Safety Precautions and Operating Procedures in an (A)BSL-4 Laboratory: 2. General Practices

Summary

Performing viral assays in a BSL-4 laboratory is more involved compared to work in a BSL-2 laboratory due to required additional safety precautions. Here, we present an overview of practices and procedures used inside a BSL-4 laboratory illustrating proper Class II biosafety cabinet usage, waste management/disposal, and sample removal.

Abstract

Work in a biosafety level 4 (BSL-4) containment laboratory requires time and great attention to detail. The same work that is done in a BSL-2 laboratory with non-high-consequence pathogens will take significantly longer in a BSL-4 setting. This increased time requirement is due to a multitude of factors that are aimed at protecting the researcher from laboratory-acquired infections, the work environment from potential contamination and the local community from possible release of high-consequence pathogens. Inside the laboratory, movement is restricted due to air hoses attached to the mandatory full-body safety suits. In addition, disinfection of every item that is removed from Class II biosafety cabinets (BSCs) is required. Laboratory specialists must be trained in the practices of the BSL-4 laboratory and must show high proficiency in the skills they are performing. The focus of this article is to outline proper procedures and techniques to ensure laboratory biosafety and experimental accuracy using a standard viral plaque assay as an example procedure. In particular, proper techniques to work safely in a BSL-4 environment when performing an experiment will be visually emphasized. These techniques include: setting up a Class II BSC for experiments, proper cleaning of the Class II BSC when finished working, waste management and safe disposal of waste generated inside a BSL-4 laboratory, and the removal of inactivated samples from inside a BSL-4 laboratory to the BSL-2 laboratory.

Introduction

As safety of laboratory personnel handling high-consequence pathogens (no infection prophylaxes nor treatment options exist) is paramount, the US Department of Health and Human Services has established guidelines for facility construction and best practices for the safe conduct of work with pathogens in biomedical and clinical laboratories from a biosafety perspective¹. Through legislation and regulation, many of the practices and procedures have become mandatory requirements that must be followed for work with these pathogens. In the US, pathogens that are easily transmitted from person to person, result in high case-fatality rates, and/or have the potenti....

Protocol

1. Laboratory Entry

1. Gather all supplies from a BSL-2 laboratory for the experiment (e.g., cells, media, and consumables) prior to entry into the BSL-4 laboratory.
2. Complete the BSL-4 entry procedure (outlined in detail in reference⁷).

2. Preparation of a Class II Biosafety Cabinet in the BSL-4 Laboratory

1. Once inside the BSL-4 laboratory, ensure the daily internal checklist (Figure 1) has been completed. Complete the checklist if the checklist has not been previously filled out and indicate which viruses will be used. If the checklist has already been completed, add....

Results

Following proper procedures within the BSL-4 laboratory are critical for ensuring safe and effective completion of assays. By referring to the completed daily internal checklist (Figure 1), laboratory staff ensure that equipment is fully operational. Proper body positioning in the center of the BSC ensures that the experiment is performed under optimum air flow conditions (Figure 2). The virus sample is serially diluted to obtain plates that have 30-300 p.......

Discussion

Work in a BSL-4 laboratory requires considerable time and additional attention to detail. Any type of work in this environment requires well trained, thorough, and conscientious individuals. The standard viral plaque assay provides an accurate model of a common procedure for working with high-consequence pathogens in the BSL-4 laboratory, as the assay involves several major concepts in which laboratory workers must be trained.

The first major concept is the proper use and application of safe p.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Micro-Chem Plus	National Chemical Laboratories	255
Ethanol	Fisher	BP2818500
2 ml 96-Deep Well Plates	Fisher	278743
10 ml Serological Pipette	Fisher	13-678-11E
25 ml Serological Pipette	Fisher	13-678-11
6-well plates	Fisher	140675
Crystal Violet	Sigma	HT90132-1L
10% Neutral Buffered Formalin	Fisher	22-050-105
Tragacanth	Fisher	50-702-2000
20 μl Pipette Tips	Fisher	21-402-550
200 μl Pipette Tips	Fisher	21-402-561
1,000 μl Pipette Tips	Fisher	21-402-581
DMEM	Lonza	12-604Q
FBS	Sigma	F2442-500mL
Penicillin/Streptomycin	Lonza	17-602E
2x EMEM	Quality Biological	115-073-101
Pipettor	Drummond	4-000-101
1,000 μl Pipette	Rainin	L-1000XLS+
200 μl Pipette	Rainin	L-200XLS+
12-Well, Multichannel 200 μl Pipettor	Rainin	L12-200XLS+
8-Well, Multichannel 1,000 μl Pipettor	Rainin	LA8-1200XLS
Attest	Express Medical Supplies	MMM12192
Autoclave	Getinge	GEB 2404 AMB-2
Autoclave Bag	Fisher	01-828E
2,000 ml Beaker	Fisher	02-591-10H
Autoclave Tray	Fisher	13-359-20B
Pipette Tray	Fisher	13-361-5
37 °C Incubator	Fisher	WU-39321-00
Biohazard Can	Rubbermaid Commercial	FG614500 RED
Autoclave Tape	Fisher	15-903
Autoclave Rod	Made by IRF Facility	N/A
Light Box	Fisher	S11552
Heat Sealer	Fisher	NC9793612
Heat Seal Pouches	Fisher	01-812-25H
Biohazard Bag	Fisher	01-828E