GI tract Pathogens Flashcards

Question 1

Q

Dental Plaque (Strep Viridans)

Answer

A

Gram (+) cocci & catalase (-)-NO cap
Alpha hemolytic NO Lancefield Ag
Optochin resistant
Found in normal flora:
_^Mouth
_{^{Upper resp tract}}
_{^{Intestinal tract}}
High risk:
_{^{Poor mouth hygiene}}
_{^{Tooth extraction}}
_{^{Oral surgery/Trauma}}
_{^{Enter blood (bacteremia)}}
- _{^{Endocarditis=abnormal heart valve}}
Virulence factors: No toxins
Adherence & formation of biofilm
Makes dextrans/levans _{^{(large polysacs)}} from sucrose_{^{-enhances attachment}}
_{^{Production of acid from sugars}}
_{^{Lower PH=Mineralization of enamel}}

Question 2

Q

Dental Plaque (Strep Viridans)-Clinical

Answer

A

Disease:
Dental cavities
Gingivitis
Periodontitis
- _{^{Strep is initiating organism>once plaque becomes polymicrobal}}
Subacute endocarditis:
After beacteremia
Settles on heart valves _{^{(precondition more susceptable)}}
- _{^{vegetation forms}}
- _{^{Made of fibrin bacteria, inflamm cells}}
_{^{Osler node}}
_{^{Janeway lesions}}
_{^{Petechiae in EYE}}
_{^{Splinter hemorrhages (nail bed)}}
Treat: Penicillin (increasing resistance)

Question 3

Q

Mumps (Paramyxoviridae)

Answer

A

Enveloped (-) ssRNA
H & N spikes
F peplomer=Fusion
Helical necleocapsid w/Pleomorphic envelope_{^{(RNA dep/RNA poly)}}
Affects salivary glands:
- _^Sublingual
- _{^{Parotid (largest)}}
- _{^{Submandibular}}
High risk:_{^{Unvaccinated children (winter/spring)}}
Infection starts in resp tract>enters blood…
1st systemic site of infection=_{^{Parotid gland}}
- _{^{Multiplies in ductal epi cells>Swelling w/pain}}
secondary sites=Testes, ovaries, CNS, & pancreas _{^{(juvenile diabetes)}}

Question 4

Q

Mumps (Paramyxoviridae)-Clinical

Answer

A

Contagious 7 days prior to onset of symptoms
Transplacental infection
Prodormal=Fever, malase, anorexia
Parotitis=Swelling of all or ONE of salivary glands (unilateral or bi)
- _{^{gone w/in 1 week}}
Orchitis=Inflammation of testes (post-pubertal)
- _{^{painful & can present bilateral=Sterility}}
- _{^{Due to fiborous Tunica Albuginea}}
Oophoritis=Inflammation of ovaries
- _{^{Mimic appendicites w/Rt ovary}}
Meningitis or Ecephalitis _^(CNS)
Pancreatitis_{^{(Juvenile diabetes)}}
Treat: No antiviral drugs
_{^{Vaccine=Live attenuated MMR/MMRV w/2 doses}}

Question 5

Q

Peptic Ulcers (H. Pylori)

Answer

A

Gram (-) curved rod/spiral HIGHLY motile
Urease (+) catalase & oxidase (+)
Life long colonization if NOT treated
Spread through oral-fecal route
Virulence factors:
Mucinase-^{_{Enzyme hydrolyzes mucopolysac substances (mucins)}}
Phospholipases-_{^{Hydrolyze phospholipids}}
- _{^{Urease-Breaks urea to Co2/NH3=Neutralize gastric acid}}
_{^{Vacuolating cytotoxin A}}-_{^{Damage epi cells w/vacuoles}}
_{^{Cytotoxin assoc gene}}-_{^{Destroy epi cell cytoskelton}}
- _{^{Type 4 secretion-"Inject" CagA to epicells}}
- _{^{Cag+ = Gastroadenocarcinoma}}
_{^{LPS-Inflammatory response (PMN/Mononuclear cells)}}
_{^{Further destruction done internally by digestive enzymes/acid}}
- Ulcer formed

