Bacteriology Flashcards
Catalase positive
Coagulase negative
Staph epidermidis
Staph saprophyticus
Catalase positive
Coagulase negative
Novobiocin sensitive? Resistant?
Sensitive: S. epidermidis
Resistant: S. saprophyticus
Gram+ bacilli
B cereus! No Diet, haLa TATABA Eu! B. cereus Nocardia Diptheria Listeria Tetanus Anthrax TB Actinomyces Bifidobacterium Acnes (Propionibacterium) Eubacterium
Grape-like clusters with golden colonies on blood agar is salt-tolerant on which agar
Mannitol salt agar
Gold colony color of S aureus is due to what pigment
Staphyloxanthin
S aureus habitat
Anterior nares and skin
Immunomodulator: prevents complement activation
Protein A
Immunomodulator: builds an insoluble fibrin capsule
Coagulase
Immunomodulator: Hemolysin is toxic to which type of cells
Hematopoietic cells
Immunomodulator: this is specific for white blood cells found in S aureus
PV Leukocidin (Pantonvalentine)
Immunomodulator: detoxifies hydrogen peroxide
Catalase
Immunomodulator: inactivates penicillin derivatives
Penicillinase
Catalase positive
Coagulase positive
Staph aureus
Virulence factor for tissue penetrance in S. aureus which hydrolyzes hyaluronic acid
Hyaluronidase
Virulence factor for tissue penetrance in S. aureus which dissolves fibrin clots
Fibrinolysin (Staphylokinase)
S. aureus toxins which causes epidermal separation
Exfoliatin
Superantigens causing food poisoning
Enterotoxin (heat-stable)
Superantigen leading to toxic shock syndrome
Toxic shock syndrome toxin (TSST-1)
S. aureus virulence factor which causes marked necrosis of the skin and hemolysis
Alpha toxin
Sequestered focus of osteomyelitis arising in the metaphyseal area of a long bone, usually caused by S. aureus
Brodie abscess
Most common cause of acute endocarditis; also affects in native valve (tricuspid valve) in IV drug abusers
S. aureus
Usually occurs in women who use tampons and in patients with nasal packing for epistaxis; no site of pyogenic inflammation and blood CS negative; presents with fever, hypotension, sloughing of filiform papilae -> strawberry tongue, desquamating rash and multi-organ development (>3)
Toxic Shock Syndrome: TSST-1, S aureus
On blood agar: whitish, non-hemolytic colonies
On gram stain: gram positive cocci in clusters
Calatase positive
Coagulase negative
Novobiocin sensitive
S. epidermidis
On blood agar: whitish, non-hemolytic colonies
On gram stain: gram positive cocci in clusters
Calatase positive
Coagulase negative
Novobiocin resistant
S. saprophyticus
Forms biofilms; MC cause of prosthetic valve endocarditis, septic arthritis in prosthetic joints and ventriculoperitoneal shunt infections
S. epidermidis
> 50% methicillin-resistant, tx: vancomycin
2nd MC cause of UTIs in sexually active women
S. saprophyticus
tx: TMP-SMX, quinolones
PYR test: positive
PYR test
(+): S. pyogenes or group D streptococci
(-): all other streptococci
Gram+ cocci Catalase negative Hemolysis beta Bacitracin sensitive? Resistant? Lancefield group?
Sensitive: group A, S. pyogenes (lancefield group A)
Resistant: group B, S. agalactiae (lancefield group B)
Fibrinolysin in Streptococci
Streptokinase - activates plasminogen
Strep pyogenes virulence enzyme which degrades DMA im exudates or necrotic tissue
DNase (Streptodornase)
Inactivates complement C5A seen in S. pyogenes
C5A peptidase
S. pyogenes toxins (5)
Erythrogenic toxin: prod scarlet fever
Streptolysin O (oxygen-labile): highly antigenic, cause AB formation
Streptolysin S (oxygen-stable)
Pyogenic exotoxin A: superantigen similar to TSST
Exotoxin B: protease that rapidly destroys tissue –> necrotizing fascitis
Lab tests for S. pyogenes infections
Anti-streptolysin O (ASO) titers: document antecedent pharyngitis
Anti-DNAse B titers: docu antecedent skin infection
Anti- streptokinase antibodies: decrease efficacy of streptokinase in managing MI
Honey-colored crusting on perioral blistered lesions; accumulation of neutrophils under stratum corneum; complication: poststrep GN
Impetigo contagiosa
MC bacterial cause of sore throat
S. pyogenes
Pastia’s lines, sandpaper-like centrifugal rash, strawberry tongue, fever, desquamation describe what disease? Bacterial agent?
