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Practice topics Exam 1 > Bacteria 2 > Flashcards

Bacteria 2 Flashcards

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
Q

Ex of opportunistic infections

A 
Contamination of IV cath
Wound/surgical site infection
Bacterial endocarditis
Aspiration pneumonia
UTI
Pseudomembrane colitis
Otitis media
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26
Q

Carrier state - carrier =

A

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
Q

Pathogenicity and Virulence

A

Often used interchangeable
Pathogenicity = ability of a microorganism to cause disease
Virulence = a measurement of pathogenicity (how severe the disease might be)

28
Q

Virulence factors

A

Factors (toxins) produced by organisms that enable it to infect, cause disease, and/or kill a host

29
Q

Events associated with infection

A

entry into the host
adhesion and colonization
pathogenic action of bacteria
mechanisms for escaping hose defenses

30
Q

Entry into the host (and shedding)

A 
Transplacental (mother to fetus)
Secretions
Stool (fecal to oral)
Skin (cuts)
Blood 
Zoonotic (animal to human) 
Arthropod
31
Q

Entry into host - barriers

A 
Mechanical (skin, cilia)
Enzymatic (lysozyme)
Chemical (acidic pH)
Immunity
Commensals (niche environment)
Physical (sheer forces, peristalsis)
32
Q

Sterilization

A

Destroy all microbial forms including bacterial spores

33
Q

Disinfection

A

Destroy most microbial forms
Bacterial spores and other resistant organisms (viruses, fungi) might remain viable
Subdivided into high, intermediate and low level agents

34
Q

Antisepsis

A

Disinfectants used on skin or other living tissue to inhibit or eliminate microbes; no sporicidal action is implied

35
Q

Pasteurization

A

Heating milk or other liquids to destroy microorganisms

36
Q

Sterilization destruction of what

A

complete destruction or elimination of viable organisms

Nonselective and harsh! Inactivates mycobacteria sports, and prions

37
Q

Sterilization - common methods

A

Heat - moist or dry
Radiation
Chemicals
Filtration

38
Q

Sterilization - moist heat

A

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
Q

Sterilization - boiling

A

Boiling is NOT sterilization!!! It is a method of disinfection!

40
Q

Sterilization - dry heat

A

MOA - protein denaturation, single stranded DNA breaks, compromises membrane integrity
Kills spores, non toxic
Used for metals, glass

41
Q

Sterilization - ethylene oxide gas

A

Colorless, flammable gas
MOA - alkylates proteins, DNA and RNA
Kills spores, toxic/mutagenic - must dissipate gas
Used for moisture/heat sensitive items

42
Q

Sterilization - radiation - UV light

A

Direct exposure required (only non-porous surface)

MOA - DNA damage

43
Q

Sterilization - radiation - Ionizing radiation - irradiation

A

Exposure to radiation source

MOA - DNA damage, generation of oxidizing agents

44
Q

Sterilization - filtration

A

Useful for removing bacteria and fungi from air, liquid

MOA - physical removal of bacteria

45
Q

Disinfection

A

Killing most, but not all, viable organisms from surfaces

46
Q

Disinfection - high class

A

Kills all microbial pathogens except large numbers of spores

Surfaces that cannot be sterilized (endoscope)

47
Q

Disinfection - high class ex

A

Glutaridehyde
Concentrated hydrogen peroxide
Peracetic acid
Chlorine compounds (bleach)

48
Q

Disinfection - intermediate class

A

Kills all mircrobial pathogens except spores

Surfaces unlikely to be contaminated with spores (laryngoscopes)

49
Q

Disinfection - intermediate class - ex

A

Alcohols
Iodophors
Phenosis

50
Q

Disinfection - low class

A

kills most bacteria and lipid enveloped viruses

Surface of non critical instruments - stethoscope

51
Q

Disinfection - low ex

A

Quaternary ammonium compounds

52
Q

Effectiveness of disinfectants - depends on

A 
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
Q

Antiseptics

A 
Distinct subclass of disinfectants 
Does NOT kill bacterial spores
54
Q

Reason for use - antiseptics

A

Reduce the number of microorganisms on the skin surface

55
Q

Antiseptics - ex

A 
Alcohols
Phenolics
Iodine
Chlorhexidine
Quaternary ammonium compounds
Triclosan
56
Q

Antiseptics - alcohol

A

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
Q

Antiseptics - Iodine

A

Most effective antiseptic

Recommended to be applied prior to vnipuncture or installation of IV cath

58
Q

Antiseptic - Iodine - Iodophors

A

Iodine complexed with a solubilizing agent (povidone)

Considered the most stable/universally perferred iodine antiseptic

59
Q

Antiseptic - Iodine - MOA

A

Quick penetration of cells, disruption of membrane and essential cell process

60
Q

Antiseptic - Chlorhexadine

A

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
Q

Antiseptic - Chlorhexadine - alcohol and detergent

A

Alcohol - inc effectiveness

Detergent - very effective for decontaminating skin, used commonly for surgical scrub in

62
Q

Standard procedures

A

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
Q

Hand hygiene

A

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
Q

Washing hands vs. Alcohol based sanitizer

A

Washing hands will remove spores

Sanitizer will not kill spores

Practice topics Exam 1 (15 decks)

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