Colony Forming Unit

Low and high refer to the number of colony forming units (CPU) used to inoculate the media. Comparing MICs at low (10 ) and high (10 ) CPU, a large increase in MIC at the high inoculum level vs a P-lactamase producer is an indicator of instability via enzymatic hydrolysis. 

All counts expressed as colony-forming units per milliliter or gram. 

Summation of mesophilic bacteria, fungi, and thermophilic bacteria. CPU = colony-forming units. 

CFXI Viable micro-organisms (bacteria, yeasts mould) capable of growth under the prescribed conditions (medium, atmosphere, time and temperature) develop into visible colonies (colony forming units) which are counted. The term colony forming unit (CPU) is used because a colony may result from a single micro-organism or from a clump / cluster of micro-organisms. 

E.coli recA y.luxCDABE strain were grown for 16-18 hours at 37°C in LB-broth in the presence of 20 pg/ ml of ampicillin. Immediately before the experiment the culture was diluted 1 20 by fresh culture medium and incubated until early log-phase. The grown biomass was mixed with AR solutions in final concentrations of ICfs, ICH n ICfs M, with used for their dilution with distilled water (control) and incubated for 60 minutes. The luminescence intensity of UV-irradiated E.coli recA lux and intact specimens were registered by plate bioluminometer LM OIT (Immimotech, Czech Rep.) in a real time. The number of viable cells was determined from the colony-forming units (CFU) on a surface of a LB-agar after the subsequent incubation within 24 hours at 37 °C. A quantitative estimation of an induction of the SOS-system calculated on formula... 

A number of biochemical markers not associated with the cell envelope allow the specific detection of individual microorganisms in environmental samples. These include secondary alcohols. For example, Mycobacterium xenopi can be detected through the hydrolysis of wax ester mycolates, which liberates 2-docosanol, a characteristic and dominant secondary alcohol, which can be detected at low levels by GC-MS. This biomarker was found to be very useful for the rapid detection of M. xenopi in drinking water (159,160). Results from the GC-MS detection of 2-docosanol were obtained within 2 days compared to the 12 weeks required for culturable detection of M. xenopi. The detection limit for this type of approach was found to be 10 colony-forming units (CFU) ml" drinking water. 

Erythropoiesis is a process that starts with a pluripotent stem cell in the bone marrow that eventually differentiates into an erythroid colony-forming unit (CFU-E)4 (Fig. 63-1). The development of these cells depends on stimulation from the appropriate growth factors, primarily erythropoietin. Other cytokines involved include granulocyte-monocyte colony-stimulating factor (GM-CSF) and interleukin 3 (IL-3). Eventually, the CFU-Es differentiate into reticulocytes and cross from the bone marrow into the peripheral blood. Finally, these reticulocytes mature into erythrocytes after 1 to 2 days in the bloodstream. Throughout this process, the cells gradually accumulate more hemoglobin and lose their nuclei.4... 

The infectious dose of EHEC is very low, between 1 and 100 colony-forming units (CFUs).15 The two major virulence factors... 

CFU colony-forming units CrCl Creatinine clearance SCr Serum creatinine... 

Colony-forming units The number of microorganisms that form colonies when cultured indicates the number of viable microorganisms in a sample. 

Samples were cultured for 10 days and results expressed as colony forming units per litre (cfu/1)... 

In a parallel test with water instead of disinfectant the colony forming units (cfu) of surviving bacteria are determined and the reduction in viable counts is calculated. 

Duplicate counts are made using serial dilutions up to 10-6 and drop plates. Solutions are then spotted onto blood agar plates and incubated at 37 °C for 18 hours after which the number of colony forming units is determined. To pass the BA Challenge Test there must be no growth from the aliquots taken at 15 minutes or more from the 1 400 and 1 1600 dilutions. 

Analysis of table two shows that a staphylococcus aureus count of 1 million colony forming units per gram was killed off on plate within 5 to 15 minutes using very high levels of antimicrobials at a level only suitable for feet application whereas the Myavert C in the face mask achieved the same level of kill within three minutes, yet it is very mild and suitable for face and eye area application. Three minutes and longer application time for a product such as face is mask is common and this would achieve normal cleansing as well as microbiological purification of the face of the customer. 

Surface Monitoring Contact (or Rodac) plates of growth media are applied to surfaces such as bench tops, walls, and personnel and then incubated. Colony-forming units (cfu) are counted and identified. 

The most common criticism of whole-cell MALDI is that the method requires a relatively large number of cells, usually obtained directly from culture media. In principle, an analysis of even a few unknown bacteria (a colony-forming unit) is possible after a culture step. More important is the number of bacteria needed in a sample or on the sample probe for successful analysis. Detection of a very small number of bacteria could eliminate the need for a preliminary culture step. This would be a considerable asset for environmental analysis (unless to many bacteria were detected) and for the detection of a bioterrorism-related release of bacteria. 

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