Couet, W.

Gaspar, M.

Olivier, J.-C.

Pais, A.

Sousa, J.

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88 Development of microspheres for pulmonary administration in cystic fibrosis lung disease 

S70 5. Microbiology − Antibiotics Posters
84 Azithromycin resistance in Prevotella species isolated from
CF patients
L. Sherrard1, K.A. Graham1, S.J. McGrath1, L. McIlreavey1, J. Hatch2,
M. Muhlebach2, D.F. Gilpin1, J.S. Elborn1, T. Schneiders1, M. Tunney1. 1Queen’s
University, CF & Airways Microbiology Group, Belfast, United Kingdom;
2University of North Carolina at Chapel Hill, North Carolina, United States
Objective: The use of chronic azithromycin treatment has been linked with in-
creased macrolide resistance. Although, Prevotella spp. are one of the most common
anaerobes detected in CF pulmonary samples, the effect of chronic azithromycin
exposure on this genus is unknown. The aims of this study were to
i. investigate if resistance is associated with azithromycin prescription
ii. compare azithromycin and clindamycin MICs between Prevotella isolates cul-
tured from CF patients and healthy control subjects.
Methods: Isolates were grouped according to source and patient prescription of
azithromycin: CF (currently prescribed), n = 27; CF (not currently prescribed),
n = 30; healthy controls (none), n = 17. Susceptibility was determined by Etest®
and MICs compared between groups using the Mann-Whitney test.
Results: CF isolates had signiﬁcantly higher azithromycin and clindamycin
MICs compared to the healthy control isolates (P < 0.001). Current prescrip-
tion of azithromycin was associated with signiﬁcantly higher azithromycin MICs
(P= 0.016) in the CF isolates. CF isolates (not currently prescribed) had signif-
icantly higher azithromycin MICs (P= 0.009) compared to isolates from healthy
control subjects. Isolates from the 2 CF groups had equal resistance to clindamycin
(P= 0.228).
Conclusions: CF patients harbour isolates with increased resistance to azithromycin
and clindamycin. Azithromycin resistance is associated with current azithromycin
prescription. Work supported by a Department of Employment and Learning,
NI (DEL) studentship to L. Sherrard and by HSC Research and Development,
Public Health Agency, NI and the Medical Research Council through a US-Ireland
Partnership Grant.
85 Investigation into the antibiotic resistome of the Streptococcus
genus from adult cystic ﬁbrosis patients
C.S. Thornton1, M.E. Grinwis1, C.D. Sibley1, H.R. Rabin2, M.G. Surette3.
1University of Calgary, Microbiology & Infectious Diseases, Calgary, Canada;
2University of Calgary, Adult Cystic Fibrosis Clinic, Calgary, Canada; 3McMaster
University, Medicine and Biochemistry and Biomedical Sciences, Hamilton,
Canada
Objectives: The lower airways of CF patients are colonized by polymicrobial
communities in which streptococci are prominent and are implicated in driving
exacerbations. Multiple streptococci are present in sputum, including several novel
species. Given their prominence in the CF airway microbiome and the capacity
for horizontal gene transfer, our objectives were to determine rates of antibiotic
resistance and molecular mechanisms of macrolide resistance.
Methods: 459 streptococcal isolates from 68 adult CF patients comprising of 16
novel and typed species underwent susceptibility testing for nine antibiotics used
in CF management. Molecular mechanisms of resistance for the macrolides were
determined by a PCR screen and sequencing.
Conclusion: 84% of isolates had multi-drug resistance to 3+ antibiotics. Resistance
was greatest for macrolides at 51.6% (erythromycin) and 56.4% (azithromycin),
but with novel isolates at 80%. The most common mechanisms of macrolide
resistance acquired by horizontal gene transfer, the mef (efﬂux pump) and erm
(target site methylation) accounted for only 53% of resistant isolates. Signiﬁcantly,
23S ribosomal point mutations accounted for 47% of resistant isolates. This is not
thought to be a common mechanism of macrolide resistance in the streptococci.
The prevalence, species distribution and inﬂuence of therapy on resistance proﬁles
suggest complex ecological interactions among the streptococci in CF airways
with mutation, rather than only horizontal gene transfer, contributing to acquired
antibiotic resistance in this community. This is in contrast to previous studies and
