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Microbio-2 > GI tract Pathogens > Flashcards

GI tract Pathogens Flashcards

1
Q

Dental Plaque (Strep Viridans)

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 <u>(bacteremia)</u>
    • 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
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2
Q

Dental Plaque (Strep Viridans)-Clinical

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 <u>(nail bed)</u>
  • Treat: Penicillin (increasing resistance)
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3
Q

Mumps (Paramyxoviridae)

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<u> (winter/spring)</u>
  • Infection starts in resp tract>enters blood…
  • 1st systemic site of infection=<strong><em>Parotid gland</em></strong>
    • Multiplies in ductal epi cells>Swelling w/pain
  • secondary sites=Testes, ovaries, CNS, & pancreas (juvenile diabetes)
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4
Q

Mumps (Paramyxoviridae)-Clinical

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=<u><strong>Sterility</strong></u>
    • Due to fiborous <strong><u>Tunica Albuginea</u></strong>
  • 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 <u><strong>w/2 doses</strong></u>
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5
Q

Peptic Ulcers (H. Pylori)

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 <u>(mucins)</u>
  • Phospholipases-Hydrolyze phospholipids
    • <strong>Urease</strong>-Breaks urea to Co2/NH3=<em>Neutralize gastric acid</em>
  • <u>Vacuolating cytotoxin </u>A-Damage epi cells w/vacuoles
  • Cytotoxin assoc gene-Destroy epi cell cytoskelton
    • <strong>Type 4 secretion-<u>"</u></strong><u>Inject" </u>CagA to epicells
    • Cag+ = Gastroadenocarcinoma
  • LPS-Inflammatory response <u>(PMN/Mononuclear cells)</u>
  • Further destruction done internally by digestive enzymes/acid
    • Ulcer formed
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6
Q

H. Pylori-Clinical

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 <u>(omeprazole)</u>
    • Macrolides (<u>clarithromycin)</u>
    • Beta-lactam (<u>amoxicillin)</u>
    • Metronidazole
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7
Q

Enteric Infections (Diarrhea)

A
  • Proximal Small intestine (non-Inflammatory):
  • Watery diarrhea &+/- vomit w/Superficial invasion
  • Pathogen alter water/electrolyte movement
  • Larger vol of feces w/<em><u>NO leukocytes</u></em>
  • 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:
  • <em><u>Systemic penetration</u></em> (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
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8
Q

Staph Aureus (GI)

A
  • Gram (+) cocci, Catalase/Coagulase (+)
    • Growth @ 7.5 NaCl
  • Found in nose, skin, LOW lvls in colon/vagina
  • Consumption of contaminated foods-
  • Food handler<u> <em>(picks nose)</em></u>
  • 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<strong><u> (ingesting toxin)</u></strong>
  • Emetic activity<strong>(<u>cereulide)</u></strong>=Stims vagus nerve in stomach lining <u>(vomit)</u>
  • SuperAg activity=Stims T-cell proliferation=<em><u>Release of TNFa/IFNy into BS</u></em>
  • Sudden onset less than an HOUR
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9
Q

Bacillus Cereus (GI)

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 (<u>boiled rice/pasta</u>) held @ ambient temp too long
  • Enterotoxin superAg=<u><strong>Cereulide</strong></u>-stims vagus nerve (vomit)
  • <u>Rapid onset </u>1-6 hrs symptoms 24 hrs
  • PROFUSE vomiting w/<u><strong>NO fever or diarrhea</strong></u>
  • 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
  • <em><u>Slower onset</u></em> 6-16 hrs
  • <u><em>Watery diarrhea</em></u>, vomiting, cramps
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10
Q

Bacillus Cereus-Other infections

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
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11
Q

Clostridium Botulinum (GI)-General

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 <em><u>(Homemade)</u></em>
  • Fermented fish <em><u>(Alaska)</u></em>
  • Improperly sterilized commercial canned alkaline veges <u>(green beans, peppers,mushrooms)</u>
  • IV-black tar heroin
  • Infants less than 1 year old w/honey <u>(inhalation common)</u>
  • Prison wine outbreak
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12
Q

