Anaerobic bacteriology Flashcards
Concepts in Anaerobic Bacteriology
Normal Air = about ___% O2 and ____% CO2
CO2 Incubator = about _____% O2 and ___%- ___% CO2
Microaerophilic System = ___% CO2
Anaerobic System – __% O2
21; 0.03
15; 5-10
5
0
Obligate anaerobes
-they undergo no ___________
-they can do _____
-are killed by ____
lack certain enzymes such as :
____
_____
____
oxidative phosphorylation
fermentation; oxygen
superoxide dismutase
catalase
peroxidase
Obligate anaerobes grow ONLY in the absence of _______ but vary in their _______ and can be classified as _____ anaerobes or ______ anaerobes
molecular oxygen
sensitivity to oxygen
moderate; strict
Moderate anaerobes can ________ exposure to air for _______ but cannot _______
Tolerate ; several hours; multiply
multiply
Strict anaerobes are _____ by only a _______’ exposure to air
killed; few minutes
Fortunately ____ anaerobes are seldom associated with human infections
strict
Anaerobes
Bacteria that require anaerobic conditions to _____ and ______
initiate and sustain growth
Strict (obligate) anaerobe
Unable to grow if there is > than ____% oxygen
0.5
Moderate anaerobes
Capable of growing between ____% oxygen
2-8
Microaerophillic bacteria doesn’t grow in air
T/F
F
It just Grows poorly in air, but better in anaerobic conditions
Facultative bacteria (facultative anaerobes)
Grows only in the presence of air
T/F
F
both in presence and absence
Anaerobes do not have enzymes for __________________________________, so oxygen can have a _________ or even ________ effect on them
protection against the toxic effects of molecular oxygen
bacteriostatic; bactericidal
Anaerobes require environments with (low or high?) oxidation- reduction potential (redox), so they must live in areas where the redox potential is ( low or high?)
Low
Low
Anaerobes are thought to be the second earliest forms of life
T/F
F
Earliest
All life on earth was (aerobic or anaerobic?) for hundreds of millions of years
Anaerobic
Today anaerobes are found in soil, fresh and salt water, and in ______ of humans and animals
normal flora
Problems in identification of anaerobic infections
1)______ during sampling or transportation leads to no growth
2)identification takes _______ or longer therefore limiting usefulness
3) often derived from ______ , therefor sample contamination can confuse
air in sample
several days
normal flora
Anaerobes that live outside the body are called “ _________ anaerobes” (Example: ________ species)
Anaerobes that live inside the body are called “ _________ anaerobes”
exogenous ; Clostridium
endogenous
Most anaerobic infections are from ( endogenous or exogenous ?) sources
endogenous
Classification of Medically Important Anaerobes
Gram positive cocci
-___________________
Gram negative cocci
–______________
Peptostreptococcus
Veilonella
Classification of Medically Important Anaerobes
Gram positive bacilli
•__________________________________
•______________
•_____________
•___________
•__________
Clostridium perfringens, tetani, botulinum, difficile
Propionibacterium
Actinomyces; Lactobacillus; Mobiluncus
Classification of Medically Important Anaerobes
Gram negative bacilli
————-
—————
—————
——————
Bacteroides fragilis, thetaiotaomicron
Fusobacterium
Prevotella
Porphyromonas
Epidemiology
–Endogenous infections
•Indigenous microflora
Skin: _________, _________
Upper respiratory: __________
Mouth:_____,________
Intestines:_____,_____,________
Vagina: _________
Propionibacterium; Peptostreptococcus
Propionibacterium
Fusobacterium, Actinomyces
Clostridium, Bacteroides, Fusobacterium
Lactobacillus
Epidemiology
–Endogenous infections
•Profound modification of flora in pathophysiologic states such as:
______________(PPI, antacids)
__________(____)
_________
Antimicrobials and other medications
Surgery (blind loops)
Cancers
Epidemiology of anaerobes
–Endogenous infections
Exogenous infections
T
Indigenous microflora of the skin:
Prevalence in areas exposed to air explained by (1) ____________ (2) ______________ of the microhabitats
oxygen consumption by aerobes
low oxidation-reduction potential
Role of Anaerobes
Role in normal host physiology
– Prevent _________ and ______ by ____
– Contributes to _________
colonization & infection by pathogens
host physiology
Role of Anaerobes
Role in normal host physiology
•– Prevent colonization & infection by pathogens
Bacterial interference through _____,_____,_______
Also by Interference with _______
•– Contributes to host physiology
E.g _________ synthesizes ________ and __________________
elaboration of toxic metabolites, low pH, depletion of nutrients
