Emergence of a multidrug-resistant Citrobacter freundii ST8 harboring an unusual VIM-4 gene cassette in Poland.

OBJECTIVES: The growing incidence of multidrug-resistant (MDR) bacteria is an emerging challenge in modern medicine. The utility of carbapenems, which are considered 'last-line' agents, is being diminished by the growing incidence of various resistance mechanisms in Gram-negative bacteria. A molecular investigation was performed of an MDR carbapenem-resistant Citrobacter freundii of sequence type 8 (ST8) isolated from a hematology patient with acute myeloid leukemia. METHODS: Multilocus sequence typing and analysis of the nucleotide sequence of the class I integron were performed using PCR and Sanger sequencing. Transformation of the resistance plasmid isolated following the alkaline lysis method was performed using chemically competent E. coli TOP10. RESULTS: Molecular analysis of the carbapenem-resistant C. freundii revealed the presence of the VIM-4 isoenzyme located on the ∼55-kb transferable resistance plasmid. Interestingly, the blaVIM-4 gene was inserted into an unusual gene cassette containing a 169-bp direct repeat of the 3' segment of the blaVIM-4 gene. CONCLUSIONS: All unusual gene cassettes containing VIM-DR (direct repeat) described thus far have been harbored by non-fermenters, i.e., Acinetobacter and Pseudomonas, underscoring the importance of resistance determinant mobility, which may go even beyond genus, family, and order boundaries. Great efforts need to be taken to explore pathways of resistance to 'last-resort' antimicrobials, especially among clinically relevant pathogens.

Enhanced pretreatment CD25 expression on peripheral blood CD4+ T cell predicts shortened survival in acute myeloid leukemia patients receiving induction chemotherapy.

BACKGROUND: Recently, identification of CD25 (interleukin-2 receptor alpha) expression on leukemic blasts was correlated to early treatment failure and unfavorable outcome in acute myeloid leukemia (AML) patients. Here we wished to determine whether quantification of CD25 on peripheral blood CD4+ T cells could improve prognostication in newly diagnosed AML patients. METHODS: The mean fluorescence intensity (MFI) of CD25 expression and frequencies of peripheral blood CD4+ T cells with varying levels of CD25 and CD127 expression were assessed by flow cytometry in all studied individuals. RESULTS: Using univariate (unadjusted) and multivariate (adjusted) analyses we demonstrated that detection of high pretreatment CD25 expression on circulating CD4+ T cells was associated with significantly decreased survival rate of AML patients subjected to standard induction chemotherapy. These associations held true for both entire group of analyzed AML patients and different subgroups of patients identified by presence or absence of favorable and adverse molecular prognostic factors. CONCLUSIONS: Our data indicate that quantification of CD25 expression on peripheral blood CD4+ T cells could become a novel, easily accessible method of shortened survival prognostication of AML patients subjected to standard cytotoxic therapy.

Prognostic significance of PD-1 expression on peripheral blood CD4+ T cells in patients with newly diagnosed chronic lymphocytic leukemia.

INTRODUCTION: Recent studies in a mouse model of chronic lymphocytic leukemia (CLL) demonstrated that inhibition of the programmed death receptor 1 (PD­1)-PD­L1 axis resulted in correction of leukemia­induced CD8+ T cell­related immune dysfunction and protected mice against CLL development. However, it remains unclear whether CLL development and progression can be also associated with CD4+ T cells expressing PD­1. OBJECTIVES: We aimed to analyze whether a quantitative assessment of CD4+PD­1+ T cells performed at the time of diagnosis can have prognostic significance in patients with CLL. PATIENTS AND METHODS: We examined 56 patients with newly diagnosed CLL at different stages of the disease. The quantitative assessment of PD­1­expressing CD4+ T cells was performed in all patients, using multicolor flow cytometry. RESULTS: We demonstrated that CLL patients with an advanced (high and intermediate risk) stage had a significantly higher number of CD4+PD­1+ T cells compared with subjects with low­grade disease. Importantly, we showed that the number of PD­1­expressing CD4+ T cells in the peripheral blood of patients referred for immediate treatment due to the advanced stage of the disease was significantly higher compared with subjects on watchful waiting. Finally, we found that treatment­naive patients with higher numbers of CD4+PD­1+ T cells at baseline showed a significantly shortened time to the first treatment compared with patients with a low number of CD4+PD­1+ T cells. CONCLUSIONS: Our study showed that the quantative assessment of CD4+PD­1+ T cells in peripheral blood using flow cytometry can facilitate prognostication of patients with newly diagnosed CLL.

Circulating classical CD14++CD16- monocytes predict shorter time to initial treatment in chronic lymphocytic leukemia patients: Differential effects of immune chemotherapy on monocyte-related membrane and soluble forms of CD163.

Three main monocyte subsets: classical CD14++CD16-, intermediate CD14++CD16+ and non-classical CD14+CD16++, differentially regulate tumor growth and survival. Thereby, in the present study we aimed to determine the role of distinct monocyte subsets in the prognostication of chronic lymphocytic leukemia (CLL). Moreover, we set out to analyze the effects of standard immune chemotherapy on different monocyte subsets and levels of membrane-associated and soluble forms of CD163, a monocyte/macrophage-related immunomodulatory protein. We demonstrated that the number of peripheral blood classical CD14++CD16- monocytes assessed at the time of diagnosis was negatively correlated with lymphocytosis and was decreased in the CLL patients who required immediate treatment as opposed to patients who qualified to 'watch and wait' strategy. Notably, lower baseline levels of classical CD14++CD16- monocytes in CLL patients who were qualified for 'watch and wait' therapy were associated with shorter time to initial treatment. Notably, therapy with rituximab, cyclophosphamide and fludarabine resulted in a significant reduction in the number of non-classical CD14+CD16++ monocytes and soluble form of CD163 but upregulation of membrane-associated monocyte CD163. Our data indicate that distinct monocyte subsets and two forms of CD163 are differentially modulated by both CLL and immune chemotherapy. Moreover, we proposed that quantification of classical monocytes at the time of diagnosis contributes to better prognostication of CLL patients.