Standard Disinfection Research Articles

Are surgical scrubbing and pre-operative disinfection of the skin in orthopaedic surgery reliable?

This study attempts to establish the actual effectiveness of pre-surgical disinfection of the patient and surgeon's hands. We evaluated bacterial density and composition on the skin of 15 patients undergoing knee arthroscopy and the left hand of two surgeons after standard disinfection with povidone-iodine. Three samples were taken after the first 6-min scrub in the first surgical operation from the periungual space of the 1 degrees finger, from the interdigital space between the 2 degrees and 3 degrees fingers and from the transverse palmar crest of the left hand of two surgeons for seven consecutive surgical sessions, for a total of 42 samples, and two samples from the pre-patellar skin and from the popliteal skin of 15 patients undergoing knee arthroscopy, for a total of 30 samples. Pre-surgical handwashing and disinfection procedures were identical in each case. Pre-surgical disinfection of the patient's skin with povidone-iodine was shown to be completely effective, with 100% of samples negative. Samples taken from the interdigital space and the palmar crest (100% of samples negative) demonstrated the efficacy of disinfection of the surgeon's hands with povidone-iodine, while the periungual space was contaminated in 50% of the samples. The bacterial strains isolated belong to the staphylococcus genus in 100% of the cases, with pathogenic strains in 29.6% of the cases. Standard pre-surgical disinfection of skin in areas easily accessible to the disinfectant is sufficient in itself to guarantee thorough sanitization. Standard scrubbing of the surgeon's hands is insufficient in eliminating bacterial contamination, including pathogenic germs, in the periungual space, where it is probably difficult for the disinfectant to come into contact with the skin.

Prions and Prion Diseases: Current Perspectives

Prion diseases, also known as transmissible spongiform encephalopathies, are rapidly progressive, uniformly fatal brain diseases that can infect humans and animals, including cattle, sheep, goats, mink, deer, elk, cats, and zoo ungulates. In humans, prion diseases can occur as a sporadic or inherited disease, or as a result of iatrogenic transmission. Prion diseases generated great public concern after an outbreak of bovine spongiform encephalopathy occurred in many European countries and scientific evidence indicated its transmission to humans. Research in prion diseases is hampered by certain unconventional properties of the presumed etiologic agent and the long incubation period associated with these diseases. Most conventional laboratory methods used to study viruses and bacteria may not be applicable. In the past, the etiologic agent of transmissible spongiform encephalopathies was believed to be a slow virus, primarily because of its transmissibility, ability to retain infectivity after filtration, and long incubation period. The successful transmission of scrapie, a centuries-old prion disease of sheep, to mice in 1961 greatly facilitated identification and characterization of the scrapie agent. Several characteristics of the scrapie agent suggest that the agent is not a virus but is likely composed primarily of a protein. The agent's characteristics include the absence of disease-specific nucleic acids; resistance to radiation, nucleases, and standard sterilization and disinfection methods; and inactivation by protein-modifying procedures. These observations and purification of the scrapie prion in the early 1980s led to widespread acceptance of the prion hypothesis. Since the 1980s, both the scope and nature of prion disease research has progressed rapidly. The economic and human cost associated with the bovine spongiform encephalopathy outbreak fueled the need to better understand the etiologic agent of prion diseases and their basic transmission mechanism. Prions and Prion Diseases: Current Perspectives summarizes the advances in prion disease research. It expands on a previous volume edited by David Harris that was published in 1999 under the title Prions: Molecular and Cellular Biology. The book's 10 chapters describe the biochemical and molecular features of prions and the normal prion protein, various laboratory methods for studying prions, and advances in the pathogenesis and immunology of prion diseases. Chapters 2 through 6 detail laboratory methods developed to study the unconventional agent of prion diseases. Chapter 2 describes a cell-free conversion reaction system to study how pathogenic prions associated with different interact with host cellular prion protein. Such systems have been used to study the biochemical mechanisms of prion diseases and can potentially be used to screen new therapies for their effectiveness against prion diseases. Chapter 3 describes the mechanisms underlying the biosynthesis and cell biology of the cellular prion protein by using cell culture systems. Understanding the detailed biochemical properties of the cellular prion protein will help show the molecular basis of its interaction with, and conversion to, the pathogenic prions. Subsequent chapters in the book describe other laboratory methods, including transgenic mouse models, which can be used to investigate the transmissibility of prions among different species, the extent and degree of the species barrier, the mechanism of prion propagation, and prion disease pathogenesis. Overall, the book provides a wealth of information on the progress made in understanding the molecular, immunologic, and genetic aspects of prion diseases and the laboratory methods used to study them. This book will be valuable to prion disease researchers, to scientists who want to gain more knowledge about the progress made in understanding the mechanisms of prion propagation, and to persons just beginning to study these unconventional, fatal brain diseases.

