This book is aimed at Pharmaceutical microbiologists, with the idea of offering a different perspective on longstanding areas of testing (such a bioburden) as well as the new (rapid microbiological methods and risk assessment); at students of microbiology, pharmacy and healthcare subjects; and at personnel working in the field of pharmaceuticals, medical devices, biotechnology and healthcare, who wish to gain an understanding of the discipline or a specific area, such as disinfection or sterilization.

In terms of the structure of this book, Chapter 1 is an introduction to pharmaceutical microbiology, including a basic undertaking of microbial growth [2]. The chapter considers some of the key tests undertaken in pharmaceutical microbiology laboratories and outlines these along the path of pharmaceutical manufacturing (from starting materials to finished  products). The chapter also addresses testing in support of products, utilities and the assessment of cleanrooms. Some basic matters in terms of counting plates, sampling, speciation, and risk assessment (including the necessity of a contamination control strategy) are addressed. The chapter provides a stand-alone introduction to the subject matter.

Building on the first chapter, Chapter 2 presents an outline of the pharmaceutical industry with a focus on the role of the microbiologist within it. For those readers unfamiliar with the intimate working of the pharmaceutical industry, the  Chapter outlines the different aspects and the process of drug development. Pharmaceutical development and manufacture are regulated through good manufacturing practice (GMP). Chapter 3 looks at GMP and compliance and, at the same time, compares and contrasts the approach of international regulators such as the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA). Included in the chapter is the importance of key pharmacopeia, which provide the basis of many  laboratory tests. To be effective, the pharmaceutical microbiologist needs to understand the compliance arena.

Chapter 4 looks at an oft overlook aspect, and this is with the design, set-up and management of the microbiology laboratory. As well as good design principles, the chapter considers laboratory safety and associated microbiological risks and the qualification of equipment. The chapter, with a nod towards total quality management, introduces the topic of “lean labs” and the issue of harnessing laboratory resources efficiently.

Microbiological culture media is the foundation to many aspects of microbiology [3]. Even with the dawn of rapid microbiological methods, growing microorganisms is essential (and many rapid microbiological methods are, in fact, growth based). Chapter 5 discusses the different types of culture media, variations of the testing regimes designed to release culture media into the laboratory, and the important steps that need to be followed when manufacturing culture media.

Chapter 6 continues with the microbiology laboratory and reviews the principle methods that form part of the pharmaceutical microbiologist’s armory. Considered here is good laboratory practice, health and safety, aspect technique, microscopy, and culture-dependent methods. From this, the tests considered are total viable aerobic count, tests for specified microorganisms, optical density measurements, the test for sterility, pyrogen testing, endotoxin testing, and water analysis. With each test, aspects relating to method validation are highlighted, together with best practice advice.

The following chapters discuss the more important microbiological methods in more detail. 

Chapter 7 is concerned with bioburden testing. The chapter presents the main test methods for conducting bioburden, including plate counting (pour plates, spread plates, and membrane filtration) and the most probable number technique. Animportant discussion is contained within the chapter in relation to the “colony-forming unit” (what it is and what it is not) and the complexities of counting microorganisms in terms of under- and over-estimation. For readers interested in sterile products, a section is included on pre-final filtration bioburden determination. 

Chapter 8 is about objectionable and specified microorganisms. Although the specified microorganisms listed in the major pharmacopoeia cannot be overlooked, the emphasis in the chapter is upon risk and the importance of the microbiologist understanding the products and processes so that those microorganisms that could damage the product or cause harm to the patient are characterized and tracked. This additionally requires knowledge of the interaction between microorganisms and people, which is addressed through an introduction to the metagenomics of the Human Microbiome Project.

Understanding the types of microorganisms, as use as controls in testing, to confirm organisms used in product development or to identify contamination is a core part of pharmaceutical microbiology [4]. With contamination events and out-of-limits events, failure to characterize invariably leads to a failure to conduct an  nvestigation soundly. Chapter 9 is about microbial identification and the chapter presents an array of phenotypic and genotypic methods. Given that choice between competing methods can often be bewildering, the chapter offers a matrix that can be adopted for selection and qualification.

Water is an important concern for microbiologists and the use of water is an inescapable feature of pharmaceutical production. Water, when produced and controlled properly, plays an effective role. However, poor design and control can lead to severe microbiological issues, not least because water acts as both a growth source and a vector for microbes. Chapter 10 looks at supplied potable water and the purification process that generates purified water and water for injections. As well as good design principles, the chapter also discuss the types of microorganisms found and requirements of testing for viable counts, bacterial endotoxin and total organic carbon.

