ISO 14644 Part 1 update

Introduction

As part of the ISO periodic review cycle, ISO 14644-1, Cleanrooms and associated controlled environments — Part 1: Classification of air cleanliness is being revised. ISO TC209 Working Group 01, an international team of subject matter experts, is planning to assess the existing ISO 14644 document and propose changes for enhancements.

After discussing with statisticians, the expert working group is recommending modifications to the classification method. It is also implementing the key elements of ISO 14644-3, Cleanrooms and associated controlled environments — Part 3: Test methods in an effort to improve the document and thus enhance credibility and resulting quality.

Changes in Classification Method

The present ISO 14644-1 document depends on an ad-hoc approach to ascertain the location and number of sampling areas for classifying cleanrooms. This method, however, is not built on statistical sampling technique and also does not consider any risk-based evaluation. At present, the working group is recommending a randomized sampling location selection technique, in tandem with a risk-assessed, fixed-location sampling technique.

Founded on the hypergeometric statistical model, the randomized sampling technique enhances confidence that the selected sample provides 95% assurance that the results represent 90% of all areas in the cleanroom. Examining the additional risk, the fixed sampling location technique enables cleanroom users to choose the areas where their product is believed to be most at risk. When the cleanroom is classified first, these locations will be sampled, and whenever the room is re-qualified the locations will be sampled again.
When combined together, these two methods provide improved confidence that the cleanroom is operating as expected and ideal for providing the right quality-controlled environment for life science applications. These methods are better than the method specified in the existing ISO 14644-1 document.

Improving Confidence in Quality

In addition to cleanroom monitoring and classification applications in the life sciences and pharmaceutical industries, there are certain particle counters that can be utilized in indoor air quality  and other less critical industrial applications.

Figure 1. Particle counters can be designed for different applications

Although a number of air particle counters available in the market are designed for use in all three application areas, some give incorrect results in low particle concentration environments such as life-critical cleanroom applications, while others are unable to handle high particle population environments found in the industrial applications. Therefore, particle counters developed for the less critical industrial applications may not meet the rigorous requirements specified in ISO 21501-4 and ISO 14644-3.

In an effort to enhance confidence in the quality of cleanroom environments, the amended ISO 14644-1 document will comprise the performance criteria of particle counter specified in ISO 14644-3 and give a normative reference to ISO 21501-4, Determination of particle size distribution — Single particle light interaction methods — Part 4: Light scattering airborne particle counter for clean spaces, to guide the reader through a consistent test method for the calibration of particle counters. The ISO 21501-4 document was initially published in 2007.

Additionally, manufacturers of particle counters and national standards agencies have publicized the normative reference to ISO 21501-4 in the amended document ever since the initial draft of the revised ISO 14644-1 document was published in December 2010. Therefore, the working group believed that, by the estimated publication date of the amended ISO 14644-1 in 2013, the industries using the ISO 14644-1 document would have sufficient notification of the need to conform to the ISO 21501-4 calibration method and to also upgrade any particle counters that are non-compliant.

Prior to the publication of ISO 21501-4 in 2007, no calibration standards were available for airborne particle counters which resulted in fluctuating levels of performance from particle counting systems. Since 2007, many particle counter manufacturers across the globe have modified the designs of their particle counters meant for critical life science ISO 14644 applications, so that these instruments can fulfill the more complex expectations of the latest calibration standard. Now, cleanroom users can have improved confidence that their cleanrooms are providing the required level of quality-controlled environment for their specific processes.

Content Imported from ISO 14644-3

The performance requirements of particle counter have been laid down in the ISO 14644-3 document since its first publication in 2005 and corresponds with the ISO 21501-4.

Figure 2. Specifications for the light-scattering discrete-particle counter from ISO 14644-3

In an effort to enhance clarity, the International Standards Organization Technical Committee ISO TC 209 determined that particle counter performance methods and criteria used to attain classification should be integrated into each ISO 14644 standard. Therefore, the performance criteria of particle counter specified in Table C.1 of ISO 14644-3 will appear in the amended ISO 14644-1 document.

