Silico Comparative Analysis of Genes Encoding

Methicillin resistant S. aureus (MRSA) is becoming a primary public health consternation all over the world, besides much incremented with its morbidity and mortality among other pathogenic bacteria (Mogahid et al., 2015). Resistance of Staphylococci to methicillin and all β-lactam antibiotics is associated with the low affinity of a penicillin-binding protein (PBP), PBP2a, which is not present in susceptible staphylococci and is a foreign DNA origin encoded by mecA gene (Petinaki et al., 2001). mecA gene of staphylococcal chromosome also contains the genetic structures such as Tn554, pUB110, and pT181 that has resistance to non-β-lactam antibiotics. In the staphylococcal community, the prevalence of MRSA is predicted to be increased due to horizontal transfer of SCC mec genetic cassette.

S. aureus and S. pneumonia are leading causes of hospital and community acquired bacterial infection, and they have become a health threat at global level. However, many community-based infections are becoming more difficult to treat owing to the emergence of resistant organism such as multidrug-resistant S. pneumonia (MDRSP) and methicillin-resistant S. aureus (MRSA) (Van Bambeke et al., 2007; Stankovic et al., 2007). These two organisms are developing resistance to many of the β-lactam antibiotics (Chiu et al., 2007; Niederman, 2007). S. pneumoniae contains six PBPs, PBP1a, PBP1b, PBP2a, PBP2b, PBP2x and PBP3. β-lactam antibiotics resistance in S. pneumoniae is caused by alterations in the penicillin-binding domains of one or more of these six PBPs. Altered PBP1a, PBP2b and PBP2x are the most important PBPs for β-lactam antibiotic resistance (Asahi et al., 1999; Asahi and Ubukata, 1998; Smith and Klugman, 1995). MRSA acquires resistance to such antibiotics due to altered PBP2a that have low affinity for β-lactam antibiotics (Liu et al., 1990). Several studies revealed the mechanism of resistance of S. pneumoniae and MRSA to β-lactams using only a few cephaloporins and Carbapenems.

Staphylococcus species exists in skin microflora of various animals and responsible for common skin infections in domestic animals (Rich and Roberts, 2004). Staphylococcus aureus causes threatening invasive infections on mild skin and rapidly develop resistance to different antibiotics which are in medical use (Pantosti, 2012). Staphylococcus becoming more survival in the presence of semisynthetic penicillin like methicillin and oxacillin are said to be methicillin resistance. Methicillin resistance and their treatment is an unsettling condition, because of its resistance to beta-lactam antibiotics and also to a wide variety of antibiotics (Duquette and Nuttall, 2004). Molecular and metabolic protein interactions with extensive experimental supports are key sources for the drug designing studies. Among the protein interactions, proteins with proteins are the chief for finding the structural analogues as either drug targets or inhibitors. The in-silico identification of target residues is able with the involvement of protein-protein interaction networks, protein pathways and correspondingly strong literature with experimental evidences. Based on the extensive literature reviews the fundamental principles of protein interactions, such as Staphylococcus aureus, a gram positive bacteria contains the similar PBP protein complexes as that is present in a gram negative bacteria E. coli. Hence, Insilico comparative analysis of MecA gene coding penicillin binding proteins of Staphylococcus aureus has taken up about the E. coli divisome complex and its protein subsets as these organisms pertain identical complexed proteins as described below.