NON-LACTOSE FERMENTING GRAM NEGATIVE RODS Flashcards
motile
OXIDASE (-)
H2S producer
Salmonella spp
nonmotile
OXIDASE (-)
H2S non producer
Shigella spp
swarming
OXIDASE (-)
H2S producer
UREASE
Proteus mirabilis
H2S non producer
OXIDASE (+)
obligate aerobe
Pseudomonas aeruginosa
ENTEROCOLITIS
-invasion of the epithelial and subepithelial tissue of the small and large intestines
S. enteritidis/S. typhimurium
TYPHOID FEVER
-d.t. Vi (virulence) capsular antigen
- organisms enter, multiply in the PEYER PATCHES and spread in reticuloendothelial system
- predilection for invasion of the GALLBLADDER – chronic carrier state
- FEVER and BRADYCARDIA (pulse fever disproportion)
- ROSE SPOTS
S. typhi
Septicemia
- bacteremia results in the seeding of many organs
- MC sequelae - osteomyelitis, pneumonia and meningitis
S. choleraesuis
-commonly in patients w/ SICKLE CELL ANEMIA or cancer
incubation period - 12-48 hrs
nausea and vomiting – abdominal pain and nonbloody diarrhea
Enterocolitis
Culture Source (Typhoid Fever) - WEEK 1 *stepwise fever, anorexia, malaise, relative bradycardia and bacteremia
BLOOD
bone marrow
Culture Source (Typhoid Fever) - WEEK 2
*abdominal pain, bloating, constipation, ROSE SPOTS, hepatosplenomegaly, jaundice
URINE
rose spots
bone marrow
Culture Source (Typhoid Fever) - WEEK 3
- bleeding ileitis - ulceration in hyperplastic follicles
- pneumonia
STOOL
bone marrow
Culture Source (Typhoid Fever) - WEEK 4
*recovery or death
bone marrow
POST - chronic carrier state
BILE
stool
bone marrow
Treatment for Uncomplicated Typhoid Fever
Ampicillin
Amoxicillin
Treatment for Complicated Typhoid Fever
Ceftriaxone
8 y/o African male with sickle cell anemia develops osteomyelitis. Which is the most likely etiology
Salmonella
HEALTHY - Staphylococcus aureus
Osteomyelitis in a specific conditions
BURNS - Pseudomonas aeruginosa
IV DRUG ABUSERS - Staphylococcus aureus and Pseudomonas aeruginosa
SICKLE CELL ANEMIA - Salmonella choleraesuis
Species and strains of Shigella
Shigella sonnei - Duval’s bacillus
*MCC OF BACILLARY DYSENTERY
Shigella dysenteriae type I - Shiga bacillus
- MOST SEVERE FORM OF BACILLARY DYSENTERY
- MCC of EPIDEMIC DYSENTERY
Common cause of UTI and nosocomial infections
can cause STAGHORN CALCULI
Proteus mirabilis
Proteus mirabilis pathogenesis
UREASE hydrolyzes the urea to form AMMONIA
- raise pH – ALKALINE URINE
- encourage the formation of STRUVITE stones - MAGNESIUM AMMONIUM PHOSPHATE
SWEET GRAPE LIKE ODOR
has FLUROSCEIN and PYOCYANIN and PYOVERDIN
grown on CETRIMIDE AGAR
Pseudomonas aeruginosa
MCC of otitis externa
Pseudomonas aeruginosa
VAP
Necrotizing pneumonia
fleur de lis pattern
Pseudomonas aeruginosa
3rd MCC of nosocomial UTI
Pseudomonas aeruginosa
Predominant anaerobe of the human colon
ABDOMINAL ABSCESS PERITONITIS
PERICARDITIS ENDOCARDITIS
CEREBRAL ABSCESS
Bacteroides fragilis
37 y/o woman
hx of UTI
(+) burning on urination + frequency and urgency
urine - smells like ammonia
Proteus mirabilis
27 y/o woman fever, anorexia, headache, weakness diarrheal illness - 36 hrs temp - 39 C HR - 68 bpm BP - 120/80 RR - 18
(+) rose spots
Salmonella enterica subspecies enterica serotype Typhi (Salmonella typhi)
O ANTIGEN 139 (O139)
18 y/o student
(+) abdominal cramps and diarrhea
MacConkey agar - gram (-) rods
Triple Sugar Iron Agar - screen isolates for salmonellae and shigellae
A result suggesting one of these pathogens would be
A. production of urease
B. motility in the medium
C. inability to ferment lactose and sucrose
D. fermentation of glucose
C. inability to ferment lactose and sucrose
43 y/o man
(+) diabetis, (+) non healing wound
Culture: Staphylococcus aureus, Bacteroides fragilis, gram (-) bacillus that SWARMS across the blood plate agar covering the entire surface of the agar after 36 hrs.
The gram (-) is a member of the genus
Proteus
The MC pathogen isolated from patients who have been HOSPITALIZED > 1 week.
A frequent cause of nosocomial infections
Pseudomonas aeruginosa
PSEUDOMONAS
Pneumonia, pyocyanin Sepsis Ecthyma gangrenosum UTIs Diabetes Osteomyelitis Mucoid Polysaccharide capsule Otitis externa Nosocomial infections Exotoxin A Skin infections
A sputum culture of a patient w/ cystic fibrosis grows Pseudomonas aeruginosa that form very mucoid colonies
The implication of this observation is
P. aeruginosa have formed a biofilm in the patient’s airway
The mechanism of action of exotoxin A of Pseudomonas aeruginosa
block the elongation factor 2 (EF 2)
Long term carriage and shedding is most likely to occur after GIT infection w/ which of the ff species?
A. E. coli B. Shigella dysenteriae C. Vibrio cholerae D. Campylobacter jejuni E. Salmonella typhi
E. Salmonella typhi
63 y/o, visited oyster restaurant and ate 2 dozen oysters
2 days later - abrupt onset of chills, fever and light headedness
(+) erythematous skin lesions – hemorrhagic bullae – ulcers
Vibrio vulnificus
Bacteremia associated w/ GIT infection
Campylobacter jejuni
