Background
The selection pressure exercised by antibiotic drugs is an important consideration for the wise stewardship of antimicrobial treatment programs. Treatment decisions are currently based on crude assumptions, and there is an urgent need to develop a more quantitative knowledge base that can enable predictions of the impact of individual antibiotics on the human gut microbiome and resistome.
Results
Using shotgun metagenomics, we quantified changes in the gut microbiome in two cohorts of hematological patients receiving prophylactic antibiotics; one cohort was treated with ciprofloxacin in a hospital in Tübingen and the other with cotrimoxazole in a hospital in Cologne. Analyzing this rich longitudinal dataset, we found that gut microbiome diversity was reduced in both treatment cohorts to a similar extent, while effects on the gut resistome differed. We observed a sharp increase in the relative abundance of sulfonamide antibiotic resistance genes (ARGs) by 148.1% per cumulative defined daily dose of cotrimoxazole in the Cologne cohort, but not in the Tübingen cohort treated with ciprofloxacin. Through multivariate modeling, we found that factors such as individual baseline microbiome, resistome, and plasmid diversity; liver/kidney function; and concurrent medication, especially virostatic agents, influence resistome alterations. Strikingly, we observed different effects on the plasmidome in the two treatment groups. There was a substantial increase in the abundance of ARG-carrying plasmids in the cohort treated with cotrimoxazole, but not in the cohort treated with ciprofloxacin, indicating that cotrimoxazole might contribute more efficiently to the spread of resistance.
Conclusions
Our study represents a step forward in developing the capability to predict the effect of individual antimicrobials on the human microbiome and resistome. Our results indicate that to achieve this, integration of the individual baseline microbiome, resistome, and mobilome status as well as additional individual patient factors will be required. Such personalized predictions may in the future increase patient safety and reduce the spread of resistance.
Trial registration
ClinicalTrials.gov, NCT02058888. Registered February 10 2014
Reduced anticancer efficacy of cyclophosphamide and platinum salts has been reported in animals treated with anti-Gram-positive antibiotics. These effects were related to translocation of Gram-positive bacteria during mucositis with subsequent induction of cytotoxic oxygen reactive species and tumor invasion by pathogenic Th17 cells. To assess these hypotheses in a clinical setting, we identified patients receiving cyclophosphamide for chronic lymphocytic leukemia (CLL) and cisplatin for relapsed lymphoma. Data originated from the CLL8 trial (NCT00281918) and the Cologne Cohort of Neutropenic Patients (NCT01821456). Relevant antibiotics were defined as compounds with primary activity against Grampositive bacteria. We evaluated their impact on response, progression-free survival (PFS) and overall
Reactivation of viral infections is common in patients with solid tumour or haematological malignancy. Incidence and severity depend on the extent of cellular immunosuppression. Antiviral prophylaxis may be effective to prevent viral reactivation. In 2006, the Infectious Diseases Working Party of German Society for Hematology and Medical Oncology (DGHO) published guidelines for antiviral prophylaxis in these patient populations. Here, we present an update of these guidelines for patients with solid and haematological malignancies undergoing antineoplastic treatment but not allogeneic stem cell transplantation. Relevant literature for reactivation of different viruses (herpes simplex virus (HSV), varicella zoster virus (VZV), hepatitis B virus (HBV) and respiratory viruses) is discussed to provide evidence-based recommendations for clinicians taking care of this patient population. We recommend a risk-adapted approach with (val)acyclovir against HSV and VZV in patients treated with alemtuzumab, bortezomib or purine analogues. Seasonal vaccination against influenza is recommended for all patients with solid or haematological malignancies regardless of antineoplastic therapy. Hepatitis B screening is recommended in lymphoproliferative disorders, acute leukaemia, and breast cancer, and during treatment with monoclonal anti-B-cell antibodies, anthracyclines, steroids and in autologous stem cell transplantation. In those with a history of hepatitis B prophylactic lamivudine, entecavir or nucleotide analogues as adefovir are recommended to prevent reactivation.
Patients receiving treatment for acute myelogenous leukemia (AML) and recipients of allogeneic stem cell transplantation (aSCT) are at high risk of contracting Clostridium difficile infection (CDI), the most frequently observed nosocomial diarrhea and enterocolitis. Data were retrieved from the prospective Cologne Cohort of Neutropenic Patients. Patients hospitalized for aSCT as well as patients receiving treatment for AML were included in the analysis. Risk factor analysis for the occurrence of CDI was performed by backward-stepwise logistic regression (P < .1). During the period from January 2007 to August 2010, 310 hospitalizations of 152 patients with AML and 229 hospitalizations of 223 patients undergoing aSCT were eligible for analysis. Incidence rates for CDI per 10,000 patient days were 17.9 for AML patients and 27.4 for aSCT recipients. Among AML and aSCT patients, median time from initiation of chemotherapy to CDI was 10 days (range, -8 to 101 days) and 17 days (range, 6 to 79), respectively. Logistic regression identified carbapenem exposure to be associated with development of CDI in AML patients (odds ratio [OR], 2.2) and aSCT recipients (OR, 1.4). In both groups, previous exposure to carbapenems was significantly associated with development of CDI. A follow-up study, assessing the effect of an antibiotic stewardship intervention to decrease the administration of carbapenems in hematological high-risk patients, is warranted.
Rates of bIFIs observed in our population were comparable to previous data. There was no clear shift towards rare species, as previously reported. A high variety of treatment approaches was observed.
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