Microbiology 2

3 Diseases caused by Neisseria meningitidis

1. Meningococcemia
2. Waterhouse-Friderichsen syndrome
3. Meningitis

Waterhouse-Friderichsen syndrome

-AKA fulminant meningococcemia
-Septic shock
-Bilateral hemorrhage into adrenals
-Abrupt onset of hypotension and tachycardia
-Petechial lesions
-Eventually DIC

Treatment for Neisseria gonorrhoea

Ceftriaxone + tx doxy or azithro to cover chlamydia

Meningococci
-virulence factor
-fermentation
-vaccine?
-How is it spread?

-polysaccharide capsule
-Ferments maltose and lactose (gonococci only ferments lactose)
-vaccine available
-spread via respiratory and oral secretions

Enterics
-Antigens

-O antigen - most external component of LPS of gram _
-K antigen - capsule that covers O antigen
-H antigen - makes up subunits of bacterial flagella

Which gram - groups are classified as "enterics"?

Enterobacteriaceae
Vibrionaceae
Pseudomonadaceae
Bacteroidaceae

Members of Enterobacter family (7)

E. coli
Salmonella
Shigella
Klebsiella
Enterobacter
Serratia
Proteus

Types of E. Coli (3)

1. Enterotoxigenic ETEC
2. Enterohemorrhagic EHEC
3. Enteroinvasive EIEC

Enterotoxigenic E. Coli
ETEC

"Traveler's diarrhea"
-Pili
-Does NOT invade epithelial cells but binds to them and releases exotoxins (2)
-Heat Labile (LT) - like cholera toxin
-ST - inhibit reab. of NaCl and stimulate secretion of Cl- and HCO3 (causes osmotic diarrhea)
-Severe watery

Enterohemorrhagic E. coli
EHEC

-Pili colonization
-Secretes Shiga-like toxin (inhibits protein synthesis of 60S ribosome, results in epithelial cell death)
-Diarrhea is bloody with severe abd. cramping
-Also causes HUS

Hemolytic Uremic Syndrome
(HUS)
-What is is caused by?
-Symptoms

Associated with infection by a strain of EHEC, 0157:H7
-Causes anemia, thrombocytopenia and renal failure
-Outbreaks d/t infected meat.

Enteroinvasive E.Coli

-Same disease caused by Shigella
-Main virulence factor = ability to invade epithelial cells
-Also produces Shiga-like toxin
-Immune-mediated inflammatory rxn with fever

Non-diarrheal diseases caused by E. coli

UTI
Meningitis (neonatal)
Sepsis (hospitalized pts)
Pneumonia (hospital-acquired)

Klebsiella pneumoniae
-What does it cause?

-Gram - Enteric
-pneumonia in hospitalized pts and alcoholics (aspiration). Sputum looks like red currant jelly
-Sepsis
-Nosocomial UTIs

Proteus Mirabilis
-Classification
-What does it cause?

-Gram - enteric
-Causes UTIs and other nosocomial infections
-VERY motile!

Lactose fermenting enteric bacteria

Klebsiella
E. coli
Enterobacter
Grow pink colonies on MacConkey's agar

Shigella
-motile?
-Lactose fermenter?
-Virulence factors?
-Illness
-Transmission
-Normal flora?

-Non-motile
-Does NOT ferment lactose
-Shiga toxin (causes cell destruction)
-Causes illness like EIEC with abd pain and diarrhea and fever. Inflamed and damaged colon unable to reabsorb electrolytes

Salmonella
-Motility? Lactose? H2S?
-Disease it causes
-Virulence

-Motile, non-lactose fermenter, produces H2S
-Causes typhoid fever and gastroenteritis
-Capsule called Vi antigen

Salmonella typhi

AKA enteric fever
-Like Shigella/EIEC but then invades regional lymph nodes, seeding multiple organ systems
-Facultative intracellular parasite
-Illness begins with fever, HA abd pain, diarrhea, rose spots on abdomen
-Can become chronic carrier; bacteria

Yersinia Enterocolitica
-Disease?
-Tranmission
-Mimics?

-Causes acute gastroenteritis with fever, diarrhea, and abd pain
-Usually transmitted from pet feces, milk, or pork
-Mimics Appendicitis or Crohn's

Vibrio Cholera
-classification
-Disease
-Transmission

-Enteric gram - rod
-Cholera - same as ETEC (no invasion). Toxin called choleragen. Severe watery diarrhea (rice water). Death from dehydration can result.
-Fecal/Oral - contaminated water supply

Cholera toxin (choleragen)

Activates Gs which leads to increased cAMP which results in active secretion of NaCl and osmotic diarrhea.

Vibrio parahemolyticus

Causes gastroenteritis after ingestion of uncooked seafood (Japan)

Campylobacter Jejuni
-classification
-transmission
-disease

-Enteric gram - rod
-Zoonotic disease; fecal/oral contaminated water
-Illness has a prodrome of fever/HA following by abd pain and bloody diarrhea.
-Invades lining of small intestine and spreads systemically.

