Bacteria Flashcards
(74 cards)
1
Q
What are the 6 major gram positive bacteria and their general characteristics
A
Staphylococcus
- Cocci
- Catalase +
Steptococus/Enterococus
- Cocci
- Catalase -
Bacillus
- Bacilli
- Spore forming
- Aerobic
Clostridium
- Bacilli
- Spore forming
- anerobic
Corynebacterium
- Non-spore forming
- Club shaped
Listeria
- Bacilli
- Non-spore forming
- Motile at 25 C
2
Q
Are catalase or coagulase present in the following gram positive bacteria:
Staphylococcus Aureus
Staphylococcus epidermis
Staphylococcus saprophyticus
A
Staphylococcus Aureus: catalase +, coagulase +
Staphylococcus epidermidis: catalase +, coagulase -
Staphylococcus saprophyticus: catalase +, coagulase -
3
Q
Staphylococcus Aureus
Major disease manifestations
A
Pneumonia
Superifical skin & underlying soft tissue infections
- Folliculitis
- Impetigo
- Cellulitis
- Abscess
Endocarditis (acute, necrotizing)
- Classic case is IV drug abuser using dirty needles
4
Q
Staphylococcus Aureus
Role of key Toxins
A
Gastroenteritis (food poisoning)
- preformed enterotoxin (quick onset)
- Nausea, vomiting, diarrhea, abdominal pain
Scalded Skin Syndrome
- Exfoliative toxin A & B
- Peeling of skin
Toxic Shock Syndrome
- Due to TSST-1 toxin (superantigen)
- Long term superabsorbant tampon use
- Diffuse Rash (involves palms and soles)
- Shock, hypotension, death
5
Q
What organism is known for infecting prosthetic devices (heart valves, hardware, cathethers, shunts) and uses a biofilm as it’s virulence factor?
What is the disease manifestation of this organism
A
Staphylococcus epidermidis
Subacute endocarditis - low grade fever
6
Q
What organism is the common cause of community acquired UTIs
A
Staphylococcus saprophyticus
7
Q
Categorize the alpha, beta and gamma streptococcus
A
Alpha (partial hemolysis)
- S. pneumoniae
- Viridans Group
Beta (complete hemolysis)
- S. pyrogenes
- S. agalactiae
Gamma (no hemolysis)
- Enterococci group
- S. bovis
8
Q
Streptococcus pyogens (Group A)
- Disease manifestation
- Virulence factor
A
- Disease Manifestations
- Streptococcal pharyngitis (strep throat): white exudate of tonsils/pharynx
- Scarlet fever
- Erysipelas: sunburn type appearance (face), warm to touch, peak age 60-80
- necrotizing facitis: rapidly progressive, purplish discoloration
- Impetigo: golden crusted rash see in children
- Cellulitis: Non-necrotizing on subcutaneous tissue, swollen, erythematous, warm
- Rheumatic fever
- Post-Streptococcal Glomerulonephritits
- M protein = inhibits activation of complement
9
Q
What causes Scarlet fever & what are the clinical manifestations
A
- Due to pyrogenic exotoxin of Streptococcus pyogenes
- Fever, rough “sandpaper” like rash on trunk and neck. Stawberry tongue. School age children
10
Q
Rheumatic fever
- Disease manifestation
- Pathogenesis
- Diagnostic test
A
- JONES: Fever, migratory polyarthritis, large joints, subcutaneous nodules, erythema marginatum (macular rash), heart involment (pericarditis, mitral valvulitis), sydenham chorea (hopping, halthing gait, grimacing)
- Disorder that occurs following a group A S. pyogenes pharyngeal infection caused by antibodies created to the M streptococcal antigen
- Detection of antibodies to streptolysin O and DNase B
* Said will definitly expect us to recognize a classic case presentation of this disease*
11
Q
Post-streptococcal Glomerulonephritits
- Disease manifestation
- Pathogenesis
- Diagnostic test
A
- Usually in children, edema, hypertension, hematuria, proteinuria
- Immune mediated rxn to Group A streptococcus, S. pyogenes following pharyngitis or skin infection
- Detection of antibodies to streptolysin O and DNase B
12
Q
Streptococcus agalactiae (Group B)
Disease manifestation
A
A galacta baby
Neonatal meningitis, pneumonia, sepsis
“B” = Babies, Group B Strep & Beta hemolytic
13
Q
Streptococcus pneumoniae
- Identifying characteristics
- Clinical manifestations
A
- Characteristics
- Encapsulated alpha hemolytic
- Positive quellung reaction (swollen capsule)
- Optochin sensitive (antibiotic)
- # 1 cause of MOPS (meningitis, otitis media, pneumonia, sinusitis)
14
Q
What is the most common cause of community aquired pneumonia & what is the manifestation of pneumonia
