While S. marcescens is a rare cause of community-acquired infections, it has emerged as an important nosocomial healthcare-associated pathogen and a frequent source of outbreaks of hospital infection (72), in both adult (122) and paediatric patients (115).erratia marcescens is a member of the genus Serratia, which is a part of the family Enterobacteriaceae. Currently 14 species of Serratia are recognized within the genus, eight of which are associated with human infection (67).
The structure of nucleotide monomers. A nucleotide is made of a nucleobase (also termed a nitrogenous base), a five-carbon sugar (either ribose or 2-deoxyribose) depending on if it is DNA or RNA, and one or, depending on the definition, more than one phosphate groups.his nucleotide contains the five-carbon sugar deoxyribose, a nitrogenous base called adenine, and one phosphate group.
The Bases of DNA. The four nitrogen bases found in DNA are adenine, cytosine, guanine, and thymine. Each of these bases are often abbreviated a single letter: A (adenine), C (cytosine), G (guanine), T (thymine). The bases come in two categories: thymine and cytosine are pyrimidines, while adenine and guanine are purines (). The pyrimidine structure is produced by a six-membered, two-nitrogen molecule; purine refers to a nine-membered, four-nitrogen molecule.