Bateria Intro and Staphylococcus Flashcards
Reflects a fundamental differentiation based on permeability, presence or absence of outer membrane and cell wall thickness
Gram stain differentiation
_______ have more in common with gram positive cocci than with gram negative rods
Gram positive rods
§ 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
§ S. aureus; S. saprophyticus; S. epidermidis
Staphylococci
§Alpha or beta hemolysis Alpha: S. pneumoniae Beta: Groups A-T; Group A most prevalent in human disease §Oxygen-tolerant anaerobes
Streptococci
________:
•Neisseria meningitidis
•Neisseria gonorrhea
Gram negative cocci
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
•________ gram + rods
§Aerobic: Bacillus anthracis (anthrax)
§Anaerobic: Clostridium species, C. botulinum; C. tetani; C. perfringens; C. difficile
Spore-forming rods
_______ gram + rods
§Corynebacterium diphtheriae and related diphtheroids
•Non-Spore-forming aerobic rods
•Enteric bacteria
§Enterobacteriaceae (facultative anaerobes)
-Escherichia coli; Salmonella spp.; Shigella
spp.;Yersinia spp. (pestis; pseudotuberculosis)
ØGram negative rods
Significant non-enteric \_\_\_\_\_\_ : §Pseudomonas aeruginosa §Haemophilus influenzae §Bordetella pertussis §Brucella abortus §Legionella pneumophila
Gm-rods
Which type of bacteria gram stain and shape make up enteric bacteria?
Gram neg rods
_________
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
What bacteroides fragilis is what type of bacteria?
Gram Neg rods
The following are ____ bacteria
•Mycobacterium tuberculosis; M. leprae
Acid-fast bacteria
The following are \_\_\_\_ bacteria •Treponema pallidum (syphilis) •Leptospira spp. (hemorrhagic fever) •Borrelia recurrentis (relapsing fever) •Borrelia burgdorferi (Lyme disease)
Spriochetes
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
What type of bacteria is staphylococcus?
- Gram stain
- rod or cocci
Gram + cocci
Is staphylococcus catalase + or -?
Catalase +
What is S. aureus aerobic or anaerobic requirements?
Facultative anaerobe
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?
No
______: 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
