Assuntos
Antibacterianos , Colistina , Farmacorresistência Bacteriana , Metagenômica , Colistina/farmacologia , Humanos , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Recém-Nascido , Metagenômica/métodos , Microbioma Gastrointestinal/efeitos dos fármacos , Microbioma Gastrointestinal/genética , Proteínas de Escherichia coli/genética , Testes de Sensibilidade Microbiana , Escherichia coli/genética , Escherichia coli/efeitos dos fármacosRESUMO
New Delhi Metallo-ß-lactamase is an enzyme produced by gram-negative bacteria which has become one of the global concerns for physicians to treating the infection. These Metallo- ß-lactamase are capable of catalyzing the hydrolysis of almost all ß-lactam antibiotics, endangering infection treatment. Substitution of single or multiple amino acids results in new NDM variants. Forty NDM variants have been identified in different bacterial strains across the globe. In this review, we focused on the structural insight of all NDM variants including the type of amino acid residues and their position of substitution, country of origin, and type of bacteria carrying these resistant markers. We also discussed the carbapenemase activity and stability of enzymes that helps to design potent inhibitors to combat drug-resistant infections.
RESUMO
Seventeen polycyclic aromatic hydrocarbons (PAHs) were studied in surface waters (including particulate phase) from the Chenab River, Pakistan and ranged from 289-994 and 437-1290 ng l(-1) in summer and winter (2007-09), respectively. Concentrations for different ring-number PAHs followed the trend: 3-rings > 2-rings > 4-rings > 5-rings > 6-rings. The possible sources of PAHs are identified by calculating the indicative ratios; appropriating petrogenic sources of PAHs in urban and sub-urban regions with pyrogenic sources in agricultural region. Factor analysis based on principal component analysis identified the origins of PAHs from industrial activities, coal and trash burning in agricultural areas and municipal waste disposal from surrounding urban and sub-urban areas via open drains into the riverine ecosystem. Water quality guidelines and toxic equivalent factors highlighted the potential risk of low molecular weight PAHs to the aquatic life of the Chenab River. The flux estimated for PAHs contaminants from the Chenab River to the Indus River was >50 tons/year.
