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

mSphere ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Alem Zukancic ◽  
Mubin A. Khan ◽  
Sumayya J. Gurmen ◽  
Quinn M. Gliniecki ◽  
Dayna L. Moritz-Kinkade ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Genetic Factors ◽  
Hot Spot ◽  
Protein A ◽  
Multidrug Resistant ◽  
Staphylococcal Protein A ◽  
Staphylococcus Pseudintermedius ◽  
Content Type ◽  
Staphylococcal Protein

ABSTRACT Staphylococcus pseudintermedius is a major canine pathogen but also occasionally colonizes and infects humans. Multidrug-resistant methicillin-resistant S. pseudintermedius (MDR MRSP) strains have emerged globally, making treatment and control of this pathogen challenging. Sequence type 71 (ST71), ST68, and ST45 are the most widespread and successful MDR MRSP clones. The potential genetic factors underlying the clonal success of these and other predominant clones remain unknown. Characterization of the pangenome, lineage-associated accessory genes, and genes acquired through horizontal gene transfer from other bacteria is important for identifying such factors. Here, we analyzed genome sequence data from 622 S. pseudintermedius isolates to investigate the evolution of pathogenicity across lineages. We show that the predominant clones carry one or more lineage-associated virulence genes. The gene encoding staphylococcal protein A (SpA), a key virulence factor involved in immune evasion and a potential vaccine antigen, is deleted in 62% of isolates. Most importantly, we have discovered that the spa locus is a hot spot for recombination and horizontal gene transfer in S. pseudintermedius, where genes related to restriction modification, prophage immunity, mercury resistance, and nucleotide and carbohydrate metabolism have been acquired in different lineages. Our study also establishes that ST45 is composed of two distinct sublineages that differ in their accessory gene content and virulence potential. Collectively, this study reports several previously undetected lineage-associated genetic factors that may have a role in the clonal success of the major MDR MRSP clones. These data provide a framework for future experimental studies on S. pseudintermedius pathogenesis and for developing novel therapeutics against this pathogen. IMPORTANCE Staphylococcus pseudintermedius is a major canine pathogen but can also occasionally infect humans. Identification of genetic factors contributing to the virulence and clonal success of multidrug-resistant S. pseudintermedius clones is critical for the development of therapeutics against this pathogen. Here, we characterized the genome sequences of a global collection of 622 S. pseudintermedius isolates. We show that all major clones, besides carrying core virulence genes, which are present in all strains, carry one or more lineage-specific genes. Many of these genes have been acquired from other bacterial species through a horizontal gene transfer mechanism. Importantly, we have discovered that the staphylococcal protein A gene (spa), a widely used marker for molecular typing of S. pseudintermedius strains and a potential vaccine candidate antigen, is deleted in 62% of strains. Furthermore, the spa locus in S. pseudintermedius acts as a reservoir to accumulate lineage-associated genes with adaptive functions.

scholarly journals Peptidoglycan Contribution to the B Cell Superantigen Activity of Staphylococcal Protein A

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Miaomiao Shi ◽  
Stephanie E. Willing ◽  
Hwan Keun Kim ◽  
Olaf Schneewind ◽  
Dominique Missiakas
Keyword(s):  
B Cell ◽  
Protein A ◽  
B Cell Receptors ◽  
Staphylococcal Protein A ◽  
Content Type ◽  
Cell Receptors ◽  
Staphylococcal Protein ◽  
Lpxtg Motif ◽  
Sorting Signal ◽  
Lysm Domain

