Symptomatic androgen deficiency develops only when both total and free testosterone decline in obese men who may have incident biochemical secondary hypogonadism: prospective results from the EMAS

Objective: Limited evidence supports the use of free testosterone (FT) for diagnosing hypogonadism when sex hormone binding globulin (SHBG) is altered. Low total testosterone (TT) is commonly encountered in obesity where SHBG is typically decreased. We aimed to assess the contribution of FT in improving the diagnosis of symptomatic secondary hypogonadism (SH), identified initially by low total testosterone (TT), and then further differentiated by normal FT (LNSH) or low FT (LLSH). Design: Prospective observational study with a median follow‐up of 4.3 years. Patients: 3369 community‐dwelling men aged 40‐79 years from eight European centres. Measurements: Subjects were categorised according to baseline and follow‐up biochemical status into persistent eugonadal (referent group; n=1880), incident LNSH (eugonadism to LNSH; n=101) and incident LLSH (eugonadism to LLSH; n=38). Predictors and clinical features associated with the transition from eugonadism to LNSH or LLSH were assessed. Results: The cumulative incidence of LNSH and LLSH over 4.3 years was 4.9% and 1.9% respectively. Baseline obesity predicted both LNSH and LLSH but the former occurred more frequently in younger men. LLSH, but not LNSH, was associated with new/worsened sexual symptoms, including low desire [OR= 2.67 (1.27‐5.60)], erectile dysfunction [OR= 4.53 (2.05‐10.01)] and infrequent morning erections [OR= 3.40 (1.48‐7.84)]. Conclusions: These longitudinal data demonstrate the importance of FT in the diagnosis of hypogonadism in obese men with low TT and SHBG. The concurrent fall in TT and FT identifies the minority (27.3%) of men with hypogonadal symptoms, which were not present in the majority developing low TT with normal FT

Continuous culture models to study pathogens in biofilms

A multi-stage continuous culture apparatus has been constructed to model mono-species biofilms and high species diversity biofilm consortia found in clinical practice, the natural environment and the built environment. New artificial saliva and urine media were developed, and natural and treated potable waters obtained, for the defined, reproducible generation of the biofilms containing bacterial and protozoal pathogens on various hydroxyapatite, plastic, metal and paint-covered substrata over many months. Following several modifications to the design, each chemostat vessel, linked in series or parallel, consists of a titanium top plate containing a variety of insertion ports for the monitoring electrodes, and addition/removal of gases, media, effluent, pH and redox titrants, antibacterial agents and coupon substrata for biofilm generation. Each top plate is clamped to a 1 liter glass vessel, containing the culture medium, and mounted on a stirrer with a heater pad to facilitate external heating and stirring, controlling the shear rate across the immersed coupons. There are few internal parts to go wrong. The growth rate is controlled by continuous addition of medium to the planktonic and sessile phases of the cultures. These model systems are ideal for generating biofilms either aerobically or anaerobically, and containing microaerophilic or anaerobic species, even in highly aerated media

Rapid detection of biofilms and adherent pathogens using scanning confocal laser microscopy and episcopic differential interference contrast microscopy

Knowledge of biofilm structure and function has changed significantly in the last few years due to advances in light microscopy. One pertinent example is the use of scanning confocal laser microscopy (SCLM) to visualise corrosion pits caused by the biofilm mosaic footprint on corroding metal surfaces. Nevertheless, SCLM has some limitations as to its widespread use, including cost, inability to observe motile bacteria and eukaryotic grazers within biofilms, and difficulty to scan a curved surface. By contrast, episcopic differential interference contrast (EDIC) microscopy has provided a rapid, real time analysis of biofilms on opaque, curved, natural or man-made surfaces without the need for cover slips and oil. EDIC, coupled with epi-fluorescence (EDIC/EF), microscopy has been used successfully to visualise the 3-D biofilm structure, physiological niches, protozoal grazing and iron biomineralization, and the location of specific pathogens such as Legionella pneumophila, Campylobacter jejuni and Cryptosporidium parvum. These species were identified using gold nanoparticles or fluorophores coupled to monoclonal antibodies or 16S rRNA probes, respectively. Among its many potential uses, the EDIC technique will provide a rapid procedure to facilitate the calibration of the modern generation of biofilm-sensing electrodes

The physico-chemistry of biofilm-mediated pitting corrosion of copper pipe supplying potable water

Copper is a generally robust material that has beneficial properties to reduce biofilm formation and pathogen colonisation of pipes supplying potable water. However, a rare pitting corrosion can occur in soft, poorly buffered waters that can lead to pipe failure. This has been shown to be mediated by a copper-tolerant biofilm whose physical and chemical heterogeneity can establish microenvironments for corrosion potentials, causing micro pits that eventually coalesce into large perforations through the pipe wall. Control of the biofilm, for example through reduced cold water or elevated hot water temperatures, can suppress this corrosion phenomenon