Clostridium Botulinum (GI)-Disease

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<u>/canned foods</u>
  • Type E associated w/<u>Fish</u>
  • Absorbed in gut>blood stream
  • Binds @ pre-synaptic neuron>cleaves protein involved w/release of Ach (exotoxin)
    • SNARE proteins <u><em>(synaptobrevin/Syntaxin)</em></u>
    • 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 <em><u>(diarrhea or constipation)</u></em> untreated bilateral DESCENDING paralysis
  • Wound (infection)-Incubation 1-4 days symptoms similar to food borne <strong><u>(Black-tar heroine)</u></strong>
  • Dry-Furrowed tongue
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13
Q

Clostridium Botulinum (GI)-Clinical

A
  • Infant botulism: “floppy baby”
  • Most common in US
  • Incubation=3-30 days
  • Ingestion of spore and germinates in GI due to low flora<u><em>(multiply in gut-make toxin)</em></u> absorbed in blood
  • Associated w/Honey & dust inhalation
  • <u><strong>Symptoms:</strong></u> Lethargy, constipation, poor feeding <u><em>(sucking reflex)</em></u>, Facial paralysis
  • Diagnosis: Toxin in pt’s blood/Infant’s stool
  • Treat: Antiobios=Wound (not infants could worsen)
    • Passive immunization <strong>ANTI-toxin</strong> (A,B,E)
    • Anti-bios NOT used in Infants due to worsening the condition <u>(killing flora)</u>
  • Prevention: Heating canned foods
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14
Q

Clostridium Perfringens (GI)-General

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
    • <strong><em>Enterotoxin-</em></strong>Heat liable <em><u>(B.cereus) </u></em>Increase cAMP=<u><em><strong>Watery diarrhea</strong></em></u>
    • <em>Increases intracellular Ca+2 </em>alters membrane perm=Loss of fluids/macomols
  • Incubation: 8-16 hours will last 24 hours in immunocomprimised 1-2 weeks
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15
Q

Enterobacteriaceae (GI)-Non/inflammatory

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 <em><strong>O-Ag</strong><u> (LPS)</u></em>
  • MacConkey & Eosin methylene blue agar for Lactose fermentation:
    • Low pH = Pink in MAC
    • Gram (-) ONLY
  • TSI: Contains 3 sugars (glucose, sucrose, lactose)
    • Lactose & Sucrose=<u>Large amount of acid</u>
    • Glucose=<u>Less amount of acid</u>
    • 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
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16
Q

E. Coli (GI)-General

A
  • 5 groups classified by virulence factor
  • Non-inflammatory <strong>(Small intestine-lumen)</strong>
  • <u>Enterotoxigenic (ETEC)</u>: travelers & infants in developing countries=<em><u>Watery diarrhea &amp; nausea</u></em>
  • <u>Enteropathogenic (EPEC)</u> & <u>Enteroaggregative (EAEC)</u>: Childhood diarrhea
  • Gram (-) Rod=Lactose fermenter
  • Most common bacilli in GI tract
  • _Virulence factor: _
  • Exotoxins-
  • <u>Heat stable toxin </u><em><u><u>(ST</u>)-</u></em><strong>Excess cGMP</strong>=Blocks ion transport INTO cells>water moves into LUMEN
  • <u>Heat liable toxin </u><em><u>(LT)-s</u>imilar to cholera toxin</em>
  • <em>binds to GM1 ganglioside receptors on Gut>I<strong>ncrease cAMP </strong>outflow of Cl-<strong>=Inihibition of Na+ absorption</strong></em>
  • Ion imbalance=Water loss=<strong>Diarrhea</strong>
  • Shiga like toxin <em><u>(STx)</u></em>
  • Adhesion-
  • <u>Colonizing factor adhesions </u><em><u><u>(CFA)</u>-</u></em>Fimbriae recognize host glycoprotein receptor
  • bundle forming pili <em><u>(Bfp)</u></em>
  • adherance fimbriae <em><u>(AAF)</u></em>
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17
Q

EAEC-Enteroaggregative (GI)

A
  • Aggregative adherence fimbriae (AAF):
  • Bacterial clumping into small aggregates
  • Stacked bricks-Bacteria parallel rows<u> (autoagglutination)</u>
  • <u>Stimulates mucus production-</u>Mucus + Bacterial aggregates =<em><strong> Biofilm</strong></em>
  • Biofilm>ST toxin <u>(heat stable</u><em>)=Excess cGMP </em>interferes w/ ion absorption
  • <strong><em>Cytotoxin/hemolysin</em></strong>=Shortening of microvilli><strong><em>Decreased</em></strong> fluid absorption
  • Disease: Presistant watery diarrhea w/vomiting & dehydration NO fever
  • Lasts 14 + days
    • Infantile chronic diarrhea=<strong><em>Growth retardation</em></strong>
    • Travelers’ diarrhea in HIV pts
18
Q

