Pulmonary Disease Burden in Primary Immune Deficiency Disorders: Data from USIDNET Registry.

J Clin Immunol. 2020 Jan 09;:

Authors: Patrawala M, Cui Y, Peng L, Fuleihan RL, Garabedian EK, Patel K, Guglani L

Abstract
PURPOSE: Pulmonary manifestations are common in patients with primary immunodeficiency disorders (PIDs) but the prevalence, specific diseases, and their patterns are not well characterized.
METHODS: We conducted a retrospective analysis of pulmonary diseases reported in the database of the United States Immunodeficiency Network (USIDNET), a program of the Immune Deficiency Foundation. PIDs were categorized into 10 groups and their demographics, pulmonary diagnoses and procedures, infections, prophylaxis regimens, and laboratory findings were analyzed.
RESULTS: A total of 1937 patients with various PIDs (39.3% of total patients, 49.6% male, average age 37.9 years (SD = 22.4 years)) were noted to have a pulmonary disease comorbidity. Pulmonary diseases were categorized into broad categories: airway (86.8%), parenchymal (18.5%), pleural (4.6%), vascular (4.3%), and other (13.9%) disorders. Common variable immune deficiency (CVID) accounted for almost half of PIDs associated with airway, parenchymal, and other pulmonary disorders. Pulmonary procedures performed in 392 patients were mostly diagnostic (77.3%) or therapeutic (16.3%). These patients were receiving a wide variety of treatments, which included immunoglobulin replacement (82.1%), immunosuppressive (32.2%), anti-inflammatory (12.7%), biologic (9.3%), and cytokine (7.6%)-based therapies. Prophylactic therapy was being given with antibiotics (18.1%), antifungal (3.3%), and antiviral (2.2%) medications, and 7.1% of patients were on long-term oxygen therapy due to advanced lung disease.
CONCLUSIONS: Pulmonary manifestations are common in individuals with PID, but long-term pulmonary outcomes are not well known in this group of patients. Further longitudinal follow-up will help to define long-term prognosis of respiratory comorbidities and optimal treatment modalities.

PMID: 31919711 [PubMed - as supplied by publisher]

Association of Serum TGF-β1 Levels with Different Clinical Phenotypes of Cystic Fibrosis Exacerbation.

Lung. 2020 Jan 09;:

Authors: Sagwal S, Chauhan A, Kaur J, Prasad R, Singh M, Singh M

Abstract
PURPOSE: Cystic Fibrosis (CF) is a multi-organ genetic disorder and Transforming Growth Factor (TGF-β1) is a modifier gene which modulates lung pathology in CF. There is great phenotypic variability among CF patients who even have similar genotype. The aim of the present study was to associate the serum levels of TGF-β1 with several clinical phenotypes of CF.
METHODS: The diagnosed cases of CF were recruited and the blood sample was withdrawn at different time points: during exacerbation (n = 26), non-exacerbation (n = 9) and after antibiotic therapy (n = 11). The concentration of the total TGF-β1 in serum was measured with commercial ELISA kit. The ΔF508 mutation was assessed by the Amplification Refractory Mutation System (ARMS-PCR).
RESULTS: The levels of TGF-β1 were increased in exacerbation phase (119.89 ± 29.64 ng/mL), infection with P. aeruginosa (121.8 ± 28.83 ng/mL) and in subjects with ΔF508 mutation (139.2 ± 19.59 ng/mL). The levels of TGF-β1 in CF patients with Allergic Bronchopulmonary Aspergillosis (ABPA) (109.97 ± 27.71 ng/mL) were decreased as compared to CF patients without ABPA (123.55 ± 30.20 ng/mL). It was observed that the serum levels of TGF-β1 were decreased significantly after antibiotic therapy (p < 0.05).
CONCLUSIONS: The present study has determined that the serum levels of TGF-β1 vary with the type of infections, ΔF508 CFTR mutation, presence of ABPA and response to therapy.

PMID: 31919585 [PubMed - as supplied by publisher]

Reply.

