Bateria Intro and Staphylococcus Flashcards by Michael McMahan

Reflects a fundamental differentiation based on permeability, presence or absence of outer membrane and cell wall thickness

Gram stain differentiation

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_______ have more in common with gram positive cocci than with gram negative rods

Gram positive rods

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§ Found in many body sites; primarily skin infections & wounds; carbuncles; abscesses; leading to life threatening deep tissue infections: osteomyelitis, endocarditis
§ Severe intoxications; Food poisoning

Staphylococci

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§ S. aureus; S. saprophyticus; S. epidermidis

Staphylococci

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§Alpha or beta hemolysis 
Alpha: S. pneumoniae
Beta: Groups A-T; 
Group A most prevalent in human disease
§Oxygen-tolerant anaerobes

Streptococci

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________:
•Neisseria meningitidis
•Neisseria gonorrhea

Gram negative cocci

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Gram _____ rods:
•Non-Spore-forming aerobic rods
§Corynebacterium diphtheriae and related diphtheroids
•Spore-forming rods
§Aerobic: Bacillus anthracis (anthrax)
§Anaerobic: Clostridium species, C. botulinum; C. tetani; C. perfringens; C. difficile

Gram positive rods

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•________ gram + rods
§Aerobic: Bacillus anthracis (anthrax)
§Anaerobic: Clostridium species, C. botulinum; C. tetani; C. perfringens; C. difficile

Spore-forming rods

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_______ gram + rods

§Corynebacterium diphtheriae and related diphtheroids

•Non-Spore-forming aerobic rods

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•Enteric bacteria
§Enterobacteriaceae (facultative anaerobes)
-Escherichia coli; Salmonella spp.; Shigella
spp.;Yersinia spp. (pestis; pseudotuberculosis)

ØGram negative rods

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Significant non-enteric \_\_\_\_\_\_ :
§Pseudomonas aeruginosa 
§Haemophilus influenzae
§Bordetella pertussis
§Brucella abortus
§Legionella pneumophila

Gm-rods

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Which type of bacteria gram stain and shape make up enteric bacteria?

Gram neg rods

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_________
üMost common organism in the human intestine.
üCan cause serious disease when deposited into deep tissues. (abscesses)
üCan be also be found in gingival pockets
üVery stinky!

Bacteroides fragilis

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What bacteroides fragilis is what type of bacteria?

Gram Neg rods

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The following are ____ bacteria

•Mycobacterium tuberculosis; M. leprae

Acid-fast bacteria

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The following are \_\_\_\_ bacteria
•Treponema pallidum (syphilis)
•Leptospira spp. (hemorrhagic fever)
•Borrelia recurrentis (relapsing fever)
•Borrelia burgdorferi (Lyme disease)

Spriochetes

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The following are \_\_\_\_ bacteria:
•Chlamydia trachomatis (most common STD)
•Chlamydia pneumoniae
•Rickettsiae (Rocky mountain spotted fever)
•Ehrlichia(arthropod borne) 
•Coxiella burnetti (Q fever)

Strictly intracellular bacteria

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What type of bacteria is staphylococcus?

Gram stain
rod or cocci

Gram + cocci

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Is staphylococcus catalase + or -?

Catalase +

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What is S. aureus aerobic or anaerobic requirements?

Facultative anaerobe

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Reduces the potential of phagocytes to kill: bubbles when tested

catalase

The tissue-invasive potential of staphylococcal infections is directly proportional to coagulase production (S.aureus; notin other Staph. species).
•binds prothrombin: fibrinogen is cleaved anti-phagocytic fibrin coating

coagulase

________: fibrinogen-binding protein:cell surface proteins that bind to foreign materials (like sutures) and to extracellular matrix.

clumping factor

_____: Anti-phagocytic, competes with neutrophils for Fc portion of opsonizing IgGs(on cell surface of S.aureus but not on other staphylococcal strains)

protein A

________ secretion: inhibits phagocytosis by granulocytes by forming pores in phagosomal membranes, and kills phagocytes. Major factor in pus formation.

leukocidin

________ converts plasminogen to plasmin, increasing invasion by digesting fibrin clots and cleaves C3b and IgG to inhibit phagocytosis

staphylokinase

Enzymatic digestion of penicillins(90% strains have plasmid-based antibiotic resistance)

β-lactamase

lyse erythrocytes (lab phenomenon)

hemolysins:

_____ hemolysins: pores) are hemolytic, leukocytic, destroy skin, cause smooth muscle paralysis

α-hemolysins

______ hemolysins: are cytolytic sphingomyelinases that destroy nerves

β-hemolysins

______ hemolysins: lyse like related leukocidin on neutrophil lysosomal membranes

γ-hemolysins

Does complete hemolysis occur with S. aureus?

Yes; B-hemolysis

Does complete hemolysis occur with S. epidermidis?

______: infection of tissue beneath tissue and skin; purulent

Impetigo

______: Collection of pus in a naturally-existing anatomical cavity (e.g. lungs)

Empyema

________ : pus-forming (massive amounts of neutrophils and other leukocytes are lysed by bacterial factors (e.g. leukocidin) and release their lysosomal contents in attempting phagocytic killing of the staphylococci).

pyogenic infections

folliculitis ->furuncles ->carbuncles(systemic) -> bacteremia fever

pyogenic infections

______: overrides the specificity of the T-cell response

Superantigens

Heat-stable (cooking doesnt help!) toxins A, B, C1, C3, D, Eare super-Ag-like: cause of gastrointestinal upset typical of food poisoning

enterotoxins

________ : mass activation of T cells leads to large production of inflammatory cytokines (heat and protease-resistant TSST-1; chromosomal gene)

Toxic Shock Syndrome Toxin TSST

________ (heat-stable, chromosomal), B (heat-labile, plasmid) : SSSS (staphylococcal scalded-skin syndrome)

exfoliative toxin

______: tampon diseaseIncreased oxygenation of vagina by tampons, and foreign surface adhesion, caused massive growth

TSS: Toxic Shock Syndrome

Øexfoliative toxins A, B cause loss of layers of the skin in ______: leads to Neutralizing Ab

SSSS: Staphylococcal Scalded Skin Syndrome

surgery, implant & instrument risk; slime layers and biofilms that can persist and cause issue

Nosocomial Staphylococci

Nosocomial (hospital instruments and implants) infections(often coagulase-negative _________

S.epidermidis

Endocarditis:•acute: 60%_______

S.aureus

Endocarditis:•if artificial heart valves: 80% _______

S.epidermidis

________: dental extraction risk staphylococcus species

S.epidermidis

_____ diseases include: - skin and soft tissue infections - Endocarditis - CNS infections - Pulmonary infections

Staphylococcus diseases

_____ is the most common org responsible for arthritis

Staphylococcus aureus

Coagulase ____ Staphylococcus: Other Staphylococci like S.epidermidis or S.saprophyticus •Thick cell wall, slime capsule, (S.saprophyticus: urease secretion→acute cystitis •Opportunistic hospital pathogens (instruments, catheters, heart valves)

Coagulase negative

_______ (plasmid): >90% penicillin resistantpenicillin-binding protein 2a (chromosomal): causes Methicillin Resistance 50%of hospital strains are MRSA; 20% of community strains are MRSAWhat can you do in case of (Enterococcus-derived) VRSA ? nothing

β-lactamase