Eight cases of invasive Klebsiella pneumoniae infection from a public teaching medical institution in the USA

Background: Klebsiella pneumoniae is a common human bacterial pathogen known to cause invasive infections such as primary liver abscesses, necrotizing fasciitis, meningitis and endophthalmitis with bacteraemia among patients in eastern Asia. Over the last decade, geographical spread and emergence of invasive K. pneumoniae infection has occurred in the USA. The majority of reported cases involve males with diabetes mellitus, of Asian ethnicity and who have recently travelled to Asia. Results: We identified eight invasive cases with liver abscesses and necrotizing fasciitis at our institution. The most common risk factors associated with invasive infection were male gender and diabetes mellitus, which is consistent with other reported cases. However, Caucasians and Hispanics represented the majority of invasive disease (n57), and history of recent travel to Asia was not identified in any of the cases. Discussion: Further studies with larger cohorts involving multiple healthcare institutions in the USA are warranted to confirm these two unusual characteristics of infection. Healthcare professionals should be informed of the possible association between K. pneumoniae and invasive disease in male diabetic persons of non-Asian descent and without recent travel to Asia in the USA.