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Micro Exam 3

Micro exam 3 information

QuestionAnswer
Neisseria gonorrhoeae gram stain morphology Gram-neg diplococci. In males, the precence of intracellular GNDC is highly sensitive and specific for N. gonorrhoeae.
Neisseria gonorrhoeae growth requirements Fastidious (enriched media preferred), requires 3-5% CO2 and increased humidity, CHOC and BAP will grow but not MAC, may take a long time to grow.
Neisseria gonorrhoeae colonial morphology may be pinpoint colonies on BAP.
Enriched plates for Neisseria gonorrhoeae growth Modified Thayer-Martin, Martin-Lewis
Bartonella henselae is the causative agent for? cat scratch fever
Bartonella quintana is the causative agent for? Trench fever, especially in alcoholics and others with macrocytic anemias.
Symptoms of trench fever? persistent or reapsing fever; myalgia, arthralgia, bone pain, splenomegaly
symptoms of cat scratch fever? papule/pustule at primary inoculation site; fever, headache, fatigue, anorexia, malaise, arthralgia; swelling of lymph nodes of head, neck and upper limbs; often self-limiting.
Bartonella species laboratory diagnosis? Not normally cultured due to poor growth on plates. serologic testing by IFA or EIA; PCR can be used to diff between species
Tx of bartonella species? Antibiotic therapy only for invasive infections. Susceptibility testing may be needed, but might not correlate with clinical efficacy
Pasturella multocida habitat normal to oropharynx and GI tract of wild and domestic animals.
Pasturella multocida mode of transmission usually bite/scratch but may be from licking wounds as well.
Pasturella multocida gram stain small GNB, may be coccobacilli
Pasturella multocida biochemicals non-motile, catalase, oxidase, and indole pos; ferment glucose w/ weak acid production on TSI; grow well on BAP and CHOC @ 35-37 C Ambient air/CO2.
Tx of Pasturella multocida? penicillin is the drug of choice.
Capnocytophaga species normal to humans C. gingivalis, C. ochracea, C. sputigena (subgingival surfaces and other areas of human oral cavity
C. canimorsus and C. cynodegmi are normal flroa to what? dogs
Cause of C. gingivalis, C. ochracea, C. sputigena infection transmission? probably patient's endogenous strains
C. canimorsus and C. cynodegmi infection transmission? dog bite/scratch
C. canimorsus and C. cynodegmi gram stain appearance Gram negative fusiform shaped rods that may be curved.
Capnocytophaga species gram stain appearance Gram negative fusiform shaped rods
Motility of capnocytophaga? gliding motility can be observed on wet mount. May swarm similar to proteus, but not as much
BAP and CHOC in CO2 growth of Capnocytophaga species? non-hemolytic with a yellow-orange pigment. doesn't grow in ambient air
C. gingivalis, C. ochracea, C. sputigena treatment produce beta lactamases
C. canimorsus and C. cynodegmi treatment Penicillin is the drug of choice.
Differentiate Neisseria meningitidis and gonorrhoeae. Ferment sugars that match their name (gonorrhoeae = glucose, meningitidis = mannitol and glucose)
Differentiate Neisseria from "look alike" organisms like Moraxella and Acinetobacter. Penicillin disk test will be positive. With sub-inhibitory concentrations, Neisseria will maintain the GNDC appearance and other will have a bizarre morphology.
Disease state of Gonorrhea? Men tend to exhibit more symptoms of urethritis w/ yellow, purulent discharge and painful frequent urination. Women tend to not have as many symptoms but can manifest with vaginal discharge, frequent urination, fever, or abdominal pain.
How is Neisseria gonorrhoeae transmitted and where is it found? Transmitted through sexual contact and can be transmitted to the urethra, cervix, mucous linings of the rectum or oropharyngeal cavity
What can happen if infants are exposed to Neisseria gonorrhoeae during birth and how is it prevented? may lead to blindness if not treated. Prophylactic antibiotics are given to all neonates soon after birth as a state law. The prophylactic antibiotic is an eye drop of erythromycin.
What is Gonococcemia? sepsis caused by n. gonorrhoeae.
What agars will grow Neisseria meningitidis? MTM, BAP, or CHOC will grow in 35-37 C moist 5-7% CO2 environments.
How is Neisseria meningitidis transmitted? transmitted via respiratory ecretions.
Where can neisseria meningitidis be found? respiratory secretions (possibly in carriers) CSF and blood when pathogenic.
Bacterial meningitis affects who and has what symptoms? Most commonly affects 6mo to 2 yoa and 11 to 19yoa individuals especially those in college dorms and military barracks. Symptoms include fever, headache, and stiff neck; characteristic skin rash also may be present.
Syndrome associated with Neisseria meningitidis characterized by fulminant sepsis and DIC? Waterhouse-Friderichsen Syndrome
What makes N. meningitidis virulent? Attaches to epithelial cells that line nasopharynx and move through the cells eventually to the blood stream. In Blood and CSF there is usually a capsule present on the cells that helps it resist phagocytosis and lysis by complement and switches capsules
When must Neisseria species be ID'd to the species level? When isolated from a normally sterile body site
What does Moraxella catarrhalis look like on a gram stain? Gram negative diplococci
What is the colonial morphology of Neisseria meningitidis? Gray, convex, glistening w/ a smooth moist edge; may appear mucoid or gummy with colonies larger than 1 mm. may exhibit alpha hemolysis on BAP.
