External quality assurance scheme for Haemophilus influenzae 2011

External quality assurance scheme for Haemophilus influenzae
TECHNICAL REPORT
Conclusions
A certain degree of heterogeneity exists in the level of characterisation of strains of Haemophilus influenzae among
EU countries. This emphasises the need for consensus and agreement in methods for characterising and accurately
defining this organism. This is outside the remit of the EQA exercise and should be addressed by the IBD-Labnet
together with the ECDC. Some countries still require some capacity building in this area.
There were a number of problems with the design of the web reporting system. For example, it did not include a
‘not applicable’ category for the tests. We will endeavour to improve the design of the web reporting scheme in
future distributions.
The EQA exercise has again demonstrated the value of PCR-based genotyping methods in providing identification
of Haemophilus spp. and a serotype/genotype for strains that give inconclusive results on slide agglutination.
Ideally a genotyping method should be used for all H. influenzae isolates in order to confidently identify Hib and
capsule deficient Hib - strains. This is of particular importance where routine Hib immunisation is used, since it is
essential to be able to accurately identify Hib vaccine failures. It is of note that the Hib isolate included in the EQA
was identified by the majority of participating laboratories. In addition, molecular based capsular typing can act as
a quality control measure to monitor the accuracy of the results of conventional serotyping.
The results of antimicrobial susceptibility testing again proved difficult to interpret due to the use of different
methods and breakpoints. It is recommended that all European laboratories adopt the EUCAST methods and
clinical breakpoints of antimicrobial susceptibility testing which should facilitate better comparison of the results
from different laboratories (http://www.EUCAST.org) and comply with the 2012 case definitions for EU surveillance
of antimicrobial resistance.
For the first time, two simulated clinical samples were included in the EQA panel to assess non-culture detection
methods. The results were very encouraging, but a larger number of this type of sample will be required in future
distributions to assess participants’ proficiency more rigorously.
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