Gram Positiv Bacilli Flashcards
6 medically important genera of GPB:
List them
Bacillus
Clostridium
Corynebacterium
Listeria
Gardnerella
Erysipelothris
Out of the 5 medically important genera of GPB, which have spores and which do not
Bacillus and Clostridium – spores
Corynebacterium, Listeria, and Gardnerella –no spores
Based on their tolerance for oxygen
Bacillus – ______
Clostridium - ______
Corynebacterium -_____
Listeria – _______
Gardnerella – ______
aerobic
anaerobic
aerobic
falcultative anaerobe
falcultative anaerobe
Gram staining appearance
These GPB can also be distinguished based on their appearance
________ and ________ are longer and more deeply staining than _________ and ________
Bacillus and Clostridium spp
Corynebacterium and Listeria spp
Corynebacterium species are _____-shaped
Corynebacterium and Listeria species
characteristically appear as ____ or ___ shaped rods
club
Gardnerella vaginalis is a (short or long?) and gram ______
Short
variable
General Characteristics of Bacillus
~___ species
Gram- _____or Gram- _____ bacilli
(Small or Large?) (0.5 x 1.2 to 2.5 x 10 um)
60
positive; variable
Large
General Characteristics of Bacillus
Most are __________ or _________
Bacillus _________ is most important member
saprophytic contaminants or normal flora
anthracis
General Characteristics of Bacillus
Presence or absence of endospores?
Catalase (positive or negative?) (most)
Presence
Positive
General Characteristics of Bacillus
Bacillus spp. are ubiquitous
T/F
T
Soil, water, and airborne dust
General Characteristics of Bacillus
Thermophilic (< 75°C) and psychrophilic (>5-8°C)
Can flourish at _________ PH (pH _____)
extremes of acidity & alkalinity
2 to 10
Bacillus Endospores
(Thin or Thick?) walled structures formed by _______ cells
Thick ; vegetative
Bacillus endospores
Are Resistant to radiation, chemicals, heat, desiccation (dipicolinic acid)
T/F
T
__________ is necessary for destruction of bacillus endospores
Steam autoclaving
List 5 species of bacillus
Anthracis
Cereus
Mycoides
Thuringiensis
Others🌚
Laboratory Characteristics of Bacillus
On blood agar
(Small or Large?) , spreading
_______ colored colonies with ( regular or irregular?) margins
Large
gray-white
Irregular
Laboratory Characteristics of Bacillus
On blood agar
Many are (alpha or beta?) -hemolytic which is helpful in _____________
Beta
differentiating various Bacillus species from B. anthracis
Laboratory Characteristics of Bacillus
On blood agar
Spores seen after ____ days of incubation, but not typically in _________ specimens
several
fresh clinical
Virulence of B. Anthracis
Virulent strains produce ______ exotoxins that combine to form _____ toxin and ____ toxin
three
edema
lethal
edema toxin = _____ + _____
lethal toxin = ____ + ______
protective antigen; edema factor
protective antigen; lethal factor
Epidemiology of B.anthracis
Primarily infects _____ with _____ as accidental host
Rarely isolated in ______ countries but is prevalent in ______ areas where __________
herbivores
humans
Developed
Impoverished
vaccination of animals is not practiced
Epidemiology of B.anthracis
People at risk are those in endemic areas in _________________, and people who _____________
contact with infected animals or contaminated soil
work with animals imported from endemic areas
There is little concern that the spores of bacillus Anthracis would be used for bioterrorism
T/F
F
Significant concern
Diseases of Bacillus Anthracis
___________ is the most common form
___________ is the most deadly form
________ is a rare form but commonly fatal
Cutaneous anthrax
Inhalational anthrax
Gastrointestinal anthrax
Treatment of bacillus Anthracis
_______ is the drug of choice
It’s resistant to ______
Ciprofloxacin
Sulfonamides and extended spectrum cephalosporins
Prevention of bacillus Anthracis
_________ can control disease but the spores are difficult to eliminate from _____
Vaccination of animal herds
Soils
In Prevention of bacillus Anthracis
______ vaccination is effective
_______ vaccination has limited usefulness
Animal
Human
Bacillus cereus Group
Gastroenteritis
Can grow in food and cause food poisoning by either producing:
Heat-stable enterotoxin (_____form)
Heat-labile enterotoxin (______ form)
emetic
diarrheal
Bacillus cereus Group
Gastroenteritis
Heat-labile enterotoxin (diarrheal form)
Similar to ______ – stimulates cAMP which leads to _______
V. cholera
watery diarrhea
Bacillus cereus Group
Other Clinical conditions
_______ infections after trauma
_______-related sepsis, _____,_____
Ocular
IV-catheter
endocarditis, meningitis
Bacillus cereus Group
Other Clinical conditions
Ocular infections after trauma
–______ toxin, _______, phospholipase C
IV-catheter-related sepsis, endocarditis, meningitis
–_________ persons and _____
Necrotic ; hemolysin
Immunocompromised
drug abusers
L. monocytogenes
Widespread in nature.
