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.

Mucocele of the appendiceal stump due to benign mucinous cystadenoma

Mucocele of the appendix is a rare lesion, characterized by distension of the lumen due to accumulation of mucus material. Correct preoperative diagnosis is seldom achieved. If left untreated, the mucocele may rupture producing a potentially fatal peritoneal spread. The type of surgical treatment is related to the dimensions and histology of the mucocele. In this paper, the case of a 49-year-old woman, with a previous appendectomy, suffering from a painful mass in the right lower quadrant of the abdomen, is reported. Imaging showed a large, cystic structure at the base of the cecum. Surgery revealed a 8x5.5 cm calcified tumor, which was excided together with the appendiceal remnant. Pathological diagnosis was that of a mucocele arising from the appendiceal stump due to the development of a benign mucinous cystadenoma.