Part 2 Clinical Bacteriology (Staph) Flashcards
acid-fast rods are
Mycobacterium species
Mycoplasma species do not have
cell wall
don’t stain with Gram stain
which are spirochetes too thin to be seen when stained with
Gram stain
Treponema
Leptospira
What are intracellular bacteria and are difficult to visualise within the cytoplasm of the cell
Chlamydia
Rickettsia
What are intracellular bacteria and are difficult to visualise within the cytoplasm of the cell
Chlamydia
Rickettsia
Gram-positive cocci are
staphylococcus,
Streptococcus,
Enterococcus
Major Gram-negative cocci genus
Neisseria
Major Gram-positive rods genus
Corynebacterium,
Listeria,
Bacillus,
Clostridium,
Actinomyces,
Nocardia
Gram-negative rods in the Enteric tract That are pathogenic inside and outside tract
Escherichia,
Salmonella
Gram-negative rods in the Enteric tract that are Pathogenic primarily inside tract
Shigella,
Vibrio,
Campylobacter,
Helicobacter
Gram-negative rods that are Enteric tract organisms which are Pathogenic outside tract
Klebsiella–Enterobacter–Serratia group,
Pseudomonas,
Proteus–Providencia–Morganella
group,
Bacteroides
Gram-negative rods that are Respiratory tract organisms
Haemophilus,
Legionella,
Bordetella
Gram-negative rods that are Organisms from animal sources
Brucella,
Francisella,
Pasteurella,
Yersinia
Not readily Gram stained
Not obligate intracellular bacteria examples
Mycobacterium,
Mycoplasma,
Treponema,
Leptospira
Not readily Gram stained and are Obligate intracellular bacteria
Chlamydia,
Rickettsia
Which obligate aerobes grows best
in the 20% oxygen of room air and not at all under anaerobic conditions
Pseudomonas aeruginosa
Facultative anaerobes such as - can
grow well under aerobic and anaerobic conditions because
Escherichia coli
(Switches to fermentation in no air)
Aerotolerant organisms such as - can grow to some extent in air but multiply much more rapidly in a lower oxygen concentration.
Clostridium histolyticum
Microaerophilic organisms such as - require a reduced oxygen concentration (approximately 5%) to grow optimally
Campylobacter jejuni
obligate anaerobes such as - require an almost total absence of oxygen
Bacteroides fragilis
Clostridium perfringens
Many anaerobes use what rather than
oxygen as the terminal electron acceptor.
Nitrogen
main reason why the growth of anaerobes is inhibited by oxygen is the reduced amount (or absence) of
catalase
superoxide dismutase (SOD)
Catalase and SOD eliminate which toxic compounds formed during production of energy by the organism
hydrogen peroxide
superoxide
Give an example of a Microaerophile
Campylobacter jejuni
Anaerobic Spore-forming gram positive rod example
Clostridium
Anaerobic Non–spore-forming gram positive rod examples
Actinomyces,
Bifidobacterium,
Eubacterium,
Lactobacillus,
Propionibacterium
Anaerobic Non–spore-forming gram negative rod examples
Bacteroides,
Fusobacterium
Anaerobic Non–spore-forming gram positive cocci
Peptococcus,
Peptostreptococcus,
Streptococcus
Anaerobic Non–spore-forming gram negative cocci example
Veillonella
Examples of soil organisms
Clostridiumbotulinum
Clostridium tetani
Clostridiumperfringens
Diseases caused by members of the anaerobic normal flora are characterized by
abscesses
anaerobic normal flora
are characterized by abscesses, which are most frequently located in
brain,
lungs,
female genital tract,
biliary tract,
intra-abdominal sites.
Anaerobes are characterized by their ability to grow only in
an atmosphere containing less than 20% oxygen
important findings on physical examination that arouse suspicion of an anaerobic infection are
foul-smelling discharge,
gas in the tissue,
necrotic tissue.
infections that frequently involve anaerobes are
pulmonary aspiration,
bowel surgery,
abortion,
cancer,
human and animal bites
What specimens are appropriate that does not contain members of the normal flora to confuse the interpretation
blood,
pleural fluid,
pus,
transtrachealaspirates
Drugs commonly used to treat anaerobic infections are
penicillin G,
cefoxitin,
chloramphenicol,
clindamycin, metronidazole.
many isolates of the important pathogen B. fragilis produce β-lactamase and are thus
resistant to penicillin
aminoglycosides such as gentamicin are not effective against anaerobes because
they require an oxygen-dependent process for uptake into the bacterial cell
Microscopically, staphylococci appear in
grapelike clusters,
Microscopically streptococci appear
in chains
Biochemically, staphylococci produce
produce catalase (they degrade hydrogen peroxide),
whereas streptococci do not.
Staphylococcus aureus causes
abscesses
various pyogenic infections
endocarditis,
septic arthritis,
osteomyelitis
food poisoning,
scalded skin syndrome
toxic shock syndrome
most common causes of
hospital-acquired pneumonia,
septicemia,
surgical-wound infections is
Staphylococcus aureus
Staphylococcus aureus is an important cause of skin and soft tissue infections, such as
folliculitis,
cellulitis,
impetigo
most common cause of bacterial conjunctivitis
Staphylococcus aureus
Methicillin-resistant S. aureus (MRSA) is the most common cause of
skin abscesses
What is important cause of pneumonia, necrotizing fasciitis, and sepsis in immunocompetent patients
Methicillin-resistant S. aureus (MRSA)
Staphylococcus epidermidis causes
prosthetic valve endocarditis and
prosthetic joint infections
What is the the most common
cause of central nervous system shunt infections and an important cause of sepsis in newborns
Staphylococcus epidermidis
What causes urinary tract infections, especially cystitis
Staphylococcus saprophyticus
What syndrome is a disease of unknown etiology that may be caused
by certain strains of S. aureus.
Kawasaki syndrome
spherical gram-positive cocci arranged in
irregular grapelike clusters are
Staphylococci
All staphylococci produce …
catalase
no streptococci
produce catalase
What does catalase do
degrades H2O2 into O2 and H2O
Catalase is
an important virulence factor
Bacteria that make catalase can survive
the killing effect of H2O2 within neutrophils.
Scalded skin syndrome. Note widespread areas of “rolled up” desquamated skin in infant, Caused by
exotoxin produced by Staphylococcus aureus
Impetigo. Lesions of impetigo are crops of
vesicles with a “honey-colored” crust Impetigo is caused by
either Staphylococcus aureus or Streptococcus pyogenes