Characterization of bla TEM and bla CTX-M beta-lactam resistance genes in chronic rhinosinusitis

Abstract

Abstract Background Chronic sinusitis is one of the most challenging health problems of contemporary society. Although several treatment methods have been defined, a comprehensive understanding of the underlying causes (e.g., antibiotic resistance) is still elusive. The aim of this study was to characterize two of the main extended-spectrum beta-lactamase genes—i.e., bla TEM and bla CTX-M genes—and investigate antimicrobial resistance in bacteria isolated from chronic sinusitis. Samples from 70 chronic sinusitis patients and 20 healthy individuals (controls) were analyzed for the presence of bla TEM and bla CTX-M resistance genes using the polymerase chain reaction (PCR) test, followed by gene sequence analysis. Results Phenotypic and genotypic beta-lactam resistance was observed in 58.7% and 61.54% of the gram-negative isolates, respectively, with 38.46% carrying the bla TEM gene and 34.62% harboring the bla CTX-M gene. Sequencing data indicated high heterogeneity in bla CTX-M genes (69–100% similarity to reported sequences) and lower heterogeneity in bla TEM genes (93–99%). Conclusion Broad-spectrum beta-lactam resistance is a major pathogenesis factor in chronic rhinosinusitis, and careful consideration is required for antimicrobial therapy. High bla CTX-M heterogeneity could mean high horizontal transfer rate of this gene and warrant a surveillance program.

Keywords

• Chronic rhinosinusitis
• bla TEM
• bla CTX-M
• Broad-spectrum beta-lactamase
• PCR