Detection of Van-Positive and Negative Vancomycin Resistant Entrococci and their Antibacterial Susceptibility Patterns to the Newly Introduced Antibiotics
Abstract:
The aim of this study was to determine the types and
frequencies of VRE in terms of the existence of Van genes and to
investigate the efficacy of newly introduced antibiotics. Totally 297
enterococcal strains were isolated from patients’ specimens. Minimum
inhibitory concentration of resistant isolates to vancomycin and tecoplanin
were determined by E test method. Simultaneous detection of Van
genes and species identification was preformed using multiplex PCR. Sensitivity
patterns of VRE isolates to several antibiotics were determined by disk
diffusion (Kirby-Bauer) method. One hundred and four (35%) of the isolates
were VRE of which 12.5, 10.5 and 7% from urine, blood and stool samples
were detected, respectively. Resistant isolates were sensitive to tigecycline
and linezolid and resistant to ciprofloxacin and amikacin. The isolates
which were resistant to ciprofloxacin, amikacin and gentamicin also showed
cross-resistance to the other tested antibiotics. VanA is the predominant
gene of Van-positive isolates in Iran. Meanwhile, the prevalence
of Van-negative intermediate VRE in E. fecalis is markedly
increased. These findings lend support to the hypothesis that due to frequent
vancomycin administration in our clinics the acquisition of Van
genes as well as selection of resistant mutant isolates could be facilitated.
Rational prescription of vancomycin and wisely administration of newly
introduced antibiotics like tigecycline and linezolid is warranted.
A. Japoni, S. Farshad, M. Ziyaeyan and S. Ziaian, 2009. Detection of Van-Positive and Negative Vancomycin Resistant Entrococci and their Antibacterial Susceptibility Patterns to the Newly Introduced Antibiotics. Pakistan Journal of Biological Sciences, 12: 844-851.
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