Whole-Genome Sequencing Snapshot of Clinically Relevant Carbapenem-Resistant Gram-Negative Bacteria from Wastewater in Serbia.

Wastewater (WW) is considered a source of antibiotic-resistant bacteria with clinical relevance and may, thus, be important for their dissemination into the environment, especially in countries with poor WW treatment. To obtain an overview of the occurrence and characteristics of carbapenem-resistant Gram-negative bacteria (CR-GNB) in WW of Belgrade, we investigated samples from the four main sewer outlets prior to effluent into international rivers, the Sava and the Danube. Thirty-four CR-GNB isolates were selected for antimicrobial susceptibility testing (AST) and whole-genome sequencing (WGS). AST revealed that all isolates were multidrug-resistant. WGS showed that they belonged to eight different species and 25 different sequence types (STs), seven of which were new. ST101 K. pneumoniae (blaCTX-M-15/blaOXA-48) with novel plasmid p101_srb was the most frequent isolate, detected at nearly all the sampling sites. The most frequent resistance genes to aminoglycosides, quinolones, trimethroprim-sulfamethoxazole, tetracycline and fosfomycin were aac(6')-Ib-cr (55.9%), oqxA (32.3%), dfrA14 (47.1%), sul1 (52.9%), tet(A) (23.5%) and fosA (50%), respectively. Acquired resistance to colistin via chromosomal-mediated mechanisms was detected in K. pneumoniae (mutations in mgrB and basRS) and P. aeruginosa (mutation in basRS), while a plasmid-mediated mechanism was confirmed in the E. cloacae complex (mcr-9.1 gene). The highest number of virulence genes (>300) was recorded in P. aeruginosa isolates. Further research is needed to systematically track the occurrence and distribution of these bacteria so as to mitigate their threat.

Vaginal epithelioid angiosarcoma: a potential pitfall in gynecologic pathology.

OBJECTIVE: Epithelioid angiosarcoma of the vagina is a rare variant that can easily be misdiagnosed considering the much higher frequency of epithelial neoplasms at that particular site. MATERIAL AND METHODS: We report the case of a 41-year-old gravida 2, para 1, aborta 1, with no prior history of irradiation, who consulted after the discovery of 3 lesions at the lower right portion of the vagina. RESULT: The lesion consisted of epithelioid cells with high-grade nuclei and prominent nucleoli. These cells expressed CD31, CD34, factor VIII, Fli-1, vimentin, smooth muscle actin, and WT-1. Keratin 8/18 was focally positive. They were immunonegative for keratin AE1/AE3, keratin 34ßE12, keratin 7, keratin 20, S100, HMB-45, myogenin, desmin, and human herpesvirus type 8. Polymerase chain reaction-based HPV viral search was also negative. CONCLUSIONS: A broad immunohistochemical panel including antibodies against vascular differentiation markers as well as various cytokeratins allows proper diagnosis of this unusual and aggressive entity.

Pure red cell aplasia and associated thymoma.

Pure red cell aplasia is a rare cause of anemia, caused by an absence of red blood cell precursors in the bone marrow. It is usually a paraneoplastic syndrome, associated most commonly with large-cell granular lymphocyte leukemia but also thymoma. For patients who present both pure red cell aplasia and thymoma, thymectomy leads to an initial remission of the aplasia in 30% of cases. However, sustained remission may require the addition of medications such as corticosteroids, cyclosporine, or cyclophosphamide. We present a case of pure red cell aplasia associated with a thymoma in an otherwise healthy 80 year-old woman.

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue with initial presentation in the pleura.

Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (EMZL/MALT-type) occurs in a wide variety of body sites; it is well recognized as a form of primary lung lymphoma. However, until recently, pleural presentation of this form of low-grade lymphoma has not been documented. A small series of case reports has brought to attention the potential for primary occurrence or initial presentation in the pleura of EMZL/MALT-type. In this report, we describe an additional patient with EMZL/MALT-type with initial pleural presentation and review the literature. Clinicians and pathologists dealing with lymphoproliferative disorders involving the pleura should be aware of this rare entity.

Changes in the lymph node microenvironment induced by oncostatin M.

Oncostatin M (OM) transforms the lymph node (LN) into a "super lymphoid organ" with 2 striking features: massive thymus-independent T-cell development and major expansion of the memory T-cell pool. We report that T-cell development in the LckOM LN is regulated by a cyclooxygenase-2 (COX-2)-dependent neoangiogenesis involving high endothelial venules (HEVs). That LN HEVs are particularlyrich in OM-receptor beta-chain provides aplausible explanation for the fact that extrathymic T-cell development in LckOM mice is limited to the LN. Moreover, we found that increased production of the CCL20 chemokine by LN stromal cells was instrumental in the expansion of the memory phenotype CD4 T-cell pool in LckOM mice. The generality of the latter finding was demonstrated by the fact that CCL20/CCR6 interactions increase the basal proliferation rate of CD62L(lo) CD4 T cells irrespective of their thymic (in non-OM-transgenic mice) or extrathymic (in LckOM mice) origin. To our knowledge, CCL20 is the first molecule found to increase the proliferation of memory phenotype CD4 T cells. These findings identify potential targets for the creation of thymic substitutes (LN HEVs) and for expansion of the CD4 memory T-cell compartment (CCL20).

Cloning and characterization of a family of proteins associated with Mpl.

Thrombopoietin (TPO) controls the formation of megakaryocytes and platelets from hematopoietic stem cells via activation of the c-Mpl receptor and multiple downstream signal transduction pathways. We used two-hybrid screening to identify new proteins that interacted with the cytoplasmic domain of Mpl, and we found a new family of proteins designated A2D (for Ataxin-2 Domain protein). The A2D are 130-kDa proteins that have three regions similar to those of Ataxin-2, the gene product causing familial type 2 spinocerebellar ataxia. A2D has several isoforms with different C-terminal domains, all produced from a single gene by alternative splicing. Northern blotting indicated that the A2D gene is widely expressed in immortalized cell lines and hematopoietic and fetal tissues. A2D proteins were constitutively associated with Mpl in vivo in human hematopoietic UT7 cells. TPO also caused the release of A2D from the activated receptor, and the phosphorylation of A2D on tyrosines residues was dependent on the Mpl C-terminal domain. Finally, A2D bound to the unstimulated erythropoietin receptor, whereas erythropoietin caused dissociation from the erythropoietin receptor, suggesting that A2D proteins are new components of the cytokine signaling system.