Closely related to water is bacterial endotoxin, which is the major source of pyrogens within the pharmaceutical organization. Chapter 11 looks at the nature and sources of endotoxin (and Gram-negative bacteria) and the nature and risks of pyrogenicity. In addition, there is an in-depth review of the primary test for endotoxin:Limulus amebocyte lysate (LAL) method. Chapter 12 places microbiology at the core of many production processes and examines sterility and sterility assurance. The microbiologist needs a core understanding of sterility assurance principles, whether this is for sterile products or medical devices, or for the consumables used within cleanrooms and laboratories [5]. The chapter examines the theory of sterilization and some of the different methods that can be deployed to achieve it. The theme of sterility is extended to Chapter 13, which considers biological indicators (preparations of microbial spores) used to qualify sterilization (such as moist heat, dry heat, ethylene oxide, and hydrogen peroxide). The chapter discusses concepts such as D-value, population and identification, with a focus on biological indicator resistance.

Chapter 14 examines antimicrobials. An antimicrobial is any substance of natural, semi-synthetic or synthetic origin that kills or inhibits the growth of microorganisms but causes little or no damage to the host. In undertaking this, the chapter considers two important aspects of pharmaceutical product efficacy. The first is the assessment of antibiotics to determine if the antibiotic is effective against the target microorganism. The second is the assessment of pharmaceutical products that contain preservatives, where testing is undertaken in order to assess whether the preservative can suppress the growth of any contaminating microorganisms.

Cleaning and disinfection are of great importance to process environments. Without efficient cleaning (removal of soil) then disinfectants will not work effectively, and without a robust disinfection programme, then microorganisms will be present, either numerically or in terms of problematic species, at levels that present an environmental challenge to the product [6]. Chapter 15 presents an overview of detergents and disinfectants, and discusses issues of qualification and best practice advice for the use of such agents within a GMP environment.

Pharmaceutical processing needs to take place within a controlled environment and, in most cases, there is the requirement for a classified cleanroom. Chapter 16 reviews the design requirements for cleanrooms (air handling systems and the role of air in removing contamination). The chapter also discusses clean air devices, such as isolators and safety cabinets. The chapter devotes space to environmental control and environmental monitoring, and describes the fundamentals for designing an environmental monitoring programme as part of a bio-contamination control strategy.

Many of the laboratory methods used in pharmaceutical microbiology have remained unchanged for decades (some, such as classic counting methods being largely unchanged since the nineteenth century). The twenty-first century has seen the advent of rapid microbiological methods. These methods are designed to provide a faster time-to-result and/or a more accurate assessment of microbial numbers. Chapter 17 assesses the different types and technologies of rapid methods available, and discusses how the microbiologist can be best placed to select from different  (and at times competing) technologies. The main contribution that the pharmaceutical microbiologist can make to ensuring the safety of medicines is through risk assessment. Chapter 18 presents an introduction to risk assessment and its alignment with current GMP. The chapter then considers some risk assessment tools and techniques before moving on to outline some of the main sources of contamination within the facility. The chapter then presents some examples of risk assessment tools based on surface and air contamination. These examples show that risks can be quantified, compared and contrasted.

Chapter 19 describes another important area where pharmaceutical microbiologists should be at the forefront: validation of pharmaceutical equipment. Most items of equipment are designed to be self-sanitizing or self-sterilizing, or, alternatively, this has to be carried out manually. The pharmaceutical microbiologist must be closely involved in this process. The chapter describes the essential of validation, running through installation, operation and performance qualification. The importance of contamination control is illustrated through the example of cleaning validation. In addition to validation, the microbiologist should understand the batch manufacturing process and its constituent steps. The chapter describes this process fully and pinpoints where microbiological input is required.

Microbiological testing is of little value if the data are not analyzed. Chapter 20 is about the analysis and interpretation of microbiological data. This task is not as straightforward as with other biological data because microbial data rarely conform to standardized normal distribution. The marketed skewness of microbial data either requires the data to be transformed or for alternatives methods to be used. The handling of data is discussed with a view to producing control charts. A second area that the microbiologist needs to undertake frequently is the setting of alerts and action levels.

The chapter presents ways to set such limits. An efficient microbiology laboratory must conform to accepted standards, whether this be to GMP or International Organization for Standards (ISO) or to a national accredited body. The best means to assess these standards is through regular audit. Chapter 21 is about auditing the microbiology laboratory. The chapter will be of interest to readers who need to undertake auditing and/or work in laboratories that are subject to audit. The chapter discusses the audit process and the main areas that the auditor should focus on. 

The final chapter of the book, Chapter 22, acts as a conclusion. In completing this task, the chapter thematically draws together the key points made throughout the text. The title of the chapter is “Microbial Challenges to the Pharmaceutical Industry.” The chapter looks at microbial risks to pharmaceuticals, including points where contamination can arise and how risk assessment is the most effective tool to avoid such contaminating events. The chapter also considers the microbial risks to process environments. In running through these sources, the chapter ties together the main issues of contamination concern.