Comparative RNA-seq-Based Transcriptome Analysis of the Virulence Characteristics of Methicillin-Resistant and -Susceptible Staphylococcus pseudintermedius Strains Isolated from Small Animals

Abstract

Staphylococcus pseudintermedius is often associated with pyoderma, which can turn into a life-threatening disease. The dissemination of highly resistant isolates has occurred in the last 10 years and has challenged antimicrobial treatment of these infections considerably. We have compared the carriage of virulence genes and biofilm formation between methicillin-resistant and methicillin-susceptible S. pseudintermedius (MRSP and MSSP, respectively) isolates and their in vitro gene expression profiles by transcriptome sequencing (RNA-seq). Isolates were relatively unevenly distributed among the four agr groups, and agr type III predominated in MRSP. Five virulence genes were detected in all isolates. Only the spsO gene was significantly associated with MSSP isolates (P ‫؍‬ 0.04). All isolates produced biofilm in brain heart infusion broth (BHIB)-4% NaCl. MSSP isolates produced more biofilm on BHIB and BHIB-1% glucose media than MRSP isolates (P ‫؍‬ 0.03 and P ‫؍‬ 0.02, respectively). Virulence genes encoding surface proteins and toxins (spsA, spsB, spsD, spsK, spsL, spsN, nucC, coa, and luk-I) and also prophage genes (encoding phage capsid protein, phage infection protein, two phage portal proteins, and a phage-like protein) were highly expressed in the MRSP isolate (compared with the MSSP isolate), suggesting they may play a role in the rapid and widespread dissemination of MRSP. This study indicates that MRSP may upregulate surface proteins, which may increase the adherence of MRSP isolates (especially sequence type 71 [ST71]) to corneocytes. MSSP isolates may have an increased ability to form biofilm under acidic circumstances, through upregulation of the entire arc operon. Complete understanding of S. pseudintermedius pathogenesis and host-pathogen signal interaction during infections is critical for the treatment and prevention of S. pseudintermedius infections. M ethicillin-resistant Staphylococcus pseudintermedius (MRSP)isolates have emerged as one of the leading causes of infectious diseases (including pyoderma, otitis and urinary tract infections) in companion animals, accounting for 20% to 47% of all clinical S. pseudintermedius isolates from dogs and cats (1). Moreover, some MRSP isolates are resistant to the antimicrobials regularly used for treatment (␤-lactams, fluoroquinolones, tetracyclines, lincosamides, and potentiated sulfonamides) in small animal practice (1, 2). The mecA gene, encoding resistance to ␤-lactams, has been acquired by several S. pseudintermedius clonal lineages on independent occasions; however, two clones, MRSP ST68-SCCmec V and MRSP ST71-SCCmec II-III, are the dominant ones and have spread globally (1, 3, 4). This dissemination was rapid, but the reasons for the fast emergence and success of these lineages are not fully understood (2). Genomic and proteomic studies conducted in the last few years are giving the first clues on the pathways by which MRSP isolates have become successful. A recent genomic report suggested that multidrug resistance evolved rapidly in MRSP due to the ...

Staphylococcal Protein A ( spa ) Locus Is a Hot Spot for Recombination and Horizontal Gene Transfer in Staphylococcus pseudintermedius

“…N, number of isolates; ST45_1, ST45 sublineage 1; ST45_2, ST45 sublineage 2. core virulence genes, however, can vary in different lineages, leading to lineage-wise differences in pathogenicity. The levels of expression of virulence genes are just as important as their lineage-specific presence (22). The frequencies of the remaining 17 virulence-associated genes varied across lineages, and they formed the basis of our virulence gene content analysis (Fig.…”

“…We compiled a list of 69 virulence-associated genes from S. pseudintermedius and other Staphylococcus species (Table S2). This included genes involved in host adaptation, attachment and invasion, host cell lysis, immune evasion, biofilm formation, and regulation of the expression of genes involved in virulence (17,21,22,26,31,32,34,55,(60)(61)(62). The presence of these genes in the genome assemblies of 622 strains was determined using large-scale BLAST score ratio (LS-BSR) with the blastn option (63).…”

Exploring Listeria monocytogenes Transcriptomes in Correlation with Divergence of Lineages and Virulence as Measured in Galleria mellonella

“…scription of some bacterial pathogens could be informative of their virulence level. For example, transcriptional profiling of methicillin-resistant and -susceptible cultures of Staphylococcus pseudintermedius identified differentially expressed genes such as surface proteins, toxins, and prophage genes that might contribute to virulence (42). In the current study, we produced a comprehensive transcriptome data set from which basal transcription patterns were analyzed in multiple aspects putatively associated with virulence potential.…”

“…Importantly, several studies reported differential expression of conserved genes between pathogenic versus nonpathogenic isolates (40)(41)(42)(43) which could reflect the contribution of the regulatory network to fine-tuning gene expression of virulent isolates immediately after ingestion and in the gastrointestinal tract, therefore maximizing their fitness in the host system (44). However, as most studies were restricted to a limited number of strains, the weight of intraspecific diversity tended to be overlooked.…”

Virulence factors in coagulase-positive staphylococci of veterinary interest other than Staphylococcus aureus

“…Comparisons have also been made between Methicillin-susceptible (MSSP) and Methicillin-resistant S. pseudintermedius (MRSP) in order to determine if their virulence factor profiles are different. In another study (Couto et al 2016), twenty one MRSP and twenty one MSSP, obtained from 18 asymptomatic carriers and 24 diseased dogs and cats were included. MRSP seemed to upregulate surface proteins, increasing the adherence of isolates to keratinocytes.…”