Isolation and Molecular Diagnosis of Bacteria Isolated (S. aureus) From Patients with Post-Surgical Sinusitis

Background: Sinusitis is caused most often by bacteria and is one of the most serious potential complications of endoscopic sinus surgery. This disorder is a major cause of morbidity and cost of treatment; S. aureus is one of its major causal bacteria.  The aim of this study was to isolate and identify S. aureus from clinically diagnosed post-surgical sinusitis patients, characterize virulence factors and drug susceptibility patterns.  One hundred and twenty persons were included in the study who suffered from sinusitis after FESS. The patients were enrolled for 12 months. The middle meatus was the site of sterile collection for the nasal swabs. These were cultured on selective media and biochemical tests were performed. The molecular technique specifically targeted the S. aureus nuc gene and was performed using a polymerase chain reaction (PCR). Antibiotic susceptibility was determined using Clinical and Laboratory Standards Institute (CLSI) guidelines in the disc diffusion method. Amplification of the mecA gene and cefoxitin disc screening were used to discover methicillin resistance.  

Results: A prevalence rate of 39.2% was determined based on the 47 patients out of 120 who tested positive for S. aureus. The results obtained by phenotypic techniques and nuc gene amplification were in perfect accord with each other. 40.4% (19 isolates) were (MRSA). High prevalence of resistance was observed for ciprofloxacin (55.3%), erythromycin (68.1%) and penicillin (91.5%). Nonetheless, vancomycin and linezolid were able to keep the isolates in check. All of the isolates had the mecA gene, and the 310 base pair amplicons showed that the genotype was resistant.

Conclusions: Sinusitis following surgery is often caused by Staphylococcus aureus, and this is especially true with methicillin-resistant strains. Routine molecular characterisation and antimicrobial susceptibility testing are necessary to guide suitable therapeutic strategies due to the significant frequency of antibiotic resistance. To reduce the impact of antibiotic resistance in surgical settings, it is crucial to implement infection control measures and utilise antibiotics wisely.