gram neg bacilli Flashcards
liseria monocytogenes
only species considered to be of public health significance
-food borne pathogen
-culture for ID
-ELISA or PCR
-CAMP reaction
-infects cold foods
listeria seeligeri and ivanovii
implicated in humans on rare occassions
l. monocytogenes morphology
-large, gram pos
-motile rod
-over 200 strains
genus lactobacillus
lactic acid production
-vagina, intestinal tract, and mouth
-make yogurt, pickles
genus listeria
contaminates dairy products
-survives in phagocytic cells
-infection in preg woman can cause stillbirth or fetal damage
invasvie listeriosis
-preg, >65, immunocompromised
-1-4 weeks after infection
-food poisoning like symptoms
listeria transmission
-facultative anaerobe
-acid but not gas producing from glucose
-psychrotroph
listeria growth characteristics
-resistant to NaCl
-tolerate low pH
-not inhibited by CO2
-can survive freezing and drying
-ideal is chocolate agar, will grow on blood
listeria pathogenesis
-listeriolysin O to degrade the vesicles and go into the cytosol
-ActA to initiate massive actin polymerization to form actin rockets to go into nearby cells
-starts in GI tract and spreads to liver and spleen leading to dissemination
CAMP
distinguish strep agalactiae from other beta hemolytic streps
reverse CAMP
-pos group B strep streaked again c. perfringens
-bow tie zone of hemolysis
lecithinase test
-egg yolk agar
-pos: white, opaque zones extending into the medium surrounding colonies
-neg: absence of pos reaction
positive lecithinase orgs
-c. perfringens
-l. monocytogenes
-psuedo aeruginosa
-s. aureus
l. monocytogenes ID
-round, smooth, translucent colonies
-narrow zone of beta hemolysis
-colonies give blue-green color under reflective light
-catalase pos
-VP pos
enterobacteriaceae
-small, straight rods
-gram neg
-soil, water, human/animal bowels
-spore forming
-motile (except shigella, klebsiella & yersinia)
-facultative anaerobe
-oxidase neg
-catalase pos
-glucose ferment
-nitrate reduction
-ferments carbs (anaerobic pathway)
catalase pos organisms
-staph
-nocardia
-pseudomonas
-listeria
-aspergillus
-candida
-e. coli
e. coli pathogenicity
-most prevalent enteric bacillus
-aerobic and non-fastidious
-pathogenic strains frequent agents of infantile diarrhea & neonatal meningitis/septicemia
e. coli virulence
-adhesions. pili or fimbriae
-capsule
-iron capturing ability
-outer membrane proteins
-O, H, K antigens
-K1 strong association with meningitis in neonates
-O & H characterize EHEC strains (O157 : H7)
e. hermannii
-yellow pigmentation, isolated from CSF, wounds and blood
e. vulneris
wounds
enterotoxigenic e. coli
severe diarrhea due to heat-labile toxin and heat-stable toxin.
-stimulate secretion and fluid loss
-has fimbriae
enteroinvasive e. coli
causes inflammatory disease of large intestine
enteropathogenic e. coli
linked to wasting form infantile diarrhea
enterohemorrhagic e. coli
O157 : H7
-hemorrhagic syndrome and kidney damage
-shiga toxin producing e. coli
benchtop e. coli ID
-grey, beta hemolytic colonies
-short gram neg bacilli
-lactose fermentation on MAC
-spot indole pos
-pink on MAC, not pink on MAC w/ sorbitol ( O157 : H7)
-ferments glucose, lactose, trehalose, and xylose
-indole & methyl red pos
-does not produce H2S (urea neg)
-simmons citrate neg
-motile
-VP neg
-oxidase pos
aerobic non fermenters
-pseudo aeruginosa
-burkholderia cepacia
-stentrophomonas maltophilia
-opportunistic pathogens
-obligate aerobes
-do not ferment sugars
-motile
-oxidase pos
pseudo aeruginosa
-grape like odor
-bluish-green due to pyocyanin & fluorescein
-oil eating bacteria, refuse to die
-hospital infections, VAP immunocompromised pts, multi antibiotic resistance (pen, ampi, ceftriaxone, etrapenem)
pseudo aeruginosa characteristics
-gram neg rods
-motile
-obligate aerobes
-oxidase/catalase pos
-non fermenter (glucose oxidatively)
-beta hemolytic
pseudo flourescences
-pyocyanin production on pseudocel agar
-oxidase pos
-alk/alk
-pyocyanin production
pseudo stutzeri
-flat wrinkled yellow pigmented colonies on BA
-oxidase pos
-dextrose oxidizer
-alk/alk
-motile
-citrate pos
-nitrate pos
pseudo putida
-pyocyanin on pseudocel agar
-oxidase pos
-alk/alk
-pyocyanin production
pseudo diseases
-nosocomial infections
-folliculitis
-otitis externa
-eye infections
-endocarditis
-ecthyma gangrenosum: hemorrhagic lesions w/ disseminated infections, elastase production by aeruginosa
-pneumonia in CF pts
shigella
-gram neg
-non motile
-non lactose fermenter
-parasite of human digestive tract
-infective dose is low
-diarrhea-inducing enterotoxin
-cause a server form of dysentery (shigellosis)
s. dysenteriae