Question 6

Q

H. Pylori-Clinical

Answer

A

Chornic conditions:
Lymphoproliferative disease-Malt B-cell lymphoma
Atrophic gastritis>Gastric adenocarcinoma
- _{^{Assoc w/Cag+ strains}}
Presents:
- _{^{Upper ab pain}}
- _{^{Feeling full}}
- _^Nausea
- _{^{Bleeding into Gi tract}}
Diagnose:
Urease breath test-Ingest radioactive urea
- _{^{Detects radioactive CO2 in breath}}
_Treat: _
- _{^{PPI (omeprazole)}}
- _{^{Macrolides (clarithromycin)}}
- _{^{Beta-lactam (amoxicillin)}}
- _{^{Metronidazole}}

Question 7

Q

Enteric Infections (Diarrhea)

Answer

A

Proximal Small intestine _{^{(non-Inflammatory)}}^_:
_{^{Watery diarrhea &+/- vomit w/Superficial invasion}}
_{^{Pathogen alter water/electrolyte movement}}
_{^{Larger vol of feces w/NO leukocytes}}
_{^{Ex. E. coli, Viral, Protozoas}}
Distal SI or Colon_{^{(inflammatory)}}:
_{^{Dysentery (blood),diarrhea}}
_{^{Cytotoxins, superficial ulceration w/gut cell destruction}}
_{^{Small vol of feces w/Leukocytes}}
_{^{Ex. Shigella, entamoeba, C. difficle}}
Distal SI or Colon:
_{^{Systemic penetration (Blood>lymph) with or w/o dysentery}}
_{^{Small vol of feces w/Leukocytes}}
_{^{Ex. Salmonella, Yersinia}}
Diagnosis: Important to know frequency/volume of feces
- _{^{3+ in a 24 hr period=Diarrhea}}

Question 8

Q

Staph Aureus (GI)

Answer

A

Gram (+) cocci, Catalase/Coagulase (+)
- _{^{Growth @ 7.5 NaCl}}
_{^{Found in nose, skin, LOW lvls in colon/vagina}}
Consumption of contaminated foods-
_{^{Food handler (picks nose)}}
_{^{Grows better on Carb & protein rich foods}}
_{^{Ex. Custards, potato-egg salad, processed meat}}
_{^{High risk in warmer months w/foods not refrigerated}}
Diagnose: Detect on food or in vomit
Self-limiting (24-40 hrs) w/rehydration
Virulence factors-Non-infectious w/8 serotypes
_{^{Heat stable @ 100c for 30 min}}
_{^{Resitant to gastric acid (ingesting toxin)}}
_{^{Emetic activity(cereulide)=Stims vagus nerve in stomach lining (vomit)}}
_{^{SuperAg activity=Stims T-cell proliferation=Release of TNFa/IFNy into BS}}
Sudden onset less than an HOUR

Question 9

Q

Bacillus Cereus (GI)

Answer

A

Gram (+) spore forming rod-Aerobic
_{^{Consumption of contaminated cooked food w/soil}}
- _{^{Rice, grains, root vegetables}}
High risk: _{^{Heat resistant endospores germinate/multiply on food inadequately refrigerated}}
Clinical: 2 types of food poisoning
Emetic (strict intox)-ingestion of pre-formed heat stable toxin
_{^{Carb rich food (boiled rice/pasta) held @ ambient temp too long}}
_{^{Enterotoxin superAg=Cereulide-stims vagus nerve (vomit)}}
_{^{Rapid onset 1-6 hrs symptoms 24 hrs}}
_{^{PROFUSE vomiting w/NO fever or diarrhea}}
Diarrheal (infection/intox)-ingestion of organism & production of heat-labile toxin
_{^{Stimulates cAMP-GI fluid secretion=Diarrhea}}
_{^{Protein rich foods Or vegatable dishes, pudding, milk}}
_{^{Slower onset 6-16 hrs}}
_{^{Watery diarrhea, vomiting, cramps}}

