Burkholderia cepacia: A Rare Source of Endocarditis

A 37-year-old male with a past medical history of previous mitral valve replacement due to bacterial endocarditis and intravenous (IV) drug use was found to have Burkholderia cepacia bacteremia. Transesophageal echocardiogram revealed large mitral and tricuspid valve vegetations. Medical management was initially attempted but his bacteremia persisted, and he required urgent prosthetic mitral valve replacement and native tricuspid valve replacement. Prosthetic valve endocarditis has been associated with surgery in 48.9% of patients and a mortality of 22.8%. In patients with prosthetic valve endocarditis due to B. cepacia, valve replacement occurred in approximately 61.5% of patients and mortality is estimated to be 33.3%. To our knowledge, this is one of only a few prosthetic valve endocarditis cases caused solely by B. cepacia and our case is the first to affect multiple valves including prosthetic and native valves.

Structural and Functional Insights into the Biofilm-Associated BceF Tyrosine Kinase Domain from Burkholderia cepacia

BceF is a bacterial tyrosine kinase (BY-kinase) from Burkholderia cepacia, a Gram-negative bacterium accountable for respiratory infections in immunocompromised and cystic fibrosis patients. BceF is involved in the production of exopolysaccharides secreted to the biofilm matrix and promotes resistant and aggressive infections. BY-kinases share no homology with mammalian kinases, and thereby offer a means to develop novel and specific antivirulence drugs. Here, we report the crystal structure of the BceF kinase domain at 1.85 Å resolution. The isolated BceF kinase domain is assembled as a dimer in solution and crystallized as a dimer in the asymmetric unit with endogenous adenosine-diphosphate bound at the active sites. The low enzymatic efficiency measured in solution may be explained by the partial obstruction of the active sites at the crystallographic dimer interface. This study provides insights into self-assembly and the specific activity of isolated catalytic domains. Several unique variations around the active site compared to other BY-kinases may allow for structure-based design of specific inhibitors to target Burkholderia cepacia virulence.

Investigation of an outbreak of Burkholderia cepacia infection caused by drug contamination in a tertiary hospital in China

BACKGROUND

Contamination of drugs used in minimally invasive treatment may to lead to infection outbreaks and catastrophic public health events that require prompt detection and control. Our aim was to investigate the outbreak of Burkholderia cepacia infection and its source in a tertiary care, general hospital in Beijing, China.

METHODS

We investigated the outbreak of B cepacia infection from January 2017 to March 2018. The investigation included a detailed review of all cases, and field investigations. Environmental and product cultures were performed at the microbiology laboratory in the hospital. Isolates were evaluated for molecular relatedness using pulsed-field gel electrophoresis performed in an independent laboratory.

RESULTS

In total, 9 patients were infected from November 2017 to March 2018, and all patients had undergone the following surgeries: transurethral resection of the prostate (n = 4), perineal prostate biopsy (n = 2), transurethral resection of bladder tumors (n = 2), and ureteroscopy (n = 1). B cepacia was isolated from the urine of 9 patients, blood of 2 patients, grilles used for puncturing, and 2 samples in 1 batch of analgesic gels. Pulsed-field gel electrophoresis confirmed that the isolates from the patients and gels were homologous.

CONCLUSIONS

Our investigation revealed that the outbreak of B cepacia infection was caused by drug contamination.

Investigational inhaled therapies for non-CF bronchiectasis

INTRODUCTION

Bronchiectasis not related to cystic fibrosis (non-CF bronchiectasis) are associated with a high unmet therapeutic need due to the lack of specifically authorized medications, especially via the inhalation route. In non-CF bronchiectasis chronic infection with Pseudomonas aeruginosa is common and favored by the persistent local inflammation and viscid sputum production. Therefore inhaled antibiotics, mucolytics or anti-inflammatory agents could represent appropriate therapeutic interventions in this setting.

AREAS COVERED

This review herein discusses the inhaled therapies currently under investigation for non-CF bronchiectasis and their potential therapeutic positioning in exacerbation versus stable state.

EXPERT OPINION

Inhaled antipseudomonal antibiotics are of promising efficacy, but further efforts should also be made to detect bactericidal approaches against Burkholderia cepacia complex, and to interfere chronic inflammation topically.