classification of bacteria Flashcards
difference in G+ and G-
G+ retains the purple die bc only two layers of membrane/walls
G- doesn’t retain dye (pink) and has 3 layers of walls/membranes
G+ bacteria
staph, strep, enterococcus, pepto, listeria monocytogenes, corynebacterium diptheriae, bacillus anthracis, clostridium
staphlococcus
MRSA, MSSA, VRSA, cocci/faculative/grows in clusters
streptococcus
PRSP (pen resistant s. pneumoniae), cocci/faculative/grows in chains
enterococcus
VRE (vanc resistant enterococcus), cocci/faculative/grows in chains
peptocccus/peptostreptococcus
cocci/anaerobic
listeria, cornyebacterium, bacillus anthracis
bacilli/faculative
clostridium
anaeroboic/bacilli/spore forming
G - bacteria
neisseria, moraxella catarrhalis, pseudomonas, acinetor, stenotrophomas, burkholderia, vibrio cholera, enterobacteriaeae (E. coli, klebsiella pneumonia, proteus, enterobacter, serratia, citrobacter, salmonella, shigella, haemophilius influenzae, campyloacter, helicobactor pylori, bartonella, bacteroides fragilis
hard to treat/ often resistant antimicrobials
SPACE Serratia marcescens psudomonas aeruginosa Acinetobacter Citrobacter Enterobacter
fastidious (slow growing) gram - bacteria associated with endocarditits
Haemophilus Aggregatibacter Cardiobacterium Eikenella Kingella
cocci/faculative/G-
neisseria, moraxella catarrhalis
bacilli/aerobic/G-
psudomonas aeruginosa acientobacter baumanni, stentrophomonas maltophilia, burkholderia
bacilli /faculative/G-
vibrio cholera, enterobacteriaeae (e coli, serratia, citrobacter, salmonella, shigella, proteus)
bacilli/aerobic/fastidious/G-
haemophilus influenzae, campylobacter, H. pylori, bartonella
bacilli/anaerobic/G-
bacteroides fragilis
atypical bacteria
mycoplasma, mycobacterium (tb, leprae), chlamydia, rickettsia, legionella pneumophilia
can you easily identify atypical bacteria using the gram stain?
no cell wall so you can’t do a gram stain, cell wall with a different composition, won’t give you any information
catalase test
breakdown of H2O2 to H2O and O
catalase positive = staphylococcus
catalase negative = streptococcus
coagulase test
converts fibrinogen to fibrin
used to differentiate staphyloccocus spp
coagulase positive - staphylococcus aureus
coagulase negative - staphylococus epidermis, staphylococcus saprophyticus (will just say CoNS)
hemolysis test
strep species classified on their ability to hemolyze RBC
alpha hemolytic
RBC intact, oxidize iron of hemoglobin, green/brown discoloration, strep pneumoniae and virdidans strep
beta hemolytic
complete RBC, clear zones around the colonies, strep pyogens, strep agalactiae
gamma hemolytic
no hemolysis, strep gallolyticus (formally s. bovis)
lancefield stereotypes
used to distinguish between strep and enterococcus, bacteria are grouped based on their carbs present on the bacterial cell wall
group A: strep pyogens
group B: strep agalactiae
group D: strep gallolyticus (S. bovis)
none: strep pneumonia and virdans stretptococcus
E facalis vs E faecium
facalis: causes majority of enterococcal infections, less drug resistant
faecium: causes a minority of enterococci infections, more drug resistant
lactose fermentation test
ability to ferment lactose and used to differentiate the gram - rods
lactose fermenters
e. coli, klebsiella, enterobacter, citrobacter, serratia
lactose non fermenters
pseudomonas, proteus, hemophilus, salmonella, shigella, stenotrophomonas, acinetobacter
benefits of the normal flora
compete with invading pathogenic bacteria for nutrients and space, healthy flora prevent infections, helps metaboliz non digestible carbs, provides VK and VB
site of infection of gram positive cocci
skin, soft tissue, heart valves, lung, bones, joints, hardware such artificial joints, indwelling of lines
site of infection of gram negative rods
intraabdominal organ, geniourinary system
HAP: hospital acquired pneumonia
VAP: ventilator acquired pneumonia
anaerobes site of infection
lung abcess, oral cavity, aspiration pneumonitis, intrabdominal organ/space, deep skin/soft tissue infections, diabetic food tinfections
atypical site of infection
community acquired pneumonia
