LAIs, or laboratory-acquired infections, are classified as an infection acquired through lab or lab-related activities, regardless of whether the infection symptomatic or asymptomatic. These infections can occur in clinical labs as well any other type of lab environment that may come into contact with a pathogenic substance. Some of the most common microbes responsible for these LAIs include Hepatitis B, C, and D, Salmonella thyphi, mycobacterium tuberculosis, and Brucella spp..
The most common modes of transmission for these diseases are inhalation, percutaneous inoculation, general skin contact and, finally, ingestion. Inhalation involves the use of aerosols and may occur when proper safety attire does not meet recommended standards. Percutaneous inoculation includes skin puncture with needles, cuts from items contaminated with pathogens, animal bites, etc. Contact related infections can occur when a pathogen comes into contact with mucous membranes such as eyes or mouth via hand or other general surface contact. Finally, ingestion related infections include breathing in fumes or accidentally eating or drinking a substance.
What are the risks?
In 1978, a study conducted by Pike and Sulkin identified 4,079 LAIs between 1930 and 1978. These included 168 deaths. More recently, a study by Harding and Byers found that 1,267 LAIs had occurred between the years 1979 and 1999, 22 of which resulted in death. Although the total number of LAI occurrences are beginning to decrease, it is likely the number of LAI’s is severely under-reported. This is due to the difficulty in determining if the infection was acquired while in a lab environment, or in a public or private space.
Further, even though the number is decreasing, the occurrences can still have dramatic consequences. For instance, at Texas A&M University, an accident occurred in 2006 which exposed lab workers to category B bioterror agents Brucella and Coxiella burnetti. These accidents pose a cross contamination threat outside of the lab if the workers were to expose themselves to friends, family, and others they come into contact with.
How to prevent LAIs
First, it is very important to follow CDC biosafety guidelines regarding biosafety in microbiological and biomedical laboratories. This will ensure safe handling of any dangerous pathogenic samples in the lab. Further, these guidelines establish proper equipment handling and personal safety equipment and protective attire as well.
It is very important to practice consistent and thorough decontamination practices. Of the various modes of transmission of pathogens within and throughout a laboratory environment, general surface contact may be the most common form of LAI and regular surface disinfection can greatly mitigate risk of infection. For thorough disinfection, it is recommended that laboratories use an intermediate-level, EPA approved hospital grade disinfectant.