Evolution and pathogenesis ofStaphylococcus aureus: lessons learned from genotyping and comparative genomics

Abstract

Staphylococcus aureus is an opportunistic pathogen and the major causative agent of numerous hospital- and community-acquired infections. Multilocus sequence typing reveals a highly clonal structure for S. aureus. Although infrequently occurring across clonal complexes, homologous recombination still contributed to the evolution of this species over the long term. agr-mediated bacterial interference has divided S. aureus into four groups, which are independent of clonality and provide another view on S. aureus evolution. Genome sequencing of nine S. aureus strains has helped identify a number of virulence factors, but the key determinants for infection are still unknown. Comparison of commensal and pathogenic strains shows no difference in diversity or clonal assignments. Thus, phage dynamics and global transcriptome shifts are considered to be responsible for the pathogenicity. Community-acquired methicillin-resistant S. aureus (C-MRSA) is characterized by a short SCCmec and the presence of a Panton-Valentine leukocidin locus, but no studies have proven their exact biologic roles in C-MRSA infection, indicating the existence of other mechanisms for the genesis of C-MRSA.

Clonal Complexes and Diversity of Exotoxin Gene Profiles in Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus Isolates from Patients in a Spanish Hospital

“…In addition, they may be eventually capable of breaking interlineage barriers. An important barrier is the SauI type I restriction-modification system, which appears to be one of the major mechanisms underlying the clonal structure of S. aureus (11,59). Nevertheless, a mobile genetic element can enter a CC from which it was originally excluded by means of a SauI restriction mutant.…”

“…As in the present study, a strong correlation between ST125 and spa type t067 was observed in both countries. Most of the remaining MRSA (12) CC5 (9), CC15, CC45 lukED (12), lukPV (2) tst (3), sea (7), seb (4), sec (10) eta (6), etb (11), etd (3) sed (12), sej (12), ser (10) (16) agrIII (16) CC5 (4), CC30 (11) lukED (16), lukPV (7) tst (15), sea (15), seb, sec (14) eta (6), etb (15) sed, sej seh (4) egc (4), egc-like (12) V2c (34) agrII ( isolates from the HUCA were also positive for SCCmec IV but belonged to other STs (i.e., ST5, ST228, or ST47); two carried SCCmec I and were of ST228, while one was not typeable by the applied method (60). The ST5-SCCmec IV (pediatric clone) (49) and ST228-SCCmec I (southern German clone) (48) clones are major hospital-acquired MRSA clones, widely distributed worldwide (7,46,56).…”

Pentaclethra macroloba tannins fractions active against methicillin-resistant staphylococcal and Gram-negative strains showing selective toxicity

“…In Brazil, methicillin-resistant Staphylococcus aureus (MRSA) is responsible for approximately 43% of these infections (Sader et al, 2004). Coagulase-negative staphylococci (CNS) is also recognized as a important nosocomial pathogen around the world, highlighting the multiresistant Staphylococcus epidermidis and Staphylococcus haemolyticus as the most isolated organisms from bacteremia (Nunes et al, 2007) and infections related to implanted medical devices (Uçkay et al, 2009) Resistance to methicillin is relevant in these pathogens because is related to resistance to other β-lactams and can be associated with resistance to other classes of antimicrobials (Feng et al, 2008).…”

In Silico Virulence and Resistance Profile Analysis of Staphylococcus species

“…al., 2012). Comparative genomics helps to improve knowledge on pathogenesis and drug resistance of microbial species (Feng et al, 2008).…”