Bacteriology EC Flashcards
Peptidoglycan Function
Gives rigid support
Protects against osmotic pressure
(What stains on gram stain)
Major surface antigen of Gram+
Lipoteichoic acid (induces TNF/IL-1)
Cell wall (made of peptidoglycan)
Major surface antigen of Gram -
LPS/Endotoxin/Outer membrane
Lipid A induces TNF/IL-1
O polysaccharide is the anitgen
What is the periplasm?
Space between cytoplasmic membrane and outer membrane in gram -
Contains BETA-LACTAMASE
How do beta-lactams work?
Inhibit cross-linking of peptidoglycan by transpeptidase
Gram + Bacteria (gram stain color, major antigen, vulnerability to beta-lactams)
BLUE
Thick cell wall/peptidoglycan (+ is thick)
Lipoteichoic acid
Vulnerable to beta-lactams/lysozymes
Gram - Bacteria (gram stain color, major antigen, vulnerability to beta-lactams)
RED
Thin cell wall/peptidoglycan (- is thin)
LPS (lipid A) Endotoxin
Resistant to beta lactams/lysozymes (beta-lactamase in periplasmic space)
What are the gram + bacteria?
Mycobacterium (acid fast) Gardnerella Staph Strep Corynebacterium Actinomyces Nocardia Bacillus Listeria Clostridium
“My God, Some Silly Corny Actors kNock Back Listerine in the Closet”
What Gram + bacteria commonly cause disease and what is their morphology?
Streptococcus Enterococcus Staphylococcus Bacillus (spore forming) Clostridium (spore forming) Corynebacterium (rods) Listeria (rods)
What are the morphologies of the Gram - bacteria?
Neisseria (diplococcus)
Treponema pallidum (spirochete)
REST=rods/pleomorphic
What stain identifies mycobacterium?
Acid fast (causes TB and leprosy)
What bacteria have unusual cell membranes/walls?
Mycoplasma - STEROLS and NO CELL WALL
Mycobacterium - MYCOLIC ACID and HIGH LIPID CONTENT
What bacteria do not Gram stain well?
Treponema (too thin- use darkfield microscope)
Rickettisa (intracellular)
Mycobacteria (lipid content detected in acid fast stain
Mycoplasma (no cell wall)
Legionella (intracellular)
Chlamydia (intracellular)
“These Rascals May Microscopically Lack Color”
What bugs stain with Giemsa?
Chlamydia Borrelia Rickettsiae Trypanosome Plasmodium
“Certain Bugs Really Try my Patience”
What bugs stain with PAS (periodic acid-Schiff)?
Tropheryma whipplei
(Stains glycogen)
“PAS the sugar”
What bugs stain with Ziehl-Neelsen?
Acid fast
Nocardia
Mycobacterium
What bugs stain with India Ink?
Cryptococcus neoformans
What bugs stain with Silver stain?
Fungi (ie Pneumocystis)
Legionella
H. pylori
What does catalase do?
Breaks down hydrogen peroxide radicals
What does peroxidase do?
Breaks down hydrogen peroxide radicals
What does superoxide dismutase do?
Breaks down superoxide radicals
What are obligate aerobes?
Must use oxygen - same enzymes as us
What are the obligate aerobes?
Nocardia
Pseudomonas
Mycobacterium TB
Bacillus
“Nagging Pests Must Breathe”
What are facultative anaerobes?
Have the faculty to be anaerobic (comparable to skeletal muscle during sprinting)
Prefer O2, but switch if have to
Are obligate anaerobes?
Hate oxygen (no enzymes to defend against it)
What are the obligate anaerobes?
Clostridium
Bacteroides
Actinomyces
“Can’t Breathe Air”
AninOglycosides are ineffective because they require O to enter cell
What bugs are obligate intracellular?
Rickettsia
Chlamydia
(can’t make own ATP)
“stay inside when it gets Really Cold”
What bugs are facultative intracellular?
Salmonella Neisseria Brucella Mycobacterium Listeria Francisella Legionella Yersinia
“Some Nasty Bugs May Live FacultativeLY”
What does the Quellung reaction test for?
Encapsulated bacteria
“Quellung=Swelling”
What bacteria are encapsulated?
