Erosive polyarthritis caused by sepsis due to a novel species of Streptobacillus notomytis.

Rat-bite fever (RBF) is characterized by fever, rash and arthritis, mainly caused by Streptobacillus moniliformis. We present a case of inflammatory erosive polyarthritis with sepsis caused by Streptobacillus notomytis, a novel species isolated from S. moniliformis. A 67-year-old man presented with fever, purpura and peripheral arthritis. After blood cultures were performed, loxoprofen administration was initiated. Arthritis partially improved, but left first metatarsophalangeal (MTP) arthritis persisted. A gram-negative rod was detected in the blood culture, and meropenem administration was started that improved arthritis. Ultrasonography and computed tomography revealed bone erosion in the left first MTP joint, leading to the diagnosis of septic arthritis. 16S rRNA gene sequence analysis revealed that this strain was S. notomytis. Further questioning revealed the patient may have had contact with rats. It is essential to consider Streptobacillus infection in the differential diagnosis of erosive polyarthritis.

Streptobacillus felis, a member of the oropharynx microbiota of the Felidae, isolated from a tropical rusty-spotted cat.

Streptobacillus felis is a fastidious microorganism and a novel member of the potentially zoonotic bacteria causing rat bite fever. Since its description, this is the second isolation of S. felis in a diseased member of the Felidae. Interestingly, the strain from this study was isolated from a zoo held, rusty-spotted cat (Prionailurus rubiginosus), with pneumonia, thereby indicating a possible broader host range in feline species. A recent preliminary sampling of domestic cats (Felis silvestris forma catus) revealed that this microorganism is common in the oropharynx, suggesting that S. felis is a member of their normal microbiota. Due to unawareness, fastidiousness, antibiotic sensitivity and lack of diagnostics the role of S. felis as a cat and human pathogen might be under-reported as with other Streptobacillus infections. More studies are necessary to elucidate the role of S. felis in domestic cats and other Felidae in order to better estimate its zoonotic potential.

Rat bite fever as a presenting illness in a patient with AIDS.

The etiology of culture-negative septic arthritis is poorly characterised in persons infected with human immunodeficiency virus (HIV). New molecular methods may assist in the investigation of culture-negative infections of sterile sites, including septic arthritis. We describe the first case of septic arthritis due to the cause of rat bite fever (RBF), Streptobacillus moniliformis, confirmed by 16S rRNA sequence analysis, in a patient with newly diagnosed HIV infection.

North American zoonoses.

A variety of infectious agents can be transmitted from animals to humans, either directly or indirectly. Unfortunately, the diagnosis of a zoonosis may not be considered at presentation, which can lead to a delay in initiating appropriate therapy, or is never made because the symptoms are non-specific and no exposure history is obtained. The keys to making a diagnosis are to recognize the clinical manifestations of the diseases (eg, fever of unknown origin, arthritis, rash, or lymphadenopathy), to obtain an exposure history, and to understand the local epidemiology. When a child presents with an unexplained febrile illness or infectious disease, clinicians should ask about potential exposures to animals, including pets, ingestion of unusual foods, such as raw or unpasteurized milk, and a travel history.

Dogs as vectors of Streptobacillus moniliformis infection?

Rat bite fever is a bacterial zoonosis transmitted through the bite of rats. One of the two etiological agents that cause rat bite fever is Streptobacillus moniliformis. Rat bite fever is rare and very likely under diagnosed but occurs worldwide. Other animals, like dogs and cats that have mouthed a rat are often mentioned in the literature as potential risks for the attraction of rat bite fever. However, rat bite fever caused by the bite of a dog or cat has very seldom been documented. Therefore, to identify the possible risk for humans to become infected with S. moniliformis after having been bitten by a dog that has been in contact with rats, the presence of S. moniliformis in the mouth of these dogs was tested with molecular methods. Swabs taken from the mouth of 18 dogs with proven contacts with rats were tested for the presence of S. moniliformis DNA by PCR. An amplicon of the right size was obtained in 10 of the 18 dogs. Nucleotide sequencing of five amplicons of PCR positive samples demonstrated the presence of S. moniliformis DNA in the mouth of three dogs. A bite by these dogs therefore might infect humans with S. moniliformis and cause rat bite disease.

Fatal rat-bite fever--Florida and Washington, 2003.

Rat-bite fever (RBF) is a rare, systemic illness caused by infection with Streptobacillus moniliformis. RBF has a case-fatality rate of 7%-10% among untreated patients. S. moniliformis is commonly found in the nasal and oropharyngeal flora of rats. Human infection can result from a bite or scratch from an infected or colonized rat, handling of an infected rat, or ingestion of food or water contaminated with infected rat excreta. An abrupt onset of fever, myalgias, arthralgias, vomiting, and headache typically occurs within 2-10 days of exposure and is usually followed by a maculopapular rash on the extremities. This report summarizes the clinical course and exposure history of two rapidly fatal cases of RBF identified by the CDC Unexplained Deaths and Critical Illnesses (UNEX) Project in 2003. These cases underscore the importance of 1) including RBF in the differential diagnoses of acutely ill patients with reported rat exposures and 2) preventing zoonotic infections among persons with occupational or recreational exposure to rats.