Water Bacteriology

Question 1

Contaminants of fecal origins ( because of unsanitary practices of that particular area)

Answer 1

Bacillary dysentery
Typhoid
Cholera
Parathypoid fever

Question 2

Common water borne enterics

Answer 2

Shigella dysenteriae
Campylobacter jejuni
Salmonella typhi
Vibrio cholerae

Question 3

Indicates the presence of e.coli

Answer 3

Coliform formation

Question 4

Presumptive test

Answer 4

Lactose fermentation broth with inverted Durham tube

Question 5

Confirmed test

Answer 5

EMB or ENDO agar

Question 6

Completed test

Answer 6

Lactose broth and nutrient agar

Question 7

Enterobacteriae, specifically your e-coli produces

Answer 7

Gas

Question 8

used to detect production of gas

Answer 8

e.coli

Question 9

Formation of e. coli under emb on ENDO agar

Answer 9

pink with a metallic sheen

Question 10

utilized for completed test, which is used to completely identify your coli forms coming from presumptive and confirmed test

Answer 10

lactose broth and nutrient agar

Question 11

for presumptive test, incubate sample ___ hours at 37 degree celsius

Answer 11

48 hours

Question 12

positive result in presumptive test

Answer 12

presence of gas

Question 13

for confirmatory test streak ___ from positive tube and incubate ___ hours, 37 degree celsius

Answer 13

EMB, 24 hours

Question 14

positive confirmed test

Answer 14

• typical coliform colonies, water nonpotable
• gram neg short bacilli

Question 15

the absence of gas in all lactose broth tubes indicates

Answer 15

coliforms are absent and water is safe to drink

Question 16

if gas is present only after 48 hours

Answer 16

the gas is probably not due to coliforms. further testing

Question 17

if gas occurs in the durham tube of one or more lactose broth after 24 hours

Answer 17

water is presumed unable to drink

Question 18

pathogens that can contaminate water and cause disease

Answer 18

cholera (vibrio cholera)
typhoid fever (salmonella typhi)
dysentery (shigella dysenteriae)

Question 19

types of bacteria used to detect and estimate the level of fecal contamination of water

Answer 19

indicator bacterium

Question 20

characteristics of coliforms

Answer 20

gram negative
facultative anaerobic
non spore forming rods that ferment lactose

Question 21

is the basis for determining the total coliform count in water sample

Answer 21

lactose fermentation with acid and gas

Question 22

bacterial examination of water tests

Answer 22

presumptive test, confirmed test, completed test, IMViC tests

Question 23

presumptive test is also used to determine ____ of coliforms present in 100 ml water

Answer 23

Most Probable Number (MPN)

Question 24

plates of Levine EMB agar inoculated form positive tubes (gas producing tubes) to see if the organisms that are producing gas are gram neg (another coliform characteristic)

Answer 24

confirmed test

Question 25

determines if organisms are gram negative (media inhibits (media inhibits gram pos bacteria)

Answer 25

confirmed test

Question 26

coliforms in emb will inhibits what colonies?

Answer 26

large blue black colonies with a green metallic sheen for e. coli under

Question 27

determines if the isolate from the agar plates match our definition of a coliform

Answer 27

completed test

Question 28

if gas is produced and a slide is made from a slant, this confirms the presence of gram negative, non spore forming rods the presence of coliform is certain

Answer 28

completed test

Question 29

• final test to separate e. coli and e.aerogenes
• previous tests just indicate that coliforms are present, not which organism

Answer 29

IMVic tests