A multidrug-resistant Acinetobacter baumannii isolate recovered from a patient hospitalized in Switzerland after a transfer from Serbia produced the NDM-1 carbapenemase. The bla NDM-1 gene was part of a chromosomally located Tn125 composite transposon bracketed by two copies of the same insertion sequence, ISAba125. This transposon was also associated with the acquisition and expression of the bla NDM-2 gene in an A. baumannii isolate in Germany. Tn125 appears to be the main vehicle for dissemination of bla NDM genes in that species.T he carbapenemase NDM-1, initially identified in Escherichia coli and Klebsiella pneumoniae, has been found mostly in enterobacterial species (12,16,17). However, recent reports have described the occurrence of bla NDM genes in Acinetobacter baumannii. Several NDM-1-positive A. baumannii isolates have been identified in India (10), and two NDM-positive A. baumannii isolates have been recovered in Germany, one being from a patient transferred from a Serbian hospital and producing NDM-1 (6), whereas the other produced NDM-2 (one amino acid substitution with respect to NDM-1) and had been recovered from a patient transferred from an Egyptian hospital (isolate ML) (9). Although the Indian subcontinent is considered a reservoir of NDM-1 producers (17), recent reports indicate that at least the Balkan states and the Middle East regions could also be potential reservoirs (13,21).In a recent work, Pfeifer et al. (18) reported that the bla NDM-1 gene identified in A. baumannii isolate 161/07 from Germany (from a patient transferred from Serbia) (6) was located inside a composite transposon bracketed by two copies of insertion sequence ISAba125.A retrospective survey focusing on multidrug-resistant Gramnegative isolates identified several non-clonally related NDM-1-producing isolates from three patients who had been hospitalized in Geneva University Hospitals, Switzerland, from March 2009 to October 2010. One E. coli and one K. pneumoniae isolate were recovered from the same patient, who had been transferred from Serbia (22). In both isolates, the bla NDM-1 gene was identified on the same 150-kb IncA/C-type plasmid (20). Further investigations showed that this patient also carried a multidrug-resistant A. baumannii isolate that had been recovered from rectal swabs.A. baumannii isolate JH was resistant to all ␤-lactams, including carbapenems (MICs of imipenem, ertapenem, doripenem, and meropenem measured by Etest [AB bioMérieux; Solna, Sweden] were all Ͼ32 g/ml) according to the CLSI guidelines (3). It was also resistant to gentamicin, amikacin, chloramphenicol, tetracycline, and fluoroquinolones and remained susceptible to tobramycin and netilmicin, with MICs of colistin, rifampin, and tigecycline being at 0.5, 1, and 1 g/ml, respectively. PCR and sequencing revealed that A. baumannii JH harbored the bla NDM-1 gene. Screening for additional ␤-lactamase genes and for 16S RNA methylase genes as reported previously (1, 23) showed that A. baumannii JH was coharboring another carbapenemase gene, ...

A clinical Escherichia coli isolate resistant to all ␤-lactams, including carbapenems, expressed a novel metallo-␤-lactamase (MBL), NDM-4, differing from NDM-1 by a single amino acid substitution (Met154Leu). NDM-4 possessed increased hydrolytic activity toward carbapenems and several cephalosporins compared to that of NDM-1. This amino acid substitution was not located in the known active sites of NDM-1, indicating that remote amino acid substitutions might also play a role in the extended activity of this MBL.A cquired metallo-␤-lactamases (MBLs) are emerging resistance determinants in clinically relevant Gram-negative species (19). NDM-1 (New Delhi metallo-␤-lactamase 1) has been recently identified, being first described from Klebsiella pneumoniae and Escherichia coli isolated in Sweden in 2008 from an Indian patient (23). NDM-1, as is the case for any MBL, confers a broad-spectrum ␤-lactam resistance, hydrolyzing penicillins, cephalosporins, and carbapenems but sparing monobactams (23). The rapid and large dissemination of NDM-1-producing Gram-negative species has been emphasized in many reports that have been published in the last 2 years (13,16,20). In Enterobacteriaceae, the bla NDM-1 gene has been shown to be carried by different plasmid types (IncA/C, IncF, IncL/M, or untypeable) (13,16,17). Most bla NDM-1 -encoding plasmids coharbored multiple and variable resistance determinants, including those for ␤-lactams, quinolones, aminoglycosides, rifampin, chloramphenicol, and macrolides (13,16,17). The bla NDM-1 gene has been widely identified in Enterobacteriaceae but also in Acinetobacter baumannii from Germany, India, the United Kingdom, and China (4, 5, 10, 11). In addition, NDM-2-producing A. baumannii isolates have been reported from Egypt and Israel (7, 10). NDM-2 differs from NDM-1 by a single amino acid substitution (Pro28Ala) located in the leader peptide of the enzyme that does not modify its hydrolytic properties compared to those of NDM-1 (7, 21). We report here the identification of a novel NDM variant that possesses extended hydrolytic properties.E. coli I5 was recovered from a urinary culture of a patient hospitalized in India in January 2010. Susceptibility testing was performed by disk diffusion assay (Sanofi-Diagnostic Pasteur, Marnes-la-Coquette, France) as previously described (6a). Results were interpreted according to the CLSI guidelines (6a). The MICs were determined by Etest (AB bioMérieux, Solna, Sweden) on Mueller-Hinton agar plates at 37°C. E. coli I5 was resistant to all ␤-lactams, including imipenem, meropenem, and ertapenem (Table 1). This isolate was additionally resistant to all tested aminoglycosides and fluoroquinolones. Production of MBL was assessed using Etest MBL (AB bioMérieux, Solna Sweden), which gave a positive result. Whole-cell DNA of E. coli isolate I5 was extracted using a QiaAmp minikit according to manufacturer recommendations (Qiagen, Courtaboeuf, France), and DNA was used as a template for the detection of different ␤-lactamases and 16S rRNA methylase genes...

