Page 211 - Review of Medical Microbiology and Immunology ( PDFDrive )

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mebooksfree.com mebooksfree.com mebooksfree.com the flocculation of lipids (cardiolipin) extracted from nor- mebooksfree.com
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PART II Clinical Bacteriology
200
mal mammalian tissues (e.g., beef heart).
Both specific antitreponemal antibody and nonspecific
reagin are used in the serologic diagnosis of syphilis.

Transmission & Epidemiology

Treponema pallidum is transmitted from spirochete-
containing lesions of skin or mucous membranes (e.g.,
genitalia, mouth, and anus) of an infected person to other
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mebooksfree.com mebooksfree.com mebooksfree.com tious. Treponema pallidum is a human organism only. mebooksfree.com
persons by intimate contact. It can also be transmitted
from pregnant women to their fetuses. Rarely, blood for
transfusions collected during early syphilis is also infec-
There is no animal reservoir.
Syphilis occurs worldwide, and its incidence is increas-
ing. It is one of the leading notifiable diseases in the United
FIGURE 24–1
Treponema pallidum—dark field microscopy.
States. Many cases are believed to go unreported, which
The coiled form of this spirochete is in the center of the field. (Source:
limits public health efforts. There has been a marked
Dr. Schwartz, Centers for Disease Control and Prevention.)
with men in recent years.
Additional information regarding the clinical aspects of increase in incidence of the disease in men who have sex
Pathogenesis & Clinical Findings
infections caused by the organisms in this chapter is pro-
Important Properties mebooksfree.com
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Treponema pallidum produces no important toxins or
vided in Part IX entitled Infectious Diseases beginning on
enzymes. The organism often infects the endothelium of
page 593.
ing all stages of syphilis but is particularly important in the
TREPONEMA
pathogenesis of the brain and cardiovascular lesions seen in
tertiary syphilis.
1. Treponema pallidum
In primary syphilis, the spirochetes multiply at the site
Disease
of inoculation, and a local, nontender ulcer (chancre) usu-
ally forms in 2 to 10 weeks (Figure 24–2). The ulcer heals
Treponema pallidum causes syphilis.
Treponema pallidum has not been grown on bacteriologic
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administration of the antibiotic. mebooksfree.com
media or in cell culture. Nonpathogenic treponemes, which
are part of the normal flora of human mucous membranes,
can be cultured.
Treponema pallidum grows very slowly. The medical
importance of that fact is that antibiotics must be present at
an effective level for several weeks to kill the organisms and
cure the disease (see “Treatment” section later). For exam-
ple, benzathine penicillin is the form of penicillin used to
treat primary and secondary syphilis because the penicillin
is released very slowly from this depot preparation, and
bactericidal concentrations are present for weeks after

The antigens of T. pallidum induce specific antibodies, FIGURE 24–2
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mebooksfree.com mebooksfree.com mebooksfree.com ulcer with a rolled edge (red arrow) that is typical of a syphilitic chan- mebooksfree.com
which can be detected by immunofluorescence or hemag-
glutination tests in the clinical laboratory. They also induce
1
nonspecific antibodies (reagin), which can be detected by
Chancre of primary syphilis. Note the shallow
cre. (Reproduced with permission from Wolff K, Johnson R. Fitzpatrick’s Color Atlas &
1
Synopsis of Clinical Dermatology. 6th ed. New York: McGraw-Hill, 2009. Copyright ©
Syphilitic reagin (IgM and IgG) should not be confused with the reagin
(IgE) antibody involved in allergy.
2009 by The McGraw-Hill Companies, Inc.)

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