INFC 215 Mod 2 Flashcards
What are the three things that make up the chain of infection? (R, T, H)
- Source of infection (reservoir)
- Means of transmitting the microbes
- The susceptible host
When can the chain of infection be stopped?
The chain of infection can be stopped at any time
What are the 3 reservoir for infectious microbes?
1.Humans
2. Animals
3. Non living things
What do we call a human reservoir/ person harboring pathogenic organism?
A carrier
Define zoonosis
A disease found on an animal but may be transmitted to humans
Why are carriers more dangerous than an infected person?
Carrier is more dangerous because they might not know that they are carrying dangerous micro organism
Define convalescent carrier
When a person has recovered from a disease, but are still carrying the infectious organisms
Define chronic carrier
When a person has recovered and is still carrying around the infectious organism after 6 months
What are two examples of non living reservoirs?
Water and soil
Name 2 disease caused by non living reservoirs and define what they are
- Botulism - food poisoning
- Tetanus - Spores introduced to human tissues in low/ no oxygen environment
Why is it important to eliminate moist environments in hospitals?
Bacteria will grow in most moist environments
Name and define the 3 principle routes for transmission of infectious microbes (C,V,V)
- Contact - can be done with direct, indirect contact or droplet transmission
- Vehicle - transmission of infectious microbes with an agent like food, water, air, blood or medication. With vehicle transmission it is common for several of people to get sick at the same time
- Vector - insects that carries infectious organisms from one host to another (example: mosquitoes)
What are the four factors that influences host susceptibility?
- Age
- Health
- Immune status of an individual
- Dose of infectious agent individual was exposed to
How can an individual become a less susceptible host against a disease causing microbe?
By either recovering against the infection or getting a vaccination against the microbe
What are the 4 portals of entry for infectious micro organism? (S,M, P, P)
- Skin via hair follicles or sweat glands if skin is moist
- Mucous membrane - includes the respiratory, gastrointestinal and genital tracts.
- Placenta - only a few can pass through - rubella virus/ German measles, viruses causing hepatitis B and AIDs
- Parental route (think poke) - micro organisms/ contaminated punctures, bites, cuts, surgical wounds and trauma injuries that enter/ intravenous or intramuscular injection that by pass the gastrointestinal tract
What are disease recognized by?
Signs and symptoms. Each disease has its own signs and symptoms
Define signs
Is observed by examining the patient.
Define symptoms
Characteristics of the disease that can only be observed or felt by the patient
What happens if infectious micro organisms get pasts the human body defenses?
The mucous membrane, acids of the digestive system and a number of indication (fever, lymph node swelling and inflammation) occurs
Define fever/ pyrexia
It is when the body temperature increases + 1 degree Celsius
What does getting a fever do? (3 things)
- Increases the body temperature by 1 degree Celsius
- Speeds up metabolic rate in body cells
- May facilitate phagocytosis (white blood cells eating up infectious cells) and tissue healing
How can one monitor a patient’s conditions?
Measure their fever; fever is one of the few measurable signs
What is the lymphatic system?
It is a series of vessels that drains fluid from tissues, passes through lymph nodes and returns it to the blood stream
Name 2 reasons why lymph nodes swell during infections
- Microbes from tissue fluid are being trapped in a lymph node. Microbes can then multiply and cause infection
- Multiplication of lymphocytes (responsible for immunity) which are located in lymph nodes
What does one single swollen lymph node mean?
One infected lymph node
What does multiple swollen lymph node mean?
Immune system responding to the micro organism
What are the 3 locations where the lymph nodes are closest to the skin and what are the nodes called?
- Neck –> Cervical nodes
- Under arms –> axillary nodes
- Groin area –> inguinal nodes
What is the chemical that gets released and starts inflammation when micro organisms are invading?
Histamine
What are the 4 signs of inflammation?
- Heat
- Pain
- Swelling
- Redness
What causes the heat and redness when inflammation happens?