Question 10

Q

Bacillus Cereus-Other infections

Answer

A

GI-
Diagnose: Toxin in stool or food
Treat: self-limiting w/hydration
Other infections:
Eye infection:
Severe keratitis _{^{(inflammation of cornea w/scar)}}
endophthalmitis_{^{(inflammatory cond of inner eye)}}
panophthalmitis _{^{(inflammation of enire eye)}}
High risk: eye trauma, non-sterile contact lens sol OR IV drug users
Rapid progression-12-48 hrs of injury
Loss of sight in 2 days
Treat w/multiple antibios or surgery to remove affected eye

Question 11

Q

Clostridium Botulinum (GI)-General

Answer

A

Gram (+) spore formiing rods-_{^{Strict anarerobe}}
Tennis racket appearance
Strict Anaerobe (NO o2)
Found in Colon flora or in neutral/alkaline soil
Transmission:
_{^{Ingestion of preformed toxin}}
_{^{Trauma & wound infection}}
_High risk: _
_{^{Canned foods (Homemade)}}
_{^{Fermented fish (Alaska)}}
_{^{Improperly sterilized commercial canned alkaline veges (green beans, peppers,mushrooms)}}
_{^{IV-black tar heroin}}
_{^{Infants less than 1 year old w/honey (inhalation common)}}
_{^{Prison wine outbreak}}

Question 12

Q

Clostridium Botulinum (GI)-Disease

Answer

A

Produces invasive enzymes: Lipases, gelatinase _{^{(lead wound infection)}}
Neurotoxin-_{^{8 different serotypes}} _{^{(A,B,E common)}}
Carried by phage _{^{(Bacterial virus)}}:
_{^{Highly potent-letal dose 1-2ug/kg}}
_{^{Type A/B associated w/canned foods}}
_{^{Type E associated w/Fish}}
_{^{Absorbed in gut>blood stream}}
_{^{Binds @ pre-synaptic neuron>cleaves protein involved w/release of Ach}}_{^{_⁽exotoxin)}}
- _{^{SNARE proteins (synaptobrevin/Syntaxin)}}
- _{^{Causes bilateral flaccid paralysis}}
Food borne (Intoxication)-
_{^{Heat Libile dead after 10 min}}
_{^{Incubation 18-72 hrs after ingest}}
_{^{Recovery months to years}}
_{^{Presents w/ab pain (diarrhea or constipation) untreated bilateral DESCENDING paralysis}}
Wound (infection)-_{^{Incubation 1-4 days symptoms similar to food borne (Black-tar heroine)}}
_{^{Dry-Furrowed tongue}}

Question 13

Q

Clostridium Botulinum (GI)-Clinical

Answer

A

Infant botulism: “floppy baby”
_{^{Most common in US}}
_{^{Incubation=3-30 days}}
_{^{Ingestion of spore and germinates in GI due to low flora(multiply in gut-make toxin) absorbed in blood}}
_{^{Associated w/Honey & dust inhalation}}
_{^{Symptoms: Lethargy, constipation, poor feeding (sucking reflex), Facial paralysis}}
Diagnosis: Toxin in pt’s blood/Infant’s stool
Treat: Antiobios=Wound _{^{(not infants could worsen)}}
- _{^{Passive immunization ANTI-toxin (A,B,E)}}
- _{^{Anti-bios NOT used in Infants due to worsening the condition (killing flora)}}
Prevention: Heating canned foods

Question 14

Q

Clostridium Perfringens (GI)-General

Answer

A

Enterotoxin NOT Gangrene
Gram (+) spore forming rod-Type A _^(anaerobic)
Found in normal GI_{^{(large intestine)}}
Transmission: Ingestion of large # of bacteria grown on pre-cooked meats _{^{(not refrigerated)}}
Gravy, Meats, poultry
Food poisoning (toxin/infection):
HIGH dose 10⁸ to 10⁹ of bacteria needed=_{^{small intestine}}
- _{^{Enterotoxin-Heat liable (B.cereus) Increase cAMP=Watery diarrhea}}
- _{^{Increases intracellular Ca+2 alters membrane perm=Loss of fluids/macomols}}
Incubation: 8-16 hours will last 24 hours in immunocomprimised 1-2 weeks

