The tigecycline resistance gene tetX has an expensive fitness cost based on increased outer membrane permeability and metabolic burden in Escherichia coli.

Livestock-derived tetX-positive Escherichia coli with tigecycline resistance poses a serious risk to public health. Fitness costs, antibiotic residues, and other tetracycline resistance genes (TRGs) are fundamental in determining the spread of tetX in the environment, but there is a lack of relevant studies. The results of this study showed that both tetO and tetX resulted in reduction in growth and an increased in the metabolic burden of E. coli, but the presence of doxycycline reversed this phenomenon. Moreover, the protection of E. coli growth and metabolism by tetO was superior to that of tetX in the presence of doxycycline, resulting in a much lower competitiveness of tetX-carrying E. coli than tetO-carrying E. coli. The results of RNA-seq showed that the increase in outer membrane proteins (ompC, ompF and ompT) of tetX-carrying E. coli resulted in increased membrane permeability and biofilm formation, which is an important reason for fitness costs. Overall, the increased membrane permeability and metabolic burden of E. coli is the mechanistic basis for the high fitness cost of tetX, and the spread of tetO may limit the spread of tetX. This study provides new insights into the rational use of tetracycline antibiotics to control the spread of tetX.

Prognostic values of interim and post-therapy 18F-FDG PET/CT scanning in adult patients with Burkitt's lymphoma.

BACKGROUND: The prognostic values of interim and post-therapy fluorine-18-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) and PET/computed tomography (CT) scanning have been confirmed in several subtypes of lymphoma. However, its prognostic value in Burkitt's lymphoma has not been clearly defined. The aim of the present study was to assess the prognostic value of PET/CT scanning during different treatment processes of Burkitt's lymphoma. METHODS: A total of 29 adult patients with newly diagnosed Burkitt's lymphoma were retrospectively involved in this study; of them, 23 patients underwent baseline PET/CT, 15 patients underwent mid-therapy PET/CT after 1-4 cycles of chemotherapy, and 17 patients underwent post-therapy PET/CT after all planned first-line chemotherapy cycles. Mid-therapy and post-therapy PET/CT results (positive vs. negative) were visually interpreted according to the criteria of the International Harmonization Project. The reduction in the maximum standardizes uptake values (∆SUVmax) of 25%, 50%, and 75% were regarded as cutoff points. Overall survival (OS) and progression-free survival (PFS) were regarded as the major endpoints. RESULTS: The median OS and PFS were 27.6 months (range 6.5-78.3 months) and 27.2 months (range 3.0-78.3 months), respectively. The median SUVmax of the baseline PET/CT was 18.3 (range 1.6-35.9), whereas the median SUVmax of the mid-therapy and post-therapy PET/CT decreased to 4.0 (range 0-17.6) and 3.0 (range 0-14.5), respectively. The patients' Eastern Cooperative Oncology Group (ECOG) scores (<2 vs. ≥2) were significantly associated with the baseline PET/CT SUVmax. The mid-therapy and post-therapy PET/CT results (positive vs. negative) showed no significant association with OS or PFS. The optimal cutoff ∆SUVmax from the baseline to the post-therapy PET/CT that could predict a change in OS in patients with Burkitt's lymphoma was 50% (P = 0.019). CONCLUSIONS: (18)F-FDG uptake was intense in Burkitt's lymphoma, and there was a significant reduction in SUVmax during the interim and post-therapy PET/CT procedures. A ∆SUVmax of greater than 50% was a favorable cutoff point to predict the OS of Burkitt's lymphoma patients.

Prognostic significance of peripheral monocyte count in patients with extranodal natural killer/T-cell lymphoma.

BACKGROUND: Extranodal natural killer/T-cell lymphoma (ENKL) has heterogeneous clinical manifestations and prognosis. This study aims to evaluate the prognostic impact of absolute monocyte count (AMC) in ENKL, and provide some immunologically relevant information for better risk stratification in patients with ENKL. METHODS: Retrospective data from 163 patients newly diagnosed with ENKL were analyzed. The absolute monocyte count (AMC) at diagnosis was analyzed as continuous and dichotomized variables. Independent prognostic factors of survival were determined by Cox regression analysis. RESULTS: The AMC at diagnosis were related to overall survival (OS) and progression-free survival (PFS) in patients with ENKL. Multivariate analysis identified AMC as independent prognostic factors of survival, independent of International Prognostic Index (IPI) and Korean prognostic index (KPI). The prognostic index incorporating AMC and absolute lymphocyte count (ALC), another surrogate factor of immune status, could be used to stratify all 163 patients with ENKL into different prognostic groups. For patients who received chemotherapy followed by radiotherapy (102 cases), the three AMC/ALC index categories identified patients with significantly different survivals. When superimposed on IPI or KPI categories, the AMC/ALC index was better able to identify high-risk patients in the low-risk IPI or KPI category. CONCLUSION: The baseline peripheral monocyte count is shown to be an effective prognostic indicator of survival in ENKL patients. The prognostic index related to tumor microenvironment might be helpful to identify high-risk patients with ENKL.

