Relation between tetR and tetA expression in tetracycline resistant Escherichia coli

BACKGROUND: Tetracyclines are among the most used antibiotics in livestock worldwide. Resistance is widely disseminated in Escherichia coli, where it is generally mediated by tetracycline efflux pumps, such as TetA. Expression of tetracycline efflux pumps is tightly controlled by the repressor TetR, which has been shown to be tetracycline-responsive at sub-MIC tetracycline concentrations. The objective of this study was to investigate the effects of increasing tetracycline concentrations on the growth of TetA-producing E. coli, and to determine how expression of tetA and tetR related to each other in different growth phases in the presence of tetracycline. RESULTS: A tetracycline resistant E. coli strain containing tetA and tetR on the chromosome was constructed and cultured in the presence of increasing concentrations of tetracycline. Expression of tetR and tetA was measured at four time points in different growth phases by quantitative real-time PCR. The TetA-producing E. coli exhibited prolonged lag phase with increasing concentrations of tetracycline, while expression of tetA and tetR increased and decreased, respectively, with increasing tetracycline concentration. The levels of tetA and tetR mRNA varied depending on growth phase, resulting in a gradual decrease of the tetA/tetR ratio from approximately 4 in the lag phase to approximately 2 in the stationary phase. CONCLUSION: This study shows that the expression of tetR and tetA is tetracycline concentration- and growth phase-dependent, contributing to improved understanding of the relationships between E. coli growth, tetracycline exposure and expression of tetracycline resistance. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12866-016-0649-z) contains supplementary material, which is available to authorized users

Comparative effectiveness of antibiotic prophylaxis for preventing serious adverse events after primary total hip arthroplasty:a systematic review and network meta-analysis of randomized trials

Background and purpose — The optimal duration of antibiotic prophylaxis for reducing serious adverse events (SAEs) after total hip arthroplasty (THA) is unclear. We aimed to assess the comparative effectiveness of different strategies of antibiotic prophylaxis in preventing SAEs after THA. Methods — We searched Medline, Embase, CENTRAL, and the Clinical Trial Registration Database for randomized controlled trials evaluating antibiotic prophylaxis in patients undergoing primary THA. Two authors independently screened, extracted data, and assessed the risk of bias. We defined SAEs as prosthetic joint infections, other serious infections, major cardiovascular events, venous thromboembolisms, or mortality. The primary summary measures were odds ratios (ORs) with 95% confidence intervals (CI). The evidence was assessed using the confidence in network meta-analysis (CINeMA) framework. Results — Of 6,131 identified citations, 10 trials of 2-group comparisons were included, involving 9,106 patients. Duration of antibiotics was grouped as follows: placebo (3), a single dose (3), multiple doses ≤ 24 hours (6), multiple doses (&gt; 1 day) (6), and bone cement with antibiotics (2). Compared with placebo, point estimates suggest lower odds of SAEs after THA for most antibiotic strategies, except multiple doses &gt; 1 day. Multiple doses showed no clear evidence of superiority to single dose: OR (multiple doses ≤ 24 hours) = 0.87 (CI 0.20–3.73; very low) or over more days (&gt; 1 day) OR = 0.40 (CI 0.07–2.42; very low) nor were multiple doses &gt; 1 day superior to multiple doses ≤ 24 hours, OR = 0.46 (0.11–1.90; very low). Conclusion — Relative to placebo, point estimates suggested that most antibiotic prophylaxis regimens may reduce SAEs after THA, with no clear evidence of added benefit from multiple doses. These findings should be interpreted with caution due to the lack of precision and the corresponding very low certainty of evidence for some comparisons.</p

Internal mammary node irradiation in 4541 node-positive breast cancer patients treated with newer systemic therapies and 3D-based radiotherapy (DBCG IMN2): a prospective, nationwide, population-based cohort study

