Sterile site infection at autopsy in sudden unexpected deaths in infancy

Objective: To examine and compare bacteriological findings at autopsy of cases of sudden unexpected infant death and those of deaths from other cause. Design: Autopsy report review of 130 sudden infant death syndrome (SIDS) cases (2004 definition), 32 cases of sudden unexpected death in infancy (SUDI) due to infection and 33 cases of non-infectious sudden deaths. Setting: Qualitative assessment of normally sterile site (NSS; heart blood, spleen or cerebrospinal fluid) bacteriology in SIDS and age-matched comparison deaths that occurred in the late 1980s and early 1990s. Main outcome measures: Comparative sterile site bacteriological findings. Results: Sterile site infection was rare in cases of sudden accidental death (eg, motor vehicle accident or drowning); however, the finding of true pathogens such as Staphylococcus aureus in sterile sites in SIDS and deaths associated with infection was relatively common. 10.76% of SIDS had S aureus present in a sterile site, compared with 18.75% of cases of infection-related deaths. S aureus was not found in sudden accidental deaths. The incidence of coliform bacteria in NSS in SIDS was not significantly different from that seen in deaths from other cause. NSS bacteriology yielded no growth in 45.4% of sudden accidental deaths, 43% of SIDS and 28.1% of infectious causes of death. Conclusions: The finding of S aureus in NSS in a large proportion of cases of SIDS would indicate that a proportion of these babies died of staphylococcal disease. Although the differences in NSS isolation of S aureus in the three infant groups did not quite achieve significance, on the basis of these findings and the characteristic virulence of S aureus, it is recommended that sudden unexpected deaths from which S aureus is isolated from NSS be considered for reclassification. The incidence of coliform bacteria in NSS in SIDS is not significantly different from that in deaths from another cause (both accidental and infectious). From these findings it is recommended that the opinion of a consultant microbiologist be sought to interpret microbiological findings prior to finalising autopsy reports on SUDI.