A
Streptococcus pneumoniae
Lobar consolidation on chest x-ray w/ high fever, chills, cough, SOB frequently seen in elderly (older than 65)
15
Q
What is the #1 cause of meningitis in young children and what is the classic presentation
A
Streptococcus pneumoniae
Classic triad:
- high fever >100.4 F
- Nichal rigidity
- Abnormal mental status change
16
Q
What is the most common cause and basic presentation of otitis media in children
A
- Bacterial causes
- Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
- Ear pain, tugging/pulling at ear
17
Q
- What role does the spleen have on encapsulated bacteria
- What are the 3 main disease causing encapsulated bacteria
A
- Encapsulated bacteria are opsonized and cleared by the spleen
- Streptococcus pneumoniae, Haemophilus influenza (type B), Neisseria meningitis
18
Q
Viridans Group Streptococci
Major disease manifestations
A
- Dental carries
- Subacute bacterial endocarditis (low grade fever, fatigue). Same in HACEK organisms
- Typical clinical history: Endocarditis following dental procedures that allows organisms to spread hematogenously to heart valves*
19
Q
Differentiate Enterococci & Group D non-Enterococci
A
Enterococci (Group D)
- Cause nosocomial infections
- grow on bile and 6.5% salt
Non-Enterococci Group D
- Strongly associated with colon cancer (Streptococci bovis)
- Grown on bile but not salt
20
Q
Bacillus cereus
- Characteristic
- Major disease manifestation
A
- Gram positive, spore forming rod that is extremely resistant to heat. Spores germinate, bacteria create toxins.
- Heat stable toxin: emetic disease (nausea/vomiting, abdominal pain)
Heat labile toxin: Watery diarrhea
21
Q
Bacillus anthracis
- Characteristics
- Risk factors for acquiring
- Disease manifestation
A
- Gram positive, encapsulated, spore forming rod
- Spore found on herbivore animals products (hides) - sheep
- Manifestations
- Cutaneous anthrax: malignant pustile
- Inhalation anthrax: pulmonary spores —> mediastinal hemorrhage -> death (agent of bioterrorism)
22
Q
Clostridium difficile
- Predisposing factor
- Virulence
- Pathologic findings
A
- causative organisms of antibiotic associated colitis (clindamycin, penicillins)
- Virulence factors
- Toxin A: Increases inflammation, increase fluid secretion (diarrhea)
- Toxin B: Cytotoxic to colonic epithelial cells
- Pseudomembranous colitis
23
Q
Clostridium botulinum
- Mechanism of action
- Risk factors for disease
- Disease manifestation
A
- Neurotoxin in bacteria inhibits release of acetylcholine at the NMJ
- Canned food, honey
- Bilateral cranial neuropathies, symmetric descending muscle weakness –> respiratory paralysis, death.
Infantile botulism: Spore consumption from honey –> constipation–>difficulty swallowing, muscle weakness
24
Q
Clostridium tetani
- Mechanism of action
- Risk factors for disease
- Disease manifestation
A
- Neurotoxin inactivates glycine and GABA leading to sustained contraction of motor neurons
- Deep puncture wounds
- Severe muscle spasms, autonomic instability, Opsisthotonos (arching of headm neck &spine/body), clenched jaw
25
**Clostridium perfringens**
1. Risk factors for disease
2. Disease manifestation
1. Deep wounds/trauma
2. Manifestation
* hemolysis & hemorrhage
* Cellulitis/wound infections that can progress to myonecrosis **(gas gangrene, CO2 production, crepitus)**, dark purple to black skin discoloration
26
**Corynebacterium (club shaped)**
1. Virulence factor
2. Clinical presentation
3. What potentiates its systemic absorption
1. AB exotoxin
2. Pharyngitis w/ pseudomembrane formation
3. Scraping causes systemic absorption of toxin which can lead to
* **Myocarditis:** Dysrhythmias, AV conduction block
* **Neural involvement**
27
**Rhodococcus equi (club shaped)**
Clinical presentation
Cause pulmonary disease in immunocompromised and can cause abscess cavities with prominent air fluid levels on chest x ray
28
**Listeria Monocytogenes**
1. Optimal growth conditions
2. Risk factors
3. Disease manifestation
1. Grows at cooler temperatures
2. Dairy products, deli meats, sprouts (pregnant women told to avoid)
3. Manifestations
