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148 Cards in this Set
- Front
- Back
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Fastidious bacteria and example |
Microorganism that requires special cultivation measures. Ed: Nisseria and Hemopholus |
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Should specimens be collected before or after initiation of antibiotics? |
Before. |
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What should be considered when to collect a specimen? |
The history and physiology of the disease. |
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What happens when quantity isn't sufficient? |
Held until the health care provider determines which tests should be performed. Specimens are held, not discarded. |
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What isn't recommended for collection and why? |
Swabs because organism could dry out. Never appropriate for anaerobic cultures because the oxygen is toxic. |
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What type of specimen should be transported to lab immediately? |
CSF. |
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What should a label include? |
Patient's full nane, identification number, date and time of collection, room number, and source of collection. |
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Specimens from the upper respiratory tract include: |
Throat cultures, nasopharyngeal cultures, and specimens from the oral cavity. |
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Bacteria found in the upper respiratory tract include: |
Alpha hemolytic streptococci, staphylococcus epidermis, diptheroids, nonpathogenic Nisseria species, some anaerobes, haemophilus species, and a few Candida albicans. |
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Most throat infections are caused by ______. |
Viruses. |
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Most frequent bacterial pharyngitis is _____________. |
Group A strep or streptococcus pyogenes. |
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What type of plate is used for neisseria or haemophilus? |
Chocolate. |
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What is the Nasopharynx cultured with? |
A flexible thin wire swab that has been premoistened with sterile saline. |
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Which type of specimen is preferred for pertussis or Bordetella pertussis? |
Nasopharyngeal. |
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Nasopharyngeal specimens may be used to identify carrier state of ________________________________. |
Staphylococcus aureus or Nisseria meningitidis. |
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Asymptomatic carrier |
Bacteria is present, but doesn't cause infection. Can serve as source of infection. |
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Oral cavity infections |
Gingivitis and dental caries. |
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Common pathogens in ears and sinuses include: |
Streptococcus pneumoniae, haemophilus influenzae, moraxella catarrhalis, and pseudomonas auregenosa. |
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What type of culture is requested for bronchitis and pneumonia? |
Culture of lower respiratory tract. |
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Specific bacteria species associated with pneumonia include: |
Streptococcus pneumoniae, klebsiella pneumoniae, serratia species, pseudomonas aeruginosa, E. coli, Staph aureus, anerobes, and fungi. |
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What bacteria is associated with bronchitis? |
Mycoplasma pneumoniae. |
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Agent of atypical pneumoniae |
Mycoplasma pneumoniae. |
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Specimens that are used to diagnose lower respiratory tract infections include: |
Expectorated sputum, endotracheal specimens, translaryngeal aspirated, and bronchoalveolar lavage. |
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Type of sputum specimen that is recommended |
First morning specimen because it will contain more pooled bacteria. |
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What type of specimens should be rejected as lower respiratory tract collections? |
Saliva, oropharyngeal secretions, and sinus drainages. |
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Bartlett's classification |
Number of neutrophils and epithelial cells per low power field is enumerated. |
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A score of ___ on the bartlett's classification indicates lack of inflammation, while score of greater than ____ indicates inflammation or infection. |
0 or less, 1 or more. |
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What are PMNs associated with? |
Acute bacterial pneumonia. |
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What are AMs and CCs associated with? |
Found in lower respiratory tract and indicate specimen was collected properly. |
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Purulent secretions contain more than ___ PMNs and less than __ SECs. |
25, 10. |
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It is recommended that all specimens containing purulent secretions should be _________, whereas those containing oral secretions should be __________. |
Cultured, recollected. |
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Common bacteria of GI tract |
Salmonella, shigella, campylobacter, vibrio, yersinia, enterocolitica, and E. coli (0157:H7). |
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What is important in determining cause of gastroenteritis? |
History, like what they've eaten and preparation. |
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Transportation of stool specimens. |
Within 24 hours, held at 4 degrees. |
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Lower UTIs may involve ______ or ________. |
Bladder or urethra. |
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Upper UTIs include infections of the _______. |
