A Prospective, Multicenter Survey of Severe Infections by Gram Negative Bacteria in Patients Submitted to Autologous and Allogeneic Stem Cell Transplant.

Severe Infections by Gram Negative Bacteria (SIGNB) remain an important cause of morbidity and mortality in patients submitted to stem cell transplant particularly during engraftment while patients suffer of profound and prolonged neutropenia or during subsequent neutropenia periods related to loss of engraftment or viral infections. Epidemiology of severe infections by gram negative bacteria in stem cell transplant patients has varied in the last decades due to the increasing use of highly immunosuppressive stem cell transplant procedures, and in relation to global epidemiological phenomena involving several populations of immunocompromised patients including those submitted to stem cell transplant.

The epidemiological evolution of severe infections by gram negative bacteria in immunocompromised patients is represented also by the emergence of infections caused by Gram-negative bacilli, in particular enterobacteria, resistant to several antimicrobials. Such pattern of susceptibility to antibacterial agents represents a challenging issue in the currents strategies of the use of antibiotics in prophylaxis or therapy.

Despite an increasing attention to the clinical and therapeutic aspects of infection in stem cell transplant recipients, contrasting data are available on the incidence, microbiologic characteristics and clinical outcome of Severe Infections by Gram Negative Bacteria in this population.

Management of patients submitted to stem cell transplant is frequently complicated by Severe Infections by Gram Negative Bacteria which may represent an obstacle to the transplant procedure. Severe Infections by Gram Negative Bacteria caused by microorganisms resistant to betalactamic antibiotics, which are the golden standard in the empirical antibacterial therapy of febrile neutropenia, represent a challenging problem. A revision of the antibacterial strategies and the consideration of new molecules with different antibacterial mechanism of action should be considered in the light of the emerging epidemiology. Antimicrobial prophylaxis, diagnostic approaches and antimicrobial therapy should be adapted to the infectious risk of the transplant population according to stem cell source, conditioning regimen and also to the infectious history before transplant. A crucial problem in the definition of these strategies is represented by the continuous change in the epidemiological patterns of infections as a result of the modification of risk factors in the transplant population and of the global epidemiology of hospital and community acquired infections. In particular the emergence of antibiotic resistant enterobacteria represents a serious problem which dramatically impacts on the antibacterial prophylaxis and treatments choices.

The Investigator think that a continuous epidemiology survey is required in order to better define proper prevention, diagnostic and treatment approaches. A common problem in the infections control in immunocompromised populations is represented by the lack of epidemiological consciousness in the single centres and its relationship with the local policy in the use of antibacterial drugs. A prospective, multicenter survey of Severe Infections by Gram Negative Bacteria by antibiotic resistant pathogens, in particular enterobacteria, may be a useful tool to evaluate the epidemiological patterns of infections, their impact on the overall survival, and a critical analysis of the use of antibacterial drugs.