BackgroundInternal mammary node irradiation (IMNI) improves overall survival (OS) in node-positive breast cancer patients. However, the effect is not documented in breast cancer patients treated with newer systemic therapies and 3D-based radiotherapy (RT). Therefore, the Danish Breast Cancer Group (DBCG) IMN2 study aimed to investigate the effect of IMNI in node-positive breast cancer patients treated with newer systemic therapies and 3D-based RT.MethodsDBCG IMN2 was a nationwide population-based cohort study prospectively allocating node-positive breast cancer patients with right-sided tumours to IMNI and patients with left-sided tumours to no IMNI in six RT centres. Exclusion criteria were prior malignancies, bilateral breast cancer, neoadjuvant systemic therapy, recurrence before RT, or non-standard RT. Systemic treatment included taxane-based chemotherapy, aromatase inhibitors, and trastuzumab. The primary end-point was OS. Secondary endpoints were breast cancer mortality and distant metastasis. Cox regression analyses were used for adjusted hazard ratios (HR). Clinicaltrial.gov ID: NCT06549920.FindingsIn the period January 2007–May 2014, a total of 4541 patients were included. Patient characteristics were distributed evenly between right- and left-sided patients. Median follow-up was 13.7 years for OS. Survival rates at 15 years were 65.0% in patients with IMNI and 60.8% without leading to an adjusted HR of 0.85 (95% CI, 0.76–0.94; p = 0.0016) for OS. Corresponding HRs were 0.84 (95% CI, 0.74–0.95; p = 0.0077) for breast cancer mortality and HR 0.87 (95% CI, 0.78–0.98; p = 0.026) for distant metastasis. No subgroups were identified for the omission of IMNI. The 15-year cumulative incidence of death from ischemic or valvular heart disease was 0.2% (95% CI, 0.0–0.5) in right-sided and 0.7% (95% CI, 0.4–1.2) in left-sided patients.InterpretationIMNI reduced distant metastasis and breast cancer mortality and improved OS in node-positive breast cancer patients, despite treatment with newer systemic therapies and 3D-based RT.FundingThis work was supported by the Danish Cancer Society and Department of Clinical Medicine, Aarhus University, Denmark

Quality assurance of internal mammary node irradiation in the DBCG IMN2 study

PURPOSE/OBJECTIVE: The Danish Breast Cancer Group (DBCG) IMN2 study investigated the gain from internal mammary node irradiation (IMNI) in node-positive breast cancer patients. IMNI was indicated in right-sided patients, but not in left-sided. Target volume delineations were based on bony landmarks in contrast to the contemporary vessel-based ESTRO consensus guideline. Our objective was to compare IMNI doses in right-sided versus left-sided patients.MATERIAL/METHODS: Treatment plans and delineated structures including CTVn_IMN (IMN_old) from 2008 to 2014 were collected from the DBCG RT Nation study. During the study period, IMN_old was only delineated in right-sided patients. Right and left-sided CTVn_IMN structures were auto-segmented following the ESTRO guidelines (IMN_ESTRO). Due to cranial discordance between IMN_old and IMN_ESTRO, the IMN_ESTRO models were separated into IMN_ESTRO_cranial and IMN_ESTRO_intercostal space(IC)1-3, IC1-4, and IC4_only.RESULTS: Treatment plans for 2837 patients were available (62.5 % of patients in the IMN2 study). In right-sided patients, the median IMN_old dose coverage (92.4 %) was higher than IMN_ESTRO (71.7 %), p &lt; 0.001. Dose coverage in IMN_ESTRO_IC1-3 was comparable to IMN_old. Comparing IMN_ESTRO_IC1-3 in all patients by laterality, the median CTVn_V90% was 94.6 % (IQR 64.8-100.0) in right-sided patients and 20.4 % (IQR 0.9-55.8) in left-sided patients, p &lt; 0.001. For right-sided patients, median CTV_V90% was 82.3 % in IMN_ESTRO_IC4_only. Median mean heart doses were lower in right-sided patients (1.2 Gy) than in left-sided (2.3 Gy), p &lt; 0.001. Median mean lung doses were higher in right-sided patients (16.0 Gy) than in left-sided (12.7 Gy), p &lt; 0.001.CONCLUSION: For IMN_ESTRO_IC1-3, we found a significantly higher IMN dose coverage in right-sided than in left-sided patients supporting treatment according to study guidelines in the DBCG IMN2 study

Impact of fibre and red/processed meat intake on treatment outcomes among patients with chronic inflammatory diseases initiating biological therapy:A prospective cohort study

Background: Biologic disease-modifying drugs have revolutionised the treatment of a number of chronic inflammatory diseases (CID). However, up to 60% of the patients do not have a sufficient response to treatment and there is a need for optimization of treatment strategies.Objective: To investigate if the treatment outcome of biological therapy is associated with the habitual dietary intake of fibre and red/processed meat in patients with a CID.Methods: In this multicentre prospective cohort study, we consecutively enrolled 233 adult patients with a diagnosis of Crohn's Disease, Ulcerative Colitis, Rheumatoid Arthritis (RA), Axial Spondyloarthritis, Psoriatic Arthritis and Psoriasis, for whom biologic therapy was planned, over a 3 year period. Patients with completed baseline food frequency questionnaires were stratified into a high fibre/low red and processed meat exposed group (HFLM) and an unexposed group (low fibre/high red and processed meat intake = LFHM). The primary outcome was the proportion of patients with a clinical response to biologic therapy after 14-16 weeks of treatment.Results: Of the 193 patients included in our primary analysis, 114 (59%) had a clinical response to biologic therapy. In the HFLM group ( N = 64), 41 (64%) patients responded to treatment compared to 73 (56%) in the LFHM group ( N = 129), but the difference was not statistically significant (OR: 1.48, 0.72-3.05). For RA patients however, HFLM diet was associated with a more likely clinical response (82% vs. 35%; OR: 9.84, 1.35-71.56). Conclusion: Habitual HFLM intake did not affect the clinical response to biological treatment across CIDs. HFLM diet in RA patients might be associated with better odds for responding to biological treatment, but this would need confirmation in a randomised trial.Trial registration: (clinicaltrials.gov), identifier [NCT03173144].</p

