Emergence of mcr-1 mediated colistin resistant Escherichia coli from a hospitalized patient in Bangladesh

Introduction: The emergence of plasmid mediated mcr in bacteria has become global public health threat. Herein, we report a mcr-1 positive E. coli in normal human flora from a patient admitted in Dhaka Medical College Hospital (DMCH). Methodology: In total, 700 non-duplicate rectal swabs were collected from DMCH during 13th May to 12th June 2018. E. coli from rectal swabs were isolated on chromogenic UTI media containing vancomycin 10mg/l (Liofilchem, Italy) and confirmed by MALDI-TOF. Minimum inhibitory concentrations (MIC) were determined by agar dilution and interpreted according to EUCAST breakpoints. Genomic analysis of mcr positive E. coli (MCRPEC) was performed by Illumina MiSeq sequencing and pulsed field gel electrophoresis (PFGE) using S1 nuclease DNA digests and blamcr-1 probing. Transferability of blamcr-1 were determined by conjugation assays. Results: We found one MCRPEC from 700 rectal swab screening which was isolated from the rectal swab culture of a 17-year boy who was admitted to the burns ICU, DMCH with 53% flame burn involving much of the trunk and face. Genome sequencing revealed that mcr-1 was present on an IncH12 plasmid of 257,243 bp and flanked by ISApaI1. The colistin resistance can be transferred to the recipient Klebsiella varricola with a frequency of 8.3 × 10-5. Transconjugants were more resistant to colistin than donor (MIC 32 µg/mL). Conclusions: This is the first human associated mcr in Bangladesh. These data indicate the need for a systematic “one health” surveillance in the country

Antimicrobial and catalytic applications of TiO2 nanoparticles prepared from titanium(IV)-Schiff base complexes as precursor

Attempts have been made to synthesis titanium dioxide (TiO2) nanoparticles using titanium (IV) complexes of Schiff base (TiOL) as a precursor where Schiff base ligand (L) act as a dibasic tetradentate one. TiO2 nanoparticles were synthesized by the direct calcination of titanium complexes at 500 °C for 3 hours. The analytical tools such as FT-IR, XRD, EDS, and SEM provided evidences in favor of the formation of TiO2 nanoparticles. Antimicrobial study showed that all prepared TiO2 nanoparticles have inhibition capacity on the growth against selected plant pathogenic fungi as well as some selected human pathogenic bacteria. Moreover, these TiO2 nanoparticles have catalytic capacity for the remarkable degradation (54.0%) of organic dye (Mordent brown 48) as well as industrial dye solutions