RESUMEN
Collaboration between clinical laboratories in different countries is widespread but rarely subject to critical analysis. We developed a management tool for assessing the quality of an international pathology laboratory collaboration. Key areas of activity were identified and relevant performance indicators were established. There was no evidence of improved staff morale arising from the project but research, education, equipment, protocols and ethics activities all had demonstrable outputs. Identification of suboptimal performance in areas of the project allowed effective improvement planning. International collaboration may consume significant resources. Objective assessment should be used to measure performance and to enhance quality.
Asunto(s)
Cooperación Internacional , Laboratorios/normas , Patología Clínica/normas , Garantía de la Calidad de Atención de Salud/métodosRESUMEN
This two-year prospective hospital population-based study of candidaemia is the first to be conducted in the UK. It was carried out on behalf on the British Society for Medical Mycology (BSMM) as part of the European Confederation of Medical Mycology (ECMM) epidemiological survey of candidaemia. Six hospitals in England and Wales acted as sentinel hospitals. Main outcome measures were hospital population-based incidence and 30-day mortality. There were 18.7 episodes of candidaemia per 100,000 finished consultant episodes or 3.0/100,000 bed days and 45.4% cases occurred in intensive care unit (ICU) patients. Candida albicans was isolated in 64.7% of confirmed cases. The majority of isolates were sensitive to standard antifungal agents, including fluconazole. The overall 30-day mortality was 26.4% and removal of the central venous catheter was associated with a significant reduction in mortality. In conclusion, the incidence of candidaemia in England and Wales is similar to that of the USA, the majority of isolates remain sensitive to commonly used antifungal agents and mortality associated with this infection appears to be falling.
Asunto(s)
Antifúngicos/farmacología , Candida/efectos de los fármacos , Candidiasis/epidemiología , Evaluación de Resultado en la Atención de Salud , Adolescente , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Candida/clasificación , Candida/aislamiento & purificación , Candidiasis/etiología , Candidiasis/mortalidad , Candidiasis/prevención & control , Niño , Preescolar , Infección Hospitalaria/epidemiología , Infección Hospitalaria/etiología , Infección Hospitalaria/mortalidad , Infección Hospitalaria/prevención & control , Farmacorresistencia Fúngica , Inglaterra/epidemiología , Femenino , Humanos , Incidencia , Lactante , Recién Nacido , Control de Infecciones/métodos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Estudios Prospectivos , Vigilancia de Guardia , Gales/epidemiologíaAsunto(s)
Celulosa/análogos & derivados , Celulosa/farmacología , Glicerol/farmacología , Neisseria gonorrhoeae/efectos de los fármacos , Fosfatos/farmacología , Glicoles de Propileno/farmacología , Cremas, Espumas y Geles Vaginales/farmacología , Técnicas de Tipificación Bacteriana/métodos , Femenino , Gonorrea/diagnóstico , Humanos , Lubrificación , Manejo de Especímenes , Vagina/microbiologíaRESUMEN
A nested PCR based diagnostic assay for the detection of toxoplasmosis was devised in 1990 and was used successfully among a battery of tests for the clinical diagnosis of Toxoplasma gondii infection since 1991. However, it was reported that the assay produced false positive diagnoses with Nocardia asteroides infection. Investigation of this phenomenon showed that although cross reactivity with some unrelated organisms may be observed when altered conditions are employed, the assay does not lead to misdiagnosis if performed under the appropriate, stringent conditions.
Asunto(s)
Genes Protozoarios , Reacción en Cadena de la Polimerasa/métodos , Toxoplasma/genética , Toxoplasmosis/diagnóstico , Actinomyces/genética , Animales , Secuencia de Bases , Diagnóstico Diferencial , Electroforesis en Gel de Agar , Genes Bacterianos , Genes Fúngicos , Humanos , Datos de Secuencia Molecular , Mycobacterium tuberculosis/genética , Nocardia/genética , Sensibilidad y EspecificidadRESUMEN
High-level gentamicin-resistant enterococci present problems in the treatment of infected patients, especially as synergy between penicillin and gentamicin is lost. Previous studies have suggested various risk factors for the acquisition of these enterococci. A case-controlled study was performed on 17 patients infected with resistant enterococci and 26 infected with sensitive strains who attended a London hospital. The key risk factors for acquisition of infection with high-level gentamicin-resistant enterococci were found to be prior prolonged antibiotic treatment, use of five or more antibiotics, and the presence of a urinary catheter. It is proposed that infection control measures should be targeted at patients at higher risk. In addition, control of antibiotic usage in a hospital may help to prevent acquisition and spread of these organisms.
