Occurrence and genetic characteristics of mcr-1-positive colistin-resistant E. coli from poultry environments in Bangladesh

ObjectivesColistin is one of the last-resort antibiotics for treatment of multi-drug resistant (MDR) Gram negative bacterial infections. We determined occurrence and characteristics of mcr-1-producing E. coli obtained from live bird markets (LBM), rural poultry farms (RPF) and rural household backyard poultry (HBP) in Bangladesh.MethodsWe tested 104 extended-spectrum β-lactamase (ESBL)-producing E. coli isolated during 2017-2018 from poultry sources for colistin resistance. We analyzed the resistant isolates for mcr gene and characterized mcr positive isolates for antibiotic susceptibility, antibiotic resistance genes, transmissible plasmids and clonal diversity.ResultsOf 104 isolates, 98 (94%) had MICcolistin ≥4 μg/mL and 14 (13.5%) were positive for mcr-1 of which 10 were from LBM (n = 10), 3 from RFP and 1 from HBP. All 14 mcr-1 E. coli were resistant to third generation cephalosporin and tetracycline, while 12 were resistant to fluoroquinolone and sulphamethoxazole, 10 were to aminoglycosides and 3 were to nitrofurantoin. Four isolates carried conjugative mcr-1 plasmid of 23 to 55 MDa in size. The 55 MDa plasmid found in 2 isolates carried additional resistant genes including blaCTX-M-group-1 and blaTEM-1 (ESBL), qnrB (fluoroquinolone) and rmtB (aminoglycoside). These plasmids belong to IncF family with additional replicons: HI1 and N. ERIC-PCR revealed a heterogeneous banding pattern of mcr-1 positive isolates.ConclusionWe report a 13.5% prevalence of mcr-1 positive MDR E. coli in poultry fecal samples predominantly from LBMs in Bangladesh accentuating the need for safe disposal of poultry feces and hygiene practices among people exposed to poultry.</div

Design, synthesis and molecular docking studies of 5-fluoro 1-aryl/alkyl sulfonyl benzimidazole derivatives for treatment of Parkinson’s disease

Novel sulfonyl derivatives of 5-fluoro-substituted benzimidazole were synthesized and characterized by 1H-NMR, 13C-NMR, 19F-NMR and mass spectrometry. Molecular docking study against monoamine oxidase B (MAO-B), responsible for Parkinson’s disease (PD), was performed. The binding energy and interactions with active amino acid residues in the binding site of newly synthesized derivatives, as well as conventional inhibitors (Selegiline and Rasagiline), were investigated and presented. According to the docking scores predicted by ADV (AutoDock vina) and AD (AutoDock), most of the synthesized derivatives have higher binding affinity toward MAO-B than the conventional inhibitors. This study shows that these fluoro-substituted benzimidazole derivatives can be developed into essential drugs for the treatment of PD. The antibacterial property of these compounds was investigated by disk diffusion test and minimum inhibitory concentration (MIC), against gram-negative and gram-positive bacteria. And the results were further verified by the bacteria kill test with respect to time. All the synthesized compounds demonstrated considerable antibacterial activity against both bacterial strains. Therefore, this work focuses on defining the efficiency of different types of sulfonyl derivatives of fluorinated benzimidazole in biomedical research for the treatment of PD highlighting their versatile biological properties.</p

DataSheet1_Systems and in vitro pharmacology profiling of diosgenin against breast cancer.ZIP

Aim: The purpose of this study was to establish a mode of action for diosgenin against breast cancer employing a range of system biology tools and to corroborate its results with experimental facts.Methodology: The diosgenin-regulated domains implicated in breast cancer were enriched in the Kyoto Encyclopedia of Genes and Genomes database to establish diosgenin-protein(s)-pathway(s) associations. Later, molecular docking and the lead complexes were considered for molecular dynamics simulations, MMPBSA, principal component, and dynamics cross-correlation matrix analysis using GROMACS v2021. Furthermore, survival analysis was carried out for the diosgenin-regulated proteins that were anticipated to be involved in breast cancer. For gene expression analyses, the top three targets with the highest binding affinity for diosgenin and tumor expression were examined. Furthermore, the effect of diosgenin on cell proliferation, cytotoxicity, and the partial Warburg effect was tested to validate the computational findings using functional outputs of the lead targets.Results: The protein-protein interaction had 57 edges, an average node degree of 5.43, and a p-value of 3.83e-14. Furthermore, enrichment analysis showed 36 KEGG pathways, 12 cellular components, 27 molecular functions, and 307 biological processes. In network analysis, three hub proteins were notably modulated: IGF1R, MDM2, and SRC, diosgenin with the highest binding affinity with IGF1R (binding energy −8.6 kcal/mol). Furthermore, during the 150 ns molecular dynamics (MD) projection run, diosgenin exhibited robust intermolecular interactions and had the least free binding energy with IGF1R (−35.143 kcal/mol) compared to MDM2 (−34.619 kcal/mol), and SRC (-17.944 kcal/mol). Diosgenin exhibited the highest cytotoxicity against MCF7 cell lines (IC50 12.05 ± 1.33) µg/ml. Furthermore, in H2O2-induced oxidative stress, the inhibitory constant (IC50 7.68 ± 0.51) µg/ml of diosgenin was lowest in MCF7 cell lines. However, the reversal of the Warburg effect by diosgenin seemed to be maximum in non-cancer Vero cell lines (EC50 15.27 ± 0.95) µg/ml compared to the rest. Furthermore, diosgenin inhibited cell proliferation in SKBR3 cell lines more though.Conclusion: The current study demonstrated that diosgenin impacts a series of signaling pathways, involved in the advancement of breast cancer, including FoxO, PI3K-Akt, p53, Ras, and MAPK signaling. Additionally, diosgenin established a persistent diosgenin-protein complex and had a significant binding affinity towards IGF1R, MDM2, and SRC. It is possible that this slowed down cell growth, countered the Warburg phenomenon, and showed the cytotoxicity towards breast cancer cells.</p

