Bacteria Flashcards
Staphylococcus Aureus: what is it and what 4 tests are positive, where is it found and what does it cause, and what protein acts as its virulence factor?
- beta-hemolytic gram (+) coccus that is Catalase (+), Coagulase (+) and can ferment Mannitol (yellow)
- part of normal nose and skin flora that can cause bacterial pneumonia of the UPPER respiratory tract w/patchy infiltrate on X-Rays
- also acquired from contaminated mayo and meats
- Protein A (part of cell wall) prevents opsonization
Staphylococcus Aureus: what 3 findings is it the most common cause of (SA,O,E), what 4 clinical findings does it cause, and what 3 things does its exotoxin cause?
- most common cause of septic arthritis, adult osteomyelitis, and infective endocarditis
- causes impetigo (honey crust), furuncles, carbuncles, and cellulitis
- exotoxins cause: scalded skin syndrome, toxic shock syndrome, and rapid onset food poisoning (1-8 hours –> vomiting)
Staphylococcus epidermidis & saprophyticus: what are they and what 2 tests are positive for them, and what are the clinical implications of each?
- gram (+) cocci that are Catalase (+), Urease (+), and Coagulase (-)
SE: part of normal flora on skin; infects implants, catheters, and heart valves (MCC endocarditis); produces a biofilm that helps it stick
SS: UTIs in sexually active females (second most common cause)
Group A Streptococcus: what is it, what 3 clinical findings does it commonly cause, and what 3 things is its exotoxin associated with?
- gram (+) cocci that produce a Hyaluronic Acid capsule (no immune response) and is Beta hemolytic
- cause impetigo (honey crust), strep throat, and is the most common cause of skin infection (cellulitis)
- exotoxin associated with Scarlet Fever, Toxic Shock Syndrome (SPE A/C), and Necrotizing Fasciitis (SPE B)
What 3 things does the Group A Strep exotoxin produce in Scarlet Fever?
- strawberry tongue, pharyngitis, and a “sandpaper” rash that spares the palms/soles/face
How is the Group A Strep protein M associated with Rheumatic Fever?
- caused by untreated Strep A pharyngitis
- protein blocks phagocytosis and complement; leads to CROSS-REACTIVE Abs that cause pancarditis and mitral valve stenosis
- MOLECULAR MIMICRY with the heart
JONES criteria and Rheumatic Fever
J - joints (migratory polyarthritis)
O - myocarditis
N - subQ nodules (on extensor surfaces)
E - erythema marginatum (hive-like “C” shape)
S - Syndenhams chorea (rapid hand/face movements)
Post Strep A Glomerulonephritis
- immune complex deposition in glomeruli that causes renal damage and nephritic syndrome
- causes “cola-colored” urine and nephritic syndrome several weeks after
- follows pharyngitis OR tissue infection
How is Strep A pharyngitis diagnosed and what are two other virulence factors for Strep A? (SSD)
diagnose: antibodies against Strepolysin O (hemolytic virulence factor)
- other virulence factors: streptokinase (plasminogen to plasmin) and DNAses
Streptococcus agalactiae (Group B Strep): what is it and what 3 things is it positive for, how does Bacitracin affect it compared to Group A Strep, and what are the 3 clinical findings it causes (MSP)?
- encapsulated gram (+) cocci that is hippurate (+) and CAMP (+) –> (inc. hemolytic zone when plated with S. Aureus), and Beta hemolytic
- Bacitracin INSENSITIVE (Strep A is Bacitracin SENSITIVE)
- most common cause of neonatal meningitis, sepsis, and pneumonia (screen moms at 35-37 weeks)
Streptococcus pneumonia: what is it and what are 3 major findings for it, what does its protease do, and what 4 things is it the most common cause of? (MOPS)
- encapsulated gram (+) lancet-shaped diplococci that is ALPHA hemolytic, OPTOCHIN sensitive, and is bile-soluble
- causes lobar pneumonia (rust sputum) and has IgA protease that cleaves IgA Abs
- is the most common cause of meningitis, otitis media, pneumonia, and sinusitis
- sickle cell patients are more susceptible to infection
Streptococcus viridans: what is it and what are 3 major findings for it, what two things do S. mutans/sanguinis cause, and how do they use Dextrans?
