CHROMagar Acinetobacter medium for detection of carbapenemase-producing Acinetobacter spp. strains from spiked stools

The recently modified CHROMagar Acinetobacter medium was evaluated for detection of carbapenemase-producing Acinetobacter baumannii from spiked stools. A total of 45 Acinetobacter spp. isolates were tested. The CHROMagar Acinetobacter medium had a high sensitivity of 86.5% and a specificity of 75%. This medium is likely to be most useful for controlling outbreaks and in endemic situations

Clonal distribution of multidrug-resistant Enterobacter cloacae

A multilocus sequence typing (MLST) scheme including 7 housekeeping genes was used to evaluate whether the current spread of multidrug-resistant Enterobacter cloacae isolates worldwide might be associated to specific successful clones. Fifty E. cloacae clinical isolates of worldwide origin, with various β-lactamase content, and recovered at different periods of time were studied. Forty-four sequence types were identified, highlighting a high clonal diversity with 3 main lineages. This study revealed that a precise identification of the isolates by sequencing of the chromosomal ampC gene of E. cloacae would provide a significant added value to improve the reliability of the MLST scheme

Complete sequence of the IncA/C 1 plasmid pCf587 carrying bla PER-2 from citrobacter freundii

The bla PER-2 -harboring plasmid pCf587 (191,541 bp) belongs to lineage IncA/C 1 and is closely related to pRA1. It contains a large resistance island including the bla PER-2 gene between two copies of ISKox2-like elements, the toxin-antitoxin module pemK-pemI, several other resistance genes inserted within a Tn2 transposon, a Tn21-like structure, and a class 1 integron. pCf587 belongs to sequence type 13 (ST13), a new plasmid multilocus sequence typing (pMLST) ST.Fil: Ruggiero, Melina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Cátedra de Microbiología; ArgentinaFil: Girlich, Delphine. Université Paris Sud; FranciaFil: Dabos, Laura. Université Paris Sud; FranciaFil: Power, Pablo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Cátedra de Microbiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Naas, Thierry. Associated French National Reference Center for Antibiotic Resistance “Carbapenemase -producing Enterobacteriaceae; Francia. Université Paris Sud; FranciaFil: Gutkind, Gabriel Osvaldo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Cátedra de Microbiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Integration of the blaNDM-1 carbapenemase gene into Proteus genomic island 1 (PGI1-PmPEL) in a Proteus mirabilis clinical isolate

Objectives To decipher the mechanisms and their associated genetic determinants responsible for β-lactam resistance in a Proteus mirabilis clinical isolate. Methods The entire genetic structure surrounding the β-lactam resistance genes was characterized by PCR, gene walking and DNA sequencing. Results Genes encoding the carbapenemase NDM-1 and the ESBL VEB-6 were located in a 38.5 kb MDR structure, which itself was inserted into a new variant of the Proteus genomic island 1 (PGI1). This new PGI1-PmPEL variant of 64.4 kb was chromosomally located, as an external circular form in the P. mirabilis isolate, suggesting potential mobility. Conclusions This is the first known description of the blaNDM-1 gene in a genomic island structure, which might further enhance the spread of the blaNDM-1 carbapenemase gene among enteric pathogen

Transcriptional regulation of apolipoprotein A-I expression in Hep G2 cells by phorbol ester

AbstractThe regulation of apolipoprotein A-I (apo A-I) gene expression by 12-O-tetradecanoylphorbol 13-acetate (TPA) was investigated in the human hepatoma cell line Hep G2. TPA treatment decreased apo A-I mRNA levels in a time-dependent manner, by up to 50% versus control cells within 24 h. Nuclear run-on transcription assays demonstrated a transcriptional effect of TPA. Using transfection analysis with a plasmid construct containing the −1378/+11 apo A-I promoter fused to the secreted placental alkaline phosphatase (SPAP) reporter gene, we showed that the SPAP activity was decreased to 50% when Hep G2 cells were incubated in the presence of TPA. The inhibitory effect of TPA was still maintained when fragment −253 to −4 of apo A-I promoter was linked to the CAT reporter gene. These data indicate that transcriptional modulation of apolipoprotein A-I gene expression following phorbol ester treatment is transduced by gene elements located between −253 and −4 of the apo A-I promoter

