Genetic characterization of high-level gentamicin-resistant strains of Enterococcus faecalis in Iran

2004 ◽  
Vol 50 (10) ◽  
pp. 869-872 ◽  
Author(s):  
Mohammad Mehdi Feizabadi ◽  
Sorour Asadi ◽  
Maryam Zohari ◽  
Sara Gharavi ◽  
Gelavizh Etemadi
Keyword(s):  
Genetic Variation ◽  
Enterococcus Faecalis ◽  
Genetic Characterization ◽  
Enzyme Electrophoresis ◽  
Multilocus Enzyme Electrophoresis ◽  
Gentamicin Resistance ◽  
Resistant Strains ◽  
Plasmid Profiling ◽  
High Level

The prevalence of resistance to high levels of gentamicin among 182 isolates of Enterococcus faecalis from 2 Iranian hospitals was 42%. Gentamicin resistance was associated with conjugative plasmids (>70 kb) in most strains. Fingerprinting using EcoRI and HindIII showed genetic variation among these plasmids and gave evidence of nosocomial outbreaks and persistence of infection in different wards of the study hospitals, as well as transfer of plasmids between genetically diverse isolates. Using EcoRI, hospital-based specific plasmid fingerprints were detected for the isolates that had previously proved to be unrelated by multilocus enzyme electrophoresis, suggesting the persistence of related plasmids at each hospital, though minor changes in these related plasmids could be detected with HindIII.Key words: Enterococcus faecalis, HLGR, plasmid profiling, plasmid fingerprinting.

scholarly journals Genetic Characterization of Fluoroquinolone-Resistant Streptococcus pneumoniae Strains Isolated during Ciprofloxacin Therapy from a Patient with Bronchiectasis

2003 ◽  
Vol 47 (4) ◽  
pp. 1419-1422 ◽  
Author(s):  
Adela G. de la Campa ◽  
María-José Ferrandiz ◽  
Fe Tubau ◽  
Román Pallarés ◽  
Federico Manresa ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Genetic Characterization ◽  
Susceptible Strain ◽  
Low Level ◽  
Resistant Strains ◽  
Resistant Mutants ◽  
High Level ◽  
Level Resistance

ABSTRACT Five Spain9V-3 Streptococcus pneumoniae strains were isolated from a patient with bronchiectasis who had received long-term ciprofloxacin therapy. One ciprofloxacin-susceptible strain was isolated before treatment, and four ciprofloxacin-resistant strains were isolated during treatment. The resistant strains were derived from the susceptible strain either by a parC mutation (low-level resistance) or by parC and gyrA mutations (high-level resistance). This study shows that ciprofloxacin therapy in a patient colonized by susceptible S. pneumoniae may select fluoroquinolone-resistant mutants.

scholarly journals Structures, Locations, and Transfer Frequencies of Genetic Elements Conferring High-Level Gentamicin Resistance in Enterococcus faecalis Isolates in Greece

2003 ◽  
Vol 47 (12) ◽  
pp. 3950-3953 ◽  
Author(s):  
George L. Daikos ◽  
George Bamias ◽  
Christos Kattamis ◽  
Marcus J. Zervos ◽  
Joseph W. Chow ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Restriction Enzyme ◽  
Plasmid Dna ◽  
Strong Association ◽  
Hybridization Analysis ◽  
Clinical Isolates ◽  
Genetic Elements ◽  
Transfer Characteristics ◽  
Gentamicin Resistance ◽  
High Level

ABSTRACT The elements conferring high-level gentamicin resistance in 64 clinical isolates of Enterococcus faecalis were characterized by PCR and by restriction enzyme hybridization analysis of genomic and plasmid DNA. There was a strong association between gentamicin resistance and the aac(6′)-aph(2") gene carried on IS256-based elements with different structures, locations, and transfer characteristics.

scholarly journals Development of fluoroquinolone resistance in Enterococcus faecalis and role of mutations in the DNA gyrase gyrA gene.

1996 ◽  
Vol 40 (11) ◽  
pp. 2558-2561 ◽  
Author(s):  
J Tankovic ◽  
F Mahjoubi ◽  
P Courvalin ◽  
J Duval ◽  
R Leclerco
Keyword(s):  
Enterococcus Faecalis ◽  
Resistant Isolate ◽  
Fluoroquinolone Resistance ◽  
Gyra Gene ◽  
Single Clone ◽  
Total Dna ◽  
Resistant Strains ◽  
French Hospital ◽  
High Level

We have analyzed the development of fluoroquinolone resistance between 1986 and 1993 among clinical isolates of Enterococcus faecalis from a French hospital. One hundred randomly selected isolates per year were screened for resistance to ciprofloxacin (MIC > 2 micrograms/ml) and for high-level resistance to gentamicin (MIC > 1,000 micrograms/ml). The percentages of ciprofloxacin-resistant strains for these years were as follows: 1986, 0; 1987, 1; 1988 to 1989, 2; 1990, 6; 1991, 16; 1992, 24; and 1993, 14. Eighty-three percent of the ciprofloxacin-resistant isolates were coresistant to high levels of gentamicin. Forty-eight high-level gentamicin-resistant E. faecalis strains, which were resistant (24 strains) or susceptible (24 strains) to ciprofloxacin, were examined by pulsed-field gel electrophoresis (PFGE) of SmaI-digested total DNA. Numerous PFGE types were observed among the ciprofloxacin-susceptible isolates, whereas one type was largely predominant among the ciprofloxacin-resistant strains, which suggests that the increase in fluoroquinolone resistance was due to the spread of a single clone. A 241-bp fragment of gyrA, corresponding to the quinolone resistance-determining region, was amplified and sequenced for seven ciprofloxacin-resistant isolates. Six strains had high levels of resistance (MICs, 32 to 64 micrograms/ml) and had a mutation at position 83 (Escherichia coli coordinates) from Ser to Arg (three strains) or to Ile (two strains) or at position 87 from Glu to Gly (one strain), whereas the low-level-resistant isolate (MIC, 8 micrograms/ml) had no mutations.

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