Microbiology Fundamentals: A Clinical Approach, 2nd ed. by
Cowan Chapter 2
Five I's of Microbiology - (correct Answer) - Inoculation
Incubation
Isolation
Inspection
Identification
Specimen Collection (before the Five I's) - (correct Answer) - Nearly any object/material can serve as a
source of microbes (common ones are body fluid & tissues, foods, water, soil)
Specimens are removed by some form of sampling device (swabs, etc)
Inoculation - (correct Answer) - Implantation of microorganisms into/onto culture media to get it to grow
Clinical specimens include blood, cerebrospinal fluid, sputum, urine, feces, diseased tissue
Media - (correct Answer) - Nutrient used to grow microorganisms outside their natural habitat
Sterile medium containing appropriate nutrients to sustain growth
Solid medium into flask or tube of liquid media
Selection of media with specialized functions can improve later steps of isolation and identification
Some microbes may require a live organism (animal, egg) as the growth medium
Culture media may be contained in test tubes, flasks, petri dishes
Media may be inoculated with loops, needles, pipettes, or swabs
Sterile technique is necessary
Liquid, semisolid, solid/reversible to liquid
Agar - (correct Answer) - Complex polysaccharide from the alga Gellidium
Liquifies at 100 degrees Celsius & solidifies at 42 degrees Celsius, can be poured in liquid form that will
not harm microbe or handle
Flexible & moldable, can hold moisture & nutrients
Not a digestible nutrient for microorganisms because it's able to stay solid at room temp
Made from seaweed
, We add stuff on top of Agar to make things grow
Chemically Definable Media - (correct Answer) - Media whose compositions are precisely chemically
defined
Contain pure organic & inorganic compounds that vary little from one source to another
Molecular content specified by an exact formula
Minimal Media - (correct Answer) - Contain nothing more that a few essential compounds such as salts &
amino acids
Some contain a variety of defined organic & inorganic chemicals
Complex Media - (correct Answer) - Contain at least one ingredient that is NOT chemically definable
(some type of extract from animals, plants, or yeasts)
Blood, serum, meat extracts, or infusions
Present a rich mixture of nutrients for microbes that have complex nutritional needs
Selective Media - (correct Answer) - Contains one or more agents that inhibit the growth of certain
microbes but not others
Important in primary isolation of specific type of microorganism from samples containing dozens of
species
Actively selects different types of bacteria & lets one grow
Differential Media - (correct Answer) - Allow multiple types of microorganisms to grow but are designed
to display differences among those microorganisms
Differentiation shows as variations in colony size or color, media color changes, formation of gas bubbles,
or precipitates
All species grow but show different reactions
Selective & Differential Media - (correct Answer) - Dyes are often used as pH indicators that change
colors in response to the production of an acid or a base
Reducing Media - (correct Answer) - Contains a substance (thioglycolic acid or cystine) that absorbs O2
or slows the penetration of O2
Important in growing anaerobic bacteria/deciding microorganism's O2 needs
Obligate aerobe - (correct Answer) - Needs O2 to live, grows at top of tube where O2 is
Obligate anaerobe - (correct Answer) - Hates O2, grows at bottom of tube/far away from O2
Facultative anaerobe - (correct Answer) - Can utilize O2 but don't need it, grows everywhere in tube but
mostly at top because O2 provides more energy
Cowan Chapter 2
Five I's of Microbiology - (correct Answer) - Inoculation
Incubation
Isolation
Inspection
Identification
Specimen Collection (before the Five I's) - (correct Answer) - Nearly any object/material can serve as a
source of microbes (common ones are body fluid & tissues, foods, water, soil)
Specimens are removed by some form of sampling device (swabs, etc)
Inoculation - (correct Answer) - Implantation of microorganisms into/onto culture media to get it to grow
Clinical specimens include blood, cerebrospinal fluid, sputum, urine, feces, diseased tissue
Media - (correct Answer) - Nutrient used to grow microorganisms outside their natural habitat
Sterile medium containing appropriate nutrients to sustain growth
Solid medium into flask or tube of liquid media
Selection of media with specialized functions can improve later steps of isolation and identification
Some microbes may require a live organism (animal, egg) as the growth medium
Culture media may be contained in test tubes, flasks, petri dishes
Media may be inoculated with loops, needles, pipettes, or swabs
Sterile technique is necessary
Liquid, semisolid, solid/reversible to liquid
Agar - (correct Answer) - Complex polysaccharide from the alga Gellidium
Liquifies at 100 degrees Celsius & solidifies at 42 degrees Celsius, can be poured in liquid form that will
not harm microbe or handle
Flexible & moldable, can hold moisture & nutrients
Not a digestible nutrient for microorganisms because it's able to stay solid at room temp
Made from seaweed
, We add stuff on top of Agar to make things grow
Chemically Definable Media - (correct Answer) - Media whose compositions are precisely chemically
defined
Contain pure organic & inorganic compounds that vary little from one source to another
Molecular content specified by an exact formula
Minimal Media - (correct Answer) - Contain nothing more that a few essential compounds such as salts &
amino acids
Some contain a variety of defined organic & inorganic chemicals
Complex Media - (correct Answer) - Contain at least one ingredient that is NOT chemically definable
(some type of extract from animals, plants, or yeasts)
Blood, serum, meat extracts, or infusions
Present a rich mixture of nutrients for microbes that have complex nutritional needs
Selective Media - (correct Answer) - Contains one or more agents that inhibit the growth of certain
microbes but not others
Important in primary isolation of specific type of microorganism from samples containing dozens of
species
Actively selects different types of bacteria & lets one grow
Differential Media - (correct Answer) - Allow multiple types of microorganisms to grow but are designed
to display differences among those microorganisms
Differentiation shows as variations in colony size or color, media color changes, formation of gas bubbles,
or precipitates
All species grow but show different reactions
Selective & Differential Media - (correct Answer) - Dyes are often used as pH indicators that change
colors in response to the production of an acid or a base
Reducing Media - (correct Answer) - Contains a substance (thioglycolic acid or cystine) that absorbs O2
or slows the penetration of O2
Important in growing anaerobic bacteria/deciding microorganism's O2 needs
Obligate aerobe - (correct Answer) - Needs O2 to live, grows at top of tube where O2 is
Obligate anaerobe - (correct Answer) - Hates O2, grows at bottom of tube/far away from O2
Facultative anaerobe - (correct Answer) - Can utilize O2 but don't need it, grows everywhere in tube but
mostly at top because O2 provides more energy
