Bacteria Flashcards
All bacterial capsules contain polysaccharide except which one?
Bacillus anthracis which contains D-glutamate (a polypeptide)
Are lipoteichoic acids on gram positives or negatives?
Positives
What do lipoteichoic acids induce in host’s immune system?
TNF and IL-1
What does Lipid A induce in host’s immune system?
TNF, IL-1, and IL-6
Is endotoxin (LPS) on gram positives or negatives?
Negatives
Where exactly are beta-lactamases located on a bacterium?
In the periplasm layer of gram negatives
What is the purpose of a bacterium’s capsule?
Protects against phagocytosis
What does catalase do?
Catalyzes the following reaction: 2H2O2 –> O2+2H2O
What is LPS composed of?
Lipid A (toxic), core polysaccharides, and O antigen
A deficiency in C5-C9 predisposes a patient to disease by which species of bacteria?
Neisseria
What are the 7 Gram positive rod species?
Clostridium, Propionibacterium acnes, Gardnerella, Corynebacterium, Bacillus, Listeria, Mycobacterium
What are the 2 pleomorphic bacterial species? And which stain must you use to visualize them?
Rickettsiae and Chlamydiae; Giemsa stain
What are the 3 spirochete bacterial species? And how can you visualize them?
Borrelia, Leptospira, Treponema; Dark field microscopy
Which bacterial species has no cell wall?
Mycoplasma
Giemsa stain is used to visualize which bacterial species?
Chlamydia, Borrelia, Rickettsiae, Trypanosomes, Plasmodium; “Certain Bugs Really TRY my Patience”
PAS stain is used to visualize which bacterial species?
Stains glycogen, used to diagnose Whipple disease (Tropheryma whipplei)
Ziehl-Neelsen (carbol fuchsin) stain is used to visualize which bacterial species?
Acid-fast organisms (Nocardia, Mycobacterium)
India ink stain is used to visualize what?
Cryptococcus neoformans
Silver stain is used to visualize what?
Fungi, Legionella, H pylori
Chocolate agar with factors V (NAD+) and X (hematin) is used to grow which bug?
H flu
Thayer-Martin agar (or VPN) media contains what?
Vancomycin (inhibits gram +), Polymyxin (inhibits gram - except Neisseria), and Nystatin (inhibits fungi)
Thayer-Martin agar (or VPN) is used to isolate which bug?
Neisseria spp.
Bordet-Gengou (potato) agar is used to isolate which bug?
Bordetella pertussis
Tellurite agar (Loffler medium) is used to isolate which bug?
C diphtheriae
Lowenstein-Jensen agar is used to isolate which bug?
Mycobacterium TB
Eaton agar - which bug?
M pneumoniae “don’t EAT ON ice”
Charcoal yeast extract agar buffered with cysteine and iron (aka BYCE) is used to isolate which bug?
Legionella “SS Cysteine”
Sabouraud agar is used to isolate what?
Fungi
Which bugs are obligate aerobes?
Nocardia, Pseudomonas, and MycoBacterium “Nagging Pests Must Breathe”
Which bugs are obligate anaerobes?
Clostridium, Bacteroides, and Actinomyces (lack catalase and/or superoxide dismutase) “anaerobes Can’t Breathe Air”
Which class of antibiotic is ineffective against anaerobes?
Aminoglycosides
Which bugs are obligate intracellular?
Rickettsia, Chlamydia
Which bugs are facultative intracellular?
Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francisella, Legionella, Yersinia pestis; “Some Nasty Bugs May Live FacultativeLY”
Which bacteria are encapsulated?
S pneumo, H flu, Neisseria meningitidis, E coli, Salmonella, Klebsiella pneumo, group b Strep ; “SHiNE SKiS”
Patients with chronic granulomatous disease are susceptible to which organisms?
Catalase positive organisms because they are deficient in NADPH oxidase
How does Protein A evade the immune system and which bug is it associated with?
S aureus; Binds Fc region of IgG and prevents opsonization and phagocytosis
Which bugs express IgA protease?
S pneumo, H flu type B, and Neisseria
How does M protein evade the immune system and which bug is it associated with?
Group A strep; Helps prevent phagocytosis
Which 5 bugs are lactose fermenters?
E coli, Klebsiella, Enterobacter, Citrobacter, Arizona
What is the heat stability of endotoxin?
