A medical technician is trying to isolate a pathogen from the sputum sample of a patient. The sample is heat fixed to a slide then covered with carbol fuchsin stain and heated again. After washing off the stain with clean water, the slide is covered with 1% sulfuric acid for decolorization. The sample is rinsed again and stained with methylene blue. Microscopic examination shows numerous red, branching filamentous organisms. Which of the following is the most likely isolated pathogen?
ACryptococcus neoformans
BTropheryma whipplei
CNocardia asteroides
DRickettsia rickettsii
EStaphylococcus aureus
An investigator is studying the growth of an organism in different media. The organism is inoculated on a petri dish that contains heated sheep blood, vancomycin, nystatin, trimethoprim, and colistin. The resulting growth medium is incubated at 37°C. Numerous small, white colonies are seen after incubation for 48 hours. This organism is most likely to cause which of the following conditions?
APontiac fever
BPseudomembranous colitis
CHemolytic uremic syndrome
DOral thrush
EGonorrhea
A 62-year-old woman with type 2 diabetes mellitus is brought to the emergency department by her husband because of fever, chills, and purulent drainage from a foot ulcer for 2 days. Her hemoglobin A1c was 15.4% 16 weeks ago. Physical examination shows a 2-cm ulcer on the plantar surface of the left foot with foul-smelling, purulent drainage and surrounding erythema. Culture of the abscess fluid grows several bacteria species, including gram-negative, anaerobic, non-spore-forming bacilli that are resistant to bile and aminoglycoside antibiotics. Which of the following is the most likely source of this genus of bacteria?
AStomach
BOropharynx
CVagina
DColon
ESkin
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