Staphylococcus aureus bacteraemia in a UK tertiary referral centre: a 'transoesophageal echocardiogram for all' policy.

OBJECTIVES: Infective endocarditis (IE) is a feared complication in up to 38% of cases of Staphylococcus aureus bacteraemia (SAB). BSAC guidelines recommend echocardiography in all cases of SAB. The aim of this study was to determine the incidence of IE in SAB using transoesophageal echocardiography (TOE) as the first step in diagnostic imaging. This study also sought to identify clinical predictors that could improve stratification of those with and without IE. METHODS: A guideline was implemented that any SAB resulted in the microbiology department (i) recommending that the patient be referred for TOE and (ii) notifying the echocardiography department, resulting in streamlined listing of the patient for TOE. All cases of SAB were then assessed prospectively at University Hospitals Birmingham NHS Foundation Trust between September 2011 and October 2012. Previously identified risk factors for complicated S. aureus bacteraemia were recorded. RESULTS: There were 98 SAB episodes in total. TOE was performed in 58 (59%) with a further 22 episodes imaged by transthoracic echocardiography alone. IE was diagnosed overall in 13 (16%) cases investigated with echocardiography. No risk factor for IE other than presence of a cardiac device was detected in this group (P = 0.013). CONCLUSIONS: The rate of IE found in SAB is high when TOE is performed first line. There are no clear risk factors to improve yield or the type of echocardiography to be performed. Echocardiography should be performed in all cases and TOE should be considered where it is expected to influence management, as long as local resources allow.

pQEB1: a hospital outbreak plasmid lineage carrying bla KPC-2.

While conducting genomic surveillance of carbapenemase-producing Enterobacteriaceae (CPE) from patient colonisation and clinical infections at Birmingham's Queen Elizabeth Hospital (QE), we identified an N-type plasmid lineage, pQEB1, carrying several antibiotic resistance genes, including the carbapenemase gene bla KPC-2. The pQEB1 lineage is concerning due to its conferral of multidrug resistance, its host range and apparent transmissibility, and its potential for acquiring further resistance genes. Representatives of pQEB1 were found in three sequence types (STs) of Citrobacter freundii, two STs of Enterobacter cloacae, and three species of Klebsiella. Hosts of pQEB1 were isolated from 11 different patients who stayed in various wards throughout the hospital complex over a 13 month period from January 2023 to February 2024. At present, the only representatives of the pQEB1 lineage in GenBank were carried by an Enterobacter hormaechei isolated from a blood sample at the QE in 2016 and a Klebsiella pneumoniae isolated from a urine sample at University Hospitals Coventry and Warwickshire (UHCW) in May 2023. The UHCW patient had been treated at the QE. Long-read whole-genome sequencing was performed on Oxford Nanopore R10.4.1 flow cells, facilitating comparison of complete plasmid sequences. We identified structural variants of pQEB1 and defined the molecular events responsible for them. These have included IS26-mediated inversions and acquisitions of multiple insertion sequences and transposons, including carriers of mercury or arsenic resistance genes. We found that a particular inversion variant of pQEB1 was strongly associated with the QE Liver speciality after appearing in November 2023, but was found in different specialities and wards in January/February 2024. That variant has so far been seen in five different bacterial hosts from six patients, consistent with recent and ongoing inter-host and inter-patient transmission of pQEB1 in this hospital setting.

The value of the infection prevention and control nurse led MRSA ward round.

Meticillin-resistant S. aureus (MRSA) is prevalent in most parts of the world. The study took place at Queen Elizabeth Hospital Birmingham (QEHB) a UK tertiary referral hospital. At QEHB innovative nurse led daily ward rounds for patients that acquire hospital acquired MRSA during their hospital stay are undertaken. The aim is to optimise care delivered for these patients whilst at QEHB, thereby reducing the risk of infection in patients with healthcare-acquired MRSA. A segmented Poisson regression model suggests that the MRSA bacteraemia rate was affected where an 88.94% reduction (p = 0.0561) in bacteraemias was seen by the introduction of these ward rounds. We describe a nurse led MRSA ward round which was associated with a lower rate of MRSA bacteraemias.

Impact of a PCR point of care test for influenza A/B on an acute medical unit in a large UK teaching hospital: results of an observational, pre and post intervention study.

Background: Influenza viruses is a leading cause of acute respiratory infection, placing a significant burden on healthcare. To reduce hospital transmission, patients clinically suspected of having influenza are isolated and offered empirical antiviral treatment. Here we report the use of a point of care test (POCT) for influenza viruses in an acute medical unit (AMU) at Queen Elizabeth Hospital Birmingham for patients presenting with influenza-like illness. Methods: A PCR POCT was installed on AMU in Dec 17 - Mar 18 (period 2) and used to test any patient with influenza-like illness. We conducted an evaluation against influenza virus's data collected between Dec 16-Mar 17 (period 1) where no POCT was used. Four outcomes were measured: length of stay, oseltamivir utilisation, time to isolation and in-hospital cases of influenza viruses. Results: There were 51 confirmed influenza virus cases in period 1 vs 666 in period 2. During period 2, the length of stay of patients presenting with influenza-like illness (2.4 vs 7.9 days) and time to isolation from receipt of a positive result (0.09 vs 1.26 days) was significantly shorter. The time to initial receipt of antivirals for patients with influenza virus was significantly quicker in period 2 (0.59 vs 1.1 days) and the total number of influenza virus cases identified after 72 h of admission was significantly lower (9% vs 51%). Discussion: Following introduction of the POCT, there was an increase in appropriately targeted oseltamivir prescribing, shorter time to isolation, proportionally less post-72-h influenza virus cases and a reduction in length of stay of patients presenting with influenza-like illness. Conclusions: Routine use of POCTs for viruses should be introduced into diagnostic pathways for acute respiratory illness, especially at the front door of hospitals.

Waterborne Pseudomonas aeruginosa transmission in a hematology unit?

BACKGROUND: Pseudomonas aeruginosa is an important nosocomial pathogen that commonly colonizes hospital water supplies, including in taps and sinks. We report the transmission of P. aeruginosa from water to patients in a clinical hematology setting. METHODS: P. aeruginosa from water samples were compared to clinical isolates from hematology ward patients, via molecular typing (pulsed field gel electrophoresis). RESULTS: P. aeruginosa cultured from blood cultures from 3 patients was indistinguishable from water strains, by molecular typing. Based on infection control inspections, the transmission event was surmised to be due to cleaning of equipment, specifically an infusion therapy procedure tray used to transport intravenous drugs to patients, with water from an outlet colonized by P. aeruginosa. CONCLUSION: We show the importance of holistic factors, such as disposal of patient waste water, cleaning of tap outlets, and cleaning of medical equipment, in the transmission of P. aeruginosa, and demonstrate that the role of waterborne transmission of this organism in a hematology setting cannot be overlooked. We suggest that appropriate management of water, including both holistic and engineering interventions, is needed to stop transmission of P. aeruginosa from water to patients.

Wiping out MRSA: effect of introducing a universal disinfection wipe in a large UK teaching hospital.

Background: Contamination of the inanimate environment around patients constitutes an important reservoir of MRSA. Here we describe the effect of introducing a universal disinfection wipe in all wards on the rates of MRSA acquisitions and bacteraemias across a large UK teaching hospital. Methods: A segmented Poisson regression model was used to detect any significant changes in the monthly numbers per 100,000 bed days of MRSA acquisitions and bacteraemias from April 2013 - December 2017 across QEHB. Results: From April 2013 to April 2016, cleaning of ward areas and multi-use patient equipment by nursing staff consisted of a two-wipe system. Firstly, a detergent wipe was used, which was followed by a disinfection step using an alcohol wipe. In May 2016, QEHB discontinued the use of a two-wipe system for cleaning and changed to a one wipe system utilising a combined cleaning and disinfection wipe containing a quaternary ammonium compound. The segmented Poisson regression model demonstrated that the rate of MRSA acquisition/100,000 patient bed days was affected by the introduction of the new wiping regime (20.7 to 9.4 per 100,000 patient bed days; p <0.005). Discussion: Using a Poisson model we demonstrated that the average hospital acquisition rate of MRSA/100,000 patient bed days reduced by 6.3% per month after the introduction of the new universal wipe. Conclusion: We suggest that using a simple one wipe system for nurse cleaning is an effective strategy to reduce the spread and incidence of healthcare associated MRSA.

Can a toxin gene NAAT be used to predict toxin EIA and the severity of Clostridium difficile infection?

Background: Diagnosis of C. difficile infection (CDI) is controversial because of the many laboratory methods available and their lack of ability to distinguish between carriage, mild or severe disease. Here we describe whether a low C. difficile toxin B nucleic acid amplification test (NAAT) cycle threshold (CT) can predict toxin EIA, CDI severity and mortality. Methods: A three-stage algorithm was employed for CDI testing, comprising a screening test for glutamate dehydrogenase (GDH), followed by a NAAT, then a toxin enzyme immunoassay (EIA). All diarrhoeal samples positive for GDH and NAAT between 2012 and 2016 were analysed. The performance of the NAAT CT value as a classifier of toxin EIA outcome was analysed using a ROC curve; patient mortality was compared to CTs and toxin EIA via linear regression models. Results: A CT value ≤26 was associated with ≥72% toxin EIA positivity; applying a logistic regression model we demonstrated an association between low CT values and toxin EIA positivity. A CT value of ≤26 was significantly associated (p = 0.0262) with increased one month mortality, severe cases of CDI or failure of first line treatment. The ROC curve probabilities demonstrated a CT cut off value of 26.6. Discussions: Here we demonstrate that a CT ≤26 indicates more severe CDI and is associated with higher mortality. Samples with a low CT value are often toxin EIA positive, questioning the need for this additional EIA test. Conclusions: A CT ≤26 could be used to assess the potential for severity of CDI and guide patient treatment.

Decontamination of an Extracorporeal Membrane Oxygenator Contaminated With Mycobacterium chimaera.

Water samples taken from extracorporeal membrane oxygenator (ECMO) devices used at University Hospitals Birmingham yielded high total viable counts (TVCs) containing a variety of microorganisms, including M. chimaera. Disinfection resulted in the reduction of TVCs and eradication of Mycobacterium chimaera. Weekly disinfection and water sampling are required to manage the water quality in these devices. Infect Control Hosp Epidemiol 2017;38:1244-1246.

Engineering waterborne Pseudomonas aeruginosa out of a critical care unit.

OBJECTIVE: To describe engineering and holistic interventions on water outlets contaminated with Pseudomonas aeruginosa and the observed impact on clinical P. aeruginosa patient isolates in a large Intensive Care Unit (ICU). DESIGN: Descriptive study. SETTING: Queen Elizabeth Hospital Birmingham (QEHB), part of University Hospitals Birmingham (UHB) NHS Foundation Trust is a tertiary referral teaching hospital in Birmingham, UK and provides clinical services to nearly 1 million patients every year. METHODS: Breakpoint models were used to detect any significant changes in the cumulative yearly rates of clinical P. aeruginosa patient isolates from August 2013-December 2016 across QEHB. RESULTS: Water sampling undertaken on the ICU indicated 30% of the outlets were positive for P. aeruginosa at any one time. Molecular typing of patient and water isolates via Pulsed Field Gel Electrophoresis suggested there was a 30% transmission rate of P. aeruginosa from the water to patients on the ICU. From, February 2014, QEHB implemented engineering interventions, consisting of new tap outlets and PALL point-of-use filters; as well as holistic measures, from February 2016 including a revised tap cleaning method and appropriate disposal of patient waste water. Breakpoint models indicated the engineering and holistic interventions resulted in a significant (p<0.001) 50% reduction in the number of P. aeruginosa clinical patient isolates over a year. CONCLUSION: Here we demonstrate that the role of waterborne transmission of P. aeruginosa in an ICU cannot be overlooked. We suggest both holistic and environmental factors are important in reducing transmission.