Novel Class 1 Integron in Clinical Isolates of Burkholderia cepacia Complex

Objectives The potent nosocomial pathogens, Burkholderia cepacia complex (BCC), comprise a group of diverse, metabolically active bacteria that cause infections in patients with cystic fibrosis (CF) and chronic granulomatous disease (CGD). They have been identified as the leading cause of bacteraemia and sepsis in patients with CF and non-CF. The primary challenge in treating Burkholderia cepacia is its intrinsic resistance to multiple antibiotics, forming a baseline resistance profile. This study aimed to investigate integron-associated acquired resistance mechanisms in selected clinical Burkholderia isolates. Material and Methods Clinical Burkholderia cepacia isolates were tested for antimicrobial susceptibility and screened for integrons using the polymerase chain reaction (PCR). The integron-positive isolates were further Sanger sequenced to detect the presence of antimicrobial resistance genes within the cassettes. Result The Burkholderia cepacia isolates tested according to the CLSI guidelines showed the highest resistance to amoxicillin-clavulanic Acid (85%). Based on the susceptibility patterns, 55 multidrug-resistant (MDR) isolates were further screened for integrons. Although the prevalence was low, 14 isolates showed the presence of integrons during PCR amplification. Sanger sequencing revealed that one isolate, B6981, carried an integrase and two antibiotic resistance genes (ARGs): dihydrofolate reductase ( dfrA5 ) and erythromycin esterase ( ereA2 ), which code for trimethoprim and erythromycin resistance, respectively. The other isolate, B591, harboured only the integrase gene. The sequencing results were correlated with the phenotypic results. Conclusion Although a majority of Burkholderia isolates were found to be multidrug-resistant, the study highlights the low prevalence of integrons among these isolates, suggesting the presence of other resistance mechanisms.