Vancomycin-resistant Enterococcus Faecium Strains Research Articles

Evolution and mutations predisposing to daptomycin resistance in vancomycin-resistant Enterococcus faecium ST736 strains.

We recently identified a novel vancomycin-resistant Enterococcus faecium (VREfm) clone ST736 with reduced daptomycin susceptibility. The objectives of this study were to assess the population dynamics of local VREfm strains and genetic alterations predisposing to daptomycin resistance in VREfm ST736 strains. Multilocus sequence typing and single nucleotide variant data were derived from whole-genome sequencing of 250 E. faecium isolates from 1994–1995 (n = 43), 2009–2012 (n = 115) and 2013 (n = 92). A remarkable change was noticed in the clonality and antimicrobial resistance profiles of E. faecium strains between 1994–1995 and 2013. VREfm sequence type 17 (ST17), the prototype strain of clade A1, was the dominant clone (76.7%) recognized in 1994–1995. By contrast, clone ST736 accounted for 46.7% of VREfm isolates, followed by ST18 (26.1%) and ST412 (20.7%) in 2013. Bayesian evolutionary analysis suggested that clone ST736 emerged between 1996 and 2009. Co-mutations (liaR.W73C and liaS.T120A) of the liaFSR system were identified in all ST736 isolates (n = 111, 100%) examined. Thirty-eight (34.2%) ST736 isolates exhibited daptomycin-resistant phenotype, of which 13 isolates had mutations in both the liaFSR and cardiolipin synthase (cls) genes and showed high level of resistance with a daptomycin MIC50 of 32 μg/mL. The emergence of ST736 strains with mutations predisposing to daptomycin resistance and subsequent clonal spread among inpatients contributed to the observed high occurrence of daptomycin resistance in VREfm at our institution. The expanding geographic distribution of ST736 strains in other states and countries raises concerns about its global dissemination.

Interactions of organic acids with vancomycin-resistant Enterococcus faecium isolated from community wastewater in Texas.

Investigate the interactions of organic acids (OAs), acetic, butyric, citric, formic, lactic and propionic acid against 50 Gram-positive vancomycin-resistant Enterococcus faecium (VRE) strains to determine whether pH, undissociated or dissociated acid forms correlate with bacterial inhibition. Concentrations of undissociated and dissociated OAs at the molar minimum inhibitory concentrations (MICM s) of the VRE were calculated using the Henderson-Hasselbalch equation. The pH at the MICM s of all VRE strains against acetic, butyric, formic and propionic acids was similar, 4·66±0·07, but there was a 1·1 pH unit difference for all six OAs. Inhibition of VRE by all six OAs did not appear to be solely dependent on pH or on the undissociated OA species. The inhibition of VRE by all six dissociated acids was within Δ=3·1mmoll-1 . Vancomycin-resistant Enterococcus faecium inhibition correlated with the dissociated OA species. A small decrease in the concentration of the dissociated OAs from optimum may result in allowing VRE strains to escape disinfection. When an OA is used to disinfect VRE strains, the concentration of the dissociated OA should be carefully controlled. A concentration of at least 20mmoll-1 dissociated OA should be maintained when disinfecting VRE.

Antimicrobial Photodynamic therapy enhanced by the peptide aurein 1.2

In the past few years, the World Health Organization has been warning that the post-antibiotic era is an increasingly real threat. The rising and disseminated resistance to antibiotics made mandatory the search for new drugs and/or alternative therapies that are able to eliminate resistant microorganisms and impair the development of new forms of resistance. In this context, antimicrobial photodynamic therapy (aPDT) and helical cationic antimicrobial peptides (AMP) are highlighted for the treatment of localized infections. This study aimed to combine the AMP aurein 1.2 to aPDT using Enterococcus faecalis as a model strain. Our results demonstrate that the combination of aPDT with aurein 1.2 proved to be a feasible alternative capable of completely eliminating E. faecalis employing low concentrations of both PS and AMP, in comparison with the individual therapies. Aurein 1.2 is capable of enhancing the aPDT activity whenever mediated by methylene blue or chlorin-e6, but not by curcumin, revealing a PS-dependent mechanism. The combined treatment was also effective against different strains; noteworthy, it completely eliminated a vancomycin-resistant strain of Enterococcus faecium. Our results suggest that this combined protocol must be exploited for clinical applications in localized infections as an alternative to antibiotics.

