W2 interaction between microbe and host

Question 1

normal flora

Answer 1

covers body surfaces exposed to external environment and they are protective because they take up all the space
they are consistent at a given site but varies from site to site
large intestine has e.coli
upper respiratory track has streptococcus

Question 2

what can make normal flora harmful

Answer 2

excessive moisture

antibiotic use

Question 3

contamination

Answer 3

microorganism that is introduced where its not expected there is no growth yet therefore no damage

Question 4

colonization

Answer 4

growth after contamination there is still no damage

Question 5

DISEAse or infection

Answer 5

damage due to colonization
infection means the host is invaded there is still no signs yet
disease the host is invaded and injury is evident this occurs when symptoms begin

Question 6

ex of colonization

Answer 6

bacteria occasionally grow on bladder mucosa with no harm

Question 7

ex of infection

Answer 7

tb is growing in wbc but not yet causing harm

Question 8

pathogen

Answer 8

causes disease

Question 9

etiology

Answer 9

cause of disease

Question 10

virulence and virulent factors

Answer 10

degree of pathogenicity
virulent factors increase the ability to cause disease
-enzymes that dissolve hyaloric acid (tissue cement)
-enzymes that destroy rbc so that iron is for bacteria
-slimy capsules around bacteria that prevent phagocytic abc from engulfing them

Question 11

non pathogenic

Answer 11

can’t cause disease

Question 12

low grade pathogens

Answer 12

don’t cause disease under most circumstances, they are opportunistic, they cause disease when the immune system is compromised.
ex. e.coli aren’t harmless until introduced to an are like bladder where they cause disease

Question 13

what is a bacterial toxin

Answer 13

causes damage to sites far removed from initial infection site
exotoxin is usually gram positive and it is released from initial bacteria, carried by blood to specific tissue
endotoxin-usually from gram negative bacteria and it is in the cell wall, it is released when bacteria cell disrupted and it is a generalized effect such as fever malaise and decrease in blood pressure, this can be from antibiotics

Question 14

chain of infection

Answer 14

3 elements required for transmission-outbreak cycle
1. source, 2.. transmission 3. susceptible host they all overlap to create the biohazards symbol.
to break the chain you must eliminate one element, stop source eliminate transmission or reduce susceptibility through handwashing immunizations, ppe, sterilization.

Question 15

reservoirs

Answer 15

this is the source
human reservoir
the human body is the most common source and these people are known as CARRIERS they are harbouring pathogenic organism with no sign of infection this is the early most infectious stage and the carrier does not have any symptoms, this is the incubation period.
animal reservoir– called zoonoses found in animals and transmitted to humans- like salmonella
non living reservoir-soil or water
**moist environments in healthcare wet sinks and flowers

Question 16

convalescent carrier

Answer 16

recovered but still carrying disease

Question 17

chronic carrier

Answer 17

convalescent carrier for more than 6 months

Question 18

transmission

Answer 18

3 possible ways

contact-direct, indirect and droplet
direct is person to person
indirect is person thing person
droplet is close proximity to someones fluids

vehicle-food/water/air it transmit live microbe** uncommon in clinical setting.
–droplet nuclei means its in air for more than 1 meter or a long time

vector-insect one host to another for example mosquitoes with malaria not common in hospital

Question 19

susceptible host

Answer 19

someone will encounter microbe resulting in disease, factors related to health and age
ex: newborns highly susceptible because of low exposure and immature immune system, even therapeutic measures like chemo surgery and catheters can make people more susceptible.

Question 20

portals of entry

Answer 20

skin- hair follicle, sweat gland **broken skin or very moist skin
mucous membrane in respiratory tract, gastrointestinal tract, or genitals
-placenta- filter moms blood only a few like AIDS, hep B and rubella can get through
parental-introduction bipasses gastrointestinal tract-intramuscular and intravenous

Question 21

signs and symptoms of infection

Answer 21

fever- increase in temp of 1 degrees celsius also known as pyrexia BLOOD VESSELS CONSTRICT increase metabolism and shivering the skin is cold, when the fever breaks people sweat.
lymph node swelling- microbe from tissue trapped in lymph node or multiplication of lymphocyte. cervical lymph node in neck axillary lymph node in armpit and inguinal lymphnode in groin
inflammation- host cells invaded release histamine and this initiates inflammation– heat red pain swell histamines cause vasodilation and increased permeability of blood vessels so fluid goes into tissue and phagocytic white blood cells can get there–antibodies travel there too as well as platelets to surround microbes.