E. coli Strep. pneumoniae Klebsiella pneumoniae H. influenzae Neisseria meningitidis Salmonella B Strep
“Even Some Killers Have Nice Shiny Bodies”
What organisms would someone with chronic granulomatous disease get recurrent infections from? Why?
Catalase + organisms Pseudomonas Listeria Aspergillus Candida E. coli S. aureus Serratia
“you need PLACESS for your CATs”
People with CGD have a NADPH oxidase deficiency
Catalase + bacteria neutralize limited H2O2 produced
What bugs are urease +?
Cryptococcus H. pylori Proteus Ureaplasma Nocardia Klebsiella S. epidermidis S. saprophyticus
“CHuck norris hates PUNKSS”
What bacteria produce pigment?
Actinomyces ISRAELii - yellow sulfur granules “Israel has yellow sand”
S. aureus - yellow pigment “aureus=gold’
Pseudomonas AURUGinosa - blue-GREEN pigment “AERUGala is GREEN”
Serratia MARCESCENS - RED pigment “red maraschino cherries”
Corynebacterium diphtheriae (Toxin, Mechanism, Manifestation)
Diptheria toxin
Inactivates EF-2 (elongation factor)
Pseudomembranous pharyngitis
Severe lymphadenopathy ("bull neck")
Pseudomonas aeruginosa (Toxin, Mechanism, Manifestation)
Exotoxin A
Inactivates EF-2 (elongation factor)
Host cell death
Shigella (Toxin, Mechanism, Manifestation)
Shiga toxin
Inactivates 60S ribosome (remove adenine from rRNA)
GI mucosal damage –> dysentery
Cytokine release –> HUS
EHEC O157:H7 (enterohemorrhagic E. coli) (Toxin, Mechanism, Manifestation)
Shiga Like Toxin
Inactivates 60S ribosome (remove adenine from rRNA)
Enhances cytokine release –> HUS
Does no invade host cells
ETEC (enterotoxigenic E. coli) (Toxin, Mechanism, Manifestation)
Heat-LABILE (LT) - overactivates adenylate cyclase, increase cAMP, increase CL and water secretion
Heat-STABLE - overactivates guanylate cyclase, increased cGMP, decreased NaCl and H2O resorption
Watery diarrhea results
“Labile in the Air (Adenylate cyclase)
Stable on the Ground (Guanylate cyclase)”
Bacillus anthracis (Toxin, Mechanism, Manifestation)
Edema factor
Mimics adenylate cyclase (increased cAMP)
Edematous borders of black eschar in cutaneous anthrax
Vibrio cholerae (Toxin, Mechanism, Manifestation)
Cholera toxin
Permanently activates Gs (increased cAMP)
Cl secretion and H2O efflux
“Rice water” diarrhea
Bordetella pertussis (Toxin, Mechanism, Manifestation)
Pertussis toxin
Disables Gi (increased cAMP) Inhibits phagocytosis
Whooping cough
Clostridium tetani (Toxin, Mechanism, Manifestation)
Tatanospasmin
Cleave SNARE and prevent release of GABA/glutamate
Spastic paralysis “Lock jaw”
Clostridium botulinum (Toxin, Mechanism, Manifestation)
Botulinum toxin
Cleave SNARE and prevent release of ACh
Flaccid paralysis “Floppy baby”
Clostridium perfringens (Toxin, Mechanism, Manifestation)
Alpha toxin
Phospholipase that degrades tissue and cell membranes
Myonecrosis (gas gangrene)
Hemolysis (double zone hemolysis)
Streptococcus pyogenes (Group A) (Toxin, Mechanism, Manifestation)
Streptolysin O
Protein that degrades cell membrane
Lyse RBCs (beta-hemolysis)
- host antibodies to streptolysin O (ASO) used to diagnose rheumatic fever*
- Exotoxin A can also cause toxic shock syndrome (superantigen)*
Staphylococcus aureus (Toxin, Mechanism, Manifestation)
TSST-1 (toxic shock syndrome toxin)
Bring MHCII and TCR together without antigen resulting in superantigen with overwhelming release of IFN-gamma and IL-2 –> shock
Toxic shock syndrome (fever, rash, shock)
- Exfoliative toxin causes scalded skin syndrome*
- Enterotoxin causes food poisoning*
Septic shock (Mechanism, Major players, Manifestations)
Endotoxin=LPS found in gram negative bacteria (LIPID A)
Release of LPS from lysis of gram - (or fungi) cause excessive release of TNF and IL-1
Edema NO DIC/Death Outer membrane TNF O-antigen Xtremely heat stable Il-1 Neutrophil chemotaxis
Transformation (what is it?, what bacteria utilize?)