Current status of disinfection and sterilization for dental handpieces in the hospitals

To understand current status of the uses of dental handpieces, methods of disinfection and sterilization and their effectiveness in dental-care hospitals and out-patient departments of stomatology in general hospitals. Ten dental-care hospitals and departments of stomatology in general hospitals at varied levels were randomly sampled during 2000 to 2001 to investigate the uses of dental handpieces and means of their disinfection and sterilization. One used dental handpiece from each hospital or department of stomatology in general hospital selected was detected for possible contamination of bacteria by aerobic bacterial count and Coliform bacterial examinations and hepatitis B surface antigen (HBsAg) on it, based on "The Technical Standards for Disinfection" set by the Ministry of Health of China, and the effectiveness of its disinfection and sterilization was evaluated as well. Anti-suction handpieces were used only in 5.9% of the hospitals or departments, 94.1% of them without anti-suction devices. Cleansing disinfection was applied for used dental handpieces in 62.9% of the dental-care hospitals and the departments of stomatology, with an effective rate of 26.17%, immersing disinfection in 10.0%, with an effective rate of 55.88%, and autoclave in 27.1%, with an effective rate of 80.43%. Used dental handpieces in the hospitals and departments of stomatology in general hospitals were all contaminated by bacteria and HBsAg could be detected in 1.67% of them. Dental handpieces without anti-suction should be replaced soon by those with it or comprehensive dental unit with anti-suction device should be used. Used dental handpieces must be sterilized effectively before next use. Awareness on prevention from cross-infection should be improved for dental-care professional staff and operation of sterilization should be standardized.

The influence of endoscopic procedures upon the contamination of Helicobacter pylori cultures

Among the various diagnostic methods for the detection of Helicobacter pylori infection, histological examination and microbiological processing of gastric biopsy samples are assumed to be the gold standard techniques. Since H. pylori culture can be affected by the presence of non-H. pylori bacteria, we evaluated the efficacy of endoscope disinfection and the influence of endoscopic procedures on culture contamination. The procedures used during the first two routine endoscopies were evaluated during 28 consecutive days. Endoscopy room, forceps and endoscopic channel were analyzed before and after the beginning of normal procedures. After disinfection, a biopsy simulation was performed to verify the gastric bacteria. Endoscope disinfection removed all organisms from forceps and endoscopic channel with 100% efficacy. The most frequent non-H. pylori bacteria detected were Streptococcus bovis, Enterobacter hormaechei, and Staphylococcus aureus. The sensibility of the H. pylori culture was affected by the presence of non-H. pylori bacteria. The risk of transmission of microorganisms was not detectable when sterilized biopsy forceps and stringent disinfection standards were employed. Whilst S. bovis and E. hormaechei may be common in gastric microbial flora, the presence of P. aeruginosa and S. aureus indicated that the manipulation of biopsies could be responsible for culture contamination with these bacteria.

Risk of hepatitis B virus transmission by diagnostic hysteroscopy.