- non-encapsulated gram (+) cocci that is ALPHA hemolytic, OPTOCHIN insensitive, and is bile-insoluble
- mutans and sanguinis cause tooth decay and cavities (normal mouth flora) and can cause bacterial mitral valve endocarditis
- uses DEXTRANS to adhere to platelets and enamel
Enterococcus faecalis and faecium (Group D Strep): what are they and what two things do they grow in, and what 3 things do they commonly cause (UEB)?
- gram (+) cocci (faecium is most dangerous) that grow in 6.5% hypertonic saline and in bile salts
- commonly cause UTIs, endocarditis, and biliary tree infections
Bacillus anthracis and cereus: what is it, what does it cause cutaneously and pulmonarily, and what two exotoxins does B. anthracis have?
- encapsulated (poly-y-D-glutamic acid) gram (+) spore forming bacilli that form chains and is obligate aerobe
- causes cutaneous anthrax (necrotic lesion w/erythematous ring, edema, and eschar)
exotoxins:
- Lethal Factor - cleaves MAP Kinase (no cell growth)
- Edema Factor - inc. cAMP (edema)
- Wool Sorter’s = inhaled form causing hemorrhagic mediastinitis (chest X-Ray shows widened mediastinum or pleural effusions)
What two clinical findings does ingesting Bacillus cereus cause and what is it commonly associated with?
- ingestion of preformed toxin causes early onset food poisoning (6 hours) and watery vomit/abdominal cramps (6-15 hours)
- usually associated with eating reheated fried rice
Clostridium tetani: what is it and how is it introduced into the body, how does it travel and what does its toxin do, and what 3 clinical findings does it cause?
- gram (+) spore-forming bacilli that are obligate anaerobes associated with barbed wire puncture wounds and rusty nails (inactive spores in soil)
- travels retrograde up the spinal cord; tetanus toxin cleaves SNARE proteins (no GABA or Glycine from Renshaw cells = no motor cell inhibition)
- causes spastic paralysis of neck/back/spine, Risus Sardonicus (evil grin) and Lockjaw
Clostridium botulinum: what is it and what is it associated with, how does it cause paralysis, and what are some of the first signs of infection?
- gram (+) spore-forming bacilli that is an obligate anaerobe associated with improperly canned foods
- cleaves SNARE proteins that prevent Ach release from presynaptic terminal
- cause descending flaccid paralysis starting from cranial nerves –> causes ptosis/diplopia
- infantile form from ingesting spores from honey (GI tract is not properly colonized yet)
Clostridium difficile: what is it and how is it spread, what is it clinically associated with, and what do its two toxins (AB) cause?
- gram (+) spore-forming bacilli that is an obligate anaerobe commonly spread by Clindamycin use w/improper handwashing –> WASH YOUR FUCKING HANDS YOU PLEB
- commonly associated with nosoconial diarrhea (diagnose with detection of exotoxins in stool)
Exotoxin A: bind brush border = watery diarrhea
Exotoxin B: depolymerize actin = pseudomemb. colitis
Clostridium perfringens: what is it and how is it commonly spread, what three clinical findings does it cause (GG/FP/WD), and how is it characterized when it is plated on agar?
- gram (+) spore-forming bacilli that is an obligate anaerobe (in dirt/dust) commonly associated with motorcycle accidents and deep penetrating combat wounds
- causes gas gangrene (clostridial mynecrosis) via ALPHA TOXIN (lecithinase that cleaves membranes and RBCs)
- ingestion of spores causes late onset food poisoning (watery diarrhea)
- produces a double zone of hemolysis on plating
Corynebacterium diphtheriae: what is it and what does it look like, what 4 clinical findings does it cause, and what does it look like on agar?
