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P Nordmann

Publications and source records attributed to P Nordmann.

At least 19 recordsLinked to original sources
PubMed2006

Cephalosporinase over-expression resulting from insertion of ISAba1 in Acinetobacter baumannii.

ISAba1-like sequences were identified immediately upstream of the bla(ampC) gene in ceftazidime-resistant Acinetobacter baumannii isolates, but were absent in ceftazidime-susceptible A. baumannii isolates. AmpC over-expression resulted from insertion of ISAba1-like sequences upstream of bla(ampC). ISAba1 provided strong promoter sequences, and it was demonstrated that the change in the ribosome binding site sequence resulting from insertion of ISAba1 did not influence expression of the bla(ampC) gene. Sequence analysis revealed that AmpC sequences of A. baumannii isolates were almost identical and that ISAba1 elements had a high percentage of identity.

Acinetobacter baumannii↗
PubMed2006

Carbapenem resistance in Acinetobacter baumannii: mechanisms and epidemiology.

The increasing trend of carbapenem resistance in Acinetobacter baumannii worldwide is a concern since it limits drastically the range of therapeutic alternatives. Metallo-beta-lactamases (VIM, IMP, SIM) have been reported worldwide, especially in Asia and western Europe, and confer resistance to all beta-lactams except aztreonam. The most widespread beta-lactamases with carbapenemase activity in A. baumannii are carbapenem-hydrolysing class D beta-lactamases (CHDLs) that are mostly specific for this species. These enzymes belong to three unrelated groups of clavulanic acid-resistant beta-lactamases, represented by OXA-23, OXA-24 and OXA-58, that can be either plasmid- or chromosomally-encoded. A. baumannii also possesses an intrinsic carbapenem-hydrolysing oxacillinase, the expression of which may vary, that may play a role in carbapenem resistance. In addition to beta-lactamases, carbapenem resistance in A. baumannii may also result from porin or penicillin-binding protein modifications. Several porins, including the 33-kDa CarO protein, that constitute a pore channel for influx of carbapenems, might be involved in carbapenem resistance.

Acinetobacter Infections↗
PubMed2006

Genotypic diversity and antibiotic susceptibility of Acinetobacter baumannii isolates in a Bulgarian hospital.

A set of 18 Acinetobacter baumannii isolates, collected prospectively in a Bulgarian hospital during episodes of increased A. baumannii occurrence during 2000-2002, was investigated for genotypic diversity and antibiotic susceptibility. Four genotypes were identified by amplified fragment length polymorphism genomic fingerprinting, one of which (type 1) accounted for 13 isolates, indicating that a specific strain was predominant. The single isolate allocated to type 2 was identified to European clone I. All isolates were resistant to multiple antibiotics, but most retained susceptibility to tobramycin and colistin, and all except one were susceptible to imipenem.

Acinetobacter Infections↗
PubMed2006

Plasmid-mediated quinolone resistance determinant qnrS in Enterobacter cloacae.

PCR was used to investigate the occurrence of the plasmid-encoded quinolone resistance determinants qnrA and qnrS among diarrhoeagenic enterobacterial isolates recovered from Hanoi, Vietnam, during the period March 2001 to April 2002. In total, 162 Escherichia coli isolates, 28 Shigella isolates and three Enterobacter cloacae isolates were negative for qnrA, while a single Ent. cloacae isolate harboured a 50-kb qnrS-positive conjugative plasmid. Cloning and sequencing identified a qnrS gene bracketed by open reading frames identical to those surrounding the qnrS gene of a Shigella flexneri isolate from Japan, thereby suggesting a common mechanism of acquisition.

Bacterial Proteins↗
PubMed2006

Nosocomial spread of OXA-58-positive carbapenem-resistant Acinetobacter baumannii isolates in a paediatric hospital in Greece.

Twelve non-repetitive Acinetobacter baumannii isolates producing the carbapenem-hydrolysing oxacillinase OXA-58 were recovered from patients in the same paediatric hospital in Athens, Greece, between November 2003 and May 2005. All isolates were clonally related, but the bla(OXA-58) gene was not always plasmid-located and there were variations in the DNA sequences surrounding the OXA-58 gene in different isolates. This study emphasises the importance of the bla(OXA-58) carbapenemase gene in conferring carbapenem resistance among A. baumannii isolates in Greece.

