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82 Cards in this Set
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- Back
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Symptoms of endocarditis (4)
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Hemorrhagic lesions in nailbeds, eyes or extremities
Fever and fatigue following recent dental manipulation or poor dentition Fever and fatigue following GI or GU manipulation Vague symptoms such as depression, low back pain, fatigue, and weight loss |
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Cause of chronic endocarditis after dental procedures
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viridans strep
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If the patient had fever and fatigue following GI or GU manipulation, which organism might you consider as an etiology of infective endocarditis?
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E. coli
GI and GU tract is rich in E coli |
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2 broad categories of vascular infections
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1) Intravascular - within CV system (minority)
2) Extravascular - bacteria enter the bloodstream through the lymphatics from another site of infection. |
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4 causes of intravascular infections
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INFECTIVE ENDOCARDITIS
MYCOTIC ANEURYSMS – infection in arterial walls THROMBOPHLEBITIS – infection in veins INTRAVENOUS CATHETER – ASSOCIATED BACTEREMIA |
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Localized infection which is likely to give rise to bacteremia
Fever of unknown origin Multisystem disease Cardiac manifestations suggesting endocarditis Specific infections associated with a bacteremia phase Rapid, downhill course of unknown etiology What do these have in common? |
Indications for drawing a blood culture
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What happens During early stages of specific infections?
Typhoid fever Brucellosis Leptospirosis |
Continuous bacteremia
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What happens During the course of these diseases?
Meningitis Pneumonia Pyogenic arthritis Osteomyelitis |
intermittent bacteremia
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Group A Strep/Strep pyogenes causes what diseases?
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1) Strep throat
2) Scarlet fever 3) Rheumatic fever (delayed antibody mediated) 4) Post-strep glomerulonephritis (delayed antibody mediated) 5) Strep skin infections |
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Virulence factor for Group A Strep/Strep Pyogenes
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M protein.
Also Streptolysin O, S, and pyrogenic/erythrogenic exotoxin (scarlet fever); streptokinase |
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Enterococci (faecium and faecalis) and Group D Strep are ______ hemolytic
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alpha
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What diseases does Bartonella spp. cause? What are symptoms?
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Cat-scratch disease(henselae):
Can cause bacteremia, endocarditis, bacillary angiomatosis in AIDS patients Trench Fever (quintana): 5 day interval between febrile episodes. High fevers, aches and pains. Louse-dorm. |
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Bartonella is gram ___
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negative
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Characteristics of Coxiella burnetti
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-small obligate intracellular
-Gram negative -extremely low infectious dose needed to cause disease -acute stage that presents with headaches, chills, and respiratory symptoms, and an insidious chronic stage. -atypical pneumonia -NO RASH |
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Characteristics of Coxiella burnetti infection, Q fever
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-acute stage that presents with headaches, chills, and respiratory symptoms, and an insidious chronic stage.
-atypical pneumonia -NO RASH |
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responsible for diphtheria
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Corynebacterium diphtheriae
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What are the virulence factors/toxins of Corynebacterium diphtheriae?
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Must by lysogenized by a phage to gain them.
A subunit: inactivates EF which blocks protein synthesis. B subunit: provides entry into cardiac and neural tissue. "Anti-human antibiotic" |
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Which E coli causes cholera-like disease, has Heat Labile and Heat Stabile toxins? (LT and ST)?
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EnteroTOXIgenic E Coli (ETEC)
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which E coli has Shiga-like toxin that inhibits protein synthesis, resulting in cell death? Results in bloody diarrhea and severe cramps. Causes hemolytic uremic syndrome.
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Enterohemorrhoragic E coli (EHEC)
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Which E coli causes the same disease as that caused by Shigella, giving bacteria ability to invade epithelial cells?
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Enteroinvasive E coli (EIEC)
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Which E coli produes diarrhea that is bloody with WBCs?
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Enteroinvasive E coli (EIEC) - just like Shigellosis!
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Which E coli can cause fever due to the invasion of epithelial cells?