In addition, a polymorphism complicated by the incidence of the quantitative variations is detectable in both pH conditions. Locus a sl -Cn appears to control variant a, l -CnA, at least two forms of variant a sl -CnB which differ in their synthesis rate, and variant a sl -CnC. The frequencies of variant a sl -CnA (0.08-0.10) and of the group of type a s i-CnB (0.89-0.90) are very similar in the three flocks ; the variant a 51 -CnC is less frequent and has only been found in the milk of Saanen goats (0.03 in the pure bred flock of Brouessy).A polymorphism of a. 2 casein is detectable in both pH conditions. It is controlled by two alleles of the a s2 -Cn locus, a s2 -Cn A and U , 2 -Cn', whose frequencies are almost identical in the three flocks (0.85-0.87 for a s2 -Cn A ). Limited data suggest that loci a sl -Cn and a s2 -Cn are linked in the goat, as in cattle.

No abstract

Une analyse biochimique et génétique du complexe des « caséines a s » de la chèvre a été effectuée à l'aide d'échantillons de lait individuels provenant d'animaux des races Alpine chamoisée et Saanen, et de sujets croisés, dérivés pour la plupart de ces deux races, élevés dans trois grands troupeaux (Brouessy, Bourges et Moissac). Contrairement à ce qui paraissait acquis depuis le travail de R ICHARDS O N & C REAMER (1975), le lait de chèvre contient de la caséine a si ; on y retrouve donc les quatre mêmes espèces de caséine que dans le lait de vache (a.,[, a,2, ! (i et x). Les caséines a s1 et a 82 , dont les fractions sont en partie superposées après électrophorèse en gel d'amidon à pH 8,6, sont par contre bien séparées après électrophorèse en gel d'amidon à pH 3. L'électrophorèse en gel acide permet de mettre en évidence des différences nettes et répétables dans la teneur des laits individuels en caséine a 81 , celle-ci paraissant même manquer dans certains échantillons, dits de « type nul ». Des essais de dosage par la technique enzymatique de R IBADEAU-D UMAS (1968) indiquent toutefois que la caséine a si existe dans ces échantillons où elle représente de l'ordre de 8 p. 100 de la caséine totale (Mole/Mole) contre 25 p. 100 environ dans les échantillons à teneur « élevée N. La proportion des chèvres produisant un lait à faible teneur en caséine a sl , types nuls compris, est de 27, 33 et 47 p. 100 respectivement, dans les trois troupeaux étudiés. Un polymorphisme dont l'étude est compliquée par l'existence des variations quantitatives est par ailleurs décelable aux deux conditions de pH. Le locus a 81-Cn contrôlerait le variant a s1-CnA, deux formes au moins du variant a s1-CnB différant par leur taux de synthèse, et le variant a s1-CnC. Les fréquences du variant a 81-CnA (0,08 à 0,10) et de l'ensemble de type «, l-CnB (0,89-0,90) sont très voisines dans les trois troupeaux ; le variant a s t-CnC, plus rare, n'a été trouvé que chez des animaux de race Saanen (0,03 dans le troupeau de race pure de Brouessy). Un polymorphisme de la caséine a, 2 est décelable dans les deux conditions de pH. Il est contrôlé par deux allèles du locus a s2-Cn, a s2-Cn" et a, 2-Cn', dont les fréquences sont très voisines dans les trois troupeaux (0,85 à 0,87 pour a s2-Cn"). Des données limitées suggèrent que les loci a st-Cn et as2-Cn sont liés chez la chèvre, comme chez la vache. Mots clés : Chèvre, caséines a Sl , caséine a s2 , polymorphisme, type nul, liaison génétique. (1) Ce travail reprend et développe les résultats d'une thèse de 3 1 cycle

This constitutes the largest experience with A. baumannii reported to date from a single center. Half of all isolates were respiratory specimens and were from adult ICUs, especially trauma. Even though this was a polyclonal process, a single clone was identified in the hospital through a 6-year span.

bThe Carba NP test has been evaluated to detect carbapenemase-producing Pseudomonas spp. directly from blood cultures. This rapid and cost-effective test permits an early identification of carbapenemase-producing Pseudomonas spp. directly from blood cultures with excellent sensitivity and specificity. Results may be useful in particular for guiding the first-line therapy and epidemiological purposes.