A patient comes to see you, complaining of a very sore throat. When you examine her, you find that she has a fever of 39-degree Celsius, and you observe that her throat is extremely red, with pus on her tonsils. You swab the pus and make a slide, which you then send to the clinical lab for Gram staining. The lab sends back a report in which it is noted that the slide has many long chains of round cells that have stained purple in color. you inform the patient that the result of the gram stain indicate to you that the bacteria in her throat are in shape, and have a cell wall

1) round; thin

2) cylindrical; thick

3) round; thick

4) spiral; thick

5) cylindrical; thin

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Hubert KochLv2

14 Dec 2018

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Related questions

A 47 year old female patient presents herself to you with symptoms of pneumonia. All indications are that the patient is suffering from an infection of Streptococcus pneumoniae, a Gram-positive bacterium. Since the patient is not allergic to penicillin, you prescribe a dose of amoxicillin, a semi-synthetic penicillin. This drug works by blocking the peptide cross-links, between the muramic acid subunits, of peptidoglycan chains. This leads to a destabilization of the bacterial cell, leading to its rupture.

However, after the patient finished her course of amoxicillin, no improvement in symptoms were reported. Perplexed, you decide to culture and examine the bacteria infecting her lungs. The test you order is a Gram stain test, which comes back as Gram-negative. You feel like a failure as a health care provider due to your misdiagnosis of this bacterium.

The same day, you put the patient on an aminoglycoside class antibiotic. This antibiotic is Gram-negative specific and works by shutting down ribosomes. You are dismayed and confused when this treatment also fails.

To get a full read on the disease, you have a barcoding DNA test done on the causative bacterium. The test comes back and it clearly shows that the bacterium is within the group of Gram-positive bacteria. With the results of this test, you come up with the theory that the patient is infected with a strain of Drug Resistant Streptococcus pneumoniae (DRSP), resistant to amoxicillin. You decide to treat the DRSP by administering intravenous vancomycin, which is indicated for the treatment of serious, life-threatening infections by Gram-positive bacteria. This treatment also fails.

In the end, you figure out that you were wrong about everything, and that there was a simple solution to the treatment of the patient.

Now knowing that the patient was infected with Mycoplasma pneumoniae, what is the likely explanation for the false Gram-negative test?

Before you answer this question you may want to know how Gram staining works. Briefly, the Gram stain is a differential stain meaning that you are using two dyes that stain different structures. Based on the structural differences of the bacteria, the dyes will interact differently with them, producing different results (colors). The Gram stain (Crystal Violet together with Gram's iodine) stains thick layers of peptidoglycan purple and thin layers of peptidoglycan very, very lightly purple. The second stain (or counterstain) is safranin. Safranin is a dye which interacts with and binds to lipid bilayers. Yes, safranin also stains the cytoplasmic membrane of Gram-positive bacteria, but the deep purple color of the Gram stain makes it impossible to see.

A.	The Gram stain was able to penetrate the cell making it turn pink
	B.	The counterstain stained the cytoplasmic membrane, making it look like a Gram-negative bacterium
	C.	The counterstain stained the mycolic acid in the cellular envelope, thus making it look like a Gram-negative bacterium
	D.	The Gram stain lightly stained the present peptidoglycan (making it look pink rather than red).

yellowspider532

Delia, a five-year-old, woke up one morning complaining that she had a sore throat, headache and stomachache. Her tonsils appeared swollen, and a tonsular exudate, appearing as a cream-colored pus, was evident upon examining the childâs oropharynx. Her mother also took Deliaâs temperature and noted the girl was running a low-grade fever. Suspecting strep throat (streptococcal pharyngitis), her mother made an appointment with the pediatrician.

The doctor first performed a rapid strep test, which works by detecting certain cell surface proteins on group A streptococci (GAS). This test is inexpensive and can detect GAS in a matter of minutes. However, rapid strep tests that come back negative are not especially reliable; about five out of every 100 patients with streptococcal pharyngitis will have a negative rapid strep test result. Therefore, despite Deliaâs rapid strep test being negative, the doctor went ahead and ordered a bacterial culture. This was a wise decision because Delia had signs and symptoms that pointed to a case of streptococcal pharyngitis caused by the Gram-positive, nonmotile, encapsulated prokaryote Streptococcus pyogenes.

When cultures to detect S. pyogenes are performed, the patientâs sample (in this case a swab of the throat) is streaked out onto a specialized nutrient-rich agar called blood agar. Actively growing S. pyogenes can break down red blood cells (a process called beta hemolysis), and, therefore, is readily detectable on blood agar plates because a clear zone develops around its colonies. Based on the microbiology data that came back, Delia was treated for streptococcal pharyngitis. After 48 hours on an antibiotic, Delia felt much better and returned to school.

QUESTION: Assuming that Delia is not allergic to penicillin-based drugs, would a penicillin-family drug (amoxicillin, for example) typically be effective against S. pyogenes?

A. Penicillin-based drugs would effectively target the thick peptidoglycan layer within the pathogenâs cell wall.

B. Penicillin-based drugs would be ineffective since the cell wall of S. pyogenes does not contain peptidoglycan.

The porins within the pathogenâs outer membrane would exclude penicillin-based drugs, rendering these antimicrobials C. ineffective.

D. Penicillin-based drugs would effectively target the mycolic acids present in the pathogenâs cell wall.

Case study

A patient has been admitted to your pediatric intensive care unit. He is a twelve-month-old male who was transferred to your institution with a six-day history of respiratory infection. Furthermore, the patient has not been moving or eating for the past day. Shortly before admission the parents noticed that the child was having difficulty breathing. On admission the patient had a fever and enlarged lymph nodes, but his lower respiratory tract was normal and appeared to be uninfected. The patient also had an inflamed pharynx, which was producing yellow pus. There was also a thick layer of yellowish-green material over the pharynx, which bled when the patientâs throat was swabbed. The swab was used to culture and Gram-stain the pus, which had a large amount of purple bacilli. His diet consisted primarily of breast milk, and occasionally honey. The patientâs medical history revealed that he had received no immunizations. The father had recently returned from Western Uganda where he had been performing anthropological research on local populations in the area. Both parents had visited various parts of Africa over the previous decade.

1) What disease does the child have, and how did you determine this? State the proper scientific name of the causative organism. What domain and kingdom does the responsible pathogen belong to? If it doesnât belong to a domain or kingdom, try to classify it as best you can. 2) What body system did the pathogen target, and how did the child contract the disease? What mechanism does the microbe you identified use to cause the disease? What route of entry did it use? 3) How would you treat this disease? Explain what each treatment involves in detail, and how it will help. 4) Is the disease communicable?