Rat bite fever mimicking ANCA-associated vasculitis.

Rat bite fever (RBF) is a rare infectious zoonotic disease caused by two bacterial species: the Gram-negative rod Streptobacillus moniliformis and the Gram-negative coiled rod Spirillum minus. The association between RBF and skin vasculitis and arthritis has been observed. The aim of this paper was to present a case of rat-bite fever with symptoms of skin vasculitis and arthritis, associated with high titers of ANCA antibodies and anti-endothelial cell antibodies suggestive of primary vasculitis. The patient was successfully treated with antibiotics and non-steroidal anti-inflammatory drugs, leading to significant improvement. Based on the presented case, we discuss the differential diagnosis of the signs and the role of infection in the induction of ANCA antibodies. We reviewed the English language literature for cases of RBF presenting with symptoms of vasculitis and/or antibody presence. A literature review was performed in PubMed and Google using the keywords "rat bite fever" AND "vasculitis", "systemic vasculitis", "ANCA", "antiendothelial antibodies". No cases of rat-bite fever with the presence of ANCA antibodies or AECA antibodies in its course have been described thus far. Rat bite fever is a rare disease with nonspecific symptoms. In its course, general weakness, intermittent fever, leukocytoclastic vasculitis, and arthritis are reported. To our knowledge, this is the first reported case of ANCA positivity associated with RBF.

Rat bite fever: a case report review.

CONTEXT: Rat bite fever is a rare disease with a challenging differential diagnosis. The zoonosis has a potentially lethal course in a vulnerable population (children and low socioeconomic class) and a commonly available standard therapy (penicillin). This case report review outlines common epidemiological and clinical factors to improve clinical awareness and timely response to therapeutic actions. METHODS: A systematic literature review was conducted in the PubMed database looking for English language European case reports of rat bite fever from 2000 to 2021. RESULTS: In 17 out of 20 selected cases, the condition of the index patient was identified as an infectious syndrome. Thanks to the almost omnisensitive susceptibility pattern of Streptobacillus moniliformis, timely antibiotic administration prevented an unfavorable outcome in all these cases. However, in the three remaining cases, the initial diagnoses were arthritis (on autoimmune basis and gout) and viral syndrome. Due to delayed antibiotic administration, one case suffered persistent harm, while the other two cases encountered prolonged illness. CONCLUSION AND RECOMMENDATIONS: Rat bite fever is a diagnosis that can be easily missed from both a clinical and a microbiological point of view. As such, rat bite fever becomes part of the differential diagnosis whenever a patient presents with a fever syndrome after being in contact with rodents. In the case of persistent fever, blood culture sampling should be performed even in the absence of a systemic inflammatory response. A bacterial 16S ribosomal RNA PCR on blood or joint aspiration (cultures) is an even more sensitive diagnostic test. Since most transmissions occurred in a domestic setting, keeping rats as pets cannot be recommended.

Rat Bite Fever: Variability in Clinical Presentation and Management in Children.

Rat bite fever is a systemic illness most commonly caused by Streptobacillus moniliformis that is classically characterized by fever, rash and migratory polyarthritis. Here, we highlight the highly variable clinical presentations of rat bite fever in children and the importance of maintaining a high degree of suspicion so appropriate treatment can be promptly initiated.

A real-time multiplex PCR assay for detection of the causative agents of rat bite fever, Streptobacillus moniliformis and zoonoticStreptobacillus species.

Rat bite fever (RBF) caused by Streptobacillus moniliformis has been described as a diagnostic challenge. While it has a favorable prognosis with treatment, timely diagnosis is hindered by the lack of culture-free identification methods. Here we present a multiplex real-time PCR assay that detects the zoonotic Streptobacillus spp. as well as differentiate the primary causative agent of RBF, Streptobacillus moniliformis. The performance of this assay was evaluated using mock clinical specimens for blood, serum, and urine. Analytical sensitivity was determined to be 3-4 genome equivalents (GE)/µl for the zoonotic Streptobacillus spp. target, and 1-2 GE/µl for the S. moniliformis specific target. The assay correctly detected only the intended targets with no cross-reactivity identified. The pathogen was detected in all spiked matrices and not detected in the negative non-spiked specimens. This rapid diagnostic assay may permit quicker diagnosis of RBF patients.

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 moniliformis With Features of Hemophagocytic Lymphohistiocytosis Identified by Direct Sequencing.

