Nicolas Fortineau

Performance of chromID ESBL, a chromogenic medium for detection of Enterobacteriaceae producing extended-spectrum beta-lactamases.

The chromogenic agar medium chromID ESBL (bioMérieux) was compared with BLSE agar medium (AES) for selective isolation and presumptive identification of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae from clinical samples. A total of 765 samples (468 rectal swabs, 255 urine samples and 42 pulmonary aspirations) obtained from 547 patients was processed. All bacterial strains isolated on either medium were further characterized using biochemical tests, and ESBL producers were confirmed by synergy testing. Genetic characterization of ESBL genes was determined by PCR. A total of 33 ESBL-producing Enterobacteriaceae strains [Escherichia coli (n=16), Klebsiella pneumoniae (n=8), Enterobacter spp. (n=3), Citrobacter spp. (n=5) and Proteus mirabilis (n=1)] was recovered. The sensitivity after 24 h incubation was 88 % for chromID ESBL and 85 % for BLSE agar. At 48 h, the sensitivity of chromID ESBL increased to 94 % and was higher than that obtained with BLSE agar. The positive predictive value at 24 h for chromID ESBL was 38.7 % [95 % confidence interval (95 % CI) 28.3 -50.2 %)], which was significantly higher than that for BLSE agar [15.4 %, 95 % CI 10.1 -21.5 %]. On both media, false-positive results were mostly due to Pseudomonas aeruginosa and to Enterobacteriaceae overproducing chromosomal cephalosporinase (Enterobacter spp.) or a chromosomal penicillinase (Klebsiella oxytoca). This study showed that chromID ESBL, a ready-to-use chromogenic selective medium, is sensitive and specific for rapid, presumptive identification of ESBL-producing Enterobacteriaceae. Its chromogenic properties and its selectivity are particularly useful in specimens containing resident associated flora.

First Nosocomial Outbreak of Vancomycin-Resistant Enterococcus faecium Expressing a VanD-Like Phenotype Associated with a vanA Genotype

ABSTRACT Although enterococci expressing acquired vancomycin resistance phenotype have been reported increasingly worldwide, they have been rarely reported in France. From August to December 2004 we faced an outbreak of vancomycin-resistant Enterococcus faecium (VRE) isolates in the nephrology department at Bicêtre Hospital (K.-Bicêtre, France). The expression of the glycopeptide resistance varied among the 26 VRE isolates, with vancomycin MICs ranging from 12 to >256 μg/ml, whereas teicoplanin MICs ranged from 4 to 48 μg/ml. However, several strains appeared to be susceptible to glycopeptides according to disk diffusion testing and expressed resistance only after subculture with glycopeptides. In addition, a heterogeneous expression of glycopeptide resistance was also observed. This so-called VanD-like phenotype of resistance (low-level resistance to vancomycin and mostly susceptibility to teicoplanin) was surprisingly associated with a vanA gene. Plasmid extraction and mating-out experiments indicated that the vanA gene was located on a 200-kb self-transferable plasmid. Pulsed-field gel electrophoresis identified mostly dissemination of a single clone, whereas diffusion of the VanA-positive plasmid in different genomic backgrounds had also occurred. The vanA gene was part of a vanA-type operon for expression of resistance located on a Tn1546-like transposon. Sequencing of this transposon identified insertion of insertion sequence IS16 in the vanY gene that encodes a d,d-carboxypeptidase that might explain in part the peculiar VanD-type phenotype of resistance. This report is the first description of a VRE outbreak in France and underlines the difficulty in detecting this organism due to variability on the expression of the glycopeptide resistance trait, if any.

International Transfer of NDM-1-Producing Klebsiella pneumoniae from Iraq to France