Scarlet Fever
S. pyogenes
Erythrogenic toxin
Dick test for susceptibility
Tx for S. pyogenes infections
Pen G
Gram+ cocci in chains, beta-hemolytic, grows in LIM broth Catalase negative Bacitracin resistant CAMP test positive Lancefield group B
S. agalactiae (group B streptococci)
True or False: All pregnant women should be screened for GBS colonization during the first trimester
False; screening at 35-37 weeks AOG
S. agalactiae chemoprophylaxis of IV Penicillin or Ampicillin is given ___hrs prior to delivery
4 hours
Maybe the culprit in UTIs due to catheters and instrumentation; biliary tractinfections, endocarditis post GIT or GUT surgery
S. agalactiae
Bacteria responsible for marantic endocarditis in patients with abdominal malignancy
Streptococcus bovis
Gram+ cocci in chains, gamma (nonhemolytic) colonies
Catalase negative
Bile and optochin resistant
Lancefield group D
PYR test +
Hydrolyzes esculin in bile esculin agar (BEA)
Emterococcus faecalis (Group D streptococci)
Tx for E. faecalis
Penicillin + Gentamicin
If penicillin-resistant: vancomycin
If vancomycin-resistant: linezolid
Gram+ lancet shapped cocci in pairs (diplococci) \_\_\_\_\_? hemolytic Catalase \_\_\_\_\_? Bile and optochin \_\_\_\_\_? Positive/negative? Quellung reaction
ALPHA hemolytic
Catalase NEGATIVE
Bile and optochin SENSITIVE
POSITIVE Quellung reaction
Mnemonic for encapsulated bacteria
Some Killers Have Pretty Nice and Shiny Bodies S pneumoniae Klebsiella pneumoniae H influenzae P aeruginosa N meningitidis Salmonella typhi B group streptococci
MC cause of subacute and native valve endocarditis
Streptococcus sanguis
Viridans streptococci found in dental caries
Streptococcus mutans
Gram+ cocci in chains Alpha hemolytic Catalase negative Bile and optochin resistant Tx: PenG w w/o aminoglycoside (gentamicin)
Viridans Streptococci
Dry ground-glass surface and irregular edges with projections along the lines of inoculation
Medusa nead morphology
Bacillus anthracis
B. anthracis virulence factors which 1) inhibits a signal transduction in cell division and the other 2) mediates entry of the other 2 components into the cell
1) lethal factor LF
2) protective antigen PA
Combined: lethal toxin
B. anthracis protective antigen (PA) + Edema factor (EF) –>
Edema toxin
*edema factor EF (calmodulin-dependent adenylate cyclase)
Pulmonary hemorrhage is the most common cause of death in the following diseases (3):
Pulmonary anthrax
Weil’s syndrome
Congenital syphilis
Other name for anthrax infection when it spores are inhaled from animals
Woolsorter’s disease
Prolonged latent infection in inhalational anthrax lasts for ____ before rapid deterioration lasts for
2 months
DOC for cutaneous anthrax? Inhalational/ GI anthrax?
Cutaneous: Ciprofloxacin
Inhalational/GI: Ciprofloxacin or Doxycycline with one or 2 additional antibiotics (rifampin, vancomycin, penicillin, imipenem, clindamycin, clarithromycin)
Gram+ box car like rods which are nonmotile, spore-forming with medusa head morphology
B. anthracis
Aerobic, motile, gram+ spore-forming rods with spores usually found on rice grains withstanding steaming and rapid frying (reheated fried rice)
Bacillus cereus