Stable at 100 degrees C for 1 hour
What is the genetic location of genes of exotoxins? Of endotoxins?
Plasmid/bacteriophage and bacterial chromosome, respectively
What is the heat stability of exotoxin?
Destroyed rapidly at 60 degrees C (except staph enterotoxin)
What are the names and mechanisms of Staph aureus’ exotoxins?
TSST-1; Brings MHC II and TCR in proximity to outside of antigen binding site to cause overwhelming release of IFN-gamma and IL-2 –> shock
Enterotoxin; Rapid-onset food poisoning
Exfoliative toxin; Scalded skin syndrome
What are the names and mechanisms of E coli’s exotoxins (3)?
Shiga-like toxin (SLT) EHEC; Inactivates 60S ribosome by removing adenine from rRNA –> dysentery
Heat-labile toxin (LT) ETEC; Overactivates AC to increase cAMP which leads to increased Cl secretion in gut and water efflux
Heat-stabile toxin (ST) ETEC; Overactivates GC to increase cGMP which leads to decreased resorption of NaCL and water in gut
What is the name and mechanism of Vibrio cholerae’s exotoxin?
Cholera toxin; A-B toxin that overactives AT and increases cAMP by permanently activating Gs –> increased Cl secretion in gut and water efflux –> “rice water” diarrhea
What are the names and mechanisms of Streptococcus pyogene’s exotoxins?
Streptolysin O; Protein that degrades cell membrane
Exotoxin A; Brings MHC II and TCR in proximity to outside of antigen binding site to cause overwhelming release of IFN-gamma and IL-2 –> shock
What is the name and mechanism of Bacillus anthracis’ exotoxin?
Edema factor; Mimics the AC enzyme to increase cAMP
What is the name and mechanism of Bordetella pertussis’ exotoxin?
Pertussis toxin; Overactivates AC (increasing cAMP) by ribosylating and disabling Gi, impairing phagocytosis to permit survival of microbe
What is the name and mechanism of Clostridium perfringens’ exotoxin?
Alpha toxin; Phospholipase (lecithinase) that degrades tissue and cell membranes
What is the name and mechanism of Shigella’s exotoxin?
Shiga toxin; Inactivates 60S ribosome by removing adenine from rRNA, ST also enhances cytokine release causing HUS
What is the name and mechanism of Pseudomonas aeruginosa’s exotoxin?
Exotoxin A; Inactivate EF-2
What is the name and mechanism of Clostridium botulinum’s exotoxin?
Botulinum toxin; Cleaves Snare proteins that release ACh vesicles –> descending flaccid paralysis
What is the name and mechanism of Clostridium tetani’s exotoxin?
Tetanospasmin; Cleaves Snare proteins that release GABA and glycine vesicles –> spastic paralysis
What is the name and mechanism of Corynebacterium diphtheriae’s exotoxin?
Diphtheria toxin; ADP-ribosylationof EF-2 prevents protein synthesis
What is the most common cause of septic arthritis?
S aureus
What is the most common cause of osteomyelitis?
S aureus
What is the treatment for MRSA?
Vancomycin
What is the treatment of MSSA?
Naphcillin
What is the treatment for staph epidermidis and saprophyticus?
Vancomycin
What is the second most common cause of UTIs in sexually-active young women?
Staph saprophyticus
Strep pneumo is the #1 cause of what?
“MOPS” Meningitis, otitis media (kids), pneumonia, and sinusitis
Pneumonia with rust-colored sputum may indicate infection with what bug?
S pneumo
What is the virulence factor of S pneumo?
IgA protease, capsule
What is the treatment of S pneumo?
Macrolides or ceftriaxone
The adult S pneumo vaccine is what kind of vaccine?
A polysaccharide vaccine with an IgM response
The child S pneumo vaccine is what kind of vaccine?
A conjugate vaccine with an IgG response
What is the #1 cause of necrotizing fasciitis?
Group A strep (S pyogenes) - specifically SPEb protease toxin
S pyogenes capsule is made of what?
Hyaluronic acid (also found in humans, therefore not immunogenic)
What is the #1 cause of erysipelas?
S pyogenes
What causes Scarlet fever?
SPE exotoxin of S pyogenes
What are the main symptoms of scarlet fever?