Kidneys, such as pyelonephritis and glomerulinephritis. |
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What may be infected with an upper UTI? |
Pelvis or ureters. |
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Specimen of choice for a bacterial urine culture |
Clean catch midstream specimen. |
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Most common cause of UTI |
E. coli. |
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Normal bacteria in urine |
E. coli and other members of the enterobacteriaceae (Proteus, enterobacter, klebsiella) Enterococcus faecalis, pseudomonas aeruginosa, staph aureus, and staph saprophyticus. |
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Colony count |
Performed on all urine samples submitted for a bacterial culture. Example, 145 yields 145,000. |
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Bacteremia |
Presence of bacteria in blood. |
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Etiological agents of blood |
Staph aureus, enterococcus, E. coli, and other enterobacteriaceae. |
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Septicemia |
Circulating bacteria multiply faster than phagocytosis can occur, and multiple organ failure can occur. |
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Transient bacteremia |
Normal flora introduced into the blood. |
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Intermittent bacteremia |
Bacteria are sporadically discharged from extravascular abscesses into the blood. |
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Continuous bacteremia |
Constant release of bacteria into the blood. May occur with subacute bacterial endocarditis. |
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Collection of blood cultures |
Proper skin preparation is essential. Collect 2-4 cultures from separate sites up to an hour apart. If choice of bottle, use aerobic. 20 ml of blood needed. No more than 3 sets per 24 hours. |
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Color of normal CSF |
Clear and colorless. |
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Etiological agents of CSF |
Neisseria meningitidis, haemophilus influenzae, and streptococcus agalactiae (group B strep). |
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Collection of CSF |
Needle aspirate from the 3rd or 4th lumbar vertebra. 3 tubes, typically use the 3rd tube. Process and work immediately because m/o would be fastidious. |
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What temp can CSF be held at? |
Up to 6 hours at 37 for bacteria and 4 degrees for virus detection. |
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Etiologic agents of genital tract |
Neisseria gonorrhoeae, treponema pallidum, herpes simplex virus type 2, chlamydia trachomatis, and trichomonas vagnialis. |
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N. gonorrhoeae requires ________ to grow. What type of plate should be used? |
Chocolate. Martin Lewis or modified Thayer Martin because of the abundance of normal flora. |
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Where can specimens be collected with the genital tract? |
Urethral exudate, uterine cervix, and urethra. |
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Etiological agents of wounds and abscesses |
Staph aureus, enterococcus, anerobes, and fungi. |
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Collection of wounds and abscesses |
Aspirates, irrigation fluids, purulent drainage, and necrotic tissue. Recommended needle aspirates and not swabs. |
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Exogenous wound infections |
Result from animal and human bites, burns, ulcers, and traumatic wounds. |
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Endogenous wound infections |
Attributed to indigenous bacterias within patient including cellulitis, dental infections, and septic arthritis. |
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Goal of specimen transportation |
Maintain specimen in its original state. 2 hour limit. If delay anticipated, use transport media such as Amies or Stuarts. |
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What happens when a specimen is received at lab? |
Log in and evaluate, notify healthcare provider of any concerns. Gross examination of color, volume, and appearance. |
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Usually, gram ______ is a pathogen in cultures. |
Negative. |
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Which type of cell is related to infection? |
Neutrophils. |
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Which cells are related to contamination? |
Epithelial. |
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General isolation media and examples |
Aka supportive media. Supports growth of most nonfastidious bacteria. Ex: nutrient agar, t soy agar, and nutrient broth. |
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Nonselective isolation media and examples |
Aka enriched media contains nutrient supplement. Ex: sheep blood agar and chocolate agar. |
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Alpha hemolysis |
Incomplete, greening or browning of the medium. |
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Beta hemolysis |
Complete, total clearing of the medium. |
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Nonhemolytic hemolysis |
No change in color of the medium, may be referred to as gamma hemolysis. |
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Chocolate agar |
Red cells are hemolyzed by enzyme or heat to release NAD and hematoma. Enriched with IsoVitaleX and other nutrients. Isolates fastidious bacteria such as haemophilus and Nisseria. |
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Differential media and examples. |
Provides a distinct colonial appearance. Isolates one group of bacteria. Also known as selective differential. Ex: maconkey and eosin methylene blue. Isolates gram neg. |
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If the organism can ferment lactose, the colonies appear ________ or ________. Non lactose fermenters appear _____. |
