Brainscape's Knowledge GenomeTM

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


See full index

M (ASCP) > Bacteriology > Flashcards

Bacteriology Flashcards

1
Q

Characteristics of Enterobacteriaceae

A

Gram negative bacilli
Grow on MacConkey
Ability to ferment glucose
Oxidase negative
Reduce nitrates to nitrites

Also found free living in the environment and as natural inhabitants of the intestinal tract of humans and animals

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

E. coli

A

Causes UTI, septicemia, neonatal sepsis and meningitis, and diarrhea
Lactose positive, indole positive, MR positive, motility positive
H2S negative, VP negative, citrate negative, urease negative
Predominant aerobe in GI tract
Green metallic sheen on EMB
Gray colonies on BAP, A/A and gas on TSI, LF on MAC, yellow on HE, yellow on XLD

E. coli O157:H7 causes enterohemorrhagic diarrhea - clear colonies on MACSORB because it does not ferment sorbitol

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

Klebsiella

A

Causes pneumonia, UTI, and septicemia
Highly mucoid colonies on all media
LF on MAC, A/A and gas on TSI, yellow on HE, yellow on XLD
VP positive, citrate positive, lactose positive, urease positive
H2S negative, indole negative (usually), MR negative, motility negative, ornithine decarboxylase negative

K. oxytoca - indole pos
K. pneumoniae - indole negative

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

Serratia

A

Opportunistic pathogen that causes pneumonia and septicemia in immunosuppressed people
Bright red colonies on some media
K/A on TSI, slow LF on MAC, colorless on HE, yellow or colorless on XLD
VP positive, citrate positive, motility positive
Lactose negative, H2S negative, indole negative, urease negative

S. marcescens - lysine pos, ornithine pos
S. liquefaciens - lysine neg, ornithine neg

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

Proteus

A

Causes UTI, wound infections, and septicemia
Swarms and smells like chocolate cake
NFL on MAC (doesn’t grow well on MAC in general), colorless on HE, yellow or colorless with or without black centers on XLD
H2S positive, MR positive, urease positive, motility positive
Lactose negative

P. vulgaris - indole pos (Vulgaris Indole Positive), A/A on TSI
P. mirabilis - indole neg, K/A on TSI

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

Providencia

A

Causes UTI and diarrhea
Indole positive, MR positive, citrate positive, motility positive
Lactose negative, H2S negative, VP negative
K/A on TSI, NLF on MAC, colorless on HE, yellow or colorless on XLD

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

Morganella

A

Mainly nosocomial infections including UTI and wound infections
Similar to Proteus but non swarming
Indole positive, MR positive, weakly urease positive
Lactose negative, H2S negative, VP negative, citrate negative

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

Citrobacter

A

Causes nosocomial infections
H2S positive, MR positive, citrate positive (duh), motility positive, ONPG positive
VP negative, lysine decarboxylase negative
Slow lactose fermenter on MAC
Clear colonies on SS and HE

C. freundii - indole neg
C. koseri - indole pos

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

Yersinia

A

Causes diarrhea (enterocolitica) and plague (pestis)
MR positive, urease positive
Lactose negative, H2S negative, VP negative, citrate negative
Gram negative coccobacilli with bipolar staining
Grow “bulls-eye” colonies on CIN agar

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

Shigella

A

Causes dysentery (shigellosis)
Most communicable of bacterial diarrheas
Found primarily in crowded or substandard conditions (day-cares, jails/prison, etc.)
MR positive
Lactose negative, H2S negative, VP negative, citrate negative, urease negative, motility negative
Clear colonies on MAC and HE

S. dysenteriae is the most severe form
S. sonnei is the most common form
Serogrouped by O antigens (A, B, C, and D)
Closely related to Escherichia on a molecular basis

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

Edwardsiella tarda

A

Opportunistic pathogen
Causes bacteremia and wound infections
H2S positive, indole positive, MR positive, motility positive
Lactose negative, VP negative, citrate negative, urease negative
Clear on MAC

Chief reservoirs are reptiles and fresh water fish
Infections often involve aquatic environments

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

Salmonella

A

Causes typhoid fever, bacteremia, and enterocolitis
H2S positive, MR positive, motility positive, lysine decarboxylase positive
Lactose negative, indole negative, VP negative, urease negative, ONPG negative
Clear colonies on MAC and black colonies on HE

Found in poultry and can be transmitted by reptiles (bearded dragons specifically)
S. typhi has Vi antigen
Grouped by O antigens (A, B, C) and serotyped by H antigens (1 and 2)

