Gram negative rods Flashcards

Question

Nosocomial means?

Answer 1

disease originating from a hospital

Answer 2

* Slow Lactose Fermenters * Gram negative rods * Not dominant pathogen for any condition * often resistant to many Abx

Answer 3

* Can be found in normal gut flora * Gram negative sepsis (with other GN bugs)

Answer 4

* GN rod * produce diistinctive red colonies (red pigment) * Catalase positive * Hospital outbreaks of UTIs; contaminated water, soap, IV solutions * Sometimes osteomyelitis in IV drug users (also Pseudomonas)

Answer 5

Citrobacter & Serratia

Answer 6

* Salmonella typhi * Salmonella Enterica * Salmonella Enteritidis

Answer 7

* Salmonella typhi -\> typhoid fever * Non-typhoid strains cause gastroenteritis (enterica, enteritidis) * NVcramps, bloody diarrhea * ingestion of contaminated meat, eggs, poultry * osteomyelitis in sickle cell patients

Answer 8

* Flagellated, mobil, encapsulated gram negative rod * disseminate through blood * osteomelitis in sickle cell pts * Live in GI tract of mammals, birds and reptiles * produce hydrogen sulfide * triple sugar iron (TSI) test -\> media turns black * differentiates from shigella * Invades GI mucosa * The cellular response is largely monocytes

Answer 9

* caused by Salmonella typhi * Travelers to Asia, Africa, South America * Classic features * Rose spots * Faint salmon-colored macules * Trunk and abdomen * Pulse-termperature dissociation * High fever -\> slow pulse * Can remain in the gall bladder (carrier state) * endemic countries 1-4% people may be carriers * May be risk factor for carcinoma

Answer 10

* Culture (stool, blood (typhoid))

Answer 11

Gastroenteritis * Fluids/electrolytes * Abx not really helpful (only in severely ill) * has lots of resistance * Anti-peristalsis contraindicated because prolong illness

Answer 12

* Ceftriaxone * Fluoroquinolones * Typhoid vaccine is available * inactive variant given orally * used for high risk travelers

Answer 13

* non-motile (no flagella) * not normal GI flora * Commin in children * Dx: stool culture * Invades mucosal cells (M cels in Peyer's Patches) * Macropinocytosis * Induces apoptosis * Spreads from cell-to-cell * does not spread hematogenously (salmonella does) * Releases Shiga toxin * but non-toxin strains **still** cause disease * Cellular invasion **more** important mechanisms of disease * Very few bacteria are required to cause disease (few as 10) * Cellular response is largely PMNs (neutrophils)

Answer 14

* Fluids/electrolytes * Abx improve symptoms, reduce shedding in stool * can limit spread * Ceftriaxone or Ciprofloxacin

Answer 15

* Salmonella * Produces H2S so black color on triple sugar iron TSI * Mostly Monocyte response * Hematogenous spread * No antibiotics * Motile (flagella) * Shigella * No H2S * Mostly Neutrophil response * Cell-to-cell spread (Macropinocytosis) * Yes Abx (Ceftriaxone or Ciprofloxacin) * Nonmotile * Shiga toxin * Low infectious dose

Answer 16

* Rare cause of UTIs * "Swarm phenotype" * long flagella * facilitates urinary ascent * Bulls-eye on agar plates * Produces urease * converts urea to ammonia * Associated with Struvite Kidney Stones

Answer 17

* highly-feared bacteria * serious hospital acquired infections (i.e. VAP "Ventilator Acquired Pneumonia) * Resistant to many Abx * Obligate aerobe * gram negative rod * Loves the water (commonly found in environmental water sources * Produces blue-green pigment (pyocyanin) * smooth, fluorescent green colonies on culture media * sweet grape-like odor

Answer 18

* Pneumonia (Nosocomial) (Cystic fibrosis) * UTIs * Surgical wound infections * Bacteremia/sepsis * Osteomyelitis (IV drug users) * Ottitis externa (swimmers ear) * Burn infections * Hot tub folliculitis

Answer 19

* Endotoxin (LPS) * can cause fever, shock * Endotoxin A * Inactivates elongation factor EF-2 * EF-2 is necessary for protein synthesis

Answer 20

* classic pneumonia in CF pts

Answer 21

tender itchy papules after using hot tub or spa

Answer 22

* Swimmer's ear * painful ear with discharge

Answer 23

* IV drug users

Answer 24

* Caused by Pseudomonas bacteremia * Black, necrotic ulcers on skin with bacteremia * invasion/destruction of blood vessels by bacteria * Classic case is neutropenic cancer patient with fever, chills (bacteremia) who develops black lesions on chest and back

Answer 25

* Gram negative rod similar to Pseudomonas * Oxidase positive * Catalase positive * Rare cause of infections in * Cystic fibrosis * Chronic Granulomatous Disease

Answer 26

* gastritis & ulcers * common in paitents with ulcers (majority of duodenal ulcers) * many with gastric ulcers * MALT lymphoma * mucosal associated lymphatic tissue lymphoma * B-cell cancer; usually in the stomach * Highly associated with H. pylori

Answer 27

* Causes gastritis and ulcers (abdominal pain) * Urease positive * hydrolyzes urea to compounds that damage epithelium * produces ammonium (alkaline) (protects from acidic environment in stomach * Protects bacteria from stomach acid * Urea breath test * patients swallow urea with isotopes (carbon-14 or Carbon-13) * detection of isotope labled carbon dioxide in exhaled breath is evidence indicating urea was split (urease is present)

Answer 28

* Biopsy * Urea breath test * Stool antigen

Answer 29

* Triple therapy for 7-10 days * Proton pump inhbitor (omeprazole) * Clarithromycin * Amoxicillin or Metronidazole * Test to determine eradication (failure in 20% of attempts) * breath test, stool antigen or biopsy

Answer 30

* Does not gram stain well * silver stains used * special culture requirements * Buffered charcoal Yeast Extract (BCYE) with Iron and Cysteine added for growth * Supplemented with antibiotics and silver dyes * Antimicrobials prevent overgrowth by competing organisms * dyes give distinctive color to Legionella

Answer 31

* Nosocomial pneumonia in Nursing homes *

Answer 32

* initially mild pneumonia symptoms * fever; mild, slightly productive cough * can progress to severe pneumonia * GI symptoms * NVwD, abdominal pain * Hyponatremia (Na\<130 mEq/L) common * can occur in any pneumonia but more common with Legionella Pneumonia

Answer 33

* Mild cough * Watery diarrhea * Confusion (low Na) * Negative bacteria on gram stain (poorly visualized)

Answer 34

* Fluoroquinolone * or * Macrolide

Answer 35

Mild form of Legionella infection * fever * malaise * chills * fatigue * headache * no respiratory complaints * Chest radiograph usually normal

Answer 36

* Gneg rod anaerobic * normal GI flora * cause infection after breach of mucosal barrier

Answer 37

* rare to cause infections by itself * Usually part of polymicrobial infections from the GI tract * peritonitis (following perforation) * Intraabdominal abscess * Lung abscess (aspiration) * E. coli/GNR and B fragilis often components together

Answer 38

* Covered by Metronidazole * Common GI therapy: Cipro/Flagyl * Quinolone for E. coli * Metronidazole for B. fragilis