Asunto(s)
Enterococcus/efectos de los fármacos , Gentamicinas/uso terapéutico , Infecciones por Bacterias Grampositivas/tratamiento farmacológico , Adolescente , Adulto , Anciano , Estudios de Casos y Controles , Niño , Preescolar , Farmacorresistencia Microbiana , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Estudios Retrospectivos , Factores de RiesgoRESUMEN
AIM: To investigate cross contamination of blood cultures associated with multiple use venting devices, which are widely used in clinical microbiology laboratories to reduce labour costs. METHODS: Systematic analysis of 13,880 blood culture results in a large teaching hospital where multiple use venting devices were employed. RESULTS: Nine series of potential cross contamination were identified in a 12 month period. Four series involved coagulase negative staphylococci and were unlikely to represent true cross contamination. Five series involved blood cultures which had significant bacterial growth at the time of venting. CONCLUSIONS: Multiple use venting devices can be associated with cross contamination of blood cultures. This may result from contamination of the internal lumen of the venting device which is not exposed to the biocide. Medical microbiologists should consider the possibility of cross contamination associated with venting procedures when interpreting blood culture results. Further development of multiple use venting devices is required to reduce the risk of cross contamination of cultures.
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Contaminación de Equipos , Técnicas Microbiológicas/instrumentación , HumanosRESUMEN
AIM: To quantify Toxoplasma gondii DNA using a specially constructed artificial template as competitor in a nested polymerase chain reaction (PCR). METHODS: The diagnostic assay was a nested PCR employing four primers that amplify part of the single copy gene for the P30 major surface antigen in T gondii. An artificial competitor containing the four primer binding sites was made first by creating a 216 bp deletion in the native 914 bp full length PCR product using restriction enzyme digestion, ligation of selected digestion fragments, and cloning the ligation product into an E coli plasmid vector for production. Competitive nested PCR using three different quantities of T gondii genomic DNA with four corresponding 10-fold dilutions of the artificial competitor was then performed, and the results visualised with agarose gel electrophoresis. A standard curve was drawn by plotting the T gondii to competitor ratio readings against log10 of the competitor readings. RESULTS: The band intensities on agarose gel showed quantitative amplification in competitive nested PCR. The amount of competitor required to achieve equal molar amounts of PCR products is calculated by reading off the value of the competitor where the T gondii to competitor ratio equals 1 on the standard curves. CONCLUSIONS: Competitive PCR is possible with a nested assay, and quantitative amplification is well preserved. The use of an artificial competitor containing the same primer binding sites as the target enables the absolute amount of T gondii DNA in unknown samples to be estimated. In addition, the competitor simultaneously serves as a control for detecting false negative results of failed reactions in individual assay runs.
Asunto(s)
ADN Protozoario/análisis , Reacción en Cadena de la Polimerasa/métodos , Toxoplasma/aislamiento & purificación , Toxoplasmosis/diagnóstico , Animales , Electroforesis en Gel de Agar , HumanosRESUMEN
Congenital toxoplasmosis is associated with acute maternal infection acquired during or shortly before the pregnancy. The mother's infection is initiated by the ingestion of one of the life forms of the parasite but the relative importance of the different sources of toxoplasmosis are not established. Recent epidemiological studies have confirmed ingestion of raw meats as a risk factor but also identified consumption of cured meats as being associated with acute toxoplasmosis in pregnancy. There is little existing information concerning the efficiency of commercial curing processes for inactivating Toxoplasma gondii. We sought to detect the presence of T. gondii in ready-to-eat cured meat samples by amplification of the parasite's P30 gene using the polymerase chain reaction (PCR). In addition, tissue culture was used in order to isolate viable parasites. Laboratory inoculated specimens were used to assess the sensitivity of each method. PCR was able to detect parasite contamination down to a level of 5 x 10(3) trophozoites/g while viable toxoplasma could be detected in tissue culture at a level of 10(3) trophozoites/g cured meat. The high salt content of some cured meats limited sensitivity of the PCR assay by inhibition of the polymerase enzyme and reduced the sensitivity of tissue culture due to osmotic pressure causing cytopathic effect. However viable T. gondii was detected in one out of 67 ready-to-eat cured meat samples. Our results highlight the need for improved methods for detecting toxoplasma contamination of food. Health implications of consuming cured meats in pregnancy require careful consideration.