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

Enterobacter

A

Opportunistic pathogen that causes nosocomial infections
UTI, RTI, and wound infections
Mucoid colonies on all plates
Has same IMViC reactions as Klebsiella
Lactose positive, VP positive, citrate positive, motility positive, ornithine decarboxylase positive
H2S negative, indole negative, MR negative

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

Aerotolerance testing

A

Aerobe: grows aerobically on blood and on chocolate agar in CO2 incubator
Capnophilic aerobe: only grows on chocolate agar in CO2 incubator
Facultative anaerobe: grows aerobically on blood, anaerobically on blood, and on chocolate agar in CO2 incubator
Obligate anaerobe: only grows on blood anaerobically
Aerotolerant anaerobe: grows anaerobically on blood and on chocolate agar in CO2 incubator

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

Organisms that require increase CO2 for incubation

A

Campylobacter
Haemophilus
Helicobacter
Moraxella catarrhalis
Mycobacterium
Pathogenic Neisseria

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

Hemolysis reactions on blood agar

A

Alpha: green/brown zone around colony, partial lysis of RBCs (strep pneumo)
Beta: clear zone around colony, complete lysis of RBCs (Group A strep)
Gamma: no zone of hemolysis, no lysis of RBCs

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

Staphylococcus spp

A

Gram positive cocci, typically in clusters
Smooth, convex, opaque colonies on BAP
Catalase positive, bacitracin resistant
Normal flora of the skin, mouth, pharynx, vagina, urethra, and GI tract
Facultative anaerobe
Grows on nonselective media
Salt tolerant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

S. aureus

A

Gram positive cocci, usually in clusters
Typically beta hemolytic and colonies are tan/golden
Coagulase positive
Ferments mannitol (yellow colonies on Mannitol salt agar)
Contains protein A (virulence factor that inhibits phagocytosis)
Can produce exfoliative toxin (causes detachment of granulosum layer in the epidermis)
Spread by direct contact
10-60% of people are carriers
85-90% are resistant to penicillin

Causes skin infections (impetigo, furuncles, cellulitis, etc.), scalded skin syndrome, toxic shock syndrome, food poisoning, acute bacterial endocarditis, pneumonia, and osteomyelitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Coagulase negative staphylococci (CONS)

A

Opportunistic pathogen
Common cause of hospital acquired UTI
Gram positive cocci, usually in clusters
White colonies that are usually nonhemolytic
Don’t ferment mannitol (pink on Mannitol salt agar)
Sensitive to novobiocin
Normal flora on skin and mucous membranes
Often contaminant
Usually only speciate if from normally sterile site
50-80% are S. epidermidis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

S. saprophyticus

A

Gram positive cocci, usually in clusters
White to slightly yellow color and nonhemolytic (and smell like dirty socks)
Catalase positive
Coagulase negative
Urease positive
Resistant to novobiocin (only performed when CONS is isolated from urine of females)

Implicated in 10-20% of UTIs, second only to E. coli

Causes UTI (known as “honeymooner’s UTI) and is associated with sexual intercourse and STDs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Micrococcus

A

Usually nonpathogenic
Found in the environment and on skin, mucous membranes, and the oropharynx
Large Gram positive cocci in pairs, tetrads, and clusters
Often pigmented (bright yellow, orange, pink, tan)
Catalase positive, coagulase negative
Susceptible to bacitracin
Not commonly isolated
Must differentiate from staph
Usually only grow aerobically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Streptococcus spp

A

Oval Gram positive cocci in pairs and chains
<1mm in diameter
White to gray color, translucent or semi opaque
Variable hemolysis reactions
Catalase negative
Facultative anaerobes
Require enriched media with chaining occurring best in broth media

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Group A streptococcus (S. pyogenes)

Pyogenic - capable of causing local purulent inflammation or generalized infection, S. pyogenes is named for this characteristic

A

Oval Gram positive cocci in chains
Grayish-white pinpoint colonies
Usually beta hemolytic with a wide zone
Catalase negative
Sensitive to bacitracin
PYR positive
Hemolysis due to streptolysin S and O (Oyxgen-labile exotoxin that is released)
Can have a hyaluronic acid capsule (helps the organism resist phagocytosis)
Produces DNase (breaks down DNA that allows it to infect pharygeal tissue and skin)
Produces sterokinase (enzyme that inhibits the coagulation cascade, preventing clot formation and allows organism to spread throughout the body)
Produces exotoxin A (virulence factor that decreases the production of antibodies)

Causes skin infections (impetigo, cellulitis), pharyngitis, scarlet fever, toxic shock syndrom, toxic shock-like syndrome, and necrotizing fasciitis
If not treated right away can progress into rheumatic fever and acute glomerulonephritis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Group B streptococcus (S. agalactiae)

