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Northeast Laboratories, Inc.

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Berlin Office
129 Mill Street, Suite 11
Berlin, CT 06037
CT 860.828.9787 or 800.826.0105
outside CT 800.654.1230
fax 860.829.1050
Contact the Berlin Office

Microbiology Interpretations

Aerboes : Organism capable of growth only when exposed to air.

Anaerobes : Organisms capable of growth only when not exposed to air.

Enterococcus bacteria : The enterococcus group is a subgroup of the fecal streptococci that includes S. faecalis, S. faecium, S. gallinarum, and S. avium.

The enterococci portion of the fecal streptococcus group is a valuable bacterial indicator for determining the extent of fecal contamination of recreational surface waters.

Studies at marine water bathing beaches indicated that swimming-associated gastroenteritis is related directly to the quality of the bathing water and that enterococci are the most efficient bacterial indicator of marine water quality.

Gram-positive and Gram-negative bacteria : The many thousands of known bacterial species have traditionally been classified into two very large groups on the basis of their reaction to Gram Staining. Species which retain a violet coloration despite washing with alcohol are said to stain Gram-Positive; species which lose the violet coloration with alcohol washing and may be counterstained with a contrasting dye, such as safranin, are said to stain Gram-negative.

Gram staining characteristics appear to be related to structural or metabolic properties of the species, and this characteristic serves as a rapid and very basic step in the identification of the species.

Gram Positive Bacteria - are generally susceptible to basic dyes; their isoelectric point is about pH 2; and, most important, they are generally more susceptible to antimicrobial agents than Gram-negative species.

  • Some of the more common Gram positive bacteria include: Bacillus, Clostridium, Listeria, Staphylococcus, and Streptococcus.

Gram Negative Bacteria : are sensitive to acid dyes; their isoelectric point is about pH 5; and, except for the cocci in this grouping, they are generally less sensitive than the Gram-positive bacteria to antimicrobial agents.

  • Some of the more common Gram negative bacteria include: Enerobacter, Klebsiella, Escherichia (including E. coli), Hemophilus, Pseudomonas, Salmonella, and Shigella.

Pathogens : Disease causing bacterium or fungus.