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Practice topics Exam 1 > Bacteria 2 > Flashcards

Bacteria 2 Flashcards

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1
Q

Biofilms - most bacteria live how

A

NOT planktnically - they are not freely moving

Most are sessile and adherent to a surface or to other bacteria as part of a biofilm

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2
Q

Biofilms are what

A

bacteria encased in a exopolymeric substance (polysaccharide, DNA, protein…) of their own making

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3
Q

Biofilms are found where

A

throughout nature on surfaces that are commonly moist/wet

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4
Q

Biofilms - cells

A

cells in a biofilm are different than planktonic cells

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5
Q

Biofilms - cells - how are they different

A

Altered metabolism, generally slower
Increased resistance to antibiotics
Increased genetic exchange (inc likelihood of antibiotic resistance transfer)
Resistant to disinfection - increased organic matter and decreased diffusion

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6
Q

Host-Microbe Interactions - Medical microbiology

A

Study of dynamic interaction between microbes and the human host

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7
Q

Host-Microbe Interactions - Symbiosis

A

Close and prolonged association between 2 or more organisms of different species

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8
Q

Host-Microbe Interactions - Commensalism

A

Shelter and food
Ex - Bacteroides spp - human large intestine
Host provides environment and nutrition
Bacteria ferment digested food
Large bacterial population
Harmful if tissue damaged, gut flora changes or immunity reduced

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9
Q

Host-Microbe Interactions - Mutualism

A 
Reciprocal benefit
Bacteroids spp - cattle rumen
Host provides environment and nutrition
Bacteria metabolize food into fatty acids/gasses
Host uses fatty acids as energy source
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10
Q

Host-Microbe Interactions - Parasitism

A

Unilateral benefit
Helicobacter pylori - human stomach
Host provides environment
Local invasion of the stomach epithelium by bacteria leading to ulcers, stomach bleeding, potentially cancer

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11
Q

Niche - types

A

shelter (physical space in/on the body)

food (nutrients)

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12
Q

Niches and normal bacteria - normal micobiota (flora)

A

Often commensal or mutual symbionts adapted to specific niches
Tend to avoid directly injuring the host
Can be beneficial to the host - compete with pathogens for niche (competitive exclusion), can produce toxins that harm pathogenic microorganisms

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13
Q

Normal microbiota - fetus vs. neonate

A

Fetus - sterile
Neonate - if vaginal delivery is colonized with birth, if C section is rapidly colonized after birth with skin/skin contact

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14
Q

Normal microbiota - colonized sites

A

Skin
Mucosa
Intestine
Urogenital tract

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15
Q

Normal microbiota - normally sterile

A

Internal organs and tissue
Cervix
Middle ear
Urinary bladder

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16
Q

Normal microbiota - childhood vs. normal healthy adult vs. elderly

A

Child - developing immunity, exposure to new microbes
Healthy adult - developed immunity
Elderly - immune senescence, inc risk of infection

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17
Q

Resident vs. Transient Microbiota

A 
Resident = long term members of the bodys normal microbiota
Transient = organisms that attempt to colonize to body but are unable to remain
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18
Q

Transient microbiota - are unable to remain due to

A

Competition from resident microbiota
Elimination by body immune system
Physical or chemical changes within the body that discourage growth

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19
Q

Resident (normal) microbiota - Skin

A

Staphylococcus epidermidis - skin, nose, external ear canal
Gram pos cocci, in clusters
Infections associated with prosthetic devices and IV catheters
Common contaminant of blood cultues!!!

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20
Q

Transient microbiota - ex

A

Group A strep (GAS) - streptococcus pyogenes
Gram pos cocci, in chains
Transiently colonize oropharynx of children and young adults in absence of clinical disease
Causative agent of strep throat

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21
Q

Pathogens = what

A

any microorganism that has the capability to cause disease

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22
Q

Strict pathogens

A

Organisms always associated with disease
If in a person, it will cause disease
Ex - TB, gonorrhea, rabies

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23
Q

Opportunistic pathogens

A

tend to be members of the normal microbiota

take advantage of preexisting conditions such as immunosuppression to cause disease

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24
Q

Are most infectious disease of humans caused by strict pathogens or opportunistic?

A

OPPORTUNISTIC!

We are exposed to them all the time!

