Anaerobic bacteriology Flashcards by Iseoluwa Ojo

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

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Obligate anaerobes

-they undergo no ___________
-they can do _____
-are killed by ____
lack certain enzymes such as :
____
_____
____

oxidative phosphorylation

fermentation; oxygen

superoxide dismutase

catalase

peroxidase

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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

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Moderate anaerobes can ________ exposure to air for _______ but cannot _______

Tolerate ; several hours; multiply

multiply

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Strict anaerobes are _____ by only a _______’ exposure to air

killed; few minutes

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Fortunately ____ anaerobes are seldom associated with human infections

strict

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Anaerobes

Bacteria that require anaerobic conditions to _____ and ______

initiate and sustain growth

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Strict (obligate) anaerobe

Unable to grow if there is > than ____% oxygen

0.5

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Moderate anaerobes
Capable of growing between ____% oxygen

2-8

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Microaerophillic bacteria doesn’t grow in air

T/F

It just Grows poorly in air, but better in anaerobic conditions

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Facultative bacteria (facultative anaerobes)

Grows only in the presence of air

T/F

both in presence and absence

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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

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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

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Anaerobes are thought to be the second earliest forms of life

T/F

Earliest

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All life on earth was (aerobic or anaerobic?) for hundreds of millions of years

Anaerobic

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Today anaerobes are found in soil, fresh and salt water, and in ______ of humans and animals

normal flora

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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

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Anaerobes that live outside the body are called “ _________ anaerobes” (Example: ________ species)

Anaerobes that live inside the body are called “ _________ anaerobes”

exogenous ; Clostridium

endogenous

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Most anaerobic infections are from ( endogenous or exogenous ?) sources

endogenous

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Classification of Medically Important Anaerobes

Gram positive cocci
-___________________
Gram negative cocci
–______________

Peptostreptococcus

Veilonella

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Classification of Medically Important Anaerobes

Gram positive bacilli
•__________________________________
•______________
•_____________
•___________
•__________

Clostridium perfringens, tetani, botulinum, difficile

Propionibacterium

Actinomyces; Lactobacillus; Mobiluncus

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Classification of Medically Important Anaerobes

Gram negative bacilli

————-
—————
—————
——————

Bacteroides fragilis, thetaiotaomicron
Fusobacterium
Prevotella
Porphyromonas

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Epidemiology
–Endogenous infections

•Indigenous microflora
Skin: _________, _________

Upper respiratory: __________

Mouth:_____,________

Intestines:_____,_____,________

Vagina: _________

Propionibacterium; Peptostreptococcus

Propionibacterium

Fusobacterium, Actinomyces

Clostridium, Bacteroides, Fusobacterium

Lactobacillus

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Epidemiology
–Endogenous infections

•Profound modification of flora in pathophysiologic states such as:

______________(PPI, antacids)
__________(____)
_________

Antimicrobials and other medications

Surgery (blind loops)

Cancers

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Epidemiology of anaerobes –Endogenous infections Exogenous infections

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

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

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

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

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