may reﬂect differences in strain isolation or patient populations.
86 Real time genome sequencing to decipher the molecular
mechanism of resistance of Chryseobacterium oranimense, a new
multidrug resistant species isolated from a cystic ﬁbrosis patient
P. Sharma1, S. Diene1, S.K. Gupta1, C. Robert1, M. Reynaud-Gaubert1,
J.-C. Dubus1, J.-M. Rolain1. 1URMITE CNRS Aix Marseille University, Marseille,
France
Objective: The objective was to sequence the genome of Chryseobacterium orani-
mense, a multidrug resistant gram negative, yellow-pigmented bacterium from a
cystic ﬁbrosis patient in France.
Methods: Antibiotic susceptibility test was done using disc diffusion method and
Etest assays. Whole genome sequencing was performed for the strain using PGM
technology and sequences obtained were used to identify all antibiotic resistance
(AR) determinants.
Results: The genome size is 4.45 bp. The G+C content is 37.7% assembled into
15 contigs. The MIC for imipenem and colistin was 12 mg/ml and 24mg/ml,
respectively. Whole resistome analysis shows the presence of an IND-4 like
carbapenemase, as well as macrolide, tetracycline, rifampin, sulphonamide and
ﬂuoroquinolone AR genes. We found operons for Lipid A modiﬁcations and
exopolysaccharide synthesis which could explain the resistance to colistin. We also
found an operon for polyketide synthase likely involved in the biosynthesis of a
macrolide compound and a zeaxanthin operon explaining the yellow pigmentation
of this strain.
Conclusions:Whole genome sequencing provides insights into the molecular mech-
anism responsible for phenotypic properties of this multidrug resistant bacterium.
The polyketide synthase operon found in the genome is reported for the ﬁrst time
and antimicrobial activity against a panel of bacterial strains is under investigation.
Chryseobacterium species have been reported from environmental sources such as
plants, vegetables or aquatic habitats and therefore may represent the source of
transmission of this bacterium to humans.
87 Development of microspheres for pulmonary administration in
cystic ﬁbrosis lung disease
M. Gaspar1, W. Couet2,3, J.-C. Olivier2,3, A. Pais4, J. Sousa1. 1University
of Coimbra, Faculty of Pharmacy, Center for Pharmaceutical Studies (CEF),
Pharmaceutical Technology, Coimbra, Portugal; 2INSERM, U 1070, Poitiers,
France; 3University of Poitiers, School of Medicine and Pharmacy, Poitiers,
France; 4University of Coimbra, Chemistry Department, Coimbra, Portugal
Objectives: Cystic Fibrosis (CF) is a complex inherited disease, affecting partic-
ularly the respiratory system. The objective of this work is the development of
drug microspheres directed at the treatment of Pseudomonas aeruginosa, which
is the main cause of chronic airway infection in CF. These microspheres may
target speciﬁc regions of the respiratory tract, reducing systemic toxicity and the
frequency of drug administration, and increasing patients’ compliance. Possessing
the appropriate physical properties, they facilitate the dispersion of therapeutic
agents in the inhaled air and reduce the deposition in the oropharynx and may
modulate release kinetics.
Methods: Levoﬂoxacin or ciproﬂoxacin loaded-microspheres prepared with low
molecular weight chitosan were obtained by the spray drying technique. Particle
size was determined by laser light diffraction, and optimised on the basis of
some formulation and operational variables, resorting to experimental design.
The analysis was complemented with optical, ﬂuorescence and scanning electron
microscopy (SEM), which provided additional insight on agglomerate formation
and morphology. Aerodynamic studies have also been performed with an impactor,
in order to evaluate lung distribution.
Conclusion: The prepared chitosan microspheres present an average diameter
within the optimal interval for pulmonary administration (1−5mm), and are spherical
with a smooth surface. Higher polymer concentrations promote larger diameters and
higher values of drug loading, while temperature and airﬂow are less relevant for
the ﬁnal properties of the microspheres.


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88 Development of microspheres for pulmonary administration in cystic fibrosis lung disease

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