adhesion
B. fragilis; vitamin K ; deconjugates bile acids
Anaerobic Anatomical Sites for Endogenous Anaerobes
anaerobes often cause infection in the urinary tract
T/F
F
Rarely
Anaerobic Anatomical Sites for Endogenous Anaerobes
–GU Tract – cervical and vaginal areas have ____% anaerobes
–GI Tract – Approximately 2/3’s of all bacteria are in the ____; only cultured anaerobically if ___________ is suspected
50
stool
Clostridium difficle
Indications of Anaerobic Infections
Usually _______ ( ____ -producing)
Close proximity to a _____ surface
Infection persists despite _________
purulent; pus
mucosal
antibiotic therapy
Indications of Anaerobic Infections
Presence of ____ odor
Presence of large quantities of _____ (______ or ______ sound when tissue is pushed)
Presence of ____ color or ____ fluorescence
foul
gas; bubbling or cracking
black; brick-red
Indications of Anaerobic Infections
Presence of “ ______ granules”
Distinct morphologic characteristics in ________ preparation
sulfur
gram-stained
Virulence factors
•Lipopolysaccharide - promotes _______, enhanced _________
•Polysaccharide capsule - correlated with _______ production
•Enzymes a. ______ b. ________ which can lead to development of _______ and _____ emboli
abscess formation; coagulation
abscess
Collagenase; Heparinase
thrombophlebitis & septic emboli.
Virulence factors
____ chained fatty acids a. Butyrate- seen in ________ b. succinic acid – reduces _____
Short
dental plaque
phagocytic killing
Virulence factors
•Attachment and adhesion
______ and _______
•Invasion
________ in host tissue (trauma, disease)
________ of the organism
Polysaccharide capsules and pili
Alteration; Aerotolerance
Virulence factors
•Establishment of infection
_________ (B. fragilis)
_________ (Clostridium)
Maintenance of ________ environment
•Tissue damage
___________
Polysaccharide capsule
Spore formation
reduced oxygen
Elaboration of toxins
Clinical features of anaerobic infections
The source of infecting micro-organism is the ____________ of host
________ of host’s tissues provide suitable conditions for development of __________ infections
_______ formation
________ formation
endogenous flora
Alterations; opportunist anaerobic
Abscess; Exotoxin
Anaerobic infections are generally polymicrobial
T/F
T
Specimens for Anaerobic Culture
Tissue – must be placed in _______ transport bag or vial
Blood – ________________________ bottles are collected for most blood culture requests
an oxygen-free
aerobic AND anaerobic
Typical Anaerobic Media
_______________ agar (BRU/BA)
__________________ agar (BBE)
________________________ agar (KVLB)
_____________ agar (PEA)
Anaerobic broth, such as ______,________, or ________ agar
Anaerobic blood
Bacteroides bile esculin
Kanamycin-vancomycin-laked blood
Phenylethyl alcohol
thioglycollate (THIO) , brain heart infusion or chopped meat
Anaerobic Incubation
•Anaerobic ________ (p. 581)
•Anaerobic jars
________________ generate _____ and ____ , which combines with ____
•Anaerobic ______ or _____
chambers
Gas-Pak envelopes
CO2 and H2; O2
bags or pouches
Warning!:
_____ is explosive; _____ catalyst MUST be used with the anaerobic jars
H2; palladium
All anaerobic incubation systems must have ____________ system in place
an oxygen indicator
Definitive Identification of Anaerobes
_______ and ________ biochemical test media
Biochemical-based and preexisting enzyme-based minisystems
______ chromatographic analysis of metabolic end products
_________ analysis by GLC
PRAS (Pre-reduced Anaerobic System) and non-PRAS
Gas-liquid
Cellular fatty acid
Frequently Encountered Anaerobes
Gram-positive spore-forming anaerobic bacilli
– _________
Clostridium
Frequently Encountered Anaerobes
Gram-positive spore-forming anaerobic bacilli
– Clostridium
Most from (endo or exo?) genous sources
Examples:_____,______,_______,______,________
Exo
tetanus, gas gangrene, botulism, food poisoning, pseudomembranous colitis (C. difficle)
Clostridium difficle is most often detected via _______________ detection
direct stool antigen
Frequently Encountered Anaerobes (cont’d)
Gram-positive non-spore-forming anaerobic bacilli
–PALMEB(________________________________)
– Most are from (Endo or Exo?) genous sources and are therefore ______
Actinomyces, Bifidobacterium, Eubacterium, Mobiluncus, Lactobacillus, and Propionibacterium
Endo
opportunists
Frequently Encountered Anaerobes (cont’d)
Anaerobic gram-negative bacilli
– (endo or exo?) genous
– Include _____ group, ______,_____, and ______
Endo
Bacteroides fragilis
Porphyromonas spp., Prevotella spp., and Fusobacterium spp.