Question 15

Q

Enterobacteriaceae (GI)-Non/inflammatory

Answer

A

All Gram (-) non-spore bacilli
Faculative anaerobes=Ferment glucose
Oxidase (-) Reduce Nitrates>Nitrites _^(UTI)
_{^{Class based on tests (carb fermentation & AA decarboxylase) & antigenic prop of O-Ag (LPS)}}
MacConkey & Eosin methylene blue agar for Lactose fermentation:
- ^{_{Low pH = Pink in MAC}}
- ^{_{Gram (-) ONLY}}
TSI: Contains 3 sugars _{^{(glucose, sucrose, lactose)}}
- _{^{Lactose & Sucrose=Large amount of acid}}
- _{^{Glucose=Less amount of acid}}
- _{^{Contains Ferrous sulfate (black)}}
OKH Ag serotypping:
_{^{O terminal sugar used to ID different strains}}
- ^{_{A core endotoxin common in all}}
_{^{K (capsular) virulence Ag}}
_{^{H flagellar found on motile strains}}

Question 16

Q

E. Coli (GI)-General

Answer

A

5 groups classified by virulence factor
Non-inflammatory _{^{(Small intestine-lumen)}}
_{^{Enterotoxigenic (ETEC): travelers & infants in developing countries=Watery diarrhea & nausea}}
_{^{Enteropathogenic (EPEC) & Enteroaggregative (EAEC): Childhood diarrhea}}
_{^{Gram (-) Rod=Lactose fermenter}}
_{^{Most common bacilli in GI tract}}
_Virulence factor: _
Exotoxins-
_{^{Heat stable toxin (ST)-Excess cGMP=Blocks ion transport INTO cells>water moves into LUMEN}}
_{^{Heat liable toxin (LT)-similar to cholera toxin}}
_{^{binds to GM1 ganglioside receptors on Gut>Increase cAMP outflow of Cl-=Inihibition of Na+ absorption}}
_{^{Ion imbalance=Water loss=Diarrhea}}
_{^{Shiga like toxin (STx)}}
Adhesion-
_{^{Colonizing factor adhesions (CFA)-Fimbriae recognize host glycoprotein receptor}}
_{^{bundle forming pili (Bfp)}}
_{^{adherance fimbriae (AAF)}}

Question 17

Q

EAEC-Enteroaggregative (GI)

Answer

A

Aggregative adherence fimbriae (AAF):
^{_{Bacterial clumping into small aggregates}}
^{_{Stacked bricks-Bacteria parallel rows (autoagglutination)}}
_{^{Stimulates mucus production-Mucus + Bacterial aggregates = Biofilm}}
_{^{Biofilm>ST toxin (heat stable)=Excess cGMP interferes w/ ion absorption}}
^{_{Cytotoxin/hemolysin=Shortening of microvilli>Decreased fluid absorption}}
Disease: Presistant watery diarrhea w/vomiting & dehydration NO fever
Lasts 14 + days
- _{^{Infantile chronic diarrhea=Growth retardation}}
- _{^{Travelers’ diarrhea in HIV pts}}

Question 18

Q

EPEC-Enteropathogenic (GI)

Answer

A

Virulence factors:
Bundle forming pili (Bfp)-patchy adherence>Tir insertion & intimin binding
_{^{Attaching>effacing=Destruction of microvilli}}
_{^{Forms cup-like pedestal structure in cytoplasm made of Cytokeretin 18 =dense mat of actin fiber under EPEC (attaches to apical membrane)}}
_{^{TYpe 3 injection system (Tir) allows for attachment and eventual Destruction of microvilli=Malabsorption=Diarrhea}}
Disease: “Infantile diarrhea”
Epidemics in newborn nurseries
watery diarrhea, fever, nausea, vomitting

Question 19

Q

E.Coli-Clinical

Answer

A

_Diagnosis (lactose fermenter): _
Culture different media-
MacConkey (pink)
EMB (green)
Classifying strains=API biotests
4 characteristics of E.coli-
Produces indole from tryptophan
Uses citrate as sole source of carbon
Decarboxylate lysine
Motile
Treat: Rehydration, self limiting