Reddening of the tongue, pharyngitis, widespread rash that spares the face
Which bug causes Toxic shock-like syndrome?
S pyogenes
How long after infection does post-strep glomerulonephritis occur?
2 weeks after onset of initial infection
What is the main virulence factor responsible for rheumatic fever?
M protein of S pyogenes - prevents phagocytosis
In bacterial genetics, what is Transformation?
Ability to take up DNA (from cell lysis) from environment.
In bacterial genetics, what is Conjugation?
Two types of conjugation
F+ x F- : F+ plasmid contains genes for sex pilus and conjugation. Plasmid (dsDNA) is replicated and transferred through pilus from F+ cell to F- cell. No transfer of chromosomal genes.
Hfr x F- : F+ plasmid can be incorporated into bacterial chromosomal DNA (high frequency recombination). Replication of incorporated plasmid DNA may include some flanking chromosomal DNA.
In bacterial genetics, what is Transposition?
Segment of DNA (transposon) that can “jump” from one location to another, can transfer genes from plasmid to chromosome and vice versa. Excision may include some flanking chromosomal DNA, which can be incorporated into a plasmid and transferred to another bacterium.
In bacterial genetics, what is Generalized Transduction?
Lytic phage infects bacterium, leading to cleavage of bacterial DNA. Parts of bacterial chromosomal DNA may become packaged in viral capsid. Phage infects another bacterium, transferring these genes.
In bacterial genetics, what is Specialized Transduction?
Aka prophages. Lysogenic phage infects bacterium; viral DNA incorporates into bacterial chromosome. When phage DNA is excised, flanking bacterial genes may be excised with it. DNA is packaged into phage viral capsid and infects another bacterium.
Genes for which 5 bacterial toxins are encoded in lysogenic phages?
Shiga-like toxin, Botulinum toxin, Cholera toxin, Diphtheria toxin, Erythrogenic toxin of S pyogenes
Which virulence factor of S pyogenes is responsible for rheumatic fever and why?
M protein - Very antigenic and illicits a very strong humoral response. Molecular mimicry causes Abs to attack the myosin in cardiac muscle.
What is the most severe form of rheumatic fever?
Myocarditis
What is the clinical presentation of rheumatic fever?
Acute migratory polyarthritis, carditis, subcutaneous nodules, erythema marginatum, Sydenham chorea (JONES criteria)
How does acute glomerulonephritis from a GAS infection present?
Cola-colored urine and facial edema
How can we detect a recent GAS infection?
ASO titer (anti-streptolysin O antibodies)
Can early treatment of GAS infection prevent rheumatic fever?
Yes
Can early treatment of GAS infection prevent acute glomerulonephritis?
No
What is the treatment of GAS infection?
Penicillin
What is the role of GAS’s virulence factor streptokinase?
Converts plasminogen –> plasmin *plasmin is fibrinolytic
What is the role of GAS’s virulence factor streptolysin O?
(Oxygen labile) Lyses RBCs
What does GBS cause in babies?
Pneumonia, meningitis, and sepsis.
Which Strep bacterium tests hippurate positive?
GBS
What is the CAMP test and what does it test for?
GBS; GBS produces CAMP factor, which enlarges the area of hemolysis of S aureus
Which of the two enterococi is more common?
Enterococcus faecalis > Enterococcus faecium
What is a common bug that causes subacute endocarditis following GI/GU procedures?
Enterococcus
What are the three most common diseases caused by enterococcus?
UTIs, biliary tract infections, and subacute endocarditis
What can be used to treat enterococcus?
Linezolid or tigecycline (resistant even to vancomycin, VRE)
What is the most life-threatening manifestation of Corynebacterium diphtheriae?
Myocarditis and arrhythmias
What test is used to determine the toxicity of Corynebacterium diphtheriae?
Elek test for toxin
What kind of vaccine is the vaccine for Corynebacterium diphtheriae?
Toxoid - IgG response
A blood infection with Strep bovis would cause you to look for what in a patient?
Colon cancer
What kind of vaccine is the tetanus vaccine?
Toxoid
Describe floppy baby syndrome
Ingestion of spores of Clostridium botulinum causes flaccid paralysis - adults cannot get sick with spores due to mature gut flora
Is C botulinum an ascending or descending paralysis?
