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Biomedical subjects

J V Lee

Publications and source records attributed to J V Lee.

At least 19 recordsLinked to original sources
PubMed2006

Legionnaires' disease outbreak associated with a cruise liner, August 2003: epidemiological and microbiological findings.

Eight cases of Legionnaires' disease were identified among the 215 German passengers after a cruise to the Nordic Sea in August 2003. An unmatched case-control study was conducted to identify risk factors and the source of infection. In total, eight passengers fulfilled the case definition, one of these died. Forty-two passengers served as controls. The attack rate was 4%. The mean age was 60 years for cases and 62 years for controls. Prolonged exposure to the spa pool seemed to be a risk factor of infection (OR 4.85, P=0.09). Legionella pneumophila serogroup 1, monoclonal antibody (mAb) subgroup 'Knoxville' was isolated from clinical and environmental samples. DNA sequence-based typing revealed that these isolates were indistinguishable from each other. The investigation showed the importance of an interdisciplinary approach of microbiology and epidemiology as not all sites on the ship that tested positive for L. pneumophila actually posed a relevant risk for the passengers.

Adult↗
PubMed2006

Culture of Helicobacter pylori from domestic water samples--the impact of strain variation on growth on solid and in liquid media.

Helicobacter pylori is an important global human pathogen and there is growing evidence from PCR assays that contaminated drinking water might be a possible source of infection in some circumstances. There are no validated protocols for direct isolation but various culture media have been developed for possible environmental sampling. Our aim here was to investigate how inter-strain variation might affect the interpretation of results with such media. Two laboratory adapted reference strains and four recent clinical isolates were tested on four solid media and in ten liquid media. Considerable variation was found between strains in their ability to recover on the different media after stress exposure (suspension in sterile tap water). Generally, clinical isolates were less robust than the laboratory-adapted strains and, overall, the former required longer recovery times. Our findings highlighted the importance of using a range of isolates for evaluations, as examination of laboratory-adapted strains alone did not provide an accurate representation of the utility of media that may be used to recover H. pylori from water.

Culture Media↗
PubMed2004

Detection of Helicobacter pylori by PCR but not culture in water and biofilm samples from drinking water distribution systems in England.

AIMS: To investigate treated water distribution systems in England as a source of Helicobacter pylori. METHODS AND RESULTS: Water and biofilms were obtained from 11 domestic and seven educational properties and from hydrants, reservoirs and water meters supplied by three water utilities. Samples were cultured on nonselective and antibiotic containing media combined with immunomagnetic separation concentration. Viable helicobacters were not detected in any of the 151 samples but Helicobacter-specific PCR assays detected DNA in 26% of samples from domestic properties, schools and hydrants with the highest frequency in biofilms (42%). Direct sequencing of six selected amplicons confirmed >95% sequence homology to H. pylori. CONCLUSIONS: While viable helicobacters were not isolated, evidence was obtained for the presence of Helicobacter DNA, including that of H. pylori. Biofilms on surfaces within water distribution systems may act either as sites for the passive accumulation of helicobacters or as potentially important reservoirs of infection. SIGNIFICANCE AND IMPACT OF THE STUDY: Our findings strengthen evidence that H. pylori may be transmitted through drinking water. However, there is currently no evidence that viable cells can survive the disinfection levels used in UK mains supplies and the health risk from this source remains unclear.

Base Sequence↗
PubMed2004

Comparison of agar-based methods for the isolation and enumeration of heterotrophic bacteria with the new multidose IDEXX SimPlate method.

Pour and spread plates are the conventional methods of choice for the isolation and enumeration of heterotrophic microorganisms in treated water supplies. The tests are performed at 22 degrees C and 37 degrees C for 72 h and 48 h respectively. Counts at 22 degrees C are associated with pollution of water systems from external sources, while counts at 37 degrees C are used as an indication of treatment plant performance and the deterioration of the general quality of water. Conventional methods using Yeast Extract Agar for a pour plate and R2A agar for a spread plate were compared with the multidose IDEXX SimPlate method for the isolation and enumeration of heterotrophic bacteria in water. SimPlate gave a significantly higher count on average than the conventional methods. The R2A method showed the next highest count, being significantly higher than Yeast Extract Agar. In addition, unlike the pour and spread plate methods, SimPlate was easier to use, reduced labour, and the test results were far easier to read.

Agar↗
PubMed2003

Community-acquired Legionnaires' disease in Nottingham--too many cases?

