parasite that may be present in drinking water include..
the parasite, cryptosporidium and giardia the virus norovirus, coliform and non-coliform pathogens, salmonella, shigella, campylobacter. E coli, and Vibrio cholerae
what disease you can get from the pathogen present in water?
diarrhea, dysentery, and possibly sepsis and death.
the most common causes of recreational and drinking water gastrointestinal outbreak in US, these pathogen are chlorine resistant.
members of Enterobacteriaceae
characteristic of enterobacteriaceae
facultative anaerobic, gram negative rods=which produce acid and gas from the fermentation of lactose.
live in gastrointestinal tract and typically enter a body of water with the introduction of fecal material. the presence of this bacteria indicates the presence of fecal contamination and the possible presence of pathogens
a presumptive or screening test for the presence of gas producing coliforms after incubating for 48 hours at 35C in lactose broth
multiple tube fermentation test.
example of microbes that may be present to produce gas but are not coliform
clostridium perfringnes, enterococcus faecalis
the presence and types of coliform in water sample is confirmed using what method?
selective and differential media in the confirmed test.
this media typically select for the growth of gram negative bacteria, inhibiting most gram positive bacteria and differentiaten lactose ferementers(coliform) from those gram negative that do not ferment lactose_noncoliform)
selective and differential media
agar used in selective and differential media
Eosin Methylene Blue, MacConkey agar, Hektoen Enteric agar
contain dye eosin Y and methylene blue which inhibit gram positive bacteria. these dye also react with the acid produced by lactose fermenters
eosin methylene blue
produces a striking metallic green sheen due to the excessive acid production from lactose fermentation.
those fermenters producing less acid turn to what color?
medium pink to dark purple
differentiating salmonella and shigella from other enterics
inhibit the growth of most gram positive bacteria
enterics fermenting any of the three available three sugars such as E coli are typically yellow to pinkish orange and non-fermenters such as shigella are typically blue-green.
will react with any H2S produce to form a black ferrous sulfide
media that has ferric ammonium citrate
typically produce h2S and colonies will be black
is also use to differentiate salmonella and shigella from other enterics. the media contains bile salt and crystal violet which gram positive
turns lactose fermenters pink and non-fermenters are colorless.
neutral red indicator
example of gram positive cocci. these bacteria may be normal flora of the hman nares and skin, and gastrointestinal tract
staphylococcus aureus9typically cluster in gram stain), enterococcus fecalis(chains in gram stain).
causes abscesses and has the ability to invade and cause systemic disease such as acute endocarditis, necrolytic pneumonia, and toxic shock syndrome
causes thousands of death per year in the US.
Methicillin resistant staphylococcus aureus
generally not as serious as S aureus but are also associated with nosocomial infection.
is a common cause of blood stream infections, as weel as being resistant to antibiotics, such as vancomycin resistant enterococcus
gram positive cocci and catalase positive
is one enzyme used by aerobic and facultative bacteria that catalyzes this reaction 2 H202- @ H20 +02
a microaerophilic and does not produce catalase
typically hemolytic on blood agar as it produces several hemolysis. it is also halotolerant allowing it to grow on salt plates and it ferments mannitol. finally, it produces the coagulase enzyme which causes coagulation of plasma by converting fibrinogen to a fibrin clot
ma be normal flora of the vaginal tract. can cause UTI. typically not hemolytic on blood agar, is halotolerant and ferments mannitol
is a common member of skin flora but may be associated with hospital acquired blood stream infection. it is non-hemolytic on blood. is halotolerant, but does not ferment mannitol, and is coagulase negative