Descending
What are the 2 diseases caused by C perfringens?
Gas gangrene and late-onset food poisoning (ingestion of spores)
What is the treatment of C perfringens?
IV penicillin G
Which clostridium species causes a double zone of hemolysis on blood agar?
C perfringens
What toxins are produced by C dif and what are their mechanisms of action?
Exotoxin A: Binds to brush border and causes inflammation, cell necrosis, and watery diarrhea
Exotoxin B: Disrupts cytoskeleton integrity by depolymerizing actin –> pseudomembranous colitis
How is C diff diagnosed?
Detection of one or both toxins in the stool
How is C diff treated?
Metronidazole or oral vancomycin. Recurring cases may benefit from fecal transplant.
What are anthrax’s toxins and their MOAs?
EF (edema factor): Activates AC, increase in cAMP, edema, indirectly prevents phagocytosis
LF (lethal factor): Exotoxin that acts as a protease and cleaves map kinase –> tissue necrosis
What is the treatment of Bacillus anthracis?
Fluoroquinolones or doxycycline
How does Bacillus anthracis look under the microscope?
Gram positive rods in chains
Infection with which bacteria is known as “woolsorter’s disease?”
Pulmonar anthrax
How does cutaneous anthrax present?
Black eschar - painless, necrotic
What is the pathogenesis of pulmonary anthrax?
Inhalation of spores –> flu-like symptoms that rapidly progress to fever, pulmonary hemorrhage, mediastinitis, and shock.
Bacillus cereus causes what disease? Which toxin?
Food poisoning; cereulide, a preformed toxin
How does Listeria move inside the cell? Outside the cell?
Inside, actin tails. Outside, tumbling motility.
Who is more likely to get a Listeria infection?
Pregnant women
A Listeria infection in a pregnant woman may lead to what?
Early termination of pregnancy, disease in newborn including meningitis.
How is Listeria infection acquired?
Ingestion of unpasteurized dairy products and deli meats, via transplacental transmission, or by vaginal transmission during birth.
What kind of hemolysis does Listeria exhibit?
Beta hemolysis
How is Listeria treated?
Ampicillin
What is a branching filamentous gram positive anaerobic rod?
Actinomyces israelii
What is a branching filamentous gram positive aerobic rod?
Nocardia
What is the main disease manifestation of Actinomyces?
Cervicofacial actinomycosis
What is the clinical presentation of cervicofacial actinomycosis?
Oral/facial abscesses that drain through sinus tracts. Thick yellow pus due to yellow sulfur granules.
What is the treatment of Actinomyces?
Penicillin G and possibly surgical drainage
Where is Nocardia found?
Soil; does not form spores
What are the possible clinical manifestations of Nocardia?
Pulmonary infections, cutaneous infections after trauma, and CNS infections in the immunocompromised.
What is the treatment of Nocardia?
Sulfonamides
What kind of lung lesions does TB cause?
Fibrocaseous cavitary lesions
What test for TB is more specific than the PPD skin test?
IF-gamma release assay (IGRA) - no false positives from BBG vaccine
What kind of vaccine is the BBG vaccine?
Live-attenuated mycobacterium bovis
What is another name for acid-fast stain?
Ziehl-Neelson
What kind of disease does Mycobacterium avium cause?
Disseminated non-TB disease in AIDS
What is the prophylactic treatment for Mycobacterium avium?
Azithromycin
What are 2 of Mycobacterium TB’s virulence factors?
Cord factor and sulfatides
What is the role of cord factor in TB?
Inhibits macrophage maturation and induces release of TNF-alpha
What is the role of sulfatides in TB?
Inhibit phagolysosomal fusion
What is responsible for the weight loss seen in TB?
TNF-alpha promotes wasting
The lepromatous form of leprosy illicits what kind of immune response?
Th2 - humoral response
The tuberculoid form of leprosy illicits what kind of immune response?
Th1 - cell mediated immunity
What is the treatment for the lepromatous form of leprosy?
Dapsone, rifampin, and clofazamine for 2-5 years!
What is the treatment for the tuberculoid form of leprosy?
Dapsone and rifampin
What are the lactose-fermenting enteric bacteria?
Citrobacter, klebsiella, e coli, enterobacter, serratia
N gonorrhoeae is often intracellular; within what cells?
