Community-acquired necrotizing pneumonia caused by methicillin-resistant Staphylococcus aureus ST30-SCCmecIVc-spat019-PVL positive in San Antonio de Areco, Argentina

Abstract

Community-acquired methicillin-resistant Staphylococcus aureus is the first cause of skin and soft tissue infections, but can also produce severe diseases such as bacteremia, osteomyelitis and necrotizing pneumonia. Some S. aureus lineages have been described in cases of necrotizing pneumonia worldwide, usually in young, previously healthy patients. In this work, we describe a fatal case of necrotizing pneumonia due to community-acquired methicillin-resistant S. aureus clone ST30-SCCmecIVc-spat019-PVL positive in an immunocompetent adult patient.

A Prospective Cohort Multicenter Study of Molecular Epidemiology and Phylogenomics of Staphylococcus aureus Bacteremia in Nine Latin American Countries

“…Apart from the Chilean/Cordobes clone, we were able to characterize an important proportion of isolates belonging to three different community-associated genetic lineages, ST30 carrying SCCmec IVc/E (30%), ST5 harboring SCCmec IVa (18%), and USA300-LV (SCCmec IVc/E [7%]) ( Fig. 1), consistent with previous local reports (15,17,18). In fact, Argentina was the only country in southern Latin America in which USA300-LV isolates were identified from bloodstream infections.…”

“…One of the most interesting findings of our study is that the proportion of MRSA strains remains high in the region but exhibits important regional variations. Indeed, rates of MRSA higher than 40% were found in the majority of countries, with the highest prevalence in the participating hospitals in Brazil (62%), a finding that is consistent with those of recently reported surveillance studies (11)(12)(13)(14)(15)(16)(17)(18)(19). A notable exception to the above appears to be in the included hospitals from both Colombia and Ecuador.…”

“…Of interest, some isolates belonging to ST72, ST88, and ST97 harbored some fragments of the COMER island, supporting the notion that the COMER element was mobile and might represent remnants of this DNA fragment, reinforcing the genetic relationship of strains in clade B. Finally, clade C grouped mostly Argentinian MRSA isolates with ST30 and SCCmec IVc/E, a finding previously reported for this country (15,17,18).…”

“…However, the most important genetic distinction between these two is the absence of the ACME island in USA300-LV, which is replaced by a gene cluster encoding proteins involved in the metabolism of copper and mercury (14). The results of our study, which are supported by several other local findings, indicate that in stark contrast with USA300, USA300-LV strains have been able to completely replace previously prevalent hospital-associated clones in Colombia and Ecuador (11)(12)(13)(14)(15)(16)(17)(18)(19). The reasons for such remarkable clonal switch in a relatively short time span are not known.…”

“…Our main objective was to understand the clinical and molecular characteristics of S. aureus bacteremia on a large scale. Although we understand that the hospitals enrolled may not represent the situation of other hospitals in the countries included in this study, it is important to note that our findings are supported by many previous local studies (11)(12)(13)(14)(15)(16)(17)(18)(19). Thus, our results may actually reflect an accurate picture of circulating S. aureus lineages causing bloodstream infections in the region.…”