Frequently Encountered Anaerobes (cont’d)
Anaerobic cocci
-usually (endo or exo?) genous
-Gram-positive –__________
– Gram-negative – _______ spp.
endo
Peptostreptococcus
Veillonella
Source of spore-formers and non- spore formers
•Spore-formers (______)
– (presence or absence?) of exotoxins
– common in the _______
– also found in ______
•Non - spore-formers
- (presence or absence?) of exotoxins
– mostly _______
clostridia; presence; environment; normal flora
absence; normal flora
Anaerobic cocci
Normal flora of _____,_____,______, and ____
skin, mouth, intestinal and genitourinary tracts
Anaerobic cocci
Pathogenesis
-they are _______ pathogens
-often involved in _______ infections
-can cause Brain ____, ______ disease, _____, skin and soft tissue infections, _______ infections
Opportunistic
polymicrobial
abscesses; periodontal; pneumonias; intra-abdominal
Virulence factors of anaerobic cocci are well characterized
F
not as well characterized
Anaerobic cocci
Peptostreptococcus
P. _____
P. _____
P. _______
magnus
prevotti
anaerobius
Anaerobic cocci
Peptostreptococcus
P. magnus: ____________ infections, especially ______ joints
P. prevotti and P. anaerobius: _________ and ———— infections
chronic bone and joint ; prosthetic
female genital tract and intra- abdominal
Anaerobic cocci
Veillonella
Found in Normal ____ flora
isolated from ________ infections
oral
infected human bites
Anaerobic gram positive bacilli
No Spore Formation
•Propionibacterium
-P.______
•Actinomyces
A. _______
•_______
•_______
Acnes
Israeli
Lactobacillus
Mobiluncus
Anaerobic gram positive bacilli
• SporeFormation
– Clostridium
• C._______
•C. _______
•C. ______
•C. ______
perfringens
difficile
tetani
botulinum
Propionobacterium
-Anaerobic or _____, produces ______ as major byproduct of fermentation
-Colonize ____,_____,______,____,______
aerotolerant; propionic acid
skin, conjunctiva, external ear, oropharynx, female GU tract
P. acnes
•Acne
–Resides in ________ , releases _____ peptide, stimulates _______ response
•Opportunistic infections
–________ devices (_______,———)
sebaceous follicles; LMW; an inflammatory
Prosthetic; heart valves, CSF shunts
Actinomyces
-Could be _____ or ______ anaerobes
-Colonize _____,———-, and _____
-(Low or High?) virulence
-development of disease when ______ are disrupted
Facultative or strict
upper respiratory tract, GI, female GU tract
Low; normal mucosal barriers
Actinomyces
Diagnosis:
-_____scopic colonies of organisms resembling ________(____)
–Culture
Macro
grains of sand (sulfur granules)
Actinomycosis
_________ Actinomycosis
•Can be caused by __________, ___ trauma
• (Rapidly or Slowly?) evolving, (painful or painless?) process
•_________ lesions that become ______ and form ________
Treatment: __________ and ________
Cervicofacial
Poor oral hygiene; oral
Slowly, painless
Chronic granulomatous; suppurative; sinus tracts
surgical debridement and prolonged penicillin
Lactobacillus
-is a ________ or ________ anaerobes
-it Colonizes ____ and _____ tract
-it Produces _____ which is bactericidal to _____________
Facultative or strict
GI and GU
H2O2; Gardnerella vaginalis
Lactobacillus
Clinical disease
Transient _______ from ____ source
Endocarditis
_________ in immunocompromized host
bacteremia; GU
Bacteremia
Vagina heavily colonized (105/ml) by Lactobacillus ______ and ——-
crispatus & jensonii
Mobiluncus
-are ———— anaerobes
-Gram _____ or gram ________
- Colonize ______ in (low or high?) numbers
-Associated with bacterial ______
Obligate
negative; variable
GU tract; low
vaginosis
Mobiluncus is Detected in vagina of ___% of controls and As many as ____% of women with bacterial vaginosis
6
97
Clostridium
Epidemiology
Ubiquitous:
•present in _______
• also present in ________
Pathogenesis
___________ that are resistant to ____,___,______ and can survive for years in adverse environments
Soil, water, sewage
Normal flora in GI Tracts of human and animals
Spore formation; heat, dessication, and disinfectants
Clostridium
Rapid growth in _______, oxygen deprived environment
Toxin elaboration (_______ toxins, ______toxins, ______toxins)
nutritionally enriched
histolytic; entero; neuro
Clostridium perfringens
Epidemiology
•found in ____ of humans and animals
