What is the shape and arrangement of Streptobacillus moniliformis?
Morphology. Streptobacillus moniliformis is a highly pleomorphic, filamentous, gram-negative, nonmotile, and non-acid-fast rod. It usually appears straight but may be fusiform and may develop characteristic lateral bulbar swellings. The organism is typically arranged in chains and loosely tangled clumps (Fig.
What causes Streptobacillus moniliformis?
Streptobacillosis is a more common form of rat-bite fever, and it is also known as epidemic arthritic erythema. It is caused by Streptobacillus moniliformis and is transmitted by rat bite or ingestion of contaminated products usually milk (Haverhill fever).
Where is Streptobacillus found?
Streptobacillus moniliformis is commensal in wild rats, inhabiting the nasopharynx, middle ear, and respiratory tract. It is present in blood and urine of infected rats and is transmitted to humans by bite wounds, aerosols, and fomites (Will, 1994). The organism is nonpathogenic in rats.
What causes Streptobacillus?
Rat-bite fever (RBF) is an infectious disease caused by two different bacteria: Streptobacillus moniliformis, the only reported bacteria that causes RBF in North America (streptobacillary RBF) Spirillum minus, common in Asia (spirillary RBF, also known as sodoku)
What is the shape of Streptobacillus?
Streptobacillus moniliformis is a non-motile, Gram-negative rod-shaped bacterium that is a member of the family Leptotrichiaceae.
What kind of colonies do Streptobacillus form?
MACROSCOPIC APPEARANCE. Colonies are small, circular, convex, grayish, smooth, and, glistening. Streptobacillus sometimes exhibits a “fried egg” appearance with a dense center that penetrates agar. Colonies on serum agar are 1-2mm in three days.
Is Streptobacillus motile?
Is Streptobacillus multicellular?
The organisms are found in the throat and nasopharynx of wild and laboratory rats, and they may cause rat-bite fever in humans. It contains a single species, S. multifor´mis.
Is Streptobacillus harmful?
Less commonly the infection can cause pneumonitis, endocarditis or meningitis. As these symptoms are common to many febrile diseases, this is often classified as a fever of unknown origin (FUO). If untreated, death will occur in approximately 10% of cases.
Is Streptobacillus a spore former?
Spores: None. Other: Fastidious slow-growing organism (asporogenous).
What is cellular arrangement?
While arrangement refers to the groupings of individual cells, morphology describes the appearance of groups of bacteria, or colonies. Colony shapes can be round, irregular, filamentous or curled. Colonies might be flat or have a rounded elevation.
What is Streptobacillus in microbiology?
: any of a genus (Streptobacillus) of nonmotile gram-negative rod-shaped bacteria in which the individual cells are often joined in a chain especially : one (S. moniliformis) that is the causative agent of one form of rat-bite fever.
Can a rat get Streptobacillus moniliformis L form?
Although S. moniliformis is believed to be part of the commensal bacteria of the respiratory tract of rats, rats have occasionally shown signs of the disease. Antibiotics used to treat infection may cause the formation of the L-form, which persists in the body although this form is not pathogenic.
Is the Streptobacillus a rod-shaped bacterium?
Streptobacillus moniliformis. Streptobacillus moniliformis is a non-motile, Gram-negative rod-shaped bacterium that is a member of the family Leptotrichiaceae.
What kind of cultures are used for Streptobacillus moniliformis growth?
Trypticase soy agar or broth containing 10-20% blood, serum, or ascites fluid, as well as anaerobic culture bottles and resin bead culture systems can be used for growth because sodium polyanethol sulfonate is not normally present.
Is the bacillary type of moniliformis pathogenic?
The bacillary type is pathogenic. In contrast, the spontaneously occurring L form, which lacks a cell wall and whose colonies grow in a “fried egg” formation, is non-pathogenic. S. moniliformis has frequently been observed in the form of filamentous, non-branching chains and is highly pleomorphic.