Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

TCM Exam 2 > Gram Negative Bacteria > Flashcards

Gram Negative Bacteria Flashcards

1
Q

Gram Negatives

A

thinner peptidoglycan layer much thinner and sandwiched between an inner cell membrane and a bacterial outer membrane.

The alcohol degrades the outer membrane; incapable of retaining the violet stain

Outer membrane contains lipopolysaccharide (LPS) endotoxin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Neisseria

A

Gram-negative “coffee bean” diplococci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

N. gonorrhoeae

A

Gram-negative “coffee bean” diplococci

fimbriae (pili)

LPS endotoxin

and transmission is via sexual contact or vaginal delivery
–>Gonorrhea

associated with pelvic inflammatory disease (PID) –> sterility

Causes conjunctivitis in neonates (opthalmia neonatorum)

Dx- urethral exudate containing gram (-) negative intracellular diplococci,

Thayer-Martin VCN lysed RBC media

Historically used penicillin and quinolones but now have resistance to both.

Can cause sepsis with C5-C9 deficiencies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

N. meningitidis

A

(meningococcus)

antiphagocytic capsule

Meningococcal endotoxin LPS is toxic (hemorrhage/petichiae and sepsis)

High rates of infection in complement deficiencies C5-C9
Meningitis

DX- CSF on Thayer-Martin VCN media and PCR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Moraxella & Kingella

A

Gram-negative diplococcus

Moraxella catarrhalis
common cold, otitis media and sinusitis
resistant to beta-lactams

Moraxella lacunata conjunctivitis

Kingella kingae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Coliforms

A

Gram-negative bacilli that resemble Escherichia coli
Oxidase negative
Ferment lactose (except proteus and serratia)

Many can produce H2S

E. coli, proteus, serratia, klebsiella and enterobacter may produce urinary tract infections
E. coli - 85% of urethrocystitis cases, 80% of chronic bacterial prostatitis cases and 90% of acute pyelonephritis
E. coli - diarrheas
Proteus responsible for renal infection with staghorn calculi (urease and subsequent alkalization and supersaturation of urine)

K. pneumoniae responsible for 3% of bacterial pneumonia cases

also often Nosocomial or hospital-acquired infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Escherichia

A

Gram negative bacilli
Ferment lactose

E. coli with K1 antigen (provides the organism with an increased resistance to phagocytosis and the action of complement) - propensity for producing neonatal meningitis

Urinary tract infections via fecal material contamination

Pathogenic diarrheal E. coli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Pathogenic diarrheal E. coli (4 types)

A

Enterotoxigenic
= traveler’s diarrhea. ST heat stable and LT heat labile

Enteroinvasive = shigella-like diarrhea. Bloody stool, shiga-like toxin destruction of cells

Enteropathogenic –> infantile diarrhea, salmonella-like

Enterohemorrhagic = hemorrhagic colitis, grossly bloody stool. 0157:H7, shiga-like cytotoxins (“verotoxins”)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Klebsiella

A

Gram-negative bacilli
Ferment lactose (reddish on McConkey’s agar)
Encapsulated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

K. pneumoniae

A

Most common cause of nosocomial respiratory tract infections
Bacterial pneumonia
Urinary tract infections

(exams like to say looks like red jelly sputum)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

K oxytoca

A

can cause colitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Klebsiella granulomatis

A

–> granuloma inguinale (donovanosis) = painless genital ulcers –> scarring with lymphatic blockage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Enterobacter

A

Gram-negative rods
Ferment lactose
Possess inducible beta-lactamases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Enterobacter cloacae

A

Normal gut flora
Sometimes causes lower respiratory tract, urinary tract and intra-abdominal infections

nosocomial outbreaks (surgical equipment, etc.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Enterobacter aerogenes

A

Nosocomial opportunistic infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Serratia

A

Gram-negative rod
Non-lactose fermenter, but red on MacConkey agar
Prodigiosin - characteristic red pigment

S. marcascens- hospital-acquired infections (common respiratory and urinary tracts; associated with catheters)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Proteus

A

Gram-negative bacilli
Non-lactose fermenting**

cause urinary tract infections,
wound infections

Proteus mirabilis
Swarming motility (very motile)
Urease alkalinizes urine –>struvite stones

Proteus vulgaris & Proteus penneri

18
Q

Shigella

A

Shigella is negative everything:

Gram-negative rod
Non-lactose fermenting
Do not produce H2S
Non-motile

Shiga toxin (A subunit inhibits 60s ribosome and protein synthesis)

19
Q

Shigella dysenteriae

A

bacillary dysentery

cramps and a watery, bloody diarrhea

Other species of Shigella produce milder diarrheal disease

Rx - fluid with electrolytes as most infections are self limited

20
Q

Salmonella

A

Gram-negative bacilli
Non- lactose fermenting
Produce H2S (from ferrous sulfate in media) –> black colonies. Distinguishes it from shigella.

