Pharmaceutical grade water is critical material for equipment cleaning, as well as ingredient water in drug products, so it deserves our attention. Commonly expressed misconceptions held by pharmaceu-tical professionals including microbiologists, who should know better, about water monitoring in-clude:
• Potable water does not contain coliform bacteria.
• Incoming potable water from a water authority must be monitored at least weekly.
• The USP chapters <61> and <62> contain suitable tests for monitoring water.
• Purified water should routinely be screened for the absence of the USP specified bacteria E. coli, P. aeruginosa, and S. aureus, and the objectionable bacterium B. cepacia.
• AWWA/APHA Standard Methods must be validated for use in the pharmaceutical industry.
• The microbial counts recommended in USP <1231> for purified water and water for injection are scientifically justified.
• Points of use must be sanitized with alcohol prior to sampling.
• Thermophilic bacteria can be found in pharmaceutical grade waters.
• Purified water must not contain any Gram-negative bacteria.
• Water for Injection must be produced by distillation.
• Exceeding the bacterial count level of less than 10 CFU per 100 mL for water for injection will result in bacterial endotoxin contamination.
• Rapidly circulating water in a purified water system will control the formation of bacterial biofilms.This review article will explore some of these common misconceptions and offer other positions.
It has been reported that microorganisms live social lives. They can use coordinated chemical and physical interactions to form complex communities. These communities are very intricate systems which coordinate microbial behavior. Little has been known about how these systems work in nature. Newer technologies, like microfluidics, are now available to better understand the small microbial communities that exist, also called microenvironments. Microenvironments are defined by Wessel, et al. (2013) as “small, defined regions of the environment.In microbial communities, a microenvironment refers to the area immediately surrounding a single cell or small group of cells and is generally distinct from its environs on the basis of characteristics such as nutrient availability and mass transfer.” This has resulted in a greater knowledge of the micro-bial behavior and phenotypic heterogenicity that exists in microbial colonies. (Wessel, et al.,2013)Biofilm is defined as a thin usually resistant layer of microorganisms (such as bacteria) that form on surfaces and can coat the surfaces. (Anonymous, 2018a) The microorganisms in a biofilm can be pa-thogenic or not and have formed complex multicellular structures on the surfaces. (Hall-Stoodley, et al., 2005) Previously, biofilm has been studied in the laboratory, using conventional methods inclu-ding growth on or in nutrient media. Understanding the communities where microorganisms live may provide us with additional information in preventing and remediating issues with biofilm.
The use of harvested rainwater in domestic hot water systems can result in optimised environmental and economic benefits to urban water cycle management, however, the water quality and health risks of such a scenario have not been adequately investigated. Thermal inactivation analyses were carried out on eight species of non-spore-forming bacteria in a water medium at temperatures rele-vant to domestic hot water systems (55–65 °C), and susceptibilities to heat stress were compared using D-values. The D-value was defined as the time required to reduce a bacterial population by 90% or 1 log reduction. The results found that both tested strains of Enterococcus faecalis were the most heat resistant of the bacteria studied, followed by the pathogens Shigella sonnei biotype A and Escherichia coli O157:H7, and the non-pathogenic E. coli O3:H6. Pseudomonas aeruginosa was found to be less resistant to heat, while Salmonella typhimurium, Serratia marcescens, Klebsiella pneu-moniae and Aeromonas hydrophila displayed minimal heat resistance capacities. At 65 °C, little thermal resistance was demonstrated by any species, with log reductions in concentration occurring within seconds. The results of this study suggested that the temperature range from 55 to 65 °C was critical for effective elimination of enteric/pathogenic bacterial components and supported the thesis that hot water systems should operate at a minimum of 60 °C.
This study compared the Quanti-DiscTM most probable number (MPN) test for heterotrophic bacteria from drinking water with the widely used yeast extract agar (YEA) pour plate method. The Quanti-DiscTM test module contains 50 reaction wells in which a medium has been pre-deposited. The medi-um contains a suite of three fluorogenic enzyme substrates selected for the detection of enzymes ex-pressed widely by heterotrophic bacteria. The MPN of heterotrophic bacteria is calculated from the number of fluorescing reaction wells after incubation of a sample. Quanti-DiscTM and the YEA pour plate method were compared according to guidance on comparing methods given in United Kingdom national guidance and ISO 17994:2004. The two methods were also challenged with reference strains and isolates of heterotrophic bacteria from drinking water. This indicated that heterotrophic bacteria commonly encountered in drinking water are detected by both the YEA pour plate method and Quanti-DiscTM. Analysis of data from split water samples (723 for 37 1C tests and 872 for 22 1C tests) from nine geographically diverse laboratories in England and Wales demonstrated that the Quanti-DiscTM method is equivalent to the YEA pour plate method for the analysis of heterotrophic bacteria from drinking and similar waters at 37 1C, and superior to YEA for the analysis at 22 1C. The Quanti-DiscTM method is a simple and efficient alternative method for the enumeration of heterotrophic bac-teria from drinking water.
Water treatment in the pharmaceutical industry com- monly involves highly developed technologies such as reverse osmosis (RO), ultrafiltration, UV irradia- tion, ion exchange (IX), and distillation. Elerodeionization (EDI) is a cost-effective water treatment method that is becoming increasingly standard. This article describes how and why the procedure is implemented in pharmaceutical water treatment plants.