Causes _________.
listeriosis
L. monocytogenes
Very (Common or Rare?)
______ cases, ____ deaths
_____% fatality.
Rare
2,500; 500
2- 30
Listeria monocytogenes
•Gram- _____bacilli/______
•Catalase- ________
•Motile or Non-motile ?
positive ; coccobacilli
positive
Motile
Listeria monocytogenes
•Esculin positive or negative?
•___ hemolytic
•Multiplies at __ o C
Positive
beta
4
LISTERIOSIS
(Symptomatic or Asymptomatic?)
(mild or sever?) GI, unless disseminated infection (________) which leads to ______
Asymptomatic
mild
Bacteremia; Meningitis
LISTEROSIS
Requires _________ to clear.
______CELLULAR PATHOGEN.
cellular immune response
INTRA
At-risk populations for invasive listeriosis
_______ women/ _____
Patients at _______
Patients with _____
Pregnant; fetuses
extremes of age
AIDS
At-risk populations for invasive listeriosis
Patients taking _________ medications
Patients with immunosuppressing co-morbidities (cancer, autoimmune disease, alcoholism, diabetes mellitus)
immunosuppressive
Listeria: Pathogenesis
Organism adapted to grow at (low or high?) temperatures
Multiplies in _______ of ———- and ———
Low
cytoplasm of macrophages and epithelial cells
Listeria toxin
_______ O which is a _______
Asymptomatic carriage reservoir
Listeriolysin
hemolysin
Corynebacterium
Gram- ____
Are curved pleomorphic rods “ _______ ”
positive
Chinese Letters
Corynebacterium
Grow readily on _____ agar
Catalase & oxidase ______
Usually (motile or non-motile?)
Sheep blood
positive
Non-motile
Corynebacterium
Are Commensals on ____
Some species pathogenic
skin
Two Lethal Pathologies of corynebacterium
______
_______ due to ______
Suffocation
Organ damage; Diphtheria Toxin (DT)
Two Lethal Pathologies of corynebacterium
Suffocation - edema (i.e., “_______ ”) + ___________
Organ damage due to Diphtheria
Toxin (DT). Usually, the ____ (i.e., severe _______ ).
bull neck; pseudomembrane closes airways.
heart; myocarditis
Diphtheria (C. diphtheriae)
Spreads by ______
_________ increases vascular permeability & promotes spread
droplet
Phospholipase D
Diphtheria (C. diphtheriae)
____-coded exotoxin (_____ subunits) acts on _____ mucous membranes interfering with protein synthesis by inactivating ____
Phage; A&B; respiratory; EF-2
Diphtheria (C. diphtheriae)
_________ of _____,___,_____,______ impairs breathing
Pseudomembrane of fibrin, bacteria, epithelial & phagocytic cells
Diphtheria (C. diphtheriae)
Toxin spreads to _____,_____, and ______
heart, CNS, & adrenals
Diphtheria (C. diphtheriae)
Selective media (______-_____ ) Identify in Public Health Labs
Protect by _____ vaccination - _____
< ___ cases/yr in US
cysteine-tellurite
toxoid; DaPT
5
Diphtheria usually presents as _______ or _____
pharyngitis or tonsillitis
Other Pathogenic Corynebacteria
C. __________
C. __________
jeikeium (JK)
urealyticum
Other Pathogenic Corynebacteria
C. jeikeium (JK)
Opportunistic bloodstream infections in ________________ recipients
Multiple antibiotic resistance - except _______ and ______
Commonly carried on ______ of ________ persons
bone marrow transplant
vancomycin and tetracycline
skin of hospitalized
Other Pathogenic Corynebacteria
C. urealyticum
Occasional cause of ——— and ——— (______)
UTI & stones
splits urea
Corynebacterium diphtheria sometimes presents as skin lesions
T/F
T
Spore positioning and species
_________ spore C. tetani
________ spore C. perfringens
__________ spore C. septicum, novyi, histolyticum difficile, botulinum
Terminal
Central
Subterminal
Wounds and soft tissue infection