- gram (+) bacilli (NO SPORES –> Resp. Droplets) that form V/Y-shaped chains and have metachromatic granules that stain red (rest of bacilli stain blue)
- toxin inhibits EGF-2 via ADP ribosylation and causes pseudomembrane formation of tonsils and throat, lymphadenopathy (“Bulls Neck”), and is cardiotoxic
- can also cause demyelination causing paralysis in posterior pharyngeal wall and soft palate
- grow as dark black colonies on cysteine-tellurite agair
What test is used to differentiate between toxogenic and non-toxogenic C. diphtheriae?
ELEK test
Listeria monocytogenes: what is it and how is it transmitted, what test is it positive for, and what two populations does it commonly cause meningitis in?
- facultative intracellular gram (+) bacilli that are WEAKLY beta hemolytic and having tumbling motility outside cells and rocket motility inside cells
- Catalase (+); survives in freezing temps (milk, cheese)
- pregnant women at risk (no soft cheese) and is the third leading cause of neonatal meningitis
- also a common cause of meningitis in adults older than 60 yo
Acintomyces israelii: what is it and where is it commonly found, and what 3 clinical findings does it present with?
- gram (+) filamentous branching bacilli that is an obligate anaerobe commonly found in the mouth
- usually infect after JAW TRAUMA causing abscesses in the face and neck, and cutaneous sinus tracts
- hard yellow (sulfur) granules drain from the sinus tract
Nocardia asteroides: what is it and where is it found, what two tests are positive for it, and what 4 clinical findings does it cause?
- gram (+) filamentous branching bacilli that is an obligate aerobe (in soil) that stain acid-fast (Carbol-Fuchsin); commonly infects immunocompromised
- Catalase (+), Urease (+)
- causes lung cavitations, pneumonia w/lung abscesses, ring-enhancing lesions in brain, and cutaneous lesions
What is Nocardia asteroides commonly misdiagnosed as?
Tuberculosis
Neisseria commonalities: what are they, what two mediums do they grow on, and what are their two virulence factors?
Bonus: who is at inc. risk of infection from Neisseria?
- gram (-) diplococci that is Oxidase (+)
- grows on Chocolate Agar and Thayer Martin Agar (VPN) –> cannot grow on Blood Agar
- increased susceptibility in people with MAC deficiencies
Virulence Factors: IgA protease and pili (antigenic var.)
Neisseria meningitis: how is it spread and what does it ferment, and what two clinical findings does it cause? (S/WFS)
- encapsulated; spread via respiratory droplets in close-quarters; ferments glucose AND maltose
- outer lipooligosaccharide causes sepsis (inc. capillary permeability –> hypovolemic –> SHOCK)
- also causes Waterhouse-Friderichsen Syndrome = bilateral adrenal hemorrhage and hemorrhagic skin lesions
Neisseria gonorrhea: what is it contained in, what 4 clinical findings does it cause, and how can it affect newborns?
- non-encapsulated sexually transmitted disease; facultative intracellular within neutrophils
- progressive to pelvic inflammation, white mucopurulent discharge from urethra/vagina, septic arthritis/polyarthralgias (asymmetric –> knee)
- causes Fitz Hugh Curtis Syndrome: inflamed peritoneum and capsule of liver with “violin-string” adhesions between them
- can infect newborns = conjunctivitis (blindness occurs if not treated)
Klebsiella pneumonia, Enterbacteric spp., Serratia marcensens:
What are they and what do they commonly cause, what do they ferment, and what is the difference between Enterbacteris/Serrtia marcenses and Klebsiella pneumonia?
