Author: Brian Holtry

Secondary Syphilis

The secondary stage of syphilis occasionally overlaps with the primary phase but usually begins ~ 6 weeks after resolution of the chancre; however, it can develop as late as 6 months after infection (see Box  1). Most patients have some degree of skin or mucocutaneous involvement. A faint and evanescent macular rash of the trunk and abdomen known as roseola syphilitica is sometimes seen initially.

Primary Syphilis

The lesions of primary syphilis appear at the site of inoculation after an incubation period that is inversely proportional to the number of infecting organisms, usually 3 weeks (Box 1). The chancre is an ulcerative lesion that varies in size from several millimeters to 2 cm.

Actinomycetes

Originally thought to be fungi due to their hyphae-like appearance, they are now recognized as bacteria based on their cell wall components, reproduction by fission without sporulation or budding, inhibition by antibacterial agents, and molecular phylogenetic analysis. The actinomycete chromosomes contain a high content of guanosine and cytosine.

Actinomyces

Disease occurs when mechanical insult disrupts the mucosal barrier or organisms gain access to privileged sites. For example, actinomycosis commonly occurs after dental procedures, trauma, surgery, or aspiration. Actinomyces israelii causes the majority of human disease owing to this genus, but other species, including Actinomyces naeslundii, Actinomyces viscosus, Actinomyces enksonii, Actinomyces odontolyticus, and Actinomyces meyeri have also been implicated. Actinomycosis is threefold more common in men than women.

Nocardia

Nocardia spp. are strictly aerobic, ubiquitous soil-dwelling organisms that are largely responsible for the decomposition of organic plant material. Infection usually occurs via inhalation of these organisms in airborne dust particles, leading to pulmonary disease.

Other Mycobacteria

The increasingly relative importance of the atypical mycobacteria, many of which are ubiquitous in the environment, was recognized with the decline in tuberculous disease. Generally, atypical mycobacteria are unusual causes of disease in patients who are immunocompetent but can in immunocompromised hosts such as AIDS and cancer patients.

Mycobacterium Leprae (Leprosy)

Although not a common problem in the United States, it is in other parts of the world. With the advent of effective antimicrobial agents, the number of cases of leprosy worldwide has fallen from 12 million in 1982 to 6 million in 1991. It remains a significant problem, however, because the incidence of new cases has not yet declined, and much of the affected population lives in areas where effective medical treatment is difficult to obtain.

Tuberculosis

Approximately one-third of the world’s population is infected with M tuberculosis, according to World Health Organization estimates, resulting in 2.9 million annual deaths. In the United States, tuberculosis is on the rise, after several decades of steady decline.