High prevalence of diverse vancomycin resistance Enterococcus faecium isolates in clinical and environmental sources in ICU wards in southwest of Iran

This study aimed at determining the prevalence, antibiotic resistance patterns, and genetic linkage of Vancomycin Resistant Enterococcus faecium (VREfm) from different sources in the southwest of Iran. A total of 51 VREfm isolates were obtained and subjected to antibiotic susceptibility testing, carriage of virulence genes, and pulsed-field gel electrophoresis (PFGE) method. All the VRE isolates exhibited a high level of resistance to teicoplanin, ampicillin, erythromycin, ciprofloxacin, and gentamicin, also carried the vanA gene. A total of 59% and 34% of the VREfm strains harbored esp and hyl genes, respectively. The results from PFGE showed 31 PFGE patterns including 10 common types (CT) and 21 single types (ST) among the VRE isolates. Furthermore, isolates from different sources in each common type revealed cross transmission between clinical and environmental sources. Overall, the study showed a high prevalence of diverse VRE faecium strains with threatening resistance phenotypes in the environment and clinical sections among different ICU wards of Ahvaz hospitals.

Antibacterial activity, computational analysis and host toxicity study of thymol-sulfonamide conjugates.

Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin resistant Enterococcus faecalis (VRE) are notorious pathogenic multidrug resistant (MDR) bacteria in both hospital and community sectors, and today the first antibacterial drug sulfamethoxazole is ineffective. The monoterpene phenol, thymol was conjugated with seven sulfa drug derivatives individually, adopting the dye-azo synthesis protocol, and conjugates were characterized using spectral analysis techniques such as, UV, FTIR, MS, HPLC, 1H NMR, 13C NMR and SEM. Conjugates were assessed for antibacterial activity in vitro and in silico; the zone of inhibition, MIC and MBC values of each conjugate were determined against isolated MRSA and VRE strains from clinical samples. As 3-dimentional structures of dihydropteroate synthases (DHPSs) of targeted bacteria are not available in protein database, homology models of DHPS enzymes of both bacteria were generated and validated by Ramachandran plots. Seven conjugates were used as ligands in molecular docking against MRSA-DHPS and VRE-DHPS. Additionally bioinformatics tools, PASS prediction, Lipinski rules of five, computational LD50 value, toxicity class, HOMO, LUMO and EPS plots were carried out to assess standard drug-likeliness properties of conjugates. Zone size inhibition of the conjugate, 4b (thymol+sulfadiazine) against MRSA and VRE strains on agar plates were 20 and 40μg/mL as the lowest MIC and MBC values, respectively; while the reference antibiotic ampicillin had the lowest MIC and MBC values at 80 to 180μg/mL. In vitro host-toxicity testing was carried out with cultured human-lymphocytes from umbilical cord blood, and 4b was broadly non-toxic to human cells at 15,000mg/L. Thus, 4b could be promoted a newer antibacterial, against gruesome MDR bacteria.

High frequency of vancomycin resistant Enterococcus faecalis in children: an alarming concern.

Enterococcus spp. is considered as important etiological agents of nosocomial infections. However, a little is known about the epidemiology of vancomycin resistant Enterococcus faecalis (VREF). The aim of this study was to investigate the frequency of VREF and detecting of two prevalent resistance genes (vanA, vanB) at Children Medical Center Hospital, an Iranian referral pediatric Hospital. During January 2013 to December 2013, 180 E. faecalis were isolated from clinical samples of hospitalized children. Antimicrobial testing was performed by Kirby-Bauer disk diffusion to gentamicin, amikacin, ceftriaxone, cefotaxime, ceftazidim, cefixime, piperacillin/tazobactam, cefepime, trimethoprim/sulfamethoxazole, erythromycin, clindamycin, linezolide and E-test method vancomycin and teicoplanin according to Clinical Laboratories Standards Institute (CLSI). Two prevalent resistance genes (vanA, vanB) were investigated in VREF isolates. Seventy-five (42%) of patients were male and 105 (58%) were female. Mean age of patients was 34.74 months. Cephalosporin resistance was found in majority of E. faecalis isolates (98.7 to ceftazidim, 95% to cefixime, 93.3% to ceftriaxone, and 89.4% to cefotaxime). Most of the isolated were susceptible to cefepime (91.7%). In addition, high level of erythromycin and clindamycin resistance was reported (93.4% and 91.2%). There were no linezolid-resistant E. faecalis among all isolates. Teicoplanin resistance was observed in 13.8% of E. faecalis (n = 25). Minimum Inhibitory concentration (MIC) ≥ 32 μg/ml for vancomycin was found in 29 isolates (16%) and vanA gene was detected in 21 (72%) VREF strains, while vanB gene was not detected in any of these isolates. The mortality rate of all cases was 3.4%. This study revealed high rate of vancomycin resistance in E. faecalis strains. Therefore, periodic surveillance of antibacterial susceptibilities is highly recommended to detect emerging resistance.

