Gram negative bacteria disease

Question 1

Lactose fermenting enterics

Answer 1

Grow pink colonies on MacConkey’s agar (Lactose is KEE)

Citrobacter, klebsiella, E Coli, enterobacter and serratia
“Test MacConKEE’S agar”

EMB agar: lactose fermenters grow as purple/black
Ecoli grows purple colonies with a green sheen.

Question 2

Penicillin and gram negative bugs

Answer 2

Gram negatives are resistant to penicillin G but may be susceptible to penicillin derivatives, such as ampicllin and amoxicillin

Question 3

Neisseria

Answer 3

Gonococcis: no capsule, gonorrhea, septis arthritis, neonatal conjunctivitis, PID and Fitz Hugh Curtis syndrome, treat with ceftriaxone and azithro/or doxy

Meningococcus: capsule, maltose fermenter, vaccine but not for type B, Waterhouse-Friderichsen syndrome, prophylaxis with rifampin, cipro, ceftriaxone in close contact, treat with penicillin G or cetriaxone

Question 4

H influenza

Answer 4

HaEMOPhilus: epiglottitis, menigitis, otitis media, and pneumo.

Produce IgA protease
Culture chocolate with V and X, can be grown with S aureus, which provides factor V.

Treat meningitis with ceftrixaone,
Rifampin prophylaxis in close contact.

Vaccine contains B capsular polysaccharide t diphtheria toxoid.

Question 5

Legionella pneumophilia

Answer 5

Legionanire’s disease:severe pneumon, fever, GI, and CNS

Pontiac fever: mild flu like syndrome

Gram negative rod: gram stains poorly: use SILER
Grow on charcoal yeast with iron and cysteine.

Detect urine atnigen.

Treat with macrolides or quinolone

???Lab shows hyponatremia

Question 6

Pseudomonas

Answer 6

PSEUDOmonas: pneumo(in CF), sepsos (black lesions on skin), external otitis (swimmer’s year), UTI, Drg use and diabetic osteomyelitis and hot tube folliculitis

Aerobic gram negative rod, non lactose fermentaing, oxidase positive.

Produces endotoxin (fever, shock), and exotoxin A (inactivates EF2)

Treat with aminoglycoside plus extended penicillin (piperacillin, ticarcillin)

Think pseudomonas in BURNT victims.
AERuginosa: AEROBIC and ARUGLULA (green)

Question 7

E coli virulence factors

Answer 7

E coli virulence factors:
Fimbriae: cystitis and pyelonephritis
K capsule: pneumonia, neonatal meningitis
LPS endotoxin: septic shock

Question 8

E coli strains

Answer 8

EIEC: invade intestinal mucosa and causes necrosis and inflam. NO toxin produced. Clinically similar to Shigella. “Invading dysentery”

ETEC: labile toxin/stable toxin. No infmallation or invasion “traveler’s diarrhea”

EPEC: no toxin, adhere to apical surface, flattens villi, prevents absoprtion. “diarrhea usually in Pediatrics”

EHEC: O157:H7 the most common serotype, produces SLT and HUS syndrome (anemia, throbocytopenia, acute renal failure), endothelium swells and narrows lumen, leading to mechanical hemolysis and reduced renal blood flow, damage endothelium consumes platelets. Dysentery (toxin alone causes necrosis and inflammation). DOES NOT FERMENT SORBITAL (distinguishes from other E coli)

Question 9

Klebsiella

Answer 9

Lobar pneumo in alcoholic and diabets when aspirated

Very mucoid coloniescaused by abundant polysaccharide capsules: RED currant jelly. Also nosocomial UTI

4As: aspiration pneymo, abscesses in lungs/liver, alcoholics, diAbetics

Question 10

Salmonella vs shigella

Answer 10

Salmonella: flagella (salmon swim), disseminate hematogenously, animal reservoirs, produce hydrogen sulfide, antibiotics may prolong symptoms, invade musoca and causes MONOCYTIC response (intracellular), can cause bloody diarreha

Shigella: no flagella, cell to cell transmission, no hematogenous spread. Only reserve in humans and primates, does NOT produce hydrogen sulfide, antibiotics prolong excretion of organisms in feces, invades musoca and causes PMN response (extracellular), OFTEN cause bloody diarrhea.

Both do NOT ferment lactose and oxidase negative.

Salmonella typhi: causes typhoid fever, only in humans, red spots on the abd, fever, headache, diarrhea. Can remain in gallbladder and cause a carrier state.

Question 11

Campylobacter jejuni

Answer 11

Major cause of bloody diarrhea, esp in children.

Fecal-oral transmission through foods such as poultry, meant, unpasteurizing milk

Comma shaped, oxidase positive, grows at 42C
“campy likes the hot camp fire”

Antecedent to Guillian Barre syndrome and reactive arthritis.

Question 12

Vibro cholerae

Answer 12

Rice water stool due to Gs activation
Comma shaped oxidase positve, grows in alkine media

Endemic to developing countries, prompt rehydration is necessary.

Question 13

Yersinia enterocoliti

Answer 13

Transmitted from pet feces (puppies), contaminated milk, or pork.

Causes mesenteric adenitis that can mimic CROHN’s or appendicitis.

Question 14

H pylori

Answer 14

Gastritis and 90% of duodenal ulcers
Curved gram negative rod
Ureas positive
Creates alkaline environment
Most common initial tx: PPI, clarithromycin, amoxicillin or metronidazole.

Question 15

Spirochetes

Answer 15

BLT: borrelia, leptospira, treponema

Borrelia is BIG; can be visualized by aniline dyes (Wrights or Giemsa) in light.