Characterization of BRP_MBL the bleomycin resistance protein associated with the carbapenemase NDM

The metallo-β-lactamase NDM-1 is among the most worrisome resistance determinants and is spreading worldwide among Gram-negative bacilli. A bleomycin resistance gene, bleMBL, downstream of the blaNDM-1 gene has been associated with resistance almost systematically. Here, we characterized the corresponding protein, BRPMBL, conferring resistance to bleomycin, an antitumoral glycopeptide molecule. We have determined whether the expression of the blaNDM-1-bleMBL operon is inducible in the presence of carbapenems and/or bleomycin-like molecules using quantitative reverse transcription-PCR (qRT-PCR), determination of imipenem and zeocin MICs, and carbapenemase-specific activity assays. We showed that the blaNDM- 1-bleMBL operon is constitutively expressed. Using electrophoretic mobility shift and DNA protection assays performed with purified glutathione S- transferase (GST)-BRPMBL, we demonstrated that BRPMBL is able to bind and sequester bleomycin-like molecules, thus preventing bleomycin-dependent DNA degradation. In silico modeling confirmed that the mechanism of action required the dimerization of the BRPMBL protein in order to sequester bleomycin and prevent DNA damage. BRPMBL acts specifically on bleomycin-like molecules since cloning and expression of bleMBL in Staphyloccoccus aureus did not confer cross-resistance to any other antimicrobial glycopeptides such as vancomycin and teicoplanin

Multiple colonization with highly resistant bacteria: carbapenemase-producing Enterobacteriaceae, carbapenemase-producing Pseudomonas aeruginosa, carbapenemase-producing Acinetobacter baumannii, and glycopeptide-resistant Enterococcus faecium

The dissemination of carbapenemase-producing bacteria worldwide is an important source of concern because carbapenemase producers are multidrug resistant (Nordmann and Poirel, 2014). National guidelines increasingly recommend a systematic screening of at least carbapenemase-producing Enterobacteriaceae (CPE) and glycopeptide-resistant enterococci (GRE) in patients admitted to hospitals who have been hospitalized aboard during the preceding 12 months (Lepelletier et al., 2011). We have investigated the occurrence of colonization and infection with multiple highly resistant bacteria of more than 4 different genus in 2 patients directly transferred from a foreign country.In June 2014, a 33-year-old French man (patient A) was admitted for a suicide attempt in a Vietnamese hospital where he was treated during 10 days for pneumonia with piperacillin + tazobactam before his transfer to Necker-Enfants Malades University Hospital in Paris, France. At the day of his hospitalization in France, distal protected pulmonary samples were collected, and imipenem was administered subsequently to a persistent fever. In addition, systematic screening to detect carbapenemase producers and GRE was also performed. Screening of extended spectrum β-lactamase (ESBL) producing Enterobacteriaceae, carbapenemase producers, and GRE was done on selective media (bioMérieux, La Balme-les-Grottes, France) ChromID ESBL, ChromID Carba Smart, and VRE medium, respectively. Carbapenemase production was identified using the Carba NP test for Enterobacteriaceae (Dortet et al., 2014a) and Pseudomonas aeruginosa ( Dortet et al., 2012) and CarbAcineto NP test for Acinetobacter baumannii ( Dortet et al., 2014b). Definitive identifications of resistance determinant were done by PCR amplifications followed by sequencing. Pulmonary samples grew an OXA-23–producing A. baumannii isolate and an IMP-1–producing P. aeruginosa ( Table 1). Screening identified also that the patient was colonized with a KPC-2–producing Klebsiella pneumoniae, a CTX-M-15–producing K. pneumoniae, and a VanA-positive glycopeptide-resistant Enterococcus faecium ( Table 1)

Evaluation of Etest® strips for detection of KPC and metallo-carbapenemases in Enterobacteriaceae

The performance of Etest KPC and MBL strips (bioMérieux) was evaluated as compared to other phenotypic tests for detecting carbapenemases of the KPC-type and metallo-β-lactamases, respectively, on 133 well-characterized enterobacterial isolates. KPC and meropenem-containing MP/MPI Etest had high sensitivity (>92 %) and specificity (>97 %)