Pink or red. Clear. |
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MacConkey Agar |
Isolates gram neg. differentiates lactose fermenters from non lactose fermenters. |
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MacConkey Agar |
Isolates gram neg. differentiates lactose fermenters from non lactose fermenters. |
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What type of media is EMB and what are its characteristics? |
Isolates gram - . Differential media. |
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MacConkey Agar |
Isolates gram neg. differentiates lactose fermenters from non lactose fermenters. |
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What type of media is EMB and what are its characteristics? |
Isolates gram - . Differential media. |
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Color of EMB lactose fermenters |
Strong lactose fermenters: green metallic sheen such as E. coli. Lactose fermenters: purple Nonlactose: clear |
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Enrichment broth |
Inhibits growth of one group of bacteria and enhances growth of another. |
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Gram negative broth, selenite broth, tetrathionate broth |
Inhibit normal flora of colon to enhance growth of stool pathogens. |
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Thioglycollate broth |
Differentiation of aerobes and anaerobes. |
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Selective media |
Inhibit growth of all bacteria except those being sought. Inhibit normal flora. |
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Thioglycollate broth |
Differentiation of aerobes and anaerobes. |
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Selective media |
Inhibit growth of all bacteria except those being sought. Inhibit normal flora. |
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HE (Hektoen Enteric), SS (Salmonella-Shigella), and XLD (Xylose Lysine Deoxychocolate) and what type of media? |
Inhibit normal flora of colon, enhance isolation of stool pathogens, and differentiate based on ability to ferment carbs. Inhibit gram +. Selective media. |
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HE: organisms that ferment carbs and don't ferment ----> color |
Yellow: ferment Non fermenter: green/blue Differentiation of sulfide producing bacteria: black. Usually indicates salmonella. |
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Antibiotic media |
Selective for a group of bacteria through the addition of specific antibiotics. |
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CNA media and what type? |
Blood agar with antibiotics added. Selects for gram pos and inhibits gram neg. Antibiotic media. |
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Modified Thayer Martin (MTN) and Martin Lewis media and what type? |
Chocolate agar with antibiotics added. Selects for Nisseria gonorrhoeae and inhibits gram positive bacteria and other gram neg. antibiotic media. |
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Human pathogens grow best at _______ degrees. |
35 plus or minus 2. |
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Modified Thayer Martin (MTN) and Martin Lewis media and what type? |
Chocolate agar with antibiotics added. Selects for Nisseria gonorrhoeae and inhibits gram positive bacteria and other gram neg. antibiotic media. |
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Human pathogens grow best at _______ degrees. |
35 plus or minus 2. |
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Most bacteria are __________ preferring a growth temp of ___________. |
Mesophillic, 25-40. |
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Thermophiles |
Prefer growth of 40 or higher. |
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Thermophiles |
Prefer growth of 40 or higher. |
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Psychrophiles |
Prefer growth at low temps such as 4-20. |
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Strict or obligate aerobes |
Absolute oxygen requirement. |
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Facultative anaerobes |
Can multiply in presence or absence of oxygen |
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Facultative anaerobes |
Can multiply in presence or absence of oxygen |
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Strict or obligate anaerobes |
Unable to multiply in presence of oxygen. |
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Capnophillic |
Prefer growth in presence of c02. |
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How is a co2 environment achieved? |
Using a candle jar. |
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Oxidation |
Use of carbs in the presence of oxygen. |
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Oxidation |
Use of carbs in the presence of oxygen. |
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Fermentation |
When a carb is used in the absence of oxygen. |
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What part of the tube is fermentation read from? |
Deepest part of the tube. |
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Where is oxidation read from tube? |
Uppermost part of the tube. |
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Catalase |
Enzyme that breaks down hydrogen peroxide by converting it to water and oxygen. (Bubbles) |
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Catalase |
Enzyme that breaks down hydrogen peroxide by converting it to water and oxygen. (Bubbles) |
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What is catalase important in differentiating? |
Staphylococcus (+) from Streptococcus (-) and Bacillus (+) from Clostridium (-). |
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Production of catalase, process, and results. |
Phagocytosis doesn't work well because of hydrogen peroxide. Inoculate 3% hydrogen and look for bubbles. Bubbles = positive. |
