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Biology subjects

Alhammadi, M. M.

Publications and source records attributed to Alhammadi, M. M..

2 recordsLinked to original sources

Antimicrobial resistance and comparative genome analysis of high-risk Escherichia coli clones isolated from Egyptian children with diarrhoea.

Escherichia coli is an important human pathogen that is able to cause a variety of infections, which can result in diarrhoea, urinary tract infections, sepsis, and even meningitis, depending on the pathotype of the infecting strain. Like many Gram-negative bacteria, E. coli is becoming increasingly resistant to many frontline antibiotics, including third generation cephalosporins and carbapenems, which are often considered the antibiotics of last resort for these infections. This is particularly the case in Egypt, where multidrug resistance (MDR) E. coli is highly prevalent. However, in spite of this, few Egyptian MDR E. coli strains have been fully characterised by genome sequencing. Here, we present the genome sequences of ten highly MDR E. coli strains, which were isolated from children, who presented with diarrhoea at the Outpatients Clinic of Assiut University Children's Hospital in Assiut, Egypt. We report that they carry multiple antimicrobial resistance genes, which includes extended spectrum {beta}-lactamase genes, as well as blaNDM and blaOXA carbapenemase genes, encoded on IncX3 and potentially IncF plasmids. Many of these stains were also found to be high-risk extra-intestinal pathogenic E. coli (ExPEC) clones, belonging to sequence types ST167, ST410 and ST617. Thus, their presence in the Egyptian paediatric population is particularly worrying, and this highlights the need for increased surveillance of high-priority pathogens in this part of the world.

genomics↗

Genome-wide binding of the cyclic AMP receptor protein in enteroaggregative Escherichia coli suggests a role in modulating virulence

Bacterial pathogens use a wide array of virulence factors to colonise and subsequently elicit disease in their host. These factors are often subject to extensive regulation at the transcriptional level, to ensure that their expression is timely. Although many pathogens use bespoke transcription factors that primarily target virulence genes, global transcription factors also sometimes play a role in controlling these genes. Enteroaggregative Escherichia coli (EAEC) is a significant cause of watery and mucoid diarrhoea globally. The organism colonises the small intestine before producing toxins that elicit disease, using a multitude of virulence factors that are encoded both chromosomally and on virulence plasmids. In this work, we have studied the cAMP Receptor Protein (CRP), a well-characterised bacterial global transcription factor, focusing on its role in pathogenicity of the prototype EAEC strain 042. We show that, although most functional CRP binding sites on the chromosome are conserved between E. coli K-12 and 042, CRP has been co-opted to couple the expression of some virulence genes to the nutritional state of the cell. We report novel mechanisms for CRP-dependent regulation of genes, whose products contribute to adhesion, production of a bacterial antibiotic, and export of a polysaccharide capsule.

microbiology↗