BACTE (IMMUNITY) Flashcards
(99 cards)
1
Q
COLONIZATION
A
presence and multiplication of new microorganisms that may cause an infectious disease or eliminated by host defenses
2
Q
INFECTION
A
entrance and multiplication of a microorganism in or on a host
3
Q
INFECTIOUS DISEASE
A
an infection w/ functional and structural harm to the host that is usually accompanied by signs and symptoms
4
Q
PATHOgen
A
a microbe capable of causing a disease
5
Q
PATHOlogy
A
study of the structural and functional manifestations of a disease
6
Q
PATHOlogist
A
a physician specializing in pathology
7
Q
PATHOgenicity
A
the ability to cause a disease by overcoming host’s defenses
8
Q
PATHOgenesis
A
disease process
9
Q
Virulence
A
degree of pathogenicity
10
Q
Etiology
A
study of the cause/s of disease
11
Q
Reservoir
A
environment or place of origin of the infecting agent
12
Q
Measured by the number of organisms required to cause disease
A
VIRULENCE
13
Q
Quantitative measure of pathogenicity
A
VIRULENCE
14
Q
number of organisms needed to cause infection in half the hosts/population.
A
50% of infectious dose (ID50)
15
Q
number of organisms needed to kill half of the hosts/population.
A
50% of lethal dose (LD50)
16
Q
INFECTIONS (4 types)
A
NOSOCOMIAL INFECTION
COMMUNITY-ACQUIRED INFECTION
ENDOGENOUS INFECTION
EXOGENOUS INFECTION
17
Q
Acquired in the HOSPITAL or other health care settings
A
NOSOCOMIAL INFECTION
18
Q
Results from organisms from external sources
A
EXOGENOUS INFECTION
19
Q
Causative agent is present or incubating at the time of admission into the health care facility
A
COMMUNITY-ACQUIRED INFECTION
20
Q
Results from organisms that are part of the patient’s normal flora
A
ENDOGENOUS INFECTION
21
Q
Bacteria most often associated w/ nosocomial infections include:
A
Staphylococcus aureus
Escherichia coli
Enterococcus faecalis
Pseudomonas aeruginosa
22
Q
Most of these nosocomial pathogens are resistant to?
A
multiple antibiotics
23
Q
Bacillus anthracis is?
A
TRUE PATHOGEN
24
Q
Candida albicans is?
A
OPPORTUNISTIC PATHOGEN
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microorganisms (bacteria, parasites, viruses, fungi, PRIONS) capable of causing an infectious disease
PATHOGENS
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has the ability to infect a host w/ a healthy immune system as well as those in immunosuppressed state
TRUE PATHOGEN
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attacks a debilitated host but presents no danger to a healthy individual
OPPORTUNISTIC PATHOGEN
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Infections of the immunocompromised hosts that do not cause a disease in individuals w/ a normal immune system
OPPORTUNISTIC INFECTIONS
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Opportunistic infections are increasing due to:
Widespread use of broad-spectrum antibiotics that can alter normal flora
Increased use of immunosuppressive drugs (in organ transplantation)
Chemotherapeutic agents (cancer)
Increased and prolonged use of urethral catheters
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In immunosuppressive conditions, the host’s immune system is unable to effectively battle those microorganisms considered to be normal flora for the general population.
OPPORTUNISTIC INFECTIONS
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Individuals at risk for opportunistic pathogens include:
Dialysis patients, Individuals on heart pumps
Diabetics, burn victims
Those w/ chronic medical problems; those undergoing invasive medical procedures
Those w/ foreign body implants (heart valves, prosthetic devices, IV catheters)
Alcoholics and IV drug users
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Microorganisms normally residing in a particular body site; they do not usually cause an infection; also known as
usual or indigenous flora
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2 types of normal flora
Transient flora
Resident microbial flora
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Resident microbial flora
colonize an anatomical area for months or years
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Transient flora
temporarily present at an anatomical site
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Distribution of normal flora
Skin, Mouth and oral cavity, nasopharynx
Stomach and upper small intestine, colon
Urethra
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STERILE
no normal flora
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There are anatomical sites considered to be STERILE
BLOOD,
CEREBROSPINAL FLUID and
URINARY BLADDER
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Normal flora can become pathogenic if they are
moved to another site
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The slightly acidic pH (5.5-6.0) results from the presence of acids produced by its normal flora:
skin
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Common NF of skin
Staphylococcus spp.
Propionibacterium acnes
Micrococcus
Candida
Clostridium
Diphtheroids
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Less Common NF of skin
Streptococcus
Enterococcus
Acinetobacter
Bacteroides
Moraxella
Gram negative rods
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MOUTH & ORAL CAVITY normal flora
Viridans streptococcus
Staphylococcus epidermidis
Neisseria (non-pathogenic spp.)
Moraxella catarrhalis
Lactobacilli
Diphtheroids
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Anaerobic NF include:
Actinomyces
Veilonella
Bacteroides
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May serve as a site of asymptomatic carriage of several microorganisms
NASOPHARYNX
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Common NF of nasopharynx
Staphylococcus aureus
Staphylococcus epidermidis
Diphtheroids
Haemophilus parainfluenzae
Streptococcus
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Less Common Nf of nasopharynx
Streptococcus pneumoniae
Moraxella catarrhalis
Haemophilus influenzae
Neisseria meningitidis
Other Moraxella spp.