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EIEC
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3 types of bacteremias
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1) Continuous
2) Transient 3) Intermittent |
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localized, irreversible arterial dilatation due to destruction of the vessel wall by infection. It is a serious clinical condition with significant morbidity and mortality. Can develop either when a new aneurysm is produced by infection of the arterial wall or when a preexisting aneurysm becomes secondarily infected.
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mycotic aneurysm
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Chewing, teeth brushing causes what type of bacteremia?
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Transient
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Septic shock; Bacterial endocarditis and other intravascular infections
associated with what type of bacteremia? |
Continuous
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causative agent of typhoid fever
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salmonella typhi
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Symptoms of typhoid
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1-3 weeks after exposure, fever, headache, abdominal pain develops, often mimicking appendicitis. May develop diarrhea and spots on abdomen.
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Treatment of Salmonella typhi
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Quinolones, 3rd gen cephalosporins
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Salmonella typhi is gram _____ and (does, does not) ferment lactose
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Negative; does NOT ferment lactose
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E coli is gram ____ and (does, does not) ferment lactose
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Negative; DOES ferment lactose
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Klebsiella is gram ____ and (does, does not) ferment lactose
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Negative; DOES ferment lactose
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Undrained abscesses
During the course of some diseases Meningitis Pneumonia Pyogenic arthritis Osteomyelitis What kind of bacteremia? |
Intermittent
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What's in a blood culture set?
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Both anaerobic and aerobic bottle
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How many blood culture sets are needed?
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3
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The one most important thing to keep in mind when drawing blood cultures is:
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Blood volume. Need about 20-30 mL
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Cryptococcosis: major manifestation and symptoms
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subacute to chronic meningoencephalitis. Common in AIDS.
Symptoms are HA, nausea, staggering gait, CN deficits. |
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Cryptococcosis: treatment
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Ampho B and flucytosine followed by fluconazole
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Shigellosis: what populations affected?
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MSM, preschool children, nursing home
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Shigellosis: symptoms
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Fever, then abdominal pain, diarrhea that has pus and blood.
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Why do Cholera and ETEC not cause fever?
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They don't invade epithelial cells
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4 disease states caused by Salmonella in humans?
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1) typhoid fever
2) carrier state 3) sepsis 4) gastroenteritis/diarrhea |
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Symptoms of typhus (Rickettsia)
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High fever
Intense generalized headache Diffuse myalgias Rash, eschar, and other signs and symptoms may also be present. |
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How to dx typhoid fever?
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1) Stool culture only effective in 33%
2) Blood culture only effective in 50% 3) BONE MARROW culture effective in 90% So, if blood and stool don't show it up, but you're suspicious, try bone marrow. |
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Typhoid patients who work in food: when can they return?
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Three negative stool cultures over the course of at least 5-7 days
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What patients are particularly prone to Salmonella osteomyelitis?
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Sickle cell anemia
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Diarrheal bacterial pathogens routinely searched for at MCV
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Salmonella
Shigella Campylobacter Aeromonas and Plesiomonas Shiga toxin- producing E. coli |
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T/F Campylobacter will grow on blood agar
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F
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Yersinia enterocolitica: symptoms of infection
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Fever, diarrhea, abdominal pain, most severe in RLQ (mimics appendicitis)
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Yersinia enterocolitica: pathogenesis
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possesses virulence factors allowing binding to intestinal wall and systemic invasion into regional lymph nodes
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T/F Campylobacter will grow on MacConkey agar
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F
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T/F Yersinia enterocolitica,
Vibrio spp. grow on MacConkey Agar. |
Sort of true. There will be growth but it won't be optimal.
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How to diagnose C jejuni?
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To successfully recover from stool specimens, requires ALL of the following:
Selective media – enriched, antibiotics Special atmosphere Special temperature - 42°C (not 37°C) |
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Most common causes of diarrhea worldwide
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C jejuni, ETEC, Rotavirus
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T/F VCU Tests ALL stools submitted for routine culture for detection of bacterial pathogens for STEC (Shigatoxigenic group of Escherichia coli )
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T
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Legionella pneumoniae : symptoms
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nausea, vomiting and diarrhea followed by chills and fever and a non-productive cough.
