The genetic feature and virulence determinant of highly virulent community-associated MRSA ST338-SCCmec Vb in China

Abstract

ST59 is the predominant pathotype of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in China. As a variant of ST59, there is relatively little known about the detailed information of ST338. To address this issue, here, we described thirteen ST338 CA-MRSA strains isolated from severe bloodstream infection cases, and focused on their epidemiology, genetic features and virulence potential. Phylogenetic analysis showed the earliest isolated strain of this study is likely a predecessor of recent ST338 lineage (after year of 2014). Furthermore, the phylogenetic reconstruction and time estimation suggested that ST338 evolved from ST59 in 1991. Notably, the carrying patten of virulence factors of all ST338 strains were similar, and the genomic islands νSaα, νSaγ and SaPI and the core virulence factors like hla and psm were detected in ST338 isolates. However, all ST338 isolates lacked some adhesion factors such as clfA, clfB, eap, cna and icaD. Additionally, among these ST338 strains, one PVL-negative ST338 isolate was detected. Experiment on mice nose and human alveolar epithelial cell showed that the nasal colonization ability of ST338 was weaker than that of CA-MRSA MW2. In a mouse bloodstream infection model and skin infection model, PVL+ and PVL− strains had the similar virulence, which was dependent on upregulation of toxin genes rather than the presence of mobile genetic elements such as ΦSa2 carrying PVL. Our findings provide important insight into the epidemiology and pathogenicity of the novel and highly virulent ST338-SCCmec Vb clone.

Genomic Epidemiology and Characterization of Methicillin-Resistant Staphylococcus aureus from Bloodstream Infections in China

“…The most prevalent were the Asian-Pacific clone ST59-SCC mec IV ( n = 231, 30.84%) and the New York/Japan ST5-SCC mec II clone ( n = 154, 20.56%), followed by the ST239-SCC mec III ( n = 54, 7.21%) clone and the Panton-Valentine leucocidin (PVL)-positive Taiwan clone ST59-SCC mec V ( n = 34, 4.54%). Based on detailed clinical information, 10 ST59 clones from Zhejiang Province and 13 ST338 clones ( 25 ) were confirmed as CA-MRSA, while 73 ST5 clones and 2 ST239 clones from Zhejiang Province were confirmed to be HA-MRSA isolates. However, due to a lack of available clinical records, other strains could not be identified as CA-MRSA or HA-MRSA.…”

“…Compared to types II and III, MRSA-IV and MRSA-V strains harbored smaller SCC mec elements ( 24 ). Previous study has demonstrated that smaller SCC mec cassettes may reduce the fitness burden ( 25 ). Therefore, the increase in ST59 MRSA-IV and MRSA-V clones may contribute to harboring a smaller SCC mec cassette, which lead to lower potential fitness burden.…”

Molecular Mechanisms of Drug Resistance in Staphylococcus aureus

“…More important CA-MRSA clones according to [ 2 , 23 , 217 , 218 , 219 , 220 , 221 , 222 , 223 , 224 , 225 , 226 , 227 , 228 , 229 , 230 , 231 , 232 ] are shown in Table 4 , most important HA-MRSA clones according to [ 23 , 85 , 125 , 220 , 224 , 233 , 234 , 235 , 236 ] are shown in Table 5 , and most important LA-MRSA clones according to [ 23 , 125 , 237 , 238 , 239 , 240 , 241 , 242 ] are shown in Table 6 .…”

Genomic Insights of First ermB-Positive ST338-SCCmecVT/CC59 Taiwan Clone of Community-Associated Methicillin-Resistant Staphylococcus aureus in Poland

“…The strain SO574/12 expresses a multidrug-resistance phenotype, highly similar to the previously described PM1 ST59-SCC mec V T /CC59 strain from Taiwan and the ZY05 ST338-SCC mec V T /CC59 strain from China [ 17 , 30 ]. Meanwhile, 13 ST338/CC59 strains among MRSA isolates obtained in China between 2014–2019, from human blood, were resistant only to erythromycin, clindamycin, and oxacillin [ 37 ]. The SO574/12 isolate is an older variant of ST338/CC59 CA-MRSA, but it appears more resistant than the more recent Chinese ones.…”

“…This may act as an excellent environment for the formation of ica ABCDR-dependent biofilm, a natural biological membrane. Due to the lack of the sdr D gene, the virulome of SO574/12 isolate (2012) shows similarity to ZY05 CA-MRSA (2016) but differs from the strains analyzed by Jin et al (2014–2019), which were described as negative in clf A, clf B, eap , cna , sdr C, sdr D, and ica D genes [ 37 ].…”