Question 20

Q

Enteroinvasive E.Coli (EIEC)-Inflammatory

Answer

A

Large Intestine
Virulence: Plasmid mediated invasion (plnv)
Invade colonic epi cells-Escape phagosome to multiply in cytoplasm & move to adj cells _{^{(shigella)}}
NO enterotoxin
Disease: IP 12-72 hrs
Infective does=10
Fever, cramping, watery diarrhea may progress to dysentery
Primary in under-developed countries ^{_{(rare in US)}}

Question 21

Q

Enterohemorrhagic-E.coli (EHEC)-Inflammatory

Answer

A

“Child w/HUS ate @ hamburger joint”
No human carrier ONLY cattle
High risk: Children under 5
Undercooked beef ^{(hamburger)}
Veges contaminated by animal feces ^(O104:H4)
Virulence factors:
Budle forming pili _^(Bfp-EPEC)-Attaching-effacing-Destruction of microvilli
Shiga-like toxin _{^{(verotoxin)}}-Inhibit protein synthesis kills epi/endo cells Large intestine (STEC)
Small infective dose=100

Question 22

Q

(EHEC)-Inflammatory/Clinical

Answer

A

_{^{Mild diarrhea->Hemorrhagic colitis}}
_{^{Little or no fever w/severe ab cramps}}
_{^{Watery diarrhea->Bloody diarrhea}}
HUS: toxin can reach blood=Kidney failure w/hemolytic anemia, thrombocytopenia w/minor Neuro symptoms
Treat: Use of antibiotics could contribute to HUS-Due to dying/dead bacteria shiga toxin & LPS released
Diagnose: Sorbitol MacConkey agar (pink)
O157:H7 non-sorbitol fermenter=Grey colonies
Detection of Shiga Toxin=Destruction of cells

Question 23

Q

Vibrio Cholera (GI)-General

Answer

A

“Comma shaped” bacilli
Gram (-)/Oxidase (+)
Motile w/single polar flagella
_{^{Need HIGH dose for infection (acid sensitive)}}
High risk:
_{^{Contaminated Water}}
_{^{Undercooked crabs, shrimps, oysters (V. para & vulnificus)}}
_{^{Flooded areas}}
_Disease: “cholera” _
_{^{HUGE amount of water loss w/Rice water diarrhea (contains mucus)}}
_{^{Hypokalemia due to massive dehydration}}
_{^{Loss of skin tugor w/weak pulse}}
Virulence factors: O1 & O139 make-
Cholera toxin- Similar to ETEC (LT)>binds to GM1 gangloside
_{^{Increase in cAMP=hyersecretion Cl-out NO Na+ in}}
Toxin-co-reg pilus (TCP)-Adhesion

Question 24

Q

Vibro Cholera (GI)-Clinical

Answer

A

Additional virulence factors: _{^{Absence of CT}}
Zonula Occludens toxin (zot)-protease degrades tight junctions=Mild diarrhea
Accessory cholera enterotoxin (ace)-Activates Ca+2 dependent Cl- channel
Symptoms:
_{^{Incubation 2-3 days}}
_{^{Abrupt onset (profuse watery diarrhea)}}
_{^{Colorless feces=”Rice water stools”}}
_{^{Dark field testing of Stool}}
Culture-Selective media-TCBS
^{_{Thiosulfate citrate bile salts sucrose Agar}}
_{^{Cholera turns YELLOW due acidity in Strong alkaline sol.}}
Serotyping-_{^{agglutination test using polyvalent sera Anti-O1 & O139}}
Treat-_{^{IV infusion (NaCl, KCl, NaHCO3) & Oral rehydration glcose + salt}}
Prevention-_{^{Chlorination of H2O & O1 oral Vaccination w/boosters}}

Question 25

Q

Calciviridae-Norovirus (GI)

