International dissemination of Escherichia coli strains with discrepant behaviour in phenotypic antimicrobial susceptibility tests.

Preventing the dissemination of antimicrobial resistance depends on appropriate antibiotic stewardship and accurate antimicrobial susceptibility testing (AST). We report the international dissemination of Escherichia coli strains, showing discrepancies between reference methods when phenotypically tested for susceptibility to piperacillin/tazobactam (TZP). We demonstrate that these related strains are predisposed to problematic TZP AST interpretations.

Rapid clinical bacteriology and its future impact.

Clinical microbiology has always been a slowly evolving and conservative science. The sub-field of bacteriology has been and still is dominated for over a century by culture-based technologies. The integration of serological and molecular methodologies during the seventies and eighties of the previous century took place relatively slowly and in a cumbersome fashion.

Respiratory virus infections in adults with hematologic malignancies: a prospective study.

During a 2-year period, 157 consecutive episodes of respiratory virus infections that occurred in 130 patients with upper or lower respiratory tract infection were analyzed for respiratory viruses. A respiratory virus was identified in 75 episodes (48%), and several viruses were found in 13 episodes: there were a total of 56 influenza A virus infections, 14 respiratory syncytial virus infections, 8 adenovirus infections, 8 infections with parainfluenza virus types 1 or 3, and 7 enterovirus infections. On multivariate analysis, the only variable that predicted progression to pneumonia in patients with an upper respiratory tract infection was the presence of respiratory syncytial virus, whereas lymphocytopenia had a nonsignificant trend.

Predictive factors for a successful mobilization of peripheral blood CD34+ cells in multiple myeloma.

We analyzed the prognostic factors for a successful mobilization and peripheral blood stem cell collection in a series of 57 consecutive patients with multiple myeloma (MM); a new scoring system to predict an adequate mobilization in this subset of patients was also constructed. A total of 221 aphereses were performed in 57 patients with MM. The median time from diagnosis to mobilization was 12 months (range 4-120).

Potential impact of the VITEK 2 system and the Advanced Expert System on the clinical laboratory of a university-based hospital.

A study was designed to assess the impact of the VITEK 2 automated system and the Advanced Expert System (AES) on the clinical laboratory of a typical university-based hospital. A total of 259 consecutive, nonduplicate isolates of Enterobacteriaceae members, Pseudomonas aeruginosa, and Staphylococcus aureus were collected and tested by the VITEK 2 system for identification and antimicrobial susceptibility testing, and the results were analyzed by the AES. The results were also analyzed by a human expert and compared to the AES analyses.

Ability of the VITEK 2 advanced expert system To identify beta-lactam phenotypes in isolates of Enterobacteriaceae and Pseudomonas aeruginosa.

The Advanced Expert System (AES) was used in conjunction with the VITEK 2 automated antimicrobial susceptibility test system to ascertain the beta-lactam phenotypes of 196 isolates of the family Enterobacteriaceae and the species Pseudomonas aeruginosa. These isolates represented a panel of strains that had been collected from laboratories worldwide and whose beta-lactam phenotypes had been characterized by biochemical and molecular techniques. The antimicrobial susceptibility of each isolate was determined with the VITEK 2 instrument, and the results were analyzed with the AES to ascertain the beta-lactam phenotype.

Allogeneic or autologous stem cell transplantation following salvage chemotherapy for adults with refractory or relapsed acute lymphoblastic leukemia.

Over a 9-year period 37 consecutive adults with primary refractory (n = 13) or first relapse of ALL (n = 24) received an intensive salvage chemotherapy regimen with the final intention of undergoing stem cell transplantation (SCT). Twenty-nine patients who achieved complete remission (CR) were assigned to receive autologous SCT (autoSCT) or allogeneic SCT (alloSCT) based on age and availability of a histocompatible sibling. Of the 19 patients assigned to autoSCT, 10 did not reach the transplant due to early relapse (n = 9) or fungal infection (n = 1), and nine were transplanted a median of 2.

Evaluation of an expert system linked to a rapid antibiotic susceptibility testing system for the detection of beta-lactam resistance phenotypes.