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Manipulación de Alimentos , Carne/parasitología , Toxoplasma/aislamiento & purificación , Animales , Células Cultivadas , Femenino , Manipulación de Alimentos/métodos , Humanos , Concentración de Iones de Hidrógeno , Reacción en Cadena de la Polimerasa , Embarazo , Complicaciones Parasitarias del Embarazo/prevención & control , Factores de Riesgo , Sensibilidad y Especificidad , Porcinos , Toxoplasmosis Congénita/prevención & controlRESUMEN
The clinical sequelae of acute and congenital toxoplasmosis are well established, but that of chronic toxoplasma infection remains uncertain. In rodents, chronic toxoplasma infection is associated with altered behaviour leading to an enhanced risk of feline predation and a putative selective advantage to the parasite. It is proposed that neurotropic cysts of toxoplasma exert an effect on animal behaviour, either directly or via the release of metabolic products. Long-standing toxoplasma infection in humans has been linked to cerebral tumour formation and personality shift. In view of the vast population with chronic toxoplasma infection, further studies of the clinical sequelae of this condition are required.
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Síntomas Conductuales/parasitología , Vectores de Enfermedades , Estadios del Ciclo de Vida , Trastornos de la Personalidad/parasitología , Toxoplasma/crecimiento & desarrollo , Toxoplasmosis Animal/complicaciones , Toxoplasmosis/complicaciones , Animales , Conducta Animal , Gatos , Enfermedad Crónica , Femenino , Humanos , Ratones , Embarazo , Ratas , Toxoplasmosis Congénita/transmisiónRESUMEN
An audit was undertaken to determine case compliance with prenatal testing and investigation of infants for toxoplasma infection. Subsequently, the effect of enhanced reference unit Intervention was studied. The proportion of cases of toxoplasma infection associated with pregnancy completing an investigation programme was calculated. The effect of continued and short-term additional intervention was assessed and reasons for failure to comply were sought. The status of the child was established in 30% of cases when acute maternal toxoplasma infection was detected. Continuous reference unit intervention significantly improved case compliance to 45% over a 3-year period, but the effect was lost when the additional measures were withdrawn. Failure to complete the investigation procedure was associated with loss of patient-clinician contact and clinician/laboratory error. Enhanced intervention did not result in a significant improvement in compliance with the investigation programme for babies with clinical abnormality. The benefits of testing for toxoplasma infection associated with pregnancy are limited by failure to complete necessary investigations.
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Auditoría Médica , Complicaciones Parasitarias del Embarazo/terapia , Toxoplasmosis Congénita/prevención & control , Toxoplasmosis/terapia , Adulto , Inglaterra , Femenino , Humanos , Cooperación del Paciente , Pacientes Desistentes del Tratamiento , Embarazo , Diagnóstico Prenatal , Toxoplasmosis Congénita/diagnósticoRESUMEN
Current serological tests do not discriminate between asymptomatic latent Toxoplasma gondii infection and reactivating toxoplasmosis, but timely therapeutic intervention before the development of symptoms would lead to major reductions in morbidity and permanent disability. This study developed a new enzyme-linked immunosorbent assay (ELISA) for antibody to T. gondii tissue cyst antigens and screened tissue cyst antigens by Western blot analysis to test the hypothesis that antibody recognition of T. gondii tissue cyst-derived antigen is a good indicator of reactivation disease. A total of 187 sera was tested by Sabin-Feldman dye test and tissue cyst ELISA, AIDS patients and patients with ocular disease were considered separately, as the exposure to parasite antigens may be different in these two groups. The dye test did not discriminate between immunocompetent and immunocompromised T. gondii seropositive patients or between active and quiescent toxoplasmosis. Tissue cyst ELISA demonstrated a raised specific antibody response in immunocompetent T. gondii seropositive patients and in quiescent HIV positive sera. These data support th view that the tissue cyst population is in a state of dynamic equilibrium. It is proposed that, in the immunocompetent host, tissue cyst development and rupture are under some degree of immune control, but that in the immunocompromised host this equilibrium is disturbed and reactivation disease results. Data from patients with reactivating ocular toxoplasmosis demonstrate that tissue cyst-specific antibody levels are not different in active and quiescent disease and indeed they are not significantly different from immunocompetent T. gondii seronegative sera. In the Western blot analysis of 57 HIV positive patient sera, eight antigens (65, 57, 49, 47, 36, 28, 26 and 18 kDa) were consistently recognised by one third or more of the sera tested, but no single antigen was diagnostic of quiescent or active toxoplasmosis. It is concluded that tissue cyst-derived antigens are not a reliable serological marker of reactivating toxoplasmosis.