* Fetus/neonates: granulomatous infantiseptica & neonatal meningitis
* Pregnant women: sepsis
* Older adults & immunocompromised: meningitis
29
List the gram (-) diplococci
Neisseria meningitis
Neisseria gonorrhea
Moraxella catarrhalis
30
**Neisseria meningitis**
1. Characteristics
2. Susceptible populations
3. Clinical presentation
1. Grows on chocolate agar (Thayer Martin agar)
2. Neonates, 1/2 to 2 yrs, military recruits, college students (dorms), asplenia/hyposplenia
3. Clinical presentation
* Meningitis (fever, stiff neck, nausea/vomiting, rash)
* Meningococcemia: meningitis + septicemia
* **Waterhouse-Friderichsen syndrome:** bilateral adrenal hemorrhage with insufficiency, severe hypotension, disseminated intravascular thrmbosis, death
31
**Neisseria gonorrhea**
1. Agar growth conditions
2. Clinical presentation in men, women & neonates
1. Intracellular gram negative diplococci that grows on Thayer-Martin chocolate agar
2. Clinical presentatin
* **Men:** Urethritis, acute epididymitis (posterior testicular pain, swelling)
* **Women:** Urethritis, cervitis (itiching,discharge), pelvic inflammatory disease **(can cause sterility and present with pelvic/abdominal pain)**
* **Infants:** opthalmia neonatorum = neonatal conjunctivitis
32
**Moraxella catarrhalis**
1. Features
2. Disease presentation
1. Gram negative diplococcis grown on blood and chocolate agar
2. Third most common cause of otitis media in children
33
**Escherichia coli**
1. Principal properties
2. Diseases
1. Gram negative rod, lactose fermenter, normal flora of GI tract
2. Diarrhea, meningitis, UTI, pneumonia
* common cause of neonatal meningitis and most common cause of UTI*
34
**Enterotoxigenic E. coli (ETEC)**
1. Risk factor
2. Key toxins
3. Clinical presentations
1. Fecally contaminated food or water
2. Heat labile (LT) and heat stable (ST) toxins
3. Watery diarrhea
35
**Enteroinvasive E. coli (EIEC)**
Clinical presentations
Invasive plasmid leading to bloody diarrhea
36
Enterohemorrhagic E. coli (EHEC)
1. Risk factor
2. Key toxins
3. Clinical presentations
1. Foods
2. Shiga-like toxin
3. **Hemolytic uremic syndrome (HUS)**
* Caused by **EHEC E. coli 0157**
* Anemia, thrombocytopenia, renal damage/failure (uremia)
37
**Shigella**
1. Disease manifestations
2. Pathogenesis
Gram negative rod, always pathogenic
## Footnote
1. High fever with bloody diarrhea
2. S. dysenteriae produced Shiga toxin resulting in cell death
38
**Typhoid fever**
1. cause
2. clinical fidings
1. Salmonella typhi
2. Clinical findings
* "stepwise fever"
* colicky RUQ abdominal pain
* Delirium "typhoid encephalopathy"
* "rose spots" on abdomen
39
**Yersinia enterocolitica**
1. Presentation
2. Risk factors
Gram negative rod
## Footnote
1. Fever, abdominal pain, diarrhea, RLQ pain = pseudoappendicitis
2. Milk products
40
**Proteus mirabilis**
Unique features
Swarming motility
urease positive
common cause of UTI especially in nosocomial settings
41
**Klebsiella pneumoniae**
1. Types of patients affected
2. Disease manifestation
Gram negative rod, encapsulated
## Footnote
1. Alocholics and hospitalized patients
2. Pneumonia (necrotizing, cavitary) w/ red currant jelly sputum
42
**Pseudomonas aeruginosa**
1. Characteristic
2. Patients commonly affected
3. Major types of infections causes
1. Gram negative rod, produces green-blue pigment and had distinct grape like scent
2. Patients
* Cystic fibrosis (CF)
* Burn victims
* debilitated, typically hospitalized patients
3. Infections
* Pulmonary infections (mild bronchitis to pneumonia)
* Primary skin/wound infections (burn wounds, otitis externa, hot tub folliculitis)
43
**Bacteroides fragilis**
1. Features
2. Disease manifestations & Predisposing factors to infection
1. Gram negative bacillus, obligate anaerobe
2. Manifestation/predisposing
* Abscess after traumatic bowel injury
* Abscess after ischemic bowel perforation
* Deep abscess (deep surgical sites)
44
**Vibrio cholerae**
1. Clinical manifestation
2. Predisposing factors
1. Profuse watery diarrhea leading to dehydration
2. Transmitted from brackish and marine water. Cholera toxin activates cAMP causing an osmotic pull of water into bowel lumen.
