Microbial control is critical in cleanroom environments. Contaminated environments can lead to product recalls, regulatory observations, fines, or even consumer deaths. In order to properly prevent, destroy, and monitor microbial contamination in cleanrooms, several aspects of cleanroom microbiology must be understood. This four-part article provides a foundational introduction to some of those aspects. Parts 1 and 2 provided an introduction to cleanroom microbiology, discussion of guidance documents and FDA observations, and a summary of common sources of microbial contamination in cleanrooms. This part (Part 3) will discuss aspects of cleanroom gowning.
Recall that humans are the primary source of contamination in cleanrooms.2 They are critical to the microbial regulation of the cleanroom and thus must be properly gowned. The primary purpose of cleanroom gowning is to protect the product and the environment from microbial contamination.4 When used correctly, cleanroom gowning greatly reduces the microorganisms released by personnel.2
All personnel are required to be properly trained and gowned before entering the cleanroom. Proper training, education, hygiene, qualification, and authorization for entry are required.1 Many companies will use badge access to limit access to the cleanroom to authorized personnel only. Badge access makes it easier to lock out employees with expired training requirements.
Personnel must maintain good hygiene. This encompasses taking a daily shower to reduce skin shedding, frequently washing one’s hair, removing jewelry and makeup, proper handwashing prior to gowning, and keeping an open line of communication with management regarding sickness and compromised skin conditions. Sick employees or ones with compromised skin (such as fresh tattoos or sunburn) should not enter the cleanroom.1
There are many different gowning supplies available on the market, and materials may vary. Gowning components may be purchased either as sterile for one-time use or in reusable form. Reusable gowns must be managed to ensure the integrity of the garment is maintained through multiple washing and sterilization cycles. Both the washing and the sterilization processes must be validated.4 There are pharmaceutical laundry services available that can manage these activities.
In order for scrubs to provide a good inner suit for aseptic gowning, they should cover as much skin as possible. Scrubs and cleanroom gowning supplies (face masks, hoods, protective goggles, gloves, coveralls, and boots) should be sterile and made of non-particle-shedding material.1 When gowning, personnel should take care to use aseptic gowning practices. These include gowning from the top down, wearing sterile nonpowdered gloves, and not touching the outside of the sterile gown. After gowning, no skin or hair should be exposed.1
An aseptic gowning qualification program should be established to assess the ability of personnel to maintain the quality of the gown after gowning.3 The personnel gowning qualification should be performed by an analyst who enters the aseptic cleanroom to ensure that proper gowning techniques are followed. In addition, routine personnel monitoring should be performed by obtaining surface samples of each operator’s gloves on a daily basis or in association with each lot produced. Personnel should also be monitored after critical operations.1 As part of training, operators should understand not to sanitize their gloved hands just prior to being sampled for personnel monitoring because that can prevent recovery of microorganisms that were present during aseptic manipulations.
Periodic requalification is also essential. This provides additional microbial information and helps to ensure consistent acceptability of gowning techniques employed. Typically, a one-year requalification is sufficient if the monitoring data indicates the areas are in a state of microbial control.3
Personnel gowning qualification should consist four stages. Stage 1 is Initial Training and Education, which includes classroom training sessions. Training is mentioned in multiple guidance documents. The 2004 FDA Guidance for the Industry on Sterile Drug Products Produced by Aseptic Processing - Current Good Manufacturing Practice states “Appropriate training should be conducted before an individual is permitted to enter the aseptic manufacturing area. Fundamental training topics should include aseptic technique, cleanroom behavior, microbiology, hygiene, gowning, patient safety hazards posed by a nonsterile drug product, and the specific written procedures covering aseptic manufacturing area operations. After initial training, personnel should participate regularly in an ongoing training program.” 3
Annex 1 states that “All personnel (including those concerned with cleaning and maintenance) employed in such areas should receive regular training in disciplines relevant to the correct manufacture of sterile products. This training should include reference to hygiene and to the basic elements of microbiology.”1
Course topics for the Stage 1 Initial Training and Education phase can consist of Personal Hygiene, Basic Microbiology, Aseptic Techniques, Cleanroom Behavior, Patient Safety, Aseptic Clothing and Gowning, Concept of First Air, Contamination Control, Facility Design, Material and Personnel Flow, Cleaning, Disinfection/Sanitization, and Sterilization, Environmental Monitoring, Process Simulations, and Specific Company Procedures. These topics can be combined in a number of ways to develop a solid baseline education and initial training.
Stage 2 includes Gowning Training, Practice, and Observation. During this stage, the trainee is taught gowning techniques and glove sanitization in a safe noncritical area, such as a conference room. Proper techniques begin with good hygiene. In this training stage, the employee should have already removed any makeup and jewelry, placed on a hairnet (or bouffant), properly washed their hands, donned sterile scrubs with care, donned shoe covers, and be properly gowned to be in a Grade C area according to site procedures.
