Gram Negative Bacteria in Indoor Environments
The designation of a bacterium as “Gram negative” is based on the reaction of the organism in the Gram stain test. This test quickly classifies bacteria into two categories based on the structure of their cell walls, which – in Gram negative bacteria – fail to retain a crystal violet stain because of their thin peptidoglycan layer.
The cell walls of Gram-negative bacteria consist of an outer membrane and a thin peptidoglycan layer which cannot retain the violet stain. This difference in cell wall structure translates into differences in how these organisms behave in the environment. Gram-negative organisms tend to be more vulnerable to drying due to their thinner cell wall, but less susceptible to cleaning agents as they possess an outer membrane that acts as a barrier to the uptake of sanitizers and disinfectants.
The concentrations of Gram-negative bacteria in indoor environments depend on a number of factors. These include the number and activity levels of individuals in the space, the types of clothing worn by individuals, the ventilation rate of the space, the presence of animals, and the presence of standing water.
In ISO-classified areas, the main source of microbial contamination is personnel and, to a lesser extent, materials transfer and infiltration of contaminated air.
Environmental laboratory testing of buildings, medical facilities, food preparation areas, and the like can aid in identifying threatening bacilli species and organism concentrations. Bacteria are hardy survivors and mainly pose risks where high bacterial loads of dangerous bacilli are present on surfaces or become airborne in public environments.
At U.S. Micro Solutions, our microbiology laboratory is a licensed, accredited source for thorough, cutting edge environmental testing, including USP 797, Legionella, indoor environmental testing, healthcare & medical testing, water analysis, and identification of specific pathogens. Visit our Laboratory Services page to learn more.
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