RESUMEN
BACKGROUND: Biofilm formation has been shown to be associated with damaged areas of endoscope channels. It was hypothesized that the passage of instruments and brushes through endoscope channels during procedures and cleaning contributes to channel damage, bacterial attachment and biofilm formation. AIM: To compare surface roughness and bacterial attachment in used and new endoscope channels in vivo and in vitro. METHODS: Surface roughness of 10 clinically used (retired) and seven new colonoscope biopsy channels was analysed by a surface profiler. For the in-vitro study, a flexible endoscope biopsy forceps was passed repeatedly through a curved 3.0-mm-diameter Teflon tube 100, 200 and 500 times. Atomic force microscopy was used to determine the degree of inner surface damage. The number of Escherichia coli or Enterococcus faecium attached to the inner surface of the new Teflon tube and the tube with 500 forceps passes in 1 h at 37oC was determined by culture. RESULTS: The average surface roughness of the used biopsy channels was found to be 1.5 times greater than that of the new biopsy channels (P=0.03). Surface roughness of Teflon tubes with 100, 200 and 500 forceps passes was 1.05-, 1.12- and 3.2-fold (P=0.025) greater than the roughness of the new Teflon tubes, respectively. The number of E. coli and E. faecium attached to Teflon tubes with 500 forceps passes was 2.9-fold (P=0.021) and 4.3-fold (P=0.004) higher compared with the number of E. coli and E. faecium attached to the new Teflon tubes, respectively. CONCLUSION: An association was found between endoscope usage with damage to the biopsy channel and increased bacterial attachment.
Asunto(s)
Adhesión Bacteriana , Endoscopios/microbiología , Enterococcus faecium/fisiología , Contaminación de Equipos/prevención & control , Escherichia coli/fisiología , Biopelículas/crecimiento & desarrollo , Desinfección/métodos , Politetrafluoroetileno , Propiedades de SuperficieRESUMEN
We predicted that biofilm would form on surfaces of endoscope tubing in contact with fluids, and may be difficult to remove by current washing procedures. Its presence may protect micro-organisms from disinfectant action and contribute to failure of decontamination prior to re-use. Tubing samples removed from 13 endoscopes that had been sent to an endoscope-servicing centre were examined for the presence of biofilm and bacteria by scanning electron microscopy. Biological deposits were present on all samples tested. Biofilm (bacteria plus exopolysaccharides matrix) was present on the suction/biopsy channels of five of 13 instruments, and was very extensive on one of these. Bacteria and microcolonies were often but not necessarily associated with surface defects on the tubing. All 12 air/water channels examined showed biofilm, and this was extensive on nine samples. Routine cleaning procedures do not remove biofilm reliably from endoscope channels, and this may explain the unexpected failure of decontamination encountered in practice despite good adherence to infection control guidelines.
Asunto(s)
Bacterias , Biopelículas , Infección Hospitalaria/prevención & control , Descontaminación/normas , Endoscopios/microbiología , Contaminación de Equipos , Adhesión a Directriz , Bacterias/aislamiento & purificación , Bacterias/ultraestructura , Humanos , Nueva Gales del SurRESUMEN
This study examines the formation of bacterial biofilms on percutaneous wires used for fracture fixation. Twelve control (clinically uninfected) wires and ten infected wires were collected and examined using broth culture and scanning electron microscopy. Three of the 12 control wires grew Staphylococcus spp. with very low bacterial counts in their percutaneous portions. In the clinically infected wires, six wires in four subjects had positive cultures in their percutaneous portions and four of these also had positive cultures in their deep portions with much higher bacterial counts than the controls. In two patients (four wires) treated with antibiotics, cultures were negative except for the percutaneous portion of one wire. Scanning electron microscopy did not reveal bacterial biofilm formation, but biological deposit without bacteria was noted on most wires. During the 6 weeks of fracture fixation, some bacterial colonization of wires occurred, but bacteria did not form biofilms which may increase bacterial resistance to systemic antibiotics, cause implant loosening and act as a source of late infection.
