Community-acquired Klebsiella pneumoniae liver abscess: the London experience.

We read with interest the case series and review of Klebsiella pneumoniae community-acquired liver abscesses in Ireland and Europe by Moore and colleagues [1]. While we would agree that K. pneumoniae is a significant microbiological cause of this disease, we question the incidence of K. pneumoniae bacteremia which results in communityacquired liver abscesses, and also whether K. pneumoniae or the Streptococcus anginosus group remain more commonly associated with this condition in the United Kingdom. Our area of practice encompasses a multi-site NHS Hospital Trust with three tertiary referral hospitals and a second NHS Trust with a single tertiary referral hospital, both in north-west London. These four hospitals accept acute adult admissions and provide services to a population approximating two million. We reviewed both positive K. pneumoniae and S. anginosus group bacteremias and also solicited consults to Clinical Infectious Diseases services relating to community-acquired liver abscesses. Amongst patients over 18 years of age, we found 207 K. pneumoniae bacteraemias over a 4 year period from 2009 to 2012 from the four tertiary referral hospitals. Of these, 162 had contemporaneous abdominal imaging with either ultrasonography or computerised tomography. Within those 162 cases, only 13 (8.0 %) had evidence of a liver abscess. Over the same period, we found 35 S. anginosus group bacteremias, of whom 27 had concomitant abdominal imaging with either ultrasonography or computerised tomography. While a numerically smaller cohort, we found six (22 %) confirmed community-acquired liver abscesses in this group, a rate almost three times that in our K. pneumoniae bacteremias. In the patients with S. anginosus group liver abscesses, imaging confirmed extrahepatic metastatic spread in all six of these patients, but only one of the 13 K. pneumoniae liver abscess patients. In the same north-west London cohort, Clinical Infectious Diseases services are offered and electronically recorded in two of these hospitals. Over the same period, from 2719 solicited consults we found a further 12 cases of community acquired liver abscesses, of which a causative organism was identified in 11. While K. pneumoniae was the causative pathogen in two cases, we found S. anginosus group a more frequent mono-microbial cause, being isolated in five patients. The remaining cases had Enterobacter cloacae (one case) or Escherichia coli (one case) isolated, or positive amoebic serology (two cases). Our case series of 15 K. pneumoniae communityacquired liver abscesses was reviewed—13 from bacteremic patients, two cases from Clinical Infectious Diseases consults (Table 1). Of these 15, we found that 13 were male, six had a diagnosis of diabetes mellitus and six had a history of travel to Asia, Africa or the Pacific region within the last 6 months. We found a mean age of 58 years. Fever was ubiquitous in their presentation, and eight of the 15 had abdominal pain as part of their symptomatology. This epidemiological data broadly supports that identified by Moore and colleagues, but in L. S. P. Moore (&) National Centre for Infection Prevention and Management, Imperial College London, Du Cane Road, London W12 0HS, UK e-mail: 1.moore@imperial.ac.uk