Term
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Definition
| plant-like org-m --- yeast and mold |
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Term
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Definition
| invertebrate oranisms; may serve as Dz vector |
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Term
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Definition
| classification of parasitic worms |
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Term
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Definition
| microorganisms residing in healthy host |
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Term
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Definition
| organisms capable of producing Dz or illness |
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Term
| define Opportunistic infection – |
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Definition
| causes Dz in host w/weaken immune system |
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Term
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Definition
| motile, animal-like single celled org-ms, classified by locomotion |
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Term
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Definition
| depend upon another organism for survival which it receives at the expense of host |
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Term
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Definition
| non-living organism dependent on another cell for replication |
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Term
| areas of microbiology (list 5): |
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Definition
Bacteriology –
Virology –
Mycology –
Parasitology –
Serology (+/-) – |
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Term
| what technique is used for specimen collection? |
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Definition
- Aseptic or “sterile” technique --- Avoid contamination
- Specimen site
o Site appropriate for type of study
o Proper medium and collection apparatus |
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Term
| specimen collection: what is important about transport, specimen processing and interpretation results? |
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Definition
Transport media --- support microbial viability during transit
Anaerobic specimens require special transport and maintenance media
Specimen processing: label properly (inoculation incubation ,temperature, CO2)
Dx-ic relevant test --- proper Dx test based upon S/S
Interpretation of results -record correctly – 80% lab error d/t clerical error!!! |
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Term
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Definition
- helps Preliminary measure of org-ms
- Method of chemically staining specimens, ientifying org-ms by staining results along w/morphology |
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Term
| what are the major steps in gram stain? |
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Definition
- Prep slide w/body fluid/specimen
- Heat for seconds
- Apply 1’ stain crystal violet for 1 minute
- Apply mordant; Gram’s iodine for 1 minute
- Wash w/ acid EtOH
- Apply counterstain; saffarin for 1 min
- Wash with H2O (~5 seconds)
- View under microscope |
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Term
| what can you examin under low power (10x)? |
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Definition
- Note PMNs, epithelial cells
- Note quality of smear |
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Term
| what can you examin under high power - oil immersion(100x)? |
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Definition
- Note microbial elements
- Scan several fields
- Quantities (few, many, or numeral grade)
- Patterns
- Results are subjective |
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Term
| what is culture media? list some properties: |
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Definition
- Nutrient media of various composites and additives
- Selective or isolative
- Enrichment
- Maintenance
- Liquid, solid or semisolid consistency
- Transport |
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Term
| list Bacterial Culture Media |
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Definition
| Blood Agar Medi: Sheep’s Blood Agar (SBA), Chocholate Agar - Thayer Martin: GC Agar/plate Agar - MacConkey Agar:Inhibits Gram(+)s, pH color indicator - Tryptic Soy Agar/Broth: grow on pure Cx |
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Term
| What are sources of error in gram stain prep? |
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Definition
| - Sources of error: poor slide making ; failure to heat fix slide; overheating; expired reagents; over- or under-decolorizing slide; contaminated reagents w/microorganisms; operator interpretation |
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Term
| list other methods to differentiate bacteria (not gram stain) |
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Definition
o Biochemical and Enzyme Testing: Catalase, Oxidase, Coagulase (clot=”+”), Citrate
o Automated
o Serological methods: PCR
o Immunoassays |
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Term
| Serological methods: PCR allow the following: |
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Definition
DNA probe (nucleic acid)
Genetic id-n of microbes
Rapid multiplication of DNA sequence
GC/Chlamydia probe |
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Term
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Definition
Biochemical test that measures the concentrationn of a substance in a biological liquid: e.g. serum or urine
Specific binding of an Ab --> antigen
Reference lab test
Expensive !!!
Enzyme-linked immunosorbent assay (ELISA) --> RMSF --- Scarlet Fever
Fluorescent Ab test
Antigen-Ab test --> rapid Strep
Latex agglutination --> Syphillis Fast (new) |
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Term
| Microbial Classification - Taxonomy: |
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Definition
| classification, nomenclature, laboratory, identification |
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Term
| Microbial Classification - Gram Positive |
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Definition
| Aerobic bacilli and aerobic cocci |
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Term
| Microbial Classification - Gram Negative |
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Definition
| Aerobic cocci, aerobic rods, Nonfermentors |
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Term
| Microbial Classification - anaerobes |
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Definition
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Term
classify as G(+)/(-):
o Aerobic cocci: Streptococcus, Staphylococcus, Enterococcus (prev. gr D Streptococcal) |
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Definition
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Term
classify as G(+)/(-):
Rods or bacilli: Corynebacteria, Listeria monocytogenes, Nocardia, ; Bacillus anthracis (Anthrax) |
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Definition
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Term
classify as G(+)/(-):
anaerobs (survive in GI) - Actinomycetes – branching organism; Lactobacillus; Clostrodium species (C. tetani, C. difficile, C. perfringens, C. botulinum) |
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Definition
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Term
classify as G(+)/(-):
o Aerobes bacilli or rodes ---
Pseudoonadacae Pseudomonas aeruginosa