Comparative genome analysis of multiple vancomycin-resistant Enterococcus faecium isolated from two fatal cases

Enterococcus faecium is both a commensal of the human intestinal tract and an opportunistic pathogen. The increasing incidence of enterococcal infections is mainly due to the ability of this organism to develop resistance to multiple antibiotics, including vancomycin. The aim of this study was to perform comparative genome analyses on four vancomycin-resistant Enterococcus faecium (VREfm) strains isolated from two fatal cases in a tertiary hospital in Malaysia. Two sequence types, ST80 and ST203, were identified which belong to the clinically important clonal complex (CC) 17. This is the first report on the emergence of ST80 strains in Malaysia. Three of the studied strains (VREr5, VREr6, VREr7) were each isolated from different body sites of a single patient (patient Y) and had different PFGE patterns. While VREr6 and VREr7 were phenotypically and genotypically similar, the initial isolate, VREr5, was found to be more similar to VRE2 isolated from another patient (patient X), in terms of the genome contents, sequence types and phylogenomic relationship. Both the clinical records and genome sequence data suggested that patient Y was infected by multiple strains from different clones and the strain that infected patient Y could have derived from the same clone from patient X. These multidrug resistant strains harbored a number of virulence genes such as the epa locus and pilus-associated genes which could enhance their persistence. Apart from that, a homolog of E. faecalis bee locus was identified in VREr5 which might be involved in biofilm formation. Overall, our comparative genomic analyses had provided insight into the genetic relatedness, as well as the virulence potential, of the four clinical strains.

Bromomethylthioindole Inspired Carbazole Hybrids as Promising Class of Anti-MRSA Agents

Series of N-substituted carbazole analogues bearing an indole ring were synthesized as anti-methicillin-resistant Staphylococcus aureus (MRSA) agents from a molecular hybridization approach. The representative compound 19 showed an MIC = 1 μg/mL against a panel of MRSA clinical isolates as it possessed comparable in vitro activities to that of vancomycin. Moreover, compound 19 also exhibited MIC = 1 μg/mL activities against a recent identified Z172 MRSA strain (vancomycin-intermediate and daptomycin-nonsusceptible phenotype) and the vancomycin-resistant Enterococcus faecalis (VRE) strain. In a mouse model with lethal infection of MRSA (4N216), a 75% survival rate was observed after a single dose of compound 19 was intravenously administered at 20 mg/kg. In light of their equipotent activities against different MRSA isolates and VRE strain, the data underscore the importance of designed hybrid series for the development of new N-substituted carbazoles as potential anti-MRSA agents.

Multilevel population genetic analysis of vanA and vanB Enterococcus faecium causing nosocomial outbreaks in 27 countries (1986-2012).