A

Normal flora of female genital tract
Oval Gram positive cocci in chains
Slightly larger colonies than GAS
Gray-white color with a narrow zone of beta hemolysis
Can also be nonhemolytic
Catalase negative
PYR negative
Resistant to bacitracin
Sodium hippurate positive
CAMP test positive
Forms a polysaccharide capsule to enhance its ability to cause disease
Vaginal and rectal swabs collected from pregnant women at 35-37 weeks gestation (positive individuals can then receive prophylactic IV penicillin during delivery)
Inoculated in selective broth (LIM or carrot) and plated to BAP after 24 hours

Most common cause of serious infections in infants (including pneumonia, meningitis, and sepsis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Group D streptococcus (not enterococcus)

A

Normal in GI tract
Causes nosocomial UTI, wound infections, and bacteremia
Oval Gram positive cocci in chains
Usually nonhemolytic but can be alpha
Esculin positive
Most common S. gallolyticus (used to be S. bovis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Enterococcus

A

Normal in mouth, GI tract, female genital tract
Oval GPC in pairs and chains
Usually alpha or nonhemolytic, rarely beta
Catalase negative
Esculin positive, PYR positive, LAP positive
Can grow in 6.5% NaCl
Lancefield group D
Intrinsically resistant to beta lactam antibiotics and are penicillin resistant
Can become resistant to vancomycin
80% are E. faecalis, 15% are E. faecium

Causes UTI, subacute endocarditis (following a severe enterococcal UTI)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Streptococcus pneumoniae

A

Normal in upper respiratory tract of some
Lancet shaped Gram positive diplococci, frequently encapsulated
Polysaccharide capsule inhibits phagocytosis
Round, translucent, dome shaped colonies
Catalase negative
Alpha hemolytic
Bile solubility positive
Sensitive to optochin
Positive Quellung reaction (capsule visualization)
Releases IgA proteases (enzyme the cleaves IgA and increases pathogenicity)
No Lancefield group
>80% serotypes based on capsular antigens
Patients produce a rusty colored sputum which is indicative of Strep pneumo

Causes pneumonia (hence the name), meningitis, otitis media (middle ear infection), sepsis in patients with Sickle cell anemia and who are post-splenectomy, and sinusitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Viridans streptococcus

A

Normal in oral, respiratory, GI mucosa
Opportunistic pathogens
Frequently cause of subacute bacterial endocarditis
Gingivitis and dental cavities
Gram positive cocci in chains
Usually alpha hemolytic but can be beta or nonhemolytic
Catalase negative
Resistant to optochin
Bile solubility negative
Certain strains (S. sanguis and S. mutans) may produce extracellular polysaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Microaerophilic Streptococcus spp (formerly S. milleri group)

A

Normal flora of mouth and GI/GU tracts
Infections associated with trauma or surgery
Most common sites are abdomen, head, and neck
Gram positive cocci in pairs and chains
Colonies are half the size of other strep
Usually beta hemolytic but can be alpha or nonhemolytic
Butterscotch or caramel odor
Usually Lancefield group F
PYR negative, VP positive
3 species - S. anginosus, S.constellatus, S. intermedius
Grow better anaerobically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Bacillus spp

A

Usually contaminants
Gram positive rods
Large spreading beta hemolytic colonies with irregular edges (Medusa head)
Whitish gray but can be pigmented
Catalase positive
Motile (usually)
Must rule out B. anthracis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Bacillus anthracis (Anthrax)

A

One of the most highly pathogenic microorganisms
Contracted from contaminated hides, wool, and meat
Very rare in the United States
Large Gram positive rods with square ends, may be in chains
Oval central to subterminal spores that aren’t swollen
Looks like bamboo
Spores may not be seen in direct smear
Large adherent, nonhemolytic, flat to slightly convex colonies with irregular borders
Ground-glass appearance
Stands up like beaten egg white when touched with a loop
Catalase positive
Nonmotile
Potential bioterrorism organism
Handle in BSC
Submit to public health lab for confirmation

Helps rule out B. anthracis from B. cereus/other Bacillus spp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Bacillus cereus

A

Often environmental contaminant
Can cause local and systemic infections and food poisoning
Large Gram positive rods with square ends
Oval central to subterminal spores that aren’t swollen
Looks like bamboo
Large, adherent, beta hemolytic, flat to slightly convex colonies with irregular borders
Ground-glass appearance
Stands up like beaten egg white when touched with a loop
Motile
2nd most important pathogen in the genus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Corynebacterium spp