Histamine happens with vasodilation (blood vessels widening) which increases blood flow to injured site.
What causes swelling and pain when inflammation happens?
Histamine increases permeability of blood vessels and fluid leak from vessels to surrounding tissues
What are the 4 steps inflammation help host of clearing infectious micro organisms?
- Increased number of white blood cells get attracted to the area.
- The white blood cells then produce antigens to activate antibodies.
- The antibodies then coat the bacteria in preparation for phagocytosis / neutralizes the toxins.
- Clotting elements from blood also move to injured site to surround and isolate microbes.
What are 2 infection signs that result from inflammatory response?
- Purulent exudate: Is pus/ white blood cells that died in action
- Leukocytosis: Increased number of white blood cells
Which part of the human body are sterile?
Tissue, blood, cerebrospinal fluid
Define normal flora
Are micro organisms that live on that part of the body and do not produce disease in normal circumstances
Do different body sites have the same normal flora?
No, different body sites have different normal flora (ex. the normal flora in the mouth is different than the normal flora on the skin)
Which part on the human body has the greatest normal flora?
The large intestine
Do 2 different people have the same normal flora in their mouths?
Yes
What are the 2 factors that affect normal flora?
- Excess moisture on skin
- Antibiotics use alters normal flora
Define contamination
Micro organism introduced to an unexpected body site. There is no growth to the microbes and there is no damage to the microbes
Define infection
Host has been invaded with an organism and there are no signs of host injuries
Define disease
Host has been infected with micro organism and damage has been done to the host
Define pathogen
Disease causing organism
Define etiology
The cause or origin of the disease - normally caused by an organism
Define virulence and what are the factors of virulence?
Degree/ factors a micro organism has. The more virulence factor a micro organism has the more likely a disease will occur
Virulence factor includes enzymes to dissolve tissues, substances that destroy red blood cells/ white blood cells, capsules or slimy coatings which prevents white blood cells to destroy the micro organism
Define non pathogen
Organisms that cannot cause a diease
Define low grade pathogens/ opportunistic pathogens
Organisms that are non pathogenic for the most part but will cause a disease when host’s defense are lowered
What are the 2 types of bacterial toxins that damage initial site of infection?
Exotoxins and endotoxins
How are exotoxins produced?
Exotoxins are produced by Gram positive bacteria and are carried AWAY from the infected site by blood
What do exotoxins target/attacks?
Exotoxins target/attacks a specific tissue in the human body
How are endotoxins produced?
Endotoxins are made by Gram negative bacteria and are released when bacterial cells are disrupted
What do endotoxins target/ attack?
Endotoxins have a generalized effect on the target. Endotoxins can cause fever, general malaise/ aches and life threatening effects
Why is the use of antibiotic cause complications with endotoxins?
Antibiotics will destroy bacterial cells and as a result more endotoxins get released which can cause a shock
Define acute disease
Symptoms develop rapidly and disease runs its course quickly
Define chronic disease
Symptoms develop slowly and disease slowly disappear
Define latent disease
Periods of inactivity before symptoms appear or between attacks
Define localized infection
Confined to one area of the body
Define focal infection
Confined to one area but pathogens / their toxins migrate to other areas
Define systemic infection
Pathogens spread to more than one organs or tissues
Define septicemia
Pathogens that are present in the blood and are multiplying
Define bacteremia
Bacteria in the blood but not multiplying
Define viremia
Viruses in the blood but are not multiplying
Define toxemia
Toxins in the blood
Define exogenous infection
Microbes that come from outside of the host
Define endogenous infection
Microbes that comes from within the host’s body
Define primary infection
Infection of a previously healthy person
Define secondary infection
Follows a primary infection and is caused by a different microbe
What are nosocomial infections?
Are infections acquired during stay at a hospital or health care facilities
What is the rate of getting nosocomial infections?
5 - 15 %; rates differ depending on the type of hospital
What is one thing that can be done to reduce death from nosocomial infections?
