Carbapenemase-producing Enterobacteriaceae circulating in the Reunion Island, a French territory in the Southwest Indian Ocean

Abstract

Background: The spread of carbapenemase-producing Enterobacteriaceae (CPE) in the Southwest Indian Ocean area (SIOA) is poorly documented. Reunion Island is a French overseas territory located close to Madagascar and connected with Southern Africa, Indian sub-continent and Europe, with several weekly flights. Here we report the results of the CPE surveillance program in Reunion Island over a six-year period.

Methods: All CPE were collected between January 2011 and December 2016. Demographics and clinical data of the carrier patients were collected. We determined their susceptibility to antimicrobials, identified the carbapenemases and ESBL by PCR and sequencing, and explored their genetic relationship using pulsed-field gel electrophoresis and multi-locus sequence typing.

Results: A total of 61 CPEs isolated from 53 patients were retrieved in 6 public or private laboratories of the island. We found that 69.8% of CPE patients were linked to a foreign country of SIOA and that almost half of CPE cases (47.2%) reached the island through a medical evacuation. The annual number of CPE cases strongly increased over the studied period (one case in 2011 vs. 21 cases in 2016). A proportion of 17.5% of CPE isolates were non-susceptible to colistin. bla_NDM was the most frequent carbapenemase (79.4%), followed by bla_IMI (11.1%), and bla_IMP-10 (4.8%). Autochtonous CPE cases (30.2%) harboured CPE isolates belonging to a polyclonal population.

Conclusions: Because the hospital of Reunion Island is the only reference healthcare setting of the SIOA, we can reasonably estimate that its CPE epidemiology reflects that of this area. Mauritius was the main provider of foreign CPE cases (35.5%). We also showed that autochthonous isolates of CPEs are mostly polyclonal, thus unrelated to cross-transmission. This demonstrates the local spread of carbapenemase-encoding genes (i.e. bla_NDM) in a polyclonal bacterial population and raises fears that Reunion Island could contribute to the influx of NDM-carbapenemase producers into the French mainland territory.

Keywords: Carbapenemase; Epidemiology; French overseas territory; Indian Ocean; NDM; Reunion Island.

Fig. 1

Number of patients with carbapenemase-producing Enterobacteriaceae (CPE) detected between 2011 and 2016 in Reunion Island (France). The number of CPE cases linked and not with a foreign country is represented by the black and grey bars, respectively. The upward trends in the ‘total’ [p < 0.001], ‘linked with a foreign country’ [p < 0.001]’ and ‘not linked with a foreign country’ [p = 0.006]’ CPE incidence rates (case per patient-days) were significant

Fig. 2

Molecular genotyping (PFGE and MLST analysis) applied to 57 CPE isolates of K. pneumoniae, E. coli, E. cloacae, C. freundii, and S. marcescens (2011–2016, Reunion Island, France). There is not MLST scheme definition for S. marcescens. Data presented: PFGE pattern, bacterial species (KPNE, K. pneumoniae; ECOL, E. coli; ECLO, E. cloacae; CFRE, C. freundii, SMAR, S. marcescens), sequence type, clonal complex, carbapenemase(s) produced, foreign country visited by the patient within the year before CPE isolation, month and year of CPE isolation. The similarity scales are specific of each bacterial species. The optimization and band-tolerance values used for PFGE dendrogram were 1%