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Microbiology 1
test 1
49
Microbiology
Undergraduate 1
01/26/2014

Additional Microbiology Flashcards

 


 

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Term
Bio safety Level 1
Definition
Agents have no known potential for infecting healthy people
Term
Bio safety Level 2
Definition
i. Most clinical labs fall into this category
ii. Agents handled include all the common agents of infectious disease as well as HIV
iii. Requires limited access and training of laboratory personnel
iv. Hep B vaccine must be offered to all employees
Term
bio safety Level 3
Definition
i. Agents handled are unlikely to be handled in the routine clinical lab
ii. Mycobacteria, mold stages of systemic fungi and other highly infectious agents
iii. Special room and ventilation required as well as special protective clothing
Term
bio safety Level 3
Definition
i. Level 3 plus entrance through a separate room. Street clothing changed and replaced with laboratory clothing. All personnel and materials are decontaminated before leaving the area
ii. Primarily research and public health facilities such as the CDC
Term
Biosafety Cabinets Class I
Definition
allows room air to flow into the cabinet and around the area and material within
Term
Biosafety Cabinets Class 2
Definition
Sterilize both the air that flows over the infectious material and the air that is exhausted.
Generally used in most hospital laboratories.
Term
Biosafety Cabinets Class 3
Definition
Level II plus it is a closed system where rubber gloves are used in handling samples. There is no
direct contact from outside the system. Generally used in Biosafety level 4 labs
Term
Nomenclature 1
Definition
The naming of microorganisms according to established rules and guidelines provides the accepted labels by which organisms are universally recognized. The genus and species of an organism are of most concern to microbiologists.
Term
Nomenclature 2
Definition
i) By convention the genus is always Capitalized and the species is not
ii) Both are either underlined or italicized
Term
Identification Genotype
Definition
relates to an organisms genetic makeup such as DNA or RNA
Term
Identification Phenotype
Definition
Macroscopic morphology – Growth patterns on artificial media
ii) Microscopic morphology – Size, shape, appendages etc.
iii) Staining characteristics – Ability of organism to stain a particular color
iv) Environmental requirements – Temperature requirements
v) Nutritional requirements – Carbon and nitrogen utilization patterns, carbohydrate fermentation
vi) Antigenic properties – profiles by serologic methods
vii) Subcellular properties – Cell wall and membrane components
Term
Coccus
Definition
i. Plural – Cocci meaning berries
ii. Diplococci – pairs
iii. Streptococci – chains
iv. Tetrads – groups of 4
Term
Bacillus
Definition
i. Plural – bacilli meaning little staffs
ii. Diplobacilli – pairs
iii. Streptobacilli – chains
iv. Coccobacilli – Bacilli that are oval and may appear more like Cocci
Term
Spiral
Definition
i. Vibrios – Bacteria that look like curved rods
ii. Spirilla – helical or corkscrew shape and are rigid
iii. Spirochetes – Helical or corkscrew shape and are flexible
Term
Gram positive Cocci
Definition
o Staphylococcus
o Streptococcus
o Enterococcus
Term
Gram Negative Cocci
Definition
o Moraxella catarrhalis – diplococci
o Neisseria gonorrhoeae – diplococci
o Neisseria meningiditis - diplococci
Term
Gram negative Bacilli
Definition
o Bacteroides
o Camplyobacter
o Escherichia coli
o Klebsiella
o Salmonella
o Shigella
Term
Gram positive Bacilli
Definition
o Actinomyces- branched
o Bacillus- long wide, B. anthracis- “safety pins”
o Clostridium
o Corynebacterium ( diphtheroids)- palisades or Chinese letters o Listeria
Term
Gram Variable
Definition
o Gardnerella vaginalis - coccobacilli
Term
Cellular appendages-Capsule
Definition
Exterior to the outer membrane. Referred to as the slime layer, or glycocalyx, is composed of
high molecular weight polysaccharides. Protects bacteria from phagocytic attack by cells of the immune
system and increases adherence of colonization surfaces
Term
Cellular appendages-Fimbriae or pili
Definition
long hair like structures that extend from the cell membrane. Help attach to host cell
surfaces
Term
Cellular appendages-Flagella
Definition
complex structures embedded in cell envelope. Responsible for cell motility if present
Term
Endospores
Definition
Under adverse conditions some bacteria are able to form spores. Involves from an active cell to a dormant cell with a decrease in cytoplasm and an increase in the thickness of the cell envelope. Frequently found in microbes living in soil such as B. anthracis
Term
Normal Flora
Definition
Microorganisms that are commonly found on or in body sites of healthy persons
a. Different body sites have different or the same flora depending on the local conditions
Term
Resident microbial flora
Definition
colonize an area for months or years
Term
Transient microbial flora
Definition
temporarily present at a site, does not normally occur or stay at a particular site. Usually eliminated by immune response or competition w other normal flora
Term
Carrier
Definition
Host person who has established pathogenic flora with no disease present, they are however capable of transmitting disease
Term
Carrier State
Definition
The condition of being a carrier for a pathogenic organism
a. May be Acute, short lived or transient
b. May be Chronic, lasting months, years or permanently
Term
Factors that Affect Normal Flora-Environmental Factors
Definition
a. Factors such as temperature, moisture.
b. pH of the site has a great effect on colonization, as in the female genital tract where the normal pH in women of child bearing age is a very acidic 4.0-5.0. Most bacteria cannot survive in an environment with such a low pH.
Term
Factors that Affect Normal Flora-Nutritional Factors
Definition
