Invasive Klebsiella pneumoniae Infections, California | CDC EID

EID Journal Home > Volume 16, Number 9–September 2010

Volume 16, Number 9–September 2010
Letter
Invasive Klebsiella pneumoniae Infections, California, USA
Robert McCabe, Larry Lambert, and Brad Frazee
Author affiliations: Alameda County Medical Center, Oakland, California, USA (R. McCabe, L. Lambert, B. Frazee); and St. Rose Hospital, Hayward, California, USA (R. McCabe)

To the Editor: A distinctive form of tissue-invasive community-associated Klebsiella pneumoniae infection, typified by primary liver abscess and bacteremia, has been well known in Asia for 2 decades (1–4). Association of these infections with a hypermucoviscous phenotype was discovered in 2004 (5). Certain genetic and virulence features were elucidated in that and subsequent reports (6).

The phenotype, easily detected at the bench by the string test (5), has been associated with a chromosomal gene, the mucoviscosity-associated gene A (magA), and a plasmid gene, the regulator of the mucoid phenotype A gene (rmpA). Usually serotypes K1 and K2 can be demonstrated. Hypermucoviscous isolates demonstrate increased virulence in mice, are serum insensitive, and resist phagocytosis (5).

Reports of such infections from Europe and North America are rare. Recently 2 of us (L.L and B.F.) reported 4 cases in persons seeking care at the Alameda County Medical Center in Oakland, California, USA (7). We report 9 more cases, 7 from Alameda County Medical Center and 2 from St. Rose Hospital in Alameda County. The 13 cases are described in aggregate.

One case occurred in 2006, 3 in 2007, 7 in 2008, and 2 in January 2009. Median patient age was 52 years (range 37–70 years), and 9 were men. Ten patients were born in Asia (Philippines, Vietnam, South Korea, Cambodia, and Yemen), but all had emigrated years earlier. Two patients were born in the United States (1 Filipino and 1 African American); the birth site of 1 Filipino was unknown. Five patients had no underlying illness. Seven had diabetes mellitus, 1 had α-thalassemia, 2 had uncontrolled cancer, and 1 had preexisting multiple organ failure. Three patients had gallstones.



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