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Microbiology Laboratory

 The Microbiology Laboratory studies biology on a very small scale. Testing is performed on a large variety of specimens including urines, blood, throat swabs, faeces, wound swabs and sterile body fluids. Our primary focus is on bacteria but we also handle the testing for other microorganisms that may contribute to human illness, including myoplasmata, viruses, fungi, and intestinal parasites. Along with the specimens from RVH, we also process all the specimens from Midland and Penetanguishene (the North Simcoe Health Alliance) and from Alliston’s Stevenson Memorial Hospital.


All specimens arriving in the Microbiology Laboratory are logged into the computer. They then go into a Biosafety cabinet for “planting” onto specially formulated media in petri plates. There are many types of media, all of which serve a specific purpose. For example, sometimes there is the need to discourage growth of normal flora (bacteria present in organs of the body normally), so that a pathogen (disease-causing organism) can get noticed, and conversely, some pathogens are very delicate and need special growth factors to assist them in their growth. Most petri plates are incubated (stored in a warm cabinet) overnight at human body temperature. The air atmosphere in the incubator is suited to the type of organism that we might expect to encounter. Many bacteria prefer an increased level of carbon dioxide rather than normal air, and some prefer anaerobic (oxygen-free) conditions. What the organism likes depends on what part of the body the organism prefers to live in.

Once we identify a human pathogen, we perform “susceptibility testing” to determine which antibiotics will effectively kill it. This involves testing the pathogen against a wide selection and concentration of antibiotics in order to give the clinician choices for treatment. In our laboratory, much of the identification and susceptibility testing is performed using an instrument that compares the reactions of each pathogen being tested against a large database for comparison.


One of the most important tests performed by the Microbiology Laboratory is called the "Gram stain". This staining method stains bacteria either pink (which is called gram negative) or purple (which is gram positive). As well, we can see whether organisms are round (cocci) or rod-shaped (bacilli). The stain takes minutes to perform, and gives the physician vital clues regarding the ultimate identification of the organism.

Microbiology performs routine screening for several “superbugs” including Methicillin - resistant Staphylococcus (MRSA) and Vancomycin - resistant Enterococci (VRE). We do a variety of “rapid” tests, notably for Strep throat, Influenza and Respiratory Syncytial virus. We also perform testing for Clostridium difficile.

The Microbiology Laboratory is in daily contact with the Infection Prevention and Control department of the hospital. Infection Prevention and Control is notified of all pathogens that could be public health concerns or that were acquired in the hospital so that appropriate actions may be taken to eliminate these infections. The Pharmacy often consults with Microbiology to discuss options for treatment when a patient has allergies to some drugs or if an organism is resistant to many antibiotics. We also receive calls for advice from some of the smaller Microbiology Laboratories in Simcoe County. Microbiology is involved in several studies that track susceptibility patterns of common pathogens across Ontario and nationally.


Phone: 705-728-9090 Ext. 43271