________________ is the most common invasive clostridial species (but other species can cause similar effects – C. novyi, C. septicum)
The organism requires_____ tissue with ____ conditions, _____ blood supply, complex nutrients, and ______ ions
C. perfringens type A
damaged; anaerobic; impaired
Ca++
Wounds and soft tissue infection
C. perfringens type A
Produces ___ toxins that attack membranes, including:
– alpha -toxin (_____, AKA “_____”)
–_______________ (hydrolyzes phosphatidylcholine and sphingomyelin-kills cells)
12
lecithinase; myotoxin
zinc metallophospholipase
Wounds and soft tissue infection
C. perfringens type A
Toxins destroy ______, produce ______
Organisms produce ____ when they grow = _______ in tissue
PMNs; myonecrosis
gas; crepitance
Anaerobic growth
Anaerobes will grow at the ____ of tubes of static nutrient broth
bottom
To separate facultative from obligate anaerobes you must plate out the growth from the _____ of the tubes
bottom
Most obligate anaerobes produce a distinctly ———— odor!!
unpleasant
Clostridial diseases in which culture is not usually done
Mention 4
Food poisoning
Tetanus
Botulism
Antibiotic-associated colitis
C. perfringens food poisoning
Improperly-handled food is contaminated with spores, which survive ________
Spores germinate with heating ( ________ ) and if > ____/g bacteria are ingested, illness may occur
cooking temperature
anaerobiasis
10^5
C. perfringens food poisoning
_______ in the small intestine releases ______
Diarrhea (with or without?) fever occurs 6-18 hours later, and resolves in 1-2 days
Sporulation
enterotoxin
Without
Generalizations about invasive Clostridium spp.
________ is critical for survival in the environment (soil)
Disease is mediated by _____-release from _______ cells
Sporulation
exotoxin; vegetative
Generalizations about invasive Clostridium spp.
Exogenous infections = spores in ________
Endogenous infections = vegetative bacteria released from ________
wounds
colonized sites (e.g., colon)
Generalizations about invasive Clostridium spp.
Treatment: ————- are effective, but not in ______ tissues; _______ is often required
Simple antibiotics
non- viable
surgery
Generally, In invasive clostridium spp, Antibiotic resistance is a problem
T/F
F
Antibiotic resistance is not a problem
Clostridium
Alpha-toxin is a _____ that destroy cell membranes, including _____ and _____
lecithinase
PMNs and muscle cells.
Clostridium
C. septicum bacteremia may signal ______
colon cancer
Clostridial enterotoxin causes a __________________(_________) but is not ______ most cases.
self-limited diarrhea (food poisoning)
invasive
Gardnerella _____ is the only species of Gardnerella
T/F
vaginalis
T
Gardnerella
The organisms are (small or large?) (1.0–1.5 μm in diameter)
spore or non-spore-forming?
motile or nonmotile coccobacilli?
Small
Non -spore
Non motile
Gardnerella
G.vaginalis - ____- hemolytic on media containing _____ or _____ blood but not on _____ blood agar
beta
human or rabbit
sheep
Bacillus is versatile in degrading complex macromolecules
T/F
T
Bacillus
Motile or Non Motile
Non Motile
bacillus can be used as a source of antibiotics
T/F
T
Virulence factors of Bacillus Anthracis
_____
________
———
_____
Capsule
Spores
Anthrax toxins
Plasmids
Virulence factors of Bacillus Anthracis
Spores: resistant to ________ , withstand _______ and certain ____ for moderate periods, and persist for years in dry earth.
environmental changes
dry heat
chemical disinfectants
Virulence factors of Bacillus Anthracis
Anthrax toxins are made up of three proteins, _______,_____, and ________
protective antigen (PA), edema factor (EF), and lethal factor (LF).