Bordetella pertussis
Helicobacter pylori
Legionella pneumophila |
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Definition
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Term
classify as G(+)/(-):
o Rods – Facultative anaerobes – Enterobacteriaceae: large Gram(-) rods, assoc-d w/GI infections
Escherichia coli – common encountered pathogen, NML flora in gut
Klebsiella – mucoid colonies, capsule !!! (hard to treat)
Proteus species – stinks badly
Obligate aerobe – Vibrionaceae (Vibrio cholerae)
Facultative anaerobic - pasteurellae: coccobacilli, Haemophilus influenza, P. multocida |
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Definition
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Term
classify as G(+)/(-):
Cocci: Neisseriaeae – Neisseria meningitides – aerobic |
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Definition
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Term
classify as G(+)/(-):
o Obligate IC parasites: Richettsiae, Rocky Mountain Spotted Fever |
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Definition
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Term
Classify as G(+)/(-):
o Anaerobes: Bacteroidaceae (Bacteriodes fragilis); Fusobacterium (F. nucleatum) |
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Definition
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Term
Classify as G(+)/(-):
o Spirochetes (Treponema pallidum - syphillis); Mycobacteria (Mycobacterium avium, M. tuberculosis) |
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Definition
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Term
Classify as G(+)/(-):
o Chlamydia (bacteria):
Obligate IC org-m: class-d as bacteria (phylum Chlamydiae); replicates IC-ly, smaller than viruses
Respiratory and sexual transmitted infections |
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Definition
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Term
| is Cryptococcus neoforma G(+) or G(-)? |
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Definition
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Term
| list common microbial cultures specimen types: |
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Definition
| -Bloos Cx - Respiratory Cx - Tissue Cx - Body fluid Cx (pleural fluid, CSF, peritoneal fluid) - urine Cx) |
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Term
| Blood Cx: indications, collection, process... |
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Definition
o Indications: detect presences of bacteria in blood; suspicion of bacteremia, sepsis or endocarditis; assess after antimicrobial Tx initiated
o NML ranges: NO growth after 5 Days
o Collection: 2 sets (aerobic/anaerobic) from 2 different sites or times
Peripheral access preferred
Volume dependent
Skinn prepped with Povidine-iodine
Blood Cx bottle or test tube also cleansed
o Process: Automated sys-m of detection; id-n & antimicrobial sensitivities takes longer time;
False Positives --- Contaminants |
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Term
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Definition
o Indications: Dx & eval pulmonary related illness suspected to be of infxs etiology; pts w/risk factors
o Specimen culturing methodology & testing divided by location in pulmonary tree: UR, LR
o NML ranges: no growth or NML flora
o UR Cx or rapid test: nasopharyngeal swab or aspirate (wash)
Specimen from secretions of the upper-most part of the throat
Dacron or rayon swab
Wash w/sterile saline in < 2 yo
Immediate transport LAB
Id viruses or bacteria: RSV, Influenza A/B, Bordetella, Staphylococcus carriers
Throat swab --- specimen often obtained by provider --- rapid streptest:
• Commercially available immunoassay
• Highly specific & sensitive
• Group A β-hemolytic streptococcus or Streptococcus pyogenes
• Cx still gold std for strep Dx: SBA, id-ing β-hemolysis on agar
o LR Cx
Sputum /Tracheal aspirate (sputum is worthless!!! Per Ferguson)
Gram stain screening for “acceptability”:
• Contamination 10-25 squamous epithelial cells
• Low yield specimen rejection or report or NML flora
Other common analysis:
• Acid fast stain: TB smear; incl-d w/TB Cx; Carbol Fuschin Stain
• Acid fast bacillus (AFB) Cx:
o Mycobacterium tuberculosis
o 3 respiratory specimens
o 2-4 wks for init, res-ts
o Id-n of AFB w/DNA probes faster yield |
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Term
| Urine Culture: indications, colection, ranges, sensitivity... |
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Definition
- Indications: Dx or confirm UTI, screening in early pregnancy, pts w/risk factors
- Collection: clean catch specimen or sterile collection; sterile container
- Bacteria in suprapubic catheterized specimen is significant
- Urine Cx and Sensitivity: results measured over 48 hrs
Id-n of microorganisms
~Lab will test up to 2 org-ms: E. coli causes ~80% of infections (non indwelling catherized pts)
Susceptibility or sensitivity testing takes longer --- guide to antimicrobial Tx |
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Term
| What is Antimicrobial Susceptibility Testing(aka sensitivity testing or drug resistance testing)and what are indications? |
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Definition
- Determines the likelihood that an antimicrobial will be effective in eliminating or inhibiting the growth of the infection
- Indications: guide antimicrobial Tx; nrrow antimicrobial Tx to appropriate agents; decrease med. costs |
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Term
| Waht is the methodology of Antimicrobial susceptibility testing? |
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Definition
o Kirby Bauer disk agar diffusion
o Broth serial dilution or broth microdilution
o Automation --- rapid results 12-20 hrs |
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Term
| How are results of Antimicrobial Suseptibility testing reported? |
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Definition
o Zones of inhibition are interpreted for a microbe based upon when exposed in vitro to a antimicrobial agent at specific conc-n
o Susceptible, Indeterminate and Resistance
o Qualitative and Quantitative measurements
o MIC
o MBC |
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Term
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Definition
– Min. Inhibitory Conc-n:
Lowest antimicrobial conc-n of antimicrobial agent req-d to inhibit a microorganism
Methods: (1) serial broth dilution; (2) Agar dilution |
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Term
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Definition
– Min. Bactericidal Conc-n --- aka min. lethal conc-n (MLC)
Max dilution of the product that will kill a microbe can be determined by subculturing last clear MIC tube onto growth medium and examining for bacterial growth |
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Term
| How viruses can be detected? |
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Definition
| - Viruses can detected by cytopathic effect, Ab staining, antigen detection, DNA probes, electron microscopy |
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Term
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Definition
- Serologic Dx-ic testing for viral Dz: Monospot:
o Heterophile Ab test
o “mono” – EBV
o < Sensitivity in young children
o Blood specimen |
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Term
| what is "cytopathic effect"? |
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Definition
o Shut down of cell fxn
o Cell transformation: changes in IC structure; viral inclusion bodies; malignant cell changes
o SARS (Conovirus) vs unaffected – |
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