A necrotizing, multifocal pneumonia. Organisms found within macrophages. Inflammatory exudate. |
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How to culture Legionella?
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Buffered charcoal yeast extract (BCYE)agar.
(supplemented with L-cysteine AND a source of ferric ions.) Even then the sensitivity isn't great. |
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Why does the urine antigen test for Legionella NOT rule it out if negative?
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Detects Legionella pneumophila serogroup 1 only
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What viruses cause serious respiratory problems in YOUNG adults?
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Influenza A, adenovirus and hantavirus
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Symptoms of influenza A and B in children
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bronchiolitis, croup, otitis media
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most commonly cause illness of the respiratory system; however, depending on the infecting serotype, they may also cause various other illnesses, such as gastroenteritis, conjunctivitis, cystitis, and rash illness.
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adenovirus
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Symptoms of RSV in infants?
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bronchiolitis, pneumonia and croup (in children – upper respiratory disease)
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How do parainfluenza viral infections differ in adults vs children?
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Adults: rarely pneumonia, primarily upper respiratory disease
Children: upper respiratory disease including croup and bronchiolitis; pneumonia |
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Cause of "summer flu"
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Enteroviruses
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What specimens are recommended to help diagnose the majority of viral respiratory disease in immunocompetent subjects?
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Upper respiratory specimens:
Nasal washes Nasal aspirates Nasopharyngeal swabs The more serious the disease, the more invasive the specimen. |
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T/F Rapid antigen assays for RSV, influenza A, and influenza B
are very useful clinically. |
F. They have very poor sensitivity and specificity.
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R-Mix shell vial method
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Method used to detect viruses. Relatively quick but still takes 1-2 days.
It's a mix of 2 cell lines used for routine isolation and detection of Flu A and B, parainfluenza, RSV, adenovirus. |
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Prodesse ProFlu+ Assay
: What happens? |
1)Nucleic acid extraction
2) Reverse transcription (all 3 are RNA viruses) 3) Real time PCR |
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T/F Overall sensitivity of an acid-fast smear is poor in detecting TB
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T
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How many consecutive sputum smears are needed to rule out TB?
When should samples be collected? |
Need 3.
Should be collected early morning |
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If sputum specimens non-diagnostic, what do?
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obtain BAL (broncheoalveolar lavage)
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Two major causes of pharyngitis, especially patients between the ages of 5 and 15 who seek medical attention:
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1) Group A Strep
2) Viruses (adenovirus, rhinovirus, coronavirus and RSV) |
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Two ways to detect Group A Strep
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1) Culture: min 24-48 hours.
2) Rapid antigen: reasonably high sensitivity and specificity, but still not perfect. |
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What should happen with a negative Group A Strep test that is symptomatic?
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Should be cultured
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What drug to prescribe for Group A Strep?
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Penicillin. No resistance reported.
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What is first-void urine used to detect?
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Used to detect sexually transmitted agents, Neisseria gonorrhoae and Chlamydia trachomatis, using DNA amplification methods
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If the urine was transported to the laboratory at room temperature, what is the maximum acceptable transport time?
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30minutes. This is because urine is a great culture media and other things would start to grow.
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If the urine was transported to the laboratory at 4ºC, what is the maximum acceptable transport time?
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24 hr
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Distinction between number of organisms for
A) Cystitis B) Pyelonephritis |
A) >10<sup>3</sup> cfu/mL
B) >10<sup>4</sup> cfu/mL |
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T/F Anaerobes RARELY cause UTI despite their prevalence in fecal flora
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T
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T/F Candida spp. increasingly recognized as causes of UTI especially in catheterized patients
& in patients who rec'd previous treatment for enterococcal UTI |
T
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Top 2 causes of uncomplicated UTI
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E. coli (75 - 90%)
S. saprophyticus (5 -15%) |
