An unusual cause of reactive arthritis with urticarial: A case report

Metataxomics reveals Blastocystis subtypes mixed infections in Colombian children

Blastocystis sp., is an intestinal protist with a broad host range and a high prevalence in human populations worldwide, even in developed Western countries. The publication of conflicting evidence has divided the scientific community about the pathogenic role of this parasite. Even though, genetic studies on Blastocystis sp. revealed associations between genotypes and different pathogenic profiles. Conventionally, the detection of this parasite is based on microscopic or PCR methods, which offer meager or null performance in detecting mixed infections. In this work, we applied a metataxonomic NGS approach targeting the V4 region of the eukaryotic SSU-rRNA gene and classical phylogenetic methods. This approach allowed us to detect Blastocystis sp. in stool samples from infected children living in an urban setting in the city of Medellin attending the same daycare center. Phylogenetic analysis identified the subtypes present in the children as ST1, ST2, and ST3. Besides, mixed infections of subtypes ST1 + ST3 were spotted in 16% of the analyzed stool samples.

A case of reactive arthritis caused by a perianal abscess

Reactive arthritis is an immune-mediated aseptic arthritis resulting from either genitourinary or intestinal tract in a genetically susceptible host. Reactive arthritis is not uncommon, and the most common infectious agents are Chlamydia trachomatis, Salmonella, Yersinia, and Shigella, some new infectious agents include Staphylococcus lugdunensis, Rothia mucilaginosa, and umbilical cord-derived Wharton's jelly, as well as the SARS-CoV-2 virus, which has been more studied in recent years. We found that reactive arthritis caused by infection of perianal abscesses is very rare and few cases have been described in the medical literature. We report a 21-year-old man with polyarticular swelling and pain, and subcutaneous hematoma at his right ankle joint; he was considered reactive arthritis. After treating with non-steroidal anti-inflammatory drugs, sulfasalazine, surgery, and antibiotics, the patient's arthralgia gradually improved and the symptoms largely disappeared at the 1-month follow-up.

Decreased fecal calprotectin levels in Spondyloarthritis patients colonized by Blastocystis spp

Spondyloarthritis (SpA) is a group of chronic inflammatory systemic diseases mainly characterized by inflammation in the spine and/or peripheral joints. Although a link between SpA-pathogenesis, intestinal inflammation and gut dysbiosis has been proposed, studies have been focused on bacteria-host interactions and very little has been reported regarding intestinal parasites. Here, intestinal parasitic infection of 51 SpA-patients were evaluated and compared to healthy control individuals. No significant differences in the frequency of any parasite between SpA-patients and control individuals were found. Significantly higher levels of fecal calprotectin (FCP) were found in the SpA-patients compared to the control individuals. However, FCP levels were the same when comparing SpA-patients and control individuals, both colonized by Blastocystis spp. On the other hand, when comparing Blastocystis spp. colonized and Blastocystis spp. free SpA-patients, FCP levels were significantly higher in those Blastocystis spp. free. Without ignoring the small sample size as a study limitation, the results showed that in the SpA-patients colonized by Blastocystis spp., the FCP levels were significantly lower than those in the Blastocystis spp. free group and comparable to those in the control group. These findings seem to suggest a relationship between Blastocystis spp. and intestinal inflammation in SpA-patients, but studies intended to explore that interaction specifically should be designed.

Reactive Arthritis Update: Spotlight on New and Rare Infectious Agents Implicated as Pathogens

Purpose of Review

This article presents a comprehensive narrative review of reactive arthritis (ReA) with focus on articles published between 2018 and 2020. We discuss the entire spectrum of microbial agents known to be the main causative agents of ReA, those reported to be rare infective agents, and those reported to be new candidates causing the disease. The discussion is set within the context of changing disease terminology, definition, and classification over time. Further, we include reports that present at least a hint of effective antimicrobial therapy for ReA as documented in case reports or in double-blind controlled studies. Additional information is included on microbial products detected in the joint, as well as on the positivity of HLA-B27.

Recent Findings

Recent reports of ReA cover several rare causative microorganism such as Neisseria meningitides, Clostridium difficile, Escherichia coli, Hafnia alvei, Blastocytosis, Giardia lamblia, Cryptosporidium, Cyclospora cayetanensis, Entamoeba histolytica/dispar, Strongyloides stercoralis, β-haemolytic Streptococci, Mycobacterium tuberculosis, Mycoplasma pneumoniae, Mycobacterium bovis bacillus Calmette-Guerin, and Rickettsia rickettsii. The most prominent new infectious agents implicated as causative in ReA are Staphylococcus lugdunensis, placenta- and umbilical cord–derived Wharton’s jelly, Rothia mucilaginosa, and most importantly the SARS-CoV-2 virus.

Summary

In view of the increasingly large spectrum of causative agents, diagnostic consideration for the disease must include the entire panel of post-infectious arthritides termed ReA. Diagnostic procedures cannot be restricted to the well-known HLA-B27-associated group of ReA, but must also cover the large number of rare forms of arthritis following infections and vaccinations, as well as those elicited by the newly identified members of the ReA group summarized herein. Inclusion of these newly identified etiologic agents must necessitate increased research into the pathogenic mechanisms variously involved, which will engender important insights for treatment and management of ReA.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11926-021-01018-6.