Pathogens in severe sepsis: New paradigms for gram-positive treatment

Severe sepsis has become the preeminent infection within hospitals and intensive care units. Among the pathogens associated with severe sepsis, gram-positive bacteria, particularly methicillin-resistant Staphylococcus aureus (MRSA), have become the most common cause of healthcare-associated severe sepsis. MRSA is also an important cause of severe sepsis because it displays a remarkable array of resistance and virulence factors, which have contributed to its prominent role in infections of the critically ill. It is important that clinicians recognize the changing resistance patterns and epidemiology of MRSA, as well as other gram-positive pathogens, as these factors may impact patient outcomes. Given the paramount importance of MRSA as a nosocomial pathogen, we will focus this review on a discussion of MRSA and its treatment. When initiating empiric antibiotics, it is of vital importance that this therapy be timely and appropriate, as delays in treatment are associated with adverse outcomes. However, the use of older therapies for MRSA, such as vancomycin, has important limitations that will require a re-thinking as to the best approach for the treatment of MRSA infections. This will also require the recognition that therapies may have to vary depending on the type of MRSA infection the clinician is faced with (e.g., pneumonia, bacteremia, skin and skin structure).