Keeping good hand hygiene
Name 3 factors that contribute to nosocomial infections (MO, I, T)
- Hospital micro organism - Antibiotic resistant strain of bacteria survive in the hospital making bacteria reservoir dangerous
- Immunodeficient - patients in the hospital do not have a well functioning immune system
- Transmission - bacteria can be transmitted to patients because patients are in close proximity, hospital staff visiting multiple of patients
Name 3 common nosocomial infections
- Urinary tract infections
- Surgical wounds infections
- Pneumonia
What are staph carriers?
Hospital staff that can carry bacteria in their nasal passages with no symptoms or infections
How can hospital staff prevent themselves from being staph (staphylococus aureus) carriers?
Keep hands away from nose and wash hands after coughing, sneezing and blowing nose
How are antibiotics made?
Antibiotics are made from a micro organism that will inhibit the growth or kill another micro organism
Do all antibiotics at the same way?
No
True or false: A few bacteria have a predictable sensitivity pattern
True
What is required to see if the microbes are sensitive / resistant to the antibiotics?
Antibiotic susceptibility / sensitivity testing
List the 5 steps done in antibiotic susceptibility/ sensitivity testing
- Organism is isolated/ identified
- Organism gets spread over an agar plate surface
- Paper discs soaked in different antibiotics get placed on the plate
- Plate gets incubated overnight
- Plate gets examined
When examining a susceptibility/sensitivity plate, what does a clear antibiotic disc and an unclear antibiotic disc mean?
Clear disc = micro organism is susceptible to the antibiotics
Unclear disc = micro organism is resistant to the antibiotics
What is the difference between a host and a carrier?
A carrier is someone who harbors pathogenic organism but has no signs of infection. A host is a person that the organism is transmitted to
What are antibiotic resistant organisms (AROs)/ multidrug resistant organisms (MDROs)?
These are organisms that were previously treated with the best antibiotic but are now resistant to that drug
Why are antibiotic resistant organisms/ multidrug resistant organisms a concern?
Because they severely limit the choice of effective antibiotics
Why are second choice antibiotics not as good as first choice antibiotics?
Second choice antibiotics are not effective as first choice antibiotics and can be more toxic and more costly
What do patients with antibiotic resistant organisms/ multidrug resistant organisms have to do in health care facilities?
They are isolated and precautions are taken when working with patients with AROs/ MDROs
Name 3 alarming AROs/ MDROs/ super bugs in health care facilities and what kind of illness they cause
- MRSA (methicillin resistant staphylococcus) - causes skin infections
- VRE (vancomycin resistant enterococcus) - causes urinary tract infection
- CDAD (clostridium difficile) - causes watery unformed stool
Why is it important to prevent the spread of superbugs in health care facilities (3 reasons)?
- They are difficult to remove
- They increase patients’ mortality (death) and morbidity (illness)
- They increase patients’ length of stay and cost of care
What are the 4 steps to prevent MRSA?
- Identify cases - screen all
- Isolate cases
- Identify carriers amongst patients and staff by nasal swab
- Eradicate MRSA with intranasal mupirocin and disinfectant soaps
What are 4 factors that led to the development of drug resistant bacteria?
- Over prescription of antibiotics - medication that are over used even if it is not bacterial related
- People that stop taking antibiotics because they have no more symptoms and some bacteria are still alive. This is bad because what is left are the strongest bacteria
- Mutation - when a harmful bacteria with a mutation survives the antibiotics
- Conjugation - Drug resistant from a harmless bacteria could be transformed to harmful microbes. The harmful microbe then conjugates with other harmless microbe until a resistant colony is formed.
What is the biggest worry for bacterial strains?
The biggest worry is that bacterial strain will develop and be resistant to all antibiotics
What are the 2 ways to control infections?
- Silver - silver has antibacterial property
- Phages - are good viruses (don’t harm humans or animals) that can infect certain bacteria