Helicobacter pylori

-most common cause of duodenal ulcers and chronic gastritis
-Pepto inhibits its growth
-Can be treated with metro, ampicillin and/or tetracycline

Pseudomonas aeruginosa
General Info

Enteric gram - rod (obligate aerobe)
Colonizes and infects hospital/immunocompromised
Very resistant to Abx
Produces blue/green pigment and grape smell
Has Exotoxin A and endotoxin
Treat with aminoglycosides + broad spectrum PCN like piperacillin, ticarc

Illnesses caused by pseudomonas

Wound and burn infections
Pneumonia in CF
Sepsis (black lesions on skin)
External otitis
UTI (nosocomial)
Osteomyelitis in DM and IVDA

Bacteroides fragilis
-Virulence factor
-Disease

-One of few G- bacteria that does NOT contain Lipid A/Endotoxin
-Capsule
-Normal intestinal flora
-Can causes infection/abscess if gets into peritoneal cavity thru injury or surgery

Haemophilis Influenza

-Virulence from polysaccharide capsule (B is worst type)
-Gap in immunity in kids 6 months to 3 years
-Aerosol transmission
-Culture on chocolate agar
-Causes meninigitis, epiglottitis, Otitis media, Pnemonia, sepsis
-Treat with ceftriaxone; Rifampin prop

Haemophilis Ducreyi

-Causes STI Chancroid
-presents as PAINFUL genital ulcer with unilateral painful swollen LNs

Bugs causing bloody diarrhea

-Campylobacter
-Salmonella
-Shigella
-EHEC
-Yersinia enterocolitica
-C. difficile (can also cause watery)
Entamoeba histolytica

Bugs causing watery diarrhea

-ETEC
-Vibrio cholera
-C. perfringes
-Protozoa
-Viruses

cAMP inducers (4)

1. Vibrio cholerae activates Gs
2. Pertussus toxin disables Gi
3. E. coli heat labile toxin
4. B. athracis toxin includes edema factor, a bacterial adenylate cyclase
(first 3 act via ADP ribosylation)

Garnerella vaginalis

Together with anaerobes causes BV.
Itching and copious fishy discharge
Clue cells on micro exam
Treat with metro

Bordetella pertussis
-virulence factors
-disease patterns
-vaccine

-Pertussis toxin, extra-cytoplasmic adenylate cyclase, FHA (filamentous hemagglutinin), tracheal cytotoxin
-Causes whooping cough. Catarrhal stage of 1-2 weeks of typical URI
Paroxysmal stage during which pt develops bursts of coughing and can become hyp

Legionella pneumophila
-Transmission
-Diseases (2)

-Transmitted via aerosolized contaminated water, NOT person-to-person
-Causes pontiac fever (milder influenza-like illness) and Legionnaire's disease (common cause of CAP in people over 50)

Yersinia Pestis
-disease
-vector
-carrier animals
-treatment

-causes bubonic plaque (deadly if untreated)
-flea is the vector-
-rodents
-gentamycin

Brucella
-disease
-who gets it/transmission

-brucellosis - fever, chills, sweats, anorexia, H/A. Fevers come and go, "undulating fever"
-Transmitted via infected animal meat, infected milk. Usually meat-packing industry workers.

What makes chlamydia a unique Gram - organism?

-it is an obligate intracellular parasite (needs host's ATP)
-No peptidoglycan layer or muramic acid

Chlamydia life cycle

Elementary bodies: infectious particle that attaches to and enters cell - once inside transforms to RB (some of these eventually turn back into EBs to infect more cells)
-Reticulate body - Replicates within the cell by fission

Chlamydia trachomatis
-diseases
-transmission
-treatment

-reactive arthritis (Reiter's) conjunctivitis, non-GC urethritis, PID
-sexually transmitted or hand-to-hand transmission of eye secretions (with trachoma)
-Treat with doxy or azithro + ceftraxone to cover GC

Chlamydia strains that cause atypical pneumonia (2)

C. psittaci and C. pneumoniae
Treat with erythro/tetra

Classic triad for Rickettsial diseases (except Q fever)

Headache
Fever
Rash

Rickettsia family characteristics

-obligate intracellular parasites that need ATP, CoA and NAD
-arthropod vector (except Q fever)
-Tropism for endothelial cells
-Treatment with tetracycline

Which test is used to confirm Rickettsia infection?

Weil-Felix (except Q fever)

Rickettsia rickettsii
-disease
-vector
-sx
-endemic where?

-Rocky mountain spotted fever
-wood tick or dog tick
-fever, headache, rash that starts on palms and soles (Rickettsia on the rists, typhus on the trunk)
-east coast (southeast)

Rickettsia prowazekii

-Causes epidemic typhus
-Vector is louse
-Causes abrupt onset fever, HA with rash on trunk.
-Treat with tetra and chloramphenicol

Rickettsia typhi

-Causes endemic typhus
-vector is rat flea
-Not as severe as epidemic typhus
-Treat with tetracycline and chloramphenicol

Coxiella burnetti

-has an endospore form
-transmission via aerosolized particles from tick feces, cow placentas
-Mild pneumonia (Q fever)

Erlichia chaffeensis

-Causes human erlichiosis
-fever, headache, rarely rash

Spirochetes
-three families
-type of flagella

-Treponema, Borrelia, Leptospira

Primary syphilis

Painless chancre, nontender regional lymphadenopathy. Occurs ~ 6 weeks after infection and disappears by 4-6 weeks.

Secondary syphilis

Bacteremic stage
Occurs about 6 weeks after healed chancre
Constitutional sx
Maculopapular rash on palms/soles
Condyloma lata
Contagious!

Tertiary syphilis

Gummas
Aortitis
Neurosyph (Tabes dorsalis causes ataxia, + Romberg)
Argyll Robertson pupils

Borrelia burgdorferi
-disease
-transmission
-endemic where
-season

-Lyme disease
-Transmission via Ixodes tick
-endemic to NE US
-Summer

3 Stages of Lyme disease with Sx

1. Erythema chronicum migrans (expanding bull's eye red rash with central clearing), flu-like sx
2. Neuro and cardiac sx (Bell's palsy, meningitis, neuropathy and heart block)
3. Chronic monoarthritis, migratory polyarthritis

Leptospira
-where bacteria are found
-illness
-Weil's disease?

-bacteria found all over the world in urine of animals (contaminates water)
-Causes illness with flu-like symptoms and jaundice
-Weil's disease is a more severe form with jaundice, azotemia, fever, hemorrhage, anemia