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60 Cards in this Set
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Tuberculosis basics |
Aerobic G+, slightly curved or straight bacteria, in beaded chains that may branch. Non-motile, Urease +
Cell wall is made of Mycolic Acid and Waxes, hard to satin and requires acid fast.
Grows at 35-37c over 6-8 weeks in 5% CO2, also loves fatty acids (egg yolks), some may require iron or Hemian |
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Tuberculosis Specimen collection |
Take early morning sputum for three consecutive days. Two positive smears, are diagnostic for some form of Tuberculosis.
A gastric aspirate is often performed on children.
Samples are invalid after 1 hour unless kept at 4c
Plate onto Middlebrook Agar 7H11 to enhance M. bovis, 7H10 contains Hemin for M. haemophilum
Or plate on Egg based medium (Loewenstein-Jensen agar
Dose not require transport medium. |
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Tuberculosis General Pathology |
Patients with HIV/AIDS or are otherwise immunocompromised are at the greatest risk in the U.S.
Upon inhalation MTB enters macrophages and multiplies. From there it spreads to the LN, and begins damaging epithelial tissue and macrophages by forming granulomata and multinucleated Langerhans cells.
Granulomata fills the tissue with holes leading to cavitation. This damage is healed by forming fibrous tissue and calcifying the area. |
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Tuberculosis Treatment |
1st: Isoniazid (INH) & Rifampin (RIF)
2nd: Pyraziamide (Z) & Ethambutol (E)
Treat with 4 drugs for 2 months, or 2 drugs for 4-7 months.
LTBI can be treated with a singular drug (INH) over 9 months. |
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Tuberculosis Infection Paths |
Only found in humans and spread by aresoles (coughing and sneezing) |
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Tuberculosis Drug Resistance |
Multidrug Resistance MDR TB: Resistant to Isoniazid and Rifampin
Extensivly Resistant: Resistant to Isoniazid, Rifampin, and one 2nd line drug. |
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Tuberculosis Diagnosis |
Chest X-rays reveal damage.
Tuberculin Skin Test (TST) AKA: Mantoux test or Purified Protein Derivative (PPD); 5 units of tuberculin are injected intradermally and the skins raising in response is measured.
IFN-gamma release test: Heperinized blood -Quantiferon Gold: stimulation with ESAT-6 and CFP-10, quantifies IFN-gama released by T-cells
-T-Spot TB (elispot): Counts number of T-cells releasing IFN-gama
Blood tests are overall more accurate, but harder to perform.
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Ziehl Neelsen & other stains |
Ziehl Neeslen is an Acid-Fast Stain: It is made of Carbo Fuschin and heat fixed at 65c over 2 hours and then counter stained with Methyl-Blue. Smear positive patients are highly infectious and more likely to die. Look for Cording of the bacteria.
Kinjoun stain: Fix with Phenol instead of heat
Auramine Rhodamine: view under 20x or 40x
Modified AF stain: 1% sulfuric acid |
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M. Tuberculosis Testing |
Look for Dry, pale, crumbly colonies
12-25 days to grow.
Visible cording microscopicly
Niacin accumulation (yellow color)
Nitrate reduction
Pyrazinamidase +
Weakly catalase + up to 68c |
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M. Bovis Testing |
Niacin-
Nitrate -
Pyrazinamidase - |
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BCG Vaccine |
Bacille Calmette-Guérin
Dose not prevent infection, but limits it's ability to spread by 20-80% |
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Tuberculosis Symptoms |
90% of infections are aysymptomatic
Pulmonary is most common with: Cough, Hemoptysis (Bloody Sputum), fever, malasia, night sweats and weight loss.