Answer

A

_{^{Star of David virus particles}}
_{^{Positive ssRNA-NON enveloped icosahedral}}
_{^{Found in GI tract}}
High risk:
_{^{Food & water enviromentally stable}}
_{^{Outbreak in large groups (cruise ships)}}
_{^{Virus alters integrity of SI brush border}}
Symptoms:_{^{Incubation 1-2 days fever}}
_{^{Rapid onset of Vomiting & diarrhea 2-3 days}}
“winter vomiting disease”
Diagnosis: Clinical signs 1st
Treat: Self-limiting BUT use oral rehydration
Prevention: Sanitation
Resistant @ 60C, Low PH, & detergents/Chlorination
Re-infection or infection w/other genotype

Question 26

Q

Reoviridae-Rotavirus (GI)

Answer

A

Wheel-like=Rota/_{^{Segmented 11 parts}}
_{^{dsDNA, NON-enveloped icosahedral nucleocaspid}}
Stable over a WIDE range of temp/pH
High risk: Infants/children
Winter-spring months
Causes shortening & blunting of villi w/Mononuclear cell infiltration
Disease: Gastroenteritis
Icubation 1-3 days w/symptoms 3-8 days
Clinical triad=Fever, vomiting, diarrhea ^{_{(coryza/infection of URT & cough)}}
#1 cause of diarrhea in 6-24 months
Diagnosis: ID in stool
Treat: _{^{Children w/immunodef=Rotavirus-specific immunoglobulin prep (orally)}}
Vaccine-
Rotarix-_{^{HumanAttenuated-G1&P8 2 doses}}
RotaTeq-_{^{Bovine strain-express human VP4-7 (3) doses}}

Question 27

Q

Adenovirus (GI)

Answer

A

ds DNA, NON-eveloped 12 protruding fibers (penton) from corners of caspid
Found in Late fall-winter
High risk: Infants
Disease: Infantile diarrhea Inoculation 7-8 days w/symptoms 8-12 days
Watery diarrhea & fever
Diagnosis: Serotype 40/41 in stool
Other serotype:
Pharyngoconjunctival fever (pools)
Acute Rep disease (military)
Pneumonia

Question 28

Q

Astrovirus (GI)

Answer

A

Star-like shape for each virus particle
(+) ssRNA non-eveloped
#2 cause of infantile diarrhea _{^{(#1 rota)}}
High risk: Institutionalized Elderly & immunocomprimised children
Disease: Gastroenteritis _{^{(milder than rota)}}
Icubation 3-4 days, symptoms 5+ days
Winter Peak in temperate climates
NO vaccine

Question 29

Q

Shigella (inflammatory)

Answer

A

“Daycare Diarrhea”
Endemic=homosexual males & children
Dyenteriae _{^{(most severe)}} & Sonnei _{^{(common in USA)}}
Flexneri _^(poor) & Boydii _^(rich)
Gram (-) rods/Non-motile _{^{(salmonella is motile)}}
4 F’s _{^{(finger, food, flies, feces)}} Low dose _{^{(survives acidity)}}
Virulence-
Invasiveness _{^{(moving to neighbor cell w/o leaving)}}
_{^{Enter through M-cells, Enter macrophages which recruit IL-1 &8, Break out of macro to infect Epi cells @ basal surface, Final POLYMERIZE actin filaments (movement)}}
Enterotoxins & Shiga-toxin _^(verotoxin)

Question 30

Q

Shigella (inflammatory)-Virulence/Pathogenesis

Answer

A

Enterotoxins-Common in all 4
ShET1 & 2 _{^{(also found in EAEC)}}=Blocks absorption of electrolytes, glucose, & amino acids in GI lumen _{^{(watery diarrhea)}}
Shiga Toxins (AB)-S.Dysenteriae
_{^{Cytotoxin(stx)=Shiga kills GI epi & endo cells}}
_{^{Inhibits protein synthesis inactivating 60S}}
_{^{Synergy w/LPS=Inflammatory cytokines=Damage to endo of BV (bloody diarrhea)}}
Bacillary Dysentery (watery-Bloody) _{^{incubation 36-72hrs}}
Non-specific symptoms-fever & cramping
48 hrs after watery diarrhea
Dysentery (invasion & damage mucosa)

