Clonal groups of high-level gentamicin-resistant Enterococcus faecium isolated from municipal wastewater and clinical samples in Tehran, Iran.
OBJECTIVE
Clonality among high-level gentamicin-resistant Enterococcus faecium (HLGR-EF) isolates obtained from clinical and sewage treatment plants (STP) were investigated using PhePlate system (PhP), ribotyping and pulsed-field gel electrophoresis (PFGE).


RESULTS
During 1 year study (September 2005-2006), a total of 106 HLGR-EF isolates were collected from clinical (n = 48) and STP (n = 58) samples in Tehran, Iran. Biochemical fingerprinting of these isolates using the PhP showed the presence of 21 PhP types (diversity index, Di = 0.97) among the clinical and 21 PhP types (Di = 0.91) among the STP isolates. Representative isolates of each PhP type (n = 42) were further characterized by the ribotyping method. Sixteen ribotypes were identified among the isolates with five types shared between the clinical and STP isolates. PFGE recognized 24 clonal types among these isolates with three pulsotypes shared between the clinical and STP isolates. Combination of the two techniques (PFGE and ribotyping) resulted in 24 (Di = 0.96) and 16 (Di = 0.93) types among the strains isolated from clinical and STP samples, respectively.


CONCLUSIONS
We concluded that the combination of PhP typing, ribotyping and PFGE could be extremely discriminatory when examining HLGR-EF isolates.


CONCLUSIONS
The emergence of highly diverse HLGR-EF population in Iran is of serious concern especially because of their multi-resistances.
Saifi
M
M
Department of Microbiology, Pasteur Institute of Iran, Tehran, Iran.
Pourshafie
M R
MR
Dallal
M M Soltan
MM
Katouli
M
M
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015373:Bacterial Typing Techniques / Q000379:methods; D016000:Cluster Analysis; D016172:DNA Fingerprinting / Q000379:methods; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D016984:Enterococcus faecium / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D005838:Genotype; D005839:Gentamicins / Q000494:pharmacology*; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology*; D006801:Humans; D007492:Iran; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D021521:Ribotyping; D014871:Water Microbiology
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D005839:Gentamicins