Detection of biofilm formation and antibiotic resistance genes in multidrug-resistant Burkholderia sp. isolated from agricultural soil

Background Burkholderia are environmental bacteria mostly distributed in soil and water. Species of these bacteria can cause melioidosis in humans and animals, as well as necrotizing pneumonia in patients with cystic fibrosis. Detection of biofilm formation and antibiotic resistance genes in these bacteria will help to know mechanisms of resistance to drugs for treating infected patients. This study aims to isolate and determine formation of biofilm and presence of antibiotic resistance genes in Burkholderia pseudomallei and Burkholderia cepacia . from agricultural soil. Methods Burkholderia pseudomallei and Burkholderia cepacia were isolated from agricultural soil and putatively identified by morphological, biochemical, and species-specific amplification of the recA gene. The potential of the isolates to form biofilms, their antibiotic susceptibility, and the presence of β-lactamase ( penA ) and efflux pump ( bpeF ) genes were examined. Results Eleven Burkholderia pseudomallei and twenty-four Burkholderia cepacia isolates were putatively identified with PCR amplification of recA gene. In all, 82% of B. pseudomallei and 63% of B. cepacia isolates formed biofilm. All isolates showed resistance to imipenem (10 µg), amoxicillin/clavulanate (20/10 µg), meropenem (10 µg), ceftazidime (30 µg), kanamycin (30 µg), and cefotaxime (30 µg), which are conventionally used to treat Burkholderia infections. Again, all B. pseudomallei and B. cepacia had efflux pump bpeF gene, while 27% of B. pseudomallei and 21% of B. cepacia possessed the β-lactamase penA gene. Conclusion This study isolated biofilm-forming and multidrug-resistant B. pseudomallei and B. cepacia from soil samples. This study suggests that biofilm formation and antibiotic resistance genes may contribute to multidrug resistance in Burkholderia sp.