INVESTIGADORES
MARTINA Pablo Francisco
congresos y reuniones científicas
Título:
Discrimination of clinical and environmental isolates of Burkholderia contaminans, a high prevalent species within Taxon K of Burkholderia cepacia Complex, using PCR fingerprinting genotyping and FT-IR spectroscopy-based phenotyping
Autor/es:
PABLO MARTINA, GONZALO SEQUEIRA, ALEJANDRA BOSCH, ANTONIO LAGARES, AND OSVALDO YANTORNO*
Lugar:
Berlin, Alemania
Reunión:
Workshop; International Workshop "FT-IR Spectroscopy in Microbiological and Medical Diagnostics"; 2009
Institución organizadora:
Robert Koch Institute.
Resumen:
Burkholderia cepacia Complex (BCC) species are responsible for
devastating lung infections in cystic fibrosis (CF) patients and
various infections in inmunocompromised non-CF patients. In
common with many other opportunistic pathogens, it appears that
severe disease and death depend on the clinical state and
predisposition of the patients at the time of infection . BCC bacteria
used to be mainly patient-to-patient transmitted. Nevertheless, due
to the implementation of strict infection control practices in
hospitals and to the education of patients the transmission of
bacteria among them has been significantly reduced in the last
years. However, these stringent infection control measures do not
prevent the acquisition of BCC organisms from industrial settings,
industrial products, or the natural environments . In the last years,
bacteria belonging to Group K or Taxon K of BCC have been
isolated from sputum cultures of CF patients, in the UK, Italy,
Portugal, USA, Canada, Brazil and Argentina, and have also been
recovered from environmental samples such as river water, soil,
roots, animals, industrial pharmaceutical products, personal care
products, and domestic products. Particularly, in Argentina Taxon K
represents around 13% of the species recovered from sputum
samples of CF patients and almost 80% of the BCC isolates. These
isolates are characterized by exhibiting yellow-green pigment and
â-haemolysis and have the HaeIII recA-RFLP K pattern being
accurate identified by recA gene sequencing.In this work whole cell FT-IR spectroscopy fingerprinting has been
used together with hierarchical cluster analysis (HCA) to study
clinical and industrial setting isolates belonging to B. contaminans
species and to compare its typing schemes with genomic profiles
based on repetitive intergenic consensus PCR (BOX-PCR).Fifty clinical isolates and 10 industrial setting isolates identified as
B. contaminans by recA sequencing were used. Like most
phenotyping approaches, FT-IR spectroscopy samples had to be
prepared under strict standardization culture conditions (growth
medium, incubation time and temperature), and particularly for BCC
species, we previously reported that spectra had to be acquired
avoiding polyhidroxy acids (such as PHB) accumulation and
removing pili and/or other protein appendages that might produce
interference in IR spectra .Molecular typing by PCR fingerprinting revealed a relatively high
level of genotypic diversity showing at least 6 different variants for
B. contaminans clinical isolates. In addition no evidences of genetic
similarities were found between B. contaminans isolates from
industrial settings and clinical isolates. HCA obtained with first
derivative spectra analyzed in 3 mid IR ranges successfully
confirmed the distinct genotypes within clinical isolates and was
also capable to distinguish isolates derived from industrial settings
providing therefore, a valuable taxonomic information.We conclude that both PCR fingerprinting and FT-IR spectroscopy
methods can be helpful tools for global epidemiological studies.
Particularly, FT-IR spectroscopy can be considered a simple and
rapid methodology for differentiating B. contaminans strains in sets
of isolates obtained during outbreaks contributing to the control of
infection spreading, for answering questions of clonality among
microbial isolates, and also for allowing the identification of the
strains that have the higher degree of transmissibility.