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Bacteriology OSU
Bacteriology exam 3 and 4
Question | Answer |
---|---|
Penicillin (beta lactam) | Blocks cross-linking of pentaglycyl bridge; leads to weakened mucopeptide and cellular lysis, spheroblast protoplast cytolysis; more effective in gram +, Requires growing cells; do not use with bacteriostatic drugs; |
How to resist penicilins | penicillinase, beta-lactamase hydrolyze beta-lactam ring to acid to inactivate most common and semisynthetic beta-lactams; constitutive or inducible altered penicillin-binding proteins; efflux |
Cephalosporin (beta lactam) | Binding enzymes involved in final process of cell wall synthesis inhibiting polymerization and attachment of new peptidoglycan to cell wall |
Resist cephalosporin by | Cephalosporinase, beta-lactamase hydrolyze beta-lactam ring to acid to inactivate most common and semisynthetic beta-lactams; constitutive or inducible; altered penicillin-binding proteins; efflux |
Vancomycin (glycopeptide) | Blocks crosslinking of peptidoglycan pentapeptides Vancomycin resistance |
Polymyxin | Affects cell membrane permeability; passes thru outer membrane of gram neg, dissolves cytoplasmic membrane; confined to gram neg No longer permeable or recognized |
Aminoglycosides (protein synthesis inhibitor) | Bind to 30S ribosome subunit to give misreading leading to missense or nonsense proteins |
Aminoglycoside resistance | Modification of antibiotic by acylation, phosphorylation, or adenylation |
Tetracyline (protein synthesis inhibitor) | Bind to 30S, blocks tRNA access prevent translation; bacteriostatic; Normally appears increments, carried on R-factors, decreased transport; |
Tetracyline resistance | efflux; ribosomal protection |
Macrolides (protein synthesis inhibitor) | (erythromycin) Prevent transpeptidation; bound to 50Sblocking macromolecule synthesis; gram pos Resist tetracyline by |
Chloroamphenicol (protein synthesis inhibitor) | Binds to 50S to prevent translation by blocking protein bond formation, also effects mammalian ribosomes; gram pos and neg; nonspecific |
Chloramphenicol resistance | Modification of acylation |
Lincosamide (protein synthesis inhibitor) | Blocks binding of 50S; erythromycin reverses effects; effective against anaerobes |
Lincosamide resistance | Modified and removed |
Aminocylitol (protein synthesis inhibitor) (spectinomycin) | Binds 30S; gonorrhea; chemotherapy; treats PPNG, Syphilis; modified and removed |
Sulfa Drugs (antimetabolite) | Bacteriostatic; competitive antagonism of para-aminobenzoic acid which leads to folic acid |
Sulfa Drugs resistance | Ineffective in presence of lysed cells in wound and also suppuration-- synthesis of enzymes insensitive to the axn of the drug |
Quinolone | (inhibitor of DNA/RNA synthesis) (Cipro) Block DNA gyrase which is essential for DNA replication and repair; pentrates most tissue Mutational alternation of target (GyrA, TopoIV, Par);resist by efflux |
Staphylococcus aureus | gram Pos; causes Boils, skin sepsis; postoperative wound infection; scalded skin syndrome; catheter associated infection; foodborne infection; septicemia, endocarditis; toxic shock syndrome; osteomyelitis; pneumonia |
Staphylococcus aureus virulence factors | Mucopeptide- toxic, antiphagocytic;Coagulase,diagnostic Cell Associated- capsul, protein A, fibronectin-binding protein, collagen-binding proteins, only species with protein A |
Staphylococcus epidermis | gram Pos;Device related sepsis such as:Catheter-related sepsis; prosthetic valve endocarditis; infection of artificial joints; shunt infections UTI; sternal wound osteomyelitis, MRSE common |
Virulence factors of Staphylococcus epidermis | Extracellular slime (makes biofilm) production may be a marker of virulence and aid in colonization of plastic implants. |
Virulence factors of Staphylococcus epidermis | Extracellular slime (makes biofilm) production may be a marker of virulence and aid in colonization of plastic implants. |
Staphylococcus saprophyticus | gram Pos; UTI in previously healthy women (associated with intercourse);Unknown; Can colonize periurethral skin and mucosa |
Streptococcus pyogenes | gram Pos;Upper respiratory infections and of skin and soft tissue (pharyngitis, cellulitis, “flesh eating”, erysipelas, lymphadenitis).Scarlet Fever; Non-Supportive Sequela: Acute Glomerulonephritis and Rheumatic Fever. |