Publication timeline

The initial publication of the Draft International Standard (DIS) DIS ISO 14644-1 in December 2010 triggered a heated debate. After assessing the questions and comments from the international community with regard to the DIS, the expert working group planned to publish an amended draft DIS document in 2013. In the interim, ISO Technical Committee TC209 recommends that users who want to leverage the improvements in the 2010 DIS ISO 14644-1 document can use it, as long as they know that the final published version will be modified.

Conclusion

The improved sampling method in the revised ISO 14644-1 document along with the enhanced guidance for particle counter calibration and performance will provide improved confidence to cleanroom users that their cleanroom is delivering the preferred level of quality-controlled environment for critical life science applications.

Posted by Tim Sandle

Pharmacopeial Forum Vol. 40 No.5: Sep– Oct 2014

A new edition of the Pharmacopeia Forum has been issued. Among the items of interest are:

Chapter 1041 -           Biologics (Revision proposal target, USP38-NF33 2nd Supplement)

USP propose revision of this General Chapter to update definitions, references and to explain compendial requirements and perspectives pertaining to this class of products and future monographs. Chapter <1041> is cross-referenced in the following general chapters and monographs.

General Notices, 5.50.10 Units of Potency (Biological). These citations will remain as written when the revised chapter text becomes official.

Chapter 1207 -           Sterile Product Packaging – Integrity Evaluation (Revision proposal target, USP38-NF33 2nd Supplement)

Chapter 1207 has been extensively revised and subdivided into four related chapters.

1207.1 - Package Integrity and Test Method Selection [NEW]

(Revision proposal target, USP38-NF33 2nd Supplement)

This proposed new general chapter describes a range of package integrity test methods that are used for ensuring sterile package integrity. Different types of package defects that cause leaks are described, and information about their detection is provided. Limit of detection is discussed in detail for the different leak test methods.

1207.2 - Package Integrity Leak Test Technologies [NEW]

(Revision proposal target, USP38-NF33 2nd Supplement)

This proposed new general information chapter provides information guiding the selection and proper use of leak test technologies. These leak test methods are divided into two major categories: deterministic and probabilistic. For each leak test technology, the chapter provides a description and discusses applications, test equipment, and test parameters.

1207.3 - Package Seal Quality Test Methods [NEW]

(Revision proposal target, USP38-NF33 2nd Supplement)

This proposed new general information chapter summarizes test methods useful for characterizing and monitoring package seal quality. These methods are not leak tests but provide additional data regarding package seal characteristics that may affect package integrity and leakage. The purpose of this chapter is to provide information to guide the selection and use of package seal quality test technologies.

1210 - Statistical Tools for Procedure Validation [NEW]

(Revision proposal target, USP38-NF33 2nd Supplement)

A new general information chapter is proposed as a companion chapter to Validation of Compendial Procedures, <1225> with the purpose of providing statistical methods that can be used in the validation of analytical procedures.

Posted by Tim Sandle

Bacterial endotoxins Ph. Eur. policy for substances for pharmaceutical use

The European Commission has made an important announcement about endotoxin limits in relation to substances for pharmaceutical use. For new substances, pharmacopeia monographs will no longer specify endotoxin limits. It will be left to the user to determine if a substance requires testing and what the appropriate limit should be.

The issued text reads:

Bacterial endotoxins Ph. Eur. policy for substances for pharmaceutical use (Approved by the Ph. Eur. Commission at its 149th Session, June 2014)

1.Reasons for requirements for testing for bacterial endotoxins

Bacterial endotoxins are contaminants from gram-negative bacteria and are the most common cause of pyrogenicity in pharmaceutical products. Any preparation administered parenterally should be sterile and comply with the test for bacterial endotoxins (BET) as described in the Ph. Eur.

