Macrolides impact the growth ability of clinical Pseudomonas aeruginosa through quorum-sensing systems.

The aim of the present study was to examine the impact of macrolides on the expression of virulence factors and QS-associated genes in clinical P. aeruginosa isolates. Among 60 clinical P. aeruginosa, pyocyanin production was detected in 27 (45%) isolates, which belonged to various STs. Erythromycin inhibited the production of pigments in 12 out of 27 isolates. Other antibiotic categories didn't have an impact on production of pigments. Additionally, results showed that erythromycin sub-MIC inhibited the growth-rate in 17 isolates. Of note, in six isolates, the inhibition of growth-rate was greater when using both erythromycin and meropenem than using each antibiotic individually. Finally, addition of erythromycin down-regulated the expression of QS-associated genes (65.5%-81.3%) and almost all virulence-associated genes. In conclusion, our results confirmed that macrolides could be used in combination with last-line antibiotics, such as carbapenems, to treat infections caused by multidrug-resistant Gram-negative bacteria.

Solitary fibrous tumor of the liver expressing CD34 and vimentin: a case report.

A case of a successfully treated solitary fibrous tumor (SFT) of the liver is reported. An 82-year-old female presented with left upper abdominal discomfort, a firm mass on palpation, and imaging studies revealed a large tumor, 15 cm in diameter, arising from the left lobe of the liver. A formal left hepatectomy was performed. Microscopic evaluation showed spindle and fibroblast-like cells within the collagenous stroma. Immunohistochemistry disclosed diffuse CD34 and positive vimentin, supporting the diagnosis of a benign SFT. The patient remained well 21 months after surgery. SFT of the liver is a very rare neoplasm of mesenchymal origin. In most cases it is a benign lesion, although some may have malignant histological features and recur locally or metastasize. With less than 30 reported cases in the literature, little can be said regarding its natural history or the benefits of adjuvant radiochemotherapy. Complete surgical resection remains the cornerstone of its treatment.

Primary malignant melanoma of the duodenum: aggressive management and long-term survival of an unusual oncologic entity.

Primary malignant melanoma originating in the small bowel is extremely rare. We report the case of a 55-year-old man who presented with a preoperative bleeding duodenal tumor. A standard pancreaticoduodenectomy was performed. Histopathological examination ascertained the diagnosis of a duodenal malignant melanoma with locoregional lymphatic spread. A thorough postoperative investigation did not reveal any primary melanotic lesions. Thus, the diagnosis of a primary melanoma originating from the duodenum was suggested. Fourteen months after surgery, the patient had no evidence of recurrence. Primary malignant melanoma of the duodenum is an existing, though unusual, oncologic entity. Aggressive surgery remains the treatment of choice offering both symptom palliation and long-term survival.