Streptobacillus

Streptobacillus

Streptobacilli under a microscope

Streptobacillus is a genus of Gram-negative bacteria that are known for their characteristic chain-like formation. These bacteria are facultatively anaerobic and are commonly found in the upper respiratory tract of rodents. Streptobacillus is of particular interest in medical microbiology due to its role in causing rat-bite fever in humans.

Morphology

Streptobacilli are rod-shaped bacteria that typically form chains. They are non-motile and do not form spores. The cells are usually 0.5 to 0.8 micrometers in diameter and 2 to 5 micrometers in length. The cell wall of Streptobacillus is thin, characteristic of Gram-negative bacteria, and contains a lipopolysaccharide layer.

Pathogenicity

Close-up of Streptobacillus morphology

Streptobacillus moniliformis is the most well-known species within this genus and is the causative agent of rat-bite fever. This zoonotic infection is transmitted to humans through bites or scratches from infected rodents, or through the ingestion of contaminated food or water. Symptoms of rat-bite fever include fever, rash, and arthritis, and if left untreated, the disease can be fatal.

Diagnosis

Diagnosis of infections caused by Streptobacillus involves culturing the bacteria from blood or synovial fluid samples. The bacteria can be identified by their characteristic chain formation and biochemical tests. Molecular methods such as polymerase chain reaction (PCR) can also be used for more rapid and accurate identification.

Treatment

Infections caused by Streptobacillus are typically treated with antibiotics. Penicillin is the drug of choice, but other antibiotics such as doxycycline or tetracycline may also be effective. Early diagnosis and treatment are crucial to prevent complications.

Prevention

Preventive measures include avoiding contact with rodents and maintaining good hygiene practices. In laboratory settings, proper handling and disposal of rodent specimens are essential to prevent transmission.

Related pages

• Gram-negative bacteria
• Rat-bite fever
• Zoonosis
• Antibiotic treatment