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maintain a reservoir for the organism but do NOT have an infectious disease BUT serve as an infectious source for others
Asymptomatic carriers
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Asymptomatic carriers have?
Staphylococcus aureus
Neisseria meningitidis
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Are usually sterile containing less than 1000 organisms/ml
STOMACH & UPPER SMALL INTESTINE
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Organisms entering the stomach are usually killed by?
HCl and gastric enzymes
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When organisms are passed in the small intestine, they may be destroyed by?
bile and pancreatic enzymes
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When the gastric pH increases to over 5.0, colonization from bacteria of oral, nasopharyngeal, or colon may occur
Lactobacilli
Bifidobacteria
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Heavily colonized and serves as a reservoir for infection for numerous body sites, including the urinary tract and peritoneal cavity
colon
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normal flora of colon
Bacteroides
Lactobacillus
Clostridium
Eubacterium
Coliforms such as Escherichia coli
Aerobic and anaerobic streptococci
Yeast
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Normal flora of the distal urethra in both males and females may contain:
Diphtheroids
Streptococci (alpha and non-hemolytic)
Peptococcus
Staphylococcus epidermidis
Bacteroides
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Nf of GUT:
Lactobacillus spp.
Bacteroides spp.
Clostridium spp.
Peptostreptococcus
S. aureus
S. epidermidis
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Environment or the place of origin of an infecting agent is referred to as the?
RESERVOIR
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RESERVOIR can be?
Humans, Animals
Water, food, air, soil
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Humans acquire microbial agents by various means referred to as
MODES OF TRANSMISSION
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MODES OF TRANSMISSION can be:
direct or indirect
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DIRECT
when the host directly contacts the microbial reservoir
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INDIRECT
when the host encounters the microorganism by an intervening agent
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The intervening agent can be a:
Vector – living entity
Vehicle/Fomite – non-living entity
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DIRECT TRANSMISSION
Congenital contact
Sexual contact
Hand-to-hand contact
Droplet infection
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May occur across the placenta or during passage at the birth canal
CONGENITAL/ VERTICAL TRANSMISSION
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may be acquired during pregnancy
Rubella virus and Treponema pallidum
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are examples of bacteria that may be transmitted to the infant during delivery
Streptocccus agalactiae and Neisseria gonorrhoeae
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Serves as a route for many respiratory viruses and bacterial pathogens including:
Streptococcus pyogenes
Neisseria meningitidis
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Infectious secretions may come from coughing, sneezing, kissing and nasal drainage
DROPLET INFECTION
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Respiratory secretions can become dried on clothing, bedding, or floors and converted to dust, which may serve as a route of indirect transmission
DROPLET INFECTION
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Route of infection for many sexually transmitted infections (STIs)
SEXUAL CONTACT
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SEXUAL CONTACT examples
Gonorrhea, Syphilis
Chlamydia, HIV Infection
Herpes, Hepatitis B infection
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Mode of direct contact seen w/ the
spread of common cold due to rhinovirus
transmission of GI infections (poor hand-washing, fecally contaminated hands)
HAND-TO-HAND CONTACT
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INDIRECT TRANSMISSION
Fomites
Ingestion of contaminated food and water
Airborne routes
Animal or arthropod vectors
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Frequent routes of nosocomial infections
fomites
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Inanimate objects such as eating utensils, medical instruments, clothing, money, doorknobs, etc
fomites
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Result of improper or poor sanitary measures
CONTAMINATED FOOD & WATER
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CONTAMINATED FOOD & WATER Associated microorganisms include:
Salmonella
Shigella
Escherichia coli
Hepatitis A virus
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Infections may be incidentally transmitted to humans through infected animals or insect (arthropod vectors)
VECTORS
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Inhalation of infectious particles (aerosols) suspended in air
AIRBORNE
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SIGNS OF INFECTION
Acute infection
Chronic or subacute infection
Local signs of infection
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Chronic or subacute infection
Intermittent, low-grade fever
Weight loss
Fatigue
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Local signs of infection
Pain (dolor)
Heat (calor)
Redness (rubor)
Swelling (tumor)
85
Acute infection
High-grade, spiking fever
Chills
Vasodilation w/ flushing
Increased pulse rate
86
Differential wbc count
Bacterial infections
Viral infections
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Bacterial infections
increased percentage of neutrophils
88
Viral infections
increased percentage of lymphocytes
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OCCURRENCE OF A DISEASE
INCIDENCE
PREVALENCE
90
INCIDENCE
refers only to new cases
91
PREVALENCE
old and new cases of a disease
92
CLASSIFICATION OF DISEASES
COMMUNICABLE DISEASE
CONTAGIOUS DISEASE
NON-COMMUNICABLE DISEASE
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COMMUNICABLE DISEASE
disease that spreads from one host to another either directly or indirectly
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CONTAGIOUS DISEASE
disease thaqt easily spreads from one person to another.
95
SPECIFIC GROUP of signs or symptoms may always accompany a particular disease
SYNDROME
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If disease is not spread from one host to another
NON-COMMUNICABLE DISEASE
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Caused by microorganisms that normally inhabit the body and only occasionally produce disease.
NON-COMMUNICABLE DISEASE
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Caused by microorganisms that reside outside the body and produce a disease only when introduced into the body.
NON-COMMUNICABLE DISEASE
99
HERD IMMUNITY
when many immune people are present in a community that they would act as barriers to the spread of infectious agents