Take up naked DNA
“Take this DNA and be TRANSFORMED”
S. pneumo
H. influenzae
Neisseria
“SHiN”
Conjugation
Bacteria sex (passing plasmids)
F+ uses sex pilus (penis) to transfer DNA to F- (making it F+)
Transposition
DNA that can jump from one location to another
Can jump into plasmid and be transferred to another bacteria
Transduction
Transduced by a bacteriophage (virus)
Generalized (Lytic phage): Phage infects, picks up some DNA, infects another and transfers genes
Specialized (Lysogenic phage): viral DNA incorporates into chromosome, when excised, flanking gene excised with it, other bacteria then infected.
What bacterial toxins genes are encoded for by lysogenic phages (Specialized transduction)?
shigA-like toxin Botulinum toxin Cholera toxin Diptheria toxin Erythrogenic toxin of Strep. pyogenes
“ABCDE”
Determination of coagulase - Staph
NOvobiocin test
Saprophyticus is Resistant
Epidermidis is Sensitive
“on the office STAPH retreat there was NO StRESs”
Determination of alpha hemolytic Strep
Optochin test
Viridans is Resistant
Pneumoniae is Sensitive
“OVRPS” (overpass)
Determination of beta hemolytic Strep
Bacitracin test group B (agalactiae) are Resistant group A (pyogenes) are Sensitive
“B-BRAS”
What are the beta-hemolytic bacteria?
staph. Aureus
strep. Pyogenes
strep. Agalactiae
Listeria
“I have A-PAL who’s beta-hemolytic”
Staphylococcus aureus (Morphology, Virulence, Disease)
Gram + cocci in clusters
(b/c catalase + can form fibrin clot around self leading to abcess)
Protein A binds Fc-IgG (inhibits complement fixation/phagolysis)
Skin infections, Organ abscess, Pneumonia
Toxic shock syndrome, Scalded skin syndrome, Rapid onset food poisoning (toxin mediated)
Acute bacterial endocarditis/osteomyelitis
MRSA (altered penicillin binding protein)
Staphylococcus epidermidis (Morphology, Virulence, Disease)
Gram + Cocci (catalase+, coagulase -)
Biofilms
Prosthetic devices/catheters
Contaminates blood cultures (normal skin flora)
Streptococcus pneumoniae (Morphology, Virulence, Disease)
Gram + cocci (catalase -, alpha hemolytic, optochin sensitive)
Encapsulated IgA protease (allows adherence to mucus membranes)
"MOPS" Meningitis Otitis media Pneumonia Sinusitis
“strep. pneumo MOPS are MOst OPtochin Sensitive”
Viridans strep (Morphology, Virulence, Disease)
Gram + cocci (alpha hemolytic, optochin resistant)
Strep. sanguis=blood (endocarditis-sticks via glyocalyx)
Strep. mutans=dental caries
Strep. pyogenes [group A] (Morphology, Virulence, Disease)
Gram + cocci (beta hemolytic, Bacitracin sensitive)
Pyogenic - pharyngitis, cellulitis, impetigo
Toxigenic - scarlet fever, toxic shock-like syndrome, necrotizing fasciitis
Immunologic-rheumatic fever, acute glomerulonephritis (antibodies to M protein help clear infection but cause)
What are the JONES criteria to diagnose rheumatic fever?
