Gram neg/Spirochetes/Mycoplasma Flashcards
(52 cards)
Neisseria meningitides
- Gram - , diplocci (BEAN shaped)
- Encapsulated (LOS** correlates w M and M ~LPS), Maltose and glucose fermenting (meningitides for maltose)
- Vaccine exists (for type A)
- Found in respiratory/oral secretions
- -> Meningococcemia, meningitis (2nd most common children-adults, but # 1 in teens), rash on soles and palms (small vessel vasculitis) Waterhouse-Friderichsen syndrome
- IgA Protease +
- Chocolate agar
-tend to happen in outbreaks in close quarters (think College DORMS!)
Waterhouse-Friderichsen syndrome
<– N. meningitides
- 1) Bilateral adrenal hemorrhage
- 2) DIC
- 3) Shock (hypotension)
- 4) Purple rash
Neisseria gonococci
Gram- DIPLOCCI
-Facultative intracellular: often see in Neutrophils
Only glucose fermenting
-spread by sexual contact
–> gonorrhea, septic arthritis, neonatal conjunctivitis, PID, Fitz-Hugh-Curtis syndrome (Fibrotic Hepatic Capsule syndrome)
-IgA protease+
-Thayer-martin media (choc. sheep blood + ABX - make sure you get rid of all the other bacteria from the vagina swab) = Prostitutes on Thayer Street
-Rx: IM Ceftriaxone + treatment for chlamydia
Think Gonorrhea when you see asymmetric polyarthritis (knees, elbows) in a sexually active young adult
HaEMOPhilus. influenzae
Gram - coccobacillus
- -> Epiglottis* (“cherry red”), Meningitis, Otitis media (nontypeable strains cause mucosal infxns), Pneumonia
- IgA protease (type B is encapsulated)
- Chocolate agar w V, X.
- OR Chocolate agar, S. Aureus, X
- Vaccine: Type B capsular polysaccharide + diptheria toxioid/other . Give to infants! produces anti-PRP** antibodies.
Gram Negative Bacilli/rods
Outer membrane inhibits entry of PCN G and Vancomycin! Resistant!
-May be susceptible to derivatives like Ampicillin and Amoxicillin
Lactose fermenters
Test w macConKEES agar, turn PINK
-on EMB agar turn Purple/black (except E. coli has green sheen)
Citrobacter Klebsiella E. coli Enterobacter Serratia
Legionella pneumonphila
Gram - rod, Lactase -, Oxidase +
- -> Legionnaires’ ds: atypical pneumonia, high fever, Diarrhea, and CNS sxs/confusion; all in a smoker!
- -> Pontiac fever: mild flu-like sxs
- Use Silver stain
- grown on charcoal yeast w iron and cysteine
- HYPONATREMIA, test for antigen in urine
The Legionnaire wears a silver helmet and sits at a charcoal fire w an iron stoker before he decides to charge the Pontiac. He is no Sissy/Cysteine. But he’s chugging a lot of water before he goes so he doesn’t get dehydrated (–> Hyponatremic)
PSEUDOmonas aeruginosa
Gram - rod, Oxidase POS, Aerobe. NON-lactose fermenting.
- -> Pneumonia (CF), Sepsis (black skin lesions/burn pts), Ecythema gangrenosum (pts w neutropenia), UTI (w indwelling cath), Dermatitis (hot-tube users), Otitis externa (swimmers)/Osteomyelitis (Diabetes, IV drug users)
- Produces Pyocyanin* (blue-green) pigment w grape-like odor.
- -> Endotoxin (fever, shock), and Exotoxin A (inactivate EF-2)
E. coli EIEC
Gram - rod, Lactose fermenter, motile -No toxin produced -Microbe invades intestinal mucosa --> necrosis, inflammation ~ clinical pic of Shigella I for INVASIVE, dysentery
Ferments Sorbitol/glucose (vs EHEC) –> gas
Stool: would see many erythrocytes and some leukocytes
E. coli ETEC
Gram - rod, lactose fermenter, motile
-T for Traveler’s diarrhea
LT/ST toxins. No inflammation or invasion
Ferments Sorbitol/glucose (vs EHEC) –> gas
E. Coli EPEC
Gram - rod, lactose fermenter, motile
- P for Pediatrics (diarrhea in children)
- No toxin
- Adheres to apical surface, flattens villi, prevents absorption
Ferments Sorbitol/glucose (vs EHEC) –> gas
E. coli EHEC
Gram - rod, lactose fermenter, motile
-H for Hemorrhagic diarrhea (does not invade the cells*, toxin alone causes necrosis/inflmtn)
-O157:H7 most common type –> SLT –> HUS (TAU - thrombycotpenia, Anemia, Uremia)
(endothelium swells and narrows lumen –> microangiopathic anemia and reduced renal flow. Damaged endothelium consumes plts).
