Age/sex: unknown
Size: 18.5 x 8.5 x 4.6 cm
The kidney has been cut in its mid-portion and the two halves folded back to show multiple foci of necrotic (dead) tissue (N). Its appearance resembles cheese such as feta or camembert and is called caseous necrosis (from the Latin caseus – cheese). Such necrosis is characteristic of tuberculosis.
Renal tuberculosis
After the lungs, pleura and lymph nodes, the genitourinary tract is the most common site of tuberculosis. The kidney, epididymis (in men), and Fallopian tube (in women, see Specimen 23) are most frequently affected. The infection is believed to develop by blood borne seeding of Mycobacteria during primary pulmonary infection. Renal disease can present with symptoms such as pain on urination and blood in the urine. Epidydimal disease often presents as a tumor and Fallopian tube involvement as infertility.
Robert Koch (1843 – 1910) is regarded as one of the founders of modern bacteriology. He elucidated the nature of anthrax in 1876 and published evidence that a bacterium was the cause of tuberculosis in 1882. Two years later, he published his famous postulates necessary to establish a link between an infectious organism and disease:
1. The microorganism must be found in abundance in all organisms suffering from the disease and not in healthy organisms.
2. The microorganism must be able to be isolated from a diseased organism and grown in pure culture.
3. The cultured microorganism should cause disease when introduced into a healthy organism.
4. The microorganism must be re-isolated from the experimental host and identified as being identical to the original specific causative agent.
Although exceptions have been found to these rules, they provided a framework for the investigation of many infectious diseases in the early 20th century. Koch received the Nobel prize in 1905.
Below: Robert Koch.
Source: ZEISS Microscopy. (2015). Robert Koch. Wikimedia Commons. https:// commons.wikimedia.org/wiki/File:Robert_Koch_(6909161361).jpg
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