In the realms of hospital pharmacy operations, the significance of environmental monitoring cannot be overstressed. It is the fundament upon which microbiological quality assurance rests – a crucial element for the safe production of sterile and non-sterile pharmaceutical preparations. In a groundbreaking study published in the “Saudi Pharmaceutical Journal” in May 2019, researchers sought to catalog and understand the microbial life that inhabit these controlled spaces – or cleanrooms – within the University Clinical Centre Ljubljana Pharmacy.

The Study at a Glance

This profound study was executed with the aim of compiling a comprehensive microbiota catalogue specific to four different hospital pharmacy cleanrooms. The intriguing revelation from their results was that a predominant 78% of the isolated bacteria were Gram-positive. Moreover, the majority, over 70%, of these microorganisms were identified as normal human microbiota, while 10-15% were air-borne, prevalently spore-forming bacteria belonging to the Bacillus genus.

DOI and Access

The information referenced in this article originates from the study titled “The environmental monitoring in hospital pharmacy cleanroom and microbiota catalogue preparation,” with a Digital Object Identifier (DOI): 10.1016/j.jsps.2019.01.007.

Significance of Cleanroom Monitoring

Cleanrooms in hospital pharmacies are engineered to maintain exceedingly stringent environmental controls. This includes regulation of airborne particles, temperature, humidity, and indeed, microbial populations. As such, environmental monitoring is indispensable. It involves the recurrent collection of microbial samples to ensure the environment adheres to compliance standards – particularly critical for sterile pharmaceutical manufacturing.

This act of vigilance serves multiple functions. It provides assurance of the continuous protection of the pharmaceutical products from contamination, secures the health of the patients receiving these medications, and complies with regulatory requirements, including those outlined in the Eudralex’s Annex 1: “Manufacture of Sterile Medicinal Products” provided by the European Commission (European Commission, 2009).

Methodologies in Microbial Monitoring

Traditionally, microbial monitoring has relied on culture-dependent techniques involving growing colonies in nutrient cultures, thereby quantifying the colony-forming units (CFUs). However, the study by Tršan and colleagues implemented both culture-dependent methods and rapid microbiological methods (RMMs) using Adenosine triphosphate (ATP) bioluminescence, a rapid sanitation monitoring technique (Dixon, 2007). This allowed a comparison of the established and modern practices, potentially expediting microbiological monitoring.

Cleanroom Microbiota – A Closer Look

Understanding the cleanroom microbiota is paramount for several reasons. Primarily, it assists in differentiating between typical and abnormal microflora, which is crucial for distinguishing contamination and assessing risks. The research collaboratively conducted by Mateja Tršan, Katja Seme, and Stanko Srčič is foundational in this aspect.

In compiling the microbiota catalogue, it was observed that the presence of human-associated microorganisms suggests personnel as a primary contamination source, echoing the findings of prior studies (Whyte, 1996; Hussong et al., 2004). This ties closely to the standards and practices of personnel involved in the cleanroom operations – an indication of the necessity for stringent hygiene and operational protocols in these environments.

The discovery of Bacillus species aligns with earlier observations wherein air handling systems contribute to an influx of spore-forming bacilli, which can be resistant to desiccation and possess the ability to survive the cleanroom’s hostile conditions (Sandle, 2011; Kodaka et al., 1996).

The Importance of ATP Bioluminescence in Environmental Monitoring

ATP bioluminescence has been heralded as a revolutionary technique in the sphere of environmental monitoring and has been widely studied for its applications in cleanrooms (Dixon, 2007; Willis et al., 2007). Its significance lies in its ability to promptly detect live microorganisms by quantifying ATP – an indicator of viable biomass, thus offering a rapid response tool to assess cleanliness and microbial control, which could be particularly advantageous in time-sensitive pharmaceutical processes (Venkateswaran et al., 2003).

Implications and Applications of the Study

This innovative study has prime implications in the field of pharmaceutical sciences and microbial quality control. The findings could advocate for the establishment of new guidelines in environmental monitoring practices, encouraging an integration of RMMs alongside traditional methods, which is supported by several pharmaceutical microbiology experts (Duguid et al., 2011; Hussong & Mello, 2006).

Moreover, the creation of a detailed microbiota catalogue serves as an invaluable resource that could be employed for the training of personnel, development of custom cleaning protocols, and bolstering of hygiene controls, ultimately fortifying the fortresses that are cleanrooms against microbial invasion (Griffith et al., 2000).


1. Hospital Pharmacy Cleanroom Monitoring
2. Environmental Monitoring Cleanrooms
3. Cleanroom Microbiota Catalogue
4. Rapid Microbiological Methods (RMMs)
5. ATP Bioluminescence Environmental Monitoring


1. Saudi Pharmaceutical Journal (2019). The environmental monitoring in hospital pharmacy cleanroom and microbiota catalogue preparation. [DOI: 10.1016/j.jsps.2019.01.007] 2. Becker K., Heilmann C., Peters G. (2014). Coagulase-negative Staphylococci. Clin. Microbiol. Rev., 27(4), 870–926. [PMC4444509] 3. Dixon A.M. (2007). Environmental monitoring for cleanrooms and controlled environments. CRC Press.
4. Hussong D., Madsen R.E. (2004). Analysis of environmental microbiology data from cleanroom samples. Pharm. Technol., 28(5 SUPP), 10–15.
5. Sandle T. (2011). A review of cleanroom microflora: types, trends, and patterns. PDA J. Pharm. Sci. Technol., 65(4), 392–403.

Fostering keen awareness and deeper understanding of environmental monitoring in pharmacy cleanrooms is essential for enhancing patient safety and the integrity of pharmaceutical products. The pioneering cataloguing of cleanroom microbiota by Tršan et al. is a beacon guiding the advancement of pharmaceutical practices, and the fusion of traditional and RMMs forebodes a future that is both innovative and securely grounded in scientific rigor.