Toxic Shock Syndrome | Erythrogenic toxin, streptolysins, streptokinase A and B, deoxyribonuclease; hyaluronidase (spreading factor), M and T antigen |
Streptococcus agalactia | gram Pos;Neonatal meningitis and septicemia;Mastitis in bovines Not known; Fulminating sepsis;CNS involvement |
Streptococcus mutans | Pos; Dental Caries Capable of causing endocarditis |
Enterococcus (fecal strep) | Pos;UTI; endocarditis; infrequent, but severe septicemia after surgery in immunocompromised.Plasmid-mediated hemolysin may play a role. |
Streptococcus pneumoniae | Pos;Pneumonia Septicemia, Meningitis, Otitis in children, Leading cause of otitis media; virulence factor Capsular type 3 associated with pneumonia. |
Capsule protects from phagocytosis.Pneumolysin may play a role as a virulence factor but to date no known exotoxins; Viral infxn may be a precursor to pneumonia. | |
Virulence of Streptococcus pneumoniae | Capsule protects from phagocytosis.Pneumolysin may play a role as a virulence factor but to date no known exotoxins; Viral infxn may be a precursor to pneumonia. |
Bacillus anthracis | Aerobic Spore-Former; Pos; Anthrax; Woolsorter’s disease (inhalation anthrax);Polyglutamic acid capsule is antiphagocytic. |
Exotoxin encoded on a temperature sensitive plasmid is produced; Toxin has 3 components: | |
Anthracis virulence factors | Exotoxin encoded on a temperature sensitive plasmid is produced; Toxin has 3 components: |
1) Edema factor 2) Lethal Factor 3)Protective Antigen. | |
Toxin acts locally on skin and lung. Individually the components have no biological effect but toxicity is produced by either of the 1st two factors together with the Ag. | |
Bacillus cereus | Pos;Food poisoning (rice and pulses);Rare- bacteremia (especially in immunocompromised);Some strains produce heat stable toxin in food associated with spore germination.Vomiting w/I 1-5 hours;Others produce a leat liable enterotoxin after ingestion.Diarrh |
Clostridium botulinum | Anaerobic Spore-Formers;Pos;Intoxication is associated with disturbances of PNS function.Toxin specifically acts at the myoneural junction to produce complete paralysis of cholinergic nerve fibers; death |
Patient may have diplopia or dysphagia Incubation period is 8-36 hours. | Because of Clostridium Botulinum infection |
Botulinum | Inactivated by heating 100 degrees C for 10 minutes of 85 degrees C for 30 minutes. Polyvalent antitoxin is available. |
Clostridium tetani | Pos; Respiratory complications may occur;Site of action is the synaptosome although MODE of action is unclear.Toxin binds to gangliosides in synaptic membrane;Dependent on number and position of sialic acid residue in ganglioside;Excitation of CNS blockin |
Corynebacterium diphtheriae | Pos;Non-toxigenic organism can colonize so factors other than toxin production determines the disease. Invasiveness is controlled by a bacterial gene; toxin production is controlled by a phage gene (tox gene) Capsular antigens;Long chain fatty acids;Neura |
Breaks down mucous for energy | |
Classic A-B exotoxin which catalyzes ADP-ribosylation of EF-2 | |
diptheriea toxins | Classic A-B exotoxin which catalyzes ADP-ribosylation of EF-2 |
Lysogeny and Tox gene;One tox molecule can inactivate an entire EF-2 content of a cell | Pos;Acne and cutaneous lesions |
Corynebacterium acnes | Pos;Acne and cutaneous lesions |
Corynebacterium parvum | Pos |
Corynebacterium minutissimum | Pos |
Group JK | Pos |
Listeria monocytogenes | Pos;Primarily zoonoses.Neonatal sepsis or meningitis;Granulomatosis infant septicemia, can cross placenta (VERY rare for bacteria); Can cross BBB;Cold enrichment.O and H antigens;Several serogroups with one or multiple serovars. |
Erysipelothrix | Pos;Occupational disease in humans |
Neisseria meningitides | Neg;Metastatic lesions, petechiae, purpura hemorrhage. |
Neisseria meningitides | Meningococcemia which may progress rapidly to septic shock and meningitis.Waterhouse- Friderichsen syndrome- collapse of adrenals Capsular polysaccharide, lipopolyoligosaccharide (LOS), lipid A plus core w/o O antigen side chain |
Virulence factors of Neisseria menigitides | Immunoglobulin degrading enzymes, IgA proteases;Pili- allows adherence.Disseminated by direct contact and droplet infection |
Neisseria meningitides virulence factors | Immunoglobulin degrading enzymes, IgA proteases;Pili- allows adherence.Disseminated by direct contact and droplet infection |