produce a more serious disease than other species
s. flexneri
most commonly isolated in developing countries
s. boydii & sonnei
cause a mild form of diarrhea, pts are ambulatory
shigellosis
-localized to intestines with formation of micro-absecesses in wall of large intestine and terminal ileum leading to superficial ulceration
-highly transmissable
-dysnteriae produces an exotoxin which acts as an enterotoxin & neurotoxin
presumptive ID of salmonella
-grey white colonies on BA, lactose on MAC
-H2S pos (black on HE)
-lysine decarboxylase pos
-citrate pos = non typhi
-citrate neg = typhi
yersinia enterocolitica
bacteria enter small intestine, lymph inflammation, survive in phagocytes. mimics appendicitis
-grey white entire colonies on BA
-non lactose fermentation on MAC
-alk/acid
-indole pos
-citrate neg
-urea pos
presumptive shigella ID
-non pigmented colonies on MAC
-inert to most biochemicals
-ornithine decarboxylase pos
presumptive ID of yersinia enterocolitica
-grey, white entire colonies on BA
-non lactose fermentation on MAC
-alk/acid
-indole pos
-citrate neg
-urea pos
presumptive ID of serratia marcescens
grey entire colonies on MAC
-non lactose fermenting
-red colonies on MAC
-DNase pos
-motility pos
only clinically significant one
common enterobacteriaceae considered opportunistic pathogens
e. coli
proteus
enterobacter
klebsiella
citrobacter
serratia
non motile enterobacters
klebsiella
shigella
yersinia
klebsiella overview
capsule, adhesions & iron capturing ability
-causes pneumonia & permanent lung damage
-alcoholics at risk
-gram neg, nonspore forming
-nonmotile
-ferment lactose
-urease pos
-prominent capsule
-indole pos
-capsule
presumptive ID of klebsielle pneumoniae
smooth convex mucois colonies on BA
-lactose ferments on MAC
-indole neg
-urease, citrate, VP pos
bulkholderia cepacia
-opportunistic in CF pts
-extremely drug resistant
ID of burkholderia pseudomallei
-buff yellow wrinkled colonies on BA
-pink on MAC
-yellow on spot swab
-oxidative use of carbs
bulkholdera pseudomallei ID
-buff yellow wrinkled colonies on BA
-pink on MAC
-yellow on colony swab
-of carbs
-arginine pos
-nitrite reduction
bulkholderia cepacia
same as all others
-non fermenter
-lysine pos
-maltose sucrose pos
moraxella ID
-grows on chocolate & blood
-gram neg cocci or short coccobacilli
-asacchorolytic for carbs
-oxidase, catalase, DNase pos
-nitrite reduce
acinetobacter baumannii
-white entire opaque convex colonies on BA
-entire smooth to wrinkled colonies on MAC
-gram neg coccobacilli
-oxidase neg
ferments glucose and lactose
-can be extremely drug resistant
moraxella diseases
sinunitis
bronchopneumonia
endocarditis
meningitis
ID of aeromonas sobria
-small opaque grey white & beta hemolytic on BA
-entire smooth pink on MAC
-DNase pos
-oxidase pos
-indole pos
-lysine & arginine pos
-acid from sucrose, arabinose & mannitol
aeromonas syndromes
GI diseases
-chronic diarrhea in adults
-shigella with blood & wbc in stool in children
-wound infections
-opportunistic in immunocompromised
ID of plesiomonas shigelloides
grey-yellow entire smooth colonies on choc & BA
-DNase neg
-indole pos
-oxidase pos
-lysine, arginine, ornithine pos
-acid from glucose & inositol
vibrio cholerae virulence factors
-cholera toxin
-toxin coregulated pilus
-adhesion factor
-accessory cholera enterotoxin
-neuraminidase
-zonnula occludens toxin
vibrio cholerae ID
smooth entire creamy grey-yellow colonies on BA
-yellow colonies on TCBS
-short gram neg bacilli
-flagellar stain: small plump gram neg with single polar flagella
-ONPG pos
-lysine, ornithine decarboxylase pos
-indole pos
-acid from glucose and sucrose
campylobacter jejuni
-slow growing at 37, best at 42, no growth at 25
-slender gram neg bacilli, spiral
-indoxyl acetate pos
-hippurate pos
-naladixic acid
campy upsalinesis ID
-entire convex smooth yellow colonies
-curves spiral yellow bacilli in fluorescent stain
-indoxyl pos
-hippurate neg
-nitrate pos
campy coli ID
-curved spiral yellow bacilli in fluorescent stain
-indoxyl pos
-hippurate neg
-nitrate pos
grows at 25
campy jejuni
-curved gram neg rods
-microaerophilic
-grows at 42
-oxidase pos
-bipolar flagella
salmonellas
-motile
-does not ferment lactose
-produces H2S
pathogenesis of salmonella
-invade host cells and survive in macros
-SPI-1: inject salmonella invasion proteins into M cells
-SPI-2: involved in systemic infection
-resistant to stomach acid and phagosomes
h. pylori
-gram neg bacilli
-fastidious growth requirements
-require CO2 for growth
-charcoal medium
-unipolar flagella
h. pylori ID
pinpoint grey colonies on BA or choc
-small curves slightly plump gram pos bacilli
-catalase pos
-oxidase pos
-urease pos
