Specialist Antimicrobial Chemotherapy Unit (SACU)

Targeted Surveillance (SACU 2021)

All Wales 3GC targeted surveillance study

Carbapenem resistance in Gram-negative bacteria is an increasing problem across Wales and the World, resulting in treatment failures and contributing a significant risk to the patient. Third generation cephalosporin (3GC) resistance in Gram-negative bacteria drives carbapenem use and may contribute to increasing levels of resistance.

It is therefore important to determine the levels of 3GC resistance in Gram-negative bacteria; every 5 years SACU will collect a cross section of 3GC resistant Enterobactericeae strains isolated in Welsh laboratories and investigate the mechanisms of resistance.

In 2008 and 2014 SACU collected approximately 1/6th of all 3GC resistant Enterobacteriaceae across Wales. Details of the 2008 and 2014 collection can be seen in the reports below. We are currently collecting strains isolated during 2020 to 2021. Next collection is likely to be 2025 to 2026.

Report targeted surveillance for 3rd generation cephalosporin resistance in Wales:

3rd Generation Cephalosporin Resistance in Wales 2008 (Sept 2010)

3rd Generation Cephalosporin Resistance in Wales 2014 (Oct 2020)

2020 surveillance:

We would like to continue our surveillance of 3rd generation cephalosporin resistance in Wales by asking all laboratories to submit the following isolates to SACU:

Hospital Location	No. Requested	Hospital E.coli	Hospital Coliform	GP E.coli	GP Coliform
Bronglais Hospital, Aberystwyth	32	6	4	17	5
Royal Gwent, Newport (incl. Royal Glamorgan)	196	39	62	54	41
UHW, Cardiff	169	48	29	68	24
Singleton, Swansea	226	25	90	27	84
WWGH, Carmarthen	129	26	30	36	37
Ysbyty Glan Clwyd, Rhyl (incl Maelor & Bangor)	259	62	45	102	50
Total	1011	206	260	304	241

Clinical Trials

SACU provides central laboratories services and principal investigator roles to a number of clinical trials, both in UK and in Europe.

We collaborate with many institutions on clinical trials, which mainly focus on reducing antimicrobial prescribing or novel interventions to reduce prescribing.

We provide processing of primary samples, susceptibility testing, detection and characterisation of antimicrobial resistance mechanisms, data analysis and report writing.

The following clinical trials are currently being undertaken within SACU:

MenB Study

This study is in collaboration with Oxford University Vaccine Group and aims to evaluate the effect of immunisation against group B meningococcus on meningococcal carriage.

SACU and Health Protection within Public Health Wales collaborate with other centres around the UK by collecting and processing throat swabs from young adults.

SACU is processing and confirming presence of Neisseria meningitidis, the bacterium target of the menB vaccine and responsible for meningitis.

The study covers the years 2018-2021, with two collection periods in spring and autumn.
For more information: https://beontheteam.web.ox.ac.uk/

Review of Mupirocin resistance in S. aureus

 A study which will review the amount of mupirocin resistance in S. aureus from 200 patients across South East Wales following a change in practice for haemodialysis.

Commercial and Research Studies 

SACU has more than 15 years expertise in susceptibility testing using a variety of methodologies and has worked with several commercial partners to develop and validate both novel antimicrobials and a variety of susceptibility tests.  Evaluation services provides by SACU varies from basic to bespoke.

SACU holds a large collection of clinically relevant Gram-negative and Gram-positive isolates (e.g. Enterobacteriales, Pseudomonas, Acinetobacter, Stenotrophomonas, Burkholderia, Staphylococci, Enterococci, Streptococci).

The collection includes isolates recovered from cohorts of patients and clinical scenarios (e.g. cystic fibrosis, COPD, UTI etc) and various resistance mechanisms (e.g. ESBL, ampC, carbapenemase, hGISA, VRE, etc…).

Antimicrobial susceptibility testing by broth microdilution (BMD), agar dilution, gradient strips and standardised EUCAST disc diffusion is offered. Expertise in more research based methods including synergy testing using time kill curves and chequerboard techniques as well as disinfectant testing using suspension tests is also available. 

Resistance mechanism determination can be performed using inhibitor based phenotypic methods as well as by genotypic analysis by standard and real time  Polymerase Chain Reaction (PCR). Whole Genome Sequence (WGS) analysis is currently in development for use in the near future.

SACU can evaluate the following:

1. Gradient strips and discs for new agents. 
2. Novel susceptibility testing methods.
   • New techniques.
   • Rapid techniques.
   • Commercial susceptibility testing instruments.
3. Novel antimicrobials.
   • Basic antibacterial evaluation of unknown compounds.
   • Phase I trials.
4. Resistance mechanism determination.
   • Phenotypic methods.
   • Genotypic methods
   • Commercial instruments.