Pediatr Pulmonol. 2019 09;54(9):1354-1355

Authors: Donadio MVF, Vendrusculo FM

PMID: 31190474 [PubMed - indexed for MEDLINE]

Developing a smartphone application to support social connectedness and wellbeing in young people with cystic fibrosis.

J Cyst Fibros. 2020 Jan 06;:

Authors: Francis J, Cross D, Schultz A, Armstrong D, Nguyen R, Branch-Smith C

Abstract
BACKGROUND: Young people with cystic fibrosis (CF) may be at increased risk of social isolation and mental illness. This study aimed to design and evaluate the usability and acceptability of a smartphone application (app) to support the social connectedness and wellbeing of young people living with CF.
METHODS: Young people with CF aged 12-17 years (N = 22) were recruited from two paediatric hospitals in Australia. Study participants tested the CF app for six weeks before responding to an online survey about the app's usability and acceptability. A subsample of participants (n = 20) discussed the app's strengths and weaknesses during 11 online group interviews.
RESULTS: During the six-week testing period, 77% of participants used the app at least once a week and 82% accessed the app from a smartphone. Usability of the CF app was rated high. Most participants agreed the app was easy to use (86%) and felt comfortable using it (96%). Acceptability of the app was moderate. 77% of participants agreed they would recommend the app to others. Recommendations to improve the app's functionality and acceptability included locating the chatroom within the app rather than redirecting users to a web browser and allowing users to personalise images, wellness tips and videos.
CONCLUSIONS: This study developed and tested a highly usable, and moderately acceptable, smartphone app to improve the psychosocial health of young people living with CF. Future research will test the efficacy of the CF app on users' social connectedness and wellbeing.

PMID: 31917112 [PubMed - as supplied by publisher]

Phenotype of children with inconclusive cystic fibrosis diagnosis after newborn screening.

Pediatr Pulmonol. 2020 Jan 09;:

Authors: Munck A, Bourmaud A, Bellon G, Picq P, Farrell PM, DPAM Study Group

Abstract
OBJECTIVE: To characterize the phenotypic expression of children with conductance regulator-related metabolic syndrome (CRMS)/cystic fibrosis screen positive inconclusive diagnosis (CFSPID) designation after positive newborn screening, reassign labeling if applicable and better define these children's prognosis.
METHODS: A multicenter cohort with CRMS/CFSPID designation was matched with cystic fibrosis (CF)-diagnosed cohort. Cohorts were prospectively compared on baseline characteristics, cumulative data and when they reached 6 to 7 years at endpoint assessment.
RESULTS: Compared to infants with CF (n = 63), the CRMS/CFSPID cohort (n = 63) had initially lower immunoreactive trypsinogen (IRT) and sweat chloride (SC) values, delayed visits, less symptoms, and better nutritional status; during follow-up, they had fewer hospitalizations, Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus identification, CF comorbidities, and treatment burden. At endpoint assessment, they presented a milder pulmonary phenotype on Brody computed tomography scores (0.0[0.0; 2.0] vs 13[2.0; 31.0]; P < .0001, respectively), Wisconsin and Brasfield chest radiograph scores, pulmonary function tests, and improved nutritional status. Among the inconclusive CF diagnosis cohort, 28 cases (44%) converted to CF diagnosis based on genotype (44%), SC (28%) or both (28%); yet, comparing those with or without final CF diagnosis, we found no differences, possibly related to their young age and mild degree of lung disease. In the total cohort, we found significant associations between Brody scores and IRT, SC values, genotype, Wisconsin and Brasfield score and spirometry.
CONCLUSIONS: The matched CRMS/CFSPID and CF cohorts showed differences in outcomes. By a mean age of 7.6 years, a high proportion of the CRMS/CFSPID cohort converted to CF. Our results highlight that monitoring at CF clinics until at least 6 years is needed as well as further studies.

PMID: 31916691 [PubMed - as supplied by publisher]

Molecular epidemiology of Aspergillus species and other moulds in respiratory samples from Argentinean patients with cystic fibrosis.

