c An NDM-1 carbapenemase-producing Pseudomonas aeruginosa isolate was recovered from a patient hospitalized in France after a previous hospitalization in Serbia. Genetic studies revealed that the bla NDM-1 gene was surrounded by insertion sequence ISAba125 and a truncated bleomycin resistance gene. This bla NDM-1 region was a part of the variable region of a new complex class 1 integron bearing IS common region 1 (ISCR1). The presence of ISPa7 upstream of this integron suggests insertion in a chromosomally located Tn402-like structure. Since the first description in Klebsiella pneumoniae and Escherichia coli, the NDM-1 carbapenemase has been identified in many different species, including Enterobacteriaceae and Acinetobacter baumannii (1, 2). To date, the Indian subcontinent and, more recently, Balkan countries constitute a reservoir of NDM producers (2-5). The corresponding gene, which is usually plasmid borne, is spreading worldwide in Enterobacteriaceae (2) and also in species isolated from water supplies in India, such as Pseudomonas putida and Pseudomonas pseudoalcaligenes (6). Recent reports have described the occurrence of chromosomally located bla NDM-1 in Acinetobacter baumannii related to transposon Tn125 (7,8). Before 2012, only one report of two NDM-1-producing Pseudomonas aeruginosa isolates was described. Both were isolated in Serbia (9). To date, the transfer mechanisms, location, and bla NDM-1 genetic environment in P. aeruginosa remain unknown.Here, we report the genetic environment of the bla NDM-1 gene in the first NDM-1-producing P. aeruginosa isolate from France, HIABP11. The isolate was recovered from a urine culture of a 63-year-old female patient, who was admitted to the infectious unit of the Bégin military hospital (Saint-Mandé, France) for an acute pyelonephritis complicated with renal microabscesses (10). Three months before her admission, the patient was hospitalized in Serbia for a posttraumatic fronto-temporo-parietal subdural hematoma surgical drainage. P. aeruginosa HIABP11 exhibited serotype O11 (monoclonal and polyclonal antisera; Bio-Rad Laboratories, Marne-la-Coquette, France). Susceptibility testing (disk diffusion and Etest) performed and interpreted according to the EUCAST guidelines showed that P. aeruginosa HIABP11 was resistant to all carbapenems (imipenem, meropenem, and doripenem) and antipseudomonal cephalosporins, as well as to aminoglycosides and fluoroquinolones. The isolate remained susceptible to piperacillin-tazobactam (MIC of 12 mg/liter) and colistin (MIC of 2 mg/liter) and intermediate to aztreonam (MIC of 3 mg/liter). Metallo-␤-lactamase (MBL) production in the isolate was suggested by positive EDTA (bioMérieux, Marcy l'Etoile, France) and dipicolinic acid (KPCϩMBL Confirm ID Pack; Rosco Diagnostica, Taastrup, Denmark) tests with imipenem and meropenem, respectively. PCR experiments were carried out on purified DNA with primers specific for known MBL genes, as previously described (11). Sequencing of amplification products confirmed the presence of the bla ...

Butyrylcholinesterase deficiency is characterized by prolonged apnea after the use of muscle relaxants (suxamethonium or mivacurium) in patients who have mutations in the BCHE gene. Here, we report a case of prolonged neuromuscular block after administration of suxamethonium leading to the discovery of a novel BCHE variant (c.695T>A, p.Val204Asp). Inhibition studies, kinetic analysis and molecular dynamics were undertaken to understand how this mutation disrupts the catalytic triad and determines a “silent” phenotype. Low activity of patient plasma butyrylcholinesterase with butyrylthiocholine (BTC) and benzoylcholine, and values of dibucaine and fluoride numbers fit with heterozygous atypical silent genotype. Electrophoretic analysis of plasma BChE of the proband and his mother showed that patient has a reduced amount of tetrameric enzyme in plasma and that minor fast-moving BChE components: monomer, dimer, and monomer-albumin conjugate are missing. Kinetic analysis showed that the p.Val204Asp/p.Asp70Gly-p.Ala539Thr BChE displays a pure Michaelian behavior with BTC as the substrate. Both catalytic parameters Km = 265 µM for BTC, two times higher than that of the atypical enzyme, and a low Vmax are consistent with the absence of activity against suxamethonium. Molecular dynamic (MD) simulations showed that the overall effect of the mutation p.Val204Asp is disruption of hydrogen bonding between Gln223 and Glu441, leading Ser198 and His438 to move away from each other with subsequent disruption of the catalytic triad functionality regardless of the type of substrate. MD also showed that the enzyme volume is increased, suggesting a pre-denaturation state. This fits with the reduced concentration of p.Ala204Asp/p.Asp70Gly-p.Ala539Thr tetrameric enzyme in the plasma and non-detectable fast moving-bands on electrophoresis gels.

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