Few data are available in the literature concerning the efficacy of standard hysteroscope disinfection procedures to prevent hepatitis B transmission. The aim of the present study was to determine the risk of hepatitis B virus (HBV) transmission during hysteroscopy among anti-HBc-seropositive women. Serum and hysteroscopic samples were collected from 62 women after diagnostic hysteroscopy. All samples were tested for serologic HBV markers. Polymerase chain reactions (PCR) were carried out to amplify regions C and S of the viral genome and only samples amplified by both pairs of primers were considered to be positive. Anti-HBc was repeatedly reactive in 48 (77%) of 62 serum samples, and HBsAg was detected in 8 (13%). At least one HBV serologic marker was found in 49 (79%) samples. Only one sample was HBsAg positive and anti-HBc negative. HBV-DNA was detected by PCR in 7 serum samples but in only 3 hysteroscopic samples obtained just after hysteroscopy. It is noteworthy that high levels of anti-HBc IgM were detected in one HBsAg-negative patient who showed an HBV-DNA-positive hysteroscopic sample. An elevated sample/cut-off ratio for anti-HBc IgM suggests recent infection and reinforces the need for testing for HBsAg and anti-HBc before hysteroscopy, since acute hepatitis B can be clinically asymptomatic. Viral DNA was not detected in any hysteroscopic samples collected after washing and disinfecting procedures with glutaraldehyde. We conclude that HBV-DNA can be found in the hysteroscope soon after hysteroscopy, but standard disinfecting procedures are effective in viral removal.

Test models to determine cleaning efficacy with different types of bioburden and its clinical correlation

The importance of cleaning as a first crucial step in reprocessing instruments and endoscopes is recognized worldwide. However, no standards to determine the efficacy of cleaning have been established. We have therefore investigated Bodedex forte, a new cleaner, in various test models derived from critical types of bioburden on flexible endoscopes. Removal of dried blood from metal carriers was determined in comparison with standard instrument disinfectants. Removal of biofilm endotoxin from silicone test pieces and removal of dried X-ray contrast medium from polyethylene pieces was measured in comparison with one other standard cleaner. Residual bacteria in a biopsy channel from duodenoscopes following use of Bodedex forte, compared with two other cleaners, were measured in an endoscopy unit. After 15 min exposure to Bodedex forte, 95% of the dried blood were removed. Removal was between 0 and 86% with the disinfectants. Bodedex forte reduced endotoxin by 1.91+0.19 log 10-steps compared with 0.43+0.19 log 10-steps Cidezyme ( p<0.001; two-sided t-test). Removal of dried X-ray contrast medium was 99% with Bodedex forte and 94% with a conventional cleaner. No bacterial contamination after reprocessing was found in 98% of duodenoscopes with Bodedex forte (78 duodenoscopes), in 72% with a conventional cleaner (129 duodenoscopes) and in 69% with an enzymatic cleaner (100 duodenoscopes). The difference between the three cleaners was significant ( p<0.001; chi-squared test). The superiority of the cleaning capacity of the new cleaner was demonstrated in various test models, which were designed according to the clinical relevance of different bioburdens. Implementation of accepted and reproducible standards for testing the cleaning efficacy will remain a goal for the next years.

Efficiency of ampicillin and benomyl at controlling contamination of Annonaceae leaf segments culturedin vitro

Introduction . For the micropropagation of woody species, contamination of in vitro cultured explants is a constant problem, which can compromise the development of the technique. The aim of our study was to evaluate the effects of an antibiotic and a fungicide on surface and endophytic microorganisms associated with Annona cauliflora , A. bahiensis and A. glabra (Annonaceae) tissue culture. Materials and methods . Our work made it possible to compare a standard disinfection of in vitro cultured explants and the use of either a commercial fungicide, Benlate 500 (50% of benomyl) at (0.0, 1.0, 2.0 and 4.0) , or an antibiotic, ampicillin at (0.0, 1.0, 2.0 and 4.0) . Results . The study revealed considerable variations in the infection rates within species and according to the concentrations of benomyl and ampicillin used. Benomyl was effective at cleaning leaf segments, and, at a concentration of 1.0 , this fungicide was sufficient to eliminate all fungi. Ampicillin treatments at (0.0 to 4.0) were ineffective at controlling bacterial contamination. Conclusion . Referring to the difficulty in obtaining an aseptic in vitro culture starting from a woody species, the average number of healthy explants obtained after the disinfection of foliar explants of Annona sp. using the antimicrobial substances tested was significant. Further studies to evaluate the effects of the concentration of chemicals on in vitro plant regeneration for Annona species are needed to clarify the relationship between the concentration and phytotoxic effect of chemicals.