Vancomycin-resistant Enterococcus faecium (VREfm) have been increasingly reported since the 1980s. Despite the high number of published studies about VRE epidemiology, the dynamics and evolvability of these microorganisms are still not fully understood. A multilevel population genetic analysis of VREfm outbreak strains since 1986, representing the first comprehensive characterization of plasmid content in E. faecium, was performed to provide a detailed view of potential transmissible units. From a comprehensive MeSH search, we identified VREfm strains causing hospital outbreaks (1986-2012). In total, 53 VanA and 18 VanB isolates (27 countries, 5 continents) were analysed and 82 vancomycin-susceptible E. faecium (VSEfm) were included for comparison. Clonal relatedness was established by PFGE and MLST (goeBURST/Bayesian Analysis of Population Structure, BAPS). Characterization of van transposons (PCR mapping, RFLP, sequencing), plasmids (transfer, ClaI-RFLP, PCR typing of relaxases, replication-initiation proteins and toxin-antitoxin systems, hybridization, sequencing), bacteriocins and virulence determinants (PCR, hybridization, sequencing) was performed. VREfm were mainly associated with major human lineages ST17, ST18 and ST78. VREfm and VSEfm harboured plasmids of different families [RCR, small theta plasmids, RepA_N (pRUM/pLG1) and Inc18] able to yield mosaic elements. Tn1546-vanA was mainly located on pRUM/Axe-Txe (USA) and Inc18-pIP186 (Europe) plasmids. The VanB2 type (Tn5382/Tn1549) was predominant among VanB strains (chromosome and plasmids). Both strains and plasmids contributed to the spread and persistence of vancomycin resistance among E. faecium. Horizontal gene transfer events among genetic elements from different clonal lineages (same or different species) result in chimeras with different stability and host range, complicating the surveillance of epidemic plasmids.

Fosfomycin Enhances the Activity of Daptomycin against Vancomycin-Resistant Enterococci in an In Vitro Pharmacokinetic-Pharmacodynamic Model.

Daptomycin (DAP) is being used more frequently to treat infections caused by vancomycin-resistant enterococcus (VRE). DAP tends to be less active against enterococci than staphylococci and may require high doses or combination therapy to be bactericidal. Fosfomycin (FOF) has activity against VRE and has demonstrated synergistic bactericidal activity with DAP in vitro The objective of this study was to evaluate the activity of DAP alone and in combination with FOF against VRE in an in vitro pharmacokinetic/pharmacodynamic (PK/PD) model. The activity of DAP at 8 and 12 mg/kg of body weight/day (DAP 8 and DAP 12, respectively) and FOF of 40 mg/kg intravenously every 8 h, alone and in combination, were evaluated against 2 vancomycin-resistant Enterococcus faecium strains (8019 and 5938) and 2 vancomycin-resistant E. faecalis strains (V583 and R7302) in an in vitro PK/PD model over 72 h. Cell surface charge in the presence and absence of FOF was evaluated by zeta potential analysis. Daptomycin-boron-dipyrromethene (bodipy) binding was assessed by fluorescence microscopy. The addition of FOF to DAP 8 and DAP 12 resulted in significantly increased killing over DAP alone at 72 h for 8019, V583, and R7302 (P < 0.05). Therapeutic enhancement was observed with DAP 12 plus FOF against 8019, V583, and R7302. Cell surface charge became more negative after exposure to FOF by ∼2 to 8mV in all 4 strains. Daptomycin-bodipy binding increased by 2.6 times in the presence of fosfomycin (P < 0.0001). The combination of DAP plus FOF may provide improved killing against VRE (including DAP-resistant strains) through modulation of cell surface charge. Further studies to clarify the role of intravenous FOF are warranted.

Neofiscalin A and fiscalin C are potential novel indole alkaloid alternatives for the treatment of multidrug-resistant Gram-positive bacterial infections.

Ten indole alkaloids were obtained from the marine sponge-associated fungus Neosartorya siamensis KUFA 0017. We studied the antimicrobial properties of these and of three other compounds previously isolated from the soil fungus N. siamensis KUFC 6349. Only neofiscalin A showed antimicrobial activity against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE); with a minimum inhibitory concentration (MIC) of 8 μg mL(-1) against both strains. Another compound, fiscalin C, presented synergistic activity against MRSA when combined with oxacillin, although alone showed no antibacterial effect. Moreover, neofiscalin A, when present at sub-MICs, hampered the ability of both MRSA and VRE strains to form a biofilm. Additionally, the biofilm inhibitory concentration values of neofiscalin A against the MRSA and VRE isolates were 96 and 80 μg mL(-1), respectively. At a concentration of 200 μg mL(-1), neofiscalin A was able to reduce the metabolic activity of the biofilms by ∼50%. One important fact is that our results also showed that neofiscalin A had no cytotoxicity against a human brain capillary endothelial cell line.