EPEC-Enteropathogenic (GI)

A
  • Virulence factors:
  • Bundle forming pili (Bfp)-patchy adherence>Tir insertion & intimin binding
  • Attaching>effacing=<em><strong>Destruction of microvilli</strong></em>
  • Forms cup-like pedestal structure in cytoplasm made of <u><em>Cytokeretin 18 =</em></u><em><strong>dense mat of actin fiber under EPEC (attaches to apical membrane)</strong></em>
  • TYpe 3 injection system (Tir) allows for attachment and eventual Destruction of microvilli=<strong><em>Malabsorption=Diarrhea</em></strong>
  • Disease: “Infantile diarrhea”
  • Epidemics in newborn nurseries
  • watery diarrhea, fever, nausea, vomitting
19
Q

E.Coli-Clinical

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
20
Q

Enteroinvasive E.Coli (EIEC)-Inflammatory

A
  • Large Intestine
  • Virulence: Plasmid mediated invasion (plnv)
  • Invade colonic epi cells-Escape phagosome to multiply in cytoplasm & move to adj cells <strong>(shigella)</strong>
  • NO enterotoxin
  • Disease: IP 12-72 hrs
  • Infective does=10
  • Fever, cramping, watery diarrhea may progress to dysentery
  • Primary in under-developed countries <strong>(rare in US)</strong>
21
Q

Enterohemorrhagic-E.coli (EHEC)-Inflammatory

A
  • “Child w/HUS ate @ hamburger joint”
  • No human carrier ONLY cattle
  • High risk: Children under 5
  • Undercooked beef <strong>(hamburger)</strong>
  • Veges contaminated by animal feces (O104:H4)
  • Virulence factors:
  • Budle forming pili (Bfp-EPEC)-Attaching-effacing-Destruction of microvilli
  • Shiga-like toxin <u><strong>(verotoxin)</strong></u>-Inhibit protein synthesis kills epi/endo cells Large intestine (STEC)
  • Small infective dose=100
22
Q

(EHEC)-Inflammatory/Clinical

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
23
Q

Vibrio Cholera (GI)-General

A
  • “Comma shaped” bacilli
  • Gram (-)/Oxidase (+)
  • Motile w/single polar flagella
  • Need HIGH dose for infection <strong><u>(acid sensitive)</u></strong>
  • High risk:
  • Contaminated Water
  • Undercooked crabs, shrimps, oysters <strong><u>(V. para &amp; vulnificus)</u></strong>
  • Flooded areas
  • _Disease: “cholera” _
  • HUGE amount of water loss w/Rice water diarrhea <u>(contains mucus)</u>
  • 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
24
Q

Vibro Cholera (GI)-Clinical

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<u> (profuse watery diarrhea)</u>
  • 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><em>Strong alkaline sol</em></strong>.
  • Serotyping-agglutination test using polyvalent sera Anti-O1 & O139
  • Treat-IV infusion <u>(NaCl, KCl, NaHCO3)</u> & Oral rehydration glcose + salt
  • Prevention-Chlorination of H2O & <em>O1 oral Vaccination w/boosters</em>
25
Q

Calciviridae-Norovirus (GI)

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
26
Q

Reoviridae-Rotavirus (GI)

A
  • Wheel-like=Rota/Segmented 11 parts
  • dsDNA,<em><u> NON-enveloped</u></em> 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 (<u>orally)</u>
  • Vaccine-
  • Rotarix-HumanAttenuated-G1&P8 2 doses
  • RotaTeq-Bovine strain-express human VP4-7 (3) doses
27
Q

Adenovirus (GI)

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
28
Q

Astrovirus (GI)

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
29
Q

Shigella (inflammatory)

A
  • “Daycare Diarrhea”
  • Endemic=homosexual males & children
  • Dyenteriae <strong>(most severe)</strong> & Sonnei <strong>(common in USA)</strong>
  • Flexneri (poor) & Boydii (rich)
  • Gram (-) rods/Non-motile (salmonella is motile)
  • 4 F’s <strong>(finger, food, flies, feces)</strong> Low dose <strong>(survives acidity)</strong>
  • 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)
30
Q