Question 31

Q

Shigella (inflammatory)-Clinical

Answer

A

HUS-Assoc w/Dysenteriae _{^{(shiga toxin)}}
_{^{Causes hemolysis, renal failure (uremia), DIC}}
_{^{Primary disease of infants & children}}
Reiter’s syndrome _{^{(reactive arhritis)}}-Autoimmune
_{^{2-4 weeks after Flexneri (poor) infection}}
_{^{Triad-“Can’t see, Can’t pee, Can’t climb a tree”}}
_{^{Men 20-40 years & HLA-B27 (Spondyloarthropathy)}}
Shigellosis=Self limiting w/water & electrolyte therapy
_{^{Antidiarrheal compounds inhibit peristalsis NOT recommended}}
Diagnosis-Non/lactose fermenter
Hektoen enteric agar_{^{(shigella/salmonella)}} Faint green color NON-H2S producer (differs from Salmonella)

Question 32

Q

Salmonella Enterica (Non-Typhodial Inflammatory)

Answer

A

Gram(-) rod, non-lactose fermenter
DOES make H2S & Motile _{^{(unlike Shigella)}}
Found in poultry, eggs, dairy products
Need HIGH infective dose=Acid sensitive
High risk: Children & elderly due low acid
Local invasion-ingestion, colonization in ileum/cecum, mucosal invasion (M-cells), inflammation, ulcers=Bloody diarrhea
Enterotoxins-Adenylate cyclase(cAMP), fluid production (large/small)=Watery diarrhea
Systemic invasion-Multiply in endosome/phagosome
Growth inside macrophage-Goes to lymphatics

Question 33

Q

Salmonella Enterica (Non-Typhodial Inflammatory)-Clinical

Answer

A

Gastroenteritis/Salmonellosis:
Incubation time 6-48hrs
Inflammatory diarrhea w/orw/o blood
Lasts 2-7 days self limiting
Systemic infection _{^{(sicklecell pts more susceptible)}}:
Enter blood through lymph=Septicemia
Brain _{^{(meningitis)}}, bone _{^{(osteomyelitis)}}, lungs _^(pneumonia)
Treat: neonates, elderly, sickle cell w/antibios
Diagnose: Hektoen enteric agar _{^(blue-green)}w/Hydrogen sulfide production _{^{(black center)}}

Question 34

Q

Campylobacter Jejuni-Inflammatory

Answer

A

_{^{Gram (-) comma or S shaped ROD}}
_{^{Polar flagella motile}}
Microaerophilic _{^{(O2 but lower lvls than atmosphere)}} _{^{& grows best @ 42C}}
_{^{Zoonotic(cattle, chickens, pets)}}
Transmission: _{^{Oral-fecal, water-food w/animal feces}}
Poultry, beef, milk-Food
Pets-Children
High risk: Young children, immunocompromised, decreased/neutral stomach acids _{^{(antiacids/milk)}}
_{^{Common cause of diarrhea in US & UK (treat w/antibiotics longer than 1 week)}}
_{^{Diagnose: Campy-BAP or Skirrow (antibiotics-Vancomycin, polymyxin B) selective of other enteric microorganisms, which grows @ 42C}}

Question 35

Q

Campylobacter Jejuni-Inflammatory (clinical)

Answer

A

Virulence & Pathogenesis:
Toxin production-invasion of epicells & survival in monocytes _{^(salmonella)}
Enterotoxin-Electrolyte movement _{^{(watery diarrhea)}}
_{^{Followed by inflammatory diarrhea-Invasion of epi=ulcers in bowel mucosa}}
_{^{Watery diarrhea w/foul smelling bloody feces (10+stools/day)}}
_{^{Mimic acute appendicitis (self-limiting)}}
_{^{Systemic infection: survives in monocytes then carried to other parts of body=Septicemia}}
Complications-Autoimmune
Guillain-Barre: Acute neuromuscular paralysis
_{^{Cross reactivity w/O Ag & glycosphigolipids (peripheral NS)}}
Reactive arthritis: inflammation of joints