ABSTRACT Staphylococcus aureus causes reiterative and chronic persistent infections. This can be explained by the formidable ability of this pathogen to escape immune surveillance mechanisms. Cells of S. aureus display the abundant staphylococcal protein A (SpA). SpA binds to immunoglobulin (Ig) molecules and coats the bacterial surface to prevent phagocytic uptake. SpA also binds and cross-links variable heavy 3 (VH3) idiotype (IgM) B cell receptors, promoting B cell expansion and the secretion of nonspecific VH3-IgM via a mechanism requiring CD4+ T cell help. SpA binding to antibodies is mediated by the N-terminal Ig-binding domains (IgBDs). The so-called region X, uncharacterized LysM domain, and C-terminal LPXTG sorting signal for peptidoglycan attachment complete the linear structure of the protein. Here, we report that both the LysM domain and the LPXTG motif sorting signal are required for the B cell superantigen activity of SpA in a mouse model of infection. SpA molecules purified from staphylococcal cultures are sufficient to exert B cell superantigen activity and promote immunoglobulin secretion as long as they carry intact LysM and LPXTG motif domains with bound peptidoglycan fragments. The LysM domain binds the glycan chains of peptidoglycan fragments, whereas the LPXTG motif is covalently linked to wall peptides lacking glycan. These findings emphasize the complexity of SpA interactions with B cell receptors. IMPORTANCE The LysM domain is found in all kingdoms of life. While their function in mammals is not known, LysM domains of bacteria and their phage parasites are associated with enzymes that cleave or remodel peptidoglycan. Plants recognize microbe-associated molecular patterns such as chitin via receptors endowed with LysM-containing ectodomains. In plants, such receptors play equally important roles in defense and symbiosis signaling. SpA of S. aureus carries a LysM domain that binds glycan strands of peptidoglycan to influence defined B cell responses that divert pathogen-specific adaptive immune responses.

scholarly journals Prophage-Mediated Disruption of Genetic Competence in Staphylococcus pseudintermedius

mSystems ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Michael R. Brooks ◽  
Lyan Padilla-Vélez ◽  
Tarannum A. Khan ◽  
Azaan A. Qureshi ◽  
Jason B. Pieper ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Gene Transfer ◽  
North America ◽  
Horizontal Gene Transfer ◽  
Antibiotic Resistance Genes ◽  
Genomic Analysis ◽  
Fluoroquinolone Resistance ◽  
Genetic Competence ◽  
Staphylococcus Pseudintermedius ◽  
Content Type

ABSTRACT Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is a major cause of soft tissue infections in dogs and occasionally infects humans. Hypervirulent multidrug-resistant (MDR) MRSP clones have emerged globally. The sequence types ST71 and ST68, the major epidemic clones of Europe and North America, respectively, have spread to other regions. The genetic factors underlying the success of these clones have not been investigated thoroughly. Here, we performed a comprehensive genomic analysis of 371 S. pseudintermedius isolates to dissect the differences between major clonal lineages. We show that the prevalence of genes associated with antibiotic resistance, virulence, prophages, restriction-modification (RM), and CRISPR/Cas systems differs significantly among MRSP clones. The isolates with GyrA+GrlA mutations, conferring fluoroquinolone resistance, carry more of these genes than those without GyrA+GrlA mutations. ST71 and ST68 clones carry lineage-specific prophages with genes that are likely associated with their increased fitness and virulence. We have discovered that a prophage, SpST71A, is inserted within the comGA gene of the late competence operon comG in the ST71 lineage. A functional comG is essential for natural genetic competence, which is one of the major modes of horizontal gene transfer (HGT) in bacteria. The RM and CRISPR/Cas systems, both major genetic barriers to HGT, are also lineage specific. Clones harboring CRISPR/Cas or a prophage-disrupted comG exhibited less genetic diversity and lower rates of recombination than clones lacking these systems. After Listeria monocytogenes, this is the second example of prophage-mediated competence disruption reported in any bacteria. These findings are important for understanding the evolution and clonal expansion of MDR MRSP clones. IMPORTANCE Staphylococcus pseudintermedius is a bacterium responsible for clinically important infections in dogs and can infect humans. In this study, we performed genomic analysis of 371 S. pseudintermedius isolates to understand the evolution of antibiotic resistance and virulence in this organism. The analysis covered significant reported clones, including ST71 and ST68, the major epidemic clones of Europe and North America, respectively. We show that the prevalence of genes associated with antibiotic resistance, virulence, prophages, and horizontal gene transfer differs among clones. ST71 and ST68 carry prophages with novel virulence and antibiotic resistance genes. Importantly, site-specific integration of a prophage, SpST71A, has led to the disruption of the genetic competence operon comG in ST71 clone. A functional comG is essential for the natural uptake of foreign DNA and thus plays an important role in the evolution of bacteria. This study provides insight into the emergence and evolution of antibiotic resistance and virulence in S. pseudintermedius, which may help in efforts to combat this pathogen.

