Excellent Week in Lab

This whole week went as planned because I was right on schedule for sampling my objects around campus. Figure 1 below shows few places that was sampled in the Hannelly Center. The small side table tops attached to the chairs was sampled. The table below figure 1 shows the related colony forming units (CFU).                                                                                               

Figure 1. The red oval shaped areas are the general idea of where the sampling took place at.

Figure 2 and 3 below show the keyboard and mouse that was sampled in the library on the lower level of student resources for computer use.

Figure 2. The original sampling was on the "space bar" but the area was too small for the contact plates, so each plate was firmly pressed on half of the contact plate and the above picture shows the idea of how it was sampled.

Figure 3. Some mouse were sample twice and some where sample just once on the top with a rocking motion. If another plate was to be sampled on the same mouse, then half of it was sampled on the sides of the mouse.

The Bear Cave Cafeteria was, also, sampled around dinning area. Furthermore, the table tops were observed by myself of a cashier wiping down the tops with a rag. Thus, the colony plate count should be low, but I believe the microorganisms were just moved around.

Figure 4. The area of eating in the cafeteria.

Organized and Ready

I started this week off with a great start. I have a good amount of contact plates with no problems of loss of inventory. I prepared about six sleeves of 20 plates this week. Figure 1 below shows the progress of perfect dome shaped above the rim of the plates being prepared. I modified the dispensing of 17mL to 16mL because of the overflow and loss of plates.

Figure 1. The plates are being UV for further sterilization.

Figure 2. The numbers correspond to the table 1 below of total Colony Forming Units.

Plate #	Total CFU	Plate #	Total CFU	Plate #	Total CFU	Plate #	Total CFU
1	89	6	82	11	54	16	19
2	6	7	98	12	47	17	31
3	19	8	65	13	31	18	29
4	49	9	62	14	26	19	12
5	30	10	39	15	18	20	35

I, also, sampled the plates on two locations around campus. The first location was room 221 of the DB building on the second floor. Figure 2 above shows the area being monitored for fomites and the corresponding plates to CFU’s. I noticed that as you move from the back to the front of the room the CFU's get smaller per plate.

Lesson Learned

I started to pour the agar using a Multipipette Plus with a 50 mL syringe for a total volume of 17 mL added to each empty contact plate. I did some research on the plates and found there name to be known as RODAC (Replicate Organism Detection and Counting) plates. The supplying company recommended filling the plates on their website between 16.5-17.5 mL for proper convex surface to be achieved. The figure below shows some of my flaws conducted Monday in the flow hood. 

 

Figure 1. The spill was so quick and sensitive to touch that the cohesion of any surface quickly pulled it over the lip or ring around the top.

Figure 2. The plates were left in the hood for 10 minutes with the ultraviolet light on for proper sterilization.

 

The contact of the lid and liquid caused multiple spillage and contamination. The first thing I need to work on is conserving the empty plates by making no mistakes for contamination. Thus, there will be no waste of agar and RODAC plate inventory. Furthermore, I need to be more quick, efficient, and organized. I, also, noticed on Monday that the plates need to cool without the lids. Dispensing the warm TSA liquid from the pipette needs to be quick in regards to time because of the solidification of the Multipipette syringe.

Figure 3. This shows the muffin top like shape of the solidified tops of these contact plates.

Late Start

I started my hours for the internship this week on Friday. On the other hand, I decided to continue my project with an easier step of obtaining samples. I will prepare my own agar for pouring into contact plates which will eliminate the hassle of the “swabbing method.” The contact plates are miniature plates with a molded grid on the bottom of this bulb like surface. I plan to prepare and pour the agar after the thirty minute water bath from the autoclave. Figure 1 below shows three empty contact plates and the Pipet used during the filling of these plates. 

 

Figure 1. The bottom isn't flat like other plates, but it has like a bulb like surface. The Pipet is used for multiple dispensing of efficient volume because the maximum volume is 17 ml.

 

Figure 2. The agar is slightly above the rim of the plate for making contact with surfaces of objects.

Figure 2 shows the finished product of an elevated agar to make direct contact with surfaces around campus. I was going to use the dispenser machine, but the mentors noted that the dispenser is outdated. I look forward to next week. I, also, took a picture of the dispensing machine below in Figure 3.

Figure 3. I always saw this machine but never new what it did until today.