45
**Vibrio vulnificus**
1. Predisposing factors
2. Clinical manifestations
1. Consumption of raw seafood
2. **Consumption:** Severe diarrhea, septicemia (sudden fever, chills, hypotension, nausea/vomiting)
**Direct handling:** progressive wound infection
46
**Vibrio parahaemolyticus**
1. Predisposing factors
2. Clinical manifestations
1. Consumption of raw seafood
2. Watery diarrhea, nausea/vomiting (most common cause of food poisoning in Japan)
47
**Campylobacter jejuni**
1. Predisposing factor
2. Clinical findings
3. Notable association
1. Uncooked meat (chicken), unpasteurized milk
2. Invades small bowel & colon causing fever, diarrhea (+/- blood), severe abdominal pain, can mimic acute appendicitis
3. **Guillain-Barre syndrome**: an immune mediated neuropathy causing ascending flaccid paralysis
48
**Reiter's Syndrom/Reactive arthritis**
1. Trigger
2. clinical manifestations
1. Associated with HLA-B27. Can be triggered by many of the enteric bacteria
2. Classic triad: conjunctivitis, urethritis, arthritis
49
**Helicobater pylori**
1. Clinical manifestations
2. Long term risk
3. Diagnosis
1. Chronic gastritis (nausea/vomiting), gastric and duodenal ulcers (pain)
2. Gastric B-cell lymphoma (MALT), Gastric adenocarcinoma
3. Positive rapid urease test
50
**Bordetella pertussis**
1. What disease does it cause
2. Associated toxin
1. Whooping cough: hacking cough followed by a high pitched inspiratory whoop
2. Pertussis toxin (increases cAMP lymphocytosis)
51
**Legionella pneumophila**
1. Risk factors
2. What disease does it cause
1. Found in water system (cooling towers, condensers, showers, tubs)
2. Disease
* **Pontiac fever:** self limited febrile illness (2-5 days): fever, chills, myalgia, malaise, headache)
* **Legionnaires' disease:** more severe multilobular pneumonia with abscess
52
**Haemophilus influenzae**
1. Disease manifestation
2. Growth characteristics
3. Importance of vaccination
1. Manifestation
* Encapsulates
* Early childhood meningitis
* acute epiglottitis
* wheezing, drooling
* Unencapsulated
* Otitis media
2. Require hemin and NAD (X and V factors) for growth, both found in blood.
3. Hib vaccination
53
**Haemophlius ducreyi "chancroid"**
Typical presentation
**Painful** genital ulcer "chancroid" that can cause unilateral pus forming inguinal lymphadenopathy
sexually transmitted
**LOOK AT AND KNOW SLIDE 107/ PPT 91**
54
**Gardnerella vaginalis**
Basic presentation
Cause of bacterial vaginitis detected on Pap smear as "clue cell". Replaces normal vaginal flora resulting in malodorous "fishy smelling" discharge, prutitus and dysuria
