Finally, criteria of severe sepsis at the onset, such as cutaneous hypoperfusion, organ dysfunction, hypotension (systolic arterial pressure <90mmHg decreasing >40mmHg from basal value) or lactic acidosis, require the addition of both glycopeptide and aminoglycoside antibiotics. Subsequent treatment will depend on several considerations:

• In the absence of clinical or microbiological documentation, glycopeptide and/or aminoglycoside antibiotics should be discontinued if previously given.

• If microbiological documentation is achieved, therapy should be adapted accordingly. Antibiotic changes should not rely only on the persistence of fever. Clinical data should be considered.

• Appropriate duration is not defined. In the setting of severe clinically and/or microbiologically documented infection, antibiotic therapy should be maintained for a minimum of 12 to 14 days.

• If fever persists, non-infectious causes and the possibility of stopping antibiotic therapy should be considered, as well as for possible atypical infections.

The algorithm for empirical management of highrisk FN is outlined in Figure 2. However, some patients with solid tumour, lymphoma or myeloma treated with chemotherapy regimens producing neutropenia of intermediate duration (seven to 14 days) exhibit a rapid response to the initial antibiotic therapy. In such patients, it would be advisable to administer hospital-based, shortduration IV treatment and subsequent oral therapy at home (sequential therapy).

The practice of antimicrobial prophylaxis has been questioned repeatedly. Although oral prophylaxis against bacterial and fungal infections may decrease the risk of development of infections after bone marrow transplantation or chemotherapy, these practices also promote the emergence of drugresistant strains (particularly fluoroquinoloneresistant Escherichia coli and fluconazole-resistant non-albicans Candida species). The use of fluoroquinolones for prophylaxis in high-risk patients with neutropenia has been also associated with the emergence of resistance among Pseudomonas aeruginosa isolates (more than 20% at some institutions). The 2002 guidelines from the Infectious Diseases Society of America (IDSA) did not recommend the routine fluoroquinolone prophylaxis during neutropenia. However, this may be considered for high-risk patients in critical periods of time.

In conclusion, a rapid detection of trends in antibiotic resistance patterns of predominant organisms at each institution is of paramount importance for optimal antibiotic selection.