Serratia Infections: from Military Experiments to Current Practice

<jats:title>SUMMARY</jats:title><jats:p><jats:named-content content-type="genus-species">Serratia</jats:named-content>species, in particular<jats:named-content content-type="genus-species">Serratia marcescens</jats:named-content>, are significant human pathogens.<jats:named-content content-type="genus-species">S. marcescens</jats:named-content>has a long and interesting taxonomic, medical experimentation, military experimentation, and human clinical infection history. The organisms in this genus, particularly<jats:named-content content-type="genus-species">S. marcescens</jats:named-content>, were long thought to be nonpathogenic. Because<jats:named-content content-type="genus-species">S. marcescens</jats:named-content>was thought to be a nonpathogen and is usually red pigmented, the U.S. military conducted experiments that attempted to ascertain the spread of this organism released over large areas. In the process, members of both the public and the military were exposed to<jats:named-content content-type="genus-species">S. marcescens</jats:named-content>, and this was uncovered by the press in the 1970s, leading to U.S. congressional hearings.<jats:named-content content-type="genus-species">S. marcescens</jats:named-content>was found to be a certain human pathogen by the mid-1960s.<jats:named-content content-type="genus-species">S. marcescens</jats:named-content>and<jats:named-content content-type="genus-species">S. liquefaciens</jats:named-content>have been isolated as causative agents of numerous outbreaks and opportunistic infections, and the association of these organisms with point sources such as medical devices and various solutions given to hospitalized patients is striking.<jats:named-content content-type="genus-species">Serratia</jats:named-content>species appear to be common environmental organisms, and this helps to explain the large number of nosocomial infections due to these bacteria. Since many nosocomial infections are caused by multiply antibiotic-resistant strains of<jats:named-content content-type="genus-species">S. marcescens</jats:named-content>, this increases the danger to hospitalized patients, and hospital personnel should be vigilant in preventing nosocomial outbreaks due to this organism.<jats:named-content content-type="genus-species">S. marcescens</jats:named-content>, and probably other species in the genus, carries several antibiotic resistance determinants and is also capable of acquiring resistance genes.<jats:named-content content-type="genus-species">S. marcescens</jats:named-content>and<jats:named-content content-type="genus-species">S. liquefaciens</jats:named-content>are usually identified well in the clinical laboratory, but the other species are rare enough that laboratory technologists may not recognize them. 16S rRNA gene sequencing may enable better identification of some of the less common<jats:named-content content-type="genus-species">Serratia</jats:named-content>species.</jats:p>