Emergence of NDM-1-producing Acinetobacter baumannii in Belgium.

Sir, New Delhi metallo-b-lactamase (NDM) is a class B b-lactamase that confers resistance to virtually all b-lactams, including carbapenems. Initially reported in Sweden in Enterobacteriaceae isolates from a patient transferred from India, NDM-1 is currently spreading worldwide, including Belgium, especially in Enterobacteriaceae. Recently the presence of blaNDM-1 was also reported in Acinetobacter baumannii isolates from India, China and Germany, suggesting a broad host range distribution of this gene. – 4 Here, we report an NDM-1-producing A. baumannii detected in Belgium that was isolated from a patient following medical repatriation from Algeria. In early 2011, a young male patient was admitted to the emergency ward of an Algerian hospital for severe cranial and thoracic trauma following a road traffic accident. He presented with a Glasgow Coma Score (GCS) of 07/15 and was rapidly intubated, ventilated and transferred to the intensive care unit (ICU). While hospitalized in Algeria, he experienced three successive, distinct episodes of bloodstream infection, due to Acinetobacter spp. , Candida albicans and Klebsiella pneumoniae, but no clinical information was available concerning the possible sources of these infections. In August, the patient was transferred, in a vegetative state (GCS of 02/15), to the ICU of a Belgian hospital. He was immediately placed in a single room with contact isolation precautions. Screening for asymptomatic intestinal carriage of carbapenemase producers was carried out upon admission, by rectal swabbing cultured by direct plating on ChromIDTM ESBL Agar (bioMérieux, Marcy l’Étoile, France). The recovered isolate was identified as A. baumannii (Ab 11314) by MicroFlex LT (Bruker Daltonik, Bremen, Germany). By disc diffusion, Ab 11314 was found to be multiresistant and synergy was observed in a double disc test using imipenem and EDTA (420 mg), suggesting involvement of a metallo-b-lactamase in resistance to b-lactams. Use of the CLSI microdilution method confirmed that the isolate was resistant to b-lactams including ceftazidime (MIC .64 mg/L), cefepime (MIC .64 mg/L), imipenem (MIC 4 mg/L; Etest MIC .32 mg/L), meropenem (MIC 4 mg/L; Etest MIC .32 mg/L), amikacin (MIC .32 mg/L) and ciprofloxacin (MIC .32 mg/L), and susceptible to tigecycline (MIC 0.125 mg/L), colistin (MIC 0.5 mg/L) and minocycline (MIC ,2 mg/L). Analysis of b-lactamase-coding genes by an MDR CT102 array (Check-Points, Wageningen, The Netherlands) and by PCR sequencing targeting metallo-b-lactamases and OXAcarbapenemases revealed the presence of blaNDM-1. Plasmid extraction was performed with a Qiagen plasmid kit, and this revealed a single 174 kb untypeable plasmid. This plasmid was efficiently electroporated and transferred by mating experiments to the A. baumannii recipient strain N9040364, and it conferred resistance to aminoglycosides (gentamicin, tobramycin and amikacin) only (data not shown). The blaNDM-1 gene was not associated with this plasmid suggesting that it was located in the chromosome. PCR mapping and sequencing revealed that blaNDM-1 was located between two direct repeats of the ISAba125 element in a transposon similar to the one in A. baumannii Ab 161/07 reported from Germany (accession no. HQ857107). Nevertheless, a PCR experiment performed with Ab 161/07 as a positive control revealed that in Ab 11314, in contrast, the mfs gene (a shikimate-transporter-coding gene belonging to the major facilitator superfamily) was not disrupted, indicating that the ISAba125 transposon was inserted elsewhere in the chromosome. By multilocus sequence typing (MLST) (http:// pubmlst.org/abaumannii/), A. baumannii Ab 11314 was shown to belong to sequence type (ST) 92 (allelic profile: 1-3-3-2-2-7-3), the founding genotype of clonal complex (CC) 92, which includes European clone 2 (EU2) and worldwide lineage 2 (WW2). CC92 is one of the most prevalent CCs worldwide, mostly represented by OXA-23-producing strains. Sequencing analysis of the intrinsic blaOXA-51-like and blaADC genes showed that this strain harboured blaOXA-64 and blaADC-26, neither of which was downstream of ISAba1 or ISAba125. These two intrinsic genes were identical to those recovered in the NDM-1-expressing A. baumannii Ab 161/07, but nevertheless presented a very different MLST profile (1-15-2-28-1-new allele-32), not related to any CC described up to now. This clinical isolate is the first characterized NDM-1-producing A. baumannii from Belgium. As yet, there have been only a few reports of NDM-producing A. baumannii, and the only case reported in Europe was from Germany in a patient transferred from Serbia in 2007. In the present case, the NDM-1-producing A. baumannii isolate originated from North Africa (Algeria) where NDM-1 has not yet been described in A. baumannii, although another single case of A. baumannii producing an NDM-1 variant (NDM-2) was recently reported from Egypt. This brief report further highlights the wide distribution of NDM-producing organisms around the world, their constant evolving spread Research letters