Objectives
Enterococcus faecalis
as part of the normal floras of human gastrointestinal and genitourinary tracts are an important cause of nosocomial infections. The present study aimed to investigate the prevalence of genes encoding antimicrobial resistance and genetic relatedness of clinical isolates of
E. faecalis
among Iranian hospitalized patients.
Results
Antibiotic susceptibility testing results indicated that 53 (22.8%) out of 232
E. faecalis
isolates were vancomycin resistant (MIC ≥ 256 μg/ml). All of the 53 vancomycin-resistant
E. faecalis
isolates carried the
vanA
and
ermB
genes; whereas
aac (6′)
-
Ie aph (2″)
,
msrA
, and
ermA
gene were found in 96.2%, 30.2% and 3.8% of vancomycin-resistant isolates, respectively. ERIC-PCR typing revealed that 53 vancomycin-resistant isolates were classified into 14 ERIC types. In our results, the high level of resistance to gentamicin, erythromycin and vancomycin in enterococci isolates were mainly related to the presence
of aac (6′)
-
Ie aph (2″), ermB
and
vanA
genes, respectively. Meanwhile, ERIC-PCR analysis demonstrated that most of the evaluated isolates have a close genetic relatedness.
Background: Biofilm formation capacity is recognized as an important virulence factor in staphylococci that makes the organisms more resistant to antibiotics and host defenses. Objectives: This study aimed to determine the biofilm producing ability and presence of icaA/D genes in staphylococcal isolates obtained from different clinical specimens. Methods: This cross-sectional study was performed on a total of 151 staphylococcal isolates (79 Staphylococcus aureus and 72 S. epidermidis) obtained from different clinical specimens from February to August 2013 in Shiraz, Southwest of Iran. Slime production ability was evaluated using the both phenotypic (by cultivation of staphylococcal isolates on Congo red agar (CRA)) and genotypic (detection of the presence of icaA/D genes by PCR) methods. Results: Overall, of the 79 S. aureus isolates tested with CRA method, 64.7% of methicillin-resistant S. aureus (MRSA) isolates, and 46.7% of methicillin-sensitive S. aureus (MSSA) isolates were able to produce biofilm. The relative frequency of biofilm producing S. epidermidis isolates was 70.8% that was significantly higher than that of S. aureus isolates. The most common source of biofilm producing isolates in both S. aureus and S. epidermidis isolates was endotracheal tube (ETT) with 100% biofilm formation. Moreover, the presence of icaA/D genes was detected in 63.3% and 81.9% of S. aureus and S. epidermidis isolates, respectively. Conclusions: The remarkable rates of biofilm production ability among clinically isolated staphylococci emphasize the necessity of more effective infections control policies to prevent biofilm formation on medical devices and hospital environmental surfaces.
PurposeOver the past two decades, enterococci have emerged as an important opportunistic pathogen causing life-threatening infections in hospitals. The purpose of the present study was to examine the prevalence of genes encoding virulence factor and molecular characterization of vancomycin-resistant E. faecalis strains isolated from hospitalized patients in Isfahan, the central city of Iran.Patients and methodsA total of 53 vancomycin-resistant E. faecalis isolates (VRE) obtained from clinical samples of hospitalized patients were characterized by phenotypic and genotypic methods, and 25 selected VRE isolates from internal and ICU wards were typed by multilocus sequence typing.ResultsThe efa was the most prevalent virulence gene (100%) among isolates, followed by gelE (92.45%), asa1 (90.56%), ace (86.79%), esp (75.47%), cylA (39.62%), and hyl (18.86%). More than 80% of the isolates were HLGR. Multilocus sequence typing showed eight different sequence types including ST6, ST422, ST28, ST448, ST531, ST328, ST421, and ST495. STs were grouped into two clonal complex (CC) including CCA (ST6, ST422, ST448, ST531) and CCF (ST28, ST421) and two singletons (ST328, ST495).ConclusionOur data indicated a high prevalence of virulence genes among STs described in this study. In addition, the molecular analysis demonstrated a relatively high genetic diversity among selected VRE strains from the ICU in comparison with the internal ward. Therefore, in order to prevent the colonization of virulent strains in the hospital environment, infection control procedures should be performed.
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