Escherichia coli is a routinely used microbiological indicator of water quality. To determine whether holding time and storage conditions had an effect on E. coli densities in surface water, studies were conducted in three phases, encompassing 24 sites across the United States and four commonly used monitoring methods. During all three phases of the study, E. coli samples were analyzed at time 0 and at 8, 24, 30, and 48 h after sample collection. During phase 1, when 4°C samples were evaluated by Colilert or by placing a membrane onto mFC medium followed by transfer to nutrient agar containing 4-methylumbelliferyl-␤-D-glucuronide (mFC/NA-MUG), three of four sites showed no significant differences throughout the 48-h study. During phase 2, five of seven sites showed no significant difference between time 0 and 24 h by membrane filtration (mFC/NA-MUG). When evaluated by the Colilert method, five of seven sites showed no significant difference in E. coli density between time 0 and 48 h. During phase 3, 8 of 13 sites showed no significant differences in E. coli densities between time 0 and the 48-h holding time, regardless of method. Based on the results of these studies, it appears that if samples are held below 10°C and are not allowed to freeze, most surface water E. coli samples analyzed by commonly used methods beyond 8 h after sample collection can generate E. coli data comparable to those generated within 8 h of sample collection. Notwithstanding this conclusion, E. coli samples collected from surface waters should always be analyzed as soon as possible.Escherichia coli testing is an important tool used by public health experts for the prevention of waterborne disease. The detection of E. coli in a water sample from an environmental source provides direct evidence of fecal contamination. Regulatory agencies are increasingly requiring more emphasis on E. coli testing as part of programs aimed at curtailing waterborne disease. Holding time and temperature can have a significant impact on the density of microbiological indicators at the time of sample analysis (4, 5, 7). Recommendations for E. coli holding times range from 8 h (2, 3, 9) to 24 h (8), and holding temperatures below 10°C are generally considered acceptable (2,3,8,9). It is also recommended that when transport conditions result in delays longer than 6 h, the use of field laboratory facilities located at the site of collection or delayed incubation procedures be considered (2). The Surface Water Treatment Rule requirements of the U.S. Environmental Protection Agency (USEPA) for total coliform and fecal coliform monitoring of surface water used as drinking water sources (3) specify that the time from sample collection to initiation of analysis is not to exceed 8 h; the regulations also encourage (but do not require) drinking water system personnel to hold samples at below 10°C during transit.Unfortunately, data from evaluations of microbiological indicator density that support current holding time recommendations are limited, particularly for E. coli....

Biofilms have been implicated in a variety of nosocomial infections associated with medical devices, hospital equipment, and other hard surfaces. In addition, household and workplace surfaces such as sinks, countertops, toilets, and cutting boards can act as reservoirs. This study's objective was to identify and evaluate literature reporting resistance to antimicrobial agents in biofilm populations. These review findings suggest that the research evaluating resistance in biofilms could be grouped into the following three mechanisms: (1) physicochemical barriers; (2) biological factors; and (3) phenotypic changes. Current research has identified potential mechanisms of antimicrobial resistance, but there is no clear evidence supporting any one mechanism. Moreover, no reported studies examine the potential impact of biofilms on biosafety practices and the public health risk of infectious diseases from biofilms in healthcare facilities and the workplace environment. Future research directions in biofilms are likely to focus on: (a) imaging of biofilms in situ, (b) in vitro and in vivo models of biofilms, (c) genetic, metabolic, and immunologic probes for real-time analysis, (d) antimicrobial resistance in multispecies biofilms, and (e) identification and characterization of phenotypic modifications. In our assessment, these studies will provide the basis to develop guidelines for biofilm-related biosafety and public health risk assessment. Applied Biosafety, 10(2) pp. 83-90

We assessed the effectiveness and potential environmental impact of a yeast-based deoxygenation process considered for treating ship ballast waters to reduce the risk of aquatic species introduction. Laboratory experiments were conducted to test three treatment concentrations (0.33%, 0.67% and 1.0% v v−1) at five temperatures (4, 10, 15, 20 and 25 °C) in both fresh- and saltwater, with and without mixing. Complete anoxia (<0.3 mg L−1) was achieved in all experiments, and there were no significant differences in effectiveness between fresh- and saltwater or between mixing levels. Time to hypoxia was inversely related to temperature, ranging from half a day at 25 °C to nearly 7 days at 4–5 °C. The process can quickly generate and maintain anoxic conditions over a long enough period of time to effectively eliminate a wide variety of aquatic organisms. Results of six bioassays indicated that treated waters were not toxic at the end of experiments and would not pose a toxic risk to natural receiving waters. Increased concentrations of ammonia, organic carbon and particulate matter resulting from yeast production in treated waters may cause some potential adverse environmental effects. The practicality of implementing this process for treating ballast water in ships is discussed.

In the United States, the use and disposal of biosolids are regulated under 40 CFR part 503. Subpart D of this regulation protects public health and the environment through requirements designed to reduce the potential for contact with pathogens in biosolids applied to land or placed in a surface disposal site. For Class A biosolids, the 503 regulations require evaluation of either fecal coliforms or Salmonella, and may include enumeration of enteric viruses, or viable helminth ova. In order to demonstrate compliance, precise measurement of microbial contaminants is a necessity. However, interlaboratory comparisons of standard protocols were not available when the 503 regulations were promulgated. or relative percent difference (RPD). Prior to analyses, two different types of outlier tests were performed to remove datathat were not representative of the overall laboratory performance observed during the studies, in accordance with ASTM protocol.Microbiological method performance generally is difficult to assess. Method recoveries can be problematic due to uneven distribution of organisms in suspension and densitiesof organisms can change between enumeration and spiking. The QC criteria developed for the fecal coliform and Salmonella methods will allow laboratories to assess laboratory and method performance, identify and solve problems, and assess quality of occurrence results.

The U.S. Environmental Protection Agency's (EPA) Water Laboratory Alliance relies on the Centers for Disease Control and Prevention's ultrafiltration-based Water Processing Procedure (WPP) for concentration of biosafety level 3 (BSL-3) agents from 10 L to 100 L of drinking water. The WPP requires comprehensive training and practice to maintain proficiency, resulting in a critical need for quality control (QC) criteria. The aim of this study was to develop criteria using male-specific (MS2) coliphage (BSL-2 agent) to minimize safety hazards associated with BSL-3 agents and to use the criteria to evaluate analytical proficiency during a demonstration exercise. EPA Method 1602 with EasyPhage was used during the study to develop QC criteria for 100-mL, and 40-100 L samples. The demonstration exercise indicated that the MS2 criteria would allow laboratories to demonstrate proficiency using the WPP with 40-100 L samples. In addition, the QC criteria developed for 100-mL samples has broad applicability at laboratories that are using MS2 for other types of analyses, such as assessment of water treatment devices. The development of MS2 QC criteria allows laboratories to develop and confirm ongoing proficiency using the WPP.