Detection of Fusobacterium spp in colorectal tissue samples using reverse transcription polymerase chain reaction with minor groove binder probes: an exploratory research.

An unhealthy microbiome is intimately correlated with several disease states, including colorectal cancer, wherein bacteria might be the key to neoplastic initiation and progression. Recent studies revealed an enrichment of Fusobacterium in colorectal tumor tissues relative to surrounding normal mucosa. Given the available evidence, we conducted an exploratory study quantifying the relative expression of Fusobacterium spp in 28 tissue samples from patients treated at Centro Hospitalar de São João belonging to 4 different groups: adenomas, paired normal tissue from patients with adenomas, carcinomas, and paired normal tissue from patients with colorectal carcinomas. To increase reverse transcription polymerase chain reaction quantification sensitivity, minor groove binders fluorescent probes were used, having in mind its implementation into routine clinical practice. Differences of Fusobacterium spp relative abundance between paired neoplastic lesions/normal tissue were examined by Wilcoxon signed-rank test and for all the other 2-group comparisons the Mann-Whitney U test was used. Most of the adenomas studied belonged to clinical specimens showing either tubular or villous low-grade dysplasia and an enrichment of Fusobacterium relative to paired normal tissue was not found (P = .180). In the carcinoma group, 57% of samples displayed a positive status for this bacterium with the highest burden of detectable Fusobacterium belonging to a specimen with positive regional lymph node metastasis. This is the first Portuguese study confirming a trend toward an overabundance of Fusobacterium in colorectal carcinomas compared to adenomas and paired samples of normal-looking mucosa, in keeping with the role of this bacterium in colorectal carcinogenesis. Further studies are needed to elucidate the relevance of Fusobacterium detection for the prevention and treatment of colorectal cancer.

[A cutaneous infection by Mycobacterium chelonae in a patient with rheumatoid arthritis]. / Infecção cutânea por Mycobacterium chelonae numa doente com artrite reumatóide.

There are no pathognomonic findings for cutaneous infection caused by Mycobacterium chelonae. The type and duration of therapy varies considerably among reports and no single antibiotic is considered the treatment of choice. A 61-year-old patient, suffering from rheumatoid arthritis (treated with metotrexate and salazopyrine), presented with violaceous nodules of the right leg that had been evolving for 6 months. She was underwent several skin biopsies. Tissue culture of the last showed an atypical mycobacteria, identified as M. chelonae. Despite improvement after a two-week course of treatment with clarithromycin, a switch to ciprofloxacin was made because of gastrointestinal intolerance. After 3 months, only slight improvement of the lesions was achieved and clarithromycin was reintroduced; significant clinical improvement occurred by the third month. Clarithromycin was continued a further two months until the patient quit on her own and. no recurrence was observed. Infections caused by M. chelonae frequently occur in the setting of immunological impairment. Contaminated water is the natural reservoir, but we were unable to establish the source of contamination. As was previously described, there was a significant delay between clinical presentation and diagnosis. Thus, a high index of suspicion and multiple biopsies with culture are of paramount importance to confirming the diagnosis.