A

Normal on skin and mucous membranes
Opportunistic pathogens
Irregular, slightly curved Gram positive rods, nonparallel sides, club shaped ends
“Chinese letters” or palisades
Facultative anaerobe
Grows on most media
Catalase positive
Nonmotile
Called diphtheroids because they resemble C. diphtheriae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Corynebacterium diphtheriae

A

Cause of diphtheria
Rare in the United States
Irregular, slightly curved Gram positive rods, nonparallel sides, club shaped ends
“Chinese letters” or palisades
Gray-black colonies with brown halos on Tindale agar
Black colonies on cystine tellurite
Loeffler medium stimulates growth and production of metachromatic granules
Catalase positive
Nonmotile
Toxin producing
Identification requires demonstration of toxin production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Corynebacterium jeikeium

A

Hospital acquired pathogen
Irregular, slightly curved Gram positive rods, nonparallel sides, club shaped ends
“Chinese letters” or palisades
Catalase positive
Rapid sucrose urea negative
Most commonly isolated diphtheroid
Highly resistant to antibiotics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Listeria monocytogenes

A

Meningitis and septicemia in newborns and immunocompromised people
Common cause of food poisoning from deli meat and soft cheese
Gram positive rods with parallel sides and rounded ends
Arranged as singles, chains, or diphtheroid arrangements
Tiny colonies with narrow zone of indistinct beta hemolysis
Translucent and gray
Catalase positive, hippurate hydrolysis positive, esculin positive, CAMP positive
Tumbling motility on wet mount
Umbrella growth in motility agar at RT but no at 35 degrees C
Grows from 0.5-45 degrees C
Cold enrichment may be used
Catalase differentiates from Group B strep
Motility differentiates from diphtheroids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Nocardia

A

Causes skin infections in immunocompetent people and invasive pulmonary and disseminated infections in immunocompromised people
Gram positive rods with fine branching filaments and fragmentation
Often look beaded
Very slow growing
Wrinkled, dry, chalky white appearance on BAP
Beta hemolytic
Catalase positive
Partially acid fast
N. brasiliensis most common species to cause skin infections
N. asteroides most common species to cause lung infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Neisseria spp

A

Gram negative diplococci
Squished together to make a coffee bean shape
Aerobic or facultative
Pathogens are capnophilic
Catalase positive, oxidase positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

N. gonorrhoeae

A

Causes gonorrhea, salpingitis, and ophthalmia of the newborn
Intracellular and extracellular Gram negative diplococci
Diagnostic in urethral discharge from symptomatic males
Culture confirmation required for females
Grows on CHOC and Neisseria selective agars
Colonies are small, grayish-white or tan
Five different colony types so it could end up looking mixed
Utilizes only glucose
Susceptible to drying and cold
DO NOT REFRIGERATE
Culture is preferred for non-genital specimens and those from children
Should confirm by different method (PCR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

N. meningitidis

A

Can be normal flora of the upper respiratory tract
Common cause of meningitis in young adults
Intracellular and extracellular Gram negative diplococci
Grows on BAP, CHOC, and Neisseria selective media
Colonies are bluish gray or tan
May be mucoid
Utilizes both glucose and maltose
ONPG negative
Handle in BSC
Serogrouping by slide agglutination
Bacterial antigen test available for detection but poor sensitivity and shouldn’t replace a culture
Vaccine is available

41
Q

Commensal Neisseria spp

A

Normal in upper respiratory tract
Rarely causes disease
Gram negative diplococci
Grows on BAP and CHOC at RT
Grows on nutrient agar at 35 degrees C
Not speciated if from respiratory specimens
Must differentiate from pathogenic Neisseria when isolated on selective media or from normally sterile body site

42
Q

N. lactima

A

Normal in upper respiratory tract of children
Rare in adults
Rarely causes disease
Gram negative diplococci
Will grow on Neisseria-selective media
Resembles N. meningitidis but smaller
Utilizes glucose, maltose, and lactose
ONPG positive
Easily misidentified as N. meningitidis (ONPG used to differentiate)

43
Q

Moraxella catarrhalis

A

Normal in upper respiratory tract
Causes respiratory infections in young, old, and compromised people
Causes otitis media and sinusitis in children
Gram negative diplococci
Grows on BAP and CHOC at RT
“Hockey puck” colonies (can be pushed around the agar with a loop)
Catalase positive, oxidase positive
No carbohydrate utilization
ONPG negative
DNase positive and butyrate positive (differentiates from Neisseria spp)

44
Q

Antigens of Enterobacteriaceae

A

O antigen: somatic antigen - located in the cell wall, heat stable lipopolysaccharide, used for serological grouping of Salmonella and Shigella
H antigen: flagellar antigen - located in the flagella (duh), heat labile proteins, used to serotype Salmonella
K antigen: capsular antigen - located in the capsule (duh), heat labile polysaccharide that can mask the O antigen, prevents phagocytosis to increase virulence

