Introduction: The extensive use of antibiotics has led to the emergence of
multi-resistant strains in some species of the genus
Acinetobacter.
Objective: To investigate the molecular characteristics of multidrug-resistant
of
Acinetobacter ssp. strains isolated from 52 patients collected between March
2009 and July 2010 in medical intensive care units in Cali - Colombia.
Methods: The susceptibility to various classes of antibiotics was
determined by disc diffusion method, and the determination of the
genomic species was carried out using amplified ribosomal DNA
restriction analysis (ARDRA) and by sequencing of the 16s rDNA
gene. Also, the genes of beta-lactamases as well as, integrases IntI1 and
IntI2 were analyzed by PCR method.
Results: The phenotypic identification showed that the isolates belong
mainly to
A. calcoaceticus
-
A. baumannii
complex. All of them were
multi-resistant to almost the whole antibiotics except to tigecycline and
sulperazon, and they were grouped into five (I to V) different antibiotypes,
being the antibiotype I the most common (50.0%). The percent of beta-lactamases
detected was: blaTEM (17.3%), blaCTX-M (9.6%), blaVIM
(21.2%), blaIMP (7.7%), blaOXA-58 (21.2%), and blaOXA-51 (21.2%).
The phylogenetic tree analysis showed that the isolates were clustering to
A. baumannii (74.1%),
A. nosocomialis
(11.1%) and
A. calcoaceticus (7.4
%). Besides, the integron class 1 and class 2 were detected in 23.1% and
17.3% respectively.
Conclusion: The isolates were identified to species
A. baumanii mainly,
and they were multiresistant. The resistance to beta-lactams may be by for
presence of beta-lactamases in the majority of the isolates.