Demographic characteristics of children and mothers colonized with third-generation cephalosporin-resistant (3GCr) or fluoroquinolone-resistant (FQr) <i>E</i>. <i>coli</i> in areas with and without arsenic exposure through drinking water.

Demographic characteristics of children and mothers colonized with third-generation cephalosporin-resistant (3GCr) or fluoroquinolone-resistant (FQr) E. coli in areas with and without arsenic exposure through drinking water.</p

Co-occurrence of arsenic and antibiotic resistance in extended-spectrum β-lactamase (ESBL)-producing <i>E</i>. <i>coli</i> isolates.

Co-resistance to arsenic and antibiotic resistance of ESBL E. coli isolates in A) drinking water, B) mother stool, and C) child stool samples in Hajiganj (high arsenic exposure) and Matlab (low arsenic exposure) was determined by selecting bacterial isolates that showed resistance to any of the third-generation cephalosporin antibiotics (CRO, ceftriaxone, CTX, cefotaxime; CAZ, ceftazidime; FEP, cefepime) and were arsB gene positive by PCR assays. ‘n’ indicates the number of third-generation cephalosporin-resistant bacterial isolates for each group of samples. AMP, ampicillin; TE, tetracycline; CRO, ceftriaxone, CTX, cefotaxime; CAZ, ceftazidime; FEP, cefepime; CT, colistin; CIP, ciprofloxacin; NA, nalidixic acid; AZM, azithromycin; SXT, trimethoprim-sulfamethoxazole. The asterisks indicate significance (*p <0.05).</p

Prevalence of <i>arsB</i> gene among <i>E</i>. <i>coli</i> isolates.

Prevalence of E. coli isolates positive for arsB gene in A) total no. of E. coli isolates, B) third-generation cephalosporin-resistant E. coli isolates, and C) fluoroquinolone-resistant E. coli isolates obtained from water (WU), mother stool (MS), and child stool (CS) samples collected from the Hajiganj (RH, high arsenic exposure) and Matlab (RM, low arsenic exposure) areas in Bangladesh. Each bar represents the percentage of E. coli isolates that are positive for the arsB gene. The numbers on top of each bar indicate the number of E. coli isolates that are positive for the arsB gene and the numbers in parenthesis indicate the total number of E. coli isolates for each type of sample. The asterisks indicate significance (*p p p <0.001).</p

Forest plot for the odds ratios (OR) along with their 95% confidence intervals (CIs).

The black dot indicates the OR of being resistant to the corresponding antibiotics in the arsenic-resistant group of isolates compared to the arsenic-sensitive group of isolates. The whiskers are the spread of the CIs of the OR. The dotted line indicates the OR of 1 which implies no association. AMP, ampicillin; TE, tetracycline; CRO, ceftriaxone, CTX, cefotaxime; CAZ, ceftazidime; FEP, cefepime; CT, colistin; CIP, ciprofloxacin; NA, nalidixic acid; AZM, azithromycin; SXT, trimethoprim-sulfamethoxazole.</p

Neighbor-joining tree based on ribosomal MLST (rMLST) allele sequences for 30 <i>E</i>. <i>coli</i> isolates.

Sequence types (STs), ars operon, and minimum inhibitory concentration (MIC) to arsenite are shown next to the tree. Colored leaves and shaded regions indicate the phylogroups. RH and RM in isolate ID indicate if the isolate was obtained from Hajiganj (high arsenic exposure) or Matlab (low arsenic exposure) areas, respectively. WU, MS, and CS in isolate ID indicate isolates from drinking water, mother stool, and child stool, respectively.</p

Data set used to generate tables and figures.

(XLSX)</p

The abundance of total <i>E</i>. <i>coli</i> and antibiotic-resistant <i>E</i>. <i>coli</i> in water and stool samples from mothers and children in Hajiganj and Matlab.

The number of A) total E. coli, B) third-generation cephalosporin-resistant E. coli, and C) fluoroquinolone-resistant E. coli in drinking water (WU), mother stool (MS), and child stool (CS) samples collected from the Hajiganj (RH, high arsenic exposure) and Matlab (RM, low arsenic exposure) areas were counted from the plates for each of the samples as described in the Methods section. The numbers were calculated as either CFU/100ml for water samples or CFU/g for MS and CS samples and transformed to log10 count. Each box represents the first and third quartile number of E. coli (log10 transformed) for one type of sample with the black bars representing the median count and error bars representing the minimum and maximum range of the counts, respectively. The asterisks indicate significance (***p <0.001). ‘ns’ indicates not significant.</p