Trends among pathogens reported as causing bacteraemia in England, 2004-2008.

The Health Protection Agency in England operates a voluntary surveillance system that collects data on bacteraemias reported by over 90% of laboratories in England. Trends in causative microorganisms reported between 2004 and 2008 were analyzed using a generalized linear model with a log link function for Poisson distribution. In 2008, 101,276 episodes of bacteraemia were reported; a rate of 189 per 100,000 population. More than one-half occurred in those aged over 65 years and males. The most common organisms reported were Escherichia coli (23%), coagulase-negative staphylococci (CNS) (16.9%) and Staphylococcus aureus (11.4%). Between 2004 and 2008, E. coli bacteraemia increased by 33% (p < 0.001); the species now accounts for more than 30% of bacteraemia in those aged over 75 years. There also were significant increases in bacteraemia caused by other Gram-negative pathogens and marked seasonal variation. Bacteraemia caused by S. aureus increased until 2005, with a decline after 2006 (p < 0.001) entirely due to methicillin-resistant strains. CNS bacteraemia have declined significantly since 2007. The renewed dominance of Gram-negative pathogens as major causes of bacteraemia in England is of particular concern because they are associated with a high morbidity and increasing resistance to antibiotics. Further investigation of the underlying causes and prevention strategies is a public health priority. Recent declines in methicillin-resistant S. aureus bacteraemia have not been reflected in other pathogens, including methicillin-susceptible S. aureus.