A65 year-old man presents to the hospital with a one week history of malaise, headache, fever, and chills. he is admitted and over the next week his disease progressed with a worsening cough and shortness of breath. his physical exam was benign except for pulmonary compromise. a chest radiograph showed multilobar infiltrates. other significant laboratory findings include an elevated white blood cell count with increased neutrophils. because the patient had a prior history of drug abuse and alcoholism, a toxicology screen and hiv serology were performed. both were negative. a bronchoscopy was performed, with a bronchoalveolar lavage (bal) showing many white blood cells, but no organisms. calcofluor white stains for fungi and direct fluorescent-antibody stain (dfa) for pneumocystis were also negative. routine bacterial culture of the bal was negative.
why was the bal routine bacterial culture negative?
a. the patient's condition is not due to a microorganism
b. the pathogen is not a bacterium
c. the pathogen is not present in bal
d. routine bacterial culture was not sufficient to recover the pathogen
based on the patient’s history and conditio, what testing should be performer next?
a. nasopharyngeal culture for pertussis
b. bal culture for legionella
c. csf culture for h, influenzae
d. bone marrow culture for brucella
an organism was recovered only on buffered charcoal yeast extract agar. based on this information, what is the most likely pathogen?
a. b. pertussis
b. l. pneumophila
c. h. influenzae
d. brucella sp.
the organism was most likely trasmitted by:
a. handling of animal products
b. respiratory droplets from an infected person
c. inhalation of water droplets
d. an arthropod vector (e. g., tick)

what other testing can be performer to detect this organism in a patient?
a. urinary antygen testing
b. elek toxin testing
c. culture supplementation with cysteinę
d. urea breath test