Identifying patients at increased risk of non-ventilator-associated pneumonia on admission to hospital: a pragmatic prognostic screening tool to trigger preventative action.

BACKGROUND: Non-ventilator healthcare-associated pneumonia (NV-HAP) is an important healthcare-associated infection. This study tested the feasibility of using routine admission data to identify those patients at high risk of NV-HAP who could benefit from targeted, preventive interventions. METHODS: Patients aged ≥64 years who developed NV-HAP five days or more after admission to elderly-care wards, were identified by retrospective case note review together with matched controls. Data on potential predictors of NV-HAP were captured from admission records. Multi-variate analysis was used to build a prognostic screening tool (PRHAPs); acceptability and feasibility of the tool was evaluated. RESULTS: A total of 382 cases/381 control patients were included in the analysis. Ten predictors were included in the final model; nine increased the risk of NV-HAP (OR between 1.68 and 2.42) and one (independent mobility) was protective (OR 0.48; 95% CI 0.30-0.75). The model correctly predicted 68% of the patients with and without NV-HAP; sensitivity 77%; specificity 61%. The PRHAPs tool risk score was 60% or more if two predictors were present and over 70% if three were present. An expert consensus group supported incorporating the PRHAPs tool into electronic logic systems as an efficient mechanism to identify patients at risk of NV-HAP and target preventative strategies. CONCLUSIONS: This prognostic screening (PRHAPs) tool, applied to data routinely collected when a patient is admitted to hospital, could enable staff to identify patients at greatest risk of NV-HAP, target scarce resources in implementing a prevention care bundle, and reduce the use of antimicrobial agents.

Changes in orthopaedic operating theatre practice, monitored using settle plates.

INTRODUCTION: The importance of ultraclean air in reducing deep infection was studied by Charnley who showed that the rate decreased as the airborne bacterial load was reduced. The effectiveness was shown in a large Medical Research Council (MRC) trial, but registry data have not shown a consistent benefit. Because we treat patients with rheumatoid arthritis, we decided to look at our theatre air quality. METHODS: In phase 1 we monitored air quality using settle plates, exposed for one hour after the incision, on the instrument trolleys in a joint replacement theatre. In phase 1 the scrub person did not wear a body exhaust system. In phase 2 all three staff used a body exhaust system, and we played close attention to the orientation and position of the surgical lights and trolleys. RESULTS: In phase 1 we grew 0.24 colonies/plate/hour in the ultraclean zone, which is comparable to the Charnley trial findings. In the second phase we grew 0.03 colonies/plate/hour (p<0.001). When plates were placed on the trolleys in controlled positions there was a tendency for the colonies to appear on the corners of the trolleys at the edge of the clean zone (NS). DISCUSSION: The study showed that in phase 1 colony counts comparable to the original Charnley studies were achieved. Colony counts of 0.03 colonies/plate/hour can be achieved in contemporary practice, with all team members using body exhausts.

Tour d'horizon des tests de diagnostic recommandés dans le Manuel des tests de diagnostic et des vaccins pour les animaux terrestres de l'Organisation mondiale de la santé animale.

To provide a standardised approach to the diagnosis of diseases and to facilitate health certification for trade, the World Organisation for Animal Health (OIE) standards, described in the Manual of Diagnostic Tests and Vaccines for Terrestrial Animals (Terrestrial Manual), include internationally agreed laboratory diagnostic techniques. This review examines the type of tests recommended in the disease-specific chapters of the Terrestrial Manual for the six most common purposes of diagnostic techniques, including certification for movement, confirmation of clinical cases and disease surveillance. The most frequently recommended tests for all six purposes are enzyme-linked immunosorbent assay and/or polymerase chain reaction, for which there are detailed validation guidelines in the OIE Terrestrial Manual. This is true for all species and no species-specific barriers to validation related to test type were identified. Classical techniques continue to be well represented in the Terrestrial Manual recommendations whereas novel technologies are slow to gain acceptance. These classical tests can present challenges for validation as there may be a dearth of international standard reagents and harmonised protocols.