TB can extra pulmonary and occur nearly anywhere in the body. The most common is Cervical Lymphadentitis (Scrofula) 25% of cases. |
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Sputum Protocol |
Add 4% NaOH for 20 minutes or NALC+2%NaoH
For CF use 5% Oxalic acid
Spin 20 seconds at 3000g
Discard most SN, and resuspend pellet in about 2-5mL
Contamination should be no more than 3-5% Stop decontamination with 2x PBS
Heat fix to slide and kill TB with a bleach solution and then stain |
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M. tb-AST |
Bactec460: Routine liquid radiometric ¤ 7H12 medium + radiolabeled (C14 O2) palmitic acid ¤ Scintillation counter – gives growth index ¤ >10 equals growth
Agar Proportion method ¤ >1% growth compared to control => resistance ¤ >6-10% growth compared to control => drug adds nothing
MGIT: Mycobacteria Growth Indicator Tube
Direct microscopic observation (sens. >90% and fast turnaround – less than 10 days)
Molecular Tests – Lineprobe Assay
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M. leprae Infection Paths |
9-banded armodillo is the carrier. |
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M. Leprae Pathology |
Causes chronic granulomatous and Anesthic skin lesions and peripheral neuropathy. |
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M. Leprae Specimen Collection |
Can not be cultered |
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What are NTM? |
Non-Tuberculoid Mycobacterium.
Divided into rapid growers (less than 7 days), and slow growers (More than 7 days) |
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NTM basics |
Aerobic, Non-motile, Thick Walls, Many are acid fast, can not spread between people
Often spread by tap water.
Pulmonary infections are the most common at 75% of all cases (MAC, kansasii, absecessus, xenopi) |
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Photo- Vs Scotochromogens |
Photo = Produces yellow pigment only when exposed to light.
Scoto = Produces yellow pigment in the light or dark.
Non-chromogens do not produce pigment. |
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Runyon Classification of NTM |
Group I = Photochromogens
Group II = Scotochomogens
Group III = Nonchromogens
Goup IV = Rapid-Growers |
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NTM species in each group |
I = Kansasii (Yellow) & Marinum
II = Gordonae (yellow), Szulgai & Scrofulaceum
III = MAC, Haemophilum (28-30c), Ulcerans & Xenopi (42c)
IV = Fortuitum, Chelonae, Abscessus, Mucogenicum (No pigment), Smegmatis (Non or Late pigment) |
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Microscopic Xenopi |
Long, Thing, and Floaty |
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Group Microscopy |
I = Chaotic, long and fat Acid-fast
II = Beaded with pointed ends and pallisade, also Acid fast
III = Very evenly dispersed (Tiles), pleomorphic or coccobacilli
IV = Poorly staining and Chaotic |
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Catalase & Catalase at 68c |
>45mm = positive (high)
~45 mm = Positive
<45mm = Negative
At 68c
No bubbles = negative
+ = Scant bubbling ++ = Bubbles on the whole buffer surface +++= 1cm of bubbles ++++ = 5+cm of bubbles
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Pyrazinamidase test |
M. marinum produces a bright red band in the viles center. Other wise the test is a straw yellow. |
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Tween 80 Hydrolysis |
Positive = Pink/Red color within 10 days
Negative = Maintains yellow color
Control/Weak Positive = Orange color |
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Iron Uptake Test |
Positive = Colonies turn a rust color and discolor the medium.
Negative = Normal colored colonies on a blue medium |
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General Anarobe infection Signs |
Crepitance - Gas in tissues
Necrotic flesh and a putrid smell
Mucosal Abscess |
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Anarobe specimine |
Transport stability is less than 2 hours
Regect samples taken from the throat, ETT, Urine from a catheter, or cervical swabs, and swabs in general. |
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Anarobe Culture |
Cultur medium should be PRAS; Pre-Reduced Anaerobicly Stabalized
Can be kept at 36c for 5 days, but do not open for 48 hours
An anaerobic enviroment is 80% N2 / 10%CO2 / 10% H2
Anaerobic conditions can be checked with a methylene blue test.
2-3 weeks of growth to identify |
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Clostridium tertium Pathology |
Commensel: Found of the skin, GI tract and enviroment
Enterotoxin A: Diarhea
Cytoxin B: Colitis |
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Clostridium tertium Testing |
Cat -, Spore forming, Gram variable, Short or long coccoids, Ox -, Butyric Acid +
Yellow, ground-glass colonies that glow
Neurotoxin B can be detected with EIA or NAAT, this is diagnostic |
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Propionibacterium spp Pathology |
Spread by animal bites, surgery, being immunocompromised, and infects the skin, eye, bones and joints |
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Propionibacterium spp Testing |
No spores, Air-tolerant, Cat+
Colonies are tiny and opaque with a gold tinge
Bacteria are slightly curved and Pleomorphic
Aerotolerant, Cat + |
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A. viscosus/neuii Testing |
No Spores, Air Tolerant, Cat + |
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Actinomyces Pathology |
Causes a granulomatous infection leading to swollen abscesses in the mouth, lungs and GI tract. |
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Actinomyces Treatment |
Penicillin susceptible, but Metronidazole resistant. |
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Actinomyces Testing |
No Spore, Air tolerant, Cat - |
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Bifidobacterium Testing |
No Spore, Air tolerant, Cat - |
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Lactobacillus Testing |
No Spore, Air tolerant, Cat - |
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Clostridium perfringens Pathology |
Exoenzymes: Lecithinase (alpha-toxin), lyses mammal cells, includes collagenase and hyalurodinase
Causes Myonecrosis (gas gangrene) |
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Clostridium perfringens Testing |
Long rectangular bacteria, spores are rare.