- gram (-) bacilli that are common causes of nosocomial UTIs and pneumonia (multidrug resistance)
- lactose fermenting (pink on MacConkey)
ES: motile, SM: motile, red pigment
KP: polysaccharide capsule; causes abscesses and aspiration pneumonia (currant jelly sputum); Urease (+) and immotile; looks like TB chest X-ray
Salmonella enteritidis and typhi: what are they and what cells do they live in, what do they commonly cause, and what are the differences between the two?
- motile, encapsulated gram (-) bacilli that form black colonies on Hektoen Agar; acid-labile; facultative intracellular (macrophages)
- causes osteomyelitis in sickle cell patients
SE: chickens; causes self-limited gastroenteritis
ST: colonizes gallbladder; Typhoid Fever presents w/”rose spot” rash and “pea soup” stool
How do Salmonella enteritidis/typhi and Shigella spp. get effector proteins into host cells?
- utilize a type III secretion system
Shigella sonnei and dysenteriae: what are they and what cells do they live in, what 4 clinical findings do they normally cause (BD/GE/HUS), and what toxin do they produce?
- immotile, gram (-) bacilli that form GREEN colonies on Hektoen Agar; acid-resistant; facultative intracellular (invade M cells in Peyers Patches)
- causes bloody diarrhea and gastroenteritis (diagnose with leukocytes in stool); HUS in children
- causes Hemolytic Uremic Syndrome (acute kidney injury and thrombocytopenia) and Microangiopathic Hemolytic Anemia (shistocytes)
- Shiga Toxin (SD) = inactivates 60s ribosomal subunit
E. coli: what are they and how do they stain, and what two clinical findings are they the most common cause of?
- encapsulated (K Ag) gram (-) bacilli that ferment lactose (pink MacConkey) and form metallic green colonies (EMB agar); Catalse (+)
- most common cause of UTIs and gram (-) sepsis
What E. coli strains cause neonatal meningitis?
only strains with the K1 capsular antigen
Enterohemorrhagic and Enterotoxogenic E. coli: how are they transmitted and what do their toxins do, and what are their clinical presentations (1:3)?
EHEC: from undercooked meat (0157:H7 no sorbitol)
- causes bloody diarrhea (Shiga-like toxin (60s sub))
- toxin = Hemolytic Uremic Syndrome
ETEC: “Traveler’s Diarrhea/ Montezuma’s Revenge”)
- from contaminated water
- watery diarrhea, abdominal cramps, nausea/vomit
- produce Heat Labile Toxin = inc. cAMP
- produce Heat Stabile Toxin = inc. cGMP
Yersinia entercolitica: what is it and how is it transmitted, and what two clinical findings does it cause?
- bipolar staining, encapsulated gram (-) bacilli transmitted by pet poop and contaminated milk (outbreak at daycares)
- resists cold temperatures
- causes bloody diarrhea and can mimic appendicitis
Yersinia pestis: what is it and how is it transmitted, what 4 clinical findings does it cause, and how does it deliver its toxin?
- bipolar staining, encapsulated gram (-) bacilli transmitted by fleas from rodents (rats/prairie dogs)
- BUBONIC PLAGUE
- cause buboes (swollen LNs with erythema), disseminated can cause tissue necroses, DIC, septic shock , hemorrhage
- both use Type III system for Yops secretion into host cells
Campylobacter jejuni: what is it and how is it transmitted, and what 3 clinical findings does it cause (BD/RA/GBS)? What two tests is it positive for?
- gram (-) curved bacilli that are thermophilic transmitted through poultry (livestock) fecal-oral transmission; Oxidase (+) and Catalase (+)
- causes bloody diarrhea (invades intestinal epi), reactive arthritis
- causes Guillian-Barre Syndrome (bilateral ascending weakness and loss of reflexes)
Vibrio cholerae: what is it and how is it transmitted, what is it positive for and how does it grow, and what clinical finding does it cause?