Le normes de l'Organisation mondiale de la santé animale (OIE) décrites dans le Manuel des tests de diagnostic et des vaccins pour les animaux terrestres (Manuel terrestre) comprennent notamment des techniques de diagnostic de laboratoire acceptées au niveau international, destinées à fournir un cadre normalisé pour le diagnostic des maladies et à faciliter ainsi la certification sanitaire des échanges internationaux d'animaux et de produits d'origine animale. Les auteurs examinent les différentes catégories de tests recommandés dans les chapitres du Manuel terrestre dédiés à des maladies particulières pour les six principaux emplois assignés aux techniques diagnostiques, dont la certification sanitaire à des fins de déplacement, le diagnostic de confirmation des cas cliniques et la surveillance sanitaire. Les tests recommandés les plus courants pour chacun des six emplois sont l'épreuve immuno-enzymatique et/ou l'amplification en chaîne par polymérase, épreuves pour lesquelles le Manuel terrestre fournit des directives de validation détaillées. Ces directives s'appliquent à toutes les espèces, et aucun obstacle à la validation en lien avec une espèce particulière n'a été identifié pour l'une ou l'autre catégorie de tests. Les techniques classiques figurent toujours en bonne place dans les recommandations du Manuel terrestre, tandis que les technologies innovantes sont plus lentes à être acceptées. Les tests classiques peuvent poser des difficultés lors des essais de validation en raison du risque de pénurie de réactifs de référence internationaux et de l'absence de protocoles harmonisés.

Con objeto de instaurar métodos normalizados de diagnóstico de enfermedades y de facilitar la expedición de certificados sanitarios para el comercio, la Organización Mundial de Sanidad Animal (OIE), en las normas que establece en su Manual de las Pruebas de Diagnóstico y de las Vacunas para los Animales Terrestres (el Manual Terrestre), incluye técnicas de diagnóstico en laboratorio que suscitan consenso a nivel internacional. Los autores pasan revista a los tipos de prueba recomendados en los capítulos del Manual Terrestre relativos específicamente a una determinada enfermedad en relación con los seis propósitos con los que más comúnmente se utilizan las técnicas de diagnóstico, entre ellos la expedición de certificados para el desplazamiento de animales, la confirmación de casos clínicos y la vigilancia de enfermedades. Las pruebas recomendadas con más frecuencia para este conjunto de seis propósitos son el ensayo inmunoenzimático y/o la reacción en cadena de la polimerasa, para cuya validación se ofrecen detalladas indicaciones en el Manual Terrestre de la OIE. Esto se aplica a todas las especies, pues no se ha observado ninguna barrera a la validación asociada a una u otra especie que tenga que ver con el tipo de prueba. En las recomendaciones del Manual Terrestre siguen estando bien representadas las técnicas clásicas, a la par que las tecnologías novedosas van cobrando aceptación con lentitud. A veces la validación de estas pruebas clásicas presenta dificultades por la escasez de protocolos armonizados y de reactivos de referencia a nivel internacional.

Pseudomonas aeruginosa infection in augmented care: the molecular ecology and transmission dynamics in four large UK hospitals.

BACKGROUND: Pseudomonas aeruginosa is a common opportunistic pathogen and molecular typing in outbreaks has linked patient acquisition to contaminated hospital water systems. AIM: To elucidate the role of P. aeruginosa transmission rates in non-outbreak augmented care settings in the UK. METHODS: Over a 16-week period, all water outlets in augmented care units of four hospitals were sampled for P. aeruginosa and clinical isolates were collected. Outlet and clinical P. aeruginosa isolates underwent whole-genome sequencing (WGS), which with epidemiological data identified acquisition from water as definite (level 1), probable (level 2), possible (level 3), and no evidence (level 4). FINDINGS: Outlets were positive in each hospital on all three occasions: W (16%), X (2.5%), Y (0.9%) and Z (2%); and there were 51 persistently positive outlets in total. WGS identified likely transmission (at levels 1, 2 and 3) from outlets to patients in three hospitals for P. aeruginosa positive patients: W (63%), X (54.5%) and Z (26%). According to the criteria (intimate epidemiological link and no phylogenetic distance), approximately 5% of patients in the study 'definitely' acquired their P. aeruginosa from their water outlets in the intensive care unit. This study found extensive evidence of transmission from the outlet to the patients particularly in the newest hospital (W), which had the highest rate of positive outlets. CONCLUSIONS: The overall findings suggest that water outlets are the most likely source of P. aeruginosa nosocomial infections in some settings, and that widespread introduction of control measures would have a substantial impact on infections.

Effect of using fidaxomicin on recurrent Clostridium difficile infection.

Fidaxomicin is a macrocyclic antibiotic licensed for treating Clostridium difficile infection (CDI). In the UK, fidaxomicin is often reserved for severe CDI or recurrences. At Queen Elizabeth Hospital Birmingham, all courses of fidaxomicin during 2017/2018 were reviewed. Thirty-eight patients received fidaxomicin, of which 64% responded to treatment when fidaxomicin was given during the first episode of mild CDI. Conversely, all patients with recurrent CDI failed treatment with fidaxomicin. There were mixed results for the use of fidaxomicin for severe CDI, with only 42% of patients responding. These results suggest that fidaxomicin is best suited as a treatment for mild CDI during a patient's first episode.

Tap out: reducing waterborne Pseudomonas aeruginosa transmission in an intensive care unit.

