Molecular characterization of multidrug-resistant extended-spectrum β-lactamase-producing Enterobacteriaceae isolated in Antananarivo, Madagascar.

Hanitra C Rakotonirina (1, 2) , Benoît Garin (1) , Frédérique Randrianirina (1) , Vincent Richard (1, 3) , Antoine Talarmin (1, 4) , Guillaume Arlet (5, 6)

1 Institut Pasteur de Madagascar
2 Laboratoire de Bactériologie, Faculté de médecine
3 Institut Pasteur de Dakar
4 Institut Pasteur de la Guadeloupe
5 UMRS893 - Centre de Recherche Saint-Antoine
6 CHU Tenon [AP-HP]

BACKGROUND: We investigated the molecular characteristics of multidrug-resistant, extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae isolated in community settings and in hospitals in Antananarivo, Madagascar. RESULTS: Forty-nine E. coli, K. pneumoniae, K. oxytoca and E. cloacae ESBL-producing isolates were studied. In antimicrobial susceptibility analyses, many of the isolates exhibited resistance to aminoglycosides, fluoroquinolones and trimethoprim-sulfamethoxazole. Gene amplification analysis and sequencing revealed that 75.5% (n=37) of the isolates harbored blaCTX-M-15 and 38.7% (n=19) harbored blaSHV-12. The non-ESBLs resistance genes detected were blaTEM-1, blaOXA-1, aac(6')-Ib,aac(6')-Ib-cr, tetA, sul-1, sul-2, qnrA, qnrB and catB-3. We found dfrA and aadA gene cassettes in the class 1 integron variable regions of the isolates, and the combination of dfrA17-aadA5 to be the most prevalent. All blaCTX-M-15 positive isolates also contained the ISEcp1 insertion element. Conjugation and transformation experiments indicated that 70.3% of the antibiotic resistance genes resided on plasmids. Through a PCR based replicon typing method, plasmids carrying the blaSHV-12 or blaCTX-M-15 genes were assigned to either the IncFII replicon type or, rarely, to the HI2 replicon type. All isolates were subtyped by the rep-PCR and ERIC-PCR methods.Phylogenetic grouping and virulence genotyping of the E. coli isolates revealed that most of them belonged to group A1. One isolate assigned to group B2 harbored blaCTX-M-15 and five virulence genes (traT, fyuA, iutA, iha and sfa) and was related to the O25b-ST131 clone. CONCLUSIONS: Our results highlight the dissemination of multidrug resistant Enterobacteriaceae isolates in Antananarivo. These findings underline the need for a rational use of antibiotic and for appropriate methods of screening ESBL in routine laboratories in Antananarivo.

Domaines: Sciences du Vivant [q-bio]

Hanitra C Rakotonirina, Benoît Garin, Frédérique Randrianirina, Vincent Richard, Antoine Talarmin, et al.. Molecular characterization of multidrug-resistant extended-spectrum β-lactamase-producing Enterobacteriaceae isolated in Antananarivo, Madagascar.. BMC Microbiology, 2013, 13, pp.85. ⟨10.1186/1471-2180-13-85⟩. ⟨pasteur-00835131⟩