Evaluation of the World Health Organization Global Invasive Bacterial Vaccine-Preventable Disease (IB-VPD) Surveillance Network's Laboratory External Quality Assessment Programme, 2014-2019.

Introduction. In 2009, the World Health Organization (WHO) established the Global Invasive Bacterial Vaccine Preventable Disease (IB-VPD) Surveillance Network (GISN) to monitor the global burden and aetiology of bacterial meningitis, pneumonia and sepsis caused by Haemophilus influenzae (Hi), Neisseria meningitidis (Nm) and Streptococcus pneumoniae (Sp).Hypothesis/Gap Statement. The GISN established an external quality assessment (EQA) programme for the characterization of Hi, Nm and Sp by culture and diagnostic PCR.Aim. To assess the performance of sentinel site laboratories (SSLs), national laboratories (NLs) and regional reference laboratories (RRLs) between 2014 and 2019 in the EQA programme.Methodology. Test samples consisted of bacterial smears for Gram-staining, viable isolates for identification and serotyping or serogrouping (ST/SG), plus simulated cerebrospinal fluid (CSF) samples for species detection and ST/SG by PCR. SSLs and NLs were only required to analyse the slides for Gram staining and identify the species of the live isolates. RRLs, and any SLs and NLs that had the additional laboratory capacity, were also required to ST/SG the viable isolates and analyse the simulated CSF samples.Results. Across the period, 69-112 SS/NL labs and eight or nine RRLs participated in the EQA exercise. Most participants correctly identified Nm and Sp in Gram-stained smears but were less successful with Hi and other species. SSLs/NLs identified the Hi, Nm and Sp cultures well and also submitted up to 56 % of Hi, 62 % of Nm and 33 % of Sp optional ST/SG results each year. There was an increasing trend in the proportion of correct results submitted over the 6 years for Nm and Sp. Some SSLs/NLs also performed the optional detection and ST/SG of the three organisms by PCR in simulated CSF from 2015 onwards; 89-100 % of the CSF samples were correctly identified and 76-93 % of Hi-, 90-100 % of Nm- and 75-100 % of Sp-positive samples were also correctly ST/SG across the distributions. The RRLs performed all parts of the EQA to a very high standard, with very few errors across all aspects of the EQA.Conclusion. The EQA has been an important tool in maintaining high standards of laboratory testing and building of laboratory capacity in the GISN.

Screening methods for meticillin-resistant Staphylococcus aureus.

The UK National External Quality Assessment Service (UK NEQAS) distributes clinically relevant and educational specimens for external quality assessment (EQA). The aim of this report was to assess the suitability of using a freeze-dried specimen format for the EQA of conventional and rapid methods and to review the methods used by participants to screen for meticillin-resistant Staphylococcus aureus (MRSA). Of the 714 laboratories that returned a result, 678 reported the presence of MRSA, and results showed a mean of 73 c.f.u. per 25 µl and a median of 50 c.f.u. per 25 µl confirming that the specimen was homogeneous. Four different approaches to MRSA screening were used routinely, including: (i) liquid culture; (ii) direct plating onto conventional media; (iii) direct plating onto chromogenic media; and (iv) rapid methods. A wide variety of methods were used within each of these four categories to screen for MRSA, and many laboratories reported using more than one method. Attempts should be made to determine the most appropriate approach to MRSA screening and to standardize the protocols across the UK.

External quality assessment for molecular detection of human papillomaviruses.

BACKGROUND: The United Kingdom National External Quality Assessment Service (UK NEQAS) distributes clinically relevant and educational specimens for external quality assessment (EQA). OBJECTIVES: The aim of this report was to assess the suitability of using liquid based cytology (LBC) samples for the EQA of molecular methods and to review the methods used by participants to detect the presence of high risk (HR) human papillomavirus (HPV) genotypes. STUDY DESIGN: Three pilot distributions were dispatched between January 2008 and January 2009 with each distribution consisting of four different specimens. RESULTS: Performance was good with over 90% of participants reporting correctly on the presence or absence of high risk genotypes in all but one specimen, specimen 9006 (82.1%). Specimen 9006 was a pooled specimen, negative for HR genotypes but containing low risk (LR) genotypes 61, 70 and 81. The most commonly used assay for the detection of the presence of HR HPV was the Digene Hybrid Capture II assay. The in-house PCR assays were most commonly associated with incorrect results, and the use of these assays decreased during the 13 month pilot study. CONCLUSIONS: The UK NEQAS molecular detection of HPV scheme provides a standardised, homogeneous and characterised clinical specimen, however this study has shown that genotyping results reported by participants were still varied. Inclusion of available HPV standards will help to standardise assays. Robust EQA of HPV molecular screening programmes will be essential for monitoring the impact of the HPV vaccine.

Wide geographic spread of diverse acquired AmpC beta-lactamases among Escherichia coli and Klebsiella spp. in the UK and Ireland.

OBJECTIVES: To determine the distribution of acquired AmpC beta-lactamases in 173 isolates of Escherichia coli and Klebsiella spp. submitted to the UK's national reference laboratory for antibiotic resistance. METHODS: MICs were determined and interpreted according to BSAC guidelines. Candidate isolates were those resistant to cefotaxime and/or ceftazidime, irrespective of addition of clavulanic acid. Genes encoding six phylogenetic groups of acquired AmpC enzymes were sought by PCR. Selected isolates were compared by pulsed-field gel electrophoresis (PFGE), and one bla(AmpC) amplicon was sequenced. RESULTS: Genes encoding acquired AmpC enzymes were detected in 67 (49%) candidate E. coli and 21 (55%) Klebsiella spp. Sixty isolates produced CIT-type enzymes, 14 had ACC types, 11 had FOX types and 3 had DHA enzymes. The low-level cephalosporin resistance of the remaining isolates (n = 85; 49%) was inferred to result from reduced permeability or, in E. coli, from hyperexpression of chromosomal ampC. Twenty-four E. coli isolates from one hospital produced a CIT-type enzyme, with 20 of these additionally producing a group 1 CTX-M extended-spectrum beta-lactamase. PFGE indicated that these isolates belonged to UK epidemic strain A, which normally produces CTX-M-15, but no acquired AmpC. Sequencing a representative bla(AmpC) amplicon indicated that in one centre this strain had acquired a novel CMY-2 variant, designated CMY-23. CONCLUSIONS: Diverse acquired AmpC enzymes occur in E. coli and Klebsiella spp. isolates in the UK and Ireland, with CIT types the most common. Producers are geographically scattered, but with some local outbreaks. Acquisition of a CMY-2-like enzyme by E. coli epidemic strain A suggests that these enzymes may be poised to become an important public health issue.

Emergence of Enterobacteriaceae isolates producing CTX-M extended-spectrum beta-lactamase in Austria.

Among 149 extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae isolates collected from patients in southeast Austria from 1998 to 2004, 38 Escherichia coli isolates and 11 Klebsiella spp. were CTX-M producers. The proportion of CTX-M-producers among all ESBL producers rose from 0% in 1998 to 58% in 2004. In general, CTX-M-producers had heterogeneous pulsed-field gel electrophoresis patterns, but one E. coli isolate was identical to a United Kingdom epidemic CTX-M-15-producing strain, although no epidemiological link with the United Kingdom was apparent.