Block EXAM Flashcards
Three months ago, a 53-year-old woman had surgery and chemotherapy for breast cancer. Four weeks ago, she developed a cough occasionally productive of purulent sputum. About 2 weeks ago, she noted a slight but progressive weakness of her left arm and leg. On chest examination, rales were heard over the left upper back when the patient breathed deeply. Neurologic examination confirmed weakness of the left arm and leg. Chest radiography showed a left upper lobe infiltrate. Contrast-enhanced computed tomography showed two lesions in the right hemisphere. Gram stain of a purulent sputum specimen showed branching gram-positive rods that were partially acid fast. Cause of this patient’s current illness.
Nocardia farcinica
The drug of choice to treat this patient’s infection is
Trimethoprim-sulfamethoxazole
It is particularly difficult to differentiate Erysipelothrix rhusiopathiae from
Lactobacillus species
Movement of Listeria monocytogenes inside of host cells is caused by
Inducing host cell actin polymerization
An 8-year-old, who recently arrived in the United States, develops a severe sore throat. On examination, a gravish exudate (pseudomembrane) is seen over the tonsils and pharynx. The differential diagnosis of severe pharyngitis such as this includes group A streptococcal infection, Epstein-Barr virus (EBV) infection, Neisseria gonorrhoeae pharyngitis, and diphtheria. The cause of the boy’s pharyngitis is most likely:
A club-shaped gram-positive bacillus
The primary mechanism in the pathogenesis of the boy’s disease
Inactivation of elongation factor 2
Corynebacterium jeikeium is
Often multidrug resistant
Which of the following aerobic gram-positive bacilli is modified acid-fast postive?
Nocardia brasiliensis
Skin diphtheria as occurs in children in tropical areas typically
Results in protective antitoxin levels in most children by the time they are 6-8 years old
A 45-year-old fiaherman imbedded a fishhook into his right forefinger. He removed it and did not seek immediate medical therapy. Five days later, he noted fever, severe pain, and nodular-type swelling of the finger. He sought medical therapy. The violaceous nodule was aspirated, and after 48 hours of incubation, colonies of a gram-positive bacillus that caused greenish discoloration of the agar and formed long filaments in the broth culture were noted. The most likely cause of this infection is
Erysipelothrix rhusiopathiae
A biochemical reaction that is useful in the identification of the causative agent of the infection is
Production of H2S
Listeria monocytogenes is frequently a foodborne pathogen because
It can survive at 4°C
It can survives under conditions of low pH
It survives in the presence of high salt concentrations
After recovery on laboratory media, the aerobic Actinomycetes are best identified by
Molecular methods such as 16SrRNA gene sequencing
Which of the following statements regarding Rhodococcus equi is correct?
It is a rare cause of pulmonary infection in humans
A hospitalized patient who had an indwelling urinary catheter develops fever, chills, suprapubic pain, and difficulty voiding 48 hours after the catheter is removed. His bladder appears obstructed, and he has white blood cells and bacteria on a urinalysis. Cystoscopy reveals a large bladder stone, and the urine culture grows greater than 10,000 CFU/mL of a short, irregular gram-postive rod. The most likely organism causing this infection is
Corynebacterium urealyticum