Three prognostic factors influence clinical outcomes of primary testicular lymphoma.

The standard treatment of primary testicular lymphoma (PTL) has not been well established. Our study aimed to evaluate the relationship between the prognostic factors and clinical outcomes of PTL. We retrospectively reviewed the clinical records of 43 PTL patients and included the 39 patients who were diagnosed with primary testicular diffuse large B cell lymphoma (DLBCL) for analysis of prognostic factors and assessment of treatment modalities. Cox regression analysis showed that poor ECOG performance status (PS, ≥2), infiltration of adjacent tissues (spermatic cord, epididymis, or scrotum), and bulky disease (tumor mass, >9 cm) were independent predictors of worse overall survival (OS) for primary testicular DLBCL. According to these three factors, the patients were divided into two groups. Rituximab was found to significantly prolong progression-free survival (PFS) in the low-risk group (P = 0.044) but not in the high-risk group (P = 0.748). And the combination therapy for CNS prophylaxis significantly prolonged the survival in the high-risk group (P = 0.005 for OS; P = 0.004 for PFS), but not in the low-risk group (P = 0.092 for OS; P = 0.191 for PFS). ECOG performance status, infiltration of adjacent tissues, and bulky disease are practical prognostic factors of survival in patients with primary testicular DLBCL. The addition of rituximab is more important for the patients without the prognostics factors, and the combination CNS prophylaxis is more significant for the patients with the prognostics factors.

Blood lymphocyte-to-monocyte ratio identifies high-risk patients in diffuse large B-cell lymphoma treated with R-CHOP.

BACKGROUND: Recent research has shown a correlation between immune microenvironment and lymphoma biology. This study aims to investigate the prognostic significance of the immunologically relevant lymphocyte-to-monocyte ratio (LMR), in diffuse large B-cell lymphoma (DLBCL) in the rituximab era. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed retrospective data from 438 newly diagnosed DLBCL patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) therapy. We randomly selected 200 patients (training set) to generate a cutoff value for LMR by receiver operating characteristic (ROC) curve analysis. LMR was then analyzed in a testing set (n = 238) and in all patients (n = 438) for validation. The LMR cutoff value for survival analysis determined by ROC curve in the training set was 2.6. Patients with low LMR tended to have more adverse clinical characteristics. Low LMR at diagnosis was associated with worse survival in DLBCL, and could also identify high-risk patients in the low-risk IPI category. Multivariate analysis identified LMR as an independent prognostic factor of survival in the testing set and in all patients. CONCLUSIONS/SIGNIFICANCE: Baseline LMR, a surrogate biomarker of the immune microenvironment, is an effective prognostic factor in DLBCL patients treated with R-CHOP therapy. Future prospective studies are required to confirm our findings.

High Ki-67 expression in diffuse large B-cell lymphoma patients with non-germinal center subtype indicates limited survival benefit from R-CHOP therapy.

OBJECTIVES: Rituximab has significantly improved the survival of patients with DLBCL, especially those with non-germinal center B-cell-like (non-GCB) subtype. The impact of Ki-67 expression, an index of proliferation, on the clinical outcomes of patients with DLBCL has largely been unexplored. This study aimed to investigate whether Ki-67 expression is an indicator of outcome in DLBCL patients (especially non-GCB DLBCL patients) treated with standard chemotherapy combined with rituximab. METHODS: Expression of Ki-67 protein was examined immunohistochemically in 118 tumor specimens from patients newly diagnosed with DLBCL and treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone). RESULTS: Overall survival (OS) and progression-free survival (PFS) were lower in patients with high Ki-67 expression than in those with low Ki-67 expression (3-year OS: 65.2% vs. 81.7%, P = 0.030; 3-year PFS: 56.4% vs. 73.3%, P = 0.020), similar in patients with GCB subtype and those with the non-GCB subtype (OS: P = 0.330; PFS: P = 0.287). According to Ki-67 expression status by immunophenotype subgroups, patients with high Ki-67 expression in non-GCB subgroup had the most unfavorable PFS and OS, comparing with the other three subgroups (P = 0.004 and P = 0.002, respectively). In multivariate analysis, non-GCB with high Ki-67 expression was an independent prognostic predictor of inferior survival in DLBCL patients treated with R-CHOP. CONCLUSION: For DLBCL patients with non-GCB DLBCL and high Ki-67 expression, the survival benefit from R-CHOP therapy is limited.