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25
Ex of opportunistic infections
``` Contamination of IV cath Wound/surgical site infection Bacterial endocarditis Aspiration pneumonia UTI Pseudomembrane colitis Otitis media ```
26
Carrier state - carrier =
An asymptomatic individual who is host to a pathogen Has the potential to transmit the pathogen to others Condition of being a carrier may be transient or (semi) permanent depending on what one is carrying and how it can be cleared/removed
27
Pathogenicity and Virulence
Often used interchangeable Pathogenicity = ability of a microorganism to cause disease Virulence = a measurement of pathogenicity (how severe the disease might be)
28
Virulence factors
Factors (toxins) produced by organisms that enable it to infect, cause disease, and/or kill a host
29
Events associated with infection
entry into the host adhesion and colonization pathogenic action of bacteria mechanisms for escaping hose defenses
30
Entry into the host (and shedding)
``` Transplacental (mother to fetus) Secretions Stool (fecal to oral) Skin (cuts) Blood Zoonotic (animal to human) Arthropod ```
31
Entry into host - barriers
``` Mechanical (skin, cilia) Enzymatic (lysozyme) Chemical (acidic pH) Immunity Commensals (niche environment) Physical (sheer forces, peristalsis) ```
32
Sterilization
Destroy all microbial forms including bacterial spores
33
Disinfection
Destroy most microbial forms Bacterial spores and other resistant organisms (viruses, fungi) might remain viable Subdivided into high, intermediate and low level agents
34
Antisepsis
Disinfectants used on skin or other living tissue to inhibit or eliminate microbes; no sporicidal action is implied
35
Pasteurization
Heating milk or other liquids to destroy microorganisms
36
Sterilization destruction of what
complete destruction or elimination of viable organisms | Nonselective and harsh! Inactivates mycobacteria sports, and prions
37
Sterilization - common methods
Heat - moist or dry Radiation Chemicals Filtration
38
Sterilization - moist heat
Autoclaving (pressure cooker) MOA - denatures proteins, causes single strand breaks in DNA, compromises membrane integrity Kill spores Is nontoxic Used for items not damaged by hear, moisture, pressure
39
Sterilization - boiling
Boiling is NOT sterilization!!! It is a method of disinfection!
40
Sterilization - dry heat
MOA - protein denaturation, single stranded DNA breaks, compromises membrane integrity Kills spores, non toxic Used for metals, glass
41
Sterilization - ethylene oxide gas
Colorless, flammable gas MOA - alkylates proteins, DNA and RNA Kills spores, toxic/mutagenic - must dissipate gas Used for moisture/heat sensitive items
42
Sterilization - radiation - UV light
Direct exposure required (only non-porous surface) | MOA - DNA damage
43
Sterilization - radiation - Ionizing radiation - irradiation
Exposure to radiation source | MOA - DNA damage, generation of oxidizing agents
44
Sterilization - filtration
Useful for removing bacteria and fungi from air, liquid | MOA - physical removal of bacteria
45
Disinfection
Killing most, but not all, viable organisms from surfaces
46
Disinfection - high class
Kills all microbial pathogens except large numbers of spores | Surfaces that cannot be sterilized (endoscope)
47
Disinfection - high class ex
Glutaridehyde Concentrated hydrogen peroxide Peracetic acid Chlorine compounds (bleach)
48
Disinfection - intermediate class
Kills all mircrobial pathogens except spores | Surfaces unlikely to be contaminated with spores (laryngoscopes)
49
Disinfection - intermediate class - ex
Alcohols Iodophors Phenosis
50
Disinfection - low class
kills most bacteria and lipid enveloped viruses | Surface of non critical instruments - stethoscope
51
Disinfection - low ex
Quaternary ammonium compounds
52
Effectiveness of disinfectants - depends on
``` Surface/item to be disinfected Level of contamination Type of contamination Amount of organic matter present Concentration of disinfectant Duration and temperature of exposure ```
53
Antiseptics
``` Distinct subclass of disinfectants Does NOT kill bacterial spores ```
54
Reason for use - antiseptics
Reduce the number of microorganisms on the skin surface
55
Antiseptics - ex
``` Alcohols Phenolics Iodine Chlorhexidine Quaternary ammonium compounds Triclosan ```
56
Antiseptics - alcohol
Ethanol and Isopropanol - commonly used before venipuncture MOA - denature proteins, cell membrane damage Activity greater in presence of water (to a point) Optimal range is 60-90% (hand sanitizer is in this range)
57
Antiseptics - Iodine
Most effective antiseptic | Recommended to be applied prior to vnipuncture or installation of IV cath
58
Antiseptic - Iodine - Iodophors
Iodine complexed with a solubilizing agent (povidone) | Considered the most stable/universally perferred iodine antiseptic
59
Antiseptic - Iodine - MOA
Quick penetration of cells, disruption of membrane and essential cell process
60
Antiseptic - Chlorhexadine
Broad antimicrobial activity - slow acting, residual activity MOA - disrupts cell membranes Newer solutions contain - alcohol, detergent Some hospitals are using this over iodine for catheter installation
61
Antiseptic - Chlorhexadine - alcohol and detergent
Alcohol - inc effectiveness | Detergent - very effective for decontaminating skin, used commonly for surgical scrub in
62
Standard procedures
Assume every person is potentially infected or colonized Hand hygiene before and after EVERY patient Use protection when exposure to secretions is possible Follow sharps guidelines
63
Hand hygiene
Avoid unnecessary contact with surfaces to avoid contamination Visible hand contamination - wash with soap and water Not visible - alcohol based hand sanitizer Change gloves often if prolonged time with single pt Do not wear artificial fingernails or have long nails
64
Washing hands vs. Alcohol based sanitizer
Washing hands will remove spores | Sanitizer will not kill spores

Practice topics Exam 1 (15 decks)

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