The aim of this study was to compare the incidence of community-acquired Legionnaires' Disease in Nottingham with England and Wales and to explore reasons for any difference observed. Based on data from the National Surveillance Scheme for Legionnaires' Disease (1980-1999), the rate of infection in England and Wales was 1.3 per million/year compared with 6.6 per million/ year in Nottingham. Domestic water samples were obtained from 41 (95%) of 43 Nottingham cases between 1997 and 2000. In 16 (39%) cases, Legionella sp. were cultured in significant quantities. Proximity to a cooling tower was examined using a 1:4 case-controlled analysis. No significant difference in the mean distance between place of residence to the nearest cooling tower was noted (cases 2.7 km vs. controls 2.3 km; P = 0.5). These data suggest that Nottingham does have a higher rate of legionella infection compared to national figures and that home water systems are a source.

Adolescent↗
PubMed2003

A comparison of the International Standards Organisation reference method for the detection of coliforms and Escherichia coli in water with a defined substrate procedure.

AIMS: This study investigated the use of the International Standards Organisation (ISO) procedure for the comparison of microbiological methods. Using this procedure the ISO reference procedure for the detection of coliforms and Escherichia coli in water was compared with a defined substrate method (ColilertTM). METHODS AND RESULTS: A total of 20 laboratories from 13 European countries compared the use of Colilert/Quanti-TrayTM, a quantitative defined substrate test (DST) for the presence of coliforms and E. coli with the ISO reference procedure, which utilizes tergitol-TTC medium. Results of the study showed that DST detected significantly more coliforms and E. coli than did the reference procedure. In the case of E. coli the recoveries were also higher when using DST and the difference seen was statistically significant. The confirmation rate obtained when using the DST product suggested that no confirmation of wells positive for E. coli was necessary during routine use. CONCLUSIONS: Colilert is a suitable alternative to the ISO reference procedure for the detection of coliforms and E. coli in water. The methods used during the comparison study indicated that confirmation of all colonies/positive wells led to the most accurate information and it is recommended that for future comparison studies this should become standard practice. Confirmation of a small proportion of colonies led to misleading conclusions and should be avoided when comparing microbiological methods. SIGNIFICANCE AND IMPACT OF STUDY: It has been demonstrated that the ISO reference procedure fails to detect a significant proportion of coliforms and E. coli in drinking water. Colilert/QuantiTrayTM is a more suitable alternative.

Bacteriological Techniques↗
PubMed2002

Guidelines for investigating single cases of Legionnaires' disease.

These guidelines for the investigation of single cases of legionnaires' disease have been updated from those produced in 1994 to take account of developments in microbiological and environmental diagnostic capabilities and the recognition that infection may be acquired from the patient's domestic water system. The new guidelines recommend that when a case of legionnaires' disease has been diagnosed, it should be investigated to determine whether it is part of an outbreak or cluster, work related, suspected to be a hospital acquired infection or is travel associated. If information concerning the patient's movements during the incubation period shows it to be none of these, then appropriate environmental investigations should be considered which might include the patient's domestic water system as a potential source of infection. The guidelines are designed to provide advice and information to all public health personnel involved in the control and prevention of legionnaires' disease.

Communicable Disease Control↗
PubMed2000

Detection of Legionella pneumophila using a real-time PCR hybridization assay.

A real-time PCR hybridization assay for Legionella pneumophila is described; the assay uses LightCycler (Idaho Technology) methodology to specifically detect 2.5 CFU/reaction, equivalent to 1,000 CFU/liter of starting water sample. The assay, including DNA extraction and confirmation of product identity, is completed within 90 min of receipt of a sample.

DNA, Bacterial↗
PubMed1997

Mixed genogroup SRSV infections among a party of canoeists exposed to contaminated recreational water.

Samples of faeces collected from a party of canoeists involved in a gastroenteritis outbreak were examined by electron microscopy and RT-PCR for evidence of infection with SRSVs. A broadly reactive primer pair was used to detect SRSVs followed by application of genogroup-specific primers to SRSV-positive specimens. Exposure data were collected by means of a questionnaire. SRSVs were detected in 1/4 specimens examined by EM and 3/4 by RT-PCR. Genogrouping, and sequencing of PCR products revealed two distinct strains: a genogroup I strain, related to the Desert Shield virus, and a genogroup II strain, related to the Lordsdale virus to be associated with the outbreak. Exposure data indicated that capsising and eating food before getting changed were associated with an increased risk of gastroenteritis and was consistent with infection following the consumption of contaminated water. This study confirms the greater sensitivity of RT-PCR for the diagnosis of SRSV infections and its utility, when incorporating genogroup-specific primers, in establishing more complex epidemiological data.

