Environmental persistence of OXA-48-producing Klebsiella pneumoniae in a French intensive care unit.

The spread of carbapenemase-producing Gram-negative rods is an emerging global problem. This study describes the epidemiologic features of an outbreak caused by an environmental reservoir of OXA-48-producing Klebsiella pneumoniae caused by persistence of the bacteria during 20 months in an intensive care unit in France. This report emphasizes the importance of early environmental screening to interrupt the transmission of carbapenemase-producingEnterobacteriaceae.

An adaptive response of Enterobacter aerogenes to imipenem: regulation of porin balance in clinical isolates.

Imipenem (IPM) is a carbapenem antibiotic frequently used in severe hospital infections. Several reports have mentioned the emergence of resistant isolates exhibiting membrane modifications. A study was conducted between September 2005 and August 2007 to survey infections due to Enterobacter aerogenes in patients hospitalised in a French university hospital. Resistant E. aerogenes clinical isolates obtained from patients treated with IPM and collected during the 3 months following initiation of treatment were phenotypically and molecularly characterised for ß-lactamases, efflux pumps activity and outer membrane proteins. Among the 339 patients infected with E. aerogenes during the study period, 41 isolates (12.1%) were resistant to extended-spectrum cephalosporins and 17 patients (5.0%) were treated with IPM. The isolates from these 17 patients presented TEM-24 and basal efflux expression. Following IPM treatment, an IPM-intermediate-susceptible (IPM-I) isolate emerged in 11 patients and an IPM-resistant (IPM-R) isolate in 6 patients. A change in the porin balance (Omp35/Omp36) was observed in IPM-I isolates exhibiting ertapenem resistance. Finally, a porin deficiency (Omp35 and Omp36 absence) was detected in IPM-R isolates associated with efflux pump expression. This study indicates that the alteration in porin expression, including the shift of porin expression and lack of porins, contribute to the E. aerogenes adaptive response to IPM treatment.

Virulence potential of Escherichia coli strains causing asymptomatic bacteriuria during pregnancy.

We compared the virulence properties of a collection of asymptomatic bacteriuria (ABU) Escherichia coli strains to urinary tract infection (UTI) strains isolated from pregnant women in a university hospital over 1 year. The in vitro and in vivo studies suggest that ABU strains presented a virulence behavior similar to that of strains isolated from cases of cystitis.

Faecal carriage of multidrug-resistant Gram-negative bacilli during a non-outbreak situation in a French university hospital.

OBJECTIVES: To determine the prevalence of multidrug-resistant (MDR) Gram-negative bacilli and extended spectrum ß-lactamase (ESBL)-producing isolates in stool specimens obtained from patients hospitalized for acute diarrhoea in a French university hospital. METHODS: Bacteria in stool specimens were screened for ESBL production on Drigalski agar supplemented with ceftazidime, ESBL CHROMagar(®) and CTX CHROMagar(®) media and confirmed by the double-disc synergy test. Genetic detection was performed by PCR and sequencing with bacterial DNA extracted from isolates. RESULTS: The presence of MDR bacteria was markedly high (96 of 303 patients, 31.7%). The majority of MDR bacteria were Enterobacter cloacae (44, 38%) and Escherichia coli (32, 28%). Moreover, the prevalence of ESBL and CTX-M producers among all included patients was 15.8% and 5.9%, respectively. The clone E. coli O25b : H4-ST131 was detected in 63% of CTX-M strains. Surprisingly, 16 carbapenemases (5.3% of patients) were isolated. CONCLUSIONS: The study revealed the wide dissemination of MDR bacteria, including carbapenemase producers, in a French hospital during a non-outbreak situation. Public health efforts to combat emergence and dissemination of MDR organisms need to be developed.

Miniaturized oligonucleotide arrays: a new tool for discriminating colonization from infection due to Staphylococcus aureus in diabetic foot ulcers.