Interpretive reading of antibiotic disc agar diffusion tests indicates the resistance mechanisms, if any, expressed by a bacterium. An expert system for determining resistance mechanisms using rapid automated antibiotic susceptibility tests has been developed. The beta-lactam susceptibility of each of 300 strains of clinically significant species of enterobacteria, displaying natural and acquired resistance mechanisms, was determined by disc agar diffusion and by a rapid automated method of susceptibility testing associated with an expert system.

[Detection of the phenotypes of resistance of enterobacteriaceae to aminoglycosides with ATB Plus Expert System].

ATB Plus Expert (Biomérieux SA) is an expert system which has been developed to perform an interpretative reading of ATB susceptibility tests. The system was tested on the results obtained for 217 strains of enterobacteriaceae. These strains were selected in order to cover a maximum of bacterial species and resistance mechanisms.

Determination of MICs for staphylococci using the API ATB quinolone and API ATB macrolide systems.

The determination of minimal inhibitory concentrations (MICs) is cumbersome, but remains necessary in certain cases. We tested the two ATB MIC experimental strips (Biomérieux SA), of which each contains 4 antimicrobials of the same class. These strips can be read automatically.

[Time-killing curves of Pseudomonas aeruginosa strains exposed to polymyxin B].

The time-killing curves of three strains of Pseudomonas aeruginosa (PA01, ATCC10145 and ATCC27853) exposed to five concentrations of polymyxin B comprised: a latency phases, one or two decreasing phases and for the low polymyxin B concentrations a growth phasis. The five antibiotic concentrations were chosen to have a weak bactericidal effect such that decreasing exponential or biexponential models can be fitted to the data. In our experimental conditions, increasing Ca++ and Mg++ concentrations in the medium (Mueller-Hinton) reduced the bactericidal effect and increased the growth phases.

[Influence of the culture medium (Isosensitest or Mueller-Hinton) on the results of antibiotics susceptibility testing and its interpretation].

The individual results of the antibiotic susceptibility tests of 110 Enterobacteriaceae to 31 antibiotics (beta-lactamines, aminoglycosides, quinolones) have been compared on Mueller-Hinton and Isosensitest. No difference between the diameters of inhibition has been shown by the paired t test or signed rank test. The identification of the phenotypes of resistance (resistance patterns) were compared by principal component analysis and by help of an expert system.

[Mathematical study of the sensitivity curves of Escherichia coli exposed to polymyxins].

The time killing curves of five strains of Escherichia coli (ATCC 25922, ATCC 29194, CIP 54125, CIP 54127, CIP 54117 (K 12)) exposed to five concentrations of polymyxin B are similar: latency phasis, two decreasing phasis and for the low polymyxin B concentrations growth phasis. In our experimental conditions, the Mg(+)+ and Ca(+)+ concentrations of the medium (Mueller-Hinton; medium A: Ca(+)+ = 9 mg/l, Mg(+)+ = 0.5 mg/l; medium B: Ca(+)+ = 35 mg/l, Mg(+)+ = 15.

Determination of G + C content of DNA using high-performance liquid chromatography for the identification of staphylococci and micrococci.

The guanine-plus-cytosine (G + C) content of different species of Staphylococcus and Micrococcus was determined by high-performance liquid chromatography. Purified bacterial DNA was hydrolysed by nuclease P1. The nucleotides were separated by chromatography and quantified by measurement of the optical density at 260 nm.

[Interpretative reading and quality control of an antibiotic sensitivity test using an expert system. Application to the API ATB system and Enterobacteriaceae].

An expert system (cadi-yac), written in Turbo-Prolog and working on IBM PC and Bacanal + (a management software of microbiology laboratory) was used to recognize and correct the phenotype of antibiotic sensibility. The results were there of API ATB system. The knowledge was adapted from two references works.

[Demonstration of an inoculum effect on the estimation of the minimal inhibitory concentration of LY 146032].

This work has been performed to study the inoculum effect on the in vitro activity of LY 146032, a new lipopeptide antibiotic. A statistical analysis (X2 and t test) of the data concerning the MIC of different bacterial groups has been carried out to appreciate the phenomenon. The activity of vancomycin has been compared.

[Bullous muco-synechial dermatitis atrophicans. Development and current nosological status].

The authors report six cases of cicatricial pemphigoid emphasizing the initial sintoms and signs of the disease and its ocular localization in order to make an early diagnosis and an efficient therapeutic control; so as to avoid the cicatricial complications. From the therapeutical point of view me propose the use of local therapy and permanent contact lenses.