Exam 18: Microbial Pathogenesis

The figure below illustrates T.brucei inside a host.Explain what is happening in the figure.

Toxins made and secreted by bacterial cells are called ________ while toxins contained within the bacterial cell wall are called ________.

CASE HISTORY Will,a formerly rambunctious five-year-old from San Francisco,was taken to the emergency department after having a severe cough for two weeks.His illness started as a runny nose,dry cough,and low-grade fever.But within days the coughing would come in violent fits lasting up to one minute (called a paroxysm).The nurse practitioner attending Will observed one of these fits.Unable to breathe between coughs,the boy became cyanotic (turned blue).When the staccato of coughs finally ended,Will gasped,desperate for breath.The air rushing to fill his lungs made an ear-piercing whooping sound.This telltale "whoop" led the nurse practitioner to suspect whooping cough,a disease highly contagious in its early stages.In the later stages (greater than four weeks)the patient is no longer contagious because the bacterial agent,Bordetella pertussis,has succumbed to the immune response.However,the telltale cough will persist for weeks while the lungs repair the damage caused by the pertussis toxins.The nurse practitioner,now wearing a mask,took a nasopharyngeal swab sample for bacteriological culture and prescribed the antibiotic azithromycin (a member of the macrolide class of antibiotics that inhibit protein synthesis).Because the organism takes so long to grow in the laboratory (5-12 days)and because the organism is hard to find late in the disease,a blood sample was also drawn to test for anti-B.pertussis immunoglobulin a antibody.By the next day the serum test was positive for B.pertussis antibodies.The pathogen eventually also grew in the culture.Despite extensive efforts at vaccination,more than 41,000 cases of whooping cough were reported in the United States in 2012. Several of the protein exotoxins produced by Bordetella pertussis act by disrupting signal transduction.Which of the following exotoxin-target pairs is NOT properly matched?

Which of the following is true regarding type II secretion systems?

All of the following are required for disease to occur.What is the second step in microbial pathogenesis?

Interfering with microbial attachment results in

All of the following are true about bacterial capsules EXCEPT

Rickettsia will not grow outside a living eukaryotic cell.What type of organism is this?

Some microbes use tiny molecular syringes called ________ to inject proteins directly into the host cytoplasm.

The human immunodeficiency virus (HIV)primarily targets which subset of immune cells?

Shiga toxin polypeptide B binds to surface gangliosides on target cells.If the gangliosides were removed

The fimbriae of E.coli is an example of a(n)