Colonial morphology of Moraxella catarrhalis? 1 mm, opaque, whitish to grayish pink; raised/dome-shaped; can be pushed on the agar like a hockey puck.
What agars will grow Moraxella catarrhalis? BAP and CHOC but not MAC. Grows best @ 35-37 C and prefers 3-7% CO2. Can also grow at 28 C
Biochemical tests for Moraxella catarrhalis Oxidase, catalase, and nitrate positive; DNAse pos; butyrate esterase pos; do not use sugars for energy.
What disease states are caused by Moraxella catarrhalis? otitis media in children, sinusitis in children and adults, lower resp tract infections in adults. Mostly these infections occur in immunocompromised.
Where can this be isolated from? CSF, blood, eye, urethra, and wounds.
What is done when a potential Bacillus sp. is isolated? most labs only perform enough biochemical tests to rule out Bacillus anthracis. Usually suspected whenever a non-hemolytic catalase pos, aerobic GPB is isolated.
How can Bacillus anthracis be differentiated from other Bacillus species? other Bacillus species are motile and beta-hemolytic
What agars do Bacillus species grow on? BAP and CHOC incubated in ambient air at 35-37 C or in 5% CO2.
What does Bacillus anthracis look like on gram stain? GPB with a boxcar appearance.
What is the colonial morphology of Bacillus anthracis? large, flat, irregular "medusa head", creamy/white or gray colonies w/ a ground glass texture and no hemolysis.
What agar is specific to Bacillus anthracis/ Lecithinase positive
Biochemical tests for Bacillus anthracis MSA shows growth but no fermentation; penicillin susceptibility >15 mm zoi; lecithinase pos; tenacity test (colonies can be pulled into standing peaks.
Cutaneous anthrax cause and symptoms? most common occurring in human cases and least severe. Causes depressed black skin lesions (eschars) at site of entry.
Gastrointestinal anthrax cause and symptoms? usually caused by ingestion of contaminated meat. Affects either oropharyngeal or abdominal area and progresses to toxemia/sepsis.
Pulmonary (wool sorter's disease) anthrax cause and symptoms Most severe and caused by inhalation of spores. Symptoms include malaise, mild fever and non-productive cough leading to resp distress, massive chest edema, cyanosis and death
Reactions of Bacillus to rule out B. anthracis Beta-hemolysis, growth on PEA motile, lecithinase neg, no growth on MSA, fermentation of MSA
What do Corynebacterium grow on? usually on BAP and CHOC in ambient air @ 35-37 C or 5-10% CO2. C. diphtheriae needs to be cultured on cystine tellurite or modified Tinsdale agar.
Habitat of Corynebacterium diphtheriae? not normal flora but may be in nasopharynx in carriers
Mode of transmission in Corynebacterium diphtheriae? person-person via contaminated respiratory droplets, contact w/ exudate from cutaneous lesions, exposure to contaminated objects.
Habitat of Corynebacterium non-diphtheriae? normal flora to various sites, normally pharyngeal or skin
Mode of Transmission of Corynebacterium non-diphtheriae? possible person-person often by transfer of endogenous strain to normally sterile sites.
Corynebacterium diphtheriae appearance on gram stain? resemble palisades, picket fences, chinese letters or V, L and Y shapes.
What media does Corynebacterium diphtheriae grow on? loeffler's medium (not selective enhances growth), Cystine-tellurite blood agar (selective, creates brown halo due to break down of cystine in agar and tellurite inhibits normal flora), Tinsdale medium (selective and differential creates gray-brown halo)
Biochemical reactions for Corynebacterium diphtheriae? catalase pos; non-motile; urease neg; cystinase pos; pyrazinamidase neg; esculin hydrolysis neg; inverse CAMP negative
Respiratory illness with characteristic swollen neck and Sx almost identical to mono. There is an effective vaccine which has caused a reduced number of cases in the US. Diphtheria (caused by Corynebacterium diphtheriae)
habitat of Listeria monocytogenes? widespread in the environment and may colonize the human GI tract.
Mode of transmission of Listeria monocytogenes? ingestion of contaminated food or mother to fetus via GI tract to fetal blood or meninges.
Listeria monocytogenes appearance on gram stain/ short, non-branching, non-spore forming GPB occurring singly or in short chains. In wet mounts, there is a tumbling motility
Motility of Listeria monocytogenes? umbrella shape of haziness in the motility test at room temp.
colonial morphology of Listeria monocytogenes? small, smooth, beta-hemolytic colonies.
Biochemical reactions for Listeria monocytogenes? Motility pos in room temp, nonmotile or reduced in 35-37 C. Catalase, Salt tolerance, and bile esculin positive.
disease associated with listeria monocytogenes? common cause of food-poisoning; may also cause invasive listerosis leading to neonatal meningitis.
