Strong urease production allows this organism to survive in acidic environments and give a rapid pink-colored test result in the lab.

Case Study 1: This 19-year-old student was in his usual state of health until the evening prior to admission, when he went to bed with a headache. He told his mother that he felt feverish, and on the following morning his mother found him in bed, moaning and lethargic. He was brought to the emergency room, where he appeared toxic and drowsy, but oriented. His temperature was 40C, his heart rate was 126/min., and his blood pressure was 100/60 mm Hg. He had an impressive purpuric rash (bruise-like), not blanching, most prominent on his trunk, legs and wrists. A gram stain of the material taken from one of the patient’s skin lesions showed gram-negative diplococci. His white blood cell count was 26,000/ml (high) with 25% band forms (high). The platelet count was 80,000/ml (low). Blood cultures were obtained and the patient was begun on intravenous Ceftriaxone. Blood cultures subsequently grew the organism seen on the gram stains of the lesions. Case Study 1 Question 1:  What is the most likely diagnosis for this patient?

Within 5 hours of returning home from lunch at your favorite all-you-can-eat buffet restaurant you feel very sick and are vomiting. The most likely cause is:

Case Study 3: A 3-year old girl presents at the emergency room with bloody diarrhea, fever and vomiting. The child’s mother reports that the day-care center called yesterday morning because she started having a watery diffuse diarrhea.  That night she began to complain of severe cramps and her diarrhea became bloody and pus-filled.  The family has no recent travel history and while they are vegetarians, they only consume pasteurized milk, cheese, and egg products.  The gram stain showed many white blood cells and many gram-negative bacilli.  The culture resulted in many colorless colonies on the MacConkey’s agar that were oxidase negative and fermented glucose. She was admitted to the hospital to treat her dehydration and for observation.  Case Study 3 Question 1: What was the most likely etiologic agent of infection in this patient? 

Case Study 2:  This 63-year-old alcoholic was taken to the emergency room of an outside hospital with obvious gangrene of both feet.  He was stuporous.  During that evening, he had a seizure and was treated with phenytoin and barbiturates.  By the night of transfer he was noted to have opisthotonic posturing and to have developed increasing respiratory distress and unresponsiveness.  On examination, he had a temperature of 41.7°C rectally, a blood pressure of 70/30 mmHg, a heart rate of 110 beats/min, and a respiratory rate of 40/min.  Examination was notable for marked trismus.  The neck was stiff and hyperextended.  Necrotic, blackened areas were present over both feet and several draining ulcers were noted on the heels and toes.  Neurologically the patient responded to deep pain with a grimace.  On the basis of these findings, specific therapy, in addition to supportive care, was initiated, and the patient ultimately recovered. Case Study 2.3:  What was the specific therapy used to treat this secondary infection?

Case Study 4:   An 8-year-old female was brought to the walk-in clinic by her mother. For the last three days she has been complaining that her ear has been bothering her and last night she developed a low fever.  Her vaccinations are all up to date, her medical history is unremarkable, and she has had no previous illness; she is a healthy girl. Her mother mentions that she is very active in sports, alternating between swimming and soccer competitions every weekend. The physician collected a culture and stat gram stain of the outer ear canal. The gram stain showed many white blood cells and gram-negative bacilli.  The physician then gave the girl antibiotic drops to use twice a day for seven days without waiting for the culture results. Case Study 4 Question 1:  What infection does the little girl have?

Explain how Clostridium botulinum and Clostridium tetani virulence factors exert their effect on muscle action. Be sure to relate this to the action of acetylcholine.

Which organism is the MOST COMMON cause of food-borne bacterial gastroenteritis in the US is:

Case Study 4:   An 8-year-old female was brought to the walk-in clinic by her mother. For the last three days she has been complaining that her ear has been bothering her and last night she developed a low fever.  Her vaccinations are all up to date, her medical history is unremarkable, and she has had no previous illness; she is a healthy girl. Her mother mentions that she is very active in sports, alternating between swimming and soccer competitions every weekend. The physician collected a culture and stat gram stain of the outer ear canal. The gram stain showed many white blood cells and gram-negative bacilli.  The physician then gave the girl antibiotic drops to use twice a day for seven days without waiting for the culture results. Case Study 4 Question 4:  What could this patient have done to prevent contracting this illness?

Case Study 2:  This 63-year-old alcoholic was taken to the emergency room of an outside hospital with obvious gangrene of both feet.  He was stuporous.  During that evening, he had a seizure and was treated with phenytoin and barbiturates.  By the night of transfer he was noted to have opisthotonic posturing and to have developed increasing respiratory distress and unresponsiveness.  On examination, he had a temperature of 41.7°C rectally, a blood pressure of 70/30 mmHg, a heart rate of 110 beats/min, and a respiratory rate of 40/min.  Examination was notable for marked trismus.  The neck was stiff and hyperextended.  Necrotic, blackened areas were present over both feet and several draining ulcers were noted on the heels and toes.  Neurologically the patient responded to deep pain with a grimace.  On the basis of these findings, specific therapy, in addition to supportive care, was initiated, and the patient ultimately recovered. Case Study 2.4:  How might this secondary infection have been prevented?