scholarly journals Fluorescence-Based Detection of Natural Transformation in Drug-ResistantAcinetobacter baumannii

2018 ◽  
Vol 200 (19) ◽  
Author(s):  
Anne-Sophie Godeux ◽  
Agnese Lupo ◽  
Marisa Haenni ◽  
Simon Guette-Marquet ◽  
Gottfried Wilharm ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Antibiotic Resistance ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Natural Transformation ◽  
Multidrug Resistant ◽  
New Method ◽  
Content Type ◽  
Transfer Mechanisms ◽  
Multiple Antibiotics

ABSTRACTAcinetobacter baumanniiis a nosocomial agent with a high propensity for developing resistance to antibiotics. This ability relies on horizontal gene transfer mechanisms occurring in theAcinetobactergenus, including natural transformation. To study natural transformation in bacteria, the most prevalent method uses selection for the acquisition of an antibiotic resistance marker in a target chromosomal locus by the recipient cell. Most clinical isolates ofA. baumanniiare resistant to multiple antibiotics, limiting the use of such selection-based methods. Here, we report the development of a phenotypic and selection-free method based on flow cytometry to detect transformation events in multidrug-resistant (MDR) clinicalA. baumanniiisolates. To this end, we engineered a translational fusion between the abundant and conservedA. baumanniinucleoprotein (HU) and the superfolder green fluorescent protein (sfGFP). The new method was benchmarked against the conventional antibiotic selection-based method. Using this new method, we investigated several parameters affecting transformation efficiencies and identified conditions of transformability one hundred times higher than those previously reported. Using optimized transformation conditions, we probed natural transformation in a set of MDR clinical and nonclinical animalA. baumanniiisolates. Regardless of their origin, the majority of the isolates displayed natural transformability, indicative of a conserved trait in the species. Overall, this new method and optimized protocol will greatly facilitate the study of natural transformation in the opportunistic pathogenA. baumannii.IMPORTANCEAntibiotic resistance is a pressing global health concern with the rise of multiple and panresistant pathogens. The rapid and unfailing resistance to multiple antibiotics of the nosocomial agentAcinetobacter baumannii, notably to carbapenems, prompt to understand the mechanisms behind acquisition of new antibiotic resistance genes. Natural transformation, one of the horizontal gene transfer mechanisms in bacteria, was only recently described inA. baumanniiand could explain its ability to acquire resistance genes. We developed a reliable method to probe and study natural transformation mechanism inA. baumannii. More broadly, this new method based on flow cytometry will allow experimental detection and quantification of horizontal gene transfer events in multidrug-resistantA. baumannii.

scholarly journals Direct Repeat Unit (dru) Typing of Methicillin-Resistant Staphylococcus pseudintermedius from Dogs and Cats

2015 ◽  
Vol 53 (12) ◽  
pp. 3760-3765 ◽  
Author(s):  
Kristina Kadlec ◽  
Stefan Schwarz ◽  
Richard V. Goering ◽  
J. Scott Weese
Keyword(s):  
North America ◽  
Repeat Unit ◽  
Protein A ◽  
Direct Repeat ◽  
Staphylococcal Protein A ◽  
Convenience Sample ◽  
Staphylococcus Pseudintermedius ◽  
Methicillin Resistant ◽  
Content Type ◽  
Cost Efficient