In bacillus Anthracis, the same plasmid encode genes for toxin and capsule production
T/F
F
different plasmids encode genes for toxin and capsule production
3 major types of anthrax
Cutaneous( approximately ____% of cases)
Inhalation anthrax /____ disease(___%)
Gastrointestinal anthrax -very (common or rare?) ;
95
woolsorters;5
Rare
Culture of bacillus Anthracis :
• on ___ agar plates
•the organisms produce ___hemolytic gray to white, tenacious colonies with a rough texture and a ground-glass appearance.
•_____-shaped outgrowths (_____, “_____”) may project from the colony.
blood
non
Comma; Medusa head; curled hair
Capsule demonstration of Bacillus Anthracis requires growth on ______-containing medium in 5–7% carbon dioxide
bicarbonate
Definitive identification of Bacillus Anthracis
requires lysis by a specific _____________
detection of the capsule by _______, or identification of toxin genes by _________.
Serology: ELISA
anthrax γ-bacteriophage
fluorescent antibody
polymerase chain reaction (PCR)
Control measures against bacillus Anthracis include
(1) disposal of ____ by ______ or by _____
(2) decontamination (usually by _____) of animal products
(3) _______ and ______ for handling potentially infected materials, and
(4)_______ of domestic animals and high risk individuals with _________
animal carcasses; burning; deep burial in lime pits
autoclaving
protective clothing and gloves
active immunization; live attenuated vaccines
Both Bacillus _______ and Bacillus _______ may occasionally produce disease in immunocompromised humans
cereus
thuringiensis
C botulinum
The spores are highly heat resistant can withstand _____°C for _______
Heat resistance is diminished at ____ pH or _______ concentration
100; several hours
acid; high salt
C botulinum
Toxin is liberated into the environment during the _____ of C botulinum and during ______ of the bacteria
___ antigenic varieties of toxin (__-__) are known
growth; autolysis
7; A-G
C botulinum toxins
The lethal dose for a human is probably about __-___μg/kg.
The toxins are destroyed by ____ for ____ at _______.
1–2
heating
20 minutes
100°C
C botulinum toxins are among the most toxic substances known
T/F
T
Botulinum toxin is considered to be a major agent for bioterrorism and biologic warfare
T/F
T
Clinical findings of C. Botulinum
•Symptoms begin __-___ after ingestion of the toxic food, with _____ disturbances (incoordination of _____, double vision),
inability to ____, and _____ difficulty
•signs of ____ paralysis are progressive
•Death occurs from _______ or ______
•(little or no?) fever and patient remains( not , semi, or fully?) conscious until shortly before death.
18–24 hours; visual; eye muscles
swallow; speech; bulbar
respiratory paralysis or cardiac arrest.
No ; fully conscious
Survivors of botulism develop antitoxin in the blood and the mortality rate is (low or high?)
T/F
F
do not develop antitoxin in the blood and the mortality rate is high
Treatment of botulism : ——— and _____
Prevention and control: _____ and _____
antitoxin and supportive care
Food hygiene ; Preheating of canned food
C tetani causes tetanus
produce the toxin ______ and ______
tetanospasmin and tetanolysin
Corynebacterium
contain ______ granules that give the ———- appearance
metachromatic
rod a beaded
Individual corynebacteria in stained smears tend to lie _______ or _____________ (Chinese lettering appearance)
parallel or at acute angles to one another
L monocytogenes
has a tumbling _______ motility at _____°C but not at ___°C
End-over-end
22–28
37
ERYSIPELOTHRIX RHUSIOPATHIAE
Causes ______ (usually occurs on the _____ by direct inoculation at the site of a cut or abrasion)
erysipeloid
fingers
ERYSIPELOTHRIX RHUSIOPATHIAE
there may also be _____ form and _____ with _____
diffuse cutaneous
bacteremia with endocarditis.
E rhusiopathiae is unique among gram-positive rods in that it _______________
produces H2S on TSI slant
Actinomycetes
Causes _____
form _____ chains with occasional ______
Are acid fast because of ________
actinonycosis
elongated; branches
the presence of mycolic acid
Actinomycetes
_____,_______ and a few others of clinical significance.
Nocardia, Rhodococcus,
________ and _______, two agents that cause actinomycotic mycetomas, are acid-fast stain (positive or negative?) .
Streptomyces and Actinomadura
Negative
Nocardia species are _____, beaded gram-positive rods found in soil and other environmental sources
branching
Nocardia species
cause _____ disease ( ______ )primarily in immunocompromised patients.
systemic
norcadiosis