*Does NOT ferment sorbitol or produce glucuronidase.
-Stool: erythrocytes w/o pus (bc not invasive)
FAT RN in kids who ate hamburgers
E. Coli Virulence factors
- Fimbriae –> UTI (#1), cystitis, pyelonephritis
- K capsule (prevents phagocytosis) –>, neonatal meningitis (#2) and neonatal pneumonia (#2) (#1 in both is group b strep)
- LPS endotoxin –> septic shock
Klebsiella
ABCD
Gram - rod, Lactose fermenter
- A: Aspiration pneumonia (DM/ETOHpts)
- B: Burning urine/nosocomial UTI
- C: (red) currant jelly sputum
- D: Donovan bodies (STI called “granuloma inguinale”)
Salmonella typhi
or paratyphi
Gram - rod, Lactose -, Oxidase -
- Flagellate organism, can dissem hematogenously**, animal reservoirs, invades intestinal mucosa –> monocytic response, produce H2S on triple sugar iron (TSI) agar–> black
- antibiotics may prolong sxs*/fecal excretion of bacteria
- Fecal-oral
- multiples in mesenteric LN’s and is phagocytosed by macrophages, lives inside them (facultative intracellular)
- -> Typhoid Fever. Only in humans. ROSE spots on abdomen, fever, HA, diarrhea, abdml pain, HEPATOSPLENOMEGALY –> hemorrhagic enteritis w possible bowel perf. Can remain in GALLBLADDER = carrier state
(common OUTSIDE the States - think of it when someone travels and gets a rash peri-umbilically)
Salmonella and Shigella are SOL: no oxidase OR lactose fermenting
Shigella dysenteriae
Gram - rod, Lactose - , Oxidase -
- Invades intestinal mucosa via M cells and causes PMN infiltration
- ->severe bloody diarrhea (Shiga-Toxin)
- Stool: many erythrocytes and some leukocytes
- Not* carried by animals. Fecal-oral route - daycare center, food contaminated etc
- as few as 10 cells of any shigella spp can cause infection**
Salmonella and Shigella are SOL: no oxidase OR lactose fermenting
Campylobacter jejuni
Gram - , Comma shaped, Oxidase +
- likes the HOT CAMPfire. grows at 42C
- -> diarrhea (activate adenylate cyclase; initially watery –> bloody)
- Fecal oral route by poultry, milk, domestic animals (cattle, sheep, puppies!)
- -> Guillain Barre, Reactive arthritis
- has a filament so it moves in a “corkscrew” fashion
- Most common cause of acute gastroenteritis of children and adults in industrialized countries*
Vibrio cholerae
Gram -, Comma shaped, Oxidase +
- Grows in ALKALINE media
- -> Rice water diarrhea by permanantly activating Gs to incr cAMP
Yersinia enterocolitica
gram - rod, Oxidase -, Lactose -
-transmitted by Puppy Poop and unpasteurized Milk
~ETEC/ST in that it activates guanylate cyclease and incr cGMP
–> Pediatric diarrhea, Mesenteric Adenitis = abdl pain (~ CD or appendicitis)
Yersnia Pestis
Gram-, Lactose-, Oxidase-
Bubonic Plague (swollen LNs)
-sepsis in SouthWestern Rancher exposed to fleas or terrorist attack
-Fleas get it from rats and prairie dogs
Proteus mirabilis
Gram - rod, Lactase -, Oxidase -
- DO have flagella and make H2S (like salmonella) –>black on TSI agar
- Urease Positive (like H. pylori) but prefers GU tract
- -> Staghorn calculi (Struvite Kidney Stones)
H. Pylori
Gram - , comma-shaped.
- Urease+ in GI tract –> Alkaline environment
- RX: PPI, Clarithryomycin, Amoxocillin
Spirochetes
BLT
- Borrelia (BIG!) - visualized w aniline dye (Wright’s or Giemsa) in LM
- Leptospira
- Treponema - visualized by dark-field micro
Mycoplasma pneumoniae
- No cell wall, sterols in plasma membrane (they can get all of us 25 yr olds! and they’re like us: we don’t have cell walls, and we do have cholesterol in our membranes)
- -> atypical “walking” pneumonia (insidious onset, HA, nonproductive cough, diffuse interstital infiltrate), transient anemia
- High titer of COLD AGGLUTININS (IgM) –> agglutinate or lyse rbcs (may see anemia)
- Grows on Eaton’s agar
- most common pneumonia adults 18-40 (everyone older Strep pneumo)
