Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
120 Cards in this Set
- Front
- Back
Non-spore forming gram positive rods |
|
|
Spore Forming gram positive rods |
|
|
General characteristics of Corynebacterium Species |
|
|
What's the most significant Corynebacterium species |
Corynebacterium diphtheriae: difficult to speciate 16s rDNA gene sequencing
|
|
Microscopic colony morphology of Corynebacterium Species |
|
|
Babes-Ernst granules |
|
|
Geographical distribution of C. diphtheriae |
Toxigenic Corynebacterium diphtheriae; worldwide distribution
rare in places where vaccination programs exist |
|
What is the major virulence factor of C. diphtheriae |
Exotoxin: diphtheria toxin, antigenic (uses IgG to block toxin effect)
Only toxin producing bacteria can cause diphtheria
|
|
Toxin production in C. diphtheriae |
Toxin production is inversely proportional to iron availability
Alkaline pH (7.8-8.0)
Oxygen concentration
Iron concentration less amt is needed |
|
Two fragments of toxin |
A-B toxin linked by disulfide bond |
|
A: Active fragment |
|
|
EF2 |
required for protein synthesis |
|
B: Binds to specific cell membrane receptors |
|
|
EF2 ADPR.EF |
inactivated: catalyzes transfer of ADPR to link with them |
|
Other toxigenic strains of Corynebacteria |
C. ulcerans C. pseudotuberculosis
Can produce toxin when lysogenized with Beta-phage containing tox gene |
|
Clinical Infections of Diphtheria: Respiratory |
|
|
Symptoms of Clinical Infections of Diphtheria |
|
|
Systemic effects of Clinical infections of Diphtheria |
|
|
Treatment of Diphtheria |
Administer antitoxin: relieves toxin symptoms, but must use antibiotics to clear the infection
Produced in horses: occasionally a hypersensitivity reaction (10%) |
|
Most cases of Diphtheria in the US |
unimmunized
inadequately immunized persons
Higher in older populations |
|
Nonrespiratory disease of C. diphtheria |
Cutaneous form: more prevalent in the tropics,
Infections occur at the site of minor abrasions,
Less severe than respiratory disease: non-healing ulcers, mostly prevalent in native American populations and in the homeless |
|
Loeffler's serum agar |
Used to demonstrate pleomorphism and metachromatic granules: Babes-Ernst granules |
|
Cystine-tellurite blood agar (CTBA) |
|
|
Laboratory Diagnosis: ID of Corynebacteria |
Confirm id by fermentation reactions Urease Nitrate Toxigenicity testing: must have toxin for disease Elek test: immunodiffusion test, iron poor media PCR for Tox gene |
|
Elek test |
Immunodiffusion test
Iron poor media
(Positive control, toxigenic unknown, negative control, unknown nontoxigenic) |
|
C. jeikeium |
Infections from catheters or prosthetic devices
Sepsis, prosthetic valve endocarditis, meningitis, and peritonitis predominately in immunosuppressed in patients
|
|
Identification of Corynebacterium jeikeium |
|
|
RSU broth |
|
|
Identification of other Corynebacteria, Speciated if: |
|
|
Rothia dentocariosa |
Normal oral flora: Endocarditis
Nitrate positive, non-motile, esculin hydrolysis positive, and urease negative |
|
R. mucilaginosa |
Improtant cause of endocarditis |
|
Undesignated CDC coryneform groups |
|
|
Two pathogenic species of Listeria |
L. monocytogenes- Human pathogen
L. ivanovii- Animal pathogen |
|
Listeria monocytogenes |
Gram-positive, nonsporulating rods
Coccobacillus that often appears like cocci-short rods Widespread in nature, infect animals
Human exposure is limited to: dairy products because it grows at low temp and meats |
|
Listeriosis infection in adults |
|
|
Listeriosis in pregnant women |
Neonatal- early onset from intrauterine transmission results in sepsis; high mortality rate
Late onset manifests as meningitis; low mortality rate |
|
Listeriosis in Immunocompromised |
|
|
Virulence Factors: L. monocytogenes |
|
|
Laboratory Diagnosis: L. monocytogenes Microscopic morphology |
Gram-positive Non-spore-forming Coccobacillary |
|
Culture Characteristics L. monocytogenes |
|
|
Identifying L. monocytogenes |
|
|
Other Identifications of L. monocytogenes |
|
|
Erysipelothrix rhusiopathiae |
|
|
Erysipeloid |
|
|
Endocarditis |
May occur in those who have had valve replacement |
|
Erysipelothrix rhusiopathiae Identification |
Catalase negative Production of H2S on TSI
Culture: CO2 is required Grows on CA |
|
Erysipelothrix rhusiopathiae colony morphology |
Colonies may appear gray or translucent with alpha hemolysis
