Multiple Antibiotic-resistant Enterococci Research Articles

Incidence of enterococci resistant to clinically relevant antibiotics in environmental waters and in reclaimed waters used for irrigation.

Treated wastewater discharged into the environment or reused in different activities can be a major vehicle for the transmission of antibiotic-resistant bacteria and antibiotic-resistance genes. In this study, environmental and wastewater samples, collected at different stages of treatment, were studied to identify the possibility of a positive selection of antibiotic-resistant organisms in wastewater treatment plants (WWTPs). Enterococci were isolated, characterized into the main human species, and subjected to the Kirby-Bauer test using seven antibiotics (five classes): ampicillin, chloramphenicol, ciprofloxacin, gentamicin, linezolid, tetracycline, and vancomycin. Furthermore, vancomycin-resistant enterococci (VRE), a major cause of nosocomial infection, was identified, and the genes vanA and vanB detected directly in the samples and in all confirmed VRE. Data showed that WWTPs were able to reduce the levels of antibiotic resistance, although 72% of the disinfected wastewaters still presented antibiotic-resistant enterococci. VRE were detected in 6% of the samples, including in reclaimed waters. UV disinfection was not effective at removing VRE and multiple antibiotic-resistant (MAR) enterococci, most commonly Enterococcus faecalis. The use of reclaimed water containing VRE and MAR enterococci in crop production, irrigation of urban gardens, and street cleaning increases immensely the potential risk to human health.

Virulence profiles of vancomycin-resistant enterococci isolated from surface and ground water utilized by humans in the North West Province, South Africa: a public health perspective.

Vancomycin-resistant enterococci (VRE) have been responsible for numerous outbreaks of serious infections in humans worldwide. Enterococcus faecium and Enterococcus faecalis are the principal species that are frequently associated with vancomycin resistance determinants, thus usually implicated in hospital- and community-acquired infections in humans. The study aim was to determine the antibiotic resistance and virulence profiles of VREs isolated from surface and groundwater samples that are used by humans in the North West Province, South Africa. A total of 170 water samples were collected and analyzed. Eighty-one potential isolates were screened for characteristics of Enterococcus species using preliminary biochemical tests, PCR assays and sequence analysis. The antimicrobial resistance profiles of the isolates against nine antibiotics were determined and a dendrogram was generated to access the relatedness of the isolates. The isolates were screened for the presence of antibiotic resistance and virulence genes by multiplex PCR analysis. A total of 56 isolates were confirmed as Enterococcus species and the proportion of E. faecium (46.9%) was higher than E. faecalis (29%) and E. saccharolyticus (1.2%). Sequence data of E. faecium, E. faecalis, and E. saccharolyticus isolates revealed 97 to 98% similarities to clinical strains deposited in NCBI Genbank. Large proportions (44; 78.6%) of the isolates were resistant to vancomycin while 16 and 3.6% of the isolates possessed the vanA and vanB genes respectively. The MAR phenotype Vancomycin-Nalidixic Acid-Streptomycin-Chloramphenicol-Ampicillin-Oxytetracycline-Gentamycin-Nitrofurantoin-Sulphamethoxazole indicated that some isolates were resistant to all of the nine antibiotics tested. Cluster analysis of antibiotic resistance data revealed two major clusters. Sixteen (36.4%), 14 (27.3%), 3 (6.8%), and 2 (4.5%) of the VRE isolates possessed the gel, asa1, hyl, and esp virulence genes respectively while the cylA gene was not detected in the study. Multiple antibiotic-resistant enterococci were also resistant to vancomycin and possessed virulence determinants indicating that they can pose severe public health complications on individuals who consume contaminated water.

Vancomycin-resistant enterococci in Saudi Arabia: prevalence, antibiotic resistance and susceptibility array

Vancomycin-resistant Enterococci (VRE) are an important cause of nosocomial infection and may result in increased morbidity and mortality in immunocompromised populations particularly in developing contries. The aim of the present study was to reassess the definition of hospitalacquired Enterococci, with particular emphasis on the relevance of recent hospitalization.Total 228 Enterococci clinical samples were collected from different hospitals of Saudi Arabia. Sampling was performed following sub culturing, strains isolation and antimicrobial susceptibility testing. Out of 228 Enterococci clinical isolates isolated in this study, 186 (82%) were susceptible to vancomycin, 17 (7%) were resistant and 25 (11%) were intermediate. Most of VRE isolated in our study were from Jeddah hospitals 11%. The most common infections caused by Enterococci in current study showed urinary tract infection (56.6%) followed by blood (12.3%) and wound infection (11.4%). Porportion of 87% and 13% Enterococci isolated in this study were from Saudi and non-Saudi patients respectively and were calculated statistically nonsignificant (p-value=0.4). This limited study exhibited a high pervasiveness rate of multiple antibiotic resistant Enterococci infections among hospitalized patients in this environment. There is need for precise observations of clinics and hospitals for Enterococci infections; prudent use and rational prescription of antimicrobials and stringent measures to reduce the prevalence rate by health education on infection control measures such as isolation, cleaning, disinfection and

Phenotypic Diversity of Multiple Antibiotic Resistant Enterococci with Emphasis on Enterococcus gallinarum Carrying vanA and vanB Genes

The prevalence and diversity of antibiotic resistant enterococci populations in samples collected four times from urban sewage treatment plant in Tehran, Iran between June 2005 and July 2006 were studied. Filtered samples were grown on mEnterococci medium containing 4 μg/ml vancomycin after which the enterococci isolates were identified to the species level. All strains were then tested for their resistance against nine antibiotics. Of the 131 isolates, 98 (75%) isolates were identified as Enterococcus gallinarum, followed by 24 (18%) and 9 (7%) for E. faecium and E. casseliflavus, respectively. All E. gallinarum isolates carried vanC1 gene with 64 (65%) and 14 (14%) isolates concomitantly harboured either vanA or vanB gene, respectively. Some E. casseliflavus concomitantly harboured vanA and vanC2 or vanB and vanC2. Typing the total enterococci isolates with a high resolution biochemical fingerprinting method showed a high diversity (Di = 0.91). We have shown by biochemical fingerprinting the presence of highly diverse glycopeptide resistant E. gallinarum and E. casseliflavus that have captured vanA and vanB genetic determinants under natural conditions. To our knowledge this is the first report in this geographical region showing high frequency antibiotic resistant enterococcal populations in particular E. gallinarum carrying assorted vancomycin resistance genes.