Analytical Services

SMI offers an extensive array of environmental microbiology testing services.  A partial listing is presented below.   SMI is heavily invested in the development of innovative methods for the detection of pathogenic microbes as well as indicator microorganisms.  SMI also offers custom research support.  Please contact our Project Management team to discuss how SMI can

support your specific research needs.

Detection of Enteric Viruses

Viruses are obligate intracellular parasites that cannot multiply outside of specific host cells.  In

the case of human enteric viruses, testing services for culturable viruses generally rely upon mammalian cell cultures following filter-based sample concentration.  SMI offers an array of analytical services for the detection of waterborne viruses that extends far beyond those you will

find in commercial testing laboratories.  SMI scientists have decades of experience with the application of mammalian cell cultures but has extended the capacity for culturable virus testing

to include ultrasensitive RNA and DNA-based methods that rely upon enzymatic amplification techniques such as the Polymerase Chain Reaction.

Our central analytic facility maintains an assortment of primate-derived cell cultures for the

detection of enteric viruses according to the USEPA ICR method, and has coupled these

methods with PCR techniques to offer Integrated Cell Culture PCR (ICC-PCR) testing services. 

SMI can not only determine the levels of culturable viruses in your samples, but can apply hybridization screening to determine the virus species present.  Contact our Project

Management team to discuss how SMI can address your virus testing needs.

Emerging Contaminants - EPA Contaminant Candidate List 2 (CCL 2)

The USEPA has listed several viruses on the Contaminant Candidate List 2.  SMI is researching analytical techniques for detecting several members on the current list and SMI scientists have facilitated workshops convened by the USEPA and the American Water Works Association to determine national research priorities for the microorganisms currently listed.  SMI currently employs an array of biotechnologies aimed at developing improved virus detection techniques, including isoelectric focusing, microfluidics and innovative concentration procedures relying upon positively charged filters (ViroCap™).

Genotyping of Male-Specific Coliphages Into Four Geno-Groups

Coliphages are bacterial viruses that reproduce within the coliform group of bacteria.

"Male-specific" coliphages represent a subset that bind to the physical appendages expressed

only by male strains of E. coli and that are used during the process of sexual conjugation by bacteria during the exchange of genetic information.  The utility of using male-specific coliphages as water quality indicators revolves around the fact that these pili are expressed only by male strains of bacteria and only under conditions of elevated temperature - conditions that are consistent with the environment of the mammalian gastrointestinal tract.  Hence, the presence of these coliphages is more likely to be associated with the presence of fecal contaminants that arise from the deposition of warm blooded animals.  Environmental surveys have produced occurrence data that indicate improved correlations between male-specific coliphages and the presence of human enteric viruses; moreover, some of these studies have demonstrated that human enteric viruses may be present in waters that are meeting bacterial coliform standards.  Coliphages are listed in the EPA's draft Groundwater Rule as viral indicators for compliance monitoring.

SMI scientists have extensive experience in the study of coliphages as microbiological indicators and were instrumental in the development of the methods currently approved by the USEPA for detecting coliphages in water.  As part of its ongoing research mission, SMI has extended the

utility of these methods to further classify coliphage isolates into genogroups associated with specific human or animal hosts.  SMI can now perform specific tests to identify the strains of coliphages that are present in source waters so that its clients can characterize the origin of fecal pollutants impacting a water body.

Coliphage Source Tracking by Oligoprobe Hybridization

Coliphages isolated from water sources can be enumerated using techniques such as USEPA Method 1602.  However, this method does not provide detailed information on the host organisms that originally excreted the microorganisms.  SMI has extended the utility of the traditional enumerative methods for detecting coliphages by commercializing molecular techniques that

can classify coliphage isolates into prototype genogroups.  The genetic material extracted from coliphage isolates is hybridized to one of several short labeled sequences of synthetic DNA that

are labeled enzymatically.  The bound viral nucleic acids are then visualized colorimetrically to distinguish the different genogroups.  Binding signatures make it possible to classify virus

isolates into one of four distinct coliphage groups.  Coliphages that correspond to human feces

are statistically associated with phage groups 2 and 3, whereas animal coliphages are

associated primarily with phage groups 1 and 4.  By performing this genogrouping technique,

SMI can classify fecal pollutants as originating from animal or human sources.

Depending upon the data requirements of the project, a defined number of male-specific

coliphage isolates from water samples can be subjected to hybridization analyses.  Please

contact a project manager for inquiries on how we can assist you for your source tracking project using coliphage genotyping.

For further information about SMI's services, please feel to contact a project manager at (574) 277-4078.