Microbial Identifications & Strain Typing

In the manufacturing process, microbial contaminants may be originated from many different locations and sources, including human handling, air/ particulate matter, water, contact with surfaces, raw materials, and even the final product. STEMart offers the most accurate results due to medical device industry-relevant microbial databases and trending data solutions.

Both the ISO 11737, the USP <61>, USP<71> give out guidance for accomplishing a Microbial Identification by a pure culture with a "successive streaking of the colony of interest in a quadrant pattern." The Microbial Identification tests are performed after the bioburden testing, environmental monitoring, tissue testing, microbial limits, and BI with positive results.

Identification methods

• Gram staining

Gram staining is generally the first required test in bacterial identification. Isolated colonies are examined for colony morphology, Gram reaction, and cell morphology in this procedure. This purple stain that based upon the crystal violet dye is named after the Danish bacteriologist Hans Christian Gram, who developed it. Typical Gram-positive bacteria include Bacillus, Staphylococcus, Streptococcus, and Clostridium spp. while Escherichia, Helicobacter, and Salmonella spp which are Gram-negative. It should be taken into account that since certain bacteria are Gram-variable, they are not amenable to Gram staining.

• Genetic Identification

Genetic Identification is generally performed along with Gram stain. The purpose is to ensure a pure culture and to further determine the unknown organisms belong to bacteria or yeast. This also provides phenotypic component information which makes the identification more complete. Genetic Identification uses DNA instead of traditional biochemical reactions. DNA is isolated from the culture, and the fragment of the 16S rDNA gene is amplified by PCR, by the way, the PCR amplicon will be purified to remove contaminants. Then sequencing and comparing the unknown sequence to the MicroSeq library. If a match is not found in the MicroSeq library, a public database may be searched. The first ten sequences are selected based on the maximum identity score.

STEMart's Microbial Identifications & Strain Typing services offer unparalleled accuracy with the most relevant reference libraries of bacteria, filamentous fungi and yeasts. Our Microbial Identifications & Strain Typing services allowing your lab to take advantage of the latest identification and typing methods to fully characterize isolates, without the need for capital investment and staff training.

If you have additional questions about Microbial Identifications & Strain Typing or would like to find out more about our services, please feel free to contact us.