The carbapenemase NDM-1 was initially identified in Escherichia and Klebsiella pneumoniae in Sweden from a patient transferred from India (10). Since then, it has been identified in many enterobacterial species and isolates from patients in the United Kingdom, India, and Pakistan (4). In addition, recent reports have indicated the spread of NDM-1 producers in many different countries, including Austria, Australia, Belgium, Canada, Denmark, France, Germany, Kenya, the Netherlands, Norway, the Sultanate of Oman, and the United States (6-9). Most of these reports indicated a likely source of NDM-1 producers located in the Indian subcontinent, with both hospital and community acquisition. However, a detailed analysis of the clinical cases indicated that importation of NDM-1 isolates may also have originated from Balkan countries, such as Kosovo, Serbia, Montenegro, and Bosnia and Herzegovina, which may constitute an additional reservoir for NDM-1 producers (6). n nA 22-year-old Iraqi male resident in Baghdad was admitted at the Bicetre Hospital (suburb of Paris) on 8 November 2010, following a direct transfer from Baghdad, Iraq. He had been a victim of a terrorist attack at the Baghdad cathedral that killed over 50 people on 31 October 2010. He had a wounded shoulder and was immediately hospitalized at the Ibn Al Nafees Hospital of Baghdad, where he was operated on and stayed for 5 days. At the Bicetre Hospital, he was screened for multidrug-resistant bacteria, including extended-spectrum β-lactamase (ESBL) and carbapenemase producers, methicillin-resistant Staphylococcus aureus, and glycopeptide-resistant enterococci. Rectal swabs grew only on ChromID ESBL culture medium (bioMerieux, La Balme-les-Grottes, France) (5). K. pneumoniae isolate IBN was obtained, which showed resistance or decreased susceptibility to all β-lactams, including carbapenems (the MICs of imipenem, ertapenem, doripenem, and meropenem were 2, 8, 2, and 3 μg/ml, respectively), according to the CLSIs updated guidelines (1). It was also resistant to gentamicin, kanamycin, tobramycin, sulfonamides, rifampin, chloramphenicol, and fluoroquinolones but remained susceptible to amikacin and fosfomycin, the MICs of tigecycline and colistin being 0.25 and 0.5 μg/ml, respectively. The patient did not develop any infection while hospitalized in France. He was neither treated with antibiotics nor decontaminated (actually not recommended for carriage of multidrug-resistant Enterobacteriaceae). n nPCR, sequencing, and plasmid analysis revealed that K. pneumoniae IBN harbored the blaNDM-1 carbapenemase gene, in addition to a blaCTX-M-15 ESBL gene, each located on a different plasmid (100 and 160 kb in size, respectively). Screening for additional β-lactamase genes and for 16S RNA methylase genes, as reported previously (9), showed that K. pneumoniae IBN was coharboring the blaSHV-11 and blaOXA-1 genes, but no 16S RNA methylase gene was identified. Multilocus sequence typing was performed as described worldwide (3) to evidence a possible link with other recently identified NDM-1-producing K. pneumoniae isolates, and the results were analyzed by eBURST (http://pubmlst.org). The results showed that isolate IBN belonged to the ST147 sequence type, whereas the NDM-1-positive K. pneumoniae 05-506 index strain and K. pneumoniae isolates recovered in India and in the Sultanate of Oman belonged to the ST14 type, both types differing significantly (2, 7). Interestingly, the only report of ST147-type K. pneumoniae so far corresponds to a clonal spread that has been identified in Hungary (2). This Hungarian ST147 clone was susceptible to carbapenems, but it harbored a blaCTX-M-15 plasmid and was resistant to fluoroquinolones (2), as observed for isolate IBN from Iraq. It may therefore be speculated that these isolates could be clonally related. n nConsidering that one of the two NDM-1-producing K. pneumoniae isolates previously identified from Oman could not be traced back to the Indian subcontinent, this report provides an additional clue that the Middle East might also be a reservoir for NDM-1 producers. This result should be taken in account when taking care of any civilian or soldier hospitalized in Iraq and transferred abroad. It also suggests that the spread of NDM-1 producers is already much wider than suspected. Finally, it strengthens the value of systematic screening for multidrug-resistant bacteria for preventing the development of nosocomial outbreaks of carbapenem-resistant Enterobacteriaceae, as recommended in reference 6.

Cross-border transmission of OXA-48-producing Enterobacter cloacae from Morocco to France

Service de Bacteriologie-Virologie, INSERM U914 ‘Emerging Resistance to Antibiotics’, Hopital de Bicetre, Assistance Publique/ Hopitaux de Paris, Faculte de Medecine et Universite Paris-Sud, K.-Bicetre, France; Laboratoire de Bacteriologie-Virologie-Hygiene, EA3064, Groupe Immunite des Muqueuses et Agents Pathogenes, PRES de Lyon, Universite et CHU de Saint-Etienne, Saint-Etienne, France *Corresponding author. Service de Bacteriologie-Virologie-Hygiene, Hopital de Bicetre, 78 rue de General Leclerc, 94275 Le Kremlin-Bicetre Cedex, France. Tel: +33-1-45-21-36-32; Fax: +33-1-45-21-63-40; E-mail: nordmann.patrice@bct.aphp.fr