Neutrophils
Of N gonorrhoeae and N meningiditis, which ferments glucose? Maltose?
Both ferment glucose and only mening ferments maltose
Why is there no vaccine availabe for N gonorrhoeae?
Rapid antigenic variation of pilus proteins
What kind of arthritis can N gonorrhoeae cause?
Monoarticular (usu knee) septic arthritis
What is Fitz-Hugh-Curtis syndrome?
N gonorrhoeae spread into peritoneum
What is the treatment of N gonorrhoeae?
Ceftriaxone + azithromycin for possible chlamydia infection
What is the treatment of N meningiditis?
Ceftriaxone or penicillin G
What is Waterhouse-Friderichsen syndrome?
Hemorrhage of adrenals due to meningococcemia
What is used for prophylaxis in contacts of N mening?
Rifampin
Culturing of H flu on chocolate agar requires which additional growth factors?
Factors V (NAD+) and X (hematin)
What classic diseases does H flu cause in children?
Epiglottitis, meningitis, otitis media, and pneumonia “EMOP”
Describe the H flu vaccine
Type B capsular polysaccharide (polyribosylribitol phosphate) conjugated to diphtheria toxoid
When is the H flu vaccine administered?
Between 2-18 months of age
How is mucosal infection with H flu treated?
Amoxicillin +/- clavulanate
How is H flu meningitis treated?
Ceftriaxone
What is used for prophylaxis in contacts of H flu?
Rifampin
What can labs show in Legionella infection?
Hyponatremia
How is Legionella pneumophilia diagnosed?
Presence of antigen in urine
What is Legionella’s mode of transmission?
Aerosol transmission from environmental water source habitats. No person-to-person transmission.
What is the treatment of Legionella pneumophilia?
Macrolide or quinolone
What kind of pneumonia does Legionnaires’ disease cause?
Atypical patchy pneumonia with consolidation in 1 lobe
How does Legionnaires’ disease present?
Severe atypical pneumonia, ferver > 40 degrees C, GI and CNS symptoms
How does Pontiac fever present?
Mild flu-like symptoms
What is pseudomonas’ color and odor?
Blue-green pigment (pyocyanin) and grape-like odor, or Fritos
Which bug causes malignant otitis externa in diabetics?
Pseudomonas aeruginosa
How does Pseudomonas aeruginosa manifest?
wound and burn infections, Pneumonia (esp in CF), Sepsis, External otitis, UTI, Drug user and Diabetic Osteomyelitis, and hot tub follicultis - “PSEUDOmonas
Which bug causes ecthyma gangrenosm?
Pseudomonas
What is ecthyma grangrenosum?
Rapidly progressive, necrotic cutaneous lesions caused by Pseudomonas bacteremia. Typically in immunocompromised patients.
What is the treatment of infection with Pseudomonas?
Aminoglycoside plus extended-spectrum penicillin (Pip/Taz), or fluoroquinolones
What is the #1 cause of gram-negative nosocomial pneumonia?
Pseudomonas
What is the #1 cause of UTIs?
E coli
What is the #1 cause of gram negative sepsis?
E coli
What are E coli’s virulence factors?
Fimbriae (cystitis and pyelonephritis), K capsule (pneumonia, neonatal meningitis), LPS (septic shock)
What is the presentation of EIEC?
Invasive dystentery
What is the presentation of ETEC?
Travelers’ diarrhea
What is the presentation of EPEC?
Diarrhea usu in children “P for peds”
What is the presentation of EHEC?
Dysentery
What is the most common serotype of EHEC?
O157:H7
Which strain of E coli produces HS and HL enterotoxins?
ETEC
What is the virulence mechanism of EPEC?
No toxin produced. Adheres to apical surface of gut, flattens villi, and prevents absorption.
Is E coli a sorbitol fermenter?
Yes, except for EHEC
A metallic green sheen on EMB agar indicates what bug?
E coli
How is EHEC transmitted?
Eating undercooked meat
Which strain of EHEC produces Shiga-like toxin?
EHEC
What disease processes do Klebsiella, Enterobacter, and Serratia cause?
UTIs and pneumonia
In what setting are Klebsiella, Enterobacter, and Serratia found?
Nosocomial
Klebsiella, Enterobacter, and Serratia cause lobar pneumonia in what patient populations?
