An Unusual Trigger of Grover's Disease (GD).

Grover's disease (GD) is a rare skin condition that presents as a pruritic, erythematous papular, or papulovesicular rash. We report a unique case of GD triggered by honeybee stings. An 80-year-old Caucasian male presented with a pruritic papulovesicular rash on his trunk and arms after being stung by honeybees. He had a history of honeybee venom allergy and developed immediate erythema at the sting sites, which progressed over two days. His laboratory tests were unremarkable, including a complete blood count and comprehensive metabolic profile. Despite using oral antihistamines, emollients, and topical steroids, his rash continued to progress onto his neck, face, scalp, and back. A skin biopsy of the rash revealed suprabasilar and intraspinous acantholysis with focal corps ronds and upper dermis lymphocytic infiltrate -- the histopathologic finding of GD. He had failed first-line treatment for GD. However, after five months and significant morbidity, he was successfully treated with systemic steroids, high-potency topical steroids, emollients, and antihistamines for extensive and prolonged GD. This case report highlights honeybee venom as a possible trigger of GD and discusses a potential immune-mediated etiopathogenesis, which can be used to guide further research and management of this rare disease.

Transcriptomic analysis of triclosan-susceptible and -tolerant Escherichia coli O157:H19 in response to triclosan exposure.

Triclosan is an active agent that is commonly found in biocide formulations which are used by the food industry to control microbial contamination. The aim of this study was to use microarray analysis to compare gene expression between a triclosan-susceptible Escherichia coli O157:H19 isolate (minimum inhibitory concentration [MIC] 6.25 µg/ml) and its in vitro generated triclosan-tolerant mutant (MIC >8,000 µg/ml). Gene expression profiling was performed on the wild-type and mutant isogenic pairs after 30 min exposure to the parent MIC for triclosan and an untreated control. Microarray analysis was carried out using the Affymetrix GeneChip E. coli Genome 2.0 Array, and differential expression of genes was analyzed using the pumaDE method in Bioconductor R software. Wild-type gene expression was found to be significantly different from the triclosan-tolerant mutant for a large number of genes, even in the absence of triclosan exposure. Significant differences were observed in the expression of a number of pathway genes involved in metabolism, transport, and chemotaxis. In particular, gene expression in the triclosan-tolerant mutant was highly up-regulated for 33 of 38 genes belonging to the flagellar assembly pathway. The presence of extended flagella in the mutant isolate was confirmed visually by transmission electron microscopy, although no significant difference was observed in the motility of the parent and mutant at low levels of triclosan. Data from this study show that at a transcriptomic level, a triclosan-tolerant E. coli O157:H19 mutant is significantly different from the wild-type strain in a number of different pathways, providing an increased understanding of triclosan tolerance.

In vitro studies on the effect of pH and volatile fatty acid concentration, as influenced by diet, on the survival of inoculated nonacid- and acid-adapted Salmonella in bovine rumen fluid and feces.

The aim of this study was to examine the effect of pH and volatile fatty acids concentrations, as influenced by bovine diet, on the survival of Salmonella in inoculated rumen fluid and feces, thus providing preliminary data on the potential application of dietary manipulation as a preharvest control strategy to reduce Salmonella contamination at slaughter. The in vitro survival of nonacid- and acid-adapted (AA) Salmonella cocktails (Salmonella serovars: Dublin, Enteritidis, Newport, Typhimurium, and Typhimurium DT104) in rumen fluid and feces, collected from fistulated cattle fed five different diets ([1] grass, [2] grass + concentrate, [3] grass silage, [4] hay, and [5] a high grain diet), was examined at 6°C and 15°C (feces) and at 37°C (rumen fluid). The pH of the rumen fluid ranged from 5.77 to 6.61 and the feces from 6.86 to 7.06. Salmonella D-values in rumen fluid were statistically similar, regardless of dietary source. Although prolonged survival (up to 84 days) was observed in feces, diet did affect survival with significantly (p < 0.05) higher D-values obtained in feces from diets 3 and 4 (AA cells at 6°C) and significantly (p < 0.05) lower D-values for diet 5 (AA cells at 15°C). It was concluded that changes in rumen pH and volatile fatty acids profile and concentrations, based on dietary manipulation, may not reduce the persistence and dissemination of Salmonella in cattle.