Chapter 14 Micro Flashcards
1
Q
what is a pathogen?
A
disease causing microorganism
2
Q
Infection means what?
A
colonization of the body by pathogens
3
Q
disease
A
abnormal state which the body is not functioning normally
4
Q
what is pathogenesis?
A
development of the disease
5
Q
etiology can be defined as what?
A
the cause of a disease
6
Q
Few microorganisms are pathogenic. True or false?
A
TRUE!
7
Q
what is the importance of normal microbiota?
A
permanently colonize the host starting at birth and later through food and contact with others
8
Q
how are microbiota studied and what is the benefit?
A
DNA sequencing to make microbiome.
Determining microbiome can help with specific syndrome or disease correlation
9
Q
why might different types of bacteria colonize different parts of the body?
A
- Nutrient availability (secretion, excretions and dead cells
- physical and chemical factors (pH and temp)
- defenses of the host
- mechanical factors (chewing, flushing, mucus and cilia)
10
Q
what are transient microbiota?
A
only present for a short period of time, typically coming from the environment and do not cause disease.
11
Q
when can transient microbiota cause disease?
A
when it displaces the normal microbiota
12
Q
list some factors that contribute to differing microbiota in each person:
A
age diet stress climate lifestyle occupation emotional state health status
13
Q
where does normal microbiota reside?
A
skin conjunctiva nose throat mouth large intestine urinary tract reproductive system
14
Q
normal microbiota of the skin:
A
most microbes do not become direct residents due to oil and sweat on skin’s surface. low moisture content
15
Q
what is keratin’s role in the normal microbiota?
A
serves as barrier; low pH of skin inhibits many microbes
16
Q
normal microbiota of conjunctiva:
A
contains nearly the same microbiota found on the skin’s surface
17
Q
what are some defenses of the conjunctiva to prevent microbe colonization?
A
tears and blinking
18
Q
normal microbiota of nose and throat:
A
microbial antagonism reduces potential pathogens from causing disease
19
Q
what are some defenses of the nose and throat to prevent colonization?
A
nasal secretions kill and inhibit many microbes
mucus and ciliary action remove microbes
20
Q
normal microbiota of the mouth:
A
moisture, warmth and constant presence of food make the mouth an ideal environment that supports large diverse microbial populations
21
Q
what are some defenses of the mouth?
A
biting, chewing, tongue movements and salivary flow dislodge microbes
22
Q
normal microbiota of the urinary and reproductive systems:
A
mucus and shedding of the lining prevent microbes from attaching
Flow removes microbes
cilia and mucus expel microbes from the cervix
23
Q
what are defenses of the urinary and reproductive tract to prevent microbe colonization?
A
- acidity of the vagina inhibits or kills microbes
- urea and low pH of urine are antimicrobial
24
Q
normal microbiota of the large intestine:
A
contains largest numbers of the resident microbiota in the body because of moisture and nutrients
25
what are defenses of the large intestine to prevent microbe colonization?
- mucus and regular shedding of the lining prevent many microbes from attaching to the lining of the GI tract
- mucosa produces several antimicrobial chemicals
26
microbial anatogonism
competition between microbes
27
how does the normal microbiota use microbial antagonism?
competing for nutrients
producing substances harmful to invaders
changing conditions such as pH and O2
28
explain germ free animals
raised in lab but have underdeveloped immune systems and are more susceptible to pathogenic infection
require more calories and vitamins than normal animals
29
what happens when germ free animals are repopulated with microbiota from obese animals?
they become obese
30
why are germ free animals used?
help investigate host microbe interactions that promote health
31
PRObiotics are described as what?
live microbes that are applied or ingested to the body for beneficial effects
32
PREbiotics are describes as what?
chemicals that selectively promote growth of beneficial bacteria
33
what is the purpose for the FMT (fecal microbiota transplant)?
process of transplantation of fecal bacteria from healthy donor to recipient, can help with C. diff
34
What are the three types of symbiosis?
commensalism, mutualism, parasitism
35
what is commensalism?
