Abstract
Enterococcus faecalis has emerged as an important nosocomial pathogen worldwide, infections and outbreaks of Vancomycin-resistant enterococci (VRE) still appear to be rare in Baghdad. In the present study, 20 isolates of E. faecalis were collected from 252 clinical samples (151 urine and 101 blood) from different hospitals in Baghdad and 3 isolates from 50 stool samples from healthy people during the period 1/10/2010 to 1/12/2010. All isolates were identified through morphological, cultural and biochemical tests using Rapid ID-32 strep. Vancomycin-resistance phenotype was determined by the agar diffusion method; results showed that five clinical isolates (25%) and two faecal isolates (66.7%)were resistant to vancomycin. Minimum inhibitory concentrations (MIC) of clinical VRE isolates ranged between 4 to 512 µg/ml and the MICs for isolates of faecal origin were 64 and 128 µg/ml. Seven vancomycin-resistant E. faecalis isolates were examined for their drug resistance and plasmid DNAs. Of the 5 clinical isolates, 2 isolates exhibited resistance to azlocillin (Azl) and ofloxacillin (Ofx). All clinical and stool isolates were resistant to oxacillin (Ox), cefepime (Fep), rifampicin (Ra) and tetracycline (Te). Imipenem and ampicillin were found to be the most effective agents against the isolates. The detection of plasmid DNA by gel electrophoresis showed that some E. faecalis isolates carried a high molecular weight plasmid that was transferred to the recipient by filter mating. The putative presence of vanA gene was examined by PCR, using specific primers. Positive PCR amplifications were obtained in all 7 isolates for vanA gene.Vancomycin resistant E. faecalis increased gradually in Baghdad hospitals and high dissemination of vanA gene, which encoded high resistance level to vancomycin. Continued surveillance is required to prevent further spread of these serious resistances. Key words: Bacteria, vancomycin, Enterococcus faecalis
Highlights
Enterococci are known to be opportunistic nosocomial pathogens capable of causing life-threatening infections, such as endocarditis and bacteremia, mostly in immunocompromised patients (Levison and Mallela, 2000) occasionally reported to cause urinary tract infections, septicemia, and endocarditis (Sun et al, 2009)
In Iraqi hospitals, very rare studies have investigated the incidence of vanA gene among Vancomycin resistant Enterococcus faecalis, The aims of this study were to determine the distribution of Vancomycin-resistant E. faecalis isolates, and studying the vanA gene in this bacteria which isolated from hospitals and healthy persons
Four clinical isolates were resistant to streptomycin, two isolates were resistant to ofloxacin, and one stool isolate was resistant to Ampicillin
Summary
Enterococci are known to be opportunistic nosocomial pathogens capable of causing life-threatening infections, such as endocarditis and bacteremia, mostly in immunocompromised patients (Levison and Mallela, 2000) occasionally reported to cause urinary tract infections, septicemia, and endocarditis (Sun et al, 2009). The emergence of vancomycin-resistant enterococci (VRE) followed a worst-case scenario for nosocomial pathogens. The isolation of VRE (VanA type) was first reported in 1988 in the United Kingdom (Uttley et al, 1988) and France (Leclercq et al, 1988), and shortly thereafter, it was reported in the United States (Sahm et al, 1989). Vancomycin resistance is conferred by one of two functionally similar operons, vanA or vanB. The vanA and vanB operons are highly sophisticated resistance determinant, probably evolved in other species and acquired by enterococci (Rice, 2001).
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