Insights into the Formations of Host-Guest Complexes Based on the Benzimidazolium Based Ionic Liquids-ß-Cyclodextrin Systems.

Inclusion complexation is one of the best strategies for developing a controlled release of a toxic drug without unexpected side effects from the very beginning of the administration to the target site. In this study, three benzimidazolium based ionic liquids (ILs) having bromide anion and cation bearing long alkyl chains, hexyl- ([C6CFBim]Br), octyl- ([C8CFBim]Br), and decyl- ([C10CFBim]Br) were designed and synthesized as antibacterial drugs. Inclusion complexes (ICs) of studied ILs have been prepared by the combination of ß-cyclodextrin (ß-CD), considering these conjugations should enhance the benignity of ILs and make them potential candidates for the controlled drug release. Characterizations and structural analysis of studied ICs have been performed by 1H NMR, 2D-ROESY NMR, FT-IR, HRMS, TGA, DSC, surface tension, ionic conductivity, dynamic light scattering (DLS), and isothermal titration calorimetry (ITC). Further, the morphology of the ICs has been analyzed by SEM and TEM. Furthermore, neat ILs and ICs have been treated against Escherichia coli and Bacillus subtilis to investigate their antibacterial activity, which confirms the prevention of bacterium growth and the shrinkage of the bacterial cell wall. The findings of this work provide the proof of concept that studied benzimidazolium based ILs-ß-CD host-guest complexes should act as a potential candidate in controlled drug delivery and other biomedical applications.

Virulence characteristics and molecular epidemiology of enteroaggregative Escherichia coli isolates from hospitalized diarrheal patients in Kolkata, India.

Enteroaggregative Escherichia coli (EAEC) is an important diarrheal enteropathogen defined by aggregative adherence to cultured epithelial cells. We have detected EAEC from 121 (6.6%) of 1,826 hospitalized patients admitted with diarrhea to the Infectious Diseases Hospital in Kolkata, India. Watery diarrhea was recorded significantly (P = 0.0142) more often in children. The majority of the EAEC isolates were not serotypeable (62%) and showed resistance to five or more antibiotics (76%). We studied different virulence genes and the molecular epidemiology of 121 EAEC isolates recovered from diarrheal patients. A PCR assay for detection of virulence genes, an assay for determination of clump formation in liquid culture, and a HeLa cell adherence assay were carried out to characterize the EAEC isolates. Investigations were also conducted to correlate the virulence gene profiles with diarrheal symptoms and molecular epidemiology by pulsed-field gel electrophoresis (PFGE). Two or more virulence genes were detected in 109 (90.1%) EAEC isolates. In the cluster analysis, some isolates with specific gene profiles and phenotypes formed a group or subcluster. This study highlights the comparative distributions of three fimbrial adhesins and other virulence genes among EAEC isolates. The diverse virulence gene and PFGE profiles, along with the existence of diverse serotypes and antibiograms, suggests that the EAEC isolates are genetically heterogeneous in Kolkata.

Molecular epidemiology of diarrhoeagenic Escherichia coli associated with sporadic cases and outbreaks of diarrhoea between 2000 and 2001 in India.

Diarrhoeal infection caused by Escherichia coli is common in India with occasional outbreaks. However, association of different pathotypes of diarrhoeagenic E. coli (DEC) with the disease and its phenotypic and genotypic characteristics are not fully demonstrated. In this study, E. coli strains from sporadic cases and outbreaks of diarrhoea during 2000-2001 were confirmed as DEC by polymerase chain reaction (PCR) targeting the specific virulence genes. DEC represented by enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC) and enteroaggregative E. coli (EAggEC) were mostly belonged to O serogroups 25, 86a, 114 and 146. The gene astA was frequently detected among ETEC and EAggEC than EPEC. After initial screening of 200 DEC strains with serology and antibiotic susceptibility test, 32 strains representing ETEC, EPEC, and EAggEC isolated from different areas of India were included in the pulsed-field gel electrophoresis (PFGE) analysis. Using the PFGE results, the hierarchical representation of different linkage levels between the DEC strains were determined by unweighed pair-group arithmetic mean (UPGAMA) method. Except for few strains, clonotyping by PFGE revealed no correlation between pathotypes and serogroups as well as the place of isolation of the DEC strains. The prevailing clonal diversity among the different categories of DEC strains suggests that the pathotypes of DEC belonged to diverse clones.

Clonal multidrug-resistant Shigella dysenteriae type 1 strains associated with epidemic and sporadic dysenteries in eastern India.

Multidrug-resistant strains of Shigella dysenteriae type 1 were implicated in three outbreaks and sporadic cases of dysentery in eastern India in 2002 and 2003. After a hiatus of 14 years, this pathogen reemerged with an altered antibiotic resistance pattern. In addition to ampicillin, co-trimoxazole, tetracycline, chloramphenicol, and nalidixic acid, all the recent strains were resistant to norfloxacin, lomefloxacin, pefloxacin, and ofloxacin and showed reduced susceptibility to ciprofloxacin. Pulsed-field gel electrophoresis identified a new clone of S. dysenteriae type 1 that was associated with the recent outbreaks and sporadic cases. Based on the spatial and temporal spread of multidrug-resistant S. dysenteriae type 1, we predict that this clonal type may spread further in this region.

Association of cytolethal distending toxin locus cdtB with enteropathogenic Escherichia coli isolated from patients with acute diarrhea in Calcutta, India.

Among Escherichia coli strains isolated from stool specimens from patients with acute diarrhea, 1.4% were found to harbor cdtB by use of enrichment cytolethal distending toxin (CDT) PCR. These isolates were identified as being enteropathogenic E. coli (EPEC). In a retrospective study using a probe hybridization assay, 6 of 138 EPEC strains were found to harbor the cdtB locus. cdtB-positive isolates mostly belong to the O86a and O127a serogroups, with the former being associated with higher expression of CDT. Pulsed-field gel electrophoresis profiles showed that the EPEC strains harboring cdtB strains are genetically diverse.