Vernon wanted to determine the colony forming units of bacteria per gram of soil in their school garden. He obtained 10 grams of soil from the garden and serially diluted it. He spread plated the samples of 10-3, 10-4, and 10-5 After incubation, the colony counts are as follows: 1:1000 1:10 000 1:100 000 TNTC, TNTC* 222, 217 19, 13 *Too numerous to count Calculate for the CFU/g of bacteria. Show your solution and express your final answer to 2 significant figures.

Vernon wanted to determine the colony forming units of bacteria per gram of soil in their school garden. He obtained 10 grams of soil from the garden and serially diluted it. He spread plated the samples of 10-3, 10-4, and 10-5 After incubation, the colony counts are as follows: 1:1000 1:10 000 1:100 000 TNTC, TNTC* 222, 217 19, 13 *Too numerous to count Calculate for the CFU/g of bacteria. Show your solution and express your final answer to 2 significant figures.

Basic Clinical Laboratory Techniques 6E

6th Edition

ISBN:9781133893943

Author:ESTRIDGE

Publisher:ESTRIDGE

Chapter7: Basic Clinical Microbiology

Section7.4: The Gram Stain

Problem 2RQ

See similar textbooks

Similar questions

Vernon wanted to determine the colony forming units of bacteria per gram of soil in their soil garden. He obtained 10 grams of soil from the garden and serially diluted it. He spread plated the samples of 10, 104, and 105. After incubation, the colony counts are as follows: 1:100 000 19, 13 1:1000 1:10 000 TNTC, TNTC 222, 217
Kousei works at a company that produces sweetened condensed milk. If one or more samples exceed 104 bacterial CFU/mL (or CFU/g) the entire lot produced will be rejected. Kousei's boss, Kaori, wanted to know if the lot passed the FDA guidelines. The following bacterial counts were obtained after serial dilution and pour plating of the samples: Type of Dilutions plated 10-4 10-³ 10'5 Colony Plate 1 Plate 2 Plate 1 Plate 2 Plate 3 Plate 1 Plate 2 Plate 3 Plate 3 244 Bacteria 288 251 99 81 75 24 21 15 Based on the bacterial counts obtained, will the lot be rejected? Yes, because the computed CFU/mL is 2.5 x 10^7 OYes, because the computed CFU/mL is 3.0 x 10^6 No, because the computed CFU/mL is 3.0 x 10^3 No, because the computed CFU/mL is 2.5 x 10^3 OYes, because the computed CFU/mL is 3.8 x 10^5 O No, because the computed CFU/mL is 3.0 x 10^3 O Information is lacking so CFU/mL cannot be computed
One hundred microliters (0.100 ml) of a 10-5 dilution of a bacterial suspension plated on an agar plate gave rise to 229 distinct colonies. What was the concentration of bacteria in the original, undiluted suspension?
A serial dilution of overnight E.coli culture was performed by pipetting 1ml of a bacterial culture into a 9 ml LB medium. After this, from 10-4 and 10-5 dilution tubes 100µl were plated onto LB agar plates. Upon overnight incubation at 37°C, 200 colonies were counted in 10-4 and 22 colonies were present on 10-5 plates. How many colony-forming units were present per ml of the original culture? If the formula for CFU/ml =no. Of colonies/dilution factor*volume of culture plate
To determine the number of cells in a pure culture of Klebsiella pneumoniae, you have performed a serial dilution using three tubes of sterile saline (9.9 ml each). A sample of 0.1 ml from the culture was added to tube 1. Similarly, 0.1 ml from tube 1 was used to inoculate tube 2, and tube 3 was inoculated using 0.1 ml from tube 2. A nutrient agar plate was then inoculated using 0.1 ml from tube 3 and incubated overnight. The next day, 92 colonies were observed on the plate. How many cfu/ml were in the original culture? Using a Petroff-Hauser counting chamber, the number of cells in the same culture was estimated to be 8.5 • 109 cells/ml. How can you explain these results?
The images attached are the photos of bacteria in yoghurt under a misroscope. According to these images and your own knowledge, can you make a biological drawing of bacteria in yoghurt ( in a circle) and identify the types of bacteria accurately?
A laboratory technician performed a series of 10 fold serial dilutions shown below. he plated 0.1 mL from each dilution tube onto NA and got the follow numbers per plate dilution 1:10 1:10 1:100 1:1000 1:10000 1:100000 colony count >1000 >1000 808 303 38 3 calculate the concentration of bacteria in the undiluted stock (in CFU/mL)
There are so many microbes in a single mL of culture, it is very difficult to perform one dilution to produce countable cells. Microbiologists need to perform a dilution series, where multiple dilutions are performed in sequence to arrive at the correct dilution. Dilutions are cumulative. Multiple the series of dilutions together to find the final dilution value. If 3 serial dilutions are performed, each with a value of 0.01, what is the cumulative dilution? Express your answer as an exponent, e.g. 0.1 would be 1e-1 and 0.01 would be 1e-2
A bacterial culture was grown for 12 hours. At 4-hour interval, the culture was sampled to determine the population of the culture, by transferring 25 ml of the suspension to 225 ml 0.90% NaCl. Three consecutive dilutions were further made by using I ml aliquot in 9 ml of 0.90% NaCl. One ml from each dilution was plated in each of duplicate plates. The following table shows the results of the plating method. 田 Sampling COUNTS 1st dilution 54; 61 2nd dilution 3rd dilution 4h dilution 1st 3; 7 0; 0 0,0 2nd TNTC TNCT 242: 233 28: 37 3rd TNTC TNTC INTC 249-246 * TNTC = Too numerous to count i. Illustrate the dilution series used and label the final dilution of each dilution. ii. Determine the bacterial count (CFU/ml) every 4 hours of incubation for 12 hours. Show all computations.
You are given a 1 gram soil sample of unknown bacterial load. After doing 10-fold serial dilutions of the soil in sterile water, 100 uL volumes are taken from each dilution for preparation of pour plates. Following incubation, each half of the 10-8 plate has 46 colonies.a) What was the dilution factor?b) How many bacteria were present in the soil?2. Staphylococcus aureus divides every 20 minutes. A culture begins with 10 bacterial cells.a) After 5 hours, how many generations have occurredb) After 5 hours, how many bacteria are present?3. How many milliliters would you need to prepare a 10-2 dilution from a 10ml starting culture?
A culture of Staphylococcus is diluted as follows:(1) 20mL are added to 80mL of water.(2) 10uL from (1) are then added to 9.99mL of water.(3) A 10-2 dilution is made from tube # (2).(4) 100uL from (3) are plated for a pour plate and incubated. There were 34 colonies counted on one quarter of the plate following incubation. a) What was the overall dilution?b) How many cfu/mL were present in the original culture?
You have conducted serial 10-fold dilutions and measured the cfu (colony forming units) of a Streptococcus pneumoniae culture and also the pfu (plaque forming units) of a phage (virus) that infects the bacteria. You counted 5 cfu in a 0.4 ml sample of a 106 dilution of the bacterial sample. You then counted 50 plaque-forming units (pfu) in a 0.25 ml sample of a 108 diluted sample of the phage culture. What are the cfu/ml of the S. pneumoniae and pfu/ml of the phage cultures before dilution? 5 x 106 cfu/ml and 2 x 109 pfu/ml 4 x 107 CFU/ml and 2 x 109 PFU/ml 1.25 x 108 cfu/ml and 10 x 1010 pfu/ml 1.25 x 107 cfu/ml and 2 x 1010 pfu/ml