45
Q

Enterohemorrhagic E. coli (EHEC)

A

Also known as Shiga toxin-producing (STEC) or verotoxin-producing (VTEC)
Causes diarrhea, hemorrhagic colitis, hemolytic uremic syndrome (HUS)
Most common cause of renal failure in children in the US
May be fatal, especially in young or elderly patients
Transmitted through undercooked meat, raw milk, and unpasteurized apple juice/apple cider
Disease mechanism is toxin (Shiga or verotoxin)
GMST will show RBCs but no polys

46
Q

Enterotoxigenic E. coli (ETEC)

A

Causes “traveler’s diarrhea” and diarrhea in infants
Transmitted by contaminated food or water
Disease mechanism is toxins
GMST will show no polys or RBCs

47
Q

Enteroinvasive E. coli (EIEC)

A

Causes dysentery-like blood diarrhea in young children in areas of poor sanitation
Transmitted through contaminated food or water
Disease mechanism is invasiveness
GMST will show polys, RBCs, and mucus

48
Q

Enteropathogenic E. coli (EPEC)

A

Causes diarrhea in infants
Major pathogen in infants in developing countries
Transmitted through formula and food contaminated with fecal material
Disease mechanism is adherence/attachment
GMST will show no polys or RBCs

49
Q

Enteroaggregative E. coli (EAEC)

A

Causes diarrhea in developing countries and chronic diarrhea in HIV-infected patients
Nosocomial and community acquired transmission
Disease mechanism is adherence/attachment
Most labs cannot detect this pathogen

50
Q

Diffusely Adherent E. coli (DAEC)

A

Causes diarrhea and UTI that is most common in children in developing countries
Not much known about route of transmission
Disease mechanism is adherence/attachment
All together not well studied pathogen

51
Q

Characteristics of nonfermenting Gram negative rods

A

Obligate aerobes
Don’t ferment carbohydrates (K/K on TSI)
May be oxidizers or non-oxidizers
Oxidation-fermentation media: either open tube pos/closed tube neg (oxidizer) or open tube neg/closed tube neg (non-oxidizer)
Grows on BAP and CHOC in 24-48 hours
Most grow on MAC as NLF
Most are oxidase positive
Resistant to a variety of antibiotics

52
Q

Pseudomonas aeruginosa

A

Not usually normal flora
Important cause of nosocomial infections (burns, wounds, RTI, UTI, bacteremia)
Cause of swimmers ear and contact lens keratitis
Long, thin, pale staining Gram negative rod
Flat spreading colonies, beta hemolytic, with a metallic sheen on BAP
Oxidase positive, catalase positive, and grape scented
Can grow at 42 degrees Celsius (other species of Pseudomonas cannot)
Produces pigment pyocyanin

53
Q

Acinetobacter spp

A

Part of normal flora of skin and nasopharynx
Opportunistic pathogen causing nosocomial infections like UTI, pneumonia, septicemia, and meningitis
A. baumannii is the most common species
Pleomorphic Gram negative coccobacilli in singles, pairs, or short chains
Can be confused with N. gonorrhoeae or Moraxella
Can produce purple tinged colonies that get confused with LF
Oxidase negative, catalase positive

54
Q

Stenotrophomonas maltophilia

A

Not part of normal flora
Colonizes immunocompromised and cystic fibrosis patients
Common in hospitals causing nosocomial pneumonia
Straight or slightly curbed slender Gram negative rods in singles or pairs
Large, nonhemolytic colonies with a light yellow pigment on BAP
Agar will have a lavender-green discoloration in areas of heavy growth
Oxidase negative, catalase positive, rapid oxidizer of maltose, weaker oxidizer of glucose
Has an ammonia odor

55
Q

Campylobacter jejuni

A

Most common cause of bacterial diarrhea
Sources include chickens, raw milk, and pets
Faintly staining, “seagull wing” shaped, Gram negative rod
Microaerophilic and capnophilic
Grown on CAMPY BAP at 42 degrees C but can also grow at very low temperatures
Slow growing so plates are held for 3 days
Darting corkscrew motility, oxidase positive. catalase positive, and Hippurate positive
Hippurate hydrolysis is used to speciate

56
Q

Campylobacter coli

A

Similar to C. jejuni, but less severe
Usually foodborne
Rarely differentiated from C. jejuni
Hippurate hydrolysis negative

57
Q

Campylobacter fetus

A

Causes bacteremia in immunocompromised and elderly patients
Most often isolated in blood cultures
Hold plates for 2 weeks and inhibited on CAMPY BAP
Oxidase positive, catalase positive
Hippurate hydrolysis negative