Susceptibility Pattern of Plasmid-borne Vancomycin-Resistant Enterococcus faecalis Strains to Selected Nigerian Medicinal Plants

Susceptibility Pattern of Plasmid-borne Vancomycin-Resistant Enterococcus faecalis Strains to Selected Nigerian Medicinal Plants

Prevalence of Diverse Clones of Vancomycin-Resistant Enterococcus faecium ST78 in a Chinese Hospital.

Vancomycin-resistant Enterococcus (VRE) has been identified in China. However, little is known about the spread of VRE isolates. The genetic relatedness of vancomycin-resistant Enterococcus faecium (VREfm) isolates was analyzed by pulsed-field gel electrophoresis (PFGE), their antimicrobial susceptibilities were analyzed by E-test and the VITEK 2 AST-GP67 test Kit, and their sequence types (STs) were investigated by multilocus sequence typing (MLST). S1-PFGE was used for plasmid profiling, and PCR and subsequent sequencing were performed to identify the virulence genes. A total of 96 nonduplicated VREfm isolates were obtained and categorized into 38 PFGE types (type 1-38). The predominant MLST type was ST78, while ST17, ST341, and ST342 were also sporadically identified. All types of clinical VREfm strains harbored the vanA gene; however, they carried plasmids of different sizes. While 92.1%, 71.1%, and 60.5% of VREfm strains carried hyl, scm, and ecbA genes, respectively, all of them were positive for esp, acm, sgrA, pilA, and pilB genes. Clonal VREfm spread was observed, and nonplasmid-mediated horizontal transfer of vancomycin-resistant gene might have conveyed resistance to some vancomycin-susceptible E. faecium strains. E. faecium ST78 carrying vanA gene was the most prevalent clone in this study. The high prevalence of virulence genes, including esp, hyl, acm, scm, ecbA, sgrA, pilA, and pilB, confirmed their important roles in the emergence of VREfm ST78 in nosocomial infections.

Change of antibiotic-resistant nosocomial microflora: Results of implementation of the strategy for control of antimicrobial treatment in multi speciality in-patient hospital

The unreasonable use of antimicrobial preparations is the one of leading causes of the increase of microbial resistance to antibiotics in in-patient departments. With the aim of containment of the resistance of nosocomial flora in multi-disciplinary in-patient hospital during two years there is used Antimicrobial Stewardship Program (ASP) with the involvement of a team of specialists in appropriate antibiotic therapy, protocols of perioperative antibiotic prophylaxis and empiric antibiotic therapy (EAT), educational programs for personal and measures for the assessment of the efficacy of ASP. The efficacy was evaluated with the use of such indices as the change of the pattern of nosocomial germs, incidence of methicillin-resistant Staphylococcus spp., vancomycin-resistant strains of Enterococcus faecium (VRE), incidence of extended-spectrum beta-lactamases(ESBL)-producing microorganisms, prevalence of carbapenem-resistant gram-negatives, drug resistance index (DRI). Implementation of ASP allowed to properly change the structure of nosocomial germs, to attain the real decline of the incidence of methicillinresistant Staphylococcus aureus (MRSA) from 16,2% (95%CI: 12-20,4) to 10,4% (95%CI: 7-13,8), p

Emergence of daptomycin non-susceptibility in colonizing vancomycin-resistant Enterococcus faecium isolates during daptomycin therapy

Infections due to vancomycin-resistant enterococci (VRE) are of significant importance in high-risk populations, and daptomycin is a bactericidal antibiotic to treat multidrug-resistant VRE in these patients. The emergence of daptomycin non-susceptibility invasive VRE during daptomycin therapy is a major clinical issue. Here the hypothesis was tested that systemic daptomycin therapy also induces the emergence of daptomycin non-susceptible (DNS-) isolates in colonizing VRE populations. 11 vancomycin-resistant Enterococcus faecium strain pairs recovered from rectal swabs were available for analysis. All initial isolates exhibited daptomycin MICs within the wild type MIC distribution of E. faecium (MIC≤4mg/L). In follow-up isolates from five patients a 4–16-fold daptomycin MIC increase was detected. All patients carrying DNS-VRE received daptomycin (14–28 days) at 4mg/kg body weight, while two patients in whom no DNS-VRE emerged were only treated with daptomycin for 1 and 4 days, respectively. Comparative whole genome sequencing identified DNS-VRE-specific single nucleotide polymorphisms (SNP), including mutations in cardiolipin synthase (Cls), and additional SNPs in independent genes potentially relevant for the DNS phenotype. Mutations within cls were also identified in three additional, colonizing DNS-VRE. Of these, at least one strain was transmitted within the hospital. In none of the VRE isolates tested, pre-existing or de novo mutations in the liaFSR operon were detected. This is the first report documenting the emergence of DNS-VRE in colonizing strains during daptomycin treatment, putting the patient at risk for subsequent DNS-VRE infections and priming the spread of DNS-VRE within the hospital environment.

