Occurrence and antibiotic susceptibility profiles of Burkholderia cepaciacomplex in coastal marine environment

Abstract

During an environmental study of bacterial resistance to antibiotics in coastal waters of the Kaštela Bay, Adriatic Sea, Croatia, 47 Burkholderia cepacia complex (Bcc) isolates were recovered from seawater and mussel (Mytilus galloprovincialis) samples. All isolates showed multiple antibiotic resistance. Among the isolates, two Burkholderia cenocepacia isolates produced chromosomally encoded TEM-116 extended-spectrum β-lactamase (ESBL). Analysis of outer membrane proteins revealed that decreased expression of a 36-kDa protein could be associated with a high level of β-lactam resistance in both isolates. Phenotypic study of efflux system also indicated an over-expression of Resistance-Nodulation-Cell Division (RND) efflux-mediated mechanism in one of the isolates. This study demonstrated the presence of Bcc inseawater and M. galloprovincialis, which gives evidence that coastal marine environment, including mussels, could be considered as a reservoir for Bcc species. Detection of ESBL-encoding genes indicates the potential role of these bacteria in the maintenance and dispersion of antibiotic resistance genes.

Keywords:

• Burkholderia cepacia complex
• TEM-116
• ESBL
• Mytilus galloprovincialis
• coastal marine environment

Acknowledgments

This work was supported by Ministry of Science, Education and Sports, Republic of Croatia, project “Faecal indicator and potential pathogens in coastal and marine waters”, Grant 177-0000000-3182 and project “Mechanisms of maintenance genome stability in higher plants”, Grant 177-1191196-0829.