Acinetobacter Infections↗
PubMed2006

Pyrosequencing for rapid identification of carbapenem-hydrolysing OXA-type beta-lactamases in Acinetobacter baumannii.

Carbapenem-resistant Acinetobacter baumannii isolates producing carbapenem-hydrolysing oxacillinases are emerging worldwide. These enzymes are divided into four phylogenetic subgroups: OXA-23-like, OXA-51-like, OXA-24-like and OXA-58-like. A PCR-based approach linked to pyrosequencing analysis was developed to identify the genes for these beta-lactamases. Carbapenem-hydrolysing oxacillinases were rapidly and unambiguously identified in a collection of carbapenem-resistant clinical isolates of A. baumannii and Acinetobacter junii. Pyrosequencing may provide a rapid tool for identification of OXA variants, thus avoiding delays inherent in classical sequencing methods.

Acinetobacter↗
PubMed2005

Three-year survey of community-acquired methicillin-resistant Staphylococcus aureus producing Panton-Valentine leukocidin in a French university hospital.

A retrospective survey was conducted at Bicêtre Hospital, France from January 2001 to September 2003 to screen for S. aureus isolates with a typical phenotype previously involved in necrotizing pneumonia in France. They were resistant to oxacillin and kanamycin, of intermediate susceptibility to fusidic acid, and susceptible to tobramycin and fluoroquinolones. Seventeen isolates were found and 16 were viable. The Panton-Valentine leukocidin (PVL) genes, various toxin genes and SCCmec IV and agr3 alleles were detected in all isolates. The clonal origin of these isolates was demonstrated by pulsed-field gel electrophoresis. Fourteen isolates were community-acquired methicillin-resistant Staphylococcus (CA-MRSA) isolated from previously healthy patients with skin or soft tissue infections. Three infections were of nosocomial origin, underlining that these PVL-producing CA-MRSA strains may also be hospital acquired. Five CA-MRSA isolates with an identical resistance phenotype collected in a neighbouring teaching hospital (Hôpital Pitié-Salpétrière, Paris, France) were also PVL positive. Three isolates were clonally related to those of the Bicêtre Hospital whereas two were not. This retrospective study identified PVL-producing CA-MRSA in two Parisian hospitals. The incidence at Bicêtre Hospital was 0.8% of all S. aureus and 2% of all MRSA isolated. Our data indicate that these MRSA isolates might become hospital acquired.

Adolescent↗
PubMed2005

Investigation of a nosocomial outbreak of extended-spectrum beta-lactamase VEB-1-producing isolates of Acinetobacter baumannii in a hospital setting.

A nosocomial outbreak of epidemiologically related VEB-1 extended-spectrum beta-lactamase-producing isolates of Acinetobacter baumannii occurred in 33 patients in an intensive care unit. A case-control study identified previous treatment with third-generation cephalosporins as the only risk factor for A. baumannii acquisition. Rationale for antibiotic use should be strengthened.

Acinetobacter Infections↗
PubMed2005

Nosocomial outbreak of staphylococcal scalded skin syndrome in neonates: epidemiological investigation and control.

Over a three-month period, 13 neonates developed staphylococcal scalded skin syndrome (SSSS) in a maternity unit, between four and 18 days after their birth. An epidemiological and descriptive study followed by a case-control study was performed. A case was defined as a neonate with blistering or peeling skin, and exfoliative toxin A Staphylococcus aureus positive cultures. Controls were selected at random from the asymptomatic, non-colonized neonates born on the same day as the cases. All staff members and all neonates born during the outbreak period were screened for carriage by nasal swabs and umbilical swabs, respectively. S. aureus isolates were polymerase chain reaction (PCR) screened for etA gene and genotyped by pulsed-field gel electrophoresis (PFGE). Two clusters of eight and five cases were identified. Receiving more than one early umbilical care procedure by the same ancillary nurse was the only risk factor identified in the case-control study (odds ratio=15, 95% confidence intervals 2-328). The ancillary nurse suffered from chronic dermatitis on her hands that favoured S. aureus carriage. Exfoliative-toxin-A-producing strains, as evidenced by PCR and indistinguishable by PFGE, were isolated from all but one of the SSSS cases, from four asymptomatic neonates, from two staff members and from the ancillary nurse's hands. Removal of the ancillary nurse from duty, infection control measures (isolation precautions, chlorhexidine handwashing and barrier protections), and treatment of the carriers (nasal mupirocin and chlorhexidine showers) led to control of the epidemic. In conclusion, this study emphasizes the need for tight surveillance of chronic dermatitis in healthcare workers.