Adolescent↗
PubMed1994

Influence of temperature and plumbing material selection on biofilm formation and growth of Legionella pneumophila in a model potable water system containing complex microbial flora.

Survival and growth of Legionella pneumophila in both biofilm and planktonic phases were determined with a two-stage model system. The model used filter-sterilized tap water as the sole source of nutrient to culture a naturally occurring mixed population of microorganisms including virulent L. pneumophila. At 20 degrees C, L. pneumophila accounted for a low proportion of biofilm flora on polybutylene and chlorinated polyvinyl chloride, but was absent from copper surfaces. The pathogen was most abundant on biofilms on plastics at 40 degrees C, where it accounted for up to 50% of the total biofilm flora. Copper surfaces were inhibitory to total biofouling and included only low numbers of L. pneumophila organisms. The pathogen was able to survive in biofilms on the surface of the plastic materials at 50 degrees C, but was absent from the copper surfaces at the same temperature. L. pneumophila could not be detected in the model system at 60 degrees C. In the presence of copper surfaces, biofilms forming on adjacent control glass surfaces were found to incorporate copper ions which subsequently inhibited colonization of their surfaces. This work suggests that the use of copper tubing in water systems may help to limit the colonization of water systems by L. pneumophila.

Bacterial Adhesion↗
PubMed1994

Influence of Plumbing Materials on Biofilm Formation and Growth of Legionella pneumophila in Potable Water Systems.

A two-stage chemostat model of a plumbing system was developed, with tap water as the sole nutrient source. The model system was populated with a naturally occurring inoculum derived from an outbreak of Legionnaires' disease and containing Legionella pneumophila along with associated bacteria and protozoa. The model system was used to develop biofilms on the surfaces of a range of eight plumbing materials under controlled, reproducible conditions. The materials varied in their abilities to support biofilm development and the growth of L. pneumophila. Elastomeric surfaces had the most abundant biofilms supporting the highest numbers of L. pneumophila CFU; this was attributed to the leaching of nutrients for bacterial growth from the materials. No direct relationship existed between total biofouling and the numbers of L. pneumophila CFU.

Journal Article↗
PubMed1993

Outbreak of Legionnaires' disease at University Hospital, Nottingham. Epidemiology, microbiology and control.

Twelve patients in a large teaching hospital contracted Legionnaires' disease over a period of 11 months. The source was a domestic hot water system in one of the hospital blocks, which was run at a temperature of 43 degrees C. Five different subtypes of Legionella pneumophila serogroup 1 have been isolated from water in different parts of the hospital, over a period of time. Only one subtype, Benidorm RFLP 14, was implicated in disease. Circumstantial evidence suggested that the outbreak may have been due to recent colonization of the hot water system with a virulent strain of Legionella pneumophila. The outbreak was controlled by raising the hot water temperature to 60 degrees C, but careful surveillance uncovered two further cases in the following 30 months. Persistent low numbers of Legionella pneumophila were isolated from the domestic hot water of wards where Legionnaires' disease had been contracted, until an electrolytic unit was installed releasing silver and copper ions into this supply.

Adult↗
PubMed1991

An outbreak of Legionnaires' disease in Gloucester.

Fourteen people living in or near the city of Gloucester fell ill with Legionnaires' disease caused by Legionella pneumophila serogroup (SG) 1 between 27 August and 27 October 1986. Another patient had fallen ill on 30 May. Nine of the 15 were diagnosed retrospectively during a case finding exercise. There were three deaths. Three cases of Pontiac fever were also diagnosed. The source was probably one or more wet cooling towers. Nineteen premises in the city with such towers were identified, and three just outside Gluocester. Samples from 11 of the 22 premises grew Legionella spp.; from nine of these L. pneumophila SG 1 (Pontiac) was isolated. The efficacy of regular addition of biocide in addition to hypochlorite added at the time of disinfection in inhibiting the growth of Legionella spp. was demonstrated. A survey of patients' movements during their likely incubation period showed that there was no single building that all patients had visited, but there were two areas of the city which nearly all had visited or passed through by car. A case-control study demonstrated an association with one of these areas. Cooling towers near both areas may have been sources but the evidence is insufficient to incriminate any single one. The unexpected finding of L. pneumophila SG 1 (Pontiac) in nine towers supports the hypothesis that there may have been multiple sources. Cooling towers may have been contaminated by mains water or by drift from other towers.

Adult↗