Pleomorphic, gram-positive thin rods that may form very long filaments-singly, in short chains, or in a V shape |
|
A. haemolyticum infections |
Throat cultures: often indistinguishable from Group A streptococci infection- rash resembling Scarlet fever
Also, soft tissue, endocarditis, sepsis |
|
Arcanobacterium |
All are catalase negative
Narrow zone beta-hemolysis- black dot on agar surface under the colony |
|
Lactobacillus |
|
|
Gardnerella vaginalis |
|
|
Bacterial vaginosis |
|
|
Treatment of Gardnerella vaginalis |
|
|
Laboratory diagnosis of Gardnerella vaginalis |
|
|
Gram Stain Characteristics Gardnerella vagianlis |
|
|
Clue Cells |
Gram stain showing epithelial cell coated with gram variable bacilli
Gram negative curved bacilli and regular GNR
Straight GPR lactobacilli are absent |
|
Nugent Score |
|
|
Gardnerella vaginalis Culture Characteristics |
SBA or chocolate agar: 5%-7% CO2 at 35-37deg
Slow growth, pinpoint colonies at 48 hours |
|
Length of mycolic acid in gram positive rods |
|
|
Acid fast bacteria |
|
|
Modified Acid Fast Stain |
|
|
Modified Acid Fast Primary Stain: |
Stain 3 minutes with carbol fuchsin |
|
Modified Acid Fast Decolorize |
10 seconds with 1% HCl or Sulfuric acid |
|
Modified Acid Fast: Counter Stain |
Stain 30 seconds with methylene blue
|
|
Acid Fast Stain: Primary Stain |
Stain 5 min with carbol fuchsin |
|
Acid Fast Stain: Decolorize |
|
|
Acid Fast Stain: Counter Stain |
Methylene blue 3-4 min |
|
MAF Positive |
|
|
MAF Negative |
|
|
General Characteristics: Nocardia |
|
|
Taxonomy: Nocardia |
|
|
Nocardia: Transmission |
|
|
Older laboratory testing for Nocardia |
|
|
Tropheryma |
Whipple's disease |
|
What is Actinomadura |
is an aerobic actinomycetes |
|
What was Actinomadura once confused with |
fungus |
|
Common cause of Actinomadura |
actinomycotic mycetoma |
|
Clinically relevant species of Actinomadura |
A. madurae and A. pelletieri |
|
What is a characteristic formation of Actinomadura |
granules containing branched filaments |
|
Growth of Actinomadura |
Slow growth on routine mycologic or mycobacteriologic media under aerobic conditions |
|
Chronic infection of Actinomadura |
Chronic infection
|
|
Lowenstein-Jensen medium |
Actinomadura
|
|
Actinomadura madurae v. A. pelletieri |
A. madurae: produce acid from cellobiose
|
|
Streptomyces |
|
|
Gordonia bronchialis |
|
|
Gordonia bronchialis antibiotics |
susceptible to a broad range of antibiotics
|
|
Tsukamurella |
|
|
Rhodococcus |
|
|
Tropheryma whipplei |
|
|
Whipple Disease |
|
|
Bacillus Species |
|
|
Group 1 Bacillus species |
|
|
Group 2 Bacillus species |
|
|
Group 3 Bacillus species |
|
|
Bacillus anthracis |
|
|
Morphology Bacillus anthracis |
|
|
Virulence factor Bacillus anthracis |
Plasmids: Capsule & Exotoxin
|
|
Is there a vaccine for Bacillus anthracis |
Yes, for those with a high risk |
|
Incidence of infection in Bacillus Anthracis |
|
|
Most common infection of anthrax |
Cutaneous:
|
|
Gastrointestinal Anthrax |
|
|
Pulmonary anthrax (Woolsorter's Disease) |
|
|
Microscopic morphology B. anthracis |
|
|
Colonial morphology B. anthracis |
|
|
Suspecting anthrax |
|
|
Treatment of anthrax |
|
|
Bacillus cereus: Food poisoning |
|
|
Infections of B. cereus |
Immunosuppressed hosts:
|
|
Other Bacillus species associated with disease |
Food Poisoning, bacteremia, pneumonia
|
|
What does L. monocytogenes look like? |
Group B strept L. monocytogenes is catalase positive |
|
High risk group for Erysipelothrix rhusiopathiae |
Fish handlers |
|
What is A. hemolyticum indistinguishable from? |
Group A strept; but does not lancefield group type |
|
Main contaminant in urine |
Lactobacillus |
|
Clue cell |
coated in bacteria |
|
In clue cell what can be absent, what does this lead to? |
Lactobacillus; the amount that is present is scored via nugent score 0-4
Gram-variable rods 0-4 Curved gram-variable road 0-2
7-10 consistent with bacterial vaginosis |
|
Nocardia distribution |
ubiquitous in the environment and can be found world wide as saprophytic components
Cutaneous infection
Severe pulmonary or CNS disease in immunocompromised |
|
One way to identify Nocardia |
Paraffin bait test, only Nocardia can break it down as a substance |
|
Gordonia closely realated to |
Rhodococcus |
|
Anthrax |
disease in livestock, Select Agent A |
|
What is needed for B. anthracis virulence |
Both plasmids: capsule and exotoxin |