HYPOCHLORITE (1%) IS INEFFICIENT IN DECONTAMINATING BLOOD CONTAINING HYPODERMIC NEEDLES

Infectious biomedical waste and sharps have a potential hazard of transmission of pathogens. Among sharps, used needles form a major share and disinfection by 1 % hypochlorite is recommended in biomedical waste management rules of India. The aim of the present study was to evaluate the efficacy of hypochlorite for the decontamination of needles. Needles (16 g) filled with suspensions of standard strains and clinical isolates of gram positive and gram negative bacteria in plain normal saline and in human blood containing anticoagulant, were exposed to 1% hypochlorite and the surviving bacteria were subjected to viable counts. The observations indicated that 85 - 90 % of the needles filled with bacterial suspensions in saline are disinfected to a level of >5 log bacterial reduction (standard disinfection) on exposure to hypochlorite but only 15 to 30% needles contaminated with the challenge bacteria suspended in blood showed >5 log reduction in viable counts. Thus, hypochlorite treatment is inadequate for disinfecting needles contaminated with pathogenic bacteria in presence of blood and should not be recommended as an option for disinfection of the needles.

Parasite viability by electrorotation

The safety of water supplies is threatened by waterborne protozoan pathogens of man. Many of these pathogens are highly resistant to standard disinfection methods, have low infectivity doses and cause protracted disease. Single organisms subjected to a uniform rotating electric field acquire an induced electric dipole moment. The dipole and field interact and can produce a torque that makes the organism spin. The rate and direction of spin is a sensitive function of the dielectric properties of the organism and the suspending medium, namely the conductivity and permittivity. During a pathogen's lifecycle, numerous physico-chemical changes occur, which alter its dielectric properties. Electrorotation can detect these changes, enabling the viability of the pathogen to be determined. Using a microfabricated planar gold electrode array optimised for electrorotation and energised with quadrature sinusoidal voltages, we investigated the electrorotational properties of two protozoan parasites; Giardia muris and Cyclospora cayetanensis. We present differences in their electrorotational response due to viability, which was confirmed by vital dye assay for G. muris. Based on this work, we propose that electrorotation can be used to determine the viability of C. cayetanensis, for which no vital dye assays are available. The potential of this technique as a rapid and precise assay for the determination of parasite viability is particularly applicable to the food, water and healthcare industries. Furthermore, electrorotation is a non-invasive technique, allowing organisms to be further analysed using, for example, DNA sequencing, to establish likely pathogen sources.

Jaagsiekte sheep retrovirus Env protein stabilizes retrovirus vectors against inactivation by lung surfactant, centrifugation, and freeze-thaw cycling.

Jaagsiekte sheep retrovirus (JSRV) replicates in the lungs of sheep and causes the secretion of copious lung fluid containing the virus. Adaptation of JSRV to infection and replication in the lung and its apparent resistance to the denaturing activity of lung fluid suggest that vectors based on JSRV would be useful for gene therapy targeted to the lung. We show here that a retrovirus vector bearing the JSRV Env is stable during treatment with lung surfactant while an otherwise identical vector bearing an amphotropic Env is inactivated. Furthermore, the JSRV vector was stable during centrifugation, allowing facile vector concentration, and showed no loss of activity after six freeze-thaw cycles. However, the JSRV vector was inactivated by standard disinfectants, indicating that JSRV vectors pose no unusual safety risk related to their improved stability under other conditions.

