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Diagn Microbiol Infect Dis. 2018 Nov;92(3):253-258. doi: 10.1016/j.diagmicrobio.2018.06.005. Epub 2018 Jun 18.

Sequence heterogeneity of the PenA carbapenemase in clinical isolates of Burkholderia multivorans.

Author information

1
Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
2
J. Craig Venter Institute (JCVI), Rockville, MD 20850, USA.
3
Department of Pediatrics and Communicable Disease, University of Michigan Medical School, Ann Arbor, MI 48103, USA.
4
Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA; Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA. Electronic address: krisztina.papp@va.gov.

Abstract

Multidrug-resistant gram-negative pathogens are a significant health threat. Burkholderia spp. encompass a complex subset of gram-negative bacteria with a wide range of biological functions that include human, animal, and plant pathogens. The treatment of infections caused by Burkholderia spp. is problematic due to their inherent resistance to multiple antibiotics. The major β-lactam resistance determinant expressed in Burkholderia spp. is a class A β-lactamase of the PenA family. In this study, significant amino acid sequence heterogeneity was discovered in PenA (37 novel variants) within a panel of 48 different strains of Burkholderia multivorans isolated from individuals with cystic fibrosis. Phylogenetic analysis distributed the 37 variants into 5 groups based on their primary amino acid sequences. Amino acid substitutions were present throughout the entire β-lactamase and did not congregate to specific regions of the protein. The PenA variants possessed 5 to 17 single amino acid changes. The N189S and S286I substitutions were most prevalent and found in all variants. Due to the sequence heterogeneity in PenA, a highly conserved peptide (18 amino acids) within PenA was chosen as the antigen for polyclonal antibody production in order to measure expression of PenA within the 48 clinical isolates of B. multivorans. Characterization of the anti-PenA peptide antibody, using immunoblotting approaches, exposed several unique features of this antibody (i.e., detected <500 pg of purified PenA, all 37 PenA variants in B. multivorans, and Pen-like β-lactamases from other species within the Burkholderia cepacia complex). The significant sequence heterogeneity found in PenA may have occurred due to selective pressure (e.g., exposure to antimicrobial therapy) within the host. The contribution of these changes warrants further investigation.

KEYWORDS:

Burkholderia; Sequencing; β-Lactamase

PMID:
29983287
PMCID:
PMC6173980
[Available on 2019-11-01]
DOI:
10.1016/j.diagmicrobio.2018.06.005
[Indexed for MEDLINE]
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