Med Mycol. 2020 Jan 08;:

Authors: Devoto TB, Alava KSH, Pola SJ, Pereda R, Rubeglio E, Finquelievich JL, Cuestas ML

Abstract
In cystic fibrosis (CF) patients, fungal colonization of the respiratory tract is frequently found. Aspergillus fumigatus is the most frequently recorded and is associated with loss of pulmonary function and allergic disease (ABPA). The knowledge on prevalence rates of filamentous fungi in CF patients in Latin America is scarce. One hundred and seventy-six fungal isolates recovered from the upper respiratory tract of CF patients from Argentina were identified to species by morphology and DNA sequencing. In total, 90% of CF patients were colonized by Aspergillus sp., followed by Exophiala sp. (14%) and Scedosporium sp. (10%). Among Aspergillus, six species complexes (Fumigati, Flavi, Terrei, Nigri, Usti, and Nidulante) and different cryptospecies were found. Among Scedosporium, three species were observed (Scedosporium apiospermum, Scedosporium aurantiacum and Scedosporium boydii). All Exophiala isolates were identified as Exophiala dermatitidis. Rare filamentous fungi were also found. All cases of ABPA were associated to the presence of A. fumigatus. Mixed colonization with other mould or rare fungi was observed in half of them. To our knowledge, this is the first prospective study of mould species in CF using molecular methods in Latin America. This study shows that Aspergillus sp., E. dermatitidis and Scedosporium sp. have a high frequency in CF patients from Argentina, and by far, A. fumigatus was the most commonly cultured species. Continuous clinical surveillance is required to detect the emergence of new fungal pathogens and to detect resistant or difficult-to-treat species capable of chronic colonizing the airways and of hematogenous dissemination in case of lung transplantation.

PMID: 31915834 [PubMed - as supplied by publisher]

An antimicrobial molecule mitigates signs of sepsis in vivo and eradicates infections from lung tissue.

FASEB J. 2020 Jan;34(1):192-207

Authors: Quercini L, Brunetti J, Riolo G, Bindi S, Scali S, Lampronti I, D'Aversa E, Wronski S, Pollini S, Gentile M, Lupetti P, Rossolini GM, Falciani C, Bracci L, Pini A

Abstract
The peptide sequence KKIRVRLSA was synthesized in a dimeric structure (SET-M33DIM) and evaluated as a candidate drug for infections due to multidrug-resistant (MDR) Gram-negative pathogens. SET-M33DIM showed significant antibacterial activity against MDR strains of Klebsiella pneumoniae, Acinetobacter baumannii, and Escherichia coli (Minimal Inhibitory Concentration [MICs], 1.5-11 µM), and less activity against Pseudomonas aeruginosa (MICs, 11-22 µM). It showed very low toxicity in vitro, ex vivo, and in vivo; in cytotoxicity tests, its EC50 was as much as 22 times better than that of SET-M33, a peptide with the same amino-acid sequence, but synthesized in tetra-branched form (638 vs 28 µM). In in vivo and ex vivo experiments, SET-M33DIM cleared P. aeruginosa infection, significantly reducing signs of sepsis in animals, and restoring cell viability in lung tissue after bacterial challenge. It also quelled inflammation triggered by LPS and live bacterial cells, inhibiting expression of inflammatory mediators in lung tissue, cultured macrophages, and bronchial cells from a cystic fibrosis patient.

PMID: 31914681 [PubMed - in process]

Proliferation of adult human bronchial epithelial cells without a telomere maintenance mechanism for over 200 population doublings.