Substances to be used in parenteral preparations must comply with the BET, whatever their origin, since:

• Contamination by bacterial endotoxins can take place prior to or during the manufacturing process;
• Bacterial endotoxins cannot easily be removed by the manufacturing process;
• Bacterial endotoxins should be detected as early as possible in the manufacturing process.
• It is to be noted that the ICH Guideline Q6B: Specifications: Test Procedures and Acceptance Criteria for Biotechnological/Biological Products provides the following recommendation under section 4.1 Drug Substance Specification: “Pharmacopoeial tests (e.g., endotoxin detection) should be performed on the drug substance, where appropriate.”

2. Requirements for bacterial endotoxins in the Ph. Eur.

The Ph. Eur. provides requirements for testing for bacterial endotoxins as follows.

The general monograph Substances for pharmaceutical use (2034) and individual monographs on substances for pharmaceutical use require compliance with the BET when substances are used in the manufacture of parenteral preparations. The monographs refer to general chapters 2.6.14. Bacterial endotoxins and 5.1.10. Guidelines for using the test for bacterial endotoxins.

According to the general monograph Parenteral preparations (0520), pharmaceutical preparations to be used parenterally have to comply with the test for bacterial endotoxins or, where justified and authorised, the test for pyrogens.

3. Problem statement

During the elaboration of a monograph, it is not always known at the level of the manufacturing of the substance whether the substance is to be used for the production of a parenteral preparation and therefore it is not known whether compliance with the BET is needed or not.

With regard to the limits to be applied for the test, individual monographs provide limits whereas general chapter 5.1.10 provides a way to calculate the endotoxin limit:

Values of K to be used for the calculation of the endotoxin depend on the route of administration and are given in the general chapter (Table 5.1.10.-1). There are other ways to establish limits, for example based on process capability, patient population or specific requirements of the competent authority. These are not clearly stated in the Ph. Eur. This might result in apparent contradictions between the different BET requirements.

4. New policy on the way to prescribe the BET in the Ph. Eur.

With consideration to the above, the Ph. Eur. Commission recommends the following approach to bacterial endotoxins.

Elaboration of new individual monographs

A test for bacterial endotoxins is not included in new monographs for substances for pharmaceutical use. The requirements of the general monograph Substances for pharmaceutical use (2034) apply.

• A test is included only where a specific method has to be described, for example if a specific sample preparation has to be used or if a specific method has to be applied.
• If a test is included in the monograph, no limit is given for the test.

Existing monographs

BET specifications are kept in individual monographs for substances for pharmaceutical use. Existing limits remain in individual monographs to maintain the use of well-established limits.

In order for the policy to be applied, the following changes are proposed to existing Ph. Eur. texts.

• General chapter 5.1.10 is expanded with further considerations regarding the setting up of limits.
• General monograph Substances for pharmaceutical use (2034) is slightly reworded in order to take the above policy into consideration.

5. Consequences of the new BET policy for Ph. Eur. users

It is up to the user of the Ph. Eur. to determine whether compliance to BET is needed or not for a given substance. Where a test is included in the monograph with no specific limit, it is up to the user to set the limit for the substance, based on the following considerations: use of the substance (route of administration, patient population); calculation according to the formula given in general chapter 5.1.10; process capability; or any other considerations raised by the competent authority.

Source: Ph. Eur.

Posted by Tim Sandle

Microbiology of serious human disease

Scientists at the University's Centre for Biomolecular Sciences have shed new light on how two proteins found on many human cells are targeted by the human pathogen Neisseria meningitidis which can cause life-threatening meningitis and septicaemia.

The proteins, laminin receptor (LAMR1) and galectin-3 (Gal-3) are found in and on the surface of many human cells. Previous research has shown they play diverse roles in a variety of infectious and non-infectious diseases. For example, the LAMR1 is a key receptor targeted by disease-causing pathogens and their toxins and is also a receptor for the spread of cancer around the body and for the development of Alzheimer's.

