Gram - Bacteria Flashcards
Greenish metallic sheen
E coli
3 antigens of E coli contributing to virulence
Capsular (K) Antigen
O antigen (Somatic Ag)
Flagellar (H) Antigen
Causes neonatal sepsis and meningitis from E coli
K1 capsule endotoxin
2nd most common cause of neonatal meningitis
E coli
Causes traveller’s diarrhea
E Coli TEC
Associated with HUS Undercooked beef (hamburger)
EHEC O157 H7
Traveller’s diarrhea is also known as
Montezuma’s revenge
Microangiopathic anemia/hemolytic anemia
Thrombocytopenia
Renal failure
HUS
Toxin causing HUS
Verotoxin (Shiga-like)
Outbreak in Germany associated with HUS
Contaminated food
Spinach
EHEC 0104:H2
E coli strains associated with outbreaks of diarrheal illness in hospital nurseries
Enteropathogenic (EPEC) E Coli
UTI
Honeymoon cystitis
E Coli
Bacteriologic index of water uses
E Coli
For drinking water, E coli must be
< 1 CFU
Gram - bacilli
Most common cause on anaerobic infections in the GI tract
Predominant flora of the intestine
Infection in adjacent organ
Abscess formation
Bacteroides fragilis
Bacteroides fragilis Dx
Non hemolytic
BBE + (bacteroides bile escalin agar)
Bacteroides fragilis is resistant to 3 potency disks
Kanamycin
Vancomycin
Colistin
Most commonly isolated members of B fragilis
B fragilis
B ovatus
B distasonis
B vulgatus
Most distinguishing pathogenic feature of B fragilis is the ability to cause
abscess formation
Gram - bacilli
Raw eggs
Polluted water
Salmonella typhi
Reservoir of S typhi
Gallbladder
Salmonella typhi dx
Typhidot Widal test (agglutination test) not reliable
Most common manifestation of Typhoid fever
Fever >75%
Abdominal pain 30-40%
Typhoid PE
Rose spots or rash 30%
Hepatosplenomegaly
Epistaxis
Relative bradycardia
Ileitis
Hepatosplenomegally
Fever
Dysentery
Tyhpoid fever
Lymphoid tissue hyperplasia Necrosis of Peyer’s patches Hepatitis Focal necrosis of liver Inflammation of GB, periosteum, lungs and other organs
Salmonella typhi
Hyperplasia of Peyer’s Patches
Typhoid ileitis
Fever + history of recent travel to developing country
S typhi
S typhi definitive diagnosis
Isolation of s typhi
Typhoid fever 1st week
Blood
Typhoid fever 2nd week
Urine
Typhoid fever 3rd week
Stool
Highest sensitivity of specimen for isolating S typhi
Bone marrow
S typhi empirical treatment
Ceftriaxone
Azithromycin
Fully susceptible Typhoid Tx
Ciprofloxacin
Azithromycin
Multidrug resistant Typhoid
Ceftriaxone
Azithromycin
Typhoid fever drug of choice
Ceftriaxone
Non-typhoidal salmonella infection Tx
Preemptive Tx
Severe gastroenteritis Tx
Not salmonella typhi
Ciprofloxacin
Typhoid meningitis Tx
Endocarditis or Arteritis
Bacteremia
Other localized infection
Ceftriaxone
Meningitic dose
2g IV q12
Patient with acute bloody diarrhea and fever
Endotoxin-mediated
Invades M cells - produces shallow ulcers
Shigella
Shigella toxin
Shiga toxin by S dysenteriae Type I neurotoxic, cytotoxic, enterotoxic, anti human ribosome (60s)
M cells are found in
MALT
Transmission: Finger, food, feces, flies
Ssx: tenesmus, watery then bloody diarrhea
+ anti-O antibody agglutination test
Shigella dysenteraie
Shigella sonei
Shigella causes
Bacillary dysentery
Shigellosis (Shigella sonei)
S dysenteriae causes most severe form of bacillary dysentery
S dysenteriae Type A
Most common cause of epidemic dysenteriae
S dystenteriae Type A
Shigellosis Tx
Ciprofloxacin (first line)
Pivmecillinam (second line)
Ceftriaxone
Azithromycin
Ciprofloxacin SE in children
Tendon rupture
Cartilage damage
Early closure of epiphyseal plates
Gram - curved bacilli
Oxidase +
Single polar flagella
Grow well in alkali pH up to 9
Vibrio
Vibrio culture medium
Thiosulfate citrate bile salt sucrose agar (TCBS)
Toxin of Vibrio
Choleragen
V cholera serotype associated with epidemics
O-1 eltor
Cholera subunits
A - activates adenylate cyclase
B - binding
Rice water stool
Pea soup stool
Vibrio cholerae
Thirst
<5% loss of total body weight
None or mild dehydration
Unconsciousness Lethargy Floppiness Weak or absent pulse Inability to think
Severe dehydration
ORS component
Glucose 75 Na 75 K 20 Cl 65 Citrate 10
Total osmolarity: 245
Home made ORS alternative
1/2 tsp salt
6 tsp table sugar
1 L drinking water
Most common cause of death in Shigella
Hypovolemic shock
V cholerae drug of choice
Tetracycline
Longest half life: Doxycycline
Associated with GE and seafood ingestion
Self limiting watery diarrhea
V parahemolyticus
V parahemolyticus toxin
Hemolysin
Vibrio Cellulitis Gastroenteritis Septicemia with liver disease Associated with shellfish
Flesh eating bacteria
Vibrio vulnificus
Cholera Tx
Fluid replacement
2 antibiotics used to shorten disease and reduce carriage state in cholera
Doxycycline
Ciprofloxacin
Selective medium for isolation of vibrio cholerae
TCBS
Minimum inoculin for Vibrio cholera
10^7