one organism benefits and the other is unaffected
| Example: S. epidermia inhabit surface on skin
36
what is mutualism?
both organisms are benefiting
Example: E.coli: bacteria in the large intestine that synthesizes vitamin K and some B vitamins; they're absorbed into the bloodstream and distributed for use by body cells. In exchange, the large intestine provides nutrients used by the bacteria, allowing them to survive
37
what is parasitism?
one organisms benefits at the expense of the other like pathogens
Example: influenza
38
opportunistic pathogens are what?
when pathogens that normally inhabit other areas gain access to other body sites it can be detrimental in immunocompromised people
39
what are the three ways normal microbiota protect the host?
1. occupy niches that pathogens might occupy
2. lower ph by producing acids
3. produce bacteriocins that kill other bacteria
40
what does etiology mean?
the cause of diseases or conditions
41
what are Koch's postulates?
1. same pathogen must be present in every case of the disease
2. pathogen must be isolated from the diseases host and grown in pure culture
3. pathogen from pure culture must cause the disease when it is inoculated into healthy lab animal
4. pathogen must be isolated from inoculated animal and must be shown to the original animal
42
why is paying attention to Koch's postulates important?
correlation does not mean causation
43
what are some problems with Koch's postulates?
1. some organisms cannot be cultured on artificial media
2. some diseases types can be caused by multiple different pathogens
3. some pathogens cause multiple diseases
4. some carriers are asymptomatic
5. some pathogens cause symptoms or leave tell tale signs that no other pathogen can produce, implicating it in the disease
44
what are the 3 ways to classify infectious diseases?
- signs and symptoms
- syndromes
- contagious, communicable, noncommunicable
45
what is a symptom?
change in body function that is felt by patient as a result of disease
Example is malaise
46
what is a sign?
change in body that can be measured or observed as result of disease, swelling, fever or paralysis
Examples is high cholesterol
47
what is syndrome?
specific group of signs and symptoms that accompany a disease
Examples: down syndrome, Parkinson's syndrome, AIDS
48
contagious disease is classified as what?
disease that is easily spread from one host to another , does not require close contact
49
communicable disease is classified as what?
disease that is spread from one host to another either directly or indirectly, requires close contact
50
noncommunicable disease is classified as what?
disease that is not transmitted from one host to the other
51
give examples of contagious disease:
Influenza, measles, common cold
52
give examples of communicable disease:
ebola, HIV/AIDS, hepatitis
53
give examples of noncommunicable disease:
tetanus, food poisoning, lyme disease
54
COVID-19 is both:
contagious and communicable
55
what is incidence?
number of new cases of a disease over specific time period
56
what is prevalence?
existing cases of new disease at a given time
| incidence x time) -(deaths +cures
57
what is sporadic disease?
disease that occurs occ. in pop
58
what is endemic disease?
disease constantly present in population
59
what is epidemic disease?
disease acquired by many hosts in given area in short time
60
what is pandemic disease?
worldwide disease (COVID, Influenza in 1918)
61
herd immunity
when many people in pop. are immune, others are protected from the spread of infection as consequence
62
what is acute disease?
symptoms develop rapidly, lasts short time
| example: flu
63
what is chronic disease?
disease develops slowly and continues or recurs for a long time
example: encephalitis
64
what is subacute disease?
symptoms between acute and chronic
| example: hepatitis
65
what is latent disease?
disease with period of no symptoms when the causative agents inactive
example: herpes
66
Covid-19 is an acute disease...
symptoms develop rapidly and last a short time
67
what is local infection?
pathogens that are limited to a small area of the body
68
what is systemic infection?
infection throughout the body via blood or lymph system
69
what is a focal infection?
infection that began as an asymptomatic infection in one place and causes distant injury to another part
70
what is focal infection theory?
distant from infections that spread from one place to another because infection is known and symptomatic
71
what is bacteremia?
bacteria in the blood
| Example: can arise from teeth brushing and dental work
72
what is septicemia?
