the microbes that remain in our body? Are they harmful?
They develop a complex relationship with the human host in which they can survive and not be harmful to the host
Microbial antagonism
Generally antagonistic effect “good” microbes have against intruder microorganisms. (Provide defense against disease-causing organism)
What is normal biota to a healthy host with functioning immune system?
Benefitial, or at worst commensal
(T/F) Humans can be separated from our resident microbes at anytime and will do okay.
False, humans do not do well if separated from our resident microbes, at anytime of out lives
What is a factor that can weaken host defense and increase susceptibility to infection
Physicial and mental stress
What is the difference between a true pathogen and opportunistic pathogen.
True pathogens cause disease in a healthy individual, whereas opportunistic pathogens typically cause disease in an immunocompromised host
It was recently discovered placenta harbors a small but significant number array of bacteria. What does this indicate?
This indicates that their intestines are colonized in the uterus
What is the most important source of microbiota for a newborn?
Its trip through the vagina
What enzymes provides the baby with the necessary enzymes to digest milk?
Lactobacillus
(T/F) Human milk contains around 600 species of bacteria and sugars the baby can digest
False, the baby can’t digest any of this but can be digested by healthy gut bacteria
Pathogenicity
Organism potential to cause disease
True pathogens
Capable of causing disease in healthy persons with normal immune defenses
Opportunistic pathogens
Cause disease when the host’s defenses are compromised or when the pathogen become established in a part of the body that is not natural to them
Virulence
Degree of pathogenicity
Virulence factor
Any characteristic or structure of the microbe that contributes to its ability to establish itself in the host and cause damage
Majority of infections are
Polymicrobial
Portals of entry
Route that a microbe takes to enter the tissue to cause infection
Exogenous
Microbe originating from outside source
Endogenous
Microbe already existing in the body (normal biota or a previously silent infection)
Do pathogens enter through the same portal of entry?
No, they use specific portals of entry
Which agents can enter through the skin, urogenital tract, and the respiratory tract
Streptococcus and Staphulococcus
Infectious dose
Minimum number of microbes necessary to cause an infection to proceed
Adhesion
Process by which microbes gain a more stable foothold on host tissues
What happens when there is a breach at a portal of entry
The respiratory tract is lined with cilia, which sweeps back and forth to move particles so that they can be swallowed rather than remain in respiratory tract.
Examples of adhesion mechanism
Fimbriae, surface protein, etc.
Phagocytes
Cells that engulf and destroy host pathogens by means of enzymes and antimicrobial chemicals
Antiphagocytic factors
Virulence factors used by some pathogens to avoid phagocytes
Leukocidins
Kill pathogens outright
(T/F) Bacteria can’t survive inside the phagocytes
False, some bacteria can survive inside the phagocytes
How can microorganism cause damage to their host?
By action of
enzymes
toxins
host’s defenses to respond excessively or inappropriately
Exoenzyme
Enzymes secreted by microbes that break down and inflict damage on tissues
Examples of exoenzymes
Mucinase, hyaluronidase, coagulase
Mucinase
Digest the protective coating on mucous membranes
Hyaluronidase
Digest the ground substance that cements animal cells together
Coagulase
Causes clotting of blood or plasma
Toxin
Specific chemical product of microbes that is poisonous to other organisms.
Hemolysins
Class of bacterial exotoxin that disrupts the cell membrane of red blood cells
What does hemolysins cause?
It causes RBC to hemolyze
Endotoxin is also known as? What is it?
Lipopolysaccharide (LPS). Is part of the outer membrane of gram-negative cell walls.
What does endotoxin causes?
Fever, inflammation, hemorrhage, diarrhea and DIC
Acute infections
Infection comes on rapidly, with severe but short-lived effects
Chronic infection
Infection that progresses and persist over a long period of time
Sign
objective evidence of disease as noted BY AN OBSERVER
Symptom
subjective evidence of disease as sensed BY THE PATIENT
Syndrome
A disease identified by COMPLEX SIGNS OF SYMPTOMS
Which of the following is not thought to weaken host defenses?
a. extremes in age
b. underlying disease states
c. surgery
d. moderate exercise
Moderate exercise
How does the earliest symptoms of disease result from?