Adult↗
PubMed2005

PER-1- and OXA-10-like beta-lactamases in ceftazidime-resistant Pseudomonas aeruginosa isolates from intensive care unit patients in Istanbul, Turkey.

The presence of PER-1- and OXA-10-like beta-lactamases was investigated by PCR in 49 ceftazidime-resistant Pseudomonas aeruginosa isolates from patients hospitalised in the 24-bed general intensive care unit of the Istanbul Faculty of Medicine during a 12-month period between February 1999 and February 2000. The clonal relatedness of the isolates was investigated by random amplified polymorphic DNA (RAPD) analysis, and the sequences of the PER-1 and OXA genes from all isolates were determined. The rates of resistance of the isolates to imipenem, aztreonam and cefepime were 98%, 92% and 96%, respectively, and to piperacillin and piperacillin-tazobactam were 41% and 37%, respectively. Using the double-disk synergy test, 37% (18/49) of the isolates were identified as extended-spectrum beta-lactamase producers. The PER-1 gene was identified in 86% (42/49) and the OXA-10 gene in 55% (27/49) of the ceftazidime-resistant isolates. Of isolates carrying the PER-1 gene, 48% (20/42) also carried the OXA-10 gene. The respective nucleotide sequences were identical for each isolate. Sixteen RAPD patterns were detected among the PER-1-positive isolates, but 60% (25/42) of the PER-1-positive isolates belonged to two distinct patterns, while the remainder exhibited a wide clonal diversity. The results indicated that the prevalence of PER-1- and OXA-10-like beta-lactamases remains high among ceftazidime-resistant P. aeruginosa isolates in Turkey.

Anti-Bacterial Agents↗
PubMed2005

Spread of novel expanded-spectrum beta-lactamases in Enterobacteriaceae in a university hospital in the Paris area, France.

In 2002, 28 non-duplicate enterobacterial isolates producing extended-spectrum beta-lactamases (ESBLs) were collected from infected patients at the Bicêtre Hospital in Paris, France. Escherichia coli was the predominant ESBL-positive enterobacterial species, comprising ten (36%) of the isolates. CTX-M enzymes (CTX-M-3, CTX-M-10, CTX-M-14 and CTX-M-15) were produced by 11 (39%) of the isolates (six E. coli, two Enterobacter cloacae, one Enterobacter aerogenes, one Proteus mirabilis and one Citrobacter freundii). Other ESBLs, such as VEB-1 and PER-1, were also detected, but less frequently.

Citrobacter freundii↗
PubMed2005

Molecular characterization of an epidemic clone of panantibiotic-resistant Pseudomonas aeruginosa.

We describe the molecular characterization of a multiresistant Pseudomonas aeruginosa clone causing an outbreak in the intensive care unit (ICU) of a tertiary-care university hospital. Analysis included antimicrobial susceptibility profile, O-serotyping, pulsed-field gel electrophoresis, and amplified fragment length polymorphism. Resistance mechanisms were characterized, including production of naturally occurring and acquired beta-lactamases, porin expression, and efflux pump systems. Eighteen patients were colonized or infected with multiresistant P. aeruginosa. Multiresistant P. aeruginosa was panresistant to penicillins, cephalosporins, carbapenems, aminoglycosides, and fluoroquinolones and remained susceptible only to colistin. Sixteen isolates (89%) belonged to serotype O:11, pulsed-field gel electrophoresis type A1, and amplified fragment length polymorphism type A. Resistance characterization of this epidemic clone showed an overexpression of the chromosomal cephalosporinase AmpC combined with decreased expression of porin OprD and the absence of metallo-beta-lactamase or extended-spectrum beta-lactamase. An upregulation of the MexXY efflux system due to an agrZ mutation in the mexZ repressor was detected. This epidemic clone was restricted to the ICU and was not found elsewhere in hospital. Contamination of the ICU environment and the hands of an ICU nurse with this clone suggests possible hand-borne transmission. Implementation of contact precautions effectively controlled transmission of the epidemic clone. This study illustrates the ability of multiresistant P. aeruginosa to cause an outbreak with significant morbidity and mortality and underscores the need to identify clonal outbreaks, which require targeted infection control measures.

Cross Infection↗