Final Mirco Lab Test
Gram negative, aerobic or faculative anaerobic, non-sporing bacilli that ferment lactose with gas within 24-48 hours at 35C.
Standard Water Analysis
1) Done to narrow the identification of E. coli
2) Rule out false-positive indicator organisim such as E. aerogenes
test is divided into 3 parts
3 Parts of Standard Water Analysis
Large Durham tube containg double-strength phenol red lactose broth. Turns
Positive Presumptive tests
Any tubes showing acid and gas production.
Coliform bacteria ferment lactose and produce gas. Thus, if this is a coliform bacteria is present we will see a color change to yellow and an air bubble in the Durham tube.
-Still not sure if E.coli is present
Using an EMB Agar Plate (Eosin Methylene Blue) agar plate.
Use streak-plate method. A positive test confirms the presense of E. coli : A green metallic sheen .
Estimated cells per ml
# colonies (colony-forming units) * dilution factor
99* 10,000 = 990,000 cells/ml
Succesive dillutions for milke plate
We do successive dilutions in order to get a milk plate with an adequate number of colonies < 30 Colony Formning Units eqauls too few > 300 CFU equals to many.
Bacteria Plate Count
Indicator of quality of milk sample
A diesease in milk that all forms of pasturization kills
Direct Methods of transmission
personal contact with someone who has the disease
Indirect Method of transmission
consuming contaminted food and contact with fomites
inanimate objects that carry organisms that can cause a disease. ie hospital bedding
organism carried on legs or othe body parts of arthropod vector
arthropod itself is infected and orgnaism becomes part of its life cycle.
indirect transmission method
hinge or joint- footed animal
Organisim which carries diease agent from one host to the next.
- many are decomposers and break down dead, organic matter
Must ingest carbon mollecules
zygospores form where plus and minus strands meet
Hyphae produce diploid
Sporangiospores in sacs called sporangia
Some are human pathogens / opportunists (take advantage of immunocompromised hosts)
Ex: Rhizopus stolonifer (black bread mold) , Mucor
Sexual: Ascospores (in sacs - ascus)
Asexual: Conidiospores (not in sacs - naked)
Includes non-pathogens, opportunits and pathogens
1) Candida albicans (oral thrush, vaginal yeast infection, systemic candidiasis)
2) Saccharomyces cerevisiae: yeast used to make bread and alcohol
3) Penicillium notatum: Penicillin
4) Aspergillus niger
asexual: most do not have asexual stage
found underside of mushroom cap (in the gills)
No sexual stage
many fungi previously placed in group have been moved to another group.
hyphae that have cross-walls / septa
no cross-walls / septa
grow along substrate