Tags: Abdominal pain

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.

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 Avium Complex (Disseminated & Pulmonary Disease)

Mavium is the most common atypical mycobacterium to cause disease in humans. In immunocompetent patients, M avium can cause pulmonary disease (Box 1). It is the most common pulmonary pathogen of all the atypical mycobacteria. There are several risk factors for pulmonary M avium infection besides AIDS.

Brucella, Francisella, Pasteurella, Yersinia, & Hacek

Brucellosis (also called undulant fever, Mediterranean fever, Malta fever) is an infection that causes abortion in domestic animals. It is caused by one of six species of Brucella coccobacilli. It may occasionally be transmitted to humans, in whom the disease could be acute or chronic with ongoing fever and constitutional symptoms without localized findings.

Yersiniosis

Conditions that are associated with increased risk for Yersinia spp. infections (yersiniosis) include iron overload states (such as in patients who receive chronic blood transfusions or those with hemochromatosis) and the use of desferrioxamine, a bacterial siderophore. Infections caused by Y enterocolitica are more common in children than adults.

Legionella

More than 25 species and 48 serogroups of Legionella have been identified. Legionella pneumophila (especially serogroup 1) causes ~ 70-80% of cases of legionellosis, but L micdadei, L bozemanii, L dumoffi, L feelei, L longbeacheii, and other species are also pathogenic. The true incidence of legionellosis, which includes Legionnaires’ disease and Pontiac fever, is difficult to establish.

Legionella: Clinical Syndromes

Legionella species are associated with outbreaks of either Pontiac fever, a self-limited influenzalike condition in otherwise healthy people, or Legionnaires’ disease, a severe pneumonic disease more common among elderly and immunocompromised individuals.

Vibrio & Campylobacter

Cholera is a disease of antiquity and probably represents some of the diarrheal illnesses described by Hippocrates and other early physicians. Robert Koch discovered V cholerae in 1884. Since the 17th century, at least eight epidemics of cholera have swept the globe. At least seven of the eight pandemics originated from the Ganges River delta, where cholera is endemic.

Noncholera Gastroenteritis

Noncholera gastroenteritis is often associated with recent ingestion of raw or undercooked shellfish and often occurs in the summer or early fall in the United States. A typical presentation includes explosive diarrhea, low-grade fever and chills, and mild-to-moderate abdominal pain with cramping.