Analysis of Lightning and BioClean tests for assessment of sanitation levels in pork production facilities

Objectives: To determine the test sensitivity and specificity of Lightning (BioControl Systems, Inc, Bellevue, Washington) and BioClean (BioVet, St Anthony, Minnesota) testing systems in determining whether various surfaces in pork production facilities have met the standards for disinfection; and to identify factors in pork production units which may interfere with the test sensitivity and specificity of Lightning or BioClean test results. Methods: Swab samples were collected from feeders, flooring, and walls in a wean-finish room and a nursery room of a 1600-sow, farrow-to-finish commercial operation. In both facilities, three adjacent swab samples of a 6.16 cm2 (0.955 in2) area were collected at each sampling site and analyzed using Lightning, BioClean, and cultural examination for bacteria. The test sensitivity and specificity of Lightning and BioClean tests were calculated for each surface using cultural examination as the "gold standard" for classifying a sample as clean or contaminated. Factors such as feed, manure, and disinfectant residues were tested to determine if they interfered with the test sensitivity and specificity of Lightning or BioClean tests. Results: Lightning tests were generally highly sensitive but had low specificity. BioClean tests were generally highly specific but had low sensitivity. Implications: Lightning and BioClean testing systems are not recommended for use in evaluating sanitation levels on swine farms without prior, independent, on-farm validation. Caution should be exercised when transferring technologies from other industries to pork production.

Wastewater disinfection by low-pressure UV and ozone: a design approach based on water quality

Disinfection processes are known to be very sensitive to wastewater quality. This paper discusses the parameters that impact the UV light (UV) and ozone disinfection processes and the related mechanisms based on literature review. Low-pressure UV and ozone technologies were investigated on effluents that covered a wide range of water quality. The results are given in terms of design doses required to meet three major disinfection standards. Both processes were found eligible for the majority of effluents tested. Although cost-effectiveness is usually considered more favourable to UV, the ozone alternative should be examined in cases such as the disinfection of low-quality effluents or large treatment plants. Ozonation was also found capable of meeting the stringent Title 22 standard with no coagulation at a dose of 10 mg/l.

Ozone disinfection of drinking water — technology transfer and policy issues

In today’s world of stricter drinking water disinfection standards there is a search for disinfection solutions that abide by the new standards while keeping the disinfection operation cost-efficient and safe. Ozone disinfection has the potential not only to meet but also to exceed the limits. Along with disinfection, the use of ozone for drinking water treatment can also have many other benefits such as taste and color removal, iron and manganese removal, and insecticide removal. p]Ozone disinfection has been used widely in Europe for well over a century, but many of its great benefits are just now being realized in the United States. Ozone disinfection has been the focus of many recent studies in the drinking water field. p]The purpose of the research for this paper was to analyze ozone disinfection from technology transfer and related policy perspectives. This paper reports the aspects used to analyze the technology as well as the results. A modified version of the Strategic Technology Evaluation Program was used to evaluate ozone disinfection’s transfer viability. p]This study has demonstrated that ozone disinfection, to be fully accepted into the drinking water industry, must first be accepted by the American Water Works Association, a nationally recognized professional and trade organization. Once this acceptance is gained, individual municipalities will more readily accept the technology. p]Another driving force that will likely bring about the adoption of ozone disinfection of drinking water would be stricter drinking water disinfection standards that can be best met by this technology.

