Aida Hamdan-Partida

By Samuel González-García, Aída Hamdan-Partida, Anaíd Bustos-Hamdan and Jaime Bustos-Martínez

Between 30 and 50% of the world population is permanently colonized in some anatomical site by Staphylococcus aureus, although the vast majority are asymptomatic carriers. The nose is its main niche and currently the colonization of S. aureus in the pharynx has become relevant due to the variety of reported carrier rates and the epidemiological importance of the dissemination of Methicillin-resistant S. aureus strains (MRSA) by pharyngeal carriers. For this bacterium to colonize a tissue successfully, it is necessary to establish many interactions with bacterial and host cell components such as bacterial wall teichoic acids (WTA) with the Scavenger SREC-1 host receptor and at the same time evade the defense mechanisms. On the other hand, there are host factors that will facilitate or complicate the colonization or persistence of S. aureus at these sites, such as physiological, genetic, immunological and microbiological factors.

Part of the book: Pharynx

By Samuel González-García, Aída Hamdan-Partida, Juan José Valdez-Alarcón, Anaid Bustos-Hamdan and Jaime Bustos-Martínez

Staphylococcus aureus is a microorganism that can colonize the nose, pharynx, and other regions of the body. It has also been observed that it can cause persistence. Successful colonization of S. aureus depends in the factors that favor the interaction of the bacteria with host cells. The bacterial determinants of S. aureus that have the capacity to adhere to human tissues involve adhesion factors such as teichoic acids and cell-wall-anchored proteins (CWA) such as ClfA, IcaA, SdrC, FnBPA, among others. The colonization and persistence process first involve adhesion to the tissue, followed by its reproduction and the possible formation of a biofilm. This review will describe the main virulence factors that allow bacterial adhesion and biofilm formation, including the accessory gene regulator genes (agr), related to colonization and persistence of S. aureus.

Part of the book: Staphylococcal Infections

By Anaid Bustos-Hamdan, Samuel González García, Juan Antonio Guzmán Salgado, Aída Hamdan-Partida and Jaime Bustos-Martínez

Staphylococcus aureus is one of the main bacteria that infect humans. The pediatric population is susceptible to this microorganism; in Mexico there are not enough epidemiological studies on this subject, so the objective of this work was to detect and typify S. aureus strains in an apparently healthy pediatric population of daycare centers and schools. Nasal and pharyngeal exudates were collected to determine the presence of these bacteria and typed as HA-MRSA or CA-MRSA strains by determining SCCmec, mecA gene, Panton-Valentine leucocidin (PVL), phenol-soluble modulin (psm), and spa-type. It was found that 62.55% of the population were carriers of S. aureus, with a higher percentage in the pharynx and in children older than 4 years of age. A total of 7.04% were carriers of MRSA strains, of which 14.64% were HA-MRSA strains and 85.36% were CA-MRSA strains. The strains showed resistance to several antibiotics. About 20% of the MRSA strains had PVL and psm genes. The strains presented a great variety of spa-types. A high number of S. aureus carriers were found in the pediatric population studied, with the presence of CA-MRSA strains, so surveillance and decolonization programs should be established.

Part of the book: Advances and Perspectives of Infections Caused by Staphylococcus aureus