Unit

1
Unit 6E Clinical Laboratory Testing Basic
Clinical Microbiology

• Includes study of bacteria (bacteriology),
  parasites (parasitology), viruses (virology) and
  fungi (mycology)
• Cecile Sanders, M.Ed., MT(ASCP),
• CLS (NCA)

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Bacteriology
• 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.

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Bacterial Microscopic Morphology
• Coccus - round (cocci plural)
• Example Streps, staphs, Neisseria
• Diplococcus - cocci in pairs (diplococci
  plural)
• Example Strep. pneumoniae
• Bacillus or rods - parallel sides (bacilli
  plural)
• Example E. coli
• Spirochetes - curved or spiral organisms
• Example Treponema pallidum

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Cocci/Diplococci
• Bacilli/Rods

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Spirochetes

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Gram Stain http//www.uphs.upenn.edu/bugdrug/antib
  iotic_manual/Gram3.htm
• 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
• Purpose of Gram Stain Provides valuable
  information for physician to start antibiotic
  therapy, as antibiotics act differently on gram
  () vs. gram (-) organisms

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Gram Positive Cocci

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Gram Positive Bacilli
• Gram Negative Cocci

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Gram Negative Bacilli

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Clinical Bacteriology Terms
• 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 6E 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

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Unit 6E 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/products/gloveboxes
  /accessories_gbx/filtrationmodules.php

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Unit 6E 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
• EXAMPLE 10 bleach, phenols
• Antiseptics - chemicals used to control
  microorganisms on living tissue
• EXAMPLE 70 isoprophyl alcohol, Betadine

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Sterilization - methods used to kill all
  organisms and their resting stages
• EXAMPLE Autoclaving

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Processing of Specimens
• Agars - solid medium made of seaweed extract
• Enrichment agars for growth contain extra
  nutrients
• Example Blood Agar

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Unit 6E 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

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Selective agars Inhibit the growth of certain
  microorganisms while allowing other organisms to
  grow

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Unit 6E 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 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Parasitology
• Common human parasites
• Enterobius vermicularis Pin Worm
• Giardia lamblia
• Trichomonas vaginalis
• O P (Ova and Parasites) - Detection of
  Intestinal Parasites
• Helminths - flatworms, round worms, flukes, or
  hookworms
• Amoeba in cyst or trophozoite stage

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Life cycle of Giardia

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Life cycle of Ascaris (round worm)

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Life cycle of amoeba
• parasite

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Unit 6E 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)

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Wet Prep for detection of Trichomonas vaginalis
  

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Virology
• Characteristics
• 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.

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Virus Detection
• Most detected by testing for specific antibodies
  (review 6C PowerPoint)
• Some viruses can be cultured
• Anatomy of a virus particle check this website
• http//www.nwabr.org/studentbiotech/winners/studen
  twork/2006/WB_SC_Rimbakusumo/wworks.html

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Mycology - study of fungus. Infection with
  fungus is called a mycosis
• Types of Specimens for Fungal Cultures
• Skin scrapings
• Nail clippings
• Scalp scrapings
• Sputum
• Blood
• Bone marrow
• Lung biopsies
• Fungi (plural of fungus) are either molds or
  yeasts

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Molds - filamentous fungi
• Assorted molds culture

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Yeasts - unicellular
• Usually egg-shaped
• Reproduce with buds
• Pasty in appearance

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Unit 6E Clinical Laboratory Testing - Basic
Clinical Microbiology

• Photos from clinical microbiology laboratories