Molecular characterization of vancomycin-resistant Enterococcus faecium strains isolated from carriage and clinical samples in a tertiary hospital, Turkey

This study aimed to determine the presence of vancomycin resistance (vanA and vanB) and virulence genes (esp, asa1, gelE, ace, hyl, cylA, cpd and ebpA) in vancomycin-resistant Enterococcus faecium (VREfm) strains and to analyse the clonal relationships among the strains. E. faecium strains were identified from rectal and clinical specimens by biochemical tests and the API-20 Strep kit. Susceptibility testing was performed using disc-diffusion and broth-dilution methods. PFGE was used for molecular typing of the VREfm strains. The vancomycin resistance and virulence genes were amplified by two-step multiplex PCR. All 55 VREfm isolates were resistant to penicillin G, ampicillin and high-level gentamicin but were susceptible to quinupristin/dalfopristin and linezolid. Multiplex PCR analysis indicated that all isolates harboured vanA and that 41 (75 %) were positive for virulence genes. The esp gene was the most common virulence factor and was detected in nine (41 %) invasive and 32 (96.7 %) non-invasive isolates. Multiple virulence genes were observed only in two non-invasive isolates; one harboured esp and ebpA and the other harboured esp, ebpA, asa1, gelE and cpd. PFGE typing yielded 16 different types, seven of which were clusters with two to 14 strains each. The clustering rates of the rectal swab, blood and urine isolates were 72.7 %, 61.5 % and 87.5 %, respectively. The genetic similarity observed among the VREfm isolates indicated cross-transmission in the hospital. Further studies on the virulence factors present in the strains might provide insight into the acquisition of these traits and their contribution to increased prevalence of VREfm.

Molecular characterization of resistance, virulence and clonality in vancomycin-resistant Enterococcus faecium and Enterococcus faecalis: A hospital-based study in Beijing, China

The incidence of vancomycin-resistant enterococcus (VRE) in China is increasing, the molecular epidemiology of VRE in China is only partly known. This study was conducted to assess the molecular characterization of resistance, virulence and clonality of 69 vancomycin-resistant Enterococcus faecium (VREfm) and seven vancomycin-resistant Enterococcus faecalis (VREfs) isolates obtained from a Chinese hospital between July 2011 and July 2013. The glycopeptide resistance genes (VanA and VanB) were screened by multiplex PCR. The presence of five putative virulence genes (esp, gelE, asa1, hyl and cylA) were evaluated by another multiplex PCR. Multilocus sequence typing (MLST) scheme was used to assess the clonality. All 76 VRE isolates exhibited VanA phenotype and harbored VanA gene. Esp was the only gene detected both in VREfm and VREfs strains, accounting for 89.9% and 42.9%, respectively. The hyl gene was merely positive in 27.5% of VREfm strains. MLST analysis demonstrated three STs (ST6, ST4 and ST470) in VREfs and twelve STs (ST78, ST571, ST17, ST564, ST389, ST18, ST547, ST341, ST414, ST343, ST262 and ST203) in VREfm, which were all designated as CC17 by eBURST algorithm. An outbreak of VREfm belonging to ST571 was found to happen within the neurology ward in this hospital. To our knowledge, this is the first report of ST6 (CC2) VREfs strains in China and the first outbreak report of VREfm strains belonging to ST571 around the world. Our data could offer important information for understanding the molecular features of VRE in China.

