Emergence of vanA gene among vancomycin-resistant enterococci in a tertiary care hospital of North - East India

Background & objectives: Vancomycin-resistant enterococci (VRE) have become one of the most challenging nosocomial pathogens with the rapid spread of the multi-drug resistant strain with limited therapeutic options. It is a matter of concern due to its ability to transfer vancomycin resistant gene to other organisms. The present study was undertaken to determine the emergence of vancomycin-resistant enterococci and the vanA gene among the isolates in a tertiary care hospital of North-East India. Methods: A total of 67 consecutive enterococcal isolates from different clinical samples were collected and identified by using the standard methods. Antibiogram was done by disk diffusion method and VRE was screened by the disk diffusion and vancomycin supplement agar dilution method. The minimum inhibitory concentration (MIC) value for vancomycin was determined by E-test. The VRE isolates were analyzed by PCR for vanA gene. Results: A total of 54 (81%) Enterococcus faecalis and 13 (19%) E. faecium were detected among the clinical isolates and 16 (24%) were VRE. The VRE isolates were multidrug resistant and linezolid resistance was also found to be in three. MIC range to vancomycin was 16-32 µg/ml among the VRE. The vanA gene was found in nine of 16 VRE isolates. Interpretation & conclusions: Emergence of VRE and presence of vanA in a tertiary care hospital setting in North-East India indicate toward a need for implementing infection control policies and active surveillance

<span style="font-size:15.0pt;mso-bidi-font-size: 10.0pt;background:white;mso-bidi-font-weight:bold" lang="EN-GB">Prevalence and identification of extended spectrum β-lactamases (ESBL) in <i>Escherichia coli </i>isolated from a tertiary care hospital in North-East India </span>

108-114<span style="font-size:9.0pt;mso-bidi-font-size: 12.0pt" lang="EN-GB">Extended-spectrum β-lactamases (ESBLs) are rapidly evolving group of β-lactamase enzymes produced by the Gram negative bacteria. In this study, we determined the antimicrobial sensitivity pattern of <i style="mso-bidi-font-style: normal">Escherichia coli isolates and prevalence of TEM, SHV and CTX-M genes in ESBL positive E. coli isolated from the patients admitted to a tertiary care hospital in North-East India. A total of 85 multidrug-resistant isolates of E. coli obtained from clinical samples; urine (n=80), sputum (n=3), body fluid (n=1), vaginal discharge (n=1) were screened for resistance to third generation cephalosporins. ESBL production in resistant isolates was determined by double disk synergy test (DDST) and phenotypic confirmatory test (PCT). ESBL positive isolates were subjected to PCR for detection of TEM, SHV and CTX-M genes. Imipenem was found to be most effective against <i style="mso-bidi-font-style: normal">E. coli (susceptible isolates 96.47%) while ciprofloxacin was the least effective antibiotic (resistant isolates 60%). Among 33 ESBL positive isolates confirmed via PCT, preponderance in female population (60.6%) was noted. The most prevalent gene was blaSHV (63.04%) followed by blaTEM and blaCTX-M (60.86 and 54.34%, respectively) in ESBL positive E. coli. Most of the extensively used antibiotics, appear to be ineffective against the ever-mutating bacteria. This resistance urges cautious antimicrobial management on priority. Further, it helps in effectively designing the chemotherapeutic regimen for patients of a particular geographic area. </span

Novel mitochondria targeted copper(II) complexes of ferrocenyl terpyridine and anticancer active 8-hydroxyquinolines showing remarkable cytotoxicity, DNA and protein binding affinity

