Detection of qnr genes and gyrA mutation to quinolone phenotypic resistance of UTI pathogens in Bangladesh and the implications

Background: Plasmid-mediated quinolone-resistant (PMQR) genes and mutations within the quinolone resistance determining regions (QRDRs) resulted in the advent of quinolone-resistant pathogenic microbes. This research was designed to assess the roles of three PMQR genes, qnrA, qnrB, and qnrS, and any mutation in the gyrA gene in the QRDR as a process of quinolone/fluoroquinolone resistance to urinary tract infection (UTI) bacteria in Bangladesh to guide future management of UTIs. Methods: Pathogens from UTIs were isolated and identified, and their phenotype antibiotic susceptibilities were tested for lomefloxacin, ofloxacin, ciprofloxacin, and nalidixic acid. Polymerase chain reaction (PCR) detected the qnrA, qnrB, and qnrS genes. PCR and sequencing were performed to evaluate any mutation within the QRDRs of the gyrA gene. Results: Of 100 UTI bacteria, phenotypic resistance was observed in 95.0%, 89.0%, 83.0%, and 71.0% against lomefloxacin, nalidixic acid, ofloxacin, and ciprofloxacin, respectively. PMQR genes qnrS, qnrA, and qnrB genes were found in 54.0%, 1.0%, and 4.0% of isolates, respectively. Sequencing the gyrA gene revealed single mutation (Ser-83 to Leu) and double mutations (Ser-83 to Leu and Asp-87 to Asn). PMQR genes showed a statistically nonsignificant association with phenotypic resistance. Conclusions: This study confirms the presence of QRDR mutations that were independent of PMQR genes. Consequently, high resistance against quinolones among uropathogens is evident, and their future use needs to be moderated

Ligand-based modelling for screening natural compounds targeting Minichromosome Maintenance Complex Component-7 for potential anticancer effects

Minichromosome Maintenance Complex Component-7 (MCM7) plays a significant role in DNA replication. A comprehensive search of oncogenic databases (UALCAN and KMplot) revealed overexpression or upregulation of MCM7 in a number of cancers (including top prevalent cancer types worldwide). Thus, identification of novel compounds that can decrease expression level of MCM7 can act as a therapeutic strategy against the malignancies in which MCM7 is upregulated. In pursuit of this, computational drug discovery methodology was adopted to identify compounds which can antagonize MCM7 protein. At first, MCM7 protein was docked with control inhibitors of the protein such as Simvastatin, Atorvastatin, Lovastatin, Pravastatin and Breviscapine which showed binding affinity ranging from −8.6 to −7.5 kcal/mol. Ligand-based pharmacophore was generated based on these five compounds. Through ligand-based pharmacophore screening of 11,325 natural compounds, 68 hit compounds were identified. These compounds were docked against MCM7 protein unit. Furthermore, ADMET analysis has been performed to evaluate drug-like properties of all these 68 compounds. Among these, five compounds (Neoandrographolide, Pseudojervine, Isowighteone, Kushenol N and Bucharaine) showed promising ADMET properties and acceptable binding affinities, ranging from −7.7 kcal/mol to −9.3 kcal/mol. Molecular dynamics simulation was performed to evaluate interaction stability of the five compounds with MCM7 inside human body. For Neoandrographolide, Kushenol N and Bucharaine, each system was mostly stable after 15 ns of simulation. Taken together, these compounds can be further evaluated using appropriate cell-based and in vitro models to develop drugs targeting MCM7

Synthesis, in vitro bioassays, and computational study of heteroaryl nitazoxanide analogs

Abstract Antiprotozoal drug nitazoxanide (NTZ) has shown diverse pharmacological properties and has appeared in several clinical trials. Herein we present the synthesis, characterization, in vitro biological investigation, and in silico study of four hetero aryl amide analogs of NTZ. Among the synthesized molecules, compound 2 and compound 4 exhibited promising antibacterial activity against Escherichia coli (E. coli), superior to that displayed by the parent drug nitazoxanide as revealed from the in vitro antibacterial assay. Compound 2 displayed zone of inhibition of 20 mm, twice as large as the parent drug NTZ (10 mm) in their least concentration (12.5 µg/ml). Compound 1 also showed antibacterial effect similar to that of nitazoxanide. The analogs were also tested for in vitro cytotoxic activity by employing cell counting kit‐8 (CCK‐8) assay technique in HeLa cell line, and compound 2 was identified as a potential anticancer agent having IC50 value of 172 µg which proves it to be more potent than nitazoxanide (IC50 = 428 µg). Furthermore, the compounds were subjected to molecular docking study against various bacterial and cancer signaling proteins. The in vitro test results corroborated with the in silico docking study as compound 2 and compound 4 had comparatively stronger binding affinity against the proteins and showed a higher docking score than nitazoxanide toward human mitogen‐activated protein kinase (MAPK9) and fatty acid biosynthesis enzyme (FabH) of E. coli. Moreover, the docking study demonstrated dihydrofolate reductase (DHFR) and thymidylate synthase (TS) as probable new targets for nitazoxanide and its synthetic analogs. Overall, the study suggests that nitazoxanide and its analogs can be a potential lead compound in the drug development

Detection of qnr genes and gyrA mutation to quinolone phenotypic resistance of UTI pathogens in Bangladesh and the implications : resistance UTI pathogens Bangladesh

Background: Plasmid-mediated quinolone resistance (PMQR) genes and mutations within the quin-olone resistance-determining regions (QRDRs) bequeath to the advent of quinolone-resistant path-ogenic microbes. This research was designed to assess the roles of three PMQR genes, qnrA, qnrB, and qnrS, and any mutation in the gyrA gene in the QRDR region as a process of quino-lone/fluoroquinolone resistance to urinary tract infection (UTI) bacteria in Bangladesh to guide fu-ture management of UTIs. Methods: Pathogens from UTIs were isolated and identified, and their phenotype antibiotic susceptibilities were tested for lomefloxacin, ofloxacin, ciprofloxacin, and na-lidixic acid. Polymerase chain reaction (PCR) detected the qnrA, qnrB, and qnrS genes. PCR and se-quencing were performed to evaluate any mutation within the QRDRs of the gyrA gene. Results: Of 100 UTI bacteria, phenotypic resistance was observed in 95.0%, 89.0%, 83.0%, and 71.0% against lomefloxacin, nalidixic acid, ofloxacin, and ciprofloxacin, respectively. PMQR genes: qnrS, qnrA, and qnrB genes were found in 54.0%, 1.0%, and 4.0% of isolates, respectively. Sequencing the gyrA gene revealed single mutation (Ser-83 to Leu) and double mutations (Ser-83 to Leu and Asp-87 to Asn). PMQR genes showed a statistically non-significant association with phenotypic resistance. Conclu-sions: This study confirms the presence of QRDR mutations that were independent of PMQR quino-lone resistance genes. Consequently, high resistance against quinolones among uropathogens is ev-ident, and their future use needs to be moderated