What is the habitat of Lactobacillus and Gardnerella species? normal vaginal flora.
Vaginal bacteria that normally does not cause infection;seen as contaminant and may cause bactermia in immunocompromised patients? Lactobacillus species
Causes Bacterial vaginosis, rarely UTI and extremely rarely bacteremia? Gardnerella vaginalis
How to culture Lactobacillus and Gardnerella species grow on BAP and CHOC at 35-37 C at 5-10% CO2. can also use Colistin-Nalidixic Acid to prevent overgrowth of gram negative organisms.
Where other the vagina can lactobacillus be found? part of the normal flora of the oral cavity and GI tract.
Pleomorphic slender GPB; may be long/short; may occur singly, in pairs, or in short chains. Lactobacillus on gram stain
Small, pleomorphic, thin, gram-variable rods/coccobacilli Gardnerella vaginalis on gram stain.
Colonial morphology of Gardnerella vaginalis? pinpoint non-hemolytic colonies on BAP and slightly larger on CHOC
Biochemical results for Gardnerella vaginalis? non-motile, catalase and oxidase neg.
Erysipelothorix rhusiopathiae habitat? Very common in nature but rarely cause human infection. found in pigs and is a zoonosis in humans.
short, non-motile, non-spore forming, GPB, occurring singly or in short/long non-branching filaments that is easily over decolorized. Erysipelothorix rhusiopathiae gram stain.
Colonial morphology of Erysipelothrix rhusiopathiae? Facultative anaerobe that produces pinpoint colonies on BAP at 24 hr incubation. Also grows on CHOC and CNA. At 48 hrs incubation, alpha hemolysis may be seen under the colonies.
Biochemical results for Erysipelothrix rhusiopathiae? Catalase, oxidase, urease neg; produces H2S on TSI; Pipe cleaner growth in motility incubated at 22 C.
Aerotolerant actinomyces habitat normal flora to various body sites especially the mouth.
Aerotolerant actinomyces gram stain non-spore forming, non-acid fast, pleomorphic GPB
ID of Aerotolerant Actinomyces ID to genus with Gram stain morphology, catalase neg, and atmospheric presence.
Gram stain appearance of aerobic Actinomycetes? thin, breaded branching GPB
Habitat of aerobic Actinomycetes? exist in environment soil, water, and decaying plant matter.
Transmission of Nocardia? inhalation or direct skin inoculation
Colonial morphology of Nocardia? may be smooth and raised or chalky, crumbly, cottony; white/pink/orange/tan, spider colonies. slow growers and may be obscured by overgrowth of normal flora
Biochemical results for Nocardia? catalase pos; paritally acid-fast; branching GPB w/ aerial mycelium; lysozyme positive (grows in the presence of lysozyme); Molecular testing to ID species
Where can Streptomyces be isolated from? subcutaneous wound infections, sputum, blood, and CSF
Colonial morphology of Streptomyces may be smooth and raised or chalky, crumbly, cottony; white/pink/orange/tan, spider colonies. slow growers and may be obscured by overgrowth of normal flora. May appear glabrous or waxy and heaped.
differential reactions for Streptomyces? Non-acid fast, lysozyme negative, nitrate negative.
habitat of Vibrio cholerae primarily in GI tract of infected individuals, can e dormant in brackish/salt water.
Transmission of Vibrio cholerae? fecal-oral via ingestion of contaminated water or contaminated shellfish or other seafood.
Habitat of Vibrio parahaemolyticus and Vibrio vulnificus? Brackish/saltwater
Transmission of Vibrio parahaemolyticus and Vibrio vulnificus? ingestion of contaminated water or seafood
Habitat of Aeromonas hydrophilia? Fresh or brackish water primarily, occasionally marine water and may transiently colonize GI tract
Transmission of Aeromonas hydrophilia? Ingestion of contaminated food/water; exposure of disrupted skin or mucosal surfaces
Habitat of Chromobacterium violaceum? Environmental, soil and water of tropical and subtropical regions
transmission of Chromobacterium violaceum? Exposure of disrupted skin to contaminated soil/water
Habitat of Plesiomonas shigelloides? Fresh/brackish water; normal flora in a variety of animals
Transmission of Plesiomonas shigelloides? Consumption of undercooked contaminated shellfish; exposure of skin or ingestion of contaminated water.
How do you differentiate Vibrio cholerae from V. parahaemolyticus and V. vulnificus? Thiosulfate Citrate Bile Salts Sucrose agar will be yellow for V. cholerae and green for V. parahaemolyticus and V. vulnificus. On BAP cholerae may be beta hemolytic while the others are not.
how do you use MAC to differentiate Vibrio vulnificus from V. cholerae and V. parahaemolyticus? V. cholerae and V. parahaemolyticus are NLF, V. vulnificus may ferment lactose or may be delayed in fermentation.
What is the colonial morphology of Vibrio species? Medium-large, smooth, opaque, irridescent with a greenish hue
Created by: wulfmannwarrior