Facultative intracellular parasite

2 species [S. bongori and S. enterica (which has 6 subspecies)]

“Vi” or capsular antigen

by oral ingestion of the bacteria via contaminated food (poultry), water

Activation of adenylate cyclase –> diarrhea

Septicemia - may be caused by any species but S. enterica enterica serovar Choleraesuis common

rx– no antibiotic needed for enteritis, but 3rd gen cephalosporins or quinolones for salmonella

21
Q

Salmonella enterica enterica, serovar Enteritidis

A

Enteroinvasive gastroenteriti

after 1-3 day incubation, usually self-limited

22
Q

S. enterica enterica, serovar Typhi

A

Enteric (typhoid) fever – after 10-14 days incubation, bacteria leave the intestine and multiply within lymphoid tissues and later get intestinal symptoms, may mimic appendicitis

23
Q

Pseudomonas

A

Gram negative RODS
Oxidase-positive
Nonfermentative

green colonies

Antiphagocytic exopolysaccharide (alginate) slime biofilm

produce pigments (fluorescent pyoverdin and pyocyanin)

Exotoxin A is most toxic, mechanism identical to diphtheria toxin)

an opportunistic pathogen

bacterial vasculitis

produces skin lesions known as ecthyma gangrenosum

commonly present in lungs of patients with cystic fibrosis

hot tub folliculitis

24
Q

Burkholderia

A

Gram-negative rods
Oxidase-positive

Burkholderia cepacia- in cystic fibrosis

Burkholderia pseudomallei (melioidosis)

25
Q

Stenotrophomonas maltophilia

A

Gram-negative rod
Most non-fermentative
Oxidase +/-

immunocompromised patients

26
Q

Legionella

A

Gram-negative bacilli

ubiquitous aquatic

Several species produce hemolysins and there are some reports of exotoxins

multiply within macrophages (intracellular pathogen)

L. pneumophila

  • Legionnaires’ disease
  • Pontiac fever

dx- charcoal yeast extract agar

prevention: - regular maintenance of air conditioning

27
Q

Fusobacterium

A

Gram-negative fusiform BACILLI
Anaerobic

F. necrophorum
- peritonsillar abscesses

Produces hemagglutinin which leads to septic thrombophlebitis of internal jugular vein (Lemierre syndrome)

Dx – anaerobic cultures, PCR

28
Q

Main Vibrio types

A

V. parahaemolyticus

V. vulnificus

V. cholerae, toxigenic 01 (travel)

29
Q

Vibrio cholerae

A

Gram negative “curved” rods with single polar flagellum; “vibrate”
Oxidase +

a disease of poor sanitation (water with human fecal contamination)

Potent enterotoxin choleragen

–> overproduction of cyclic AMP

“rice water stool”

dx– fluid and electrolyte replacement

30
Q

Campylobacter jejuni

A

Gram-negative curved rods (Greek “campylo“ = curved)
Non-lactose fermenter

LPS endotoxin

Ingestion of contaminated water, milk or undercooked foods (raw clams)

31
Q

Helicobacter pylori

A

Gram-negative helically shaped
Non-lactose fermenter

Lives in the mucus layer above the gastric epithelium and produce urease

Associated with chronic gastritis, gastric and duodenal ulcers, gastric adenocarcinoma and gastric MALT lymphoma

Feco-oral or oral-oral transmission
rx- clarithromycin-based triple therapy or bismuth quadruple therapy

32
Q

Bacteroides

A

Gram-negative bacilli or cocco-bacilli

Anaerobic (obligate)

B. fragilis has an anti-phagocytic capsule

Opportunistic with immunosuppression

dx- Opportunistic with immunosuppression

33
Q

Prevotella

A

Prevotella sp. are similar to, and previously classified as, bacteroides
Part of the normal oral and vaginal flora
Can cause obstetric and gynecologic infections, aspiration pneumonia, chronic otitis media and sinusitis, and abscesses in lung, oral cavity, brain abscesses, and human bite wounds

34
Q

Acinetobacter baumannii

A

Gram-negative coccobacillus

Nosocomial infections

35
Q

Haemophilus

A

Gram-negative coccobacilli

Capsule is major virulence determinant

H. influenzae type b - most common cause of bacterial meningitis in children 6 months-2 years

H. ducreyi –chancroid (soft chancre)
H. parainfluenzae - pneumonia, endocarditis
H. aegypticus -conjunctivitis

prevention: Hib vaccine

36
Q

Bordetella

A

Gram negative coccobacilli
Encapsulated
several exotoxins: filamentous hemagglutinin, pertussis toin, invasive adenylate cyclase toxin, tracheal cyotosxin, lethal (dermonecrotic) toxin

B. pertussis - whooping cough: catarrhal stage, paroxysmal phase, convalescent phase

prevention: DTaP vaccine x 5 followed by Tdap in adulthood

37
Q

Yersinia

A

Gram negative, bipolar staining coccobacilli
Non-lactose fermenter
Glucose fermenter

Y. enterocolitica and Y. pseudotuberculosis
intestinal parasite of animals causing disease via ingestion of contaminated food or water
self-limited ileitis, gastroenteritis

Y. pestis 
Bubonic plague (black death) maintained among rodent populations (ground squirrels, prairie dogs, great gerbils/black rats

Two antiphagocytic components
F1 antigen and the V & W antigens (both required for virulence

Bubonic plague
Septicemic plague
Pneumonic plage

Prevention: - Vector control and inactivated Y. pestis vaccine for lab personnel handling organism

38
Q

Francisella tularensis

A

Gram-negative pleomorphic coccobacillus

Intracellular pathogen

Tularemia

Ulceroglandular via handling rabbits

Pneumonic

39
Q

Brucella

A

Gram negative coccobacilli

Intracellular parasites

Generally zoonosis via occupational exposure to infected animal
Outbreaks via ingestion of unpasteurized milk products and undercooked meat

B. melitensis – goat, sheep, camels
Unpasteurized milk caused Malta/undulant/Mediterranean fever
B. suis - pigs

Brucellosis
Undulant fever

B. melitensis and B. suis are more transmissible to humans

40
Q

Pasteurella multicida

A

Gram-negative coccobacilli

from lots of animals, but in the class example the cat!

TCM Exam 2 (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions