Successful Lung Re-transplant in a Patient with Cepacia Syndrome due to Burkholderia ambifaria

CysB Is a Key Regulator of the Antifungal Activity of Burkholderia pyrrocinia JK-SH007

Burkholderia pyrrocinia JK-SH007 can effectively control poplar canker caused by pathogenic fungi. Its antifungal mechanism remains to be explored. Here, we characterized the functional role of CysB in B. pyrrocinia JK-SH007. This protein was shown to be responsible for the synthesis of cysteine and the siderophore ornibactin, as well as the antifungal activity of B. pyrrocinia JK-SH007. We found that deletion of the cysB gene reduced the antifungal activity and production of the siderophore ornibactin in B. pyrrocinia JK-SH007. However, supplementation with cysteine largely restored these two abilities in the mutant. Further global transcriptome analysis demonstrated that the amino acid metabolic pathway was significantly affected and that some sRNAs were significantly upregulated and targeted the iron-sulfur metabolic pathway by TargetRNA2 prediction. Therefore, we suggest that, in B. pyrrocinia JK-SH007, CysB can regulate the expression of genes related to Fe-S clusters in the iron-sulfur metabolic pathway to affect the antifungal activity of B. pyrrocinia JK-SH007. These findings provide new insights into the various biological functions regulated by CysB in B. pyrrocinia JK-SH007 and the relationship between iron-sulfur metabolic pathways and fungal inhibitory substances. Additionally, they lay the foundation for further investigation of the main antagonistic substances of B. pyrrocinia JK-SH007.

Cystic fibrosis year in review 2019: Section 2 pulmonary disease and infections

During the year 2019, research and case reports or series in the field of cystic fibrosis (CF) were in abundance. To adequately address the large body of CF research published during 2019, the CF year in review will be divided into three sections. This report is the second section, focusing specifically on new research related to pulmonary disease and infections. Additional sections will concentrate on CF transmembrane conductance regulator modulators and the multisystem effects of CF. It is an exciting time to be providing care for patients and their families with CF with all the exciting new discoveries that will be shared in these reviews.

Cepacia syndrome in cystic fibrosis: A systematic review of the literature and possible new perspectives in treatment

BACKGROUND

Cepacia syndrome (CS) is an acute, necrotizing pneumonia with a high mortality rate, occurring in patients with cystic fibrosis (CF) infected with Burkholderia cepacia complex (BCC). Due to its low incidence, data on this condition are limited.

METHODS

We conducted a systematic review of the reported cases of CS by searching MEDLINE, Embase and the Cochrane Library to improve knowledge of this rare but potentially lethal condition.

RESULTS

We included 15 eligible articles, describing 18 cases (9 females) of CS. Median age at onset was 22 years (range: 10-60 years); median time to CS after first infection by BCC was 5 years (range: 1-26 years). Burkholderia cenocepacia was the most frequently reported causative agent. All patients received intravenous antibiotic treatment (most frequently including cotrimoxazole), while inhaled antibiotics were used in five patients (27.8%). Immunosuppressant agents were the most commonly prescribed supportive treatment (n = 7, 38.9%). Half of the patients died (9/18, 50%).

CONCLUSIONS

This study describes epidemiological, clinical characteristics, and prognosis of CS cases reported over the last 24 years. CS is a rare yet severe complication of BCC infection in patients with CF, which occurs several years after BCC colonization and has a negative outcome in 50% of the patients. Data are too scanty to identify the most effective therapeutic approach.

Multiresistant organisms: bacteria and beyond

PURPOSE OF REVIEW

Infections with multiresistant organisms are an emerging problem, cause early mortality post lung transplantation and are sometimes associated with graft dysfunction. Frequently they raise questions about the selection of lung transplant candidates and therapeutic management post lung transplantation. There are no guidelines and management must be individualized. This review summarizes the available therapeutic options in cases of multidrug-resistant (MDR) organisms and outcomes after lung transplant.

RECENT FINDINGS

Improvements in diagnosis, new and more effective drugs and the experience gained in the management of these infections in lung transplantation, lead to a more optimistic horizon than that found a decade ago.

SUMMARY

Update on the management of Burkholderia cepacia complex, Mycobacterium abscessus complex, Aspergillus spp., Scedosporium spp. and Lomentospora prolificans infections. This review clarifies current posttransplant outcomes and adds a little hope in these scenarios.

Iron metabolism in bacterial cells: from physiological significance to a new class of antimicrobial agents

Infectious complications in the respiratory tract caused by microorganisms from the Burkholderia cepacia complex are the main cause of death among patients with cystic fibrosis. Natural and acquired resistance mechanisms allow Burkholderia cepacia complex pathogens to adapt to the conditions of regular antibiotic therapy, which necessitates the use of antibacterial drugs with an alternative mechanism of action. Studies on the importance of iron as an essential factor in the metabolism of bacteria and methods of its acquisition from the environment contributed to the development of a new antibiotic from a number of cephalosporins – cefiderocol. In the structure of cefiderocol, a fragment is formed that imitates siderophores – chelating molecules that ensure the transport of iron ions into the internal environment of the microorganism. A unique mechanism, described in the scientific literature as a “Trojan horse”, allows antibiotic molecules conjugated with siderophores to effectively penetrate into the bacterial cell, exerting a bactericidal effect. Thus, cefiderocol can be used to treat infectious complications in the lungs of patients with cystic fibrosis caused by bacteria from the Burkholderia cepacia complex, including multidrug-resistant strains. In addition, the spectrum of activity of cefiderocol allows the use of this antibiotic in the treatment of infections caused by nosocomial gram-negative bacteria such as Enterobacterales, Acinetobacter, Pseudomonas and Stenotrophomonas.

Consensus document for the selection of lung transplant candidates: An update from the International Society for Heart and Lung Transplantation

Tens of thousands of patients with advanced lung diseases may be eligible to be considered as potential candidates for lung transplant around the world each year. The timing of referral, evaluation, determination of candidacy, and listing of candidates continues to pose challenges and even ethical dilemmas. To address these challenges, the International Society for Heart and Lung Transplantation appointed an international group of members to review the literature, to consider recent advances in the management of advanced lung diseases, and to update prior consensus documents on the selection of lung transplant candidates. The purpose of this updated consensus document is to assist providers throughout the world who are caring for patients with pulmonary disease to identify potential candidates for lung transplant, to optimize the timing of the referral of these patients to lung transplant centers, and to provide transplant centers with a framework for evaluating and selecting candidates. In addition to addressing general considerations and providing disease specific recommendations for referral and listing, this updated consensus document includes an ethical framework, a recognition of the variability in acceptance of risk between transplant centers, and establishes a system to account for how a combination of risk factors may be taken into consideration in candidate selection for lung transplantation.

The Impact of Resistant Bacterial Pathogens including Pseudomonas aeruginosa and Burkholderia on Lung Transplant Outcomes

Pseudomonas and Burkholderia are gram-negative organisms that achieve colonization within the lungs of patients with cystic fibrosis, and are associated with accelerated pulmonary function decline. Multidrug resistance is a hallmark of these organisms, which makes eradication efforts difficult. Furthermore, the literature has outlined increased morbidity and mortality for lung transplant (LTx) recipients infected with these bacterial genera. Indeed, many treatment centers have considered Burkholderia cepacia infection an absolute contraindication to LTx. Ongoing research has delineated different species within the B. cepacia complex (BCC), with significantly varied morbidity and survival profiles. This review considers the current evidence for LTx outcomes between the different subspecies encompassed within these genera as well as prophylactic and management options. The availability of meta-genomic tools will make differentiation between species within these groups easier in the future, and will allow more evidence-based decisions to be made regarding suitability of candidates colonized with these resistant bacteria for LTx. This review suggests that based on the current evidence, not all species of BCC should be considered contraindications to LTx, going forward.