Molecular detection of virulence genes in bacterial isolates from patients with bronchial asthma in Al-Anbar, Iraq

Virulence Genes in Asthma-Associated Bacteria

Abstract

Objectives: This study aimed to isolate and identify bacteria from the respiratory tract of bronchial asthma patients and molecularly detect key virulence genes associated with these isolates.

Methods: A total of 168 samples were collected from patients with bronchial asthma. Bacterial isolates were identified using standard clinical microbiological methods. Polymerase chain reaction (PCR) was employed to detect the presence of virulence genes, including hlB (Staphylococcus aureus and S. epidermidis), ndvB (Escherichia coli), ureR (Proteus mirabilis), OmpA (Acinetobacter baumannii), Prot_clp (Klebsiella pneumoniae and K. oxytoca), lasB (Pseudomonas aeruginosa), and bibA (Streptococcus pneumoniae).

Results: Bacterial growth was obtained from all 168 samples. The distribution of virulence genes was species-specific: Prot_clp was detected in 100% (12/12) of K. pneumoniae and 40% (2/5) of K. oxytoca isolates. The lasB gene was present in 100% (17/17) of P. aeruginosa isolates. The ndvB gene was absent in all E. coli isolates (0/17). The OmpA gene was found in 76.5% (13/17) of A. baumannii isolates. The ureR gene was present in 100% (6/6) of P. mirabilis isolates. The hlB gene was confirmed in 100% (14/14) of S. aureus isolates but absent in all S. epidermidis isolates. Finally, the bibA gene was detected in 100% (10/10) of S. pneumoniae isolates.

Conclusions: Bacterial isolates from asthma patients harboured a high prevalence of specific virulence genes. These findings highlight the potential contribution of bacterial virulence factors to the pathophysiology of asthma and underscore the value of molecular methods in complementing traditional bacteriological diagnostics to better understand infection severity.