E MERGENCY M EDICAL S ERVICES E QUIPMENT H YGIENE P RACTICES

Objective. To determine whether emergency medical services (EMS) systems adhere to accepted equipment hygiene standards. Methods. Mail surveys were sent to the physician medical directors of the EMS systems of the 125 most populous cities in the United States. Results. Eighty-five surveys (68%) were returned. Seventy-three (86%) of the responding services have a policy addressing equipment decontamination, and 32 of these (44%) have an accompanying quality assurance program. Seventy-nine (93%) utilize either alcohol or a commercial disinfectant (A/CD) on noncritical items when visibly contaminated with blood. However, only 32 of those agencies (41%) use soap and water in addition to A/CD. Another nine (11%) exchange contaminated items at the hospital, one (1%) uses other methods, and two (2%) respondents did not know. Seventy-six (89%) of the responding agencies perform endotracheal intubation. Of the 54 that decontaminate their own blades, 20 (37%) use soap and water in addition to A/CD, 32 (59%) use A/CD alone, and two (4%) use soap and water alone. Conclusion. Adherence to accepted hygiene standards among EMS systems in our most populous cities is poor. Many systems do not use soap and water prior to A/CD. Failure to do so may minimize the effectiveness of disinfection. Several systems use A/CD or soap and water alone, neither of which meets current standards for high-level disinfection recommended for items that will come in contact with mucous membranes, such as laryngoscope blades.

Reprocessing of gastrointestinal endoscopic accessories.

In this paper, the minimal standards for the disinfection of endoscopes and endoscopic accessories, as defined by the OMED's Minimal Standards for Disinfection, are described. Given the difficulties of disinfecting reusable accessories, disposable accessories are desirable and marketed by many companies. However, they are less economical than the reusable accessories available. Presently, both disposable and reusable forceps are marketed and those that are to be reused must be disinfected according to the Minimal Standards for Disinfection. This paper will discuss the factors to consider in choosing single-use or reusable accessories, such as economy, reliability of disinfection and durability of function. The one-time biopsy cost of reusable and disposable accessories that can be satisfactorily disinfected will also be compared. This paper concludes that the accessories used for endoscopic retrograde cholangiopancreatography are less reliably disinfected, less expensive and less durable compared with biopsy forceps.

Levels of bacterial contamination affecting podiatric equipment

This study aimed to ascertain the efficacy of standard equipment disinfection procedures by quantifying the level of bacterial contamination during a busy podiatric clinic. Sixteen cubicles were randomly paired and the footrest of the patient’s chair, the light handle and the trolley were sampled over 8 weeks at three times during the day; before the first patient (prior to disinfection), immediately after disinfection with a standard hard surface preparation and again at the end of the day. A template and the cotton swab technique were employed to obtain samples and control swabs. The swabs were plated, incubated aerobically and the number of colony forming units was counted. Samples from three cubicles were investigated further for the presence of pathogens. The contamination level decreased on all equipment following disinfection and the change was significant for the light handle and trolley (P<0.01). Contamination levels increased significantly on all equipment between the first disinfection and the end of the day (P<0.01). The light handle was the most contaminated and the footrest the least. Control swabs were negative for growth. Staphylococcus aureus was identified at different sampling times on all equipment and on the light handle after apparent disinfection. Coagulase negative staphylococci and Bacillus were also identified. While equipment disinfection initially had a significant impact on bacterial contamination, this was not maintained throughout the day. Disinfection procedures proved ineffective in eliminating the pathogen S.aureus, which raises concerns regarding the risk of cross-infection. Cleaning and disinfection procedures require review, audit and reinforcement. Particular attention should be given to disinfection of the light handle.

Evaluation of a disinfection procedure for hysteroscopes contaminated by hepatitis C virus.

We assessed the ability of a standard disinfection procedure to eliminate hepatitis C virus (HCV) from the air-water channel of hysteroscopes. The residual HCV RNA remaining after the disinfection procedure was measured by polymerase chain reaction. When correctly applied to hysteroscopes, the standard disinfection procedure was sufficient to eliminate the risk of HCV transmission.