- gram (-) comma-shaped bacilli endemic in developing countries (fecal-oral transmission) that attach but do NOT invade intestinal mucosa
- Oxidase (+), acid-labile, grow in alkaline media
- causes “rice-water stool” (watery diarrhea) due to cholera toxin = inc. cAMP (Gs ALWAYS on)
H. pylori: what is it and what two tests are positive for it, and what two clinical findings does it cause?
- gram (-) curved helical bacilli that are Urease and Oxidase (+)
- causes 95% of gastric and duodenal ulcers (inc. risk of gastric adenocarcinoma and MALT lymphoma)
Proteus Mirabilis: what is it and what test is positive for it, and what two clinical findings does it cause?
- gram (-) bacilli w/swam motility when plated and is Urease (+)
- produces staghorn calculi (struvite stones) with UTIs due to alkaline environment and has a “fishy” odor
Bordatella pertussis: what is it and how is it transmitted, what do its two toxins do, and what is the second stage of infection called?
- gram (-) bacilli w/filamentous hemagglutin (respiratory epi); transmitted through respiratory droplets
- pertussis toxin ribosylates Gi = inc. cAMP and causing massive lymphocytosis (cant enter lymphoid tissue)
- tracheal cytotoxin: destroys ciliated epithelium
- second stage of infection (2-6 wks) = Whooping Cough and can last months (100 day cough)
H. influenza: what is it and how is it transmitted, what are 3 clinical findings it causes (EOM-B!), and who is at inc. risk of infection?
- encapsulated gram (-) coccobacilli that grows on Chocolate Agar (requires factor 5/10) and is transmitted via respiratory droplets
- causes epiglottitis (cherry red), otitis media, meningitis (Type B ONLY)
- inc. risk of infection of sickle cell pts and asplenic pts.
Legionella pneumophilia: what is it and how is it plated, what test is it positive for, and what are the two diseases (with presentation) that it causes (P/L)?
- gram (-) bacilli plated on Buffered Charcoal Yeast Extract (weakly gram (-), requires silver); requires iron and cysteine for growth
- Oxidase (+), diagnose with urine Ag test
Pontiac Fever: self-limiting flu-like symptoms
Legionnaires Dz: inc. risk in smokers; PNEUMONIA
- patchy unilobar infiltrates (X-Ray)
- hyponatremia, diarrhea, confusion, high fever
Psuedomonas aeruginosa: what is it and how is it transmitted, what two tests is it positive for, and what are 5 clinical findings that it causes (O/NU/HTF/S/OE)?
- motile encapsulated gram (-) bacilli that lives in water and is Oxidase and Catalase (+); produces blue/green pigment on plate with “fruity grape” odor; obligate aerobe
- common nosocomial infection (CF/burn pts), inc. risk of osteomyelitis in IV drug users/diabetics
- common cause of nosocomial UTIs (catheter), “hot tub” folliculitis, sepsis (ecythma gangrenosum = black necrotic lesions), and otitis externa
- Exotoxin A –> ribosylates EF-2 (dec. protein synth)
Bartonella Henselae: what is it and how is it transmitted, how is it visualized, and what are the two clinical manifestations it causes?
- zoonotic bacilli that is transmitted by cats and fleas, and is visualized via Warthrin Starry Stain (silver)
- causes “Cat Scratch Disease” in immunocompetent: axillary lymphadenopathy
- causes Bacillary Angiomatosis in immunocompromised: skin lesions (red papules –> large vascular nodules
Brucella spp: what is it and how is it transmitted, how does it present acutely and chronically, and what types of cells does it live in?
- facultative intracellular zoonotic coccobacilli transmitted by direct contact or consumption of livestock; live in macrophages
- acute: undulent fever, night sweats, anorexia
- chronic: osteomyelitis
- commonly target liver and spleen
Francisella Tularensis: what is it and how is it transmitted, what 4 clinical findings does it cause, and what types of cells does it live in?
