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Biology subjects

Miah, R.

Publications and source records attributed to Miah, R..

2 recordsLinked to original sources

Dirt floors and domestic animals are associated with soilborne exposure to antimicrobial resistant E. coli in rural Bangladeshi households

Soil can harbor enteropathogens and antimicrobial-resistant organisms in settings with domestic animals. We enrolled 49 households with young children (28 soil floors, 21 concrete floors) in Bangladesh and recorded animal ownership/management. Staff swabbed the floor of childrens sleeping area with a sterile sponge and collected floor dust and a child hand rinse. We used IDEXX QuantiTray/2000 with and without cefotaxime supplementation to enumerate cefotaxime-resistant and generic E. coli. There was 8.0 g/m2 of dust on soil floors vs. 0.2 g/m2 on concrete floors (p-value=0.005). We detected E. coli on 100% of soil vs. 86% of concrete floors and cefotaxime-resistant E. coli on 89% of soil vs. 43% of concrete floors (p-values<0.05). Cefotaxime-resistant E. coli prevalence on floors was 36% in compounds without animals, 79% in compounds with animals and 100% if animals stayed indoors overnight or the floor had animal feces; associations were strongest for chickens. In multivariable models, generic and cefotaxime-resistant E. coli counts were 1.5-2 log higher on soil vs. concrete floors, and counts on floors and child hands were 0.17-0.24 log higher for every 10 additional chickens owned (p-values<0.05). Efforts to mitigate infections and antimicrobial resistance in low-income countries should test flooring improvements and hygienic animal management. SynopsisIn rural Bangladeshi households, generic and cefotaxime-resistant E. coli were more common on soil floors than concrete floors and among households with higher cohabitation intensity with domestic animals, especially chickens.

microbiology↗

A programmable, selection-free CRISPR interference system in Staphylococcus aureus

Common dCas9-based CRISPR interference (CRISPRi) system for gene regulation requires antibiotic selection and exogenous inducer molecules, posing significant challenges when applied in in vivo bacterial infection models. Using Staphylococcus aureus as a model organism, we have developed a programmable, plasmid-based, but selection-free (ppsf)-CRISPRi system that is based on the pCM29- plasmid which is stable without antibiotic selection. In this ppsf-CRISPRi system, dCas9 expression is regulated by an endogenous virulence gene promoter, and sgRNA expression is driven by a constitutive promoter eliminating the need for exogenous inducer molecules. The system was programmed to silence the expression of genes encoding the virulence factor coagulase or peptidoglycan hydrolase autolysin, whenever their respective endogenous promoter was activated. The selection-free functionality was confirmed over at least 27 generations and verified by qPCR and phenotypic assays depending on the protein target, including coagulation of rabbit plasma and THP-1 macrophage cell infection in vitro as well as in vivo infection of Galleria mellonella larvae, in each case phenocopying the observations made using transposon mutant strains. The system is suitable for long-term studies of S. aureus pathogenesis in vitro or in vivo and represents a blueprint for the development of similar ppsf-CRISPRi systems in other bacterial species.

microbiology↗