Treponema visualized by dark-field.

Question 16

Leptospira interoggans

Answer 16

Found in water contamined with ANIMAL URINE.
Causes leptospirosis: flu like, jaundice, photophobia, with conjunctivitis.

Prevalent in surfers in tropics “Hawaiian surfers who touch animal urine”

***Weil’s disease: icterohemorrhagic heptospirosis: severe form with jaundice and azetemia from liver and kidney dysfunction; fever, hemorrhage and anemia.

Question 17

Lyme disease

Answer 17

Burrelia burgdorferi, transmitted by tick Ixodes (also vector for Babesia).

Natural reservor in mouse.
Common in northeastern US
Treat with doxi or ceftriaxone

3 stages:

1) erythma chronicum migran: bulls eye, flu like
2) neurologi: facial nerve palsy, and cardiac (AV nodal block)
3) MSK (chronic monarthritis and migratory polyarthritis), neurologic (encephalopathy and polyneuropathy) and cutaneous manifestations.

FAKE a key LYME pie:
Facial nerve palsy; typically bilateral
Arthritis
Kardiac block
Erythema migrans

Question 18

Syphilis

Answer 18

1’ painless chancre, screen with VDRL and confirm with FTA-ABS

2’ secondary=systemic, disseminated with constitutional sympts, maculopapular rash (palms and soles), condylomata lata. scree with VDRL and confirm with FTA-ABS

3’ Gummas (chronic granulomas), aoritis (vsava vasorum destruction), neurosyphilis (tabes dorsalis), argyll Roberson
Signs: broad based ataxia, positive rombergs, charcot joint, stroke withy HTN. Test spinal fluid with VDRL.

Congenital syphilis: saber shins, saddle nose, CN VIII deafness, Hutchinson’s teeth, mulberry molars.

Question 19

Argyll Robertson pupil

Answer 19

Argyll Robertson pupil constriction with accomondation but not reactive to light; 3’ syphilis.

Prostitute’s pupil: accomondates but does not react

Question 20

VDRL false positives

Answer 20

Non specific antibodies that react with beef cardiolipin

Viral infections(mono, hepatitis), some drugs, rhumatic fevers, SLE and leprosy

VDRL: virus, drugs, rhuematic, lupus/leprosy

Question 21

Jarisch-Herxheimer reaction

Answer 21

Flu like symptom immediately after Abx started

due to killed bacteria release pyrogens.

Question 22

Rickettsia and vector born illness

Rash producing

Answer 22

All treat with doxy

Rash producing:
Rocky Mountain spotted fever (tick): Rickettsia rickettsii, broadly distributed in US. Rash typically start at wrists and ankles and then spread to trunk, palms, and soles.

Richettsiae are obligate intracellular with need CoA and NAD+

Typus:
endemic (fleas) - R thyphi
epidemic (human body rouse) = R prowazekii, rash starts CENTRALLY and spreads out, sparing palms and soles.

Classic triad: headache, fever, rash
“Rickettsiii starts on wRist, Typhus on the Trunk”

Palms and sole rashes in Coxaskies A (HFM disease), Rocky mountain spotted fever, and Secondary syphilis
“You drive CARS using your palms and soles”

Question 23

Rickettsia and vector born illness

No rash producing

Answer 23

All treat with doxy

Ehrlichiosis (tick): monocytes with morula (berry like inclusions) in cytoplasm
Anaplasmosis (tick): granunocytes with morula in cytoplasm

Q fever (tick feces and cattle placenta release that are inhaited as aerosols)- Coxiella brunetii: no arthropod vector, presents as pneumonia.
"Q fever is Queer because no rash or fever, and its causative organism can survive outside its endospore form. In in the Rickettsia genus but closely related"

Question 24

Chlamydia

Answer 24

Elementary body (small, dense), is Enfectious and Enters cells via Endocytosis

Reticular body Replicates in cell by fission; form seen on tissue culture.

C trachomatis: reactive arthritis, conjunctivitis, nongonococcal urethritis, PID
C pneumoniae and C psittaci: cause atypical pneumonia, transmitted by aerosol. C psittaci notable for an avian reservoir.

Lab dx: cytoplasmic inclusion seen on Giemsa or fluorescent AB stained smear.

Chylamidial cell wall unusual in that it lacks muramic acid

Treatment: azithro or doxy

Question 25

C trachomatis serotypes

Answer 25

Types ABC: chronic infection, blindness due to follicular conjunctivitis in Africa “ABC=Africa/Blindness/Chronic infection).

Type D-K: urethritis, PID, ectopic pregn, neonatal pneumo, or neontal conjunctivitis. D-K everything else, Neonatal disease can br acquired during passage through infected birth canal

Type L1,2,3: lymphogranuloma venereum: painful lymph node.

Question 26

Mycoplasma pneumonia

Answer 26

Atypical walking pneumonia: insidious onset, headache, nonproductive cough, diffuse interstitial infiltrate.

Xray looks worse than pts. High IgM, cold agglutinins, which agglutinate or lyse RBS

Grow on Eaton's agar
No cell wall, not seen in Gram stain
Contains sterol for stability
More common in younger pts <30 yrs
Frequent outbreaks in military recruits and prison

Treat with macrolide or fluoroquinolon.

Question 27

Gardnerella vaginalis

Answer 27

Pleomorphic gram variable rods that cause vaginosis presenting as gray vaginal discharge with a fishy smell

Associated with sexual activity but no STD
Clue cells, or vaginal epithelial cells covered with bacteria

Treat with metronidazole

“I dont have a clue why I smell fish in the vagina garden”