55
**Yersinia pestis**
1. Disease manifestation
2. Transmission
1. Bubonic plague (hemorrhage under skin) & pneumonic plaque
2. Reservoir (prarier dogs), vector (fleas)
56
**Francisella tularensis**
1. Disease manifestation
2. Transmission
1. Similar to bubonic plague except presents with skin ulcers
2. Rabbits or via tyick/deerfly bite
57
**Brucella species**
1. Describe infection
2. Risk factor
1. Fever, night sweats, **undulant fever (rising and falling)**, anemia, leukopnia
2. Domesticated animal products, milk, meat, placenta
58
**Pasteurella multocida**
1. Describe infection
2. Risk factor
1. Localized wound infection (cellulitis)
2. Bite or scratch from cats and dogs
59
**Chlamydia trachomatis**
Clinical manifestations
**Non-goococcal urethritis**
* Dysuria, discharge in men
* Dysuria, increased frquency in women
**Epididymitis (men)**
**Pelovic inflammatory disease (women)**
* Infertility
**Trachoma (pediatricts)**
* Chronic eye infection
**Neonatal inclusion conjunctivitis**
**Lymphogranuloma venereum**
* Caued by L1-L3. Tender suppurative inguinal lymphadenitis which can ulcerate
60
**Chlamydia pneumoniaq & Chlamydia psittaci**
1. Presentation
2. Major transmission risk
1. Atypical pneumonia (dry cough, low grade fever, with patchy interstitial inflammatory changes)
2. Chlamydia psittaci - **bird** exposure
61
**Rickettsia species**
1. General clinical presentation
2. Vector & reservoir of Rickettsia rickettsii
1. Fever, rash, thrombocytopenia
2. Ticks/Dogs, rabbits, wild rodents
62
**Rocky Mountain spotted fever**
1. Presentation
2. Geographic distribution
3. Causative organism
1. Fever, centripetal rash including palms and soles
2. Central, southeast U.S.
3. Rickettsia rickettsii
63
**Ehrlichia chaffeensis**
1. Characteristics
2. Clinical manifestation
1. Intracellular tick born illness
2. Similar to RMSF except **no rash** transmitted by ticks in **Southeast and Central United States**
64
**Coxiella burnetti (Q fever)**
1. Clinical manifestations
2. Risk factors
1. Fever, headache, atypical pneumonia
2. Found in cattle, sheep, goats. Airborne transmission from spore contaminated hide and birth products
65
**Treponema pallidum**
Time course & key clinical features
**Primary**
* 3-6 weeks
* painless chancre
**Secondary**
* 6 weeks
* Condyloma lata, macular red rah (including palms and soles)
**Tertiary syphilis**
* 6-40 yrs
* Gummatous lesions
* Thoracic aortic aneurysm
* Neurosyphilis (meningitis, tabes dorsalis)
* Argyll Robinson pupils
66
**Treponema pallidum**
Congenital syphilis key features
**Congenital syphilis**
* 2 years after birth
* mucous membrane involvement (rhinitis) "snuffles"
* Manifestations of sencondary syphilis (rash-including palms and soles)
**Late congenital syphilis**
* \>2 yeard after birth
* tertiary syphilis
* neurosyphilis
* bone and teeth involvement
67
**Treponema pallidum**
Syphilis Screening and Diagnostic test
**Screening test**
* VDRL (venereal disease research laboratory)
* RPR (Rapid plasma reagin)
**Diagnostic tests**
* FTA-ABS
68
**Borrelia burgdorferi**
1. Disease
2. Vector, reservoir, geographic location
1. Lyme disease (#1 tick-borne illness)
2. Ixodes tick (blacklegged ticks), deer/mice, Northeast U.S., Upper Midwest
69
**Borrelia burgdorferi**
Lyme disease manifestation
**Early localized disease**
* erythema migrans (at bite site)
**Early disseminated disease**
* nervous system (Bell's palsy), heart, joints
**Late disease**
* chronic arthritis
* encephalopathy
70
**Mycobacterium tuberculosis**
Differentiate primary and secondary Tb
**Primary tuberculosis (Tb)**
* Aerosolized transmission
* begins in the lungs
* immunocompromised elderly & young
* Fever, chest pain, hilar lymphadenopathy
* histologic findings: necrotizing granulomas
**Secondary tuberculosis**
* Appears months to years
* low grade fever, night sweats & hemoptysis
* Apex UL
* Can disseminate casuing miliary tuberculosis (innumerable lesions throughout organs)
* Any organ can be involved: (If verterbal involvement = Pott's disease)
71
What is the screening test for tuberculosis
Tuberculin skin test & interferon-gamma release assays
72
Differentiate between tuberculoid leprosy and lepromatus leprosy
Primary reservoir in US
**Tuberculoid leprosy**
* Strong cell mediated response (Th1, IFN-gamma)
* Localized skin lesions
* Granulomatous inflammation
* Unilateral skin/ nerve; loss of nerve sensation
**Lepromatous leprosy**
* No/minimal cell mediated response
* disseminated disease: skin lesion cover the body; involvement of organs
**Rservoir: armadillos in southern U.S.**
73
**Mycobacterium pneumoniae**
1. Clinical presentation
2. Key associations
1. **Presentation**
* Walking pneumonia - mild, self limited bronchitis and penumonia
* very common cause of atypical penumonia
2. **Associations**
* Nonspecific cold agglutinins diagnostic test
* Associated with erythema multiforme: multiple target lesions
74
What organisms with no cell wall are a cause of urethritis
Mycoplasma genitalium
Ureaplasma urealyticum