Anti-vancomycin-resistant Enterococcus faecium and E. faecalis activities of (-)-gossypol and derivatives from Thespesia garckeana

The root extract of Thespesia garckeana yielded three known oxidatively coupled sesquiterpenoids, namely (-)-gossypol (1) and two of its derivatives (-)-6-methoxygossypol (2) and (+)-6,6'-dimethoxygossypol (3), and the stem bark afforded (E)-docosyl-3-(3,4-dihydroxyphenyl) acrylate (4), stigmasterol (5) and betulinic acid (6). The structures of the isolated compounds were determined on the basis of full spectral data (1D and 2D NMR and HRMS) and comparison with literature values. Compound 1 showed potent antibacterial activity against vancomycin-resistant Enterococcus faecium (VRE) with IC50/MIC/MBC values of 1.71/4.82/19.31 µM, respectively, whereas the reference standard vancomycin was found to be inactive. The mono- and di-methoxylated derivatives of this compound, (-)-6-methoxygossypol (2) and (+)-6,6'-dimethoxygossypol (3), were less active with respective IC50/MIC/MBC values of 2.73/4.70/9.40 µM and 6.14/18.32/18.32 µM against this microbe. Compound 2 was more potent than 1 against the low level VRE strain with I50/MIC/MBC values of 4.34/9.40/9.40 µM (vs 5.23/19.31/19.3 µM for 1). This compound also showed interesting activities against Candida glabrata with an I50 value of 2.97 µM, but was less active against methicillin-resistant S. aureus (MRSA) exhibiting an IC50 value of 17.33 µM. Compound 1 demonstrated modest activity against the

Anti-Vancomycin-resistant Enterococcus faecium and E. faecalis Activities of (-)-Gossypol and Derivatives from Thespesia garckeana

The root extract of Thespesia garckeana yielded three known oxidatively coupled sesquiterpenoids, namely (-)-gossypol (1) and two of its derivatives (-)-6-methoxygossypol (2) and (+)-6,6′-dimethoxygossypol (3), and the stem bark afforded ( E)-docosyl-3-(3,4-dihydroxyphenyl) acrylate (4), stigmasterol (5) and betulinic acid (6). The structures of the isolated compounds were determined on the basis of full spectral data (1D and 2D NMR and HRMS) and comparison with literature values. Compound 1 showed potent antibacterial activity against vancomycin-resistant Enterococcus faecium (VRE) with IC50/MIC/MBC values of 1.71/4.82/19.31 μM, respectively, whereas the reference standard vancomycin was found to be inactive. The mono- and di-methoxylated derivatives of this compound, (-)-6-methoxygossypol (2) and (+)-6,6′-dimethoxygossypol (3), were less active with respective IC50/MIC/MBC values of 2.73/4.70/9.40 μM and 6.14/18.32/18.32 μM against this microbe. Compound 2 was more potent than 1 against the low level VRE strain with IC50/MIC/MBC values of 4.34/9.40/9.40 μM ( vs 5.23/19.31/19.31μM for 1). This compound also showed interesting activities against Candida glabrata with an IC50 value of 2.97 μM, but was less active against methicillin-resistant S. aureus (MRSA) exhibiting an IC50 value of 17.33 μM. Compound 1 demonstrated modest activity against the other microbes tested including C. glabrata, S. aureus and MRSA with IC50 values of 0.73, 9.15 and 8.99 μM, respectively.

Evaluation of the Prevalence of Insertion Element IS16 in Vancomycin-resistant Enterococci Strains of Enterococcus faecium Isolated From Transplantology Patients From a Warsaw Hospital Between 2010 and 2012

The study included 79 vancomycin-resistant Enterococcus faecium (VRE) strains isolated from 33 patients after kidney (n = 19) or liver (n = 14) transplantation; these patients were hospitalized between 2010 and 2012. The strains were obtained from infected persons as well as from carriers. All examined strains were tested for the susceptibility to antimicrobials active against enterococci and for the presence of vanA and vanB genes as well as the presence of the insertion sequence IS16 considered as one of the markers of hospital-associated strains. All 79 VRE strains of E faecium possessed IS16 and the vanA (vanB-negative) determinant. All tested strains were resistant to at least three groups of drugs; therefore, they were recognized as multidrug resistant. All isolates were resistant to glycopeptides, ampicillin, and most were resistant to tetracyclines, macrolides, nitrofurans, and high concentrations of aminoglycosides. The presence of insertion element IS16 and multiple resistance determinants prove that strains colonizing or infecting solid organ recipients were typical nosocomial pathogens.