Question

In: Biology

The following table outline the unknown gram-positive bacterium that was isolated using these biochemical test: Catalase...

The following table outline the unknown gram-positive bacterium that was isolated using these biochemical test:

Catalase Test (positive/negative)

Coagulase test

(positive/negative)

Oxidase test

(positive/negative)

Positive

Negative

Positive

1) Briefly describe which gram-positive bacterium it was and why was it?

2) In the mixed culture, you isolated a Gram-positive bacterium. Describe the significance of its isolation from a clinical sample from:

a) A normally sterile site (e.g. blood, joint aspirate)     […../5]

b) A non-sterile site (e.g. wound swab, throat swab) [……/5]   

Solutions

Expert Solution

1) The organism is Staphylococcus sciuri

i. Catalase test is done to distinguish Staphylococcus (produces catalase and thus gives positive result with the test) between Streptococci ( do not produce catalase and thus gives negative result with the test).

The test involves treating a day old bacterial culture with Hydroxygen peroxide (3%), if catalase is present, Hydrogen peroxide is cleaved into water and oxygen, which is observed as production of bubbles. This inference is taken as postive result. Since staphylococcus is having catalase, it answers the test

ii. Coagulase test: Used to differentiate Staphylococcus species which are having coagulase or clumping factor, from species which are devoid of it. Agglutination indicates the positive result. Since Staphylococcus sciuri, does not have coagulase, it gives negative result to this test.

iii. Oxidase test: This test is used to detect the presence of cytochrome c oxidase in the organism, if present it reacts with tetramethyl para phenylenediamine, whose oxidation will result in purple color. This is taken as positive inference. As Staphylococcus sciuri is having cytochrome c oxidase, it gives positive result.

The scheme of tests that helps in drawing conclusions for identification of different gram positive bacteria is described in the following figure:

2) a) A normally sterile site:

Findings in Blood: Gram-positive cocci like staphylococci, streptococci, diplococci like streptococcus pneumonia , Gram positive bacilli like clostridium, Listeria or diphtheriods

Findings in Joint aspirate: Gram-positive cocci like staphylococci, streptococci

2) b) A non-sterile site:

Findings in wound swab: Gram-positive cocci like staphylococci, streptococci, Gram positive bacilli like clostridium, Listeria or diphtheriods

Findings in throat swab: Gram-positive cocci like staphylococci, streptococci, gram positive oval forms with hyphae(yeasts)

Significance of the findings: Staphylococcal infections may lead to boils, food poisoning, impetigo, toxic shock.

Streptococci infections may represent sore throat, fever, low blood pressure, tissue damage, infections to the blood and other major organs

Lactobacilli and other diphtheriods in throat swab are not clinically significant in most of the cases

Clostridium species signify the presence of food poisoning, tetanus, Listeria presence denotes listeria infection with symptoms like flu, diphtheroids are common findings in throat, mouth and pharynx


Related Solutions

Thought and comments about this article MRSA which is a gram positive bacterium and is concerned...
Thought and comments about this article MRSA which is a gram positive bacterium and is concerned with skin and soft tissue infections, is one of the causes of community and hospital acquired serious infections. Community acquired MRSA (CA-MRSA) are distinct from hospital strains, infects and arises in young people of a community, those who are generally healthy and their healthcare do not receive in the hospital or on outpatient basis. Pimples and boils are the examples in this infection. On...
Thought and comments about this article MRSA which is a gram positive bacterium and is concerned...
Thought and comments about this article MRSA which is a gram positive bacterium and is concerned with skin and soft tissue infections, is one of the causes of community and hospital acquired serious infections. Community acquired MRSA (CA-MRSA) are distinct from hospital strains, infects and arises in young people of a community, those who are generally healthy and their healthcare do not receive in the hospital or on outpatient basis. Pimples and boils are the examples in this infection. On...
Staphylococcus aureus would have which of the following lab test results: a) alpha hemolytic, catalase positive,...
Staphylococcus aureus would have which of the following lab test results: a) alpha hemolytic, catalase positive, coagulase positive b) beta hemolytic, catalase positive, coagulase positive c) beta hemolytic catalase negative, coagulase negative d) beta hemolytic catalase positive, coagulase negative
OUTLINE the differences in the envelope structures of Gram-positive and Gram-negative bacteria. You may use diagrams...
OUTLINE the differences in the envelope structures of Gram-positive and Gram-negative bacteria. You may use diagrams or a table. Describe the behavior of chemotaxis in bacteria. Make sure to mention how the flagella contributes and how they can move toward good things and away from bad things. DESCRIBE the Endosymbiotic Theory and OUTLINE the evidence to support
A bacterium isolated from sewage sludge was recently found to be capable of anoxygenic photosynthesis using...
A bacterium isolated from sewage sludge was recently found to be capable of anoxygenic photosynthesis using nitrite as the electron donor, converting it to nitrate. Compare this form of nitrification to that which is well characterized. By removing nitrite from the environment, what other processes within the nitrogen cycle might this bacterium be influencing?
11.(3 pts) Consider what would happen to a gram-positive bacterium that could no longer link glucose...
11.(3 pts) Consider what would happen to a gram-positive bacterium that could no longer link glucose monomers together to form insoluble glycogen granules. Draw an “X” on the line next to the each of your predicted outcome(s) for the cell. ______ The osmotic pressure will increase inside the cell, cause it to lyse ______ The cell will be more susceptible to periods of carbon starvation ______ The cell will grow at a faster rate using the free glucose monomers Explain...
Description of biochemical tests for gram positive cocci chart micrococcus luteus micrococcus roseus staphlyococcus aureus staphlyococcus...
Description of biochemical tests for gram positive cocci chart micrococcus luteus micrococcus roseus staphlyococcus aureus staphlyococcus epidermidis streptococcus faecalis streptococcus thermophilus streptococcus pneumoniae
Which of the following is not true of the Gram-positive envelope?
Which of the following is not true of the Gram-positive envelope? Select one:  A. Has teichoic in its glycocalyx B. Has small periplasmic space C. Has thick peptidoglycan wall D. Has lipopolysaccharide in its glycocalyx
1.            Unknown bacteria #1 Gram-positive cocci Smooth, yellow colonies Growth, but not clearing or change on...
1.            Unknown bacteria #1 Gram-positive cocci Smooth, yellow colonies Growth, but not clearing or change on blood agar Positive for urease production Positive for gelatinase production Bubbling produced when exposed to H2O2 Name: ___________________________________ 2.            Unknown bacteria #2 Gram-positive cocci (mainly diplococci and chains) Encapsulated Produces green halo around growth on blood agar No color change with oxidase reagent No color change in urea broth Produces a yellow color in glucose, lactose, and sucrose phenol red tubes Name: ___________________________________ 3.           ...
The synthesis of an unknown compound (later confirmed to be 4-chlorobenzoic acid) must be isolated using...
The synthesis of an unknown compound (later confirmed to be 4-chlorobenzoic acid) must be isolated using acid-base extraction using the base NaOH. Write the the complete balanced eqn. C7H5ClO2 (aq) + NaOH (aq) = C7H4ClO2-Na+ (aq) + H2O This is my guess.... As well, do you start with 4-chlorobenzoic acid or 4-chlorobenzaldehyde if the eqn is correct.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT