Role of prophages in Staphylococcus aureus virulence and pathogenicity

• DOI: 10.31237/osf.io/b8ucv_v1
• Publication Date: 2025-03-17T05:39:07Z
• Authors: Roshan Nepal
• Keywords: Prophage; Pathogenicity island

Prophage, a temperate phage embedded in bacterium's genome, affect bacterial fitness multiple ways, including infectivity, toxin secretion, virulence regulation, surface modification, immune evasion, and microbiome competition. Studies have revealed that prophages significantly impact the distribution spread of antimicrobial resistance. Lysogenic conversion by introduces novel accessory functions to bacteria, enhancing fitness, host adaptation persistence different econiches. Prophages can also be triggered stress conditions, such as exposure ultraviolet (UV) radiation, antibiotics, or other chemical agents. Antibiotic-mediated prophage induction is known cause high frequency mobilization, implying certain clinical strains carrying virulent may unintended consequences from antibiotics. For example, hlb-converting (also ϕSa3int) Staphylococcus aureus encodes exotoxins modulatory molecules inhibit human innate immunity, increasing pathogenicity. This property contributes chronic infections inflammation, rhinosinusitis (CRS). Moreover, sub-lethal concentrations fluoroquinolones, trimethoprim, β-lactams are trigger S. aureus, accelerating dissemination prophage-encoded factors avirulent strains. In this study, our first goal was identify describe found isolates recovered CRS patients examine their relationship disease phenotype severity. We aimed determine whether these could produce active reinfecting particles under commonly used antibiotics steroids. Furthermore, we explored links between inducible non-inducible biofilm formation, metabolic activity, Finally, investigated genomic phenotypic plasticity changes its extracellular proteome following acquisition ϕSa3int prophage, which one most frequently with nasal polyp (CRSwNP) patients. To achieve goals, various computational tools regions genomes (N = 66) primarily isolated patients' sinonasal cavities. then detected antibiotic resistance genes within bacteria. measure severity patients, computed tomography Lund Mackay scores. determined patterns using broth microdilution method identified minimum inhibitory concentration (MIC). Using sub- MIC steroids, induced assessed biomass activity relation inducibility. observed beta-hemolysis on sheep blood agar understand prevalence human-adapted aureus. Moving forward, then, biofilm-forming (SA333) transduced it into another Sa3int-prophage-free (SA222, relatively low forming) isolate obtain laboratory-generated 'lysogen'. confirmed successful integration hlb-gene stable lysogenic short- long-read sequencing. compared growth kinetics, biomass, parent lysogen establishing curves, crystal violet resazurin assays. quantified exoproteins secreted lysogens mass spectrophotometry encoded All obtained 57) control 9) carried at least (average 3.6 prophages/isolate), contributing up 7.7% genome. Based completeness scores, nearly 85% (56/66) had intact were likely inducible. belonging type 3 integrase (ϕSa3int-type) prevalent (40%), followed ϕSa2int (14%). The harbored distinct set genes: ϕSa3int-group often evasion cluster like sak, scn, chp, sea, while ϕSa2int-group leukocidins lukE/D. Intact more than without (CRSsNP) (p 0.0021). Similarly, frequent CRSwNP CRSsNP 0.0008). Spontaneous (SPI) around 26% (17/66) isolates, mitomycin C dependent almost 52% (34/66) isolates. Most showing prophage(s). Exposure exponentially growing bacteria sub-inhibitory enhanced SPI 50% lysogens. Among tested, ciprofloxacin potent inducer inducing 51% amoxicillin, doxycycline, mupirocin, clindamycin, azithromycin, all release > 40% There no correlation harboring inactive activity. However, score lower, role lysogeny disease. addition, beta-hemolysin absent 92% cavities Integration ~43.8 kb hemolysin-producing (SA222) down-regulated expression, Sa3int-type disruption production. change adhesion primary epithelial cells, after integration. altered expression proteins, both encoded. Altogether, thirty-eight differentially regulated lysogen, recipient strain SA222. there significant upregulation 21 (55.3%), staphylokinase (sak), SCIN (scn), intercellular protein B (icaB), downregulation 17 (44.7%), (hlb/sph) outer membrane porin (phoE). upregulated proteins for immunomodulation helps escape immunity infection. summary, research has expanded understanding among (CRS) potential development diverse types limited geographic area specific population suffering CRS. suggests presence range contribute adaptability Our findings shed light mobilization. Therefore, underscores importance minimizing unnecessary use hazards associated Such promote not only but accelerates caution against poly-lysogeny, worsen pathogenicity an through accumulation auxiliary phage-encoded traits.