- zoonotic coccobacilli commonly transmitted by rabbits and Dermacentor ticks and are facultative intracellular (macrophages)
- cause skin ulcers and necrosis at tick bite site, and travels lymph system to liver/spleen where it causes necrosis and caseating granulomas; also regional lymphadenopathy
Pasturella Multocida: what is it and how is it transmitted, what two tests is it positive for, and what is its clinical presentation?
encapsulated zoonotic coccobacilli transmitted by dog/cat bites/scratches; is Catalase and Oxidase (+)
- causes cellulitis within 24 hours, osteomyelitis
- cultured on 5% sheeps blood agar = bipolar staining
M. tuberculosis: how is it plated, what does it look like and what cells does it live in, and what complex does it form and where?
- acid-fast (carbolfuchsin) obligate aerobe cultured in Lowenstein Jensen medium; replicate in macrophages
- cord factor causes clumping into “serpentine cords”
- mainly affects middle/lower lobes of lung producing GHON COMPLEX (with hilar lymphadenopathy and parenchymal granuloma)
- causes caseating granuloma that can be walled off and become (latent) –> usually resolves by fibrosis
Miliary Tuberculosis and reactivation of Latent TB: what are they and what two disease states can they lead to?
MTB: when immune system FAILS to clear infection and it is allowed to disseminate (potentially FATAL)
LTB: use of TNF-alpha inhibitors, affects UPPER lobes of lung = cough, hemoptysis, and night sweats
**Potts Disease: vertebral column infection (lower thoracic/upper lumbar)
**CNS: cavitary lesions and brain tuberculomas
Mycobacterium leprae (Tuberculoid and Lepromatous): what are they and how are they transmitted, and what is the difference between Tuberculoid and Lepratomatous versions?
- acid fast (carbolfuchsin) that thrives in the cold (attacks extremities) and is transmitted by Armadillos
Tuberculoid: incite Th1 cells = cell-mediated response causing macrophages to phagocytose bacterium; well-demarcated, hairless skin lesions
Lepratomatous: incite Th2 cells = humoral response correlated with weak Th1 response that DOESN’t contain the bacterium; spreads via human-human contact and presents with “glove and stocking” neuropathy and poorly demarcated lesions on extensor surfaces, also LEIONINE FACIES
Borrelia Burgdorferi: what is it and how is it transmitted, what is it visualized with, and what are the 3 stages of infection and their clinical presentations?
- spirochete causing Lyme Disease in Northeastern US; transmitted by Ixodes tick; visualized with Wright/Giemsa staining
Stage 1: bulls eye rash (erythema chorinicum migrans)
- with flu-like symptoms: fever and sweating
Stage 2: heart block via myocarditis (early disseminated) and bilateral Bell’s Palsy
Stage 3: large joint arthritis and encephalopathy
Leptospira interrogans: what is it and how is it transmitted, what does it cause (Conj), and what disease can it produce (WD - R/H)
- spirochete with “question mark” appearance that is transmitted through water infected by animal urine
- causes fever, non-suppurative conjunctivitis
- causes Weil’s Disease = renal/hepatic failure (acute liver injury and liver dysfunction/jaundice)
Treponema pallidum: what is it and how is it transmitted, and what are the clinical presentations of primary, secondary, tertiary, and congenital variants?
- spirochete with “spiral-shaped” appearance (Dark Field microscopy)
- causes SYPHILIS; chancres on genitals and anus (primary)
- secondary syphilis: diffuse maculopapular rash of palms and soles, condyloma lata (flat-top lesions) on gentials
- tertiary syphilis: gumma, “tree-bark” ascending aortic aneurysm (destruction of vasa vasorum), tabes dorsalis (demyelination of posterior spinal cord), and Argyll-Robertson pupils (no light reactivity)
congenital: saber shins (ant. tibia bowing), saddle nose, Hutchinson Teeth (notched)/Mulberry Molars (overgrowth), and deafness
What 5 conditions can cause false-positive VDLR tests for Syphilis? (MRSLI)
mono, rheumatoid factor, systemic lupus erythematosus, leprosy, and IV drug use
use FTA-ABS to confirm
What is the Jarisch-Herxheimer Rxn and what is it associated with?