58
Q

Helicobacter pylori

A

Causes gastritis, duodenal and peptic ulcers
Possible risk factor for gastric carcinoma
Curved, slender, Gram negative rod
Grows on nonselective media at 37 degrees C
Rarely cultured
Tested with rapid urease tests on gastric biopsy, urea breath test, histology, PCR, or serology testing

59
Q

Vibrio cholerae

A

Causes cholera (acute diarrhea, dehydration, electrolyte imbalance)
Transmitted by contaminated water and seafood
Uncommon in the US but may be seen in coastal areas
Small comma-shaped Gram negative rods in direct smears
Straight pleomorphic Gram negative rods in culture
Nonhalophilic (doesn’t require NaCl to grow)
Grows as large yellow colonies on TCBS agar (ferments sucrose)
Characteristic “rice water” stools

60
Q

Vibrio vulnificus

A

Second most serious type of vibrio infection
Affects the immunocompromised or individuals with liver disease by causing septicemia following the consumption of raw oysters and water associated wound infections
Affects healthy individuals by causing gastroenteritis
Straight or curved Gram negative rods
Halophilic (requires the addition of Na)
Most are green on TCBS

61
Q

Vibrio parahaemolyticus

A

Causes gastroenteritis from contaminated seafood or water associated wound infections
Straight or curved Gram negative rods
Requires 1% NaCl for growth
Blue-green colonies on TCBS (doesn’t ferment sucrose)

62
Q

Aeromonas spp

A

Causes gastroenteritis and wound infections, often related to aquatic exposure
Can also cause septicemia and meningitis
Straight or curved Gram negative rods
Grows beta hemolytic on BAP, NLF on MAC
Doesn’t grow on TCBS
Oxidase positive

63
Q

Plesiomonas shigelloides

A

Causes gastroenteritis from contaminated water or seafood
Bacteremia and meningitis in immunocompromised and neonates
Pleomorphic Gram negative rods in singles, pairs, short chains, or long filaments
Grows on BAP, CHOC, and MAC
Has biochemical and antigenic similarities to Shigella (obvi)

64
Q

Haemophilus influenzae

A

Normal flora of upper respiratory tract
Mode of transmission is respiratory droplets spread from person to person
Causes sinusitis, otitis media, pneumonia, and bronchitis often in elderly patients
Type B is a common cause of pneumonia and meningitis in children 5 months to 5 years where Hib vaccine is not available
Small, pleomorphic Gram negative coccobacilli to long filaments with capsules
Grows on CHOC with translucent, moist, tannish colonies
Mousy or bleach like odor
Can demonstrate satellitism with staph on BAP

65
Q

H. influenzae biotype aegyptius and H. aegyptius

A

Both cause conjunctivitis (pink eye)
H. influenzae biotype aegyptius also causes Brazilian purpuric fever
Difficult to differentiate from H. influenzae

66
Q

H. parainfluenzae, H. haemolyticus, & H. parahaemolyticus

A

Normal flora of upper respiratory tract
Low incidence of pathogenicity
Small, pleomorphic Gram negative coccobacilli to long filaments
Colonies are larger, dry, and tannish

67
Q

H. ducreyi

A

Never normal flora
Mode of transmission is person to person by sexual contact
Causes chancroid (sexually transmitted disease)
Small Gram negative coccobacilli with bipolar staining
May resemble schools of dish or railroad tracks
Difficult to culture and is identified by PCR
Virulence factors are unknown but it is thought to have a capsule and produce toxins that allow for attachment and penetration in the host cells

68
Q

Bartonella

A

Causes “trench fever”, relapsing fever, bacteremia, endocarditis, and cat-scratch fever
Intracellular Gram negative coccobacilli
Not cultured (takes 9-40 days to grow)

69
Q

Bordetella pertussis

A

Causes whooping cough in children and adults
Small Gram negative coccobacilli
Grows on Bordet-Gengou and Regan-Lowe (charcoal horse blood) after 3-7 days
DTaP vaccine protects against it

70
Q

Brucella

A

Causes brucellosis (undulant fever) from unpasteurized milk or contact with infected goats, cows, hogs, and dogs
Tiny, faintly staining Gram negative coccobacilli
Most often isolated from blood cultures or biopsies of reticuloendothelial tissue
Blood cultures are to be incubated for 3 weeks
Oxidase positive, urease positive
Level 3 pathogen and possible bioterrorism agent

