Multidrug-resistant bacteria: what is the threat?

Despite big advances in antimicrobial therapies and infection strategies, the emergence of antibiotic resistance represents an emergency situation, especially in immunocompromised hosts. Specifically, infections due to multidrug resistant, gram-negative pathogens are responsible for high mortality rates and may leave few effective antimicrobial options. Furthermore, although new compounds are available for severe methicillin-resistant staphylococcal infections, there is a paucity of novel classes of antimicrobials to target resistant gram-negatives. A careful assessment of the clinical conditions and underlying comorbidities, along with knowledge about the previous history of colonization or infections due to multidrug-resistant bacteria, represent key points in approaching the hematological patient with signs of infection. A de-escalation therapy with initial use of wide-spectrum antimicrobials followed by a reassessment after 72 hours of treatment may represent a good option in severe infections if a resistant pathogen is suspected. Prompt empiric or targeted therapy using combination regimens (ie, antipseudomonal beta-lactam plus an aminoglycoside or a quinolone) with the addition of colistin, along with increased dosage and therapeutic drug monitoring, represent options for these life-threatening infections. Continuous epidemiological surveillance of local bacteremias is necessary, along with stringent enforcement of antibiotic stewardship programs in cancer patients.