Nosocomial Outbreaks Caused by Leuconostoc mesenteroides
From July 2003 through October 2004, 42 patients became infected by strains of Leuconostoc mesenteroides subsp. mesenteroides (genotype 1) in different departments of Juan Canalejo Hospital in northwest Spain. During 2006, 6 inpatients, also in different departments of the hospital, became infected (genotypes 2-4). Parenteral nutrition was the likely source.

Leuconostoc species are catalase-negative, gram-positive microorganisms with coccoid morphology. In 1985, Buu-Hoi et al. reported the first cases of Leuconostoc infection in humans. Since then, Leuconostoc spp. have been implicated in a variety of infections, particularly in patients being treated with vancomycin and in immunocompromised patients. However, these species have never previously been considered as agents that cause severe hospital outbreaks that threaten the lives of large numbers of persons.

Between July 2003 and October 2004, and between August and November 2006, 42 and 6 patients, respectively (Figure 1), in the Juan Canalejo Hospital (a tertiary-level, 1,400-bed hospital serving a population of 516,000 in La Coruña, northwest Spain) became infected by a strain of Leuconostoc mesenteroides subsp. mesenteroides (LM). The patients had been admitted to 13 different, physically separated departments in the hospital (3 different hospital buildings), and 11 of the 48 were newborns. The aims of the present study were to characterize the epidemiologic features of the outbreak and to determine the risk factors associated with the infection.



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Epidemic curve of distribution of Leuconostoc-infected patients throughout the period of study.