Transmission of IMI-2 carbapenemase-producing Enterobacteriaceae from river water to human.

OBJECTIVES: Carbapenemase-producing Enterobacteriaceae (CPE) are increasing worldwide in human infections. The role of rivers as reservoirs is highlighted, but transmission from the environment to humans is not documented. A human case of bacteraemia caused by IMI-2 carbapenemase-producing Enterobacter asburiae following massive river water exposure underwent microbiological investigations with the aim of deciphering the origin and mechanism of infection. METHODS: Clinical and environmental bacterial strains were compared by resistotyping and genomotyping using pulsed-field gel electrophoresis (PFGE). PFGE was also used to determine the location of the blaIMI-2 carbapenemase gene. The patient's microbiota and river bacterial communities were compared by fingerprinting using 16S rRNA gene PCR-temporal temperature gel electrophoresis. RESULTS: Enterobacter asburiae causing bacteraemia carried the same plasmidic blaIMI-2 gene as E. asburiae strains detected in river water 1 month later. Clinical and river strains displayed identical PFGE profiles. Community fingerprinting showed the persistence in the patient's microbiota of carbapenem-resistant bacteria, which were also autochthonous in the river community (E. asburiae, Aeromonas veronii and Pseudomonas fluorescens). CONCLUSION: Here we have identified for the first time the presence of an IMI-2-producing E. asburiae in a river in the South of France and suggest transmission from the river to a human probably following intestinal translocation. General insights into transmission of CPE from the environment to humans are gained from this case. Considering the rapid spread of CPE in humans, the risk of transfer from an environmental reservoir to human microbiota should be thoroughly investigated at least by implementing environmental surveillance of carbapenem resistance.

tuf-PCR-temporal temperature gradient gel electrophoresis for molecular detection and identification of staphylococci: application to breast milk and neonate gut microbiota.

Coagulase negative staphylococci (CoNS) are a leading cause of infections in preterm infants, mostly involved in late-onset infection in low birth weight neonates. The epidemiology and pathophysiology of these infections remain unclear, notably because the causing agents are gathered in the artificial CoNS group. The aim of this work was to optimize the study of Staphylococcus species diversity in human breast milk and neonate stool, two sample types with bacterial communities dominated by CoNS, using PCR-temporal temperature gel electrophoresis based on the tuf gene. The optimized protocol identified 18 Staphylococcus species involved in neonate gut microbiota and infections and was applied to cultivation-independent study of breast milk and neonate stool. The efficiency, sensitivity, specificity and species discrimination of the proposed protocol appears suitable for patient follow-up in order to link microbiological data at the community level in milk and stool and interpret them from epidemiological and pathophysiological points of view.