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Coagulase and differentiation. |
Fibrinogen is converted to fibrin. Differentiates staph aureus from coagulate neg staphylococcus. |
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Coagulase test and results. |
Clumping is positive. Mix colony with drop of rabbit plasma. |
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Coagulase test and results. |
Clumping is positive. Mix colony with drop of rabbit plasma. |
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Cytochrome oxidase and what is it found in? |
Oxidizes oxidase reagent in presence of oxygen to form indophenol. Found in: Nisseria, pseudomonas, campylobacter, aeromonas, and pasturella. NO ENTEROBACTERIACEAE. |
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Coagulase test and results. |
Clumping is positive. Mix colony with drop of rabbit plasma. |
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Cytochrome oxidase and what is it found in? |
Oxidizes oxidase reagent in presence of oxygen to form indophenol. Found in: Nisseria, pseudomonas, campylobacter, aeromonas, and pasturella. NO ENTEROBACTERIACEAE. |
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Results of oxidase test |
Positive = purple. |
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Spot Indole test and results |
Detects enzyme tryptophanase which breaks down tryptophan when bacteria are grown on blood agar or chocolate agar. Smear filter paper that has been saturated with Kovach's reagent across colony. Pink/red is positive. |
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Spot Indole test and results |
Detects enzyme tryptophanase which breaks down tryptophan when bacteria are grown on blood agar or chocolate agar. Smear filter paper that has been saturated with Kovach's reagent across colony. Pink/red is positive. |
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What is the spot Indole test important in differentiating? |
E. coli from other lactose fermenting enterobacteriaceae. Proteus mirabilis (-) from proteus Vulgaris (+). |
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PYR hydrolysis is important in differentiating: |
Group D streptococcus (+) from non enterococcus (-). Beta hemolytic streptococcus: Group A (+) from group B (-). |
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PYR hydrolysis is important in differentiating: |
Group D streptococcus (+) from non enterococcus (-). Beta hemolytic streptococcus: Group A (+) from group B (-). |
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Saline mount |
Aka wet mount. Motility and presence of bacteria. |
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Iodine mount |
Used to stain stools for parasitic ova whose nuclei appear orange to brown. Parasites. |
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Iodine mount |
Used to stain stools for parasitic ova whose nuclei appear orange to brown. Parasites. |
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KOH |
Detects fungal elements. |
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Iodine mount |
Used to stain stools for parasitic ova whose nuclei appear orange to brown. Parasites. |
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KOH |
Detects fungal elements. |
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India Ink or Nigrosin |
Detects capsules. |
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Neufeld Quelling Reaction |
Capsular swelling for bacterial capsules. |
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Simple stain vs differential stain |
Same color to all structures. Contains more than 1 dye and impart different colors to various structures. |
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Methylene blue |
Simple stain. Observe size, shape, and morphology. |
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Methylene blue |
Simple stain. Observe size, shape, and morphology. |
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Gram stain Crystal violet Gram's iodine Ethyl alcohol Safrinin |
Differentiates gram pos and gram neg. Crystal violet: primary stain Iodine: mordant Ethyl alcohol: gram pos retain because of the peptidoglycan and teichoic acid cross links. Gram neg lose primary stain because of large amount of Lipopolysaccharides in wall. Safrinin: Counterstain. |
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Methylene blue |
Simple stain. Observe size, shape, and morphology. |
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Gram stain Crystal violet Gram's iodine Ethyl alcohol Safrinin |
Differentiates gram pos and gram neg. Crystal violet: primary stain Iodine: mordant Ethyl alcohol: gram pos retain because of the peptidoglycan and teichoic acid cross links. Gram neg lose primary stain because of large amount of Lipopolysaccharides in wall. Safrinin: Counterstain. |
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Color of gram pos and gram neg |
Pos: pink or red Neg: purple |
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Coccobacilli |
Very short bacilli. |
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Coccobacilli |
Very short bacilli. |
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Fusiform bacilli |
Taper at both ends. |
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Ex of diplococci |
Strep pneumo: lancet shaped. Neisseria is kidney shaped. |
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Curved bacilli ex |
Campylobacter. Resembles seagull wings. |
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Curved bacilli ex |
Campylobacter. Resembles seagull wings. |
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Coccobacilli ex |
Haemophilus. |
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Acid fast stains |
Used to stain mycobacterium. |
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Fluorescent stains |
Rhodamine auraminee, acridine Orange, and calcoflour white. |
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What could be the cause of error with gram stain if the slide is all pink? |
1. Over decolorization. 2. Didn't let primary stain sit long enough. 3. Flooded it. |