Using the latest bimolecular fluorescence and confocal imaging techniques, the researchers have shown that these two separate proteins can form pairs made up of two similar molecules (homodimers) or one of each molecule (heterodimers) which are targeted by Neisseria meningitidis. They have also identified critical components which cause the formation of these pairs of molecules.

These new mechanistic insights into the three-way relationship between proteins and bacterial pathogens could have significant implications in the fields of infection, vaccination and cancer biology.

For further details see:

F. Alqahtani, J. Mahdavi, L. M. Wheldon, M. Vassey, N. Pirinccioglu, P.-J. Royer, S. M. Qarani, S. Morroll, J. Stoof, N. D. Holliday, S. Y. Teo, N. J. Oldfield, K. G. Wooldridge, D. A. A. Ala'Aldeen. Deciphering the complex three-way interaction between the non-integrin laminin receptor, galectin-3 and Neisseria meningitidis. Open Biology, 2014; 4 (10): 140053 DOI: 10.1098/rsob.140053

Posted by Tim Sandle

New book: Cleanroom Microbiology

A new book is being published by DHI/PDA – “Cleanroom Microbiology”. The book has been written by Tim Sandle and R. Vijayakumar.

While there are books on cleanrooms available, these focus almost entirely on the physical and rarely address microbiological risks. Similarly, there are various books on microbiology (even a few about pharmaceutical microbiology), yet these books rarely mention cleanrooms, or, where they do, give controlled environments limited coverage.

A new book is being published by DHI/PDA – “Cleanroom Microbiology”. The book has been written by Tim Sandle and R. Vijayakumar.

While there are books on cleanrooms available, these focus almost entirely on the physical and rarely address microbiological risks. Similarly, there are various books on microbiology (even a few about pharmaceutical microbiology), yet these books rarely mention cleanrooms, or, where they do, give controlled environments limited coverage.

To the authors of Cleanroom Microbiology, these two domains, normally separated by different functions, are inseparable. This book is about cleanrooms and controlled environments in relation to the pharmaceutical and healthcare sectors and is applicable to both the sterile and non-sterile pharmaceutical sectors with its focus on cleanroom microbiology.

The contents are:

1. Introduction to Cleanroom Microbiology

2. Cleanrooms, Clean Zones and Cleanroom Technology

3. Global Standards for Cleanrooms and cGMPs

4. Microbiological Environmental Monitoring of Cleanrooms: Part 1: Contamination Sources and Methods

5. Microbiological Environmental Monitoring of Cleanrooms: Part 2: Constructing an Environmental Monitoring Program

6. Cleanroom Microflora

7. Characterization and Identification of Cleanroom Microflora

8. Evaluation and Interpretation of Environmental Monitoring Data

9. The Human Microbiome Project and the Implications for Cleanroom Microbiology

10. Implications of Pharmaceutical Microbial Contamination

11. Contamination Control in Cleanrooms: Part 1: Disinfection Practices in Pharmaceutical Cleanrooms

12. Contamination Control in Cleanrooms: Part 2: Cleanroom Design Factors

13. Contamination Control in Cleanrooms: Part 3: The Personnel Factor

14. Contamination Control in Cleanrooms: Part 4: Media Simulation Trials

15. Auditing Cleanrooms for the Contamination Control Perspective

16. Cleanrooms and Microbiology: The Importance of Risk Assessment

The book is currently available for a special pre-order price.

For further details and to order, see PDA / DHI publications

Posted by Tim Sandle

WHO: Revision of its Process Validation Guideline

The World Health Organisation has published a second draft on the “Revision of its Process Validation Guideline”.

According to ECA, the table of contents and the scope have remained unchanged. Yet, the definition of process validation contains the life-cycle approach in the glossary already. Compared to the first draft, the new version now also explains the matrix approach or bracketing.

