Cystic Fibrosis
Chronic jejuno-colonic fistula and intestinal malabsorption due to multiple magnet ingestions: A case report and systematic review
Ulus Travma Acil Cerrahi Derg. 2024 May;30(5):361-369. doi: 10.14744/tjtes.2024.50845.
ABSTRACT
Magnet ingestion in children can lead to serious complications, both acutely and chronically. This case report discusses the treatment approach for a case involving multiple magnet ingestions, which resulted in a jejuno-colonic fistula, segmental intestinal volvulus, hepa-tosteatosis, and renal calculus detected at a late stage. Additionally, we conducted a literature review to explore the characteristics of intestinal fistulas caused by magnet ingestion. A six-year-old girl was admitted to the Pediatric Gastroenterology Department pre-senting with intermittent abdominal pain, vomiting, and diarrhea persisting for two years. Initial differential diagnoses included celiac disease, cystic fibrosis, inflammatory bowel disease, and tuberculosis, yet the etiology remained elusive. The Pediatric Surgery team was consulted after a jejuno-colonic fistula was suspected based on magnetic resonance imaging findings. The physical examination revealed no signs of acute abdomen but showed mild abdominal distension. Subsequent upper gastrointestinal series and contrast enema graphy confirmed a jejuno-colonic fistula and segmental volvulus. The family later reported that the child had swallowed a magnet two years prior, and medical follow-up had stopped after the spontaneous expulsion of the magnets within one to two weeks. Surgical intervention was necessary to correct the volvulus and repair the large jejuno-colonic fistula. To identify relevant studies, we conducted a detailed literature search on magnet ingestion and gastrointestinal fistulas according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We identified 44 articles encompassing 55 cases where symptoms did not manifest in the acute phase and acute abdomen was not observed. In 29 cases, the time of magnet ingestion was unknown. Among the 26 cases with a known ingestion time, the average duration until fistula detection was 22.8 days (range: 1-90 days). Fistula repairs were performed via laparotomy in 47 cases.
PMID:38738679 | DOI:10.14744/tjtes.2024.50845
Challenging fungal infections in cystic fibrosis: a case of mixed Aspergillus species infection and antifungal combination testing
Access Microbiol. 2024 Apr 19;6(4):000758.v3. doi: 10.1099/acmi.0.000758.v3. eCollection 2024.
ABSTRACT
Aspergillus stands as the predominant fungal genus in the airways of cystic fibrosis (CF) patients, significantly contributing to their morbidity and mortality. Aspergillus fumigatus represents the primary causative species for infections, though the emergence of rare species within the Aspergillus section Fumigati has become noteworthy. Among these, Aspergillus lentulus is particularly significant due to its frequent misidentification and intrinsic resistance to azole antifungal agents. In the management of invasive aspergillosis and resistant infections, combination antifungal therapy has proven to be an effective approach. This report documents a case involving the death of a CF patient due to a pulmonary exacerbation linked to the colonization of multiple Aspergillus species, including A. lentulus, A. fumigatus, and A. terreus, and treated with Itraconazole (ITC) monotherapy. We delineated the procedures used to characterize the Aspergillus isolates in clinical settings and simulated in vitro the impact of the combination antifungal therapy on the isolates obtained from the patient. We evaluated three different combinations: Amphotericin B (AMB)+Voriconazole (VRC), AMB+Anidulafungin (AND), and VRC+AND. Notably, all strains isolated from the patient exhibited a significant decrease in their minimum inhibitory concentration (MIC) or minimum effective concentration (MEC) values when treated with all antifungal combinations. The VRC+AMB combination demonstrated the most synergistic effects. This case report emphasizes the critical importance of susceptibility testing and precise identification of Aspergillus species to enhance patient prognosis. It also underscores the potential benefits of combined antifungal treatment, which, in this case, could have led to a more favourable patient outcome.
PMID:38737802 | PMC:PMC11083386 | DOI:10.1099/acmi.0.000758.v3
Airway basal cells from human-induced pluripotent stem cells: a new frontier in cystic fibrosis research
Front Cell Dev Biol. 2024 Apr 26;12:1336392. doi: 10.3389/fcell.2024.1336392. eCollection 2024.
ABSTRACT
Human-induced airway basal cells (hiBCs) derived from human-induced pluripotent stem cells (hiPSCs) offer a promising cell model for studying lung diseases, regenerative medicine, and developing new gene therapy methods. We analyzed existing differentiation protocols and proposed our own protocol for obtaining hiBCs, which involves step-by-step differentiation of hiPSCs into definitive endoderm, anterior foregut endoderm, NKX2.1+ lung progenitors, and cultivation on basal cell medium with subsequent cell sorting using the surface marker CD271 (NGFR). We derived hiBCs from two healthy cell lines and three cell lines with cystic fibrosis (CF). The obtained hiBCs, expressing basal cell markers (NGFR, KRT5, and TP63), could differentiate into lung organoids (LOs). We demonstrated that LOs derived from hiBCs can assess cystic fibrosis transmembrane conductance regulator (CFTR) channel function using the forskolin-induced swelling (FIS) assay. We also carried out non-viral (electroporation) and viral (recombinant adeno-associated virus (rAAV)) serotypes 6 and 9 and recombinant adenovirus (rAdV) serotype 5 transgene delivery to hiBCs and showed that rAAV serotype 6 is most effective against hiBCs, potentially applicable for gene therapy research.
PMID:38737127 | PMC:PMC11082282 | DOI:10.3389/fcell.2024.1336392
Maternal and Fetal Outcomes in Multiparous Women with Cystic Fibrosis
Respir Med. 2024 May 10:107654. doi: 10.1016/j.rmed.2024.107654. Online ahead of print.
ABSTRACT
BACKGROUND: Quality of life and survival in Cystic Fibrosis (CF) have improved dramatically, making family planning a feasible option. Maternal and perinatal outcomes in women with CF (wwCF) are similar to those seen in the general population. However, the effect of undergoing multiple pregnancies is unknown.
METHODS: A multinational-multicenter retrospective cohort study. Data was obtained from 18 centers worldwide, anonymously, on wwCF 18-45 years old, including isease severity and outcome, as well as obstetric and newborn complications. Data was analyzed, within each individual patient to compare the outcomes of an initial pregnancy (1st or 2nd) with a multigravid pregnancy (≥3) as well as secondary analysis of grouped data to identify risk factors for disease progression or adverse neonatal outcomes. Three time periods were assessed - before, during, and after pregnancy.
RESULTS: The study population included 141 wwCF of whom 41 (29%) had ≥3 pregnancies, "multiparous". Data was collected on 246 pregnancies, between 1973 and 2020, 69 (28%) were multiparous. A greater decline in ppFEV1 was seen with multiparous women, primarily in pancreatic insufficient (PI) wwCF and those with two severe (class I-III) mutations. Multigravid pregnancies were shorter, especially in wwCF over 30 years old, who had high rates of prematurity and newborn complications. There was no effect on pulmonary exacerbations or disease-related complications.
CONCLUSIONS: Multiple pregnancies in wwCF are associated with accelerated respiratory deterioration and higher rates of preterm births. Therefore, strict follow-up by a multidisciplinary CF and obstetric team is needed in women who desire to carry multiple pregnancies.
PMID:38735372 | DOI:10.1016/j.rmed.2024.107654
Exploring the dynamics of mixed-species biofilms involving Candida spp. and bacteria in cystic fibrosis
Arch Microbiol. 2024 May 11;206(6):255. doi: 10.1007/s00203-024-03967-9.
ABSTRACT
Cystic fibrosis (CF) is an inherited disease that results from mutations in the gene responsible for the cystic fibrosis transmembrane conductance regulator (CFTR). The airways become clogged with thick, viscous mucus that traps microbes in respiratory tracts, facilitating colonization, inflammation and infection. CF is recognized as a biofilm-associated disease, it is commonly polymicrobial and can develop in biofilms. This review discusses Candida spp. and both Gram-positive and Gram-negative bacterial biofilms that affect the airways and cause pulmonary infections in the CF context, with a particular focus on mixed-species biofilms. In addition, the review explores the intricate interactions between fungal and bacterial species within these biofilms and elucidates the underlying molecular mechanisms that govern their dynamics. Moreover, the review addresses the multifaceted issue of antimicrobial resistance in the context of CF-associated biofilms. By synthesizing current knowledge and research findings, this review aims to provide insights into the pathogenesis of CF-related infections and identify potential therapeutic approaches to manage and combat these complex biofilm-mediated infections.
PMID:38734793 | DOI:10.1007/s00203-024-03967-9
The clinical utility of sequencing the entirety of CFTR
J Cyst Fibros. 2024 May 10:S1569-1993(24)00062-6. doi: 10.1016/j.jcf.2024.04.018. Online ahead of print.
ABSTRACT
BACKGROUND: Cystic fibrosis (CF) is caused by deleterious variants in each CFTR gene. We investigated the utility of whole-gene CFTR sequencing when fewer than two pathogenic or likely pathogenic (P/LP) variants were detected by conventional testing (sequencing of exons and flanking introns) of CFTR.
METHODS: Individuals with features of CF and a CF-diagnostic sweat chloride concentration with zero or one P/LP variants identified by conventional testing enrolled in the CF Mutation Analysis Program (MAP) underwent whole-gene CFTR sequencing. Replication was performed on individuals enrolled in the CF Genome Project (CFGP), followed by phenotype review and interrogation of other genes.
RESULTS: Whole-gene sequencing identified a second P/LP variant in 20/43 MAP enrollees (47 %) and 10/22 CFGP enrollees (45 %) who had one P/LP variant after conventional testing. No P/LP variants were detected when conventional testing was negative (MAP: n = 43; CFGP: n = 13). Genome-wide analysis was unable to find an alternative etiology in CFGP participants with fewer than two P/LP CFTR variants and CF could not be confirmed in 91 % following phenotype re-review.
CONCLUSIONS: Whole-gene CFTR analysis is beneficial in individuals with one previously-identified P/LP variant and a CF-diagnostic sweat chloride. Negative conventional CFTR testing indicates that the phenotype should be re-evaluated.
PMID:38734509 | DOI:10.1016/j.jcf.2024.04.018
Insights and considerations on CFTR variant reporting in a study of cystic fibrosis patients in Saudi Arabia CFTR 1548del G and 1549del G: Navigating the discovery of novel mutations
Saudi Med J. 2024 May;45(5):541. doi: 10.15537/smj.2024.45.5.20240331.
NO ABSTRACT
PMID:38734430 | DOI:10.15537/smj.2024.45.5.20240331
Association between bronchiectasis exacerbations and longitudinal changes in FEV<sub>1</sub> in patients from the US Bronchiectasis and NTM Research Registry
Respir Med. 2024 May 9:107660. doi: 10.1016/j.rmed.2024.107660. Online ahead of print.
ABSTRACT
BACKGROUND: This study aimed to evaluate the association between the number of non-cystic fibrosis bronchiectasis (bronchiectasis) exacerbations during baseline and follow-up (objective 1) and to identify longitudinal changes in FEV1 associated with exacerbation frequency (objective 2).
METHODS: This was a retrospective cohort study of adult patients enrolled in the US Bronchiectasis and Nontuberculous Mycobacteria Research Registry September 2008 to March 2020. Objective 1 outcome was association between exacerbations during baseline (24 months) and 0-to-24 month and 24-to-48 month follow-up windows. Objective 2 outcomes were change in FEV1 and FEV1 % predicted over 24 months stratified by baseline exacerbation frequency.
RESULTS: Objective 1 cohort (N=520) baseline frequency of any exacerbations was 59.2%. Overall, 71.4% and 75.0% of patients with ≥1 baseline exacerbations had ≥1 exacerbations during the 0-to-24 and 24-to-48 month follow-ups. Having ≥1 exacerbation during baseline was significantly associated with ≥1 exacerbation during the 0-to-24 month (P=0.0085) and 24-to-48 month follow-ups (P=<0.0001). Objective 2 cohort (N=431) baseline FEV1 was significantly lower in patients who had more exacerbations, however decline in FEV1 from baseline was not significantly different between patients with 0, 1, and ≥2 exacerbations. In patients with more baseline exacerbations, FEV1 % predicted was significantly lower at baseline (P<0.0001) and at 12 (P=0.0002) and 24 month follow-ups (P<0.0001).
CONCLUSIONS: Patients with frequent bronchiectasis exacerbations may be more likely than those with less frequent exacerbations to experience disease progression based on future exacerbation frequency and lower FEV1 at baseline, although FEV1 decline may not differ by baseline exacerbation frequency.
PMID:38734153 | DOI:10.1016/j.rmed.2024.107660
Vitamin K Status Based on K1, MK-4, MK-7, and Undercarboxylated Prothrombin Levels in Adolescent and Adult Patients with Cystic Fibrosis: A Cross-Sectional Study
Nutrients. 2024 Apr 29;16(9):1337. doi: 10.3390/nu16091337.
ABSTRACT
The available evidence on vitamin K status in cystic fibrosis (CF) is scarce, lacking data on vitamin K2 (menaquinones-MK). Therefore, we assessed vitamin K1, MK-4 and MK-7 concentrations (LC-MS/MS) in 63 pancreatic insufficient and modulator naïve CF patients, and compared to 61 healthy subjects (HS). Vitamin K1 levels did not differ between studied groups. MK-4 concentrations were higher (median <1st-3rd quartile>: 0.778 <0.589-1.086> vs. 0.349 <0.256-0.469>, p < 0.0001) and MK-7 levels lower (0.150 <0.094-0.259> vs. 0.231 <0.191-0.315>, p = 0.0007) in CF patients than in HS. MK-7 concentrations were higher in CF patients receiving K1 and MK-7 supplementation than in those receiving vitamin K1 alone or no supplementation. Moreover, vitamin K1 concentrations depended on the supplementation regime. Based on multivariate logistic regression analysis, we have found that MK-7 supplementation dose has been the only predictive factor for MK-7 levels. In conclusion, vitamin K1 levels in CF are low if not currently supplemented. MK-4 concentrations in CF patients supplemented with large doses of vitamin K1 are higher than in HS. MK-7 levels in CF subjects not receiving MK-7 supplementation, with no regard to vitamin K1 supplementation, are low. There do not seem to be any good clinical predictive factors for vitamin K status.
PMID:38732584 | DOI:10.3390/nu16091337
Antibiofilm Activity of <em>Combretum micranthum</em> G. Don Catechin-Sugar Phytocomplex on <em>Pseudomonas aeruginosa</em>
Molecules. 2024 May 1;29(9):2091. doi: 10.3390/molecules29092091.
ABSTRACT
Clinicians often have to face infections caused by microorganisms that are difficult to eradicate due to their resistance and/or tolerance to antimicrobials. Among these pathogens, Pseudomonas aeruginosa causes chronic infections due to its ability to form biofilms on medical devices, skin wounds, ulcers and the lungs of patients with Cystic Fibrosis. In this scenario, the plant world represents an important reservoir of natural compounds with antimicrobial and/or antibiofilm properties. In this study, an extract from the leaves of Combretum micranthum G. Don, named Cm4-p, which was previously investigated for its antimicrobial activities, was assayed for its capacity to inhibit biofilm formation and/or to eradicate formed biofilms. The model strain P. aeruginosa PAO1 and its isogenic biofilm hyperproducer derivative B13 were treated with Cm4-p. Preliminary IR, UV-vis, NMR, and mass spectrometry analyses showed that the extract was mainly composed of catechins bearing different sugar moieties. The phytocomplex (3 g/L) inhibited the biofilm formation of both the PAO1 and B13 strains in a significant manner. In light of the obtained results, Cm4-p deserves deeper investigations of its potential in the antimicrobial field.
PMID:38731582 | DOI:10.3390/molecules29092091
Evaluation of Target Attainment for Tobramycin in Children and Adults with Cystic Fibrosis
J Clin Med. 2024 Apr 30;13(9):2641. doi: 10.3390/jcm13092641.
ABSTRACT
Introduction: Patients with cystic fibrosis (CF) commonly experience pulmonary exacerbations, and it is recommended by the TOPIC study to treat this with tobramycin at a dose of 10 mg/kg once daily. The aim of this study was to evaluate the target attainment of the current dosing regimen. Methods: A single-center retrospective cohort study of child and adult patients with CF who received tobramycin between 2019 and 2022 was conducted. Descriptive statistics and linear mixed models were used to assess target attainment for tobramycin. Results: In total, 25 patients (53 courses), of which 10 were children (12 courses) and 15 were adults (41 courses), were included. Those 25 patients all received 10 mg/kg/day. The tobramycin peak concentrations were supratherapeutic in 82.9% and therapeutic in 100.0% of adults and children, respectively. The trough concentrations were outside the target range in 0% and 5.1% of children and adults, respectively. We found lower tobramycin concentrations with the same dose in children compared to adults. Conclusions: This study illustrates the need to validate dosing advice in a real-world setting, as supratherapeutic concentrations of tobramycin were prevalent in adults with CF.
PMID:38731170 | DOI:10.3390/jcm13092641
CRISPR Technology in Lung Diseases: The Example of Lung Cancer and Cystic Fibrosis
Arch Bronconeumol. 2024 Apr 30:S0300-2896(24)00128-5. doi: 10.1016/j.arbres.2024.04.017. Online ahead of print.
NO ABSTRACT
PMID:38729885 | DOI:10.1016/j.arbres.2024.04.017
Identifying people living with cystic fibrosis in the Danish National Patient Registry: A validation study
J Cyst Fibros. 2024 May 9:S1569-1993(24)00066-3. doi: 10.1016/j.jcf.2024.05.003. Online ahead of print.
ABSTRACT
BACKGROUND: The Danish National Patient Registry (DNPR) serves as a valuable resource for scientific research. However, to ensure accurate results in cystic fibrosis (CF) studies that rely on DNPR data, a robust case-identification algorithm is essential. This study aimed to develop and validate algorithms for the reliable identification of CF patients in the DNPR.
METHODS: Using the Danish Cystic Fibrosis Registry (DCFR) as a reference, accuracy measures including sensitivity and positive predictive value (PPV) for case-finding algorithms deployed in the DNPR were calculated. Algorithms were based on minimum number of hospital contacts with CF as the main diagnosis and minimum number of days between first and last contact.
RESULTS: An algorithm requiring a minimum of one hospital contact with CF as the main diagnosis yielded a sensitivity of 96.1 % (95 % CI: 94.2 %; 97.4 %) and a PPV of 84.9 % (82.0 %; 87.4 %). The highest-performing algorithm required minimum 2 hospital visits and a minimum of 182 days between the first and the last contact and yielded a sensitivity of 95.9 % (95 % CI: 94.1 %; 97.2 %), PPV of 91.0 % (95 % CI: 88.6 %; 93.0 %) and a cohort entry delay of 3.2 months at the 75th percentile (95th percentile: 38.7 months).
CONCLUSIONS: The DNPR captures individuals with CF with high sensitivity and is a valuable resource for CF-research. PPV was improved at a minimal cost of sensitivity by increasing requirements of minimum number of hospital contacts and days between first and last contact. Cohort entry delay increased with number of required hospital contacts.
PMID:38729850 | DOI:10.1016/j.jcf.2024.05.003
Heterogeneity in response to Elexacaftor/Tezacaftor/Ivacaftor in people with cystic fibrosis
J Cyst Fibros. 2024 May 9:S1569-1993(24)00057-2. doi: 10.1016/j.jcf.2024.04.013. Online ahead of print.
ABSTRACT
BACKGROUND: Highly effective modulators of the CFTR channel have been demonstrated to dramatically impact disease progression and outcome. However, real-world data indicates that the magnitude of the clinical benefit is not equal among all patients receiving the treatment. We aimed to assess the variability in treatment response (as defined by the 6-month change in sweat chloride concentration, forced expiratory volume in one second [ppFEV1], body mass index [BMI], and CF Questionnaire-Revised [CFQ-R] respiratory domain score) and identify potential predictors in a group of patients receiving Elexacaftor-Tezacaftor-Ivacaftor (ETI) triple combination therapy.
METHODS: This was a single-center, prospective cohort study enrolling adults with CF at a major center in Italy. We used linear regression models to identify a set of potential predictors (including CFTR genotype, sex, age, and baseline clinical characteristics) and estimate the variability in treatment response.
RESULTS: The study included 211 patients (median age: 29 years, range: 12-58). Median changes (10-90th percentile) from baseline were: - 56 mEq/L (-76; -27) for sweat chloride concentration, +14.5 points (2.5; 32.0) for ppFEV1, +0.33 standard deviation scores (-0.13; 1.05) for BMI and +17 points (0; 39) for the CFQ-R respiratory domain score. The selected predictors explained 23 % of the variability in sweat chloride concentration changes, 18 % of the variability in ppFEV1 changes, 39 % of the variability in BMI changes, and 65 % of the variability in CFQ-R changes.
CONCLUSIONS: This study highlights a high level of heterogeneity in treatment response to ETI, which can only be partially explained by the baseline characteristics of the disease.
PMID:38729849 | DOI:10.1016/j.jcf.2024.04.013
Inhaled antibiotics: A promising drug delivery strategies for efficient treatment of lower respiratory tract infections (LRTIs) associated with antibiotic resistant biofilm-dwelling and intracellular bacterial pathogens
Respir Med. 2024 May 8:107661. doi: 10.1016/j.rmed.2024.107661. Online ahead of print.
ABSTRACT
Antibiotic-resistant bacteria associated with LRTIs are frequently associated with inefficient treatment outcomes. Antibiotic-resistant Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas aeruginosa, and Staphylococcus aureus, infections are strongly associated with pulmonary exacerbations and require frequent hospital admissions, usually following failed management in the community. These bacteria are difficult to treat as they demonstrate multiple adaptational mechanisms including biofilm formation to resist antibiotic threats. Currently, many patients with the genetic disease cystic fibrosis (CF), non-CF bronchiectasis (NCFB) and chronic obstructive pulmonary disease (COPD) experience exacerbations of their lung disease and require high doses of systemically administered antibiotics to achieve meaningful clinical effects, but even with high systemic doses penetration of antibiotic into the site of infection within the lung is suboptimal. Pulmonary drug delivery technology that reliably deliver antibacterials directly into the infected cells of the lungs and penetrate bacterial biofilms to provide therapeutic doses with a greatly reduced risk of systemic adverse effects. Inhaled liposomal-packaged antibiotic with biofilm-dissolving drugs offer the opportunity for targeted, and highly effective antibacterial therapeutics in the lungs. Although the challenges with development of some inhaled antibiotics and their clinicals trials have been studied; however, only few inhaled products are available on market. This review addresses the current treatment challenges of antibiotic-resistant bacteria in the lung with some clinical outcomes and provides future directions with innovative ideas on new inhaled formulations and delivery technology that promise enhanced killing of antibiotic-resistant biofilm-dwelling bacteria.
PMID:38729529 | DOI:10.1016/j.rmed.2024.107661
Preclinical murine models for the testing of antimicrobials against Mycobacterium abscessus pulmonary infections: Current practices and recommendations
Tuberculosis (Edinb). 2024 Mar 19;147:102503. doi: 10.1016/j.tube.2024.102503. Online ahead of print.
ABSTRACT
Mycobacterium abscessus, a rapidly growing nontuberculous mycobacterium, is increasingly recognized as an important pathogen of the human lung, disproportionally affecting people with cystic fibrosis (CF) and other susceptible individuals with non-CF bronchiectasis and compromised immune functions. M. abscessus infections are extremely difficult to treat due to intrinsic resistance to many antibiotics, including most anti-tuberculous drugs. Current standard-of-care chemotherapy is long, includes multiple oral and parenteral repurposed drugs, and is associated with significant toxicity. The development of more effective oral antibiotics to treat M. abscessus infections has thus emerged as a high priority. While murine models have proven instrumental in predicting the efficacy of therapeutic treatments for M. tuberculosis infections, the preclinical evaluation of drugs against M. abscessus infections has proven more challenging due to the difficulty of establishing a progressive, sustained, pulmonary infection with this pathogen in mice. To address this issue, a series of three workshops were hosted in 2023 by the Cystic Fibrosis Foundation (CFF) and the National Institute of Allergy and Infectious Diseases (NIAID) to review the current murine models of M. abscessus infections, discuss current challenges and identify priorities toward establishing validated and globally harmonized preclinical models. This paper summarizes the key points from these workshops. The hope is that the recommendations that emerged from this exercise will facilitate the implementation of informative murine models of therapeutic efficacy testing across laboratories, improve reproducibility from lab-to-lab and accelerate preclinical-to-clinical translation.
PMID:38729070 | DOI:10.1016/j.tube.2024.102503
Itaconic acid inhibits nontuberculous mycobacterial growth in pH dependent manner while 4-octyl-itaconic acid enhances THP-1 clearance of nontuberculous mycobacteria in vitro
PLoS One. 2024 May 10;19(5):e0303516. doi: 10.1371/journal.pone.0303516. eCollection 2024.
ABSTRACT
Increasingly prevalent, nontuberculous mycobacteria (NTM) infections affect approximately 20% of people with cystic fibrosis (CF). Previous studies of CF sputum identified lower levels of the host metabolite itaconate in those infected with NTM. Itaconate can inhibit the growth of M. tuberculosis (MTB) in vitro via the inhibition of the glyoxylate cycle enzyme (ICL), but its impact on NTM is unclear. To test itaconic acid's (IA) effect on NTM growth, laboratory and CF clinical strains of Mycobacterium abscessus and Mycobacterium avium were cultured in 7H9 minimal media supplemented with 1-10 mM of IA and short-chain fatty acids (SCFA). M. avium and M. abscessus grew when supplemented with SCFAs, whereas the addition of IA (≥ 10 mM) completely inhibited NTM growth. NTM supplemented with acetate or propionate and 5 mM IA displayed slower growth than NTM cultured with SCFA and ≤ 1 mM of IA. However, IA's inhibition of NTM was pH dependent; as similar and higher quantities (100 mM) of pH adjusted IA (pH 7) did not inhibit growth in vitro, while in an acidic minimal media (pH 6.1), 1 to 5 mM of non-pH adjusted IA inhibited growth. None of the examined isolates displayed the ability to utilize IA as a carbon source, and IA added to M. abscessus isocitrate lyase (ICL) decreased enzymatic activity. Lastly, the addition of cell-permeable 4-octyl itaconate (4-OI) to THP-1 cells enhanced NTM clearance, demonstrating a potential role for IA/itaconate in host defense against NTM infections.
PMID:38728330 | DOI:10.1371/journal.pone.0303516
A national postgraduate nurse practitioner and physician assistant fellowship in cystic fibrosis: An innovative approach to the provider shortage in complex and rare disease
J Am Assoc Nurse Pract. 2024 May 10. doi: 10.1097/JXX.0000000000001021. Online ahead of print.
ABSTRACT
Cystic fibrosis (CF) is a complex life-limiting genetic condition that affects the respiratory, digestive, reproductive system, and sweat glands. Advances in treatment have led to improved survival and quality of life. Today, most persons with CF live to adulthood but require highly specialized care at accredited CF Care Centers. The growing and aging CF population combined with the provider workforce shortage have increased the demand for qualified CF providers. Nurse practitioners (NPs) and physician assistants (PAs) have been providing CF care for decades, but most learned on the job. The Leadership and Education for Advanced Practice Provider (LEAPP) fellowship in CF care aims to address the provider gap, ease transition to practice, and ensure access to specialized care. Unlike other institutional based joint NP/PA fellowships, LEAPP was designed to train providers at various locations across the national CF care center network. The program is innovative in several ways: (1) LEAPP employs a flipped classroom that pairs an online curriculum with case-based virtual discussion with content experts from the CF care network; (2) fellows receive mentored clinical training at their home CF center; (3) LEAPP partnered with a university-based team to ensure best practices and evaluation for adult learners; and (4) LEAPP promotes organizational enculturation through program components of professional mentoring, quality improvement, and leadership. This innovative approach may be suitable for other complex conditions that require highly specialized care, such as sickle cell disease, spina bifida, and solid organ transplant.
PMID:38727543 | DOI:10.1097/JXX.0000000000001021
What makes a temperate phage an effective bacterial weapon?
mSystems. 2024 May 10:e0103623. doi: 10.1128/msystems.01036-23. Online ahead of print.
ABSTRACT
Temperate bacteriophages (phages) are common features of bacterial genomes and can act as self-amplifying biological weapons, killing susceptible competitors and thus increasing the fitness of their bacterial hosts (lysogens). Despite their prevalence, however, the key characteristics of an effective temperate phage weapon remain unclear. Here, we use systematic mathematical analyses coupled with experimental tests to understand what makes an effective temperate phage weapon. We find that effectiveness is controlled by phage life history traits-in particular, the probability of lysis and induction rate-but that the optimal combination of traits varies with the initial frequency of a lysogen within a population. As a consequence, certain phage weapons can be detrimental when their hosts are rare yet beneficial when their hosts are common, while subtle changes in individual life history traits can completely reverse the impact of an individual phage weapon on lysogen fitness. We confirm key predictions of our model experimentally, using temperate phages isolated from the clinically relevant Liverpool epidemic strain of Pseudomonas aeruginosa. Through these experiments, we further demonstrate that nutrient availability can also play a critical role in driving frequency-dependent patterns in phage-mediated competition. Together, these findings highlight the complex and context-dependent nature of temperate phage weapons and the importance of both ecological and evolutionary processes in shaping microbial community dynamics more broadly.
IMPORTANCE: Temperate bacteriophages-viruses that integrate within bacterial DNA-are incredibly common within bacterial genomes and can act as powerful self-amplifying weapons. Bacterial hosts that carry temperate bacteriophages can thus gain a fitness advantage within a given niche by killing competitors. But what makes an effective phage weapon? Here, we first use a simple mathematical model to explore the factors determining bacteriophage weapon utility. Our models suggest that bacteriophage weapons are nuanced and context-dependent; an individual bacteriophage may be beneficial or costly depending upon tiny changes to how it behaves or the bacterial community it inhabits. We then confirm these mathematical predictions experimentally, using phages isolated from cystic fibrosis patients. But, in doing so, we also find that another factor-nutrient availability-plays a key role in shaping bacteriophage-mediated competition. Together, our results provide new insights into how temperate bacteriophages modulate bacterial communities.
PMID:38727217 | DOI:10.1128/msystems.01036-23
Phase 1b study of batiraxcept in combination with durvalumab in patients with platinum-resistant ovarian cancer
iScience. 2024 Apr 23;27(5):109801. doi: 10.1016/j.isci.2024.109801. eCollection 2024 May 17.
ABSTRACT
Combining an immune checkpoint inhibitor with batiraxcept (AVB-S6-500), an AXL inhibitor that acts via selective binding to growth arrest-specific protein 6 (GAS6), may improve anti-tumor immunity in platinum-resistant ovarian cancer (PROC). This phase 1b trial of durvalumab in combination with escalating doses of batiraxcept enrolled patients with recurrent PROC (NCT04019288). The primary objective was to determine the toxicity profile of the combination. Eleven patients were enrolled on the trial. No dose-limiting toxicities were observed, and no objective responses were noted. Median progression free survival (PFS) was 1.81 months (95% confidence interval (CI) 1.71-2.40), and median overall survival (OS) was 4.53 months (95% CI 2.10-24.74). Batiraxcept effectively reduced serum GAS6 levels at 1-h post-treatment, resulting in trough levels below the limit of detection in all cases but one. In conclusion, the combination of batiraxcept and durvalumab was safe and tolerable but did not demonstrate anti-tumor activity in a heterogenous population of patients with recurrent PROC.
PMID:38726365 | PMC:PMC11079458 | DOI:10.1016/j.isci.2024.109801