a. Presence of chemicals unique to certain body sites and uniquely used by certain species of organisms. presence of chemicals such as lipids (fats), bile, lysozymes, and fatty acids all affect the composition of organisms colonizing each area individually. Ex. Propionibacterium acnes colonize the ducts of hair follicles because it is able to break down the skin lipids into fatty acids
Term
Sterile Body Sites- Lower Respiratory Tract(were specimen and testing for)
Definition
Trachea, bronchi and lungs a. Specimen- Sputum, bronchial lavage
b. Pathogens
I. Streptococcus pneumonia
ii. H. influenzae
Term
Sterile Body Sites-Upper Genitourinary Tract-(were specimen and testing for)
Definition
a. Specimen – Cath Urine, Surgical specimens
b. Pathogens- generally coliform bacteria cause infections of the urinary tract
i. E. coli
ii. Proteus mirabilis
iii. Staph saprophyticus
Term
Sterile Body Sites-CNS-(were specimen and testing for)
Definition
Brain, spinal cord and Cerebral Spinal fluid a. Specimen – CSF cerebral spinal fluid
b. Pathogens
i. E. coli
ii. Neisseria meningitis
Term
Sterile Body Sites-Peritoneal Cavity(were specimen and testing for)
Definition
(abdominal cavity) a. Specimen – Ascites fluid
b. Pathogens – Coliform bacteria from GI tract
Term
Sterile Body Sites-Synovial capsules(were specimen and testing for)
Definition
( fluid filled joints) a.Specimen – synovial fluid
b. Pathogens
i. N. gonorrhoeae
ii. Staphylococcus aureus
Term
Sterile Body Sites-Blood(were specimen and testing for)
Definition
a. Specimen – blood cultures are collected directly from the blood stream into enriched broth for incubation b. Pathogens – Many
i. E. Coli, Staph aureus
ii. Almost any infection site can become systemic when the bacteria from an infection site enter the blood stream and multiply
iii. Condition known as Sepsis or Septicemia indicated by abrupt onset of fever and chills
iv. Can be Aerobic or Anaerobic bacteria
Term
Laboratory diagnosis of infectious diseases involves
Definition
 Direct examination of patient specimens for presence of etiologic agents ( bacteria, fungi) and for
sample integrity.
o Direct exam of a wet prep mount of vaginal secretions for report of white blood cells,
trichomonas, yeast cells and clue cells
o KOH prep – used to dissolve skins cells and detect the presence of fungal elements
 Isolation, growth and cultivation of the microbes
 Analysis of the cultivated organisms to establish identification
Term
Simple Stains
Definition
Methylene blue – imparts the same color to all parts
Term
Differential Stains
Definition
Gram Stain
o Acid-fast Stain – Used to Stain Mycobacteria o Capsular Stain –
o Endospore Stain
o Flagella Stain
Term
Gram Stain
Definition
 Primary Stain – crystal violet
 Mordant – iodine
 Decolorizer- alcohol or acetone  Secondary Stain – Safrinin
Gram positive organisms retain the purple crystal violet coloration
Gram negative organisms release the crystal violet/iodine complex and stain pink with the Safrinin White blood cells appear pink to reddish orange in a gram stained specimen as opposed to the purple color seen in a Wright Stained blood smear
Term
Negative Stain
Definition
India Ink – dark background for use in visualizing the capsule surrounding certain organisms such as the
yeast Cryptococcus which has a large capsule
Term
Specimen Collection and Handling-Wounds
Definition
a) Swabs are easily contaminated and dry out quickly
b) If used, usually are placed in transport gel to retain specimen integrity
c) Deep wound or abscess specimens are best collected by needle aspiration, NOT SWABS
d) Note the type of sample and the anatomical site of collection
Term
Specimen Collection and Handling-Urine
Definition
clean-catch or nurse collected catheter specimen
Term
Specimen Collection and Handling-Sputum
Definition
a) Sputum samples may be refrigerated for transport in a sterile container
b) Sputum vs. Saliva
i) Sputum samples are gram stained upon receipt in the lab to determine specimen integrity. Specimens with >24 epithelial cells and multiple organisms are generally rejected due to contamination with oral flora.
Term
Specimen Collection and Handling-Spinal Fluid
Definition
suspected meningitis
a) Should be handled stat and processed immediately.
b) Gram stain always performed, normal specimen is sterile, no organisms seen
c) Cultures are performed with specimen inoculated to chocolate agar and thio broth to enhance chances of
recovering fastidious organisms
d) May be held at 370c up to 6 hours prior to culture if needed
Term
Specimen Collection and Handling-Fecal Specimens
Definition
a) Collected to diagnose GI pathogens such as Salmonella and Shigella, common food poisoning assoc. organisms
b) Preserve at 7.0pH if testing is to be delayed
c) Special preservative vials are used for O&P samples to preserve those organisms
Term
Specimen Collection and Handling-Blood Cultures
Definition
collected directly into broth bottles
a) Used to diagnose Bacteremia or Septicemia
b) Sterile technique is imperative in collection of samples
c) Normally collected at least two times form two different sites
d) Avoid refrigeration
Term
Specimen Collection and Handling-Throat
Definition
a) Usually 2 swabs are collected, one may be used for rapid testing of Group A Beta Strep (S. pyogenes)
b) The Second swab is used for culture
c) Transport within one hour
Term
Specimen Collection and Handling-Anaerobic organisms
Definition
Some are very sensitive to environmental changes and will not be recovered on culture if not handled properly.
a) Obligate Anaerobes – cannot live in the presence of oxygen.
i) Specimens for anaerobes must be places immediately into anaerobic transport gel to preserve those
organisms
b) Facultative Anaerobes – many organisms isolated from the GI tract are facultative anaerobes. They can grow
with or without the presence of oxygen.
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