Methicillin-resistantStaphylococcus pseudintermedius(MRSP) has emerged in a remarkable manner as an important problem in dogs and cats. However, limited molecular epidemiological information is available. The aims of this study were to apply direct repeat unit (dru) typing in a large collection of well-characterized MRSP isolates and to usedrutyping to analyze a collection of previously uncharacterized MRSP isolates. Two collections of MRSP isolates from dogs and cats were included in this study. The first collection comprised 115 well-characterized MRSP isolates from North America and Europe. The data for these isolates included multilocus sequence typing (MLST) and staphylococcal protein A gene (spa)typing results as well as SmaI macrorestriction patterns after pulsed-field gel electrophoresis (PFGE). The second collection was a convenience sample of 360 isolates from North America. Thedruregion was amplified by PCR, sequenced, and analyzed. For the first collection, the discriminatory indices of the typing methods were calculated. All isolates were successfullydrutyped. The discriminatory power fordrutyping (D= 0.423) was comparable to that ofspatyping (D= 0.445) and of MLST (D= 0.417) in the first collection. Occasionally,drutyping was able to further discriminate between isolates that shared the samespatype. Among all 475 isolates, 26 differentdrutypes were identified, with 2 predominant types (dt9a and dt11a) among 349 (73.4%) isolates. The results of this study underline thatdrutyping is a useful tool for MRSP typing, being an objective, standardized, sequence-based method that is relatively cost-efficient and easy to perform.

scholarly journals Staphylococcal Protein A Induces Leukocyte Necrosis by Complexing with Human Immunoglobulins

mBio ◽  
2021 ◽  
Author(s):  
Proinnsias G. Fox ◽  
Francesca Schiavetti ◽  
Rino Rappuoli ◽  
Rachel M. McLoughlin ◽  
Fabio Bagnoli
Keyword(s):  
Staphylococcus Aureus ◽  
Protein A ◽  
The United States ◽  
Staphylococcal Protein A ◽  
Human Pathogen ◽  
Content Type ◽  
Staphylococcal Protein ◽  
Human Immunoglobulins ◽  
Human Immune Response ◽  
Human Immune

Staphylococcus aureus is one of the largest health care threats faced by humankind, with a reported mortality rate within the United States greater than that of HIV/AIDS, tuberculosis, and viral hepatitis combined. One of the defining features of S. aureus as a human pathogen is its ability to evade and impair the human immune response through expression of staphylococcal protein A.

scholarly journals Staphylococcal Protein A Contributes to Persistent Colonization of Mice withStaphylococcus aureus

2018 ◽  
Vol 200 (9) ◽  
Author(s):  
Yan Sun ◽  
Carla Emolo ◽  
Silva Holtfreter ◽  
Siouxsie Wiles ◽  
Barry Kreiswirth ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
B Cell ◽  
Neutralizing Antibodies ◽  
Protein A ◽  
Staphylococcal Protein A ◽  
Content Type ◽  
Staphylococcal Protein ◽  
Host Immune Responses ◽  
Increased Risk ◽  
Drug Resistant Strains

ABSTRACTStaphylococcus aureuspersistently colonizes the nasopharynx in humans, which increases the risk for invasive diseases, such as skin infection and bacteremia. Nasal colonization triggers IgG responses against staphylococcal surface antigens; however, these antibodies cannot prevent subsequent colonization or disease. Here, we describeS. aureusWU1, a multilocus sequence type 88 (ST88) isolate that persistently colonizes the nasopharynx in mice. We report that staphylococcal protein A (SpA) is required for persistence ofS. aureusWU1 in the nasopharynx. Compared to animals colonized by wild-typeS. aureus, mice colonized with the Δspavariant mount increased IgG responses against staphylococcal colonization determinants. Immunization of mice with a nontoxigenic SpA variant, which cannot cross-link B cell receptors and divert antibody responses, elicits protein A-neutralizing antibodies that promote IgG responses against colonizingS. aureusand diminish pathogen persistence.IMPORTANCEStaphylococcus aureuspersistently colonizes the nasopharynx in about one-third of the human population, thereby promoting community- and hospital-acquired infections. Antibiotics are currently used for decolonization of individuals at increased risk of infection. However, the efficacy of antibiotics is limited by recolonization and selection for drug-resistant strains. Here, we propose a model of how staphylococcal protein A (SpA), a B cell superantigen, modifies host immune responses during colonization to support continued persistence ofS. aureusin the nasopharynx. We show that this mechanism can be thwarted by vaccine-induced anti-SpA antibodies that promote IgG responses against staphylococcal antigens and diminish colonization.

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