 Please contact Dr Mandy Wootton by email or phone for more details:

E-mail: [email protected]

Tel: 029 20 743 610 

BSAC and EUCAST studies (2021)

SACU is the British Society for Antimicrobial Chemotherapy (BSAC) Susceptibility Testing Laboratory for the UK, providing advice on all aspects of EUCAST methods & guidelines. The unit also provides advice on anomalous quality testing issues and verification when implementing EUCAST disc diffusion methods.

SACU collaborates with the EUCAST Development Laboratory on a number of studies to develop disc diffusion guidelines for new agents and bacteria. Recent work has focussed on reading guidance on Nocardia reference testing plus Stenotrophomonas and Burkholderia susceptibility testing.

The unit is currently working with other reference laboratories on the development of disc diffusion methods for Neisseria species and anaerobic bacteria with a EUCAST subcommittee being formed for the latter. The unit has also recently provided data for extending the nitrofurantoin and mecillinam clinical breakpoints to supplemental Enterobacteriales other than those stated in the EUCAST breakpoint table.

http://bsac.org.uk/ & http://eucast.org/

Other BSAC collaborations

SACU recently worked alongside the Institute of Biomedical Science (IBMS) to review the Specialist portfolio in medical microbiology. The antimicrobial susceptibility testing section (7.9) has been updated to reflect current practices and methods. The standardised EUCAST disc test features highly with updated sections on currently relevant resistance mechanisms.

SACU also works with the UK Standards in Microbiology Investigation (SMI) group to discuss the antimicrobial agents for testing within diagnostic laboratories.

Training and Courses

As part of the BSAC Susceptibility testing laboratory for the UK, SACU runs two 3-day Residential Courses and two 1-day Userday conferences per year.

BSAC Susceptibility testing Residential workshops (3 days)

The BSAC workshop is a 3 day intensive course (including laboratory training) which aims to provide:

• Knowledge of EUCAST disc diffusion susceptibility testing methods
• An overview of other susceptibility testing methods
• An understanding of how to test difficult organisms
• An overview of relevant resistance mechanisms
• Knowledge of how to solve susceptibility testing problems
• Knowledge to improve local susceptibility reporting
• Information on how to detect common antimicrobial resistance mechanisms and an overview of new technology in microbiology

 Place: The workshops are held at the University Hospital of Wales, Cardiff.

 Time: They take place every March/April (the week before Easter) and August (the week before August bank holiday).

Refer to the BSAC website for further details and registration.

BSAC User day 1-day conferences

SACU runs two 1-day conferences each year at different locations throughout the UK. The conference aims to update delegates on new resistances, problematic susceptibility testing issues, updates in testing methods and infections difficult to treat. 

It is also an opportunity to discuss susceptibility testing issues affecting laboratories around the UK.

Place: The User day conferences are held at various locations around the UK

Time:  User days are usually held in June and October of every year.

Refer to the BSAC website for further details and registration.

Useful Links

BSAC Standing Committee on Susceptibility Testing

BSAC Resistance Surveillance Project

European Committee on Antimicrobial Susceptibility Testing (EUCAST)

EUCAST MIC / Zone diameter distributions & ECOFFs

The Antibiotic Resistance & Health Care Associated Infection Reference Laboratory (AMRHAI)

European Surveillance of Antimicrobial Consumption (ESAC)

European Antimicrobial Resistance Surveillance System (EARSS)

Massive Online Open Source Course of Antimicrobial Stewardship (BSAC)

Outpatient Parenteral Antimicrobial Therapy

WHO Collaborating Centre for Drugs Statistics Methodology

Antimicrobial Resistance & GENomic Typing project (ARGENT)

Antimicrobial resistance has been identified as a key public health concern, with infections caused by Multi-Drug Resistant Organisms (MDRO) posing a significant threat to patient outcome and to the management of healthcare settings. Carbapenem resistant Gram-negative organisms are of particular concern as they are increasingly associated with hospital outbreaks.

These outbreaks can be caused by direct spread of closely related organisms or can involve sharing of several resistance genes, carried by mobile genetic element, between unrelated bacteria; as a result, sensitive bacteria can acquire resistance to many different antibiotics by the simple acquisition of a mobile element.

During outbreaks it is crucial to rapidly gather information about relatedness of different isolates and the mobile element they carry. Newer sequencing technologies allow now to better decipher means of transmission and therefore guiding strategies to prevent further spread of infections. In addition, complete genome sequences of outbreak organisms can reveal a more detailed picture about the pool of resistance determinants than existing methods.

The ARGENT project aims to develop a genomics based typing service to support outbreak investigation in Welsh healthcare settings. The first few years focussed on carbapenem- resistant Acinetobacter baumannii, Pseudomonas aeruginosa and vancomycin-resistant Enterococci.

Although the service is not yet fully operational, it has already supported recent outbreak investigations across Wales. As part of the project, representative bacterial isolates from blood cultures (except coagulase-negative Staphylococci and anaerobes) are now being sequenced in order to identify strains (regardless of their antibiotic resistance profile) that maybe spreading across different healthcare settings. All laboratories across Wales are encouraged to submit blood culture isolates for one year using the form.