Enumeration of Viable Airborne Bacteria : Doubts about Membrane Filter Procedure

Effects of betaine on enumeration of airborne bacteria.

The osmoprotectant betaine was incorporated into collection fluid and enumeration medium to determine its effects on the colony-forming abilities of airborne bacteria, which were collected from three separate locations: a wastewater treatment plant, the roof of a laboratory building, and an unobstructed farmland. At all locations, addition of 2 to 5 mM betaine caused a significant increase (fro...

Membrane filter enumeration method for Clostridium perfringens.

A membrane filter procedure has been developed for the rapid quantitation of C. perfringens in the aquatic environment. Background growth is inhibited by the use of D-cycloserine, polymyxin B sulfate, and incubation at 45 degrees C. Differential characteristics include the fermentation of sucrose, production of acid phosphatase, and the absence of beta-D-glucosidase activity. The medium is prep...

The membrane filter technique for estimating numbers of viable bacteria: some observed limitations with certain species.

The membrane filter, also known as molecular filter, is valuable for its ability to permit passage of large volumes of fluid and yet retain on its surface particles of bacterial size. The history of its development and some of its properties have been reviewed by Goetz and Tsuneishi (1951). Other properties and specifications are available from the manufacturers.3 At present details of manufact...

Membrane filter-fluorescent-antibody method for detection and enumeration of bacteria in water.

A technique which employs nonfluorescing membrane filters and specific fluoresceinisothiocynate-labeled antiserum has been successfully used in the identification and enumeration of known species of Escherichia coli which have been added to natural populations of bacteria found in water. The quantitative results compared favorably with those of standard tests. The use of a dissecting microscope...

Doubts about dementia diagnoses.