Question

A 35-year old male was transferred to the city via helicopter. The patient was in a multisystem failure that was brought on due to pneumonia. The patient went to his primary physician 5 days ago with the complaint of fever, fatigue, and vague respiratory symptoms. The physician suspected the patient had the flu and gave him some antibiotics. The patient’s condition became progressively worse and he developed shortness of breath with nausea and spiked a temperature.

The patient was admitted to the hospital where his symptoms worsened and so was transferred. In the city, physicians performed a bronchoscopic examination that revealed a mildly inflamed airway containing thin, watery secretions. A bronchial washing was obtained and sent to the laboratory for cultures.

Gram stain of bronchial washings culture:

            Few white blood cells seen.

            No epithelial cells seen.

            Few gram negative rods

The gram negative rods were not staining the best and so the lead microbiologist decided to also set the specimen to a Buffered Charcoal Yeast Extract agar (BCYE).

Bronchial Washing culture after 24 hour incubation:

            No growth

Bronchial Washing culture after 3 days of incubation:

            Gram negative rods, narrow on BCYE

Question:

a. Based on the growth and Gram stain characteristics, what organism should the technologist suspect in this patient? Explain your rationale for your response.

Question:

b. What ingredient in BCYE agar will allow the growth and presumptive identification of this organism?

Question:

c. What laboratory tests are available that may be able to give a rapid, preliminary diagnosis? There are three.

Question:

d. How is the organism acquired? How was this organism first (historically) identified?

Answer 1

Q.A)

Ans:  Based on the growth and gram stain characteristics, the organism isolated in bronchial secretions by the techonologist suspects lagionella, as the gram stain characteristics of patient bronchial secretions and characteristics of this bacteria looks similar that is, they are gram negative , the shape is rod shaped. these bacteria can grow at temperature  between 68–107.6°F, they cannot be grown well on ordinary medias, they generally grow on a Buffered Charcoal Yeast Extract agar as techonologist also suggested, and also it occasionally cause of pneumonia.

Q.B)

Ans: The ingredients used in BCYE agar to allow growth and identification of this organism is L-cysteine, α-ketoglutarate and ferric ions, where pH adjusted to 6.9. Some species of lagionella grows poorly on BYCE but they can be isolated by cultivation with amebae.

Q.C)

Ans: laboratory tests includes:

• CULTURE
• PCR
• ELISA