Question 36

Q

Yersinia Spp-Inflammatory

Answer

A

_{^{Gram(-) rod NON-lactose fermenters}}
_{^{Grows @ 25C}} _{^{(cold enrichment)}} _{^{& motile BUT not @ 37C}}
_{^{Found in GI of animals}}
_{^{Contaminated food, Pet feces, High dose needed}}
High Risk: Any one in cold climate (North)
Virulence/Pathogenesis: Enterotoxin & invasion of mucosa-Inflammation=Ulceration
Systemic to mesenteric lymph=Mesenteric adentitis
- _{^{SEVERE ab pain in LRQ pseudo-appendicits}}
Complication=Reiter’s syndrome _{^{(HLA-B27-Same as shigella)}}
Diagnose: Stool culture “cold enrichment” 2-4 weeks Yersinia INCREASE and other microbes DIE

Question 37

Q

Clostridium Difficile-Inflammatory/General

Answer

A

Gram + rod & anaerobic spore former
Found in GI tract-High % colonies in Hospital pts
Transmission:
_{^{Endogenous or via spores}}
_{^{Fecal-oral (clothing, surfaces)}}
High Risk: _^Hospital
Long term Antibiotic use _{^{(ampicillin, cephalosporins, clindamycin)}}
_{^{Hospital pts-Long term stay (4weeks)}}
Anibiotic Assoc Diarrhea-_{^{Mild diarrhea to pseudomembranous colitis}} _{^{(4-10 days after antibio & 2weeks after termination)}}
_{^{Most common nosocomial diarrhea (hospital)}}

Question 38

Q

Clostridium Difficile-Inflammatory/Clinical

Answer

A

Adhesion (surface layer proteins)
Toxin A (enterotoxin)_{^{=Hypersecretion of fluid, induce inflammation (cytokine production & Hemorrhagic necrosis)}}
Toxin B (cytotoxin)_{^{=Depolymerization of actin, loss of cytoskeleton & cell death}}
Toxin C (Super BUG)_{^{=Deletion of A/B reg gene tcdC-Makes 20x more (resistant to antibios)}}
Pseudomembranous colitis- Severe ab pain, watery diarrhea w/high # of neutrophils in stool
_{^{Irreg yellow plaques nectotic debris (fibrin&mucus)}}
Diagnose: _{^{Toxin detection in stool or ELISA for A/B}}
Treat: _{^{Stop current antibio & use Metronidazole/Vancomycin}}
Restore normal GI flora=_{^{Saccharomyces boulardii or fecal transplant}}

Question 39

Q

Typhoidal Salmonella spp (Gen)

Answer

A

Typhi & Parathyi
Gram(-) rod/motile, non-lactose, produces H2S
Found in gallbladder up to 1 year
High risk: Poor hygiene & traverlers to endemic areas under 30 yrs old
Virulence: Multiplies in macrophages w/LPS
1st week=_{^{Fever w/bradycardia (no GI)}}
2nd week=_{^{GI w/rash on trunk/ab (Rose spots)}}
3rd week=_{^{hepatosplenomegaly w/GI bleeding (erosion to peyer’s patches)}}
_{^{Complications=shock, stupor, seizures, psychosis, myelitis, and pneumonia.}}

Question 40

Q

Typhoidal Salmonella spp (clinical)

Answer

A

W/GI perforation=Fatty degeneration
- _{^{Accum of fat in cells w/enlarged spleen, liver, mesenteric glands, kidney, & heart}}
DIC-Thrombophlebitis _{^{(vein inflammation=Blood clot)}}
_Diagnose: _
Specimen-Blood, bone, urine, stool w/chornic pt
Culture=Hektoen _{^{(non-lactose fermenter)}}
Serology=Widal test _{^{(test tube agglutination)-Detect Ab against O/H Ag}}
Treat: Borad spec fluroquinolones, cipro, ceftriaxone
Prevention: ID & treat carriers _{^{(removal of gallbaldder)}}
Vaccine: Capsular=VI & live attenuated=Ty21a
_{^{Both taken oral for traverler's in endemic areas}}