Once the employee is “ready” to gown for the Grade B area, a top-down gowning approach is typically used. Sometimes, a second hair cover is placed on the head. Gloved hands should be sanitized prior to beginning the gowning process. Depending on the company, the face mask can be placed on before or after the sterile hood. In this example, the face mask will be placed on after the sterile hood. All gowning component packaging should be examined for integrity and expiry dating prior to use.
Once the hood is deemed acceptable for use and gloved hands have been sanitized, the package is opened and the hood is manipulated by touching only the inside surfaces of the hood. The hood is gingerly placed over the head, taking care to not touch the outside surfaces. Hands should be sanitized again after donning the hood. The face mask should be donned at this point and formed to the face and nose contours. Then, the gloved hands should be sanitized again.
Next, carefully open the sterile coveralls, taking care to only touch the coveralls by handling the inside surfaces and not allowing the coveralls to touch the floor. Don the coveralls one leg at a time. Be careful to not drag the outside of the coveralls over the shoulders of the scrubs and ensure the hood is properly tucked into the neck of the coveralls. While crossing one’s legs to hold the garment in place, zip up the coveralls and snap any closures. Sanitize the gloved hands again.
Carefully open the booties taking care to touch the booties by handling only the inside surfaces. Don the booties one foot at a time by carefully slipping the booties over the footwear. Tighten and snap all of the closures on the booties to form the bootie to the foot. In a cleanroom gowning area, this would be performed one foot at a time while crossing a demarcation from the dirtier area to the cleaner area.
After sanitizing the gloved hands again, sterile goggles are carefully donned. The goggles should overlap the hood and face mask. All skin should be covered. The gloved hands should be sanitized again prior to donning a second pair of sterile powder-free gloves. Again, only the insides of the sterile gloves are touched to prevent contamination, and then the new sterile gloves are sanitized.
The trainee is allowed to practice these gowning steps in a safe, noncritical environment under the observation of a qualified trainer. When both the trainee and trainer feel comfortable with the trainee’s gowning technique, Stage 3 may begin.
Stage 3 is the qualification to enter Grade B areas. During Stage 3, general growth media contact plates are utilized to analyze whether the trainee gowned correctly without contaminating the sterile outer gown, sterile gloves, and sterile head cover. The employee is observed gowning, and then the gowning components are sampled in several areas with the contact plates to determine the level of microbial contamination on the gowns.3 The trainee must undergo three successive gowning processes and be evaluated through microbiological sampling. Guidance on where to sample personnel is vague, but multiple documents emphasize gloved fingers. The guidance documents stress that sampling sites should be justified.2 Sites that are often sampled include gloved fingers, forearms, chest, shoulders, thighs, hoods, and boots. Some companies include the face mask. If the face mask is monitored, the justification for analyzing the site should include recognition that the face mask is not a total barrier against microorganisms. Operators should be properly trained not to shout or talk excessively while gowning or while properly gowned in the cleanroom area. Note that passing stages 1 through 3 only qualifies an employee’s ability to gown into a Grade B area. Personnel should not assist with Grade A activities until they participate in a media fill.
Stage 4 consists of program maintenance, routine monitoring, requalification, and disqualifications, when warranted. Requalification may include participation in educational refresher courses, a single successful gowning qualification, and an annual participation in a successful media fill (as applicable).3
In order to protect the environment and the product, the integrity of the cleanroom gown must be maintained. This is partly accomplished through thorough training and education of the employees.
Cleanroom microbiology encompasses a variety of subjects, including cleanroom gowning. All personnel entering cleanrooms must be properly trained and gowned.1 Gowning helps control contamination from humans, but when not done correctly, or if the gowning has been compromised, the risk of contamination increases. It is essential to practice good aseptic technique, good hygiene, good gowning practices, good cleanroom behavior, and proper material transfer, as well as following all SOPs and not taking shortcuts.
The final article in this series will address concepts of environmental monitoring and the importance of disinfectant efficacy and proper cleaning.
About The Author:
Crystal M. Booth, M.M., is a senior technical director at Avista Pharma Solutions. She has over 18 years of experience in pharmaceutical microbiology, working in both R&D and quality control laboratories, including a startup company.
During her career, Crystal has developed and validated methods for antibiotics, otic products, topical creams, topical ointments, oral solid dose products, oral liquid dose products, veterinary products, human parenterals, vaccines, biologics, aseptically filled products, and terminally sterilized products. Those methods include microbial limits testing, bacterial endotoxins testing, particulate testing, sterility testing, pharmaceutical water system validations, environmental monitoring programs, surface recovery validations, disinfectant efficacy studies, minimum inhibitory concentration testing, antimicrobial effectiveness testing, hold time studies, and various equipment validations. She has experience working with global markets and regulatory bodies.
Crystal is a technical author and public speaker in the microbiology industry, and she also teaches aseptic gowning qualification classes. She earned her bachelor’s degree in biology from Old Dominion University and her masters in microbiology from North Carolina State University.