Aspiration pneumonia in alcoholics and diabetics
The x-ray of pneumonia caused by Klebsiella, Enterobacter, and Serratia may look like what other disease process?
TB
Of Klebsiella, Enterobacter, and Serratia, which one is urease positive?
Klebsiella
Of Klebsiella, Enterobacter, and Serratia, which one is a lactose fermenter?
All three!
What does it mean to be H2S positive?
Forms black colonies on Hektoen agar plate
Which organisms are H2S positives?
All motile enteric bacteria
Chronic carriers of Salmonella typhi harbor it where?
Gall bladder
What is the #1 cause of osteomyelitis in patients with sickle cell disease?
Salmonella typhi
What is the clinical presentation of Salmonella typhi?
Rose spots on the abdomen, fever, headache, constipation or “pea soup” diarrhea
What is the treatment of Salmonella typhi?
Fluoroquinolone
Which Salmonella species has an available vaccine and what kind of vaccine is it?
S typhi - live attenuated
How does Shigella invade the intestinal mucosa and cause infection?
Passes into lumen of intestine easily (acid-stabile) and invade M cells in Peyer’s patches. Shigella induces M cells to phagocytose them, then Shigella escapes phagolysosome before it’s degraded, and then uses host cell actin to propel itself from cell to cell (similar to Listeria)
Which species of Shigella can cause HUS in children?
Shigella dysenteriae
What is the most common cause of viral encephalitis?
Herpes simplex encephalitis
What is the reservoir for Campylobacter jejuni?
Poultry
Campylobacter can grow at what temperature?
42 degrees Celsius
What are three consequences (besides diarrhea) of Campylobacter infection?
Guillain-Barre, reactive arthritis, and bacteremia
What kind of media does cholera grow in?
Alkaline
What part of the GI tract does Yersinia enterocolitica infect?
Terminal ileum
Which oxidase + curved gram negative rods can cause reactive arthritis?
Campylobacter and Yersinia enterocolitica
Which oxidase + curved gram negative rods can cause bloody diarrhea and abscesses?
Yersinia enterocolitica
Which bacteria has a “safety pin” appearance, meaning it stains bipolar?
Yersinia and Pasteurella
What is the treatment of Yersinia enterocolitica infection?
Streptomycin (with tetracycline)
How is H pylori diagnosed?
Urea breath test or fecal antigen test
How is H pylori treated?
Triple therapy: PPI + clarithromycin + either amoxicillin or metronidazole
H pylori is a risk factor for what?
Peptic and duodenal ulcers, gastric adenocarcinoma, and lymphoma (MALToma)
What is the odor of Proteus?
Fishy
What can Proteus cause?
UTI, struvite staghorn calculi
What is the treatment of Proteus
Sulfonamides
Vibrio vulnificus affects what patient population?
Immunocompromised
How do humans usually acquire Vibrio parahaemolyticus?
Shellfish
What is the clinical presentation of infection with Vibrio parahaemolyticus?
Watery diarrhea, halophilic acute diarrhea, cramps, nausea, vomiting, occasionally bloody stools
Ixodes ticks are involved in transmission of what bugs?
Borrelia, ehrlichiosis, and babesiosis
Heart block, migratory polyarthritis, and bilateral Bell’s paulsy are manifestations of infections with what bug?
Borrelia
What is the treatment for Lyme disease?
Doxycycline and ceftriaxone
What are the clinical manifestations of Leptospirosis?
Flu-like symptoms, jaundice, fever, photophobia with conjunctival suffusion (erythema without exudate)
What is the treatment of Leptospirosis?
Penicillin and tetracycline
Weil disease is the more serious form of what?
Leptospirosis
What is the treatment for syphilis?
Penicillin G
Which bug causes syphilis?
Treponema pallidum
Which bug causes Yaws?
Treponema pertenue
Which bug causes endemic syphilis?
Treponema endemicum
Which bug causes Pinta?
Treponema carateum
How is syphilis diagnosed? First, VDRL/RPR (nonspecific), then a specific test (FTA-Abs)
First, VDRL/RPR (nonspecific), then a specific test (FTA-ABS)
What is the FTA-Ab test?
Test to detect Abs directly against Treponema pallidum
What is the pathogenesis of the painless genital chancres produced by Treponema pallidum?
