Characteristics of major Escherichia coli reductases involved in aerobic nitro and azo reduction.

AIMS: Escherichia coli is able to reduce azo compounds such as methyl red (MR) and nitro compounds such as 7-nitrocoumarin-3-carboxylic acid (7NCCA). The aim of this study was to clarify the specificity of the major E. coli reductases. METHODS AND RESULTS: Enzymatic assays with pure enzymes obtained after cloning, overproduction and purification under native or denaturing conditions were performed on three enzymes: AzoR, NfsA and NfsB. Their dependence on putative cofactors such as flavin mononucleotide (FMN), NADH and NADPH was studied as well as the reductase capacity of E. coli mutants depleted for one, two or three of the corresponding genes. CONCLUSIONS: AzoR was able to reduce both MR and 7NCCA, whereas NfsA and NfsB could only reduce the nitro compound. AzoR and NfsB were strictly FMN dependent in contrast to NfsA. At a low oxygen concentration, the three proteins were not mandatory for azo reduction and nitro reduction, but in optimal aerobic conditions, azoR was essential for MR reduction, and an nfsA/nfsB combination was important for 7NCCA reduction. Overexpression of azoR gene was able to compensate for the loss of nfsA and nfsB under aerobic conditions. SIGNIFICANCE AND IMPACT OF STUDY: These data provide new insights into the substrate specificity of major E. coli nitroreductases and demonstrate that oxygen is an important parameter to take into account in studies of nitroreductase activity.

Peri-prosthetic femoral fractures of hip or knee arthroplasty. Analysis of 34 cases and a review of Spanish series in the last 20 years. / Fracturas periprotésicas de fémur sobre prótesis de cadera y rodilla. Análisis de una serie de 34 casos y revisión de las series españolas en los últimos 20 años.

PURPOSE: To evaluate peri-prosthetic femoral fractures by analysing type of patient, treatment and outcomes, and to compare them with Spanish series published in the last 20 years. MATERIAL AND METHODS: A retrospective review of the medical records of patients with peri-prosthetic femoral fractures treated in our hospital from 2010 to 2014, and telephone survey on the current status. RESULTS: A total of 34 peri-prosthetic femoral fractures were analysed, 20 in hip arthroplasty and 14 in knee arthroplasty. The mean age of the patients was 79.9 years, and 91% had previous comorbidity, with up to 36% having at least 3 prior systemic diseases. Mean hospital stay was 8.7 days, and was higher in surgically-treated than in conservative-treated patients. The majority (60.6%) of patients had complications, and mortality was 18%. Functional status was not regained in 61.5% of patients, and pain was higher in hip than in knee arthroplasty. DISCUSSION: Peri-prosthetic femoral fractures are increasing in frequency. This is due to the increasing number of arthroplasties performed and also to the increasing age of these patients. Treatment of these fractures is complex because of the presence of an arthroplasty component, low bone quality, and comorbidity of the patients. CONCLUSION: Peri-prosthetic femoral fractures impair quality of life. They need individualised treatment, and have frequent complications and mortality.

Yeast identification--past, present, and future methods.

The focus of this review is the evolution of biochemical phenotypic yeast identification methods with emphasis on conventional approaches, rapid screening tests, chromogenic agars, comprehensive commercial methods, and the eventual migration to genotypic methods. As systemic yeast infections can be devastating and resistance is common in certain species, accurate identification to the species level is paramount for successful therapy and appropriate patient care.

[Value of media containing chromogenic substrates for the identification and the listing of urinary bacteria]. / Intérêt des milieux contenant des substrats chromogènes pour l'identification et la numération des bactéries urinaires.

Performance in terms of enumeration, growth and identification with a new culture medium (CPS ID2, bioMérieux) was evaluated using 405 urine samples and 244 collection strains. The CPS ID2 medium contains chromogenic substrates enabling the detection of 4 bacterial enzymes which leads to the identification of colonies: Escherichia coli, Proteus mirabilis, Proteus-Morganella-Providencia and enterococci. No discrepancies in the enumeration were observed with the collected strains and urine samples. Sensibility and specificity of the identification of Proteae taxa (TDA +) and enterococcal taxa (Gram positive cocci and beta-glucosidase +) was 100% using urine samples and 95.1% of E. coli strains (beta-glucuronidase +, indole +) are detected. Routine use of this new medium for the bacterial examination of urine is satisfactory and an ultra-violet lamp is no longer required for reading as was the case previously with media containing fluorogenic substrates.

Evaluation of CPS ID2 medium for detection of urinary tract bacterial isolates in specimens from a rehabilitation center.

CPS ID2 medium (bioMérieux) enables the presumptive identification of Escherichia coli and enterococci as well as the detection of indologenous or nonindologenous Proteeae and bacteria belonging to the Klebsiella, Enterobacter, and Serratia group with a specificity ranging from 98 to 100%. When the cultures were polymicrobial, the sensitivity varied from 70 to 97%, and the sensitivity varied from 97 to 100% when they were monomicrobial.

Evaluation of Candida ID, a new chromogenic medium for fungal isolation and preliminary identification of some yeast species.

Candida ID, a new chromogenic medium, allows identification of Candida albicans (blue colonies) and preliminary identification into a group of four species (pink colonies). In comparison with Albicans ID2 and Sabouraud gentamicin chloramphenicol on 446 fungal strains, Candida ID allowed the isolation of more species than Albicans ID 2 (95.5% versus 91.2%).