The Open Epidemiology
Molecular Epidemiology and Virulence Characteristics of
Klebsiella pneumoniae Strains Isolated from Hospital-Associated
Maria Damian, Codruta-Romanita Usein, Andi-Marian Palade, Stefania
Ceciu and Maria Cosman Pp 69-78
Purpose: The present study aimed to confirm by classical
and molecular laboratory methods hospital-associated outbreaks due
to virulent Klebsiella pneumoniae strains.
Methods: Eighty three Klebsiella pneumoniae strains
isolated from new-born patients, adults and hospital environment
and devices in five hospital units, were analyzed for resistance
to antibiotics, including last generation cephalosporins, sensitivity
to bacteriophages and pulsed-field gel electrophoresis profiles
in order to evaluate the epidemiological relatedness and their clonal
spreading. Polymerase chain reaction targeting fur genes and several
subtractive sequences (SL 002, SL 003, SL 019, SL 020, SL 021 and
SL 025) was used for virulence assessment.
Results: More than 50% of strains were resistant to third
generation cephalosporins and among them 69% were extended spectrum
beta-lactamase producers. Phage typing associated with pulse field
gel electrophoresis documented the clonal dispersion of strains.
Studying the distribution of virulence sequence, our results reveal
that fur gene is present in all strains and among the subtractive
sequences the most frequent is SL 020 followed by SL 019. None of
the analyzed sequences are present in all clinical isolates and
none of the bacterial strains carry all these sequences pointing
out the heterogeneity of Klebsiella pneumoniae population.
Conclusions: Phage typing method associated with pulse
field gel electrophoresis typing and genetic profile for virulence
indicated the occurrence of hospital associated-infections produced
by Klebsiella pneumoniae strains. Moreover, the results
reveal that virulence pattern could be used as a molecular marker
in order to define strains which are involved in the process of
the development of infectious diseases.