Locally invades small blood vessels and damages them, which leads to small areas of ischemic necrosis (also takes out nerves - painless)
How does primary syphilis present?
Painless genital chancre, 2-6 weeks after exposure to bug
How does primary syphilis present?
Disseminated disease with constitutional symptoms, maculopapular rash on palms and soles, and condylomata lata
How does tertiary syphilis present?
Gummas (chronic granulomas), aortitis (vasa vasorum destruction), neurosyphilis (tabes dorsalis), Argyll Robertson pupil, borad-based ataxia, positive Romberg, Charcot joint, stroke without hypertension
What are the clinical features of congenital syphilis?
Saber shins, saddle nose, CN VIII deafness, Hutchinson teeth, congenital deafness, and mulberry molars
What is Jarisch-Herxheimer reaction?
Flu-like syndrome after antibiotics are started - due to killed bacteria releasing pyrogens
Warthin-Starry stain (a type of silver stain) is used to visualize what?
Bartonella
Bacillary angiomatosis is caused by what bug? Who does it affect?
Bartonella, immunocompromised
How is Bartonella treated?
Doxycylcine or macrolides
How is one infected with Brucella?
Direct contact with farm animals or ingestion of unpasteurized milk
How is Brucellosis treated?
Doxycycline + rifampin
How is tularemia treated?
Streptomycin
Dog and cat bites typically transmit what bug?
Pasteurella multocida
What are the manifestations of infection with Pasteurella?
Cellulitis and osteomyelitis
What is the treatment for Pasteurella?
Penicillin, or Augmentin
What is the treatment for Gardnerella vaginosis?
Metronidazole
What pH does Gardnerella vaginosis thrive in?
> 4.5
What is the disinfectant mechanism of alcohols? Are they sporicidal?
Disruption of cell membranes, denaturation of proteins; No
What is the disinfectant mechanism of chlorhexidine? Is it sporicidal?
Disruption of cell membranes, coagulation of cytoplasm; No
What is the disinfectant mechanism of hydrogen peroxide? Is it sporicidal?
Produces destructive free radicals that oxidize cellular components; Yes
What is the disinfectant mechanism of iodine? Is it sporicidal?
Halogenation of proteins and nucleic acids; Yes
An “undulating fever,” chills, and anorexia are suggestive of what?
Brucellosis
Which bug causes Q fever?
Coxiella burnetii
Which bug causes Rocky Mountain spotted fever?
Rickettsia rickettsii
Which bug causes endemic typhus?
Rickettsia typhi
Which bug causes epidemic typhus?
Rickettsia prowazekii
Which bug causes psittacosis?
Chalmydophila psittaci
What is the treatment for all Rickettsial disesase?
Doxycycline?
Describe the rash of Rocky Mountain spotted fever
Starts at wrists and ankles then spreads to trunk, palms, and soles. Incubation period of 2-14 days.
Describe the rash of typhus
Starts at trunk and moves towards extremities, sparing hands feet and head
What is the clinical presentation of typhus?
Myalgias, arthralgias, pneumonia, encephalitis, and coma
How does Ehrlichia look under the microscope?
Monocytes with morulae (berry-like inclusions) in cytoplasm
How does Anaplasma look under the microscope?
Granulocytes with morulae in cytoplasm
How is Q fever contracted?
Tick feces and cattle placenta release spores that are inhaled as aerosols
What is the clinical presentation of Q fever?
Fever, cough, headache, hepatitis, no rash
What is the classic cause of walking pneumonia?
Mycoplasma pneumoniae
What is the treatment of Mycoplasma?
Macrolide
Mycoplasma grows on what agar?
Eaton agar
What is the treatment for Chlamydia?
Azithromycin (plus ceftriaxone for gonorrhea co-infection)
Which Chlamydia species and subtype causes chronic infection and blindness?
Chlamydia trachomatis types A B and C
Which Chlamydia species and subtypes cause urethritis, PID, ectopic pregnancy, neonatal pneumonia, and neonatal conjunctivitis?
Chlamydia trachomatis types D-K
Which Chlamydia species and subtype cause Lymphogranuloma venereum?
Chlamydia trachomatis types L1, L2, and L3
How can you differentiate neonatal conjunctivitis caused by Chlamydia vs Gonorrhea?
Neonatal conjunctivitis caused by Chlamydia presents much later