Produces a distinct double zone hemolysis
Reverse CAMP+, Lecithinase + on egg yolk agar (EYA)
Grows at 42c and is an obligate anareobe |
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C. botulinum Neurotoxin |
Bind the presynamptic of the motor neurons in the peripheral nervous system where they inhibit the release of acetylcholine.
Causes flacid paralysis, associated with floppy baby syndrome, contracted by giving honey to babies. |
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C. tetani Neurotoxin |
Tetanus toxin: Bind the receptors of the presynaptic motor neuron, but migrates to the spinal cord where it binds inhibitory neurons
Inhibits the release of GABA/glycine, causing uncontrollable contraction (spastic paralysis) and lock jaw.
may cause cardiac falure |
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Actinomyces israeli Testing |
Variable colony morphology, but develops a Molar tooth like appearance after a few weeks.
Clubshaped (diphtheroid), may or not be branched, but always beaded
Not stained by acid fast
Cat -, Urease -, Nitrate +, Esculin +
Produces "sulfur granules" (yellow clumps) and is aero-tolerant
Digests sucinate |
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A. odontolyticus |
Red pigment on BHI plate after a few days |
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Propionibacterium propionicum |
Branched, beaded cocci, with a dry colony
Cat -/ Indol - / Nitrate +
Obligate anaerobe
FA test needed to see if propionic or succinic
Causes: Actinomycosis, Endocarditis, Osteomyelitis, Arthritis |
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Propionibacterium acnes |
Most common anaerobic G+ and is normal flora of the skin, nose, mouth and GI
Coryneform (Bird wings)
Pleiomorphic, Cat +, Indol +
Causes Endocarditis, CNS shunt infections, and Acne |
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What medications treat anaerobes |
Beta-lactams (penicillin S)
Metronidazole S except Actinomyces, Propionibacterium, Lactobacillus, Bifidobacterium |
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Peptostreptococcus |
SPS susceptible / Indol -
Identified based on fatty acids it can digest, but this is not needed, just report as G+C
Anaerobic |
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Veillonella |
Infects the mouth, URT, intestines and GU
Causes endocarditis, and bacteremia
Vanco R, produces propionic acid, some have red glow |
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Bacteroides fragilis |
Very common isolate
A pleomorphic G-
Causes intrabdominal abscesses and bacteremia
ID: Mucoid/Shiny, Cat+, BBE+, Kr, Cr, Vr, succicn and isobutyic |
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Bacteroides urealyticum |
Pitting, and dose not grow on BBE, Urase +, Ks, Cs, Vr |
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Prevotella spp |
Anaerobic G-
Black colonies that glow red
Found in human oral cavities
Saccharolytic
Cat- / Kr / Cs / Vr
Causes: Periodontitis, Root canal infections, appendicitis, pneumonia |
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Porphyromonas |
Anaerobic G-
Black colonies with a red glow
Human oral cavity
Cat- / Kr / Cr/ Vs
Causes root canal infections and appendicits |
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Fusobacterium |
Thin, long to large pleomorphic G-
Dry, crummy colonies, hemolyis and blood greening
Cat -/ Nit - / Major butyric acid |
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Fusobacterium mortiferum |
Large G- with a rounded shape
Lip - / SPI -
Glows |
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Fusobacterium necrophorum |
Rounded ends, but less rounded over all
Lip + / SPI +
Glows
Causes Lemierre syndrome: postangial sepsis |
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Fusobacterium nucleatum |
Thin with tapered ends
Lip- / SPI +
Glows yellow |