The main change is with the chapter "process qualification". Here it is stated that a risk assessment is required for the change in batch size from scale up to commercial batch size. Explicitly, manufacturers are requested to implement the new validation approach. However, it is mentioned that full implementation may take time. In the interim, the traditional approach or concurrent validation may be accepted. Also a hybrid approach (based on a scientific basis and risk management principles) may be an alternative.

For details see ECA

Posted by Tim Sandle

ICH Q12: Technical and Regulatory Considerations for Pharmaceutical Product Lifecycle

ICH has just published a Final Concept Paper for a new ICHQ12 guideline: Technical and Regulatory Considerations for Pharmaceutical Product Lifecycle.

According the ECA, the reason for the document is: “Currently, there is a lack of a harmonised approach to technical and regulatory considerations for the lifecycle management of pharmaceutical products. Although there are concepts in ICH Q8, Q9, Q10 and Q11 for a more science and risk-based approach for assessing changes across the lifecycle, several gaps exist which hinder a full realization of the benefits intended. The original aim of 'operational flexibility' in post-approval changes has not been achieved yet. The main focus at ICH to date is on early stages of the product lifecycle, especially on development and launch.”

For further details, please see ECA

Posted by Tim Sandle

FDA – general safety testing

Revocation of general safety test regulations that are duplicative of requirements in biological license applications.

Here,  FDA is proposing to amend the biologics regulations by removing the general safety test (GST) requirements for biological products. FDA is proposing this action because the existing codified GST regulations are duplicative of requirements that are also specified in biologics licenses, or are no longer necessary or appropriate to help ensure the safety, purity, and potency of licensed biological products. FDA is taking this action as part of its retrospective review of its regulations to promote improvement and innovation.

See: FDA

Posted by Tim Sandle

Excessive packaging woes

Packaging is a must for products. If your items are to hit the shelves in one piece and appeal to your target consumer base, they must be neatly contained in appropriate materials. However, packaging can be - and very often has been - taken too far. Partly, this has been down to the proliferation of packaging options. Firms are now spoiled for choice when they’re looking for materials to contain their products. This trend has also been fuelled by the consumer desire for increased convenience. There is high demand for pocket-sized products that are easy to open and consume or use.

If your firm has fallen into the trap of using excessive packaging, now’s the time to take action. After all, this could be hitting your finances. As well as shelling out for more materials, your transport costs could rise because of the extra bulk. Also, people are becoming increasingly aware of the environmental impact of packaging and they are looking for firms to take a responsible approach. The good news is, there are ways to cut packaging without sacrificing the overall look and feel of products. All too often, companies use two layers of packaging when one would be enough. For example, for some products, rather than putting already-wrapped products in external packages, such as boxes, it can suffice to use labels on internal packaging instead. High quality labels, such as packaging labels, bottle labels and food labels, can be sourced from expert companies such as Labels Plus.

The following examples should provide you with some ideas when it comes to resolving your excessive packaging woes.

Wal-Mart

One retailer that understands the importance of downsizing packaging is Wal-Mart. The multinational corporation set a goal in 2007 to reduce its use of packaging by five per cent by 2013. It reached this target one year ahead of schedule. According to the company, it achieved this success by adopting a “more holistic approach that considers the environmental and economic impact of packaging” throughout the supply chain.

As part of its efforts to streamline this side of its business, the firm managed to make its sauce bottles 44 per cent lighter. It also cut its use of corrugated cardboard in the transportation of processed meats by 26 per cent.

Staples

Also achieving impressive results, office supply specialist Staples significantly cut back its packaging use thanks to investments in state-of-the-art technology. The company installed ‘on-demand packaging’ equipment at a number of its fulfilment centres in the US. The devices automatically create custom-sized boxes for every case of goods deemed ‘less than full size’.

