Pyogenic Liver Abcess in Guadeloupe

Overview

Liver abscesses are infections of the liver parenchyma, most often bacterial, occurring via the biliary tract, bloodstream, or by direct spread. Although rare, they are serious, with a mortality rate of around 15%. In Western countries, they are mainly polymicrobial or associated with Escherichia coli, streptococci, and Klebsiella pneumoniae. While overall incidence is low, it appears higher in Guadeloupe. There is a growing increase in cases caused by hypervirulent \*Klebsiella pneumoniae\* (hvKp), which can infect healthy individuals and spread to distant sites such as the eye, lungs, and central nervous system. Its virulence is linked to specific genetic factors. The emergence of multidrug-resistant hypervirulent strains represents a major concern. In Guadeloupe, about ten cases per year are reported, with no clearly identified risk factors.

Microbial contamination of the liver parenchyma leading to liver abscess (LA) can occur via the bile ducts or vessels (arterial or portal), or directly by contiguity. Infection is usually bacterial, sometimes parasitic, and very rarely fungal. In the Western world, bacterial (pyogenic) LA is the most prevalent; mortality remains high, approaching 15%, mainly due to patient debilitation and persistence of the underlying cause. Bacterial LA are mainly of polymicrobial origin (35% of cases) or associated with Escherichia coli (39% of cases); other etiologies include streptococci (36.5%) and Klebsiella pneumoniae (9.5%) in France. The incidence of LA is low, ranging from 8 to 22 cases per 1,000,000 individuals. In Guadeloupe, few data are available; however, the number of cases observed at the Centre University Hospital of Guadeloupe (CHUG) is approximately 30 to 40 per year, suggesting that Guadeloupe is an area of relatively high incidence. Currently, the incidence of LA associated with hypervirulent Klebsiella pneumoniae (hvKp) is increasing. hvKp is more virulent than classical K. pneumoniae (cKp) and causes community-acquired infections, often in otherwise healthy individuals. In addition to liver abscesses, hvKp is distinguished from cKp by its ability to metastasize to distant sites, most commonly the eye, lungs, and central nervous system. The genetic determinants of hypervirulence are often located on large virulence plasmids as well as chromosomal mobile genetic elements, which can be used as biomarkers to distinguish hvKp from cKp clinical isolates. These virulence determinants include multiple siderophore systems for iron acquisition, increased capsule production, K1 and K2 capsular types, and the colibactin toxin. Alarmingly, multidrug-resistant hypervirulent strains have emerged, creating a new challenge in managing this already dangerous pathogen. In Guadeloupe, approximately ten cases of LA associated with hvKp are reported at the CHUG each year, and most patients report no contact with Asia or individuals of Asian origin. Risk factors remain poorly understood.