NDM-1-Producing Acinetobacter baumannii from Algeria

Over the last decade, nosocomial infections with Acinetobacter baumannii have been described with an increasing trend toward multidrug resistance, mostly in intensive care units (ICUs) ([6][1], [9][2], [11][3]). The main mechanism of resistance to carbapenems in A. baumannii is the production of

Endoscopy-associated transmission of carbapenem-resistant Klebsiella pneumoniae producing KPC-2 β-lactamase

Service de Bacteriologie-Virologie, INSERM U914: ‘Emerging Resistance to Antibiotics’, Hopital de Bicetre, Assistance PubliqueHopitaux de Paris, Universite Paris-Sud, 94275 Le Kremlin-Bicetre, France; Service d’Hepato-gastro-enterologie, Hopital de Bicetre, Assistance Publique-Hopitaux de Paris, Universite Paris-Sud, 94275 Le Kremlin-Bicetre, France; Service de chirurgie digestive, Hopital de Bicetre, Assistance Publique-Hopitaux de Paris, Universite ParisSud, 94275 Le Kremlin-Bicetre, France

Novel Chromogenic Medium for Detection of Vancomycin-Resistant Enterococcus faecium and Enterococcus faecalis

ABSTRACT Vancomycin-resistant enterococci (VRE) are becoming widespread worldwide, and the rapid identification of VRE carriers from surveillance cultures is crucial for the efficient control of their spread. We assessed a new selective chromogenic medium, chromID VRE (bioMérieux, France), that enhanced the isolation and presumptive identification of VRE directly from rectal swabs and reduced unnecessary confirmatory and time-consuming tests.

Whole-Genome Sequence of a European Clone II and OXA-72-Producing Acinetobacter baumannii Strain from Serbia

ABSTRACT We report here the draft genome sequence of a carbapenem-resistant Acinetobacteru2009baumannii strain isolated from a patient, a strain which previously stayed in Serbia. This isolate possessed the blaOXA-72 carbapenemase gene. The draft genome sequence consists of a total length of 3.91 Mbp, with an average G+C content of 38.8%.

First Occurrence of OXA-72-Producing Acinetobacter baumannii in Serbia

ABSTRACT Here, we characterized the first OXA-72-producing Acinetobacter baumannii isolate (designated MAL) recovered from a urine sample from a Serbian patient. Antimicrobial susceptibility testing, plasmid analysis, and whole-genome sequencing (WGS) were performed to fully characterize the resistome of the A. baumannii MAL clinical isolate. The isolate was multidrug resistant and remained susceptible only to colistin and tigecycline. PCR analysis revealed the presence of the carbapenemase OXA-72, an OXA-40 variant. Extraction by the Kieser method revealed the presence of two plasmids, and one of these, a ca. 10-kb plasmid, harbored the blaOXA-72 gene. WGS revealed 206 contigs corresponding to a genome of 3.9 Mbp in size with a G+C content of 38.8%. The isolate belonged to sequence type 492 and to worldwide clone II (WWCII). Naturally occurring β-lactamase-encoding genes (blaADC-25 and blaOXA-66) were also identified. Aminoglycoside resistance genes encoding one aminoglycoside adenyltransferase (aadA2), three aminoglycoside phosphatases (strA, strB, aphA6), and one 16S RNA methylase (armA) conferring resistance to all aminoglycosides were identified. Resistance to fluoroquinolones was likely due to mutations in gyrA, parC, and parE. Of note, the resistome matched perfectly with the antibiotic susceptibility testing results.

OXA-244-Producing Escherichia coli Isolates, a Challenge for Clinical Microbiology Laboratories

ABSTRACT OXA-244 is a single-point-mutant derivative of OXA-48 displaying reduced carbapenemase activity. Here, we report the microbiological features of seven OXA-244-producing Escherichia coli isolates. Only one isolate grew on ChromID Carba Smart medium (bioMérieux), but six of the seven isolates grew on ChromID extended-spectrum-β-lactamase (ESBL) medium (bioMérieux), as they coproduced an ESBL and/or a plasmid-encoded cephalosporinase. The production of a carbapenemase was detected in 57.1%, 71.4%, 71.4%, and 100% of the E. coli isolates using the Carba NP test, the Rapidec Carba NP test (bioMérieux), a matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) hydrolysis assay (Bruker), and the OXA-48 K-SeT assay (Coris BioConcept), respectively. Our results indicate that OXA-244-producing E. coli isolates are difficult to detect, which may lead to their silent spread.