"Danger! Watch yourself!" Lab Safety Practices

With all the news concerning poor laboratory practices, such as the CDC anthrax incident and finding cultures of various diseases in storage closets, emphasis on proper safety in the laboratory environment is essential.

In any medical laboratory environment, there are inherent dangers which can be increased unnecessarily by poor safety protocols and practices.  As with any job or daily routine, a level of familiarity can lower one’s guard and open the door for potentially serious outcomes.

Here is a list, that may seem common sense and second nature to a laboratorian, which if followed could prevent many of these opportunities for danger.

1.      Treat every sample as a potentially dangerous pathogen.

Any sample that comes through a medical laboratory could contain any virus, bacteria, fungus, or parasite and should be processed with this kept in mind.

 

2.      Sterilize all equipment and properly discard contaminated materials

This serves the purpose of preventing cross contamination between samples or accidental exposure and keeps the work area uncluttered.

 

3.      Disinfect work spaces before and after use

This follows along with the previous rule, keeping the work space clean.

 

4.      WASH YOUR HANDS!

This is probably the easiest yet most important rule on this list.  The significance of proper hand washing technique and frequency is fundamental to lab safety.

 

5.      Never mouth pipette

This sounds very strange, but only 20 to 30 years ago, this was a common practice.  Now it has been phased out for the most part, but still worthy of mention for obvious reasons.

 

6.      No food or drinks in the laboratory

This is another rule that could become abused in the everyday workplace due to the daily routine.

 

7.      Clearly label everything

This practice could prevent accidental exposures do to treatment of a dangerous substance with insufficient safety protocols, and keeps everyone informed and on the same level as far as samples and reagents being used are concerned.

 

8.      Autoclave any contaminated materials

As with suggestions 2 and 3, the proper discarding of used materials which have been exposed to hazardous substances or dangerous pathogens is crucial in keeping what is in the lab from harming others.

 

9.      Follow proper procedures for spills and/or exposures

Any laboratory has strict protocols and procedures already set in place for any potential spills or exposures which could occur within the laboratory environment.  These preplanned actions are meant to minimize the risk of these hazardous events if they do occur.

 

Although a certain level of familiarity, comfort, and routine is expected in any workplace environment, it is the responsibility of everyone involved to be both vigilant and actively participate in the prevention and implementation of safety in the laboratory environment.

 

(The main bullet points where derived from a list from an article by Daniel E. James, “Nine Safe Practices for the Microbiology Laboratory”, located on the Carolina® Science and Math Support Website obtained 7/25/2014)

http://www.carolina.com/teacher-resources/Interactive/nine-safe-practices-for-the-microbiology-lab/tr11085.tr

 

"It Came From Africa"-A Case Study

As our semester comes to a close, we have been covering parasites of all shapes, sizes, and types.  I have really enjoyed reading the case studies on the CDC website, like the one I shared last week, and thought that I would continue by sharing another which involves someone who contracted a parasite during a trip to Africa.

As with any case study, the narrative and patient history are the most important parts, so that is where this begins.

Case #362 - December, 2013

“A 29-year-old female post-graduate student in Zoology went on an expedition to see the lowland gorillas in the Democratic Republic of Congo. She reported numerous insect bites while traveling but did take anti-malarial prophylaxis. Approximately one week after returning home she developed fever. About a month later, she started experiencing headaches, itchy skin, and swollen lymph nodes and sought medical attention. A blood specimen was collected; smears made and stained with Wright-Giemsa.”¹

 

 

 

"Case #362 – December, 2013." DPDx - Laboratory Identification of Parasitic Diseases of Public Health Concern (Figure D)

 

Based off the findings of the peripheral blood smear and the organisms which were observed as well as the case history, the diagnosis was Trypanosoma brucei; most probably the Trypanosoma brucei gambiense subspecies due to the geographic location of where the individual traveled.¹

These organisms are transferred to humans by the bite of the Tsetse fly, which allows an immature stage of the organism’s life cycle to be introduced to the human host.  Symptoms can range from headaches, like the individual in the case study, to coma/death once more central nervous system involvement occurs.

Treatment of this disease depends on what disease stage that the organism has been able to progress; such as whether it has crossed the blood brain barrier or is just in the blood stream.²  The drugs used to treat this type of infection are typically only available from the Centers for Disease Control.²  After treatment, an infected individual will need to have repetitive examinations of their cerebral spinal fluid in order to rule out a relapse of the disease.²

 

Works Cited

1.       "Case #362 – December, 2013." DPDx - Laboratory Identification of Parasitic Diseases of Public Health Concern. CDC, November 29, 2013. Web. 18 July 2014.

http://www.cdc.gov/dpdx/monthlyCaseStudies/2013/case362.html

 

2.       "Parasites - African Trypanosomiasis (also known as Sleeping Sickness)." Centers for Disease Control and Prevention. CDC, August 29, 2013. Web. 18 July 2014.

http://www.cdc.gov/parasites/sleepingsickness/treatment.html

 

 

Parasites, Laboratory Practices…. and a Case Study!

