**Klebsiella granulomatis** is a gram-negative bacterium belonging to the family Enterobacteriaceae. Here's a detailed look at its microbiological characteristics:
### Morphology
- **Shape**: *K. granulomatis* is rod-shaped (bacillus).
- **Size**: It typically measures about 1-2 micrometers in length.
- **Gram Stain**: It is gram-negative, meaning it does not retain the crystal violet stain used in the Gram staining procedure but takes up the counterstain (safranin or fuchsine), appearing pink or red.
### Cellular Characteristics
- **Intracellular Location**: *K. granulomatis* is an intracellular pathogen, meaning it primarily resides and multiplies within host cells.
- **Capsule**: The bacterium possesses a polysaccharide capsule, which helps it evade the host's immune response.
### Growth and Culture
- **Aerobic/Anaerobic**: It is facultatively anaerobic, meaning it can grow in both the presence and absence of oxygen.
- **Nutritional Requirements**: *K. granulomatis* has specific nutritional needs and is often challenging to culture in a laboratory setting. It requires enriched media for optimal growth.
### Pathogenesis
- **Tissue Invasion**: The bacterium invades the epithelial cells of the genital mucosa, leading to the formation of characteristic ulcerative lesions.
- **Granuloma Formation**: The infection results in granulomatous inflammation, characterized by the presence of macrophages, lymphocytes, and plasma cells.
- **Donovan Bodies**: In infected tissues, *K. granulomatis* can be identified within macrophages as Donovan bodies, which are intracellular inclusions containing the bacteria.
### Genetic and Biochemical Properties
- **Genome**: The genome of *K. granulomatis* is similar to other species within the Klebsiella genus but has specific adaptations for intracellular survival.
- **Biochemical Activity**: The bacterium exhibits typical biochemical reactions of the Klebsiella genus, such as lactose fermentation, but specific tests are needed to differentiate it from other Klebsiella species.
### Identification and Diagnosis
- **Microscopy**: The presence of Donovan bodies in stained tissue smears or biopsies is a key diagnostic feature.
- **Molecular Methods**: Polymerase chain reaction (PCR) and other molecular techniques can be used for more accurate identification and differentiation from other pathogens.
Understanding the microbiology of *Klebsiella granulomatis* is crucial for diagnosing and treating infections it causes, as well as for developing strategies to prevent its transmission.
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**C. granulomatis**, or *Klebsiella granulomatis* (formerly *Calymmatobacterium granulomatis*), is a gram-negative, intracellular bacterium that causes the sexually transmitted infection known as granuloma inguinale, or donovanosis.
This infection is characterized by the formation of ulcerative genital lesions.
Key features of *Klebsiella granulomatis*:
1. **Pathogenesis**: The bacterium invades and destroys tissue, leading to granulomatous ulcers primarily in the genital and perineal regions.
2. **Transmission**: It is primarily transmitted through sexual contact, but non-sexual transmission is also possible.
3. **Symptoms**: Early symptoms include the appearance of painless, beefy-red nodules on the genitalia or perineum, which eventually ulcerate and spread. If left untreated, the ulcers can cause significant tissue destruction and scarring.
4. **Diagnosis**: Diagnosis is typically made through clinical examination and confirmed by identifying Donovan bodies (intracellular inclusions of the bacterium) in tissue smears or biopsies stained with Wright-Giemsa stain.
5. **Treatment**: Effective treatment usually involves antibiotics, such as azithromycin, doxycycline, or trimethoprim-sulfamethoxazole.