•Type __ responsible for most human infections
GI tract
A
Clostridium perfringens
Pathogenesis
•α-toxin: _____ (phospholipase C) that lyses ______,______, and ______ cells
•ß-toxin:_______ activity
•θ-toxin:________
•Enterotoxin: binds to ______ and disrupts small intestinal transport
lecithinase; erythrocytes,platelets and endothelial
necrotizing; hemolysin
brush borders
Clostridium perfringens
Clinical manifestations
•Self-limited _______
•Soft tissue infections: ______, _______ or ________ (_____ gangrene)
gastroenteritis
cellulitis
fascitis or Myonecrosis
Gas
Clostridial myonecrosis
Clinical course:
-less than _____ hours incubation
-local area marked with ____,———-,_______ discharge, bullae, slight _____
-May be associated with increased _____
48
Pain, swelling , serosanguinous, crepitance
CPK
Clostridial myonecrosis
– Treatment
_________
___________
_______
Surgical debridement
Antibiotics
Hyperbaric oxygen
Clostridium difficile
Epidemiology
•Colonizes _____ of ___% healthy individuals
•Endogenous infection after _____ exposure associated with overgrowth of C. difficile
•Exogenous infection from _____ detected in _______ of infected patients
GI tract; 5
antibiotic; spores; hospital rooms
______ _____ can lead to pseudomembanous colitis
: after _______, the intestinal normal flora is _______ and ______ occurs
Clostridium difficile
antibiotic use
greatly decreased; colonization
C.Difficile pathogenesis
•Enterotoxin (toxin ___)
–produces _____, induces ______ production and ______ of fluid, development of ___________
•Cytotoxin (toxin __)
Induces __________ with loss of cellular _______
A; chemotaxis; cytokine; hypersecretion
hemorrhagic necrosis
B; polymerization of actin ; cytoskeleton
Which exotoxin of Clostridium difficile is more potent
A or B
A
C. difficile
exotoxin A (____,_____)
exotoxin B
- (also a _____)
enterotoxin, cytoxin
cytoxin
C. difficile colitis
Clinical syndromes
•Asymptomatic _______
•Antibiotic-associated ______
•_________ colitis
colonization; diarrhea
Pseudomembranous
C. difficile colitis
Diagnosis
Isolation of the _____ or ______
cytotoxin or enterotoxin
C. difficile colitis
Treatment
• ____________
•________ or ______
•Relapse in __-__% (spores are resistant)
Discontinue antibiotics
Metronidazole or vancomycin
20-30
Clostridium tetani
Epidemiology
•Spores found in _____
•is a Disease in _________ or _____
most soils
un-vaccinated or inadequately immunized
Clostridium tetani infection induces immunity
T/F
F
Disease does not induce immunity
Clostridium tetani
Pathogenesis
•Spores gets inoculated into ____
wound
Clostridium tetani
Tetanospasmin
•Heat-(labile or stable ?) ____toxin
•(Antero or Retro?) grade axonal transport to ___
•Blocks ________________________ resulting in ________ paralysis
Binding is (reversible or irreversible ?)
labile; neuro
Retro; CNS
release of inhibitory neurotransmitters (GABA)
spastic; irreversible
Clostridium tetani
Tetanolysin
•Oxygen (labile or stable ?) __________
Labile
hemolysin
What is the clinical significance of clostridium tetani
unclear clinical significance
Clostridium tetani spore is : sub terminal or terminal?
Terminal
Clostridium Tetanus
Clinical manifestations
•Generalized–
Involvement of _____ and ——— muscles
–______involvement
•Cephalic
–Involvement of _____ nerves only
• Localized
–Involvement of muscles in _____
• Neonatal
–(localized or generalized?) in neonates; infected ________
bulbar and paraspinal
Autonomic
cranial
primary area of injury
Generalized; umbilical stump
Clostridium Tetanus
Treatment
–______ of wound
–_______
– Tetanus ______
– Vaccination with _______
Prevention
– Vaccination with a series of ________
– Booster dose every ___ years
Debridement
Metronidazole
immunoglobulin
tetanus toxoid
3 tetanus toxoid; 10
Clostridium botulinum
Epidemiology
– Commonly isolated in _________
– Human disease associated with __,___,__,__
soil and water
A, B, E, F
Clostridium botulinum
Pathogenesis
– Botulinum toxin targets __________
– Prevents release of _______
– Recovery depends upon ______________
cholinergic nerves
acetylcholine
regeneration of nerve endings
Clostridium botulinum
food poisoning is (common or rare?) ,(fatal or non-fatal?)