Joints - polyarthritis Heart - endocarditis Nodules - subcutaneous Erythema marginatum Sydenham's chorea
” (s. pyogenes) Pharyngitis can cause PHever and glomerulonePHritis”
Strep. agalactiae [group B] (Morphology, Virulence, Disease)
Gram + cocci, (beta hemolytic, Bacitracin resistant)
CAMP factor (enlarges s. aureus hemolysis)
colonizes vagina
BABIES - pneumonia, meningitis, sepsis
Hippurate test positive
“group B for Babies”
Enterococci (Morphology, Virulence, Disease)
Gram + cocci, (no hemolysis)
E. faecalis, E faecium
Normal colonic flora
UTI, biliary tract infections, endocarditis
VRE (vancomycin-resistant enterococci) important nocosomial
Strep bovis (Morphology, Virulence, Disease)
Gram + cocci (no hemolysis)
Colonizes gut (bacteremia in colon cancer pt’s)
“Bovis in the Blood= Cancer in the Colon”
Corynebacterium diptheriae (Morphology, Virulence, Disease)
Gram +
Exotoxin encoded by beta-prophage
ADP ribosylates EF-2
Pseudomembranous pharyngitis
Lymphadenopathy
Myocarditis (arrhythmia)
Meta-chromatic granules
Elek test for toxin
Clostridium tatani (Morphology, Virulence, Disease)
Gram +, spore forming
Produces TETANOSPASMIN
Cleaves SNARES and inhibits GABA/glycine release
Spastic paralysis
Clostridium botulinum (Morphology, Virulence, Disease)
Gram +, spore forming
Botulinum toxin cleaves SNAREs and inhibits ACh release
Flaccid paralysis (floppy baby)
Clostridium perfringens (Morphology, Virulence, Disease)
Gram +, spore forming
Alpha toxin (lecinthinase)
Myonecrosis (gas gangrene)
“PERFringens PERForates a gangrenous leg”
Clostridium difficile (Morphology, Virulence, Disease)
Gram +, spore forming
Toxin A (enterotoxin) - binds brush border
Toxin B (cytotoxin) - destroys cytoskeleton of enterocytes PSEUDOMEMBRANOUS COLITIS (often secondary to clindamycin or ampicillin)
treat w/ metronidazole or vancomycin
Bacillus anthracis (Morphology, Virulence, Disease)
Gram +, Spore forming
(Only bacteria with polypeptide capsule)
Lethal factor/Edema factor - Cutaneous anthrax - black eschar
Inhalation of spores - flu-like progress to fever, pulmonary hemorrhage, mediastinitis, and shock
(Woolsorter’s disease - inhalation of spores in contaminated wool)
Bacillus cereus (Morphology, Virulence, Disease)
Gram +
Reheated rice - spores germinate and produce enterotoxin (cereulide)
Diarrhea
Listeria monocytogenes (Morphology, Virulence, Disease)
Gram + intracellular
Ingestion of unpasteurized milk/deli meat
“ACTIN ROCKETS”/tumbling motility
Amnionitis, Septicemia, Spontaneous abortion
Granulomatosis infantiseptica, Neonatal/Immunocompromised meningitis,
Actinomyces (Morphology, Virulence, Disease)
Gram + Long branching filaments (look like fungi)
Normal oral flora
Cause abscess that drain through sinus tract forming ‘SULFUR GRANULES”
Nocardia (Morphology, Virulence, Disease)
Gram +, long branching filaments (look like fungi)
Found in soil
Immunocompromised - pulmonary infections
Immunocompetent - skin infection after trauma
Mycobacterium tuberculosis
ACID FAST
Primary - Gohn complex in mid lung
Secondary - Caseating granuloma in upper lung (reactivation)
Extrapulmonary: CNS (parenchymal tuberculoma or meningitis) Pott's disease (vertebral body) Lymphadenitis Renal GI
PPD skin test - in sarcoidosis, immunocompromised, BCG vaccine
TB symptoms
Fever
Night sweats
Weight loss
Hemoptysis
Mycobacterium avium
ACID FAST
Disseminated disease in AIDS
prophylaxis with AZITHROMYCIN
Mycobacterium leprae
ACID FAST
Infects skin and superficial nerves “glove and stockings”
Armadillos - reservoir
Lepromatous - Skin (contagious)
Low cell mediated immunity - Humoral TH2 response
Tuberculoid - few skin plaques
High cell mediated immunity - TH1 response
Treat with DAPSONE + RIFAMPIN + CLOFAZIMINE
Neisseria gonorrhoeae
Gram - diplococci
Produce IgA protease
