EVALUATION OF THE EXPRESSION OF MexY EFFLUX PUMP IN
FLUOROQUINOLONE-RESISTANT Pseudomonas aeruginosa
Tonani, L.1; Clímaco, E.C.1; Darini, A.L.C1
1-Faculdade de Ciências Farmacêuticas de Ribeirão Preto - Universidade de São Paulo, Ribeirão Preto,
SP, Brasil.
Keywords: Hospital infection, efflux pump, Pseudomonas aeruginosa, multidrug resistence.
1. Introduction
3. Results
Pseudomonas aeruginosa is the most important
Susceptibility rates of the studied isolates showed
pathogenic non-fermenting bacteria, especially in
36.6% (15/41) for ciprofloxacin and norfloxacin
nosocomial infections. This specie is often
and 34,2% (14/41) for levofloxacin. These results
associated
(MDR)
are in accordance to SENTRY data published by
phenotype. One of the main MDR mechanisms in
Gales et al. (2002) that showed 38,6% and 36% of
P. aeruginosa is MexXY-OprM efflux pump,
susceptible P. aeruginosa to ciprofloxacin and
which confers resistance against antipseudomonal
levofloxacin, respectively.
penicillins,
and
Results from evaluation of MexY expression
if
showed that there was statistical significance
reduced
to
multidrug
resistance
cephalosporins,
susceptibility
to
quinolones
meropenem,
overexpressed. The aim of this work is to
(P<0,05)
in
the
relationship
between
determine if the over expression of MexY pump is
fluoroquinolone susceptibility profile and 2-∆CT
responsible for the increasing of fluoroquinolone
values, with P value of 0.0006, for ciprofloxacin
resistence in P. aeruginosa strains.
and norfloxacin, and of 0.0013, for levofloxacin
(Figure 1).
2. Methods
It was used 41 P. aeruginosa isolates recovered
Figure
from pacients of University Hospital of Federal
according
University of Juiz de Fora. Firstly, the
fluoroquinolones.
1.
Distribution of
to
2-∆CT
clustered
susceptibility
against
susceptibility profiles of these isolates were
investigated by disc diffusion according to CLSI
criteria. Expression assay of MexY gene was
carried out by real time PCR, using Fast
EvaGreen system, after RNA purification with
RNAeasy
kit
and
reverse
transcription.
Analyzing of real-time PCR data was realized
by comparative 2-∆Ct method, using RpsL
4. Conclusion
housekeeping gene expression to normalize
MexY
gene
fluoroquinolones
expression.
susceptibles
Results
and
of
The results suggest that there was a high
non-
correlation between MexY overexpression and
susceptibles isolates were compared by t test
method of non-parametric and independent
resistance phenotype to fluoroquinolone.
Acknowledgments
samples, to determine whether the difference is
statistically significant.
We thank FAPESP for financial support.