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Anticuerpos Antiprotozoarios/sangre , Antígenos de Protozoos/inmunología , Toxoplasma/inmunología , Toxoplasmosis/inmunología , Infecciones Oportunistas Relacionadas con el SIDA/inmunología , Infecciones Oportunistas Relacionadas con el SIDA/parasitología , Animales , Anticuerpos Antiprotozoarios/inmunología , Biomarcadores , Western Blotting , Ensayo de Inmunoadsorción Enzimática , Humanos , Inmunocompetencia , Huésped Inmunocomprometido , Estudios Retrospectivos , Toxoplasma/crecimiento & desarrollo , Toxoplasmosis/parasitología , Toxoplasmosis Cerebral/inmunología , Toxoplasmosis Cerebral/parasitología , Toxoplasmosis Ocular/inmunología , Toxoplasmosis Ocular/parasitologíaRESUMEN
In a one month period in the summer of 1993 a community outbreak of Escherichia coli O157 infection affected six children living within an area of 1.5 miles radius in south west London. Three children developed haemolytic uraemic syndrome, one of whom died. E. coli O157 phage type 2 was isolated from faeces in five cases and serological tests showed the sixth child had antibodies to E. coli O157 lipopolysaccharide. E. coli O157 phage type 2 was isolated from a faecal specimen from this child's mother who was a secondary case. Three of the cases, whose onset dates were within three days of each other, had all been exposed to a paddling pool where disinfection procedures were found to be inadequate. Samples of water taken from this pool contained E. coli, although not the O157 serotype. A fourth case had played at a different paddling pool in the three days before becoming ill. Action has been taken to improve disinfection procedures at municipal paddling pools in the London borough concerned.
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Infecciones por Escherichia coli/epidemiología , Piscinas , Adulto , Niño , Preescolar , Control de Enfermedades Transmisibles/métodos , Escherichia coli/aislamiento & purificación , Infecciones por Escherichia coli/transmisión , Femenino , Microbiología de Alimentos , Síndrome Hemolítico-Urémico/epidemiología , Humanos , Londres/epidemiología , Masculino , Microbiología del AguaRESUMEN
An outbreak of cryptosporidiosis which affected 44 people in January and February 1991 was identified through local surveillance at a South London Public Health Laboratory. Preliminary enquiries revealed that more than half the patients were adult and that there were no common factors other than geographical association. A case-control study showed a significant association between illness and consumption of tap water supplied by a particular water company, as well as a dose response effect. There were no apparent breaches or irregularities in the water distribution system and no indication of a problem through routine monitoring indices. This incident demonstrates the problems of establishing the source of cryptosporidiosis outbreaks in the absence of evidence of environmental abnormality, as well as possibly indicating that water conforming to current treatment standards may occasionally contain sufficient numbers of Cryptosporidium oocysts to cause sporadic cases or clusters.
