Rat bite fever caused by Streptobacillus moniliformis in a child: human infection and rat carriage diagnosed by PCR

Management Strategies for Common Animal Bites in Pediatrics: A Narrative Review on the Latest Progress

Animal bites are a common reason for children to visit primary care and emergency departments. Dog bites are the most prevalent, followed by cat bites at 20-30%. Other animals such as bats, monkeys, snakes, and rats collectively contribute less than 1% of cases. Hospitalization is necessary in only 4% of animal bite incidents. The main aim of this narrative review is to summarize the main protocols currently followed in pediatrics in cases involving the most common bites from different animal species. Analysis of the literature showed that the management of common animal bites in children presents a multifaceted challenge requiring a comprehensive understanding of the epidemiology, clinical presentation, and treatment modalities associated with each specific species. Effective wound management is paramount in reducing the risk of infection and promoting optimal healing outcomes. Additionally, tetanus vaccination status should be assessed and updated as necessary, and prophylactic antibiotics may be indicated in certain cases to prevent secondary infections. Furthermore, the role of rabies prophylaxis cannot be overstated, particularly in regions where rabies is endemic or following bites from high-risk animals. In addition to medical management, psychosocial support for both the child and their caregivers is integral to the overall care continuum. Future studies exploring the efficacy of novel treatment modalities, such as topical antimicrobial agents or advanced wound dressings, may offer new insights into optimizing wound healing and reducing the risk of complications.

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.

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.

Prevalence and Diversity of the Streptobacillus Rat-bite Fever Agent, in Three Invasive, Commensal Rattus Species from South Africa

Rat-bite fever is an over-looked, global zoonotic disease that has a mortality rate of up to 13%, if untreated. Historically, this rat-borne disease has been attributed to one of two causative agents, Streptobacillus moniliformis or Spirillum minus. Given the confirmed presence of multiple invasive Rattus host species, high rat densities in urban, informal human settlements and increasing reports of rat bites in South Africa, we undertook a retrospective assessment of Streptobacillus in rats sampled from 16 urban sites, in Gauteng, the smallest but most populous Province in South Africa. Using a multi-gene PCR-sequencing approach, we confirmed Streptobacillus presence in 50.9% of oral swabs from three rat species and the presence of two Streptobacillus species, viz.S. moniliformis and S. notomytis. The two members of the cryptic Rattus rattus species complex (R. rattus and R. tanezumi), which are morphologically indistinguishable from each other, had markedly different colonization rates. Whereas 48.6% of rats from this species complex were Streptobacillus-positive, only 32.3% of Rattus tanezumi were positive compared to 61.5% R. rattus. Rattus norvegicus had an intermediate prevalence of 55.6%. Phylogenetic analysis of four gene regions (16S rRNA, gyrB, groEL, recA) identified two discrete lineages; S. moniliformis occurred exclusively in R.norvegicus, and S. notomytis was restricted to the two members of the R. rattus species complex; this represents the first report of Streptobacillus in R. tanezumi. These results highlight a largely overlooked zoonotic threat posed by invasive rats and confirm the presence of two discrete and potentially host-specific Streptobacillus lineages in South Africa.

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.

A Teenager With Sacroileitis, Rash and Fever Caused by Streptobacillus moniliformis Bacteremia

We report a rare case of sacroileitis in a teenager resulting from Streptobacillus moniliformis bacteremia, identified by matrix-assisted laser desorption/ionization-time of flight. We discuss the challenges of making this diagnosis and review the literature on rat bite fever.

The rise of the rats: A growing paediatric issue

Rat bite fever (RBF), a systemic infection of Streptobacillus moniliformis or Spirillum minus characterized by fever, arthralgias and petechial-purpuric rash on the extremities, carries a mortality rate of 7% to 10% if untreated. In Canada, one adult and two paediatric cases of RBF have been reported since 2000. In recent years, pet rats have become quite popular among children, placing them at an increased risk for RBF. Thus, paediatricians need to be more wary of the potential for RBF in their patients. In the present report, a culture-confirmed case of RBF and two additional cases of suspected infection are described.

