ABSTRACT
BioArgos (Sanofi Diagnostics Pasteur, Marnes-la-Coquette, France) is a fully automated blood culture system that detects carbon dioxide production by infrared spectroscopy through a glass bottle. This hands-off system was compared with the BACTEC NR-660 system (Becton Dickinson Diagnostic Instrument Systems, Towson, Md.). A total of 336 microorganisms belonging to 74 taxa were tested in simulated blood cultures by both systems. Experimental data showed no significant differences between the two systems. The inclusive detection times (+/- the standard deviations) were 33.2 +/- 28.7 and 35.0 +/- 30.6 h with BioArgos and BACTEC, respectively. Anaerobes were detected earlier with BioArgos, whereas detection of some organisms that need oxygen to grow was slightly delayed. In conclusion, BioArgos is as reliable and accurate as BACTEC NR-660 and shows better practicability owing to noninvasive detection, reduction of vial manipulation, and absence of daily maintenance.
Subject(s)
Bacteriological Techniques , Blood/microbiology , Aerobiosis , Anaerobiosis , Bacteriological Techniques/statistics & numerical data , Evaluation Studies as Topic , Gram-Negative Bacteria/isolation & purification , Gram-Positive Bacteria/isolation & purification , Humans , Mycology/methods , Sensitivity and Specificity , Yeasts/isolation & purificationABSTRACT
An investigation was made of the survival of six strains of Rhizobium meliloti filtered on membrane filters and held in atmospheres of controlled relative humidities (RH) of from 0 to 100% at 30 degrees C in the presence of air. The rate of water loss in the desiccator was determined by the humidity-controlling solution used. Drying was accelerated by a mild evacuation of the desiccator during the drying step. Survival rates of R. meliloti strains were much higher after slow drying to 0% RH than immediately after rapid drying. Fast drying (drying period less than 3.4 h) was shown to adversely affect the tolerance to storage at all RH values tested (no survival after 2 to 5 days of storage). When survival during storage was measurable (after slow drying), the optimum RH values for storage were 43% for strains A145 and Wu498, 22 to 43% for strains RCR2011, Wu499, and Ar16, and 83% for strain RCR2004. The most favorable drying periods were 8, 9.2, 14.2, and 50.1 h for the subsequent storage of strain RCR2011 at RH values of 0, 22, 43, and 83%, respectively. The damaging effects of rapid drying on the tolerance of strain RCR2011 to storage at different RH values could be prevented either by rehydration and subsequent slow redrying or incomplete rapid drying followed by slow drying. It is suggested that R. meliloti strains are susceptible to desiccation stresses. However, the quantitative differences among strains appear to be large enough to permit selection with regard to tolerance to desiccation and storage in dried states.
ABSTRACT
Micro-ID system is a new identification kit for Enterobacteriaceae which provides the identification at the species level 4 hours after primary isolation. When compared with conventional biochemical tube media, micro-ID gave a 94% agreement. Comparison of Micro-ID with Api 20 E showed a 90% agreement. A comparison of all 3 systems showed that for 90% of the time, the isolates were named the same by the all systems.
