Enhanced surveillance of carbapenemase-producing Gram-negative bacteria to support national and international prevention and control efforts

Epidemiology of carbapenemase-producing Enterobacterales in England, May 2015-March 2019: national enhanced surveillance findings and approach

Background

In response to increasing numbers of carbapenemase-producing Enterobacterales (CPE) in England, Public Health England (PHE) launched an electronic reporting system (ERS) for the enhanced surveillance of carbapenemase-producing Gram-negative bacteria. Our study aimed to describe system engagement and the epidemiology of CPE in England.

Methods

Engagement with the ERS was assessed by calculating the proportion of referrals submitted this system. ERS data were extracted and cases defined as patients with CPE isolated from a screening or clinical specimen in England between 1^st May 2015 to 31^st March 2019. Descriptive summary statistics for each variable were prepared.

Results

The ERS processed 12,656 suspected CPE reports. Uptake of the ERS by local microbiology laboratories varied, with approximately 70% of referrals made via the ERS by April 2016; this steadily decreased after March 2018. Six-thousand eight-hundred and fifty-seven cases were included in the analysis. Most cases were from colonised patients (80.6%) rather than infected, and the majority were inpatients in acute hospital settings (87.3%). Carbapenemases were most frequently detected in Klebsiella pneumoniae (39.1%) and Escherichia coli (30.3%). The most frequently identified carbapenemase families were OXA-48-like (45.1%) and KPC (26.4%). Enhanced data variables were poorly completed.

Conclusions

The ERS has provided some insight into the epidemiology of CPE in England. An increasing number of routine diagnostic laboratories have introduced methods to routinely identify acquired carbapenemases and PHE has modified its approach to ensure robust surveillance, which is an essential aspect of an effective response to prevent and control the spread of CPE.

An evaluation of the electronic reporting system for the enhanced surveillance of carbapenemase-producing Gram-negative bacteria in England

BACKGROUND

An electronic reporting system (ERS) for the enhanced surveillance of carbapenemase-producing Gram-negative bacteria (CPGNB) was launched by Public Health England in May 2015.

AIM

This evaluation aimed to assess uptake, timeliness and completeness of data provided and explore potential barriers and facilitators to adopting the system.

METHODS

The evaluation comprised a retrospective analysis of surveillance data and semi-structured interviews with ERS users.

FINDINGS

The proportion of organisms referred for investigation of carbapenem resistance via ERS increased over the first 12 months post-implementation from 35% to 73%; uptake varied widely across regions of England. Completeness of enhanced data fields was poor in 78% of submitted isolates. The median number of days to report confirmatory test results via ERS was 1 day for the regional service and nine days for the national reference laboratory, which additionally conducts phenotypic testing to confirm carbapenemase negativity. Hindrances to ERS utility included: a lack of designated, ongoing resource for system maintenance, technical support and development; uncertainty about how and when to use ERS and workload. Incomplete data prevented gaining a better understanding of important risk factors and transmission routes of CPGNB in England.

CONCLUSION

The ERS is the only surveillance system in England with the potential to gather intelligence on important risk factors for CPGNB to inform public health measures to control their spread. Although the ERS captures more information on CPGNB than other surveillance systems, timeliness and completeness of the enhanced data require substantial improvements in order to deliver the desired health benefits.

Role of the Clinical Microbiology Laboratory in Antimicrobial Stewardship

For adequate antimicrobial stewardship, microbiology needs to move from the laboratory to become physically and verbally amenable to the caregivers of an institution. Herein, we describe the contributions of our microbiology department to the antimicrobial stewardship program of a large teaching hospital as 10 main points ranging from the selection of patients deemed likely to benefit from a fast track approach, to their clinical samples, or the rapid reporting of results via a microbiology hotline, to rapid searches for pathogens and susceptibility testing. These points should serve as guidelines for similar programs designed to decrease the unnecessary use of antimicrobials.

Detection of different classes of carbapenemases: Adaptation and assessment of a phenotypic method applied to Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii, and proposal of a new algorithm

A new phenotypic method for detecting carbapenemases has been adapted (assembling of two MAST® kits, including one that contains faropenem to which a temocillin disk has been added) then assessed using 101 bacterial strains (Enterobacteriaceae with assays on Pseudomonas aeruginosa and Acinetobacter baumannii) including 62 which produce genetically identified carbapenemases. Concerning Carbapenemase-Producing Enterobacteriaceae (CPE), there is 100% sensitivity for Klebsiella pneumoniae carbapenemase (KPC, Ambler class A) and OXA-48 (Ambler class D), and 91% for metallo-beta-lactamase (MBL, Ambler class B), with a 97% sensitivity for all carbapenemases, with a specificity of 100%. The test is also efficient for detecting Pseudomonas aeruginosa carbapenemases (sensitivity between 82 and 100% and 100% specificity). The major innovation is the combined use of faropenem and temocillin for reliable detection (excellent performance with 100% sensitivity and specificity) of OXA-48. This study has led to the development of a new algorithm to detect the different classes of carbapenemases, for first-line diagnosis, by combining this modified MAST® test with immunochromatographic methods and molecular biology techniques.