Transcript Unit 5E Clin Micro PowerPoint

Unit #5E – Clinical
Laboratory Testing –
Basic Clinical
Microbiology
Includes study of bacteria (bacteriology),
parasites (parasitology), viruses (virology)
and fungi (mycology)
Cecile Sanders, M.Ed., MLS(ASCP)
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
– Bacteriology
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Study of a large diverse group of single celled
prokaryote microorganisms which multiply by
fission to form a “colony” (on solid media),
which can be observed for characteristic
appearance.
Bacteria cannot be seen with the naked eye.
They can only be seen after staining them with
special dyes and observing them under a
microscope.
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
– Bacterial Microscopic Morphology
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Coccus - round (cocci = plural)
– Example: Streps, staphs, Neisseria
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Diplococcus - cocci in pairs (diplococci = plural)
– Example: Strep. pneumoniae
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Bacillus or rods - parallel sides (bacilli = plural)
– Example: E. coli
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Spirochetes - curved or spiral organisms
– Example: Treponema pallidum
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
– Cocci/Diplococci
– Bacilli/Rods
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
– Spirochetes
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
– Gram Stain
http://www.uphs.upenn.edu/bugdrug/antibiotic_manual/Gram3.htm
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Most bacteria fall into one of two categories:
– Gram-positive = microorganisms that stain purple Example: Streps, staphs
– Gram-negative = microorganisms that stain pink or red
- Example: E. coli, Neisseria
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Purpose of Gram Stain: Provides valuable
information for physician to start antibiotic
therapy, as antibiotics act differently on gram
(+) vs. gram (-) organisms
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
– Gram Positive Cocci
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
– Gram Positive Bacilli
– Gram Negative Cocci
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
– Gram Negative Bacilli
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
–
Clinical Bacteriology Terms
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Pathogens / pathogenic – capable of causing
disease
Communicable - capable of being transferred from
one person to another
Normal flora - natural micro-inhabitants of the
body
Opportunists / Opportunistic pathogens –
organisms that only cause disease in compromised
individuals
Antibiotic susceptibility testing – tests for
sensitivity of organism against various antibiotics
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Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
Specimen collection - Body sites /
fluids cultured to grow microorganisms
– Fastidious organisms - require special
medium / conditions to grow
– Aerobic - organisms which require oxygen
to grow or live
– Anaerobic - organisms which live and grow
only in absence of oxygen.
http://www.shellab.com/bactron.html
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
–
Microbiological Safety Cabinets - H(igh)
E(fficiency) P(article) A(ir filter) “HEPA”
Air moves away from worker, over specimen,
through filter, and vented to outside
http://www.terrauniversal.com/laminarflow-hoods/laboratory-hoods-x.php
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
– Disinfectants - chemicals used on working
areas to kill or control growth of
organisms in their active or vegetative
stages (NOT resting stages, such as
spores). Some harsh disinfectants will kill
spores, too
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EXAMPLE: 10% bleach, phenols
– Antiseptics - chemicals used to control
microorganisms on living tissue
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EXAMPLE: 70% isoprophyl alcohol, Betadine
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
– Sterilization - methods used to kill all
organisms and their resting stages
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EXAMPLE: Autoclaving
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Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
Processing of Specimens
– Agars - solid medium made of seaweed
extract; bacteria grow on these agars and
appear as small to large dots
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Enrichment agars for growth – contain extra
nutrients
– Example: Blood Agar
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
 Differential
agars – differentiate organisms by
color or growth pattern
– Example: MacConkey Agar – inhibits the growth of
gram positive organisms while allowing gram
negative organisms to grow
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
Selective agars –
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Inhibit the growth of
certain
microorganisms while
allowing other
organisms to grow
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Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
Antibiotic Sensitivity (Susceptibility)
Testing
– Kirby-Bauer Method
– MIC – Minimum Inhibitory Concentration –
Provides information on weakest dose of
antibiotic that would be effective
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Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
Parasitology –
– Common human parasites
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Enterobius vermicularis “Pin Worm”
Giardia lamblia
Trichomonas vaginalis
– O & P (Ova and Parasites) - Detection of
Intestinal Parasites
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Helminths - flatworms, round worms, flukes,
or hookworms
Amoeba in cyst or trophozoite stage
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
Life cycle of Giardia
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
Life cycle of Ascaris (round worm)
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
Life cycle of amoeba
parasite
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
 Stool
samples - usually collected X3 and at least
24 hours apart
 Most common preservative = ParaPak (has two
vials, one with Polyvinyl Alcohol [PVA] and the
other with formalin)
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
 “Wet
Prep” for detection of Trichomonas
vaginalis
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Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
Virology
– Characteristics
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Intracellular parasites
Too small to be seen with light microscopy
Contain either DNA or RNA, but not both
Common viral infections include the common
cold, influenza, measles, chickenpox,
hepatitis. Others viral infections include
polio, HIV, bird flu, West Nile virus.
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
– Virus Detection
Most
detected by testing for specific
antibodies (review #5C PowerPoint)
Some viruses can be cultured
– Anatomy of a virus particle – check this
website:
http://www.freebase.com/view/wikipedia/im
ages/en_id/16233765
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Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
Mycology - study of fungus. Infection with fungus
is called a mycosis
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Types of Specimens for Fungal Cultures
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Skin scrapings
Nail clippings
Scalp scrapings
Sputum
Blood
Bone marrow
Lung biopsies
Fungi (plural of fungus) are either “molds” or “yeasts”
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
– Molds - filamentous fungi
Assorted molds culture
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
– Yeasts - unicellular
 Usually
egg-shaped
 Reproduce with buds
 Pasty in appearance
Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
Photos from clinical microbiology
laboratories:
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Unit #5E – Clinical Laboratory
Testing - Basic Clinical
Microbiology
Resources
– Basic Clinical Laboratory Techniques, Estridge and
Reynolds, Thomson/Delmar Learning, Fifth Edition,
2008
– http://www.uphs.upenn.edu/bugdrug/antibiotic_ma
nual/Gram3.htm
– http://www.shellab.com/bactron.html
– http://www.terrauniversal.com/products/glovebox
es/accessories_gbx/filtrationmodules.php
– http://www.freebase.com/view/wikipedia/images/e
n_id/16233765