Asunto(s)
Biopelículas/crecimiento & desarrollo , Hilos Ortopédicos/microbiología , Fijación de Fractura/efectos adversos , Fracturas del Radio/microbiología , Fracturas del Radio/cirugía , Staphylococcus/crecimiento & desarrollo , Staphylococcus/fisiología , Infección de la Herida Quirúrgica/microbiología , Hilos Ortopédicos/efectos adversos , Recuento de Colonia Microbiana , Humanos , Microscopía Electrónica de Rastreo , Estudios Prospectivos , Fracturas del Radio/fisiopatología , Staphylococcus/aislamiento & purificación , Infección de la Herida Quirúrgica/etiología , Infección de la Herida Quirúrgica/fisiopatologíaRESUMEN
Every laboratory needs personnel who work 24 hours a day 7 days a week, are efficient, obedient, capable of showing initiative, insightful and affable. Our experience of laboratory workers tells us that there is an immense way to go to achieve these goals. Having tired of the normal, Darwinian approach, a project has been initiated to achieve these ends through genetic technologies.
Asunto(s)
Personal de Laboratorio Clínico , Investigación , HumanosRESUMEN
AIM: Steam autoclaving is the gold standard for decontaminating dental instruments, but worldwide disinfection is still widely employed. We have evaluated a range of procedures for their ability to inactivate duck hepatitis B virus contaminating dental syringes. METHODS: Residual infectivity of virus suspensions following 2% glutaraldehyde treatment, ultrasonication or steam sterilisation at 121 degrees or 134 degrees was assayed by injecting day-old ducklings and examining their livers for viral DNA 2.5 weeks later. Dental syringes were contaminated with DHBV positive blood, then treated by the same methods. An anaesthetic cartridge containing water was loaded into the syringe and 400microl aliquots used to inject day-old ducklings. Used dental syringes were examined by Scanning Electron Microscopy. RESULTS: Suspension test:- ultrasonic treatment failed to inactivate DHBV in suspension, but complete inactivation was achieved by 2% glutaraldehyde and autoclaving. Syringe test:- neither ultrasonic treatment nor glutaraldehyde inactivated DHBV. Autoclaving at 134 degrees (3 minutes) permitted transmission to 1/16 ducklings but steam sterilisation at 121 degrees (15 minutes) was effective. Electronmicroscopy demonstrated organic debris (biofilm) in the lumen of used syringes. CONCLUSION: Short autoclaving cycles, albeit at raised temperatures, may fail to inactivate the virus because of poor steam penetration, inadequate heat transfer and the accumulation of protective biofilm.
Asunto(s)
Descontaminación/métodos , Desinfectantes Dentales , Virus de la Hepatitis del Pato , Control de Infección Dental/métodos , Jeringas/virología , Animales , Patos , Glutaral , Calor , Humanos , Microscopía Electrónica de Rastreo , Vapor , Esterilización/métodos , UltrasonidoRESUMEN
This study has defined the effects of cell concentration, culture conditions and mitogen concentration on the uptake of 3H-labelled thymidine by mononuclear cells (SMC) purified from the spleens of ducks. The mitogen stimulation of cultures containing from 5 x 10(2) to 2 x 10(6) cells per well or more took up 3H-thymidine without the need for mitogenic stimulation. The response to each mitogen tested--phytohaemagglutinin (PHA), concanavalin A (ConA) and lipopolysaccharide (LPS)--was distinctive, with between duck variation in the time for peak stimulation, the level of stimulation with PHA, the response to ConA was variable and the response to LPS was poor. Supplementation of the media with 20 per cent fetal calf serum instead of autologous duck serum was satisfactory.
Asunto(s)
Patos/inmunología , Mitógenos/farmacología , Monocitos/efectos de los fármacos , Bazo/efectos de los fármacos , Animales , División Celular/efectos de los fármacos , División Celular/fisiología , Células Cultivadas , Concanavalina A/farmacología , Relación Dosis-Respuesta a Droga , Lipopolisacáridos/farmacología , Monocitos/citología , Monocitos/metabolismo , Fitohemaglutininas/farmacología , Bazo/citología , Bazo/fisiología , Timidina/metabolismo , Timidina/farmacocinética , TritioRESUMEN
The effects of extracts of five Australian Phyllanthus species (P. hirtellus, P. gunnii, P. gasstroemii, P. similis and P. tenellus), other plant extracts and the antiviral drug foscarnet on duck hepatitis B virus (DHBV) endogenous DNA polymerase (DNAp) activity were compared. All 5 Phyllanthus species caused 50% inhibition at concentrations of dry weight between 350-800 micrograms/ml, which is comparable with the effect described for P. amarus on the DNAp of human and woodchuck hepatitis B viruses. Incubation of P. hirtellus with 100 ID50 DHBV neutralized infection. However, neither P. gasstroemi extract, given by intraperitoneal injection (i.p.) at a dose of 20 mg/kg 3 times per week to ducklings early in the incubation period, or P. hirtellus extract, given to established DHBV carrier ducklings, prevented or eliminated infection.