- fever and chills caused by exotoxin release after death of T. pallidum bacteria upon antibiotic therapy
Chlamydia spp: what are they and what do they look like, what are their two life cycle stages, and what is a common diagnostic tool used to ID them?
- gram indeterminate, obligate intracellular that are weakly gram (-) (lack muramic acid); intracellular bodies can be visualized with Giemsa
elementary stage: infectious, no replication, extracell.
secondary stage: replicative, intracellular
- form elementary bodies and leave host cells
- diagnosed with NAAT test
Chlamydia trachomatis: what are the clinical presentations for A-C, D-K, and L1-L3? What Syndrome can Chlamydia lead to?
A-C: blindness (leading cause worldwide)
- hand to eye contact
D-K: STI –> PID (if untreated)
- watery vaginal/urethral discharge
- can cause congenital conjunctivitis and pneumoniae
- Staccato cough
L1-L3: STI
- lymphogranuloma venerulum (tender inguinal lym)
**Reiter’s Syndrome = reactive arthritis and UVitis/urethritis
Chlamydia pneumonia and psittaci: what do these two cause clinically?
CA - atypical pneumonia (mainly elderly adults)
CP - atypical pneumonia (via bird droppings)
Coxiella burnetii: what is it and how is it spread, and what does it cause clinically?
- gram indeterminate gram (-) that does NOT have a rash and is transmitted via spores in farm animal droppings (aerosol transmission); obligate intracellular
- causes Q fever: headache and dry cough, granulomatous hepatitis
Gardenella vaginalis: what is it and where does it grow, what does it cause clinically, and what are two ways to diagnose it?
- gram indeterminante that grows when normal vaginal flora is disrupted and the pH increases (> 4.5) (bacterial overgrowth)
- cause thin, gray-white, “fishy” vaginal discharge
- diagnosed with “Whiff Test” and clue cells (epithelial cells coated in discharge on wet mount)
Mycoplasm pneumoniae: what is it and how does it grow, who is it commonly seen in, and what 3 clinical findings does it present with? (WP/H/IA)
- gram indeterminante that lacks a cell wall (no gram staining); membrane contains cholesterol (ONLY BACTERIA WITH THIS); grows on Eaton’s Agar
- common in military recruits living close together and in adults < 30 yo
- patchy infiltrate on X-Ray that appears worse than pts. symptoms, causes “Walking” pneumonia and RBC hemolysis at cold temps (IgM cold aggluttins)
Rickettsia spp: what are they and what do they need to survive, how are they diagnosed (WF), and what are 3 clinical findings of infection (H/F/VV)?
- gram indeterminante bacteria that are obligate intracellular and are WEALKY gram (-) coccobaccili
- host eukaryotic cells provide source of CoA/NAD, which Rickettsia cannot make itself
- use Weil-Felix agglutination test to diagnose
- causes headaches, fever, and small vessel vasculitis (petechial or maculopapular rash)
Rickettsia prowasekii: how is it transmitted and who is at risk of infection, what are 5 clinical findings of it (RMAPE), and what disease does it cause?
- transmitted by lice feces that get scratched into the vasculature
- inc. infection risk in military recruits and POWs
- rash develops on trunk and spreads to extremities (spares face, palms, and soles)
- causes epidemic Typhus: myalgias, arthralgias, pneumonia, and encephalitis
Rickettsia rickettsii: what is it transmitted by, how does it develop, and what disease state does it cause?
- transmitted by Dermacentor tick bites
- rash develops after 2-14 days, starting on the wrists and ankles, and spreading centrally to the trunk
- causes Rocky Mountain Spotted Fever: fever, headache, myalgias, and rash