Shigella (inflammatory)-Virulence/Pathogenesis

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
  • <em><strong>Cytotoxin(stx)=Shiga</strong></em> kills GI epi & endo cells
  • Inhibits protein synthesis inactivating 60S
  • Synergy w/LPS=Inflammatory cytokines=Damage to endo of BV (<em><strong>bloody diarrhea)</strong></em>
  • Bacillary Dysentery (watery-Bloody) <strong>incubation 36-72hrs</strong>
  • Non-specific symptoms-fever & cramping
  • 48 hrs after watery diarrhea
  • Dysentery (invasion & damage mucosa)
31
Q

Shigella (inflammatory)-Clinical

A
  • HUS-Assoc w/Dysenteriae (shiga toxin)
  • Causes hemolysis, renal failure <u><strong>(uremia)</strong></u>, DIC
  • Primary disease of infants & children
  • Reiter’s syndrome (reactive arhritis)-Autoimmune
  • 2-4 weeks after Flexneri (poor) infection
  • Triad-“<strong>Can’t see, Can’t pee, Can’t climb a tree”</strong>
  • Men 20-40 years & HLA-B27 <u><strong>(Spondyloarthropathy)</strong></u>
  • 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)
32
Q

Salmonella Enterica (Non-Typhodial Inflammatory)

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
33
Q

Salmonella Enterica (Non-Typhodial Inflammatory)-Clinical

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 <strong>(meningitis)</strong>, bone (osteomyelitis), lungs (pneumonia)
  • Treat: neonates, elderly, sickle cell w/antibios
  • Diagnose: Hektoen enteric agar (blue-green) w/Hydrogen sulfide production <strong>(black center)</strong>
34
Q

Campylobacter Jejuni-Inflammatory

A
  • Gram (-) comma or S shaped ROD
  • Polar flagella motile
  • Microaerophilic (O2 but lower lvls than atmosphere) & grows best @ 42C
  • Zoonotic<strong>(cattle, chickens, pets)</strong>
  • 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 <u><strong>(treat w/antibiotics longer than 1 week)</strong></u>
  • <u><strong>Diagnose:</strong></u> <em><strong>Campy-BAP or Skirrow</strong></em> <u>(antibiotics-Vancomycin, polymyxin B)</u> selective of other enteric microorganisms, which grows @ 42C
35
Q

Campylobacter Jejuni-Inflammatory (clinical)

A
  • Virulence & Pathogenesis:
  • Toxin production-invasion of epicells & survival in monocytes (salmonella)
  • Enterotoxin-Electrolyte movement (watery diarrhea)
  • Followed by inflammatory diarrhea-Invasion of epi=<em><strong>ulcers in bowel mucosa</strong></em>
  • Watery diarrhea <em><strong>w/foul smelling bloody feces (10+stools/day)</strong></em>
  • <em><strong>Mimic acute appendicitis (self-limiting)</strong></em>
  • <em><strong><u>Systemic infection:</u> </strong></em>survives in monocytes then carried to other parts of body=Septicemia
  • Complications-Autoimmune
  • Guillain-Barre: Acute neuromuscular paralysis
  • Cross reactivity w/O Ag & glycosphigolipids <u><strong>(peripheral NS)</strong></u>
  • Reactive arthritis: inflammation of joints
36
Q

Yersinia Spp-Inflammatory

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
37
Q

Clostridium Difficile-Inflammatory/General

A
  • Gram + rod & anaerobic spore former
  • Found in GI tract-High % colonies in Hospital pts
  • Transmission:
  • Endogenous or via spores
  • Fecal-oral <u>(clothing, surfaces)</u>
  • 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 <u>(hospital)</u>
38
Q

Clostridium Difficile-Inflammatory/Clinical

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 <u>(resistant to antibios)</u>
  • 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
39
Q

Typhoidal Salmonella spp (Gen)

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 <strong>(Rose spots)</strong>
  • 3rd week=hepatosplenomegaly w/GI bleeding <strong>(erosion to peyer’s patches)</strong>
  • <u><strong>Complications=</strong></u>shock, stupor, seizures, psychosis, myelitis, and pneumonia.
40
Q

Typhoidal Salmonella spp (clinical)

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 <u><strong>oral for traverler's</strong></u> in endemic areas

Microbio-2 (20 decks)

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