Question 22

purulent exudates

Answer 22

plus and this is phagocytic abc that are dead

Question 23

acute disease

Answer 23

symptoms develop rapidly and go away rapidly like a cold

Question 24

chronic disease

Answer 24

symptoms develop slowly and are slow to go away

Question 25

latent disease

Answer 25

periods of inactivity before or during herpes

Question 26

localized infection

Answer 26

confined to one area- step throat.

Question 27

septicemia

Answer 27

presence of multiple pathogens in blood

Question 28

focal infection

Answer 28

confined to one area but pathogens or toxins move to a new area

Question 29

bacteremia

Answer 29

bateria in blood, not multiplying just hitching a ride

Question 30

viremia

Answer 30

presence of virus in blood but not multiplying just hitching a ride

Question 31

exogenous infection

Answer 31

cause infection from outside of body

Question 32

endogenous infection

Answer 32

cause of infection from inside of body, e.coli from intestine makes way to urinary tract resulting in utility

Question 33

primary infection

Answer 33

infection previously healthy person

Question 34

secondary infection

Answer 34

infection that immediately follows a primary infection
ex: secondary bacterial infection following primary viral infection, pneumonia after the flu or a yeast infection after antibiotics

Question 35

nosocomial infection

Answer 35

acquired when patient in hospital or health care associated infection HCAI
5-15% of all hospital patients acquire one (also depends on population)

Question 36

factors of nosocomial infections

Answer 36

-hospital microorganism bacteria brought to hospital and all but antibiotic resistant bacteria are killed off
-immunodefficient patient-weakened immune system due to treatment or condition
defective mean is different it means that b or t cells don’t work
-transmission- easily due to close proximity and also OPENINGS FROM SURGERY ARE MOST COMMON

Question 37

what are antibiotics

Answer 37

• produced by microorganisms like funds and it inhibits bacterial growth or kills bacteriA
• inhibit the cell wall synthesis or protein synthesis
• penicilen discovered by alexander flemming in 1928

Question 38

antibiotic susceptibility testing

Answer 38

this is used to choose which antibiotic is going to be used for treatment
the bacteria allowed to colonize agar plate and paper discs soaked in antibiotics are placed around plate and this culture is interpreted.
if clear area around disc- antibiotic effective
if bacteria grow right to disc its not effective

Question 39

antibiotic resistant organisms or aro

Answer 39

multi drug resistant organisms called mdro
secondary antibiotic required, and the y are less effective they are difficult and expensive to treat and patients must be isoleted
ex: MRSA VRE

Question 40

modes of resistance

Answer 40

some naturally become resistant

• over prescription causes the resistant bacteria to thrive and increases the likely hood for them to evolve
• people stop taking antibiotics and this makes the strong ones survive
• mutation-makes them resistant all regular bacteria die and the resistant ones to colonize
• -conjugation resistant bacteria and harmless bacteria share genes

Question 41

MRSA

Answer 41

-spread in healthcare setting and transmitted by direct contact.
MRSA difficult to eradicate from an institution and increases patient mortality
prevention -identify cases and screen swab everyone coming in
-isolate case
-identify carriers either staff or patients
-eradicate MRSA from carriers

Question 42

vancomycin resistant enterococcus

Answer 42

VRE
in normal bowel flora and if they get into urinary tract its a low grade pathogen with no real threat if individual is healthy
they are resistant to all drugs and untreatable so it can be fatal and it is mostly spread in a hospital setting
to combat this hospitals restrict the use of antibiotics and use rigorous hygiene procedures.

Question 43

clostridium difficle

Answer 43

CDAD
spore formed in intestine
following antibiotic therapy, with vancomycin the normal flora decreases and the spore is able to vegetate and it produces a toxin which effects the intestinal wall and sometimes causes death, an indicator of this is water stool

Question 44

miscellaneous modes of controlling infection

Answer 44

silver has antibacterial qualities and is put in bandaids catheters and clothing
phages are viruses that infect bacteria

Question 45

infection prevention and control programs-what do they do

Answer 45

• surveillance and analysis of nosocomial infections
• surveillance of antibiotic resistance
• investigate control of outbreaks
• implement and monitor preventative measures
• education
• policies
• consult with epidemiologists they study the incidents, source and spread of disease