FASEB J. 2020 Jan;34(1):386-398

Authors: Peters-Hall JR, Min J, Tedone E, Sho S, Siteni S, Mender I, Shay JW

Abstract
To date, there is no direct evidence of telomerase activity in adult lung epithelial cells, but typical culture conditions only support cell proliferation for 30-40 population doublings (PD), a point at which telomeres remain relatively long. Here we report that in in vitro low stress culture conditions consisting of a fibroblast feeder layer, rho-associated coiled coil protein kinase inhibitor (ROCKi), and low oxygen (2%), normal human bronchial epithelial basal progenitor cells (HBECs) divide for over 200 PD without engaging a telomere maintenance mechanism (almost four times the "Hayflick limit"). HBECs exhibit critically short telomeres at 200 PD and the population of cells start to undergo replicative senescence. Subcloning these late passage cells to clonal density, to mimic lung injury in vivo, selects for rare subsets of HBECs that activate low levels of telomerase activity to maintain short telomeres. CRISPR/Cas9 knockout of human telomerase reverse transcriptase or treatment with the telomerase-mediated telomere targeting agent 6-thio-2'deoxyguanosine abrogates colony growth in these late passage cultures (>200 PD) but not in early passage cultures (<200 PD). To our knowledge, this is the first study to report such long-term growth of HBECs without a telomere maintenance mechanism. This report also provides direct evidence of telomerase activation in HBECs near senescence when telomeres are critically short. This novel cell culture system provides an experimental model to understand how telomerase is regulated in normal adult tissues.

PMID: 31914653 [PubMed - in process]

Roles of FtsEX in cell division.

Res Microbiol. 2019 Nov - Dec;170(8):374-380

Authors: Pichoff S, Du S, Lutkenhaus J

Abstract
FtsEX is a member of a small subclass of ABC transporters that uses mechano-transmission to perform work in the periplasm. FtsEX controls periplasmic peptidoglycan (PG) hydrolase activities in many Gram negative and positive organisms to ensure the safe separation of daughter cells during division. In these organisms FtsEX localizes to the Z ring and uses its ATPase activity to regulate its periplasmic effectors. In Escherichia coli, FtsEX also participates in building the divisome and coordinates PG synthesis with PG hydrolysis. This review discusses studies that are beginning to elucidate the mechanisms of FtsEX's various roles in cell division.

PMID: 31376483 [PubMed - indexed for MEDLINE]

Predictors of non-cystic fibrosis bronchiectasis in Indigenous adult residents of central Australia: results of a case-control study.

ERJ Open Res. 2019 Oct;5(4):

Authors: Einsiedel L, Pham H, Au V, Hatami S, Wilson K, Spelman T, Jersmann H

Abstract
The human T-cell leukaemia virus type 1 (HTLV-1) is associated with pulmonary inflammation. Indigenous Australians in central Australia have a very high prevalence of HTLV-1 infection and we hypothesised that this might contribute to high rates of bronchiectasis in this population. 80 Indigenous adults with confirmed bronchiectasis, each matched by age, sex and language to two controls without bronchiectasis, were recruited. Case notes and chest imaging were reviewed, HTLV-1 serology and the number of peripheral blood leukocytes (PBLs) infected with HTLV-1 (pro-viral load (PVL)) were determined, and radiological abnormality scores were calculated. Participants were followed for a mean±sd of 1.14±0.86 years and causes of death were determined. Median (interquartile range) HTLV-1 PVL for cases was 8-fold higher than controls (cases 213.8 (19.7-3776.3) copies per 105 PBLs versus controls 26.6 (0.9-361) copies per 105 PBLs; p=0.002). Radiological abnormality scores were higher for cases with HTLV-1 PVL ≥1000 copies per 105 PBLs and no cause of bronchiectasis other than HTLV-1 infection. Major predictors of bronchiectasis were prior severe lower respiratory tract infection (adjusted OR (aOR) 17.83, 95% CI 4.51-70.49; p<0.001) and an HTLV-1 PVL ≥1000 copies per 105 PBLs (aOR 12.41, 95% CI 3.84-40.15; p<0.001). Bronchiectasis (aOR 4.27, 95% CI 2.04-8.94; p<0.001) and HTLV-1 PVL ≥1000 copies per 105 PBLs (aOR 3.69, 95% CI 1.11-12.27; p=0.033) predicted death. High HTLV-1 PVLs are associated with bronchiectasis and with more extensive radiological abnormalities, which may result from HTLV-1-mediated airway inflammation.

PMID: 31911928 [PubMed]

High Mobility Group Box-1 Increases Epithelial Sodium Channel Activity and Inflammation via the Receptor for Advanced Glycation End Products.