Metal complexes with organelle specificity and potent but selective cytotoxicity are highly desirable. In this work, we report the synthesis, characterization and cytotoxicity of six novel copper(II) complexes of the formula Cu(R-tpy)(N-O)]NO3 (1-6), where R-tpy is 4'-phenyl-2,2': 6', 2 `'-terpyridine (Ph-tpy; 1-3) or 4'-ferrocenyl-2,2': 6', 2 `'-terpyridine (Fc-tpy; 4-6), N-O is the anion of 8-hydroxyquinoline (HQ in 1, 4), 5-chloro-7-iodo-8-hydroxyquinoline (CQ in 2, 5) or 5-nitro-8-hydroxyquinoline (NQ in 3, 6). The complex Cu(Fc-tpy)(2)](ClO4)(2) (7) has also been prepared as a control and structurally characterized. The optimized geometries and the frontier orbitals of the complexes have been obtained from DFT calculations. The ferrocenyl appended complexes having the anticancer active CQ (in 5) and NQ (in 6) ligands show remarkable cytotoxicity, giving the respective IC50 values of 0.75 mu M and 0.52 mu M in HeLa and 1.3 mu M and 2.6 mu M in MCF-7 cancer cells. The phenyl appended complexes 2 and 3 are less active than their ferrocenyl analogues in both the cells while the complexes of HQ (in 1, 4) are the least active. Interestingly, complexes 4-6 are significantly less toxic to MCF-10A normal cells. The DCFDA, annexin-V-FITC and propidium iodide nuclear staining assays reveal an apoptotic mechanism of cell death which is attributable to the metal-assisted generation of reactive oxygen species. Imaging experiments on HeLa cells reveals that complex 5 accumulates primarily inside the mitochondria. The complexes bind to calf thymus DNA with moderate affinity giving K-b values in the range of 6.3 x 10(4)-7.4 x 10(4) M-1 and to HSA protein with significant affinity giving KHSA values in the range of 8.6 x 10(4)-1.3 x 10(5) M-1. Their affinity for DNA suggests that mitochondrial DNA could be the target while their affinity for HSA suggests that they could be transported by HSA in the blood. This work is the first report to show that the ferrocenyl appended copper(II) complexes of hydroxyquinoline ligands are remarkably cytotoxic to cancer cells but significantly less toxic to normal cells

Ferrocene conjugated copper(II) complexes of terpyridine and traditional Chinese medicine (TCM) anticancer ligands showing selective toxicity towards cancer cells

Six novel mixed-ligand copper(II) complexes, namely, Cu(R-tpy)(L)]NO3 (1-6), where R-tpy is 4-phenyl-2,2:6,2-terpyridine (Ph-tpy; 1-3) and 4-ferrocenyl-2,2:6,2-terpyridine (Fc-tpy; 4-6), L is the bidentate O,O donor monoanion of plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone; plum in 1, 4), chrysin (5,7-dihydroxyflavone; chry in 2, 5) and curcumin (bis(4-hydroxy-3-methoxyphenyl)-1,6-diene-3,5-dione; curc in 3, 6) have been synthesized and characterized and their in vitro cytotoxicity against cancer cells is evaluated. The energy optimized structures and the frontier orbitals of the complexes have been obtained from the DFT calculations. Complexes 4-6 with a conjugated ferrocenyl moiety and TCM anticancer ligands, namely, plum (in 4), chry (in 5) and curc (in 6) showed potent cytotoxicity giving respective IC50 values of 1.2M, 0.62M and 0.21M in HeLa and 2.0M and 1.0M and 0.34M in MCF-7 cancer cells while being much less toxic to MCF-10A normal cells (IC50: 8.3-17.1M). In contrast, complexes 1-3 with a conjugated phenyl moiety were appreciably less toxic to HeLa cells with respective IC50 values of 10.4M, 8.1M and 5.5M when compared with their ferrocenyl analogues 4-6. Mechanistic studies using Hoechst staining and Annexin-V-FITC assays on cancer cells revealed an apoptotic pathway of cell death induced by the complexes. Fluorescence imaging study showed that complex 6 having curcumin as ligand localized primarily in the mitochondria of HeLa cells. Thus, we demonstrate in this study that ferrocene conjugation to copper(II) complexes of TCM anticancer ligands significantly increases the selectivity and cytotoxicity of the resulting complexes towards cancer cells over normal cells