This has enabled Staples to reduce its use of corrugated cardboard by over 15 per cent. Meanwhile, the business has lowered its use of cut air pillows by around 60 per cent. In turn, this has helped the firm to fit more orders into each of its delivery trucks.

Dell

Another large corporation that has taken packaging seriously over recent years is Dell. The computer manufacturer now ships nearly seven in ten of its laptops inside bamboo packaging. Because it can grow very quickly, this wood is considered much more sustainable than many other packaging materials. It can also be sourced close to the company’s factories in China.

In addition, Dell has developed a biodegradable, organic material that it says performs better in drop tests than traditional Styrofoam. The innovative packaging product is made by combining common agricultural waste products with mushroom spawn.

Partly as a result of these savvy solutions, the business has managed to lower the size of its packaging by over 12 per cent. Also, it has increased the amount of recycled and renewable materials it uses by 40 per cent.

Whether you’re looking to revolutionise your firm’s approach to packaging or you simply want to make some tweaks to help you achieve greater efficiencies, these case studies should provide you with plenty of inspiration.

FDA new blood - syphilis guidance

The FDA has issued a new document:

“Guidance for Industry: Recommendations for Screening, Testing, and Management of Blood Donors and Blood and Blood Components Based on Screening Tests for Syphilis”

The guidance is intended for blood establishments that collect Whole Blood or blood components, including Source Plasma. The guidance announced in this notice finalizes the draft guidance of the same title, dated March 2013 (2013 draft guidance), and supersedes the memorandum of December 12, 1991, entitled “Clarification of FDA Recommendations for Donor Deferral and Product Distribution Based on the Results of Syphilis Testing.”

For details see: FDA

Posted by Tim Sandle

EU GMP Chapter 5 Production

A new draft of EU GMP Chapter 5 “Production” has been issued by the European Medicines Agency.

Changes have been made to sections 17 to 21, including adding a new section, to improve the guidance on prevention of cross-contamination and to refer to toxicological assessment. Changes were also introduced in sections 27 to 30, including adding a new section, on the qualification of suppliers in order to reflect the legal obligation of manufacturing authorisation holders to ensure that active substances are produced in accordance with GMP. The changes include supply chain traceability. Sections 35 and 36 are inserted to clarify and harmonise expectations of manufacturers regarding the testing of starting materials while section 71 introduces guidance on notification of restrictions in supply.

For details see: EMA

Posted by Tim Sandle

EU GMP Chapter 3 Premises and Equipment

A new draft of EU GMP Chapter 3 “Premises and Equipment” has been issued by the European Medicines Agency.

The main change from the previous draft is to section 6 as part of the improved guidance on prevention of cross-contamination which states:

 “3.6 Cross-contamination should be prevented for all products by appropriate design and operation of manufacturing facilities. The measures to prevent cross-contamination should be commensurate with the risks. Quality Risk Management principles should be used to assess and control the risks. Depending of the level of risk, it may be necessary to dedicate premises and equipment for manufacturing and/or packaging operations to control the risk presented by some medicinal products. Dedicated facilities are required for manufacturing when a medicinal product presents a risk because: the risk cannot be adequately controlled by operational and/ or technical measures, scientific data from the toxicological evaluation does not support a controllable risk (e.g. allergenic potential from highly sensitising materials such as beta lactams) or relevant residue limits, derived from the toxicological evaluation, cannot be satisfactorily determined by a validated analytical method.”

For details see: EMA

Posted by Tim Sandle

Good Documentation Practices

Good documentation practice is part of Good Manufacturing Practice (GMP) and therefore plays an important part in the manufacture of pharmaceuticals and medical devices[i]. To comply with GMP, facilities require documented systems based on specifications, manufacturing and packaging instructions, procedures and records. GMP demands that a Quality Assurance System is established within which documentation is essential. In particular, specific batch manufacturing documentation must be in place and the documents must make it possible to trace the history of each batch. This traceability needs to be possible for a minimum defined period (typically for at least one year after expiry of the batch).