By activation of the body defense of INFLAMATION
Signs of inflammation
Edema, granulomas (immune cells), lymphadenitis
Leukocytosis, leukopenia, septicemia, and bacterimia are signs of
Inflammation
Infections that go unnoticed are also called
Asymptomatics, subclinical, or inapparent
Portal of exit
Shed through secretion, excretion, discharge, or sloughed tissue
(T/F) Pathogens use a different portal to enter and exit
False, portal of exit are the same as portal of entry, but some pathogens use a different route
Latency
Dormant state of microbes in certain chronic infectious disease
Sequelae
Long-term or permanent damage to tissues or organs caused by infectious disease
Incubation period
Agent is multiplying but has not caused damage to elicit symptoms
Prodomal stage
Vague feeling of discomfort
Acute phase
Infectious agent multiplies at high levels
Covalescent period
Many patient stop taking antibiotics during this period, even though pathogens are still in their system leading to antibiotic resistance
Continuation phase
Only some infections have this phase. Either the organism lingers for months, years, or indefinitely after patient is well or organism is gone but symptoms continue
Reservoir
Primary habitat where pathogen originates
Transmitter
Individual or object from which and infection is acquired
Carrier
Individual who inconspicuously (not knowing) shelters a pathogen
The majority of animal reservoir agents are
Arthropods
Biological vector
Actively participates in a pathogen’s life cycle
Mechanical vector
Carries the microbe more or less accidentally on its body parts
Zoonosis
An infection indigenous to animals but naturally transmissible to humans
How is zonotic spread promoted?
By close association between humans and animals
How are microbes that thrive in the soil and water called? Can they cause harm?
They are called saprobic and cause little harm and considerable benefit to humans
Communicable disease
Host can transmit infectious agent to another host
Contagious disease
Disease is highly communicable
Noncommunicable disease
Compromised person is invated by their own microbiota
Horizontal transfer
Disease is spread through a population from one infected individual to another (strangers)
Vertical transfers
Disease is transmitted from parent to offspring (through placenta, milk)
Formite
Inanimate object
Healthcare-associated infections are also called
Nosocomial infections
Nosocomial infections are
Infectious diseases acquired or developed during a hospital stay or health care facility stay
What can promote nosocomial infections?
Devices such as catheres, prosthetic heart valves, grafts, drainage tubes, and tracheostomy tubes from ready portals of entry
Most common HAIs
Urinary tract infections
Infection control officer
Implements proper practices and procedures, tracks potential outbreaks, identifies breaches in asepsis, and trains health care workers in aseptic techniques
Etiologic/causative agent
The cause of infection and disease
Prevalence
Total number of existing cases in a given poulation
Incidence
The number of new cases over a certain time in period
Point-source epidemic
Infectious agent came from a single source, and all of its “victims” were exposed to it from that source (pot luck dinner)
Common-source epidemic
Result form common exposure to a single source of infection over a period of time (restaurant)
Propagated epidemic
Result from infectious agent that is communicable from person to person (flu, COVID)
Index case
First patient found in an epidemiological investigation
Endemic
Infectious disease that exhibits a relatively steady frequency over a long time period in a particular geographic locale (lyme)
Which of the following would promote progression of an infection?
a. low microbial virulence
b. proper portal of entry
c. genetic profile of host resistance to microbe
d. no previous exposure to this infection
b,c,d
which of the following factors is not thought to weaken host defenses?
a. extremes In age
b. underlying diseases states
c. surgery
d. moderate exercise
Moderate excercise, everything else weakens host defenses.
A patient is found to have a dental abscess. Antibiotic therapy is initiated to prevent spread of the infection to other tissues. If it does spread, what type of infection is it?
a. focal infection
b. primary infection
c. secondary infection
d. mixed infection
Focal infection
A client has 3 days of antibiotic treatment remaining. The client would be in which stage of infection?
a. acute phase
b. covalescent period
c. incubation period
d. prodomal stage
Covalescent period