Rat-bite fever caused by Streptobacillus moniliformis is a rare infection that may be fatal. An adolescent male presented with multiorgan failure, negative blood cultures and Gram-negative rods in blood smear. S. moniliformis was identified by 16S ribosomal RNA gene sequencing from the blood. He developed systemic hyperinflammatory syndrome resembling hemophagocytic lymphohistiocytosis, for which immune-globulins and steroids were added to the antibiotic regimen and he rapidly recovered.

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.

Streptobacillus moniliformis bacteraemia: A case report / Bacteriemia por Streptobacillus moniliformis: a propósito de un caso

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Rat bite fever caused by Streptobacillus moniliformis infection in a Chinese patient.

BACKGROUND: Rat bite fever (RBF), a severe infectious disease, can result from transmission of the pathogen Streptobacillus moniliformis (S. moniliformis) by rat bite. RBF diagnosis can be overlooked. CASE PRESENTATION: We present a case of RBF in a Chinese patient who was infected with S. moniliformis in mainland China. Meta-next generation sequencing (mNGS) was used to identify potential pathogens and detected S. moniliformis genome sequences in the pustular sample in less than 72 h. Then the diagnosis was validated by polymerase chain reaction analysis. Despite having severe RBF with complications, this 54-year-old male patient was successfully cured with penicillin as a result of timely pathogen-based diagnosis. CONCLUSIONS: Physicians should inquire about recent rat exposure and consider the possibility of RBF when a patient develops unexplained fever and rashes. mNGS is a new diagnostic technology and may identify RBF pathogens even when blood culture results are negative.

Rat-Bite Fever in Human with Streptobacillus notomytis Infection, Japan.

We report a case of rat-bite fever in a 94-year-old woman with Streptobacillus notomytis infection. We established an epidemiologic link between exposure to rats and human infection by performing nested PCRs that detected S. notomytis in the intraoral swab specimens obtained from rats captured in the patient's house.

Rat Bite Fever Caused by Streptobacillus moniliformis in a Cirrhotic Patient Initially Presenting with Various Systemic Features Resembling Henoch-Schönlein Purpura.

We herein report the case of a 61-year-old Japanese cirrhotic patient who developed rat bite fever (RBF) and whose first presentation was serious clinical features mimicking those of Henoch-Schönlein purpura (HSP). In addition to the critical clinical conditions, since the histopathology from purpuric skin eruptions was not inconsistent with that of HSP, therapy with prednisolone was promptly started in order to prevent his death. However, initial blood culture on admission yielded a small and slow-growing bacterial growth, which was gradually revealed by further subculture to be a peculiar bacterium, Streptobacillus moniliformis, leading to a definitive diagnosis of RBF. After the immediate cessation of prednisolone, the patient was treated with a more appropriate antibiotic and consequently made a full recovery. An immunocompromised condition with seriously decompensated liver cirrhosis together with moderately severe chronic kidney disease (CKD) in this patient probably exacerbated the severity of the disease.

[Infections after bite wounds : For example rat bite fever due to Streptobacillus moniliformis]. / Infektionen nach Bissverletzungen : Zum Beispiel Rattenbissfieber durch Streptobacillus moniliformis.

Rat bite fever due to Streptobacillus moniliformis induces typical but not pathognomonic clinical signs, such as local purulent wound infection followed by maculopapular exanthema, myalgia as well as purulent joint infections. Severe complications, such as osteomyelitis and endocarditis are possible. it seems that this infection is rarely diagnosed but this infection could be much more common because the final diagnostic proof is difficult to achieve. Firstly, the culture of these bacteria is critical because the bacteria are fastidious and secondly the exact differentiation of the isolates is hardly possible by standard laboratory methods. Modern techniques such as mass spectroscopy (MALDI-TOF) and molecular biology allow a precise clarification. Surgical cleansing of infection sites in combination with a rational antibiotic therapy, for example with beta-lactam antibiotics, are generally able to cure the infection if treatment is started early enough. In addition, vaccinations, for example against tetanus and rabies have to be considered in this situation as for all other bite wound infections.

Rat-bite fever due to Streptobacillus notomytis isolated from a human specimen.