OBJECTIVE: We sought to evaluate the use of oligonucleotide arrays to discriminate colonization from infection due to Staphylococcus aureus in diabetic foot ulcers. RESEARCH DESIGN AND METHODS: We included diabetic patients hospitalized in a diabetic foot department for an episode of foot ulcer. Only patients who had no antibiotic treatment during the previous 6 months were included. At admission, ulcers were classified on clinical examination, according to the Infectious Diseases Society of America system. Seventy-two patients with a culture positive only for S. aureus as the sole pathogen were included. In individuals with a grade 1 ulcer, a second wound bacterial specimen was obtained 1 month later. Using oligonucleotide arrays, S. aureus resistance and virulence genes were compared between grade 1 and grades 2-4 ulcers. RESULTS: S. aureus was initially isolated from 22 grade 1 and 50 grade 2-4 ulcers: 35 were methicillin resistant and 37 methicillin sensitive. In 20 grade 1 ulcers (92%), no virulence genes were identified, whereas these genes were present in all but 1 grade 2-4 ulcers. During follow-up, the two grade 1 ulcers that were infected with strains carrying virulence genes rapidly deteriorated; the array technology showed unchanged genotype profiles. On the contrary, two grade 1 ulcers healed: the genotype profiles were different from those at inclusion but without appearance of virulence genes. CONCLUSIONS: The DNA array appears as a promising technique and is easy to perform. Our observational study suggests that it might help distinguish colonized grade 1 from infected grade 2 wounds, predict ulcer outcome, and contribute to a more adequate use of antibiotics.

CTX-M beta-lactamase-producing Escherichia coli in French hospitals: prevalence, molecular epidemiology, and risk factors.

In 2004, 65 CTX-M-producing Escherichia coli isolates were collected from infected patients in four French hospitals. The blaCTX-M-15 genes were predominant. Pulsed-field gel electrophoresis highlighted a clonal propagation of CTX-M-15-producing strains belonging to phylogenetic group B2, notably in the community. The main risk factors for acquiring these isolates were urinary tract infections or the presence of a urinary catheter in diabetic or renal failure patients.

qnrA in CTX-M-producing Escherichia coli isolates from France.

By PCR, we screened for qnr genes 112 clinical isolates of extended-spectrum beta-lactamase-producing Escherichia coli collected from hospitals in France during 2004. For the first time, 7.7% of CTX-M-producing E. coli isolates presented a plasmid-mediated resistance to quinolones. All strains harbored a qnrA gene located on a sul1-type class 1 integron with similar structure to the In36 integron.

First infection with VanD-type glycopeptide-resistant Enterococcus faecium in Europe.

We report the first strain of glycopeptide-resistant Enterococcus faecium from Europe that contains a vanD allele isolated from blood cultures of an immunocompromised patient hospitalized in a French university hospital. Based on phenotypic results, PCR sequencing, pulsed-field gel electrophoresis, and Southern blotting, the isolate was assigned to E. faecium with a chromosomally located VanD allele most closely related to the VanD1 allele.

Endocarditis due to a new rod-shaped Neisseria sp.

We report the first case of pacemaker endocarditis due to a new rod-shaped Neisseria sp. isolated from blood culture. On the basis of rrs sequencing, the isolate was found to be most closely related to an uncultured organism from human subgingival plaque and was identified as Neisseria sp. group AK105. A cure was achieved after a combination of surgical and antibiotic treatment. Oral flora-induced pacemaker endocarditis is a rare condition that reinforces the need for good oral hygiene as an important preventive measure.

Molecular epidemiology of Enterobacteriaceae isolates producing extended-spectrum beta-lactamases in a French hospital.

In 2002, 80 isolates of Enterobacteriaceae producing extended-spectrum beta-lactamases (ESBLs) were collected from infected patients in our hospital. Enterobacter aerogenes was the most common bacterium isolated from all specimens (36.5%). The ESBLs were predominantly (90%) TEM derivatives (TEM-24, TEM-3). Pulsed-field gel electrophoresis highlighted that E. aerogenes, Klebsiella pneumoniae, and Citrobacter koseri had a clonal propagation.

Spondylodiscitis due to Clostridium ramosum infection in an immunocompetent elderly patient.

The first ever case of spondylodiscitis caused by Clostridium ramosum in an elderly immunocompetent patient has been reported. C. ramosum is usually an intestinal bacterium but may occasionally be isolated in clinical specimens as an opportunistic pathogen. This report shows that this anaerobic organism can cause bone tropism without there having been any contamination due to spinal surgery. The infection cleared after empirical therapy using intravenous amoxicillin and oral metronidazole.