Microfibrillar-associated protein 4 as a predictive biomarker of treatment response in patients with chronic inflammatory diseases initiating biologics:secondary analyses based on the prospective BELIEVE cohort study

BACKGROUND: Currently, there are no reliable biomarkers for predicting treatment response in chronic inflammatory diseases (CIDs).OBJECTIVE: To determine whether serum microfibrillar-associated protein 4 (MFAP4) levels can predict the treatment response to biological therapy in patients with CIDs.METHODS: The BELIEVE study was originally designed as a prospective, multi-center cohort study of 233 patients with either rheumatoid arthritis, psoriatic arthritis, psoriasis, axial spondyloarthritis, Crohn's disease, or ulcerative colitis, initiating treatment with a biologic agent (or switching to another). Clinical assessment and blood sample collection were performed at baseline and 14-16 weeks after treatment initiation. The primary analyses included participants with available blood samples at baseline; missing data were handled as non-responders. The patients were stratified into the upper tertile of serum MFAP4 (High MFAP4) versus a combined category of middle and lower tertiles (Other MFAP4). The primary outcome was the proportion of patients with clinical response to biologic therapy after 14-16 weeks.RESULTS: 211 patients were included in the primary analysis population. The mean age was 43.7 (SD: 14.8) years, and 120 (59%) were female. Positive treatment response was observed in 41 (59%) and 69 (49%) for High MFAP4 and Other MFAP4, respectively. When adjusting for pre-specified variables (CID, age, sex, smoking status, and BMI), the adjusted OR was 2.28 (95% CI: 1.07 to 4.85) for a positive treatment outcome in the High MFAP4 group.CONCLUSION: A high MFAP4 status before initiating biological treatment is associated with a positive clinical response, when adjusting for confounding factors.</p

Asparaginase-Associated Pancreatitis in Acute Lymphoblastic Leukemia : Results From the NOPHO ALL2008 Treatment of Patients 1-45 Years of Age

PURPOSE Asparaginase-associated pancreatitis (AAP) is common in patients with acute lymphoblastic leukemia (ALL), but risk differences across age groups both in relation to first-time AAP and after asparaginase re-exposure have not been explored. PATIENTS AND METHODS We prospectively registered AAP (n = 168) during treatment of 2,448 consecutive ALL patients aged 1.0-45.9 years diagnosed from July 2008 to October 2018 and treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL2008 protocol. RESULTS Compared with patients aged 1.0-9.9 years, adjusted AAP hazard ratios (HRa) were associated with higher age with almost identical HRa (1.6; 95% CI, 1.1 to 2.3; P = .02) for adolescents (10.0-17.9 years) and adults (18.0-45.9 years). The day 280 cumulative incidences of AAP were 7.0% for children (1.0-9.9 years: 95% CI, 5.4 to 8.6), 10.1% for adolescents (10.0 to 17.9 years: 95% CI, 7.0 to 13.3), and 11.0% for adults (18.0-45.9 years: 95% CI, 7.1 to 14.9; P = .03). Adolescents had increased odds of both acute (odds ratio [OR], 5.2; 95% CI, 2.1 to 13.2; P = .0005) and persisting complications (OR, 6.7; 95% CI, 2.4 to 18.4; P = .0002) compared with children (1.0-9.9 years), whereas adults had increased odds of only persisting complications (OR, 4.1; 95% CI, 1.4 to 11.8; P = .01). Fifteen of 34 asparaginase-rechallenged patients developed a second AAP. Asparaginase was truncated in 17/21 patients with AAP who subsequently developed leukemic relapse, but neither AAP nor the asparaginase truncation was associated with increased risk of relapse. CONCLUSION Older children and adults had similar AAP risk, whereas morbidity was most pronounced among adolescents. Asparaginase re-exposure should be considered only for patients with an anticipated high risk of leukemic relapse, because multiple studies strongly indicate that reduction of asparaginase treatment intensity increases the risk of relapse. (C) 2019 by American Society of Clinical OncologyPeer reviewe