Infection, Infectious Diseases and Epidemiology – Part 1

True or false:  All human resident microbiota are non-pathogenic.

In a normal, health pregnancy, microbes that might be present in the bloodstream of the mother do not come into contact with that of the fetus. This is due to the presence of

Staphylococcus aureus is a common member of the nasal mucosa in many humans. Though it normally is not associated with illness, some strains can associated with scalded skin syndrome, toxic shock syndrome, pimples, boils, cellulitis and gastroenteritis. Which of the following terms best describe this phenomenon?

True or false: The human infant only begins to be infected by normal microbiota following birth?

The male urogenital tract is normally not associated with the same population of resident microbiota found in females. Which of the following is the most reasonable explanation for this?

Of the following groups, which are the most likely to be found in the vaginal mucosa of a healthy woman during her childbearing years?

In a normal, healthy human gastrointestinal tract, one would expect to find

The presence of microbes in the alveoli of the lungs

One of the most common organisms living on human skin is Staphylococcus epidermidis. Except in rare cases, this microbe is not associated with illness, but has no beneficial effect while living in the pores and hair follicles. What term best represents the relationship it has with the human body?

Escherichia coli in the human gastrointestinal tract synthesize and excrete vitamin B12 which is used by the host.  The large populations of such microbes, stimulated to grow by the constant supply of fresh food and water also prevent potential pathogen infection via competitive exclusion. Which of the following terms best describes this relationship?