1. Counting Bacteria

2. Serial Dilutions
Because of their very ______ ______, counting the number of bacteria in a sample can be _________
Although _______ _______ are possible with a ______________, they require a lot of time and ___________

3. Why Count the Number of Bacteria??
________ _____________:
How effective drugs are in killing microorganisms?
___________________:
How many MO in CSF, blood, urine
___________ ____________:
- Contaminants in food, milk, water

4. Total Cell Count
The most common method of _______________ the total microbial cells (______ ___ _________)
The ______ ___________ of cell suspension in a __________ _____________ of known _______ using a ________________

5. Total Cell Count – Both living and dead MO
Disadvantage: ____________________________________________________________________________________________________________
Advantage: _____________________________________________________________________________________________________________

6. Total Cell Count – Both living and dead MO
Neubauer ___________ ___________
Special _______ ____ _______ _______, microscopic marks on slide, known _________

7. Counting Chamber

8. Counting Chamber Use special ______________ ____ _____________________
Count specific areas of __________________, multiply by __________________ ______________

10. Instrumentation * _____________________ (Light Meter)
Each single ____ stops some ______ from ____________________________________________
One side _____ ________, then test tube containing MO, other side _______ ________________
Needle reading from scale, then ________________ _____________ telling # of __________________________________________

14. Coulter Counter Another method for _____________ _____________
An electronic instrument “_____________ _________”
Has a tiny tube (_____ ______ _____________) that lets through only one cell at a time

15. Viable Cell Count –
Living Cells Only

16. Viable Count – Living Cells only
An easier method is to ______ ________ _____ __ _____ ______ (nutrient agar plate) and count the number of ________ _____ ______
If the bacteria are ______ ____ ______, each bacterial cell in the original sample should produce a _______ _______

17. Serial Dilutions
Bacterial samples must be _______ considerably to obtain ___________ ___________
To determine the ________ ___ ______ in a bacterial culture carry out _______ ____________

18. Serial Dilutions
Bacterial cell numbers are usually _______ _____ _____________________________
Plating out this sample, undiluted, would lead to the creation of a ___________________
Bacterial Lawn - many individual bacteria colonies that are ______________________ ____________________________________

20. Serial Dilutions Bacterial cell numbers _____ __ __ _______
This is done by ______ ________ the amount of bacteria you have in your sample
A ______ _________ of bacteria sample is mixed with a _____ _______ (sterile broth or water), and then _______ ___________ are made

22. Serial Dilutions
A small amount of _____ ___ ____ _______ _________ ________ is then spread onto an ______ ________
The numbers of bacterial colonies that ______________________________

23. Serial Dilutions
Work ___________ using multiplication with the “___________ ____________”
________ ________ - the ______ ___ ______ that you have diluted the bacteria sample with the diluent solution
Make a determination of the numbers of bacteria in ______ ________ _________.

24. Serial Dilution

26. Serial Dilutions *Make ________ _____________
*Spread a small amount from each tube onto _______ _______
*Culture bacteria for a ________ __ _________
*Count colonies
________________________________

29. Membrane Filtration
________ __________ can also be used to determine the ________ _______________
In this method ______ _____ ___________ onto membrane filter which is then placed over a ________ ______ __________.

30. Membrane Filtration
The methodology is similar to conventional _______ ________ _______________.
Membranes have a printed millimeter ________ and colonies can be counted under a _________ _________________.

33. Factors essential for __________ ________
--proper ________________
--proper ___________________ (space, temperature)
--No inhibiting factors
Factors that _____________________ __________________________________________
--lack of _____________
--lack of __________ __________________
--presence of an ___________ __________