Overview of residual disinfection practice by European water suppliers

Abstract This paper summarises the current approach to disinfection in different European countries, and describes some of the factors that will drive change. Historically, the wide diversity in water resource availability and supply infrastructure across the Continent, as well as disinfection philosophy, have all influenced disinfection practice. However, in the future new EU regulatory standards for disinfection by¬products and customer pressure for improved water taste, will also have a growing impact. The paper reviews the fundamental principles of disinfection, both at source and in the distribution network, and highlights the critical issue of balancing microbial risk against achievement of low disinfection by-product levels and acceptable tastes for customers, New technology is facilitating moves towards low or even zero disinfectant residuals, However, whilst the goal of zero network residuals and high standards of microbiological safety has already been achieved in some parts of Europe, in many supply systems this will only be possible at significant cost.

Detection of persistent vegetative bacteria and amplified viral nucleic acid from in-use testing of gastrointestinal endoscopes

Hospital-acquired infection attributed to inadequate decontamination of gastrointestinal endoscopes prompted an in use evaluation of recommended procedures. Specimens were obtained from the internal channels of 123 endoscopes before, during and after decontamination by flushing with saline and brushing with a sterile brush, and examined for vegetative bacteria by broth and plate culture. Four endoscopy units were tested; the chemical disinfectants used were: 2% glutaraldehyde in Centres 1 and 2 (automated) and Centre 3 (manual); peracetic acid in Centre 4 (automated). Samples from patients in Centre 1 with known chronic hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV-1) infection were also examined for viral nucleic acid by ultracentrifugation, nucleic acid extraction, reverse transcription (for RNA) and polymerase chain reaction (PCR). No persistent vegetative bacteria were found following standard manual cleaning and disinfection for 20 min in 2% glutaraldehyde in Centres 2 and 3 ( N = 37). At Centre 1, while plate culture yielded no growth, 34% of samples ( 10 29 ) grew vegetative bacteria in broth culture after cleaning and disinfection for 20 min in 2% glutaraldehyde. Investigation revealed an error in manual cleaning; no bacteria were detected in 37 samples taken after this was corrected. At Centre 4, despite the use of peracetic acid as a sterilant, three out of 20 (15%) of post decontamination samples grew bacteria; one contained persistent bacteria. HBV and HCV PCR analysis detected viral nucleic acid in three out of four and four out of six samples from viraemic patients undergoing endoscopy in Centre 1 during the period of improper manual washing. After proper cleaning was instituted, samples from nine out of nine HCV viraemic patients were negative. HIV RNA was detected in five of 14 samples taken from endoscopes after use on HIV positive patients but all post decontamination samples were negative. Detection of bacteria in washes from endoscope channels is a useful warning of a breakdown in decontamination practice. Inadequate brushing of internal channels may result in persistent HCV and HBV viral nucleic acid, the significance of which is not clear. These results reinforce the importance of adequate manual cleaning of endoscopes before chemical disinfection.

Outbreak of Legionnaire's Disease Linked to a Decorative Fountain by Molecular Epidemiology

The incubation period of Legionnaires' disease in five patients was traced to attendance at conventions in a hotel in the Orlando, Florida, area between January 6 and February 2, 1992. The five case patients (mean age, 69 years) were older than 55 randomly chosen controls (mean age, 53 years) who had also attended one of the same conventions (p = 0.007). All case patients were males, as were 40% of the controls (p = 0.01). No significant differences in exposures were found between case patients and controls, but all case patients and 65% of the controls reported exposure to a decorative fountain in the hotel lobby. Water from the fountain was the only one of 55 environmental specimens to test positive for Legionella. Both the environmental isolate and the only clinical isolate were Legionella pneumophila serogroup 1, with identical patterns identified on monoclonal antibody subtyping and pulsed-field gel electrophoresis (PFGE) of genomic restriction fragments. The fountain's recirculating system had been irregularly maintained, and water in the fountain may have been heated by submersed lighting. These findings demonstrate the utility of monoclonal antibody subtyping and PFGE of genomic restriction fragments in assessing the significance of environmental isolates of L. pneumophila, especially when other epidemiologic findings are inconclusive. They also show that decorative fountains may be a potential source of infection with L. pneumophila, and emphasize the need for standard maintenance and disinfection procedures.