Page 41 - Review of Medical Microbiology and Immunology ( PDFDrive )

mebooksfree.com
mebooksfree.com
mebooksfree.com

mebooksfree.com
mebooksfree.com
mebooksfree.com
mebooksfree.com mebooksfree.com mebooksfree.com outside of the colon. The two most important members of the mebooksfree.com
mebooksfree.com
mebooksfree.com
PART I Basic Bacteriology
30
drug users. S. aureus is also present on the skin, but its main
colonic flora that cause disease are the anaerobe B. fragilis and
site is in the nose. It causes abscesses in the skin and in many
other organs.
the facultative E. coli. E. faecalis, a facultative, is also a very
important pathogen.
• Oropharynx. The main members of the normal flora of the
mouth and throat are the viridans streptococci, such as S.
isms in the vagina. They keep the pH of the vagina low, which
sanguinis and S. mutans. Viridans streptococci are the most
common cause of subacute endocarditis.
inhibits the growth of organisms such as C. albicans, an impor-
tant cause of vaginitis.
• Gastrointestinal tract. The stomach contains very few organ- • Vagina. Lactobacilli are the predominant normal flora organ-
mebooksfree.com
mebooksfree.com mebooksfree.com mebooksfree.com 4. An outbreak of postsurgical wound infections caused by S. mebooksfree.com
mebooksfree.com
• Urethra. The outer third of the urethra contains a mixture of
isms because of the low pH. The colon contains the largest
bacteria, primarily S. epidermidis. The female urethra can
number of normal flora and the most diverse species, includ-
become colonized with fecal flora such as E. coli, which predis-
ing both anaerobic and facultative bacteria. There are both
gram-positive and gram-negative rods and cocci. The members
poses to urinary tract infections.
of the colonic normal flora are an important cause of disease
SELF-ASSESSMENT QUESTIONS
aureus has occurred in the hospital. The infection control
1. The colon is the site of the largest number of normal flora
team was asked to determine whether the organism could be
bacteria. Which one of the following bacteria is found in the
carried by one of the operating room personnel. Using your
greatest number in the colon? (A) Colon
knowledge of normal flora, which one of the following body
mebooksfree.com
mebooksfree.com mebooksfree.com mebooksfree.com ANSWERS mebooksfree.com mebooksfree.com
sites is the most likely location for this organism?
(A) Bacteroides fragilis
(B) Clostridium perfringens
(C) Enterococcus faecalis
(B) Gingival crevice
(D) Escherichia coli
(C) Mouth
(E) Lactobacillus species
(D) Nose
2. A 76-year-old woman with a prosthetic (artificial) hip comes
(E) Throat
to you complaining of fever and pain in that joint. You are
concerned about an infection by S. epidermidis. Using your
knowledge of normal flora, what is the most likely source of
this organism?
(A) Dental plaque
2. (C)
(B) Mouth
3. (C)
(C) Skin
4. (D)
(D) Stomach 1. (A)
(E) Vagina
mebooksfree.com mebooksfree.com mebooksfree.com COURSE EXAMINATIONS mebooksfree.com mebooksfree.com
mebooksfree.com
3. Your patient is a 30-year-old woman with a previous history
PRACTICE QUESTIONS: USMLE &
of rheumatic fever who has had fever for the past 2 weeks.
On examination, you find a new heart murmur. You suspect
endocarditis and do a blood culture, which grows a viridans
Questions on the topics discussed in this chapter can be
group streptococcus later identified as S. sanguinis. Using
found in the Basic Bacteriology section of Part XIII:
your knowledge of normal flora, what is the most likely
USMLE (National Board) Practice Questions starting on
source of this organism?
page 709. Also see Part XIV: USMLE (National Board)
(A) Duodenum
Practice Examination starting on page 751.
(B) Skin
(C) Throat
(D) Urethra
(E) Vagina
mebooksfree.com mebooksfree.com mebooksfree.com mebooksfree.com mebooksfree.com mebooksfree.com

mebooksfree.com mebooksfree.com mebooksfree.com mebooksfree.com mebooksfree.com mebooksfree.com