 Over the past week or so we have been covering material on protozoan parasites which included the standard procedures used in diagnosis as well as some specialized techniques.  As stated in my post from last week, these life forms can present difficulty in the processing, detecting, and diagnosis of disease compared to other organisms such as bacteria.

The standard techniques for the detection of intestinal parasites include a direct wet prep, a concentrated method, and a permanent stain.  The wet prep allows a technologist to look for motility of living, mobile forms of protozoan parasites known as trophozoites, while the concentrated prep increases the likelihood of observing a parasite, thus increasing the overall sensitivity. The permanent stain, usually a trichrome stain, aids in the ability of viewing cysts, eggs, etc by adding color to morphology which would normally not be easily observed. 

Some organisms may need special staining in order to be detected.  These include Cryptosporidium, Cyclospora, and Isospora which require an Acid-Fast staining technique to be utilized for their oocysts to be observed.

Here is a case study I came across on the CDC website which gives an example of laboratory methods in the detection of protozoan parasites.

“A 34-year-old missionary worker sought medical attention for abdominal pain, nausea, and watery diarrhea after returning from visiting friends in Central America. A stool specimen was collected for laboratory testing and a modified Kinyoun’s acid-fast stained smear was prepared.  The objects of interest measured 8-9 micrometers in diameter on average.”¹

 



Centers for Disease Control and Prevention-

DPDx Case #374-June,2014 (Figure A)¹

 

Based off the information provided in the case study along with the picture, it can be concluded that the causative pathogen was Cyclospora cayetanensis.  One of the clues which could aid in determining this is the fact that an acid-fast technique had to be used to view the oocyst.  Also, from our lectures I have learned that this organism causes traveler’s diarrhea and is endemic to Central America.

Here is the link to the case study I referenced in this post if you would like to see additional pictures.  There are also many other informative case studies available on their website which you might enjoy. 

http://www.cdc.gov/dpdx/monthlyCaseStudies/2014/case374.html

Works Cited

1. "Case #374 - June, 2014." DPDx - Laboratory Identification of Parasitic Diseases of Public Health Concern. CDC, June 2014. Web. 10 July 2014.

Cryptosporidium and Giardia Source Water Monitoring

This week in lecture we began covering material on protozoan parasites, which can cause a variety of diseases and can be harder to detect in the laboratory than other organisms such as bacteria.  In an attempt to take a slightly different angle on the subject, I thought that going over how some species can be monitored/detected in the environment would be beneficial. 

For the past seven years prior to entering the program, I worked as a biologist for an environmental testing laboratory, which participated in the EPA source water monitoring study of systems for Giardia and Cryptosporidium. During my time there I analyzed over 3,000 samples, so you could say that I somewhat familiar with the process.

The method is long, labor intensive, time consuming and could take up to a week to complete.  In general, a large sample of water is concentrated to just a few drops on a slide which is then stained and examined microscopically.

First, a roughly 10 liter sample of source water (which is the lake, river, etc that a water processing plant pulls from to make drinking water) is collected and filtered through a specialized filter that has pores small enough to catch the desired organisms.  Next, a soapy solution is added to the filter, which is then shaken to remove and resuspend any collected material.  This solution is then centrifuged to concentrate the dirt and any organisms into a pack pellet.  Then the supernatant is removed, the pellet is resuspended, and transferred to a small tube.  Next, a solution containing small iron beads coated in anti-Crypto and anti-Giardia antibodies as well as pH buffers are added to the tube with the sample.  The beads will grab onto the organisms, and in the presence of a magnet, allow the potential organisms to be separated from the remainder of the contents of the sample.   This process can then be reversed by the addition of acid, which elutes the organisms from the beads into the eluate and onto a microscope slide.  This can then be stained with fluorescent dyes and examined for the presence and enumeration of the cysts and oocysts which may be present.

For the EPA study, water systems were required to send these samples in once a month for two years.  After the required monitoring was completed, the data could be compiled to calculate the number of cysts/oocysts per liter which could be correlated to a risk for these organisms to contaminate the drinking water produced by the individual water system. 

Hopefully this was not too boring, but I thought that it would be useful for others to know how these organisms are detected from environmental samples in addition to their detection in human samples.