Human coronavirus 229E remains infectious on common touch surface materials

The evolution of new and reemerging historic virulent strains of respiratory viruses from animal reservoirs is a significant threat to human health. Inefficient human-to-human transmission of zoonotic strains may initially limit the spread of transmission, but an infection may be contracted by touching contaminated surfaces. Enveloped viruses are often susceptible to environmental stresses, but the human coronaviruses responsible for severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) have recently caused increasing concern of contact transmission during outbreaks. We report here that pathogenic human coronavirus 229E remained infectious in a human lung cell culture model following at least 5 days of persistence on a range of common nonbiocidal surface materials, including polytetrafluoroethylene (Teflon; PTFE), polyvinyl chloride (PVC), ceramic tiles, glass, silicone rubber, and stainless steel. We have shown previously that noroviruses are destroyed on copper alloy surfaces. In this new study, human coronavirus 229E was rapidly inactivated on a range of copper alloys (within a few minutes for simulated fingertip contamination) and Cu/Zn brasses were very effective at lower copper concentration. Exposure to copper destroyed the viral genomes and irreversibly affected virus morphology, including disintegration of envelope and dispersal of surface spikes. Cu(I) and Cu(II) moieties were responsible for the inactivation, which was enhanced by reactive oxygen species generation on alloy surfaces, resulting in even faster inactivation than was seen with nonenveloped viruses on copper. Consequently, copper alloy surfaces could be employed in communal areas and at any mass gatherings to help reduce transmission of respiratory viruses from contaminated surfaces and protect the public health.Importance: respiratory viruses are responsible for more deaths globally than any other infectious agent. Animal coronaviruses that “host jump” to humans result in severe infections with high mortality, such as severe acute respiratory syndrome (SARS) and, more recently, Middle East respiratory syndrome (MERS). We show here that a closely related human coronavirus, 229E, which causes upper respiratory tract infection in healthy individuals and serious disease in patients with comorbidities, remained infectious on surface materials common to public and domestic areas for several days. The low infectious dose means that this is a significant infection risk to anyone touching a contaminated surface. However, rapid inactivation, irreversible destruction of viral RNA, and massive structural damage were observed in coronavirus exposed to copper and copper alloy surfaces. Incorporation of copper alloy surfaces in conjunction with effective cleaning regimens and good clinical practice could help to control transmission of respiratory coronaviruses, including MERS and SAR

Survival of gastric and enterohepatic Helicobacter spp. in water: implications for transmission

Part of the reason for rejecting aquatic environments as possible vectors for the transmission of Helicobacter pylori has been the preference of this microorganism to inhabit the human stomach and hence use a direct oral-oral route for transmission. On the other hand, most enteric bacterial pathogens are well known for being able to use water as an environmental reservoir. In this work, we have exposed 13 strains of seven different Helicobacter spp. (both gastric and enterohepatic) to water and tracked their survival by standard plating methods and membrane integrity assessment. The influence of different plating media and temperatures and the presence of light on recovery was also assessed. There was good correlation between cultivability and membrane integrity results (Pearson's correlation coefficient = 0.916), confirming that the culture method could reliably estimate differences in survival among different Helicobacter spp. The species that survived the longest in water was H. pylori (>96 h in the dark at 25°C), whereas H. felis appeared to be the most sensitive to water (<6 h). A hierarchical cluster analysis demonstrated that there was no relationship between the enterohepatic nature of Helicobacter spp. and an increased time of survival in water. This work assesses for the first time the survival of multiple Helicobacter spp., such has H. mustelae, H. muridarum, H. felis, H. canadensis, H. pullorum, and H. canis, in water under several conditions and concludes that the roles of water in transmission between hosts are likely to be similar for all these species, whether enterohepatic or not

How clean is clean?

There are approximately 6.5 million surgical procedures performed within England each year. These procedures are spread across the 182 acute NHS trusts which themselves cover the 249 hospitals with sterile service departments (SSDs) in England (NHS Estates, 2001). Of concern has been the emergence of evidence that highly robust infectious agents such as the Scrapie-form of the prion protein (PrPsc), causing variant or sporadic Creuztfeldt-Jakob disease, may remain viable following standard hospital decontaminating procedures (Taylor, 1999). This led the Department of Health to issue revised guidelines on the decontamination of instruments (Health Service Circulars 1999 178 and 1999 179) in August 1999. However, it is clear that subsequent and ongoing monitoring of cleaning standards must be maintained in order to ensure the highest decontamination standards are reached and maintained, and therefore reduce any possibility of nosocomial infection

Current limitations about the cleaning of luminal endoscopes

Background: The presence and potential build up of patient material such as proteins in endoscope lumens can have significant implications, including toxic reactions, device damage, inadequate disinfection/sterilisation, increased risk of biofilm development and potential transmission of pathogens. Aim: We intended to evaluate the potential protein deposition and removal in the channels of flexible luminal endoscopes during a simple contamination/ cleaning cycle. Methods: We evaluated the level of contamination present on disposable endoscopy forceps which come in contact with the lumen of biopsy channels. Following observations in endoscopy units, we evaluated some factors influencing protein adsorption inside luminal endoscope channels and the action of current initial cleaning techniques using a proteinaceous test soil and very sensitive fluorescence epimicroscopy. Findings: Disposable endoscope accessories appeared likely to contribute to the contamination of lumens and were useful indicators of the amount of proteinaceous soil transiting through the channels of luminal endoscopes. Enzymatic cleaning according to the manufacturer’s recommendations and brushing of the channels were ineffective at removing all proteinaceous residues from new endoscope channels after a single contamination. Rinsing applied immediately after contamination only slightly improved decontamination outcome. Conclusion: Limited action of current decontamination procedures and the lack of applicable quality control methods to assess channel cleanliness between each patient contribute to increasing the risk of cross infection of potentially harmful microorganisms and molecules during endoscopy procedures