S1 De voorjaarsbijeenkomst van de Nederlandse ... - NVMM

were determined following ISO guidelines (ISO 20776-1)
and instructions of the MICE manufacturer, respectively.
For the MICE, an inoculum of 0.5 McFarland was streaked
on a Mueller-Hinton agar plate. The MICE strips were put
on the plate and incubated for 16-20h. The MIC values
were read following instruction by two independent lab
technicians. The following MICE strips were evaluated:
gentamicin 256-0.016 mg/L (Ge 256), gentamicin
1024-0.064 mg/L GE024), amoxicillin 256-0.016 mg/L
(AM), cefotaxime 32-0.002 mg/L (Cef32), cefotaxime
256-0.016 mg/L (Cef256), levofloxacin 32-0.002 mg/L (LE),
imipenem 32-0.002 mg/L (IM), ciprofloxacin 32-0.002
mg/L (CI), amoxicillin/clavulanic acid 256 – 0.016 mg/L
(AC). For the interpretation of the MIC and MICE the
EUCAST breakpoints were used. Discrepancy analysis was
performed following the ISO guideline.
Results: The isolates collected belonged to the following
species Citrobacter species (n=15), Enterobacter spp (n=35),
Escherichia coli (n=80), Hafnia alveii (n=1), Klebsiella spp
(n=84), Morganella morganii (n=10), Pantoea agglomerans
(n=1), Proteus species (n=67), Providencia rettgeri (n=1),
Serratia marcescens (n=6). 63% of the strains were
susceptible for the different antimicrobial agents. The
category agreement after discrepancy analysis was:
GE256 99%, GE1024 99%, AM 96%, cef32 99%, cef256
99%, LE 98%, IM 99%, CI 98%
and AC 89% (caused by a minor discrepancy of 11%). Very
major discrepancy was found only for CI 1%, Cef32 0.7%
and Cef 256 0.3%; and none for the other antimicrobial
agents. There was no major discrepancy was for any
antimicrobial agents.
Conclusion: The new MICE strips to determine MICs
demonstrated an excellent a performance for the interpretive
category determinations of SIR of the antimicrobial
agents tested.
O088
A practical aid for detection of extended-spectrum beta-lactamases
in Enterobacteriaceae
N. al Naiemi, Y.J. Debets-Ossenkopp, C.M. Vandenbroucke-
Grauls, P.H.M. Savelkoul
Dept. of Medical Microbiology and Infection Control, VU
University Medical Centre, Amsterdam
Introduction: The detection of Extended-Spectrum
Beta-Lactamases (ESBLs) is of special importance, because
this resistance genes present serious implications for
therapy. Currently, genotypic characterisation of ESBL
genes is considered the gold standard for ESBL identification.
However, the detection of ESBL genes with PCR and
sequencing is complex and does not provide information
about their expression. In this study, we evaluated the
performance of the combination of the molecular hyplex ®
Ned Tijdschr Med Microbiol 2008;16:Supplement
S36
ESBL ID (h-ES-ID) test and the ESBL screening agar (ESA)
in the identification of ESBL-producing Enterobacteriaceae
isolates.
Methods: The h-ES-ID is a multiplex-PCR-ELISA for the
direct detection of beta-lactamase-producing bacteria.
In the presence of relevant DNA, specific amplification
products of the blaTEM, bla SHV, bla CTX-M (except
CTX-M-8 ) and bla OXA-1 group are synthesised and
subsequently visualised with the h-ES-ID hybridisation
modules. The ESA is a MacConkey agar with third
generation cephalo sporins, AmpC beta-lactamase inhibitor
and vancomycin. We examined a total of 149 clinical
Enterobacteriaceae isolates, 61 of them had been previously
characterised as ESBL-producers with PCR and sequencing.
The other 88 isolates were ESBL negative.
Results: The sensitivity, specificity and duration of test of
h-ES-ID and ESA were 98% (60/61), 57% (50/88), 3 hours,
100% (61/61), 93% (82/88) and 18 hours respectively. With
the combination of h-ES-ID and ESA, all the ESBL-positive
and ESBL-negative isolates were detected correctly. CTX-M
ESBL producers were detected within 3 hours with h-ES-ID.
The low specificity of h-ES-ID was mainly due to TEM-1
producers among Escherichia coli isolates. These isolates
were correctly identified with the ESA..
Conclusion: The combination of h-ES-ID and ESA is a
quick, effective, and easy to use method for ESBL detection,
especially of CTX-M ESBLs, which are the most prevalent
ESBLs worldwide. This combination of tests provides
useful early therapeutic guidance by the rapid identification
of ESBL-positive isolates.
O089
Association between group A beta-haemolytic Streptococci
and vulvovaginitis in adult women: a case control study
M.J. Bruins1 , R.A.M.J. Damoiseaux 2 , G.J.H.M. Ruijs 1
1
Laboratory of Medical Microbiology and Infectious Diseases,
Isala klinieken, Zwolle, 2General Practice ‘De Hof van Blom’,
Hattem
Introduction: Vulvovaginitis including fluor vaginalis
accounts for approximately 250,000 visits in the
Netherlands to general practitioners (GPs) each year.
Guidelines for managing vaginal discharge mention
Candida albicans, Trichomonas vaginalis, bacterial
vaginosis, Chlamydia trachomatis and Neisseria gonorrhoeae
as the usual causes. Culturing for other agents is not
recommended, unless symptoms recur or persist despite
treatment. Lately, we noted a high isolation rate of
non-group B (A, C, F, G) beta-haemolytic Streptococci
from fluor vaginalis samples from women with recurrent
vulvovaginitis in our region. Group A Streptococci are
known as a cause of vulvovaginitis in children, but
evidence of infection in adult women is limited to a few