Lecture 12: Normal Microbiota and the Host

Question 1

Normal Microbiota _____ colonize the host

Answer 1

permanently

Question 2

Transient microbiota may present in host for

Answer 2

days, weeks, or months

Question 3

The relationship between nomral microbiota and the host

Answer 3

symbiosis

Question 4

An association of two or more different species of organisms

Answer 4

symbiosis

Question 5

Physical contact between dissimilar organisms

Answer 5

Symbiont

Question 6

What is commensalism

Answer 6

An association between two organisms in which one benefits and the other is unaffected

Question 7

What is mutualism

Answer 7

both organisms benefit

Question 8

What is parasitism

Answer 8

One organism benefits at the expense of the other

Question 9

Microbial antagonism is a ____ between microbes

Answer 9

competition

Question 10

Normal microbiota protect the host by:

Answer 10

• Occupying niches that pathogens might occupy
• Producing acids
• Producing bacteriocins

Question 11

What is a Microbiome

Answer 11

• All the genes of the host and the microbiota

Question 12

Superorganisms

Answer 12

• Emerge when the gene-encoded metabolic processes of the host become integrated with those of the microbe
• a blend of host and microbial traits where host and microbial cells cometabolize various substrates, resulting in unique products

Question 13

Germfree animals can be used

Answer 13

• can be used to study effects of microbes on animal health by
  
  • comparing gerfree animals to normal animals
  • introducing a single microbe to the germfree animal and observing effects
• Can be coupled with genomic studies for maximum benefits

Question 14

What are Germfree animals produced

Answer 14

• Cesarean section, raised in sterility

Question 15

What is the Human Microbiome Project

Answer 15

• Attempt to define ‘normal’ populations of microbes in and on human beings

Question 16

as of 2012 the human microbiome project had genome reference collection for ___ microorganisms (out of an anticipated 900) obtained

Answer 16

178

Question 17

What are the reasons to study Normal Human Microbiota

Answer 17

• To gain insight into possible infections resulting from injury
• To understand causes and consequences of overgrowth of microbes normally absent from a body site
• To increase awareness of role played by indigenous microbe in stimulating immune responses

Question 18

Bifidobacteria is found in

Answer 18

• breast fed babies

Question 19

What is Protrophic

Answer 19

• can synthesize all amino acids and growth factors from simple carbohydrates

Question 20

Normal microbiota protect the host by

Answer 20

• competing with pathogens or altering the environment
  
  • occupying niches that pathogens might occupy
  • Producing acids
  • Producing bacteriocins

Question 21

Probiotics

Answer 21

• Live microbes applied to or ingested into the body, intended to exert a beneficial effect

Question 22

Members of normal microbiota that produce disease under certain circumstances

Answer 22

Opportunistic pathogens

Question 23

Debiliated host with lowered resistance to infection

Answer 23

Compromised host

Question 24

Normal Microbiota of the skin

Answer 24

• Mechanically strong barrier
• Inhospitable environment
  
  • slightly acidic pH
  • high concentration of NaCl
  • many areas low in moisture
• Inhibitory substances (e.g., lysozyme)
• mostly Gram-positive, salt tolerant bacteria
  
  • Staphylococci (ex. S. epidermis)
  • Micrococci (ex. M. luteus)
  • Diphtheroids
    
    • Aerobes on surface
      
      • Corynebacterium xerosis
    • Anaerobes in hair follicles
      
      • Propionibacterium acnes
• a few gram-negative organisms (ex. Acinetobacter)
• grow on oils
  
  • yeast
    
    • ex. Malassezia furfur

Question 25

Anaerobes in hair follicles

Answer 25

Propionibacterium acnes

Question 26

is the bacteria on the skin gram positive or gram negative

Answer 26

mostly gram positive with a few gram-negative organisms (ex. Acinetobacter)

Question 27

Acne Vulgaris

Answer 27

* Caused in part by activities of Propionibacterium acnes * Sebum * fluid secreted by oil glands * accumulates, providing hospitable environment for P. acnes * Comedo * plug of sebum and keratin in duct of oil gland * results from inflammatory response to sebum accumulation

Question 29

Normal Microbiota of the eye

Answer 29

* From birth throughout a human life, small numbers of bacterial commensals are found on the conjunctiva of the eye * The predominant bacterium is Staphylococcus epidermis

Question 30

Normal microbiota of the external ear

Answer 30

similar to skin flora as well as fungi

Question 31

Normal Microbiota are responsible for dental caries examples:

Answer 31

* S. mutans * Lactobacillus

Question 32

Normal Microbiota of the Mouth

Answer 32

* Contains organisms that survive mechanical removal by adhering to gums and teeth * Contribute to formation of dental plaque, dental caries, gingivitis, and periodontal disease * Within hours of birth, the oral cavity is colonized by microorganisms from the surrounding environment * Oral bacteria are responsible for dental caries (ex. S. mutans and Lactobacillus) * Suppress pathogens by competitive inhibition in upper respiratory system

Question 33

What two bacteria are found inside the nostrils

Answer 33

* Staphylococcus aureus * S. epidermis

Question 34

The Pharynx and trachea contina Gram\_\_\_\_ bacteria:

Answer 34

* gram positive bacteria * Staphylococci (ex. S. epidermis) * Micrococci (ex. M. luteus) * Diphtheroids * Streptococci (both alpha and beta-hemolytic

Question 35

Nasopharynx may contian low numbers of potentially pathogenic microbes such as

Answer 35

* Streptococcus pneumoniae * Neisseria meningitidis * haemophilus influenza * Mycoplasmas

Question 36

Does the lower respiratory tract have a normal microbiota

Answer 36

* No * Microbes moved by: * Continuous stream of mucous generated by ciliated epithelial cells * cilliary escalator * Phagocytic action of alveolar macrophages * lysozyme in mucus

Question 37

Most microbes of the stomach are

Answer 37

* killed by acidic conditions * some survive if pass through stomach very quickly * Some can survive if ingested in food particles

Question 38

Which part of the small intestine has the most microbes

Answer 38

* The ileum * flora present becoming similar to that in colon * pH becomes more alkaline

Question 39

What has the largest microbial population in the body

Answer 39

The large intestine (colon)

Question 40

The microbial population of the large intestine (Colon) is eliminated from body by _____ but replaced rapidly by

Answer 40

* peristalsis, desquamation, and movement of mucus * High reproductive rate

Question 41

most of the microbes in the large intestine (colon) are

Answer 41

anaerobes

Question 42

Microbes in the large intestine (colon)

Answer 42

* E.coli * Bacteroides * Fusobacterium * Lactobacillus * Enterococcus * Bifidobacterium * Enterobacter * Citrobacter * Proteus * Klebsiella * Candida (fungus)

Question 43

What parts of the genitourinary tract is normally free of microbes

Answer 43

Kidneys, ureter, and bladder

Question 44

Why is the female genital tract's microbiota in a complex state of flux due to ______ with ______ predominating

Answer 44

* menstrual cycle * Acid-tolerant lactobacilli

Question 45

\_\_\_\_\_\_\_ microbiota are predominant in the vagina

Answer 45

* Lactobacilli * produce H₂O₂ * _​Grow on glycogen secretions

Question 46

Urinary infection is indicated by

Answer 46

* \> 10,000 bacteria/mL * 100 coliforms/mL * Positive urine leukocyte esterase (LE) test

Question 47

The "extinction" of H. pylori is linked to several immune and metabolic disorders such as

Answer 47

Asthma, allergies, celiac disease, even acid reflux disease