growth of bacteria in the blood
73
what is sepsis?
toxic inflammatory condition arising from spread of microbes, especially bacteria or their toxins from focus infection
74
what is toxemia?
toxins in the blood
75
what is viremia?
viruses in the blood
76
what is a primary infection?
acute infection that causes the initial illness
77
what is a secondary infection?
opportunistic infection that occurs after a primary infection. It may be a result of the primary infection or the treatment of the primary infection
78
what is a subclinical or asymptomatic disease?
no noticeable signs or symptoms (inapparent infection)
79
what is case fatality rate?
is the ratio of deaths to the total number of cases of a specific disease for a certain period of time
80
what are some general disease susceptibility factors?
```
climate
nutrition
lifestyle
age
sex
fatigue
inherited traits
chemotherapy
```
81
what is incubation period?
Interval between infection and signs or symptoms, able to spread infection
In covid: 4-14 days
82
what is prodromal period?
early, mild symptoms
| In COVID: fever, loss of smell/taste, headache
83
what is period of illness?
most severe, death possible, (white cells can go up or down)
| In COVID: ICU admission, death possible
84
period of decline means what?
getting better, vulnerable to secondary infections
85
period of convalescence is what?
return to normal health, spread of infection still possible
86
what are reservoirs?
Continual sources of infection
Pathogen has resources for survival and opportunity for transmission
*can be living or nonliving
87
what is zoonoses?
diseases transmitted by animals to humans
88
what are infected individuals?
carrier signs and symptoms of disease as a human reservoir
89
what are carriers?
inapparent infections or latent diseases
90
what are different types of transmission?
contact transmission, vehicle transmission, vector transmission
91
what is waterborne transmission?
transmission by inanimate reservoir i.e water
| sewage in H20 cholera
92
what is vehicle transmission?
transmission by inanimate reservoir
93
what is food-borne transmission?
transmission by an inanimate reservoir
| incomplete cooking or storage of food leading to contagion
94
what is airborne transmission?
transmission by inanimate reservoir
| must be through air more than one meter away
95
how can a person have transmission by zoonoses?
direct by animal-animal
contact with animal products
contaminated non living objects
ingestion
96
what is direct transmission?
requires close association between infected and susceptible host
97
what is indirect transmission?
spread by non living objects like fomites
98
what are droplets?
transmission by proximity to large infectious agent containing droplets less than 1 meter away
99
what is biological transmission?
active, pathogen reproduces in vector
100
what is mechanical transmission?
passive, arthropod carries pathogen on feet or body
101
what are nosocomial infections?
acquired in the hospital
102
what are some contributing factors to nosocomial infections?
compromised host, disease, wounds, burns, sedation, chemotherapy, stress, malnutrition
103
how can nosocomial infections be controlled?
aseptic technique, hand washing, disinfection, sterilization, packaging or equipment, dressings
104
what are emerging infectious diseases?
diseases that are new, increasing in incidence or showing potential
105
factors that contribute to EID include?
mutation, reassortment,
evolution of new strains, changes in weather, ecological disaster, war, poverty, inappropriate use of pesticides or antibiotics
106
what are the different types of epidemiology?
descriptive: collection and analysis of data done retrospectively
Example: Snow, London cholera epidemic
analytical: comparison of diseases group and healthy group
Example: Nightingale comparing soldiers and civilians
experimental: controlled experiments
Ex: "Savior of mothers" Ignatz Sem.
107
what are case reporting and nationally notifiable diseases?
health care workers report specified disease to local, state and national offices
Physicians are required to report occurrence
108
what is morbidity?
incidence of specific notifiable disease
109
mortality
deaths from notifiable disease
110
morbidity rate
number of people affected in relation to total pop
111
mortality rate
number of deaths from disease in relation to pop
112
why do nosocomial infections generate?
-microorganisms in the hospital environment
-the compromised (or weakened) status of the host
-the chain of transmission in the hospital
The interaction of all 3 factors poses a risk of HAI, not just one alone