Rat-bite fever (RBF) is a disease that usually presents with fever, arthralgia and skin rash. Streptobacillus moniliformis was considered the main cause of RBF among the genus Streptobacillus. Although with similar clinical presentation, RBF due to Streptobacillus notomytis is unusual in humans. To the best of our knowledge, we present a case involving the first isolate of S. notomytis in humans. A 63-year-old woman was admitted to our hospital with fever, rash and polyarthritis. She recalled being bitten by a rat on her finger 5 days before presentation. Clinical manifestations were compatible with rat-bite fever (RBF) and the diagnosis was confirmed by the detection of Streptobacillus species from both blood and pustule samples. Initial polymerase chain reaction tests revealed that the organism was S. moniliformis. However, thorough genetic analysis revealed the organism to be S. notomytis. The condition was successfully treated with ampicillin.

Alternative substrate-bound conformation of bacterial solute-binding protein involved in the import of mammalian host glycosaminoglycans.

Glycosaminoglycans (GAGs), constituted by repeating uronate and amino sugar units, are major components of mammalian extracellular matrices. Some indigenous and pathogenic bacteria target GAGs for colonization to and/or infection of host mammalian cells. In Gram-negative pathogenic Streptobacillus moniliformis, the solute-binding protein (Smon0123)-dependent ATP-binding cassette (ABC) transporter incorporates unsaturated GAG disaccharides into the cytoplasm after depolymerization by polysaccharide lyase. Smon0123, composed of N and C domains, adopts either a substrate-free open or a substrate-bound closed form by approaching two domains at 47° in comparison with the open form. Here we show an alternative 39°-closed conformation of Smon0123 bound to unsaturated chondroitin disaccharide sulfated at the C-4 and C-6 positions of N-acetyl-d-galactosamine residue (CΔ4S6S). In CΔ4S6S-bound Smon0123, Arg204 and Lys210 around the two sulfate groups were located at different positions from those at other substrate-bound 47°-closed conformations. Therefore, the two sulfate groups in CΔ4S6S shifted substrate-binding residue arrangements, causing dynamic conformational change. Smon0123 showed less affinity with CΔ4S6S than with non-sulfated and monosulfated substrates. ATPase activity of the Smon0123-dependent ABC transporter in the presence of CΔ4S6S was lower than that in the presence of other unsaturated chondroitin disaccharides, suggesting that CΔ4S6S-bound Smon0123 was unpreferable for docking with the ABC transporter.

A Case Study of Rat Bite Fever Caused by Streptobacillus moniliformis.

We report a case of rat bite fever, diagnosed based on positive cultures of Streptobacillus moniliformis from blood and synovial fluid. The patient was a 45-year-old man who presented with history of a rat bite and alcoholic liver cirrhosis. He had been bitten on his third finger by a rat, which was caught in a mousetrap installed in his house. Over the course of approximately 2 weeks after the bite, the patient developed fever, rash, and arthralgia. The patient was admitted to our hospital and treated with a combination of ampicillin-sulbactam, vancomycin (VAN), and minocycline (MIN) antibiotics. Initial culture findings from the Anaerobic/F resin blood culture were positive for gram-negative bacillus after overnight incubation. Thus, S. moniliformis infection was suspected, and administration of VAN and MIN was ceased. On hospital day 8, the treatment was switched to oral amoxicillin-clavulanic acid, and the patient was discharged from the hospital. Subsequently, the pathogen was also detected in synovial fluid and identified as S. moniliformis using 16S rRNA sequencing analysis.

A Case of Streptobacillus moniliformis Infection with Cutaneous Leukocytoclastic Vasculitis.

A 71-year-old man presented with a high fever, polyarthralgia, petechiae and palpable purpura accompanied by livedoid change on his legs and feet. Histopathological findings of the purpura revealed perivascular infiltration of neutrophils, mononuclear cells, and nuclear debris, and extravasation of red cells mainly in the upper dermis: all signs consistent with leukocytoclastic vasculitis. Small vessel thrombi, which are characteristic features of septic vasculopathy, were also observed. Direct immunofluorescence showed negative results. Blood culture revealed the growth of gram-negative bacilli. Subsequently, 16S rRNA sequencing of DNA confirmed the organism as Streptobacillus moniliformis, which is the causative pathogen of rat-bite fever. He had frequently encountered wild rats in his house although there was no evidence of rat bite on his body. Empiric therapy with intravenous administration of ceftriaxone in combination with azithromycin hydrate led to a prompt resolution of the symptoms. Precise history-taking related to contact with rats and detection of skin eruptions suggestive of leukocytoclastic vasculitis on the extremities, especially on the feet, can be clues to Streptobacillus moniliformis infection. Familiarity with its cutaneous features is important for early diagnosis; the evidence herein may also help in understanding its underlying pathogenesis.