Ferments glucose (not maltose)
Gonorrhea Septic arthritis Neonatal conjunctivitis PID Fitz-Hugh-Curtis syndrome (post PID adhesions to liver)
Neisseria meningitidis
Gram - diplococci
Produce IgA protease
Ferments glucose AND maltose
Meningitis
Waterhouse-Friderichsen syndrome (bleed into adrenal glands)
Haemophilus influenzae
haEMOPhilus (usually vaccinated against)
Epiglotitis (cherry red children)
Meningitis
Otitis media
Pneumonia
Culture of chocolate agar (requires factor V and X)
Legionella pneumophila
(lover water)
Legionnaire’s disease - pneumonia, fever, GI, CNS
Pontiac fever - flu-like
Use SILVER STAIN, grow on CHARCOAL yeast culture with IRON and CYSTINE
“French Legionnaire with his SILVER helmet around a campfire (CHARCOAL) with his IRON dagger. He’s no sissy (CYSTEIN)”
Pseudomonas aeruginosa
PSEUDOmonas (loves water)
Pneumonia Sepsis External otitis UTI Diabetic osteomyelitis
Produces green/blue pigment w/ grapelike odor
EIEC
INVASIVE
No toxins
Bloody diarrhea
ETEC
TRAVELER’S DIARRHEA
Heat labile (cAMP)/stabile toxin (cGMP)
Watery diarrhea
EPEC
PEDS
Adheres and interfere’s with absorption
EHEC O157:H7
HEMOLYTIC UREMIA SYNDROME (anemia, thrombocytopenia, acute renal failure)
Shiga-like toxin (inactivates 60S ribosome)
Klebsiella
Intestinal flora
Lobar pneumonia in alcoholics and diabetics when aspirated
“Currant jelly sputum” - very mucoid w/ polysaccaride capsule
Salmonella typhi
Spreads hematogenously
Invades and produces bloody diarrhea
TYPHOID FEVER (remain in gallbladder as carrier) red spots on abdomen fever headache diarrhea
Shigella
Produces shiga toxin - diarrhea
Spreads cell to cell
Campylobacter jejuni
Bloody diarrhea in children
Fecal oral through foods
Can cause Guillain-barre and Reactive arthritis
Vibrio cholerae
RICE WATER DIARRHEA
Cholera toxin permanently activates Gs
Yersinia enterocolitica
Pet feces (dog)
Mesenteric adenitis
can mimic Chrohn’s or appendicitis
Helicobacter pylori
Risk for PUD, gastric adenocarcinoma, lymphoma
Urease +
What are the common spirochetes?
BLT
Borrelia
Leptospira
Treponema
Leptospira interrogans
Water contaminated with animal urine
LEPTOSPIROSIS: flu, jaundice, photophobia,
SURFERS
Weil’s disease - jaundice, liver and kidney dysfunction, fever, hemorrhage, anemia
Borrelia burgdorferi
Lyme disease
Ixodes tick
Erythema chronicum migrans Neurologic (Bell's palsy) Cardiac (AV node involvement) Musculoskeletal CNS
Treponema pallidum
SYPHILIS (detected with VDRL)
Primary- painless chancre
Secondary - Rash on palms and soles, Codylomata lata
Tertiary - Gummas, Neurosyphilis (tabes dorsalis)
Argyll Robertson pupil - constricts to accommodate but unreactive to light
Congenital syphilis
Saber shins Saddle nose CN VIII deafness Hutchinson's teeth Mulberry molars
Jarisch-Herxheimer reaction
Flu-like syndrome after antibiotics are started in syphilis infection (due to lysed bacteria)
Gardnerella vaginalis
Vaginosis
“Fishy smelling” gray vaginal discharge
Clue cells
Rickettsia rickettsii
Rocky Mountain spotted fever (tick bourne)
Starts on WRISTS AND ANKLES
Spreads to TRUNK, PALMS AND SOLES
Rickettsia prowazekii
tick borne (like RMSF)
Starts on TRUNK (spares palms and soles)
What infections produce a rash on the palms and soles?
“you drive CARS using your palms and soles”
Coxsackievirus A (hand, foot, and mouth)
Rocky mountain spotted fever
Syphilis
Chlamydiae trachomatis
Elementary body Enters cell by Endocytosis
Reticulate body Replicates
Types A-C: Conjunctivitis/Blindness (#1 cause)
Types D-K: Urethritis, PID, neonatal pneumonia (staccato cough)
Reactive arthritis
Chlamydiae pneumoniae
Causes atypical pneumonia
Mycoplasm pneumoniae
Atypical “walking” pneumonia
HEADACHE
NONPRODUCTIVE COUGH
DIFFUSE INTERSTITIAL INFILTRATE
Cold agglutinins (IgM)
Outbreaks in military recruits and prisons
