In April, a preschool reports an outbreak among the children of a disease characterized by a high-grade (38.8°C to 40°C) fever that starts suddenly and rapidly falls. The children develop a short-lived (1 to 2 days) maculopapular rash that begins on the trunk and spreads to the extremities; the face is spared. The children have mild malaise, but otherwise do not appear ill. The most likely causative agent is
In August, you are called to a rural nursing home where several of the residents have developed a gastrointestinal disease consisting of fever, vomiting, and bloody stool. Lab analysis of the stool shows the presence of PMNs and Gram-negative rods. Epidemiological discussions with the residents indicate they all shared the same raw milk brought to one resident by his farmer son. The most likely cause of the infection is:
In February a 5-month-old girl is seen by her family physician. Her mother noted that she has been coughing and has had a slight fever for 3 days and recently developed difficulty breathing that is characterized by wheezing. She has a runny nose composed of clear fluid with some cells present. X-rays show her lungs are clear of infection. Examination of the nasal discharge is likely to show what entity to confirm diagnosis?
In February, a 75-year-old woman is brought to the hospital emergency department by her husband, who states that she had complained of a fever and headache during the past week. During the last 2 days, she has been confused and cannot perform her daily chores. Her physical examination indicates some weaknesses in her left side and her head MRI shows necrosis in the right temporal lobe. What is the most likely causative agent?
In the following pairs of organisms, which two are easiest to distinguish from each other by Gram stain?
In the laboratory, when a dense mixture of the patient’s isolate and plasma is placed on a slide, clumping is observed. This test is indicative of which initial step in the development of acute endocarditis in a healthy heart?
In which media is it best to isolate bacteria that can grow in a high salt concentration?
In any case, a clue indicating that the causative organism is an obligate intracellular pathogen transmitted by an arthropod bite should lead you to which of the following groups of organisms?
IgA is primarily responsible for safeguarding the respiratory and intestinal mucosal tract. The effectiveness of this protection relies on the function of a secretory piece, which is dependent on the age of the individual.
In a low-frequency recombination (Hfr) cross with an F2 bacterial cell, each having a single DNA molecule, what is the most probable result?