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Criptosporidiosis/etiología , Cryptosporidium , Brotes de Enfermedades , Microbiología del Agua , Adolescente , Adulto , Anciano , Animales , Estudios de Casos y Controles , Niño , Preescolar , Criptosporidiosis/epidemiología , Interpretación Estadística de Datos , Femenino , Humanos , Lactante , Londres/epidemiología , Masculino , Persona de Mediana Edad , Vigilancia de la Población , Factores de Riesgo , Agrupamiento Espacio-Temporal , Encuestas y CuestionariosRESUMEN
Congenital toxoplasmosis is an established cause of abortion, neonatal disease and ocular defects presenting in later life. Preventative options include health education, immunization and screening of pregnant women and infants with appropriate management of cases found to be at risk. Screening requires a knowledge of the disease, the test, the treatment and the administration of the proposed programme. Treatment can be directed towards the acutely infected mother, the infected fetus or infant and the patient with an acute exacerbation of ocular toxoplasmosis following congenital infection. Harm-benefit assessment of screening programmes designed to prevent congenital toxoplasmosis has produced conflicting results. Further research is required into the incidence of acute toxoplasmosis in pregnancy and subsequent congenital infection, the frequency of neonatal handicap, precise tests for the diagnosis of recent maternal infection and the presence of congenital toxoplasmosis and improved treatment of the infection.
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Toxoplasmosis Congénita/prevención & control , Femenino , Educación en Salud , Humanos , Recién Nacido , Tamizaje Masivo , Embarazo , Complicaciones Parasitarias del Embarazo/prevención & control , Toxoplasmosis/prevención & control , Toxoplasmosis Congénita/diagnósticoRESUMEN
OBJECTIVE: To determine the incidence of acute symptomatic toxoplasma retinochoroiditis presenting to ophthalmologists for patients born in Britain and elsewhere. DESIGN: Population based, cross sectional study. SETTING: 11 districts in south Greater London. SUBJECTS: All patients presenting to NHS ophthalmologists with symptoms due to acute toxoplasma retinochoroiditis in 1992-3. MAIN OUTCOME MEASURE: Intraocular inflammation in association with a retinochoroidal scar, active adjoining retinitis, and IgG serum antibodies to toxoplasma. RESULTS: The estimated incidence of acute symptomatic retinochoroiditis for all people born in Britain was 0.4/100,000/year. If a mean of two symptomatic episodes per lifetime is assumed, 100 people born in Britain may be affected each year, about a fifth of the estimated 500-600 congenitally infected people born each year. CONCLUSIONS: A substantial proportion of people with acute symptomatic toxoplasma retinochoroiditis were born outside the country, and the number born in Britain was smaller than the number previously estimated to develop retinochoroidal lesions due to congenital toxoplasmosis. These findings suggest that prenatal screening for toxoplasmosis in Britain may be of limited benefit.
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Coriorretinitis/etnología , Toxoplasmosis Ocular/etnología , Enfermedad Aguda , Adolescente , Adulto , África Occidental/etnología , Coriorretinitis/congénito , Coriorretinitis/parasitología , Estudios Transversales , Femenino , Humanos , Incidencia , Londres/epidemiología , Masculino , Toxoplasmosis Ocular/congénitoAsunto(s)
Infección Hospitalaria/microbiología , Infecciones por Bacterias Gramnegativas/microbiología , Unidades de Cuidado Intensivo Neonatal , Antibacterianos/farmacología , Técnicas Bacteriológicas , Farmacorresistencia Microbiana , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Gramnegativas/crecimiento & desarrollo , Humanos , Vigilancia de la PoblaciónRESUMEN
We have examined laboratory reports of toxoplasmosis received by the PHLS Communicable Disease Surveillance Centre between January 1981 and December 1992 in order to describe epidemiological trends in the three main clinical manifestations of toxoplasmosis-lymphadenopathy, eye disease, and neurological disease; and the two most important risk groups-fetuses and people whose immunity is impaired. The total numbers of reports each year did not change significantly between 1981 and 1992 and were similar to the numbers between 1976 and 1980, but different trends emerged in each subgroup. Reports of acute lymphadenopathic toxoplasmosis declined in children and young adults and eye disease associated with toxoplasmosis fell markedly in all age groups. Reports of neurological disease and severe toxoplasmosis complicating impaired immunity, due mainly to HIV infection or transplant surgery, rose. Reports of infections diagnosed in pregnancy rose steeply in the late 1980s although reports of congenital toxoplasmosis were no more common than in 1975 to 1980. Reports of acute toxoplasmosis came mainly from southern England. The emergence of these diverse trends from apparently unchanging totals emphasises the importance of surveillance systems capable of discrimination.