New recommendations in the treatment of Gram-positive bacteraemia in dialysis patients

Abstract

There is a progressive increase in community and nosocomial infections caused by Gram-positive pathogens, which often result in bacteraemia resistant to antibiotics. Many Gram-positive bacteria, including coagulasenegative staphylococci, Staphylococcus aureus and enterococcus species, may colonize the skin, mucous membranes (particularly anterior nares) and lower bowel of most normal subjects. In general, these bacteria do not incur consequences to the host, as the intact cornified squamous epithelium can prevent their access to subcutaneous tissues and blood. Only when the skin or mucous membranes are disrupted, may staphylococci give rise to localized superficial abscesses. Cutaneous infections are often self-limited, because normal subjects can organize a primary defence based on neutrophils and opsonophagogytosis. Nevertheless, if bacteria invade the lymphatics and the blood, they can cause a number of life-threatening complications such as septic shock, endocarditis, pneumonia, osteomyelitis, etc. The leading pathogens are coagulase-negative staphylococci and S. aureus, followed by enterococcus species [1]. The coagulase-negative staphylococci such as Staphylococcus epidermidis have been considered as avirulent commensals in the past. However, in the last 30 years, they have been recognized to be one of the most frequent pathogens responsible for nosocomial infection, with a high rate of mortality. The development of bacteraemia is largely influenced by factors such as (i) the use of catheters that can disrupt the cutaneous barrier to Gram-positive pathogens; (ii) a heavy colonization at mucocutaneous sites, that is favoured by wounds, traumas, ulcers, etc; (iii) the virulence of the pathogen including its ability to produce enzymes