BACKGROUND: Pseudomonas aeruginosa is a ubiquitous and important opportunistic pathogen in immunocompromised or critically ill patients. Nosocomial P. aeruginosa outbreaks have been associated with hospital water sources. AIM: To describe engineering interventions to minimize contamination of water outlets and the subsequent clinical impact. METHODS: New tap outlets were fitted at selected outlets across the intensive care unit (ICU). Laboratory testing demonstrated that, following artificial contamination with P. aeruginosa, these taps could be effectively decontaminated using a thermal washer-disinfector. Water samples were collected weekly from new outlets on the ICU over an eight-month period and tested for the enumeration of P. aeruginosa via membrane filtration. Surveillance of P. aeruginosa from clinical specimens was routinely undertaken. FINDINGS: Prior to the interventions, water sampling on ICU indicated that 30% of the outlets were positive for P. aeruginosa at any one time, and whole genome sequencing data suggested at least 30% transmission from water to patient. Since their installation, weekly sampling of the new tap outlets has been negative for P. aeruginosa, and the number of P. aeruginosa clinical isolates has fallen by 50%. CONCLUSION: Installation and maintenance of tap outlets free of P. aeruginosa can substantially reduce the number of P. aeruginosa clinical isolates in an ICU.

Unmasking leading to a healthcare worker Mycobacterium tuberculosis transmission.

BACKGROUND: Mycobacterium tuberculosis is a major health burden worldwide. The disease may present as an individual case, community outbreak, or more rarely as a nosocomial outbreak. Even in countries with a low prevalence such as the UK, tuberculosis (TB) presents a risk to healthcare workers (HCWs). AIM: To report an outbreak which manifested 12 months after a patient with pulmonary tuberculosis was admitted to Queen Elizabeth Hospital Birmingham. METHODS: We present the epidemiological and outbreak investigations; the role of whole genome sequencing (WGS) in identifying the outbreak and control measures to prevent further outbreaks. FINDINGS: Subsequent to a diagnosis of open TB in a patient, transmission was confirmed in one HCW who had active TB; HCWs with latent TB infection (LTBI) were also identified among seven HCW contacts of the index patient. Of note, all the LBTI patients had other risk factors for TB. Routine use of WGS identified the outbreak link between the index patient and the HCW with active TB disease, and informed our investigations. CONCLUSION: Exposure most likely occurred during an aerosol-generating procedure (AGP) which was done in accordance with national guidance at that time without using respiratory protection. Enhanced control measures were implemented following the outbreak.

Where to do water testing for Pseudomonas aeruginosa in a healthcare setting.

Pseudomonas aeruginosa is an important nosocomial pathogen widely colonizing hospital water supplies. The Department of Health (England) Health Technical Memorandum (HTM) 04-01 addresses the risk posed by recommending water-testing in augmented care areas including outpatient haemodialysis. We discuss how two teaching hospitals independently reviewed the risk to outpatient haemodialysis patients, drawing the same conclusion. The highest number of infection episodes with P. aeruginosa was observed in critical care followed by burns and haematology, with the lowest in haemodialysis. Based on these results, we suggest that water sampling should be undertaken in areas such as critical care, burns, and haematology, but not in outpatient haemodialysis.

Microbiological problems and biofilms associated with Mycobacterium chimaera in heater-cooler units used for cardiopulmonary bypass.

The role of heater-cooler units (HCUs) in the transmission of Mycobacterium chimaera during open heart surgery has been recognized since 2013. Subsequent investigations uncovered a remarkable global outbreak reflecting the wide distribution of implicated devices. HCUs are an essential component of cardiopulmonary bypass operations and their withdrawal would severely affect capacity for life-saving cardiac surgery. However, studies have demonstrated that many HCUs are contaminated with a wide range of micro-organisms, including M. chimaera and complex biofilms. Whole genome sequencing of M. chimaera isolates recovered from one manufacturer's HCUs, worldwide, has demonstrated a high level of genetic similarity, for which the most plausible hypothesis is a point source contamination of the devices. Dissemination of bioaerosols through breaches in the HCU water tanks is the most likely route of transmission and airborne bacteria have been shown to have reached the surgical field even with the use of ultraclean theatre ventilation. Controlling the microbiological quality of the water circulating in HCUs and reducing biofilm formation has been a major challenge for many hospitals. However, enhanced decontamination strategies have been recommended by manufacturers, and, although they are not always effective in eradicating M. chimaera from HCUs, UK hospitals have not reported any new cases of M. chimaera infection since implementing these mitigation strategies. Water safety groups in hospitals should be aware that water in medical devices such as HCUs may act as a vector in the transmission of potentially fatal water-borne infections.