71
Q

Francisella

A

Causes tularemia (rabbit fever)
Infection from bite from infected tick or from handling infected animals
Pale staining, small, pleomorphic, intracellular Gram negative coccobacilli with bipolar staining
Grows on special media that is enriched with glucose and cystine, TM, and BCYE agars
Grows small transparent colonies after three days
Level 3 pathogen that needs to be sent to public health for confirmation

72
Q

Gardnerella

A

Normal flora of female genital tract
Associated with bacterial vaginosis (BV) when it and anaerobic Gram negative rods are predominant and Lactobacillus is absent
Linked to maternal and neonatal infections, bacteremia, and rare UTI
Small, pleomorphic, Gram variable rods
Not recommended for diagnosis of BV
Grows on BAP, PEA, CNA, human blood Tween (HBT)
Produces diffuse beta hemolysis only on media containing human blood
Catalase and oxidase negative

73
Q

Legionella

A

Cause of Legionnaire’s disease (duh) and Pontiac fever
Found in water (air conditioners, showerheads, and whirlpools)
Contracted by inhalation of aerosol
Small, pleomorphic, weakly staining Gram negative rods
Grows on BYCE in 3-4 days and has a pale yellow-green fluorescence with Wood’s lamp
Oxidase positive
Identified by immunofluorescent stain or urine antigen test

74
Q

Pasteurella multocida

A

Contracted by bite or scratch of cat or dog or contact with infected carcass
Causes soft tissue infections, respiratory infections, or bacteremia
Produces an endotoxin and a capsule that contributes to pathogenicity
Pleomorphic Gram negative coccobacilli with bipolar staining
Grows on BAP and CHOC, but not MAC
Also grows well in blood culture media, thioglycolate broth, and BHI broth
Incubate in ambient air or 35-37 degrees C with CO2 for a minimum of 24 hours
Has a musty/mushroom odor
Oxidase, catalase, and indole positive

75
Q

Finegoldia magna

A

Formerly Peptostreptococcus magnus
Normal flora on skin and mouth, intestines, and female genital tract
Most commonly isolated and most pathogenic anaerobic Gram positive cocci
Associated with skin infections, decubitus ulcers, septic arthritis, bone infections following orthopedic surgery, oral infections, female genital tract infections, and bacteremia
Gram positive cocci in singles, pairs, tetrads, and clusters (resembles staph
Can take up to 48 hours to grow
Catalase and indole negative
Resistant to SPS

76
Q

Peptostreptococcus anaerobius

A

Normal on skin and in mouth, GI, and GU tracts
Mixed infections of skin, soft tissues, GI tract, female genital tract, bones, joints, lungs, and brain
Tiny Gram positive cocci in chains (resembles strep)
Sweet odor
Sensitive to SPS

77
Q

Peptoniphilus asaccharolyticus

A

Formerly Peptostreptococcus asaccharolyticus
Normal on skin and in GI/GU tracts
Associated with obstetric and gynecological infections
Gram positive cocci in pairs, short chains, tetrads, and clusters
Yellow colonies
Musty odor
Indole positive
Resistant to SPS

78
Q

Actinomyces

A

Infects the brain, face, lungs, and genitals
Short or long Gram positive rods
Branched or unbranched
Banded appearance
Can break into club shapes resembling diphtheroids
Sulfur granules may be seen in discharge
Crush and stain to reveal characteristic Gram stain morphology
“Molar tooth” colonies

79
Q

Clostridium botulinum

A

Botulism due to ingestion of toxin in inadequately cooked or improperly canned foods
Infant botulism due to ingestion of spores in honey
Wound botulism from injection drug use
Gram positive rod with oval subterminal spores
Reportable disease with toxin testing at public health labs

80
Q

Clostridium difficile

A

Causes antibiotic-associated diarrhea and pseudomembranous colitis
Thin Gram positive rod that may form chains with rare oval subterminal spores
Yellow ground glass colonies on cycloserine cefoxitin fructose agar (CCFA)
Usually not cultured and must demonstrate toxin production for it to be a critical call

81
Q

Clostridium perfringens

A

Normal in GI tract
Causes gas gangrene and food poisoning
Large Gram positive rods with blunt ends in chains resembling “box cars”
Tendency to stain Gram negative
Usually no spores seen
Most commonly isolated Clostridium species
Has a double zone of hemolysis on BAP

82
Q

Clostridium tetani

A

Causes tetanus and deep wound infections from soil
Gram positive rod with swollen terminal spores resembling “drum sticks” or “tennis rackets”
Becomes Gram negative after 24 hours
Rare in the US because of DTaP vaccine

83
Q

Propionibacterium

A

Normal skin flora
Common contaminant of blood cultures
Cause of acne and infections associated with artificial joints, catheters, shunts, artificial heart valves, keratitis, bacteremia, and endocarditis
Club shaped, pleomorphic Gram positive rod
Most common anaerobic Gram positive rods
Catalase and indole positive

