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)

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.

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

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology Cocci/Diplococci Bacilli/Rods

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology Spirochetes

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology Gram Stain http://www.uphs.upenn.edu/bugdrug/antibiotic_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

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology Gram Positive Cocci

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology Gram Positive Bacilli Gram Negative Cocci

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology Gram Negative Bacilli

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

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

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

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

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology Sterilization - methods used to kill all organisms and their resting stages EXAMPLE: Autoclaving

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

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

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology Selective agars – Inhibit the growth of certain microorganisms while allowing other organisms to grow

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

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

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology Life cycle of Giardia

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology Life cycle of Ascaris (round worm)

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology Life cycle of amoeba parasite

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)

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology “Wet Prep” for detection of Trichomonas vaginalis

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.

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/studentwork/2006/WB_SC_Rimbakusumo/wworks.html

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”

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology Molds - filamentous fungi Assorted molds culture

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology Yeasts - unicellular Usually egg-shaped Reproduce with buds Pasty in appearance

Unit #6E – Clinical Laboratory Testing - Basic Clinical Microbiology Photos from clinical microbiology laboratories: