An evaluation of a toolkit for the early detection, management, and control of carbapenemase-producing Enterobacteriaceae: a survey of acute hospital trusts in England

Model-based evaluation of admission screening strategies for the detection and control of carbapenemase-producing Enterobacterales in the English hospital setting

BACKGROUND

Globally, detections of carbapenemase-producing Enterobacterales (CPE) colonisations and infections are increasing. The spread of these highly resistant bacteria poses a serious threat to public health. However, understanding of CPE transmission and evidence on effectiveness of control measures is severely lacking. This paper provides evidence to inform effective admission screening protocols, which could be important in controlling nosocomial CPE transmission.

METHODS

CPE transmission within an English hospital setting was simulated with a data-driven individual-based mathematical model. This model was used to evaluate the ability of the 2016 England CPE screening recommendations, and of potential alternative protocols, to identify patients with CPE-colonisation on admission (including those colonised during previous stays or from elsewhere). The model included nosocomial transmission from colonised and infected patients, as well as environmental contamination. Model parameters were estimated using primary data where possible, including estimation of transmission using detailed epidemiological data within a Bayesian framework. Separate models were parameterised to represent hospitals in English areas with low and high CPE risk (based on prevalence).

RESULTS

The proportion of truly colonised admissions which met the 2016 screening criteria was 43% in low-prevalence and 54% in high-prevalence areas respectively. Selection of CPE carriers for screening was improved in low-prevalence areas by adding readmission as a screening criterion, which doubled how many colonised admissions were selected. A minority of CPE carriers were confirmed as CPE positive during their hospital stay (10 and 14% in low- and high-prevalence areas); switching to a faster screening test pathway with a single-swab test (rather than three swab regimen) increased the overall positive predictive value with negligible reduction in negative predictive value.

CONCLUSIONS

Using a novel within-hospital CPE transmission model, this study assesses CPE admission screening protocols, across the range of CPE prevalence observed in England. It identifies protocol changes-adding readmissions to screening criteria and a single-swab test pathway-which could detect similar numbers of CPE carriers (or twice as many in low CPE prevalence areas), but faster, and hence with lower demand on pre-emptive infection-control resources. Study findings can inform interventions to control this emerging threat, although further work is required to understand within-hospital transmission sources.

Detecting carbapenemase-producing Enterobacterales (CPE): an evaluation of an enhanced CPE infection control and screening programme in acute care

Objectives

The transmission of carbapenemase-producing Enterobacterales (CPE) poses an increasing healthcare challenge. A range of infection prevention activities, including screening and contact precautions, are recommended by international and national guidelines. We evaluated the introduction of an enhanced screening programme in a multisite London hospital group.

Methods

In June 2015, an enhanced CPE policy was launched in response to a local rise in CPE detection. This increased infection prevention measures beyond the national recommendations, with enhanced admission screening, contact tracing and environmental disinfection, improved laboratory protocols and staff/patient education. We report the CPE incidence and trends of CPE in screening and clinical cultures and the adoption of enhanced CPE screening. All non-duplicate CPE isolates identified between April 2014 and March 2018 were included.

Results

The number of CPE screens increased progressively, from 4530 in July 2015 to 10 589 in March 2018. CPE detection increased from 18 patients in July 2015 (1.0 per 1000 admissions) to 50 patients in March 2018 (2.7 per 1000 admissions). The proportion of CPE-positive screening cultures remained at approximately 0.4% throughout, suggesting that whilst the CPE carriage rate was unchanged, carrier identification increased. Also, 123 patients were identified through positive CPE clinical cultures over the study period; there was no significant change in the rate of CPE from clinical cultures per 1000 admissions (P = 0.07).

Conclusions

Our findings suggest that whilst the enhanced screening programme identified a previously undetected reservoir of CPE colonization in our patient population, the rate of detection of CPE in clinical cultures did not increase.

Epidemiology and control measures of an OXA-48-producing Enterobacteriaceae hospital outbreak

Carbapenemase-producing Enterobacteriaceae (CPE) are a significant challenge to healthcare and infection prevention and control teams. In the UK, OXA-48-like carbapenemases are frequently reported. We describe an outbreak of OXA-48-like producing Enterobacteriaceae and the control measures that proved effective in containing further spread.

Aim

To describe epidemiologic and laboratory features of outbreak and highlight key control interventions.

Findings

Following the introduction of an increased sensitivity CPE screening protocol, OXA-48-like CPE were identified in screening and clinical samples from 96 patients across five hospital wards between November 2017 and July 2018. Klebsiella pneumoniae and Enterobacter cloacae were the most frequently isolated organisms, although a range of OXA-48-like positive organisms were identified. The outbreak was contained utilising certain key interventions, including the modification of laboratory screening processes, engagement of hospital senior management, clear and frequent communication and a strong ‘ward presence’ by the infection prevention and control team (IPCT).

Conclusion

Our report describes how a change in laboratory CPE screening process unmasked a CPE outbreak. The range of bacterial species harbouring the OXA-48-like mechanism suggested plasmid-mediated transfer of resistance. The timely implementation of interventions using a clinical, ‘ward-based’ approach to infection prevention and control highlights the importance of behavioural change in infection control interventions and enabled the termination of a large outbreak without recourse to environmental sampling, major remedial construction work or extensive molecular strain or plasmid typing.

The Rapid Carbapenemase Detection Method (rCDM) for Rapid and Accurate Detection of Carbapenemase-Producing Enterobacteriaceae and Pseudomonas aeruginosa

This study aimed to design a new method for rapid and accurate detection of carbapenemase phenotypes based on the simplified carbapenem inactivation method (sCIM). We evaluated the sensitivity and specificity of the method, called the rapid carbapenemase detection method (rCDM), for the detection of carbapenemase-producing Enterobacteriaceae and Pseudomonas aeruginosa. A total of 257 Enterobacteriaceae, 236 P. aeruginosa, and 20 Acinetobacter baumannii isolates were tested. Phenotypic evaluations were performed using rCDM, sCIM, and mCIM. For Enterobacteriaceae, the sensitivity of rCDM was 100% and the specificity was 99.6%. For P. aeruginosa, the sensitivity of rCDM was 97.4% and the specificity was 100%. Carbapenemase-producing A. baumannii were not detected by rCDM. The concordance rate of rCDM and sCIM for Enterobacteriaceae and P. aeruginosa was 99.8%, with the exception of one P. aeruginosa isolate that expressed the bla_VIM−4 gene. The concordance rate of rCDM and mCIM for Enterobacteriaceae and P. aeruginosa was 100%. rCDM can be used to accurately detect carbapenemase-producing Enterobacteriaceae and P. aeruginosa in 5–6 h and is suitable for routine use in most clinical microbiology laboratories.

Implementing a toolkit for the prevention, management and control of carbapenemase-producing Enterobacteriaceae in English acute hospitals trusts: a qualitative evaluation

BACKGROUND

Antimicrobial resistance is an increasing problem in hospitals world-wide. Following other countries, English hospitals experienced outbreaks of carbapenemase-producing Enterobacteriaceae (CPE), a bacterial infection commonly resistant to last resort antibiotics. One way to improve CPE prevention, management and control is the production of guidelines, such as the CPE toolkit published by Public Health England in December 2013. The aim of this research was to investigate the implementation of the CPE toolkit and to identify barriers and facilitators to inform future policies.

METHODS

Acute hospital trusts (N = 12) were purposively sampled based on their self-assessed CPE colonisation rates and time point of introducing local CPE action plans. Following maximum variation sampling, 44 interviews with hospital staff were conducted between April and August 2017 using a semi-structured topic guide based on the Capability, Opportunity, Motivation and Behaviour Model and the Theoretical Domains Framework, covering areas of influences on behaviour. Interviews were audio-recorded, transcribed verbatim and analysed using thematic analysis.

RESULTS

The national CPE toolkit was widely disseminated within infection prevention and control teams (IPCT), but awareness was rare among other hospital staff. Local plans, developed by IPCTs referring to the CPE toolkit while considering local circumstances, were in place in all hospitals. Implementation barriers included: shortage of isolation facilities for CPE patients, time pressures, and competing demands. Facilitators were within hospital and across-hospital collaborations and knowledge sharing, availability of dedicated IPCTs, leadership support and prioritisation of CPE as an important concern. Participants using the CPE toolkit had mixed views, appreciating its readability and clarity about patient management, but voicing concerns about the lack of transparency on the level of evidence and the practicality of implementation. They recommended regular updates, additional clarifications, tailored information and implementation guidance.

CONCLUSIONS

There were problems with the awareness and implementation of the CPE toolkit and frontline staff saw room for improvement, identifying implementation barriers and facilitators. An updated CPE toolkit version should provide comprehensive and instructive guidance on evidence-based CPE prevention, management and control procedures and their implementation in a modular format with sections tailored to hospitals' CPE status and to different staff groups.

Survey of screening methods, rates and policies for the detection of carbapenemase-producing Enterobacteriaceae in English hospitals

Multi-drug-resistant Gram-negative bacteria are of major clinical concern. The increasing prevalence of carbapenemase-producing Enterobacteriaceae (CPE), resistant to all beta-lactams including carbapenems and able to colonize the large intestine, represents a key threat. Rapid, accurate detection of intestinal CPE colonization is critical to minimize transmission, and hence reduce costly, difficult-to-treat CPE infections. There is currently no 'gold standard' CPE detection method. A survey of diagnostic laboratories in England found considerable heterogeneity in diagnostic CPE testing methods and procedures.