We’re getting into the Christmas spirit here at 20/30 Labs, so we thought to put together a little Christmas post with a microbiological twist, our version of the Classic 12 Days of Christmas. There will be new content posted here every day, so be sure to check back in!

12 Drummers Drumming

Our “twelve drummers” here rocking the drums are the “superbugs” MRSA (Methicillin-resistant Staphylococcus aureus). MRSA is extremely difficult to treat, as it is resistant to beta-lactam antibiotics. MRSA is a particularly problematic in hospitals, prisons, and nursing homes as patients with open wounds and weakened immune systems are at greater risk of nosocomial infections compared to the general public.

On the eleventh day of Christmas my true love sent to me…

11 Pipers Piping

Several factors in pipework can influence the growth of both Legionella and Pseudomonas. Stagnant water favours bacterial growth, thus dead legs in pipework should be removed, and pipework should be kept as short and direct as possible. Legionella will proliferate rapidly between 20°C and 45°C, and when stagnant water is in this optimum range, biofilm formation is encouraged. Contamination can also be prevented by fitting water tanks with lids and insect screens. Other methods to control Legionella include copper and silver ionisation and biocide treatments (eg chlorine dioxide). To ensure that methods used to control Legionella remain effective their application will need to be assessed as part of the overall water treatment programme including proper installation, maintenance and monitoring.

On the tenth day of Christmas my true love sent to me…

10 Lords a Leaping

Carrying on our Christmas party theme, we found this picture appropriate for day 10. Did you know that 10 Lords a Leaping may refer to the Ten Commandments?

On the ninth day of Christmas my true love sent to me…

9 Ladies Dancing

For the 20/30 Labs Christmas party we went to an Italian Masquerade Party, and we were wowed by the exhilarating aerial acrobatics. With a superb four course dinner and a cocktail bar, we all loved it!

On the eighth day of Christmas my true love sent to me…

8 Maids a Milking

Milk Centrimide Medium is used for the presumptive identification of Pseudomonas aeruginosa from water and environmental samples. P. aeruginosa is identified by its green pigmentation with clear zones around the colonies. P. aeruginosa produces a number of water soluble iron chelators, including the yellow-green or yellow-brown fluorescent pyoverdin. Pyoverdin combines with the blue water-soluble pyocyanin, and the bright green colour characteristic of P. aeruginosa is created. P. aeruginosa is the only species of Pseudomonas or gram-negative rod known to excrete pyocyanin.

On the seventh day of Christmas my true love sent to me…

7 Swans a Swimming

Fresh water is host to numerous microorganisms that affect human health directly. Polluted drinking water is a major source of illness and death throughout the world. Some common microbes in lakes and streams that are responsible for disease include: Vibrio cholerae, which remains a significant source of disease and death in countries without advanced sewage treatment and with no potable water supplies. Escherichia coli, a common waterborne pollutant. Humans have a large, harmless population of E. coli in their intestines, and bacteria make up a large percentage of the volume of human faeces. When released into drinking water, E. coli can be ingested and enter the upper small intestine, causing diarrhoea.

On the sixth day of Christmas my true love sent to me…

6 Geese a Laying

Egg yolk is one of the reagents used in test soil, along with defibrinated horse blood and mucin from porcine stomach. Test soil is designed to mimic the soiling that naturally occurs on surgical instruments during theatre use. It is used to test washer disinfector machines to prove the efficacy of the machine by visually monitoring the residual soil left after a cleaning cycle. The protein in egg yolk is sticky and contains a lot of protein, thus making it a good ingredient to use in order to prove the cleaning efficacy of a washer disinfector. After all ingredients are mixed in the correct quantities, the test soil is gloopy and red/brown in colour.

On the fifth day of Christmas my true love sent to me…

5 Gold Rings

S. aureus appears as grape-like clusters when observed through a microscope, and has round, golden colonies, often with hemolysis, when grown on blood agar plates. S. aureus reproduces asexually by binary fission. The two daughter cells do not separate fully, therefore remaining attached to one another. This is why the cells appear in grape like-clusters.

On the fourth day of Christmas my true love sent to me…

4 Calling Bairds

Baird Parker Agar is now widely recommended by national and international bodies for the isolation of Staphylococcus aureus. Egg yolk emulsion makes the medium yellow and opaque. S. aureus reduces tellurite to form grey-black shiny colonies and then produces clear zones around the colonies by proteolytic action. On further incubation, most strains of S. aureus form opaque halos around the colonies. Not all strains of S. aureus produce both reactions. Some strains of Staphylococcus saprophyticus produce both clear zones and opaque halos but experienced workers can distinguish these from Staphylococcus aureus by the longer incubation time required. Several older versions of the song have “four colly birds” – “colly” being a regional English expression for “black”, just like our Staph!

On the third day of Christmas my true love sent to me…

3 French Hens

Brewing is the production of beer by steeping a starch source in water and fermenting the resulting sweet liquid with yeast. Fermentation is a metabolic process that converts sugar to acids, gases and/or alcohol. It occurs in yeast, bacteria, cancer cells but also in oxygen-starved muscle cells. Bottom-cropping yeasts are normally used to produce lager-type beers, though they can produce ale-type beers. These yeasts ferment well at low temperatures. An example of bottom-cropping yeast is Saccharomyces pastorianus, formerly known as S. carlsbergensis, (guess why!).

On the second day of Christmas my true love sent to me…

2 Turtle Doves

If you touch a turtle, wash your hands! Reptiles such as turtles, snaked and lizards are becoming more popular as pets, however they carry bacteria called Salmonella on the outer skin and shell surfaces. Symptoms of being infected with Salmonella can include diarrhoea, fever, stomach pain, nausea, vomiting and headache. In rare cases, it can be life threatening.

Image Credit: http://meteor-panda.deviantart.com/art/Turtle-Dove-214350431

On the first day of Christmas my true love sent to me…

A Partridge in a Petri

If you’ve seen our Halloween blog post, you’ll know we love cheesy puns… MLGA (Membrane Lactose Glucuronide Agar) is a medium used to differentiate and enumerate E. coli and other coliforms by membrane filtration. E. coli colonies appear green on this medium due to biochemical reactions that occur during its growth on this medium. Our E. coli was incubated at 37°C for 20 hours. Testing potable water for the presence of coliforms and E. coli is crucial as their presence is indicative of faecal contamination.