84
Q

Lactobacillus

A

Normal in mouth and GI tract
Predominant flora of vagina during reproductive years
Produces lactic acid, maintains vaginal pH
Absence in vagina predisposes to bacterial vaginosis and yeast infections
Rare cause of endocarditis and septicemia in immunocompromised
Pleomorphic, long, thin, non-spore forming Gram positive rods
Aerotolerant anaerobes
Grow better under anaerobic conditions
Colonies vary greatly
May resemble S. viridans
Catalase negative (differentiates from diphtheroids)

85
Q

Veillonella

A

Normal flora of upper respiratory tract and GI/GU tracts
Usually in mixed cultures
Can cause infections in immunocompromised patients
Tiny Gram negative diplococci resembling Neisseria
May show weak red fluorescence under UV light
Doesn’t grow on KVLB
Usually doesn’t reduce nitrates

86
Q

Bacteroides fragilis

A

Cause of mixed infections below the diaphragm
Pleomorphic, pale, irregularly staining Gram negative rods
Most common anaerobe isolated
Resistant to bile
Hydrolyses esculin
Turns BBE brown

87
Q

Fusobacterium

A

Pulmonary infections, brain abscesses, and oral lesions
Gram negative rod
F. nucleatum is long and thin with tapered ends (spindle shaped)
Indole positive
Most fluoresce chartreuse under UV light

88
Q

Porphyromonas

A

Causes head, neck, and pleuropulmonary infections
Gram negative coccobacilli
Slow growing
Brown to black colonies on BAP
Some fluoresce brick-red to orange under UV light
Doesn’t grow on KVLB

89
Q

Prevotella

A

Causes head, neck, and pleuropulmonary infections
Gram negative coccobacilli
Slow growing
Some are pigmented
Brown to black on BAP and KVLB
Some fluoresce brick-red to orange under UV light
Doesn’t grow on BBE

90
Q

Chlamydia trachomatis

A

Most common sexually transmitted bacterial infection in the US
Causes trachoma, lymphogranuloma venereum, nongonococcal urethritis, and pelvic inflammatory disease
Can also cause pneumonia and conjunctivitis in newborns
Obligate intracellular parasite
Epithelial cells are needed for culture (wooded swabs cannot be used because they are toxic)
Can be simultaneously tested with N. gonorrhoeae

91
Q

Chlamydophila (Chlamydia) pneumoniae

A

Third most common cause of acute RTI
Obligate intracellular parasite
Risk factor for Guillain-Barre Syndrome
May also be a risk factor for cardiovascular disease

92
Q

Chlamydophila (Chlamydia) psittaci

A

Causes psittacosis (Parrot fever), very rare in the US
Obligate intracellular parasite spread by birds (duh)

93
Q

Borrelia recurrentis

A

Causes relapsing fever (recurrentis = recurring)
Diagnosed through Giemsa or Wright stained blood smears
Transmitted through ticks and lice

94
Q

Borrelia burgdorferi

A

Causes Lyme disease (erythema chronicum migrans, neurological and cardiac abnormalities, and arthritis)
Grows on modified Kelly medium
Serology testing is most common identification method
Most commonly reported tick-borne infection in the US
Vector is the Ixodes tick

95
Q

Treponema pallidum (subspecies pallidum)

A

Cause of syphilis
Will not grow on artificial media
Diagnosed through darkfield microscopy with fluorescent stain
Worldwide problem

96
Q

Leptospira interrogans

A

Causes Weil’s disease (infectious jaundice, leptospirosis)
Diagnosed through culture (growth = turbidity below surface of semisolid Fletcher’s medium)
Cultures are kept for 6 weeks
Is a zoonotic disease that is transmitted by urine of infected animals
Organism can be found in blood and CSF during first week of infection, then found in the urine

97
Q

Mycoplasma pneumoniae

A

Causes primary atypical pneumonia or “walking pneumonia”
Smallest free living cells
Lack cells walls, pleomorphic, and not visible by Gram stain
Culture is rarely performed because they are so difficult to grow (can take 21 days or more if successful)
Usually diagnosed by serology

98
Q

Mycoplasma hominis

A

Causes urogenital tract disease
Only species that will grow on BAP and CHOC but may require 4 days for growth
Pinpoint translucent colonies easily overlooked
“Fried-egg” colonies can be seen with stereomicroscope after staining with methylene blue

99
Q

Ureaplasma

A

Causes urogenital tract disease
Granular brown appearance on A8 agar because of urease production

M (ASCP) (13 decks)

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