Case Study 1:  The patient was a 37-year-old male with hemop…

Case Study 1:  The patient was a 37-year-old male with hemophilia.  He was HIV positive and had progressed to full-blown AIDS in the past 3 months.  His current medications included factor VIII treatments, suppressive treatment with the antimicrobial agents trimethoprim/sulfamethoxazole, and azidothymidine (AZT).  He presented with a 3-day history of voluminous bloody diarrhea, 10-lb (ca. 4.5-kg) weight loss, and profound dehydration.  Tests for ova and parasites and culture for Salmonella, Shigella, Yersinia, and Campylobacter were negative three times.  He gave no recent travel history, nor had he recently consumed shellfish. Case Study 1.2:  What role do suppressive antimicrobial agents have in predisposing this patient to his current infection?

You have a set of plates from a urine culture, one SBAP and…

You have a set of plates from a urine culture, one SBAP and one MacConkey, both have greater than 100,000 colonies.  A gram stain indicates the presence of gram-negative bacilli.  You suspect it could either be from the Enterobacteriaceae family or is a Non-fermenter.   You have determined that the organism originated from the Enterobacteriaceae family.  How would you determine if the organism was pathogenic or nonpathogenic?  

Case Study 3: A 3-year old girl presents at the emergency ro…

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 yellowish-clear 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?