In relation to this subject, Tim Sandle has written an article on Good Documentation Practice for the Journal of Validation Technology.

To view the article, go to: JVT.

The reference is:

Sandle, T. (2014) Good Documentation Practice, Journal of Validation Technology, Vol. 20, Issue 3, pp1-11

Posted by Tim Sandle

Microbial Detection for Pharmaceutical Water Monitoring

Azbil BioVigilant (www.biovigilant.com), inventors of Instantaneous Microbial Detection™, today announced the introduction of its new IMD-W™ rapid  microbial detection system for real-time water monitoring of pharmaceutical water sources.

“The IMD-W system is one of the first of its kind to respond to a call from the pharmaceutical  industry for on-line water bioburden analysis (OWBA),” said Jeffrey Weber, PAT project manager  at Pfizer and one of the founding members of the OWBA workgroup. He added, “BioVigilant’s  IMD-W system is a new complementary tool at our disposal, for trending the state of control of  water systems in real time through continuous bioburden monitoring.”

The system targets applications where the instrument can be used immediately to manage and  mitigate risks, increase process understanding, save energy through better use of heat sanitization cycles, and drive labor efficiencies.

Using laser-induced fluorescence, the IMD-W system simultaneously measures particle size and  determines whether a particle is biologic or inert. This optical design does not require staining or  reagents, and incorporates three light scatter signals with advanced software algorithms to detect  biologic particles and discriminate non-biologic “interferent” materials which could otherwise be  counted as biologics by other systems. The system may be used on-line for continuous  monitoring, or at-line, for point-of-use samples and in laboratory settings. Other features include a touch panel for easy-to-use operation, a set of standard reports for data export and analysis,  and a flexible communications interface for networking and integration with common industrial control systems.

The IMD-W system augments BioVigilant’s current product offerings focused on rapid microbial monitoring for air in pharmaceutical manufacturing areas and other controlled environments

Posted by Tim Sandle

The Ocular Microbiome

About five years ago, Valery Shestopalov of the Bascom Palmer Eye Institute at the University of Miami was speaking with his microbiology colleagues about the bacteria found on healthy eyes. Conventional wisdom at that time held that healthy eyes don’t harbor much microbial life—tears and blinking tend to clear away foreign objects, including bacteria. But Shestopalov’s early tests revealed something different. “The tests ran positive. All exposed mucosal epithelium are populated densely,” he said. In 2009, Shestopalov began the Ocular Microbiome Project with funds from his institution. Eventually, he secured a grant from the National Eye Institute and began collaborating with Russell Van Gelder at the University of Washington, who had been developing PCR-based diagnostic tests to identify bacteria and fungi on the eye. The project now has a dozen collaborators at five universities.

The team found that about a dozen bacterial genera dominated the eye’s conjunctiva, a third of which could not be classified. On the corneal surface, the researchers found a slightly different community. Again, about a dozen genera dominated. And everywhere they’ve looked, the researchers have found more than just bacteria.

The researchers also found that during keratitis infections—infections of the cornea—only about half as many bacterial varieties were present, most prominently Pseudomonas strains. The changes typically occurred well before a diagnosis of an eye infection, suggesting the ocular microbiome could inform future diagnostic.

One factor that may be expected to impact the composition of ocular microbiota is the use of contact lenses. Contact lens wear is one of the biggest factors leading to corneal infection. Common bacterial infections that can cause irritation and redness affect an estimated 7 percent to 25 percent of contact lens–wearers, and much rarer keratitis infections can even cause blindness. Researchers believe contact lenses make it easier for pathogens to colonize the surface of the eye by giving the bacteria something to adhere to. Sequencing biofilms from used contact lenses, Shestopalov’s team found evidence of microbial communities that were different from the ocular microbiomes of people who don’t use contacts.

A version of this article appeared on www.the-scientist.com.
Posted by Tim Sandle