Antimicrobial Resistance, Virulence Factors and Genetic Diversity of Escherichia coli Isolates from Household Water Supply in Dhaka, Bangladesh

Background: Unsafe water supplies continue to raise public health concerns, especially in urban areas in low resource countries. To understand the extent of public health risk attributed to supply water in Dhaka city, Bangladesh, Escherichia coli isolated from tap water samples collected from different locations of the city were characterized for their antibiotic resistance, pathogenic properties and genetic diversity. Methodology/Principal Findings: A total of 233 E. coli isolates obtained from 175 tap water samples were analysed for susceptibility to 16 different antibiotics and for the presence of genes associated with virulence and antibiotic resistance. Nearly 36% (n = 84) of the isolates were multi-drug(≥3 classes of antibiotics) resistant (MDR) and 26% (n = 22) of these were positive for extended spectrum β-lactamase (ESBL). Of the 22 ESBL-producers, 20 were positive for blaCTX-M-15, 7 for blaOXA-1-group(all had blaOXA-47) and 2 for blaCMY-2. Quinolone resistance genes, qnrS and qnrB were detected in 6 and 2 isolates, respectively. Around 7% (n = 16) of the isolates carried virulence gene(s) characteristic of pathogenic E. coli; 11 of these contained lt and/or st and thus belonged to enterotoxigenic E. coli and 5 contained bfp and eae and thus belonged to enteropathogenic E. coli. All MDR isolates carried multiple plasmids (2 to 8) of varying sizes ranging from 1.2 to >120 MDa. Ampicillin and ceftriaxone resistance were co-transferred in conjugative plasmids of 70 to 100 MDa in size, while ampicillin, trimethoprim-sulfamethoxazole and tetracycline resistance were co-transferred in conjugative plasmids of 50 to 90 MDa. Pulsed-field gel electrophoresis analysis revealed diverse genetic fingerprints of pathogenic isolates. Significance: Multi-drug resistant E. coli are wide spread in public water supply in Dhaka city, Bangladesh. Transmission of resistant bacteria and plasmids through supply water pose serious threats to public health in urban areas

Expression of Colonization Factor CS5 of Enterotoxigenic Escherichia coli (ETEC) Is Enhanced In Vivo and by the Bile Component Na Glycocholate Hydrate

Enterotoxigenic Escherichia coli (ETEC) is an important cause of acute watery diarrhoea in developing countries. Colonization factors (CFs) on the bacterial surface mediate adhesion to the small intestinal epithelium. Two of the most common CFs worldwide are coli surface antigens 5 and 6 (CS5, CS6). In this study we investigated the expression of CS5 and CS6 in vivo, and the effects of bile and sodium bicarbonate, present in the human gut, on the expression of CS5. Five CS5+CS6 ETEC isolates from adult Bangladeshi patients with acute diarrhoea were studied. The level of transcription from the CS5 operon was approximately 100-fold higher than from the CS6 operon in ETEC bacteria recovered directly from diarrhoeal stool without sub-culturing (in vivo). The glyco-conjugated primary bile salt sodium glycocholate hydrate (NaGCH) induced phenotypic expression of CS5 in a dose-dependent manner and caused a 100-fold up-regulation of CS5 mRNA levels; this is the first description of NaGCH as an enteropathogenic virulence inducer. The relative transcription levels from the CS5 and CS6 operons in the presence of bile or NaGCH in vitro were similar to those in vivo. Another bile salt, sodium deoxycholate (NaDC), previously reported to induce enteropathogenic virulence, also induced expression of CS5, whereas sodium bicarbonate did not

Patient satisfaction and clinical outcomes in implant‐supported overdentures retained by milled bars: Two‐year follow‐up

Objectives This observational clinical study evaluated the patient satisfaction and the clinical outcomes of edentulous arches rehabilitated with overdentures retained by CAD-CAM milled titanium bars. Materials and Methods Edentulous patients were treated with a full-arch removable overdenture anchored on two milled bars based on a friction retention system. Patient satisfaction was tested using the validated Oral Health Impact Profile (OHIP-14) questionnaire at the pre- and post-treatment visits, up to two years after prosthesis delivery (possible score range: 0-56. Best: 0). The prosthodontist satisfaction was also assessed through a designed questionnaire (best possible range 0-4. Best:0). Radiographic and clinical examinations were performed at baseline and after 2 years of function. Implant and prostheses complications were recorded. Results Forty (25 mandible) edentulous patients, mean age 69 +/- 9.5 (SD) (52% males, 10% smokers), were treated with a total of 185 implants. The mean difference between pre- and post-treatment OHIP-14 score was 20.6 +/- 8.0 (P < 0.0001) showing a high level of satisfaction for aesthetics, functional and psychological outcomes. This perception was not influenced by patient's age or gender. The clinicians' mean score was 3.4 +/- 4.0. There was a marginal bone level (MBL) gain of 0.02 +/- 0.22 mm between the two time points. Minor complications were reported in five patients. Conclusions This procedure may lead to satisfaction regarding aesthetics and mastication function. One of the most relevant aspects is the versatility, which allows selection of the most suitable treatment option according to patient needs. The prosthodontist satisfaction questionnaire showed that this procedure met the clinical expectations