Rat-bite Fever: A Rare Diagnosis for a Common Pediatric Presentation: Case Report

Introduction: Fever and rash is a common pediatric presentation to the emergency department but can present a diagnostic challenge to the clinician. Here we report the successful identification and treatment of a rare zoonotic exanthem that was facilitated by a thorough history and physical exam. Case Report: Rat-bite fever is a potentially fatal systemic illness characterized by relapsing fever, rash, and migratory polyarthralgias. Treatment includes antibiotics for Streptobacillus moniliformis, the most common pathogen, as well as appropriate hygiene education and prevention strategies. We report a case of S. moniliformis in the absence of an actual rodent bite. Conclusion: Due to the generally non-specific presentation of the illness, as well as the growing trend of caring for domestic rodents, it is crucial that clinicians ask details related to zoonotic and other exposures while obtaining medical histories.

Rat-Bite Fever: Developing and testing a modified time-kill protocol based on Edberg and Edberg 1983 experiemnt in order to test S. moniliformis growth in 0.05% SPS and proposed growth curve

Introduction/Objective Streptobacillus moniliformis is the primary causative agent of rat-bite fever (RBF) and Haverhill fever (HF). Rat-bite fever and Haverhill fever are difficult to diagnose in a clinical setting and are likely severely under-represented and under-reported worldwide. Clinical presentation often includes fever, chills, myalgia, headache, and vomiting. Patients may also develop a maculopapular rash covering their extremities approximately 2-4 days after onset of fever followed by polyarthritis in roughly 50% of patients with a mortality rate of 10-13% if left untreated. This is further complicated by the fact that submission and processing guidelines of clinical samples for the recovery of the organism are based on ‘outdated’ techniques and clinical laboratory methods that are over 50 years removed from current procedures, instrumentation and guidance. Methods/Case Report DNA from collected frozen time-point samples, were collected (n=84) and extracted using an in-house custom protocol utilizing 180 µl of bacterial lysis buffer with 20 µl of PCR grade proteinase K, for a total of 200 µl. The blood culture time-point samples were then thawed on ice, and 200 µl of blood culture sample was then added to the lysis mix, vortexed and incubated at 65°C for 10 minutes (an additional 95°C inactivation step was omitted to avoid whole blood clotting). After incubation, each sample was vortexed briefly again and extracted using the Roche automated MagNA Pure Compact instrument with an initial input volume of 400 µl and stored in a final elution buffer volume of 100 µl. All quantatitive time kill data was colleced via a CDC in-house designed PCR assay developed for S. moniliformis. Results (if a Case Study enter NA) Experimenting with varying amounts of blood inoculum, 10 ml of blood was determined to provide the best results for detection and growth/viability as well as propose a theoretical growth curve for the organism. Conclusion We found that in 100% of the isolates tested (and all the variations of testing within), SPS (up to a concentration of 0.05 % w/v) in commercially available blood culture bottles appeared to be inactivated, allowing for the growth detection and culturing of S. moniliformis using an automated continuous blood culture system when 10 ml of blood was inoculated.

Rat bite fever with osteomyelitis and discitis: case report and literature review

Background Rat bite fever (RBF) is a rare systemic febrile illness transmitted by rats. Streptobacillus moniliformis is a pleomorphic Gram-negative bacillus which is the usual etiologic organism for rat bite fever in the United States. Case presentation Here we present a case of rat bite fever complicated by vertebral osteomyelitis and discitis. The patient revealed an exposure history of being bitten by pet rats. The patient’s symptoms dramatically improved with a six-week course of cephalexin therapy. Conclusions It is important to obtain a thorough zoonotic exposure history and maintain rat bite fever in the differential when considering potential causes of discitis and osteomyelitis.

First investigation of pathogenic bacteria, protozoa and viruses in rodents and shrews in context of forest-savannah-urban areas interface in the city of Franceville (Gabon)

Rodents are reservoirs of numerous zoonotic diseases caused by bacteria, protozoans, or viruses. In Gabon, the circulation and maintenance of rodent-borne zoonotic infectious agents are poorly studied and are often limited to one type of pathogen. Among the three existing studies on this topic, two are focused on a zoonotic virus, and the third is focused on rodent Plasmodium. In this study, we searched for a wide range of bacteria, protozoa and viruses in different organs of rodents from the town of Franceville in Gabon. Samples from one hundred and ninety-eight (198) small mammals captured, including two invasive rodent species, five native rodent species and 19 shrews belonging to the Soricidae family, were screened. The investigated pathogens were bacteria from the Rickettsiaceae and Anaplasmataceae families, Mycoplasma spp., Bartonella spp., Borrelia spp., Orientia spp., Occidentia spp., Leptospira spp., Streptobacillus moniliformis, Coxiella burnetii, and Yersinia pestis; parasites from class Kinetoplastida spp. (Leishmania spp., Trypanosoma spp.), Piroplasmidae spp., and Toxoplasma gondii; and viruses from Paramyxoviridae, Hantaviridae, Flaviviridae and Mammarenavirus spp. We identified the following pathogenic bacteria: Anaplasma spp. (8.1%; 16/198), Bartonella spp. (6.6%; 13/198), Coxiella spp. (5.1%; 10/198) and Leptospira spp. (3.5%; 7/198); and protozoans: Piroplasma sp. (1%; 2/198), Toxoplasma gondii (0.5%; 1/198), and Trypanosoma sp. (7%; 14/198). None of the targeted viral genes were detected. These pathogens were found in Gabonese rodents, mainly Lophuromys sp., Lemniscomys striatus and Praomys sp. We also identified new genotypes: Candidatus Bartonella gabonensis and Uncultured Anaplasma spp. This study shows that rodents in Gabon harbor some human pathogenic bacteria and protozoans. It is necessary to determine whether the identified microorganisms are capable of undergoing zoonotic transmission from rodents to humans and if they may be responsible for human cases of febrile disease of unknown etiology in Gabon.