Characterization of β-galactoside phosphorylases with diverging acceptor specificities

Glycoside phosphorylases are a special group of carbohydrate-active enzymes, with characteristics in between those of glycoside hydrolases and glycosyl transferases. The phosphorylases from family GH-112 are exceptional because they employ galactose-1-phosphate instead of glucose-1-phosphate as glycosyl donor. Different acceptor specificities have been observed in this family, ranging from l-rhamnose to GlcNAc, GalNAc and a combination of the latter. Three new phosphorylases from previously unexplored branches of the phylogenetic tree of family GH-112 have now been characterized to shed more light on this divergence in acceptor specificity. The enzymes from Erysipelothrix rhusiopathiae and Streptobacillus moniliformis were found to prefer GalNAc as acceptor, while that from Anaerococcus prevotii displays similar activities on GalNAc and GlcNAc. These results confirm the correlation between the amino acid residue at position 162 and the enzyme's specificity, i.e. a threonine in the former group and a valine in the latter. However, mutagenesis of residue 162 did not allow the rational transformation of the substrate preference, as the substitution of valine by threonine in the enzyme from Bifidobacterium longum did not tighten its specificity towards GalNAc. Unexpectedly, introducing an isoleucine at position 162 increased the preference for GlcNAc as acceptor, which illustrates that the structure-function relationships in β-galactoside phosphorylases are not yet completely understood. Several other positions have also been examined by mutational analysis but true determinants of the acceptor specificity in family GH-112 could not be identified.

Rat bite fever

Rat bite fever (RBF) is a bacterial zoonosis for which two causal bacterial species have been identified: Streptobacillis moniliformis and Spirillum minus. Haverhill fever (HF) is a form of S. moniliformis infection believed to develop after ingestion of contaminated food or water. Here the infectious agents, their host species, pathogenicity (virulence factors and host susceptibility), diagnostic methods, therapy, epidemiology, transmission and prevention are described. Special emphasis is given on information from the field of laboratory animal microbiology and suggestions for future research.

Detection of Streptobacillus spp. in feral rats by specific polymerase chain reaction

Streptobacillus moniliformis is an etiological agent of rat-bite fever and Haverhill fever in human infection. As the currently available methods for identifying the causative bacteria are not satisfactory, we attempted to establish them by PCR using newly designed primers for the 16S rRNA gene of S. moniliformis. We then determined the prevalence of Streptobacillus spp. in two species of feral rats that inhabit an urban region in Japan, because information on the prevalence of the bacteria in feral rats is obscure. The use of PCR with newly designed primers showed that an extremely high proportion of R. norvegicus harbored the bacteria (61/66, 92%), whereas the prevalence was only 58% in R. rattus (30/52). The nucleotide sequence analysis of the 16S rRNA gene of Streptobacillus spp. isolated from oral swabs of feral rats showed at least two different types of bacteria among isolates from R. norvegicus and R. rattus.

Streptobacillus moniliformis septic arthritis: a clinical entity distinct from rat-bite fever?

BACKGROUND

Streptobacillus moniliformis is a zoonotic agent associated with rodent contacts. Although it is more commonly reported to cause rat-bite fever with reactive arthritides, it can also lead to pyogenic infection of the joints.

CASE PRESENTATION

We present a lady with past history of osteoarthritis developing streptobacillary septic arthritides of the right knee and left wrist, and required antibiotic and arthrotomy for treatment. We also review 11 previously reported cases of streptobacillary septic arthritis to discuss the characteristics, treatment, prognosis of the infection, and illustrates the differences between streptobacillary rat-bite fever and septic arthritis. Among this patient population, most patients had potential contact with rats (91.6%). The knee is the most commonly affected joint (58.3%), and 83.3% patients having polyarticular involvement. As opposed to rat-bite fever, fever and rash was only present in 58.3% and 16.7% of patients respectively. S. moniliformis bacteremia is uncommon (8.4%) and the prognosis is good.

CONCLUSION

Arthrocentesis is useful in distinguishing streptobacillary septic arthritis from reactive arthritis of rat-bite fever. The sole use of commercial media containing sodium polyanethol sulfonate may render the bacterial culture negative. A detailed history of possible exposure to rodents should be elicited from patients with arthritis in order to facilitate microbiologic diagnosis.

Rapid identification of Fusobacterium nucleatum and Fusobacterium necrophorum by fluorescence in situ hybridization

Identification of clinically relevant Fusobacterium spp. is hampered by their slow growth, their frequent occurrence in polymicrobial culture, and the low reliability of biochemical differentiation methods. A newly developed fluorescence in situ hybridization (FISH) assay allowed reliable and rapid identification of Fusobacterium necrophorum and Fusobacterium nucleatum from culture. Preliminary results show that the method offers the perspective for direct detection of these pathogens in blood cultures and abscess aspirates.

Rat bite fever and Streptobacillus moniliformis

Rat bite fever, caused by Streptobacillus moniliformis, is a systemic illness classically characterized by fever, rigors, and polyarthralgias. If left untreated, it carries a mortality rate of 10%. Unfortunately, its nonspecific initial presentation combined with difficulties in culturing its causative organism produces a significant risk of delay or failure in diagnosis. The increasing popularity of rats and other rodents as pets, together with the risk of invasive or fatal disease, demands increased attention to rat bite fever as a potential diagnosis. The clinical and biological features of rat bite fever and Streptobacillus moniliformis are reviewed, providing some distinguishing features to assist the clinician and microbiologist in diagnosis.