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
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
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