Local Diversification of Methicillin- Resistant Staphylococcus aureus ST239 in South America After Its Rapid Worldwide Dissemination

Abstract

The global spread of specific clones of methicillin-resistant Staphylococcus aureus (MRSA) has become a major public health problem, and understanding the dynamics of geographical spread requires worldwide surveillance. Over the past 20 years, the ST239 lineage of MRSA has been recognized as an emerging clone across the globe, with detailed studies focusing on isolates from Europe and Asia. Less is known about this lineage in South America, and, particularly, Brazil where it was the predominant lineage of MRSA in the early 1990s to 2000s. To gain a better understanding about the introduction and spread of ST239 MRSA in Brazil we undertook a comparative phylogenomic analysis of ST239 genomes, adding seven completed, closed Brazilian genomes. Brazilian ST239 isolates grouped in a subtree with those from South American, and Western, romance-language-speaking, European countries, here designated the South American clade. After an initial worldwide radiation in the 1960s and 1970s, we estimate that ST239 began to spread in South America and Brazil in approximately 1988. This clone demonstrates specific genomic changes that are suggestive of local divergence and adaptational change including agrC single-nucleotide polymorphisms variants, and a distinct pattern of virulence-associated genes (mainly the presence of the chp and the absence of sea and sasX ). A survey of a geographically and chronologically diverse set of 100 Brazilian ST239 isolates identified this virulence genotype as the predominant pattern in Brazil, and uncovered an unexpectedly high prevalence of agr -dysfunction (30%). ST239 isolates from Brazil also appear to have undergone transposon (IS 25 6) insertions in or near global regulatory genes ( agr and mgr ) that likely led to rapid reprogramming of bacterial traits. In general, the overall pattern observed in phylogenomic analyses of ST239 is of a rapid initial global radiation, with subsequent local spread and adaptation in multiple different geographic locations. Most ST239 isolates harbor the ardA gene, which we show here to have in vivo anti-restriction activity. We hypothesize that this gene may have improved the ability of this lineage to acquire multiple resistance genes and distinct virulence-associated genes in each local context. The allopatric divergence pattern of ST239 also may suggest strong selective pressures for specific traits in different geographical locations.

Biofilm Formation by Staphylococcus aureus Clinical Isolates is Differentially Affected by Glucose and Sodium Chloride Supplemented Culture Media

“…Our results suggest that MRSA strains with SCC mec type III form strong biofilm in glucose and NaCl supplemented TSB, whereas SCC mec type I and II strains formed strong biofilms in the presence of glucose and differed when grown in NaCl supplemented TSB. The most prevalent hospital associated (HA) MRSA lineage that carries the SCC mec type III is MRSA-ST239 [55] and recognized as multidrug resistance across the globe [56]. In the present study, we found that 28.5% ( n = 6/21) of the MRSA strains tested were of the ST239 lineage (typically referred as HA strains), and of these, the ST5-SCC mec II and ST72 lineages predominated.…”

Different Modulatory Effects of Four Methicillin‐Resistant <em>Staphylococcus aureus</em> Clones on MG-63 Osteoblast-Like Cells

“…Very interestingly, despite the similar decrease in cell viability induced at 24 h by 5SA-ST5-II and 2SA-ST239-III, the latter demonstrated greater adaptability to the intracellular hostile environment, being the only one able to maintain its number during the entire period of infection. ST239 is a well-studied and widespread clone presenting some genomic characteristic features [49] as well as virulence gene content [50]. Some studies performed on bacteremic patients demonstrated the development of a non uniform and unique immune response directed to different staphylococcal proteins [51]; furthermore, a recent paper on MRSA ST239 identified a specific pattern of genes, confirming the differences among this clone and the others [52].…”

Methicillin-Resistant Staphylococcus aureus ST80 Clone: A Systematic Review

“…This clone disappeared and was replaced by the southern German clone (MRSA-ST228-I) and the New York/Japan epidemic clone (MRSA-ST5-II) between 2001 and 2004 [142]. Recent studies reported the local predominance of this clone in many countries including European countries [143,144], the Middle East, Asia, and South America [145]. Another epidemic clone, MRSA-ST22, has been predominately identified in recent years throughout the Middle East [44,45,[146][147][148][149][150][151][152][153][154], Europe [155][156][157][158][159][160], and Asia [161][162][163].…”