germination of spore
Can come from _____________ food
home
Rare
fatal
inadequately sterilized canned
Botulism is an infection
T/F
F
not an infection
Clostridium botulinum
It binds peripheral nerve receptors - acetylcholine neurotransmitter, and inhibits nerve impulses leading to _____ paralysis
•death as a result of
–_______ and ______ failure
flaccid
respiratory and cardiac
Botulinum toxin can be used for ____
resembles a _______
Bioterrorism
Chemical attack
Botulism
Clinical Syndromes
______ botulism
______ botulism
______ botulism
Food borne
Wound
Infant
Clinical Syndromes of botulism
Foodborne botulism
•Mostly associated with _____ foods and preformed ____
•Onset of symptoms _____ days
•_____ vision, ______ pupils, ____ mouth, constipation
•Bilateral (ascending or descending?) weakness of _______ muscles
•death related to ______ failure
home-canned ; toxin
1-2; blurred; dilated; dry
Descending; peripheral
respiratory failure
Clinical syndromes of botulism
Infant botulism
•Consumption of foods contaminated with ______
•Disease associated with ____toxin produced in ____
botulinum spores
neuro; vivo
Bacteroides fragilis
(major or minor?) component of gut flora
Minor
most common (strict) anaerobic infection after abdominal surgery is ????
Bacteriodes fragilis
Anaerobic gram negative bacilli
Epidemiology
– Colonize human body in (minute or great?) numbers
- they ______ resident bacterial flora
- they Prevent ______ by pathogens
Great; Stabilize; colonization
(Aerobes or Anaerobes?) are predominant bacteria in upper respiratory tract, GI and GU tract
They Outnumber the other type of bacterias by _________ fold
(Little or Many?) species, (many or few?) pathogens
Anaerobes
Aerobes
10-100
Many; few
Bacteroides
Epidemiology
It is associated with ____% of intra-abd infx
80
Pathogenesis of Bacteriodes fragilis
•________ capsule
•________ and ______
•Elaborate a variety of enzymes
Polysaccharide
Superoxide dismutase and catalase
Pathogenesis of Bacteriodes
•Polysaccharide capsule
–Increases _______ to peritoneal surfaces (along with fimbriae)
-Protection against ________
adhesion; phagocytosis
Polysaccharide capsule of anaerobic GNR Differs from LPS of aerobic GNB
T/F
How?
T
Less fatty acids linked to Lipid A component
Less pyrogenic activity
Bacteroides fragilis
Major disease causing strict anaerobic non-spore-former
T/F
T
Note the strict
Bacteriodes fragilis
(Endo or Exo?) toxin
(low or high?) toxicity
structure (the same or different ?) than other lipolysaccharide
Endo
Low
Different
Bacteriodes fragilis
Presence of beta lactamase
T/F
T
Bacteroides
Infections
–_________ infections (peritonitis, ______); _______; decubitus and ____ ulcers
Treatment
–______ of abscess and ______ of necrotic tissue
– ________
Intra-abdominal; abscess
bacteremias; diabetic
Drainage; debridement
Antibiotics
Specimens for Anaerobic Culture
Aspirates
– Should be collected with _________
– Specimen injected into _______ transport ______ or ____
Swabs
– if collected, must be transported in
_________ system
needle and syringe
oxygen-free ; tube or vial
An anaerobic
Collection, Transport and Processing Specimens for Anaerobic Culture
Any specimen collected on a swab is usually not acceptable because _____________________
of the possibility of having normal anaerobic organisms
Compare bacterial growth of obligate aerobe, Microaerophilic, facultative anaerobe, and obligate anaerobe
Aerobe- at the top top surface
Micro- below the surface but still top
Facultative- the entire thing
Anaerobe- the bottom
What disease can u find
Risus sardonicus
Tetanus
Risus sardonicus
Aka
Evil grin
Second symptom of tetanus?
First is Risus sardonicus
Second is opisthotonos
Colitis caused by C.difficile must not be given IV vancomycin
T or F
T
Must be given oral vancomycin because we want the slow absorption
The presence of sulphur granules suggest what bacteria
Actinomycetes