Am J Physiol Cell Physiol. 2020 Jan 08;:

Authors: Grant GJ, Liou TG, Paine R, Helms MN

Abstract
Cystic fibrosis (CF) lung disease persists and remains life-limiting for many patients. Elevated high mobility group box-1 protein (HMGB-1) levels and hyperactive epithelial sodium channel activity (ENaC) are hallmark features of the CF lung. The objective of this study was to better understand the pathogenic role of HMGB-1 signaling and ENaC in CF airway cells. We hypothesize that HMGB-1 links airway inflammation (via signaling to the receptor for advanced glycation end products; RAGE) and airway surface liquid dehydration (via up-regulating ENaC) in the CF lung. We calculated equivalent short current (Isc) and single channel ENaC open probability (Po) in normal and CF human small airway epithelial cells (SAEC) ± human HMGB-1 peptide (0.5 μg/mL). In normal SAECs, HMGB-1 increased amiloride-sensitive Isc and ENaC Po from 0.15±0.03 to 0.28±0.04; p<0.01. In CF SAECs, ENaC Po increased from 0.45±0.06 to 0.73±0.04; p<0.01. Pretreatment with 1 μM FPS-ZM1 (RAGE inhibitor) attenuated all HMGB-1 effects on ENaC current in normal and CF SAEC. Confocal analysis of SAECs indicate that nuclear size and HMBG-1 localization can be impacted by ENaC dysfunction. Masson's trichrome labeling of mouse lung showed that IP injected HMGB-1 significantly increased pulmonary fibrosis. Bronchoalveolar lavage fluid from HMGB-1 treated mice showed significant increases in IL-1β, IL-10, IL-6, IL-27, IL-17A, IFN-β, and GM-CSF over vehicle injected mice; p<0.05. These studies put forth a new model in which HMGB-1 signaling to RAGE plays an important role in perpetuating lung ENaC dysfunction and inflammation in the CF lung.

PMID: 31913693 [PubMed - as supplied by publisher]

TMEM16A Potentiators: Is There a Need for New Modulators in Cystic Fibrosis?

Am J Respir Crit Care Med. 2020 Jan 08;:

Authors: Kim MD, Salathe M

PMID: 31913655 [PubMed - as supplied by publisher]

Evaluating sequence data quality from the Swift Accel-Amplicon CFTR Panel.

Sci Data. 2020 Jan 08;7(1):8

Authors: Leung ML, Watson DJ, Vaccaro CN, Mafra F, Wenocur A, Wang T, Hakonarson H, Santani A

Abstract
Cystic fibrosis (CF) is one of the most common genetic diseases worldwide with high carrier frequencies across different ethnicities. Next generation sequencing of the cystic fibrosis transmembrane conductance regulator (CFTR) gene has proven to be an effective screening tool to determine carrier status with high detection rates. Here, we evaluate the performance of the Swift Biosciences Accel-Amplicon CFTR Capture Panel using CFTR-positive DNA samples. This assay is a one-day protocol that allows for one-tube reaction of 87 amplicons that span all coding regions, 5' and 3'UTR, as well as four intronic regions. In this study, we provide the FASTQ, BAM, and VCF files on seven unique CFTR-positive samples and one normal control sample (14 samples processed including repeated samples). This method generated sequencing data with high coverage and near 100% on-target reads. We found that coverage depth was correlated with the GC content of each exon. This dataset is instrumental for clinical laboratories that are evaluating this technology as part of their carrier screening program.

PMID: 31913291 [PubMed - in process]

Clinical burden of severe respiratory syncytial virus infection during the first 2 years of life in children born between 2000 and 2011 in Scotland.

Eur J Pediatr. 2020 Jan 07;:

Authors: Thwaites R, Buchan S, Fullarton J, Morris C, Grubb E, Rodgers-Gray B, Coutts J

Abstract
National data from Scotland (all births from 2000 to 2011) were used to estimate the burden associated with respiratory syncytial virus hospitalisation (RSVH) during the first 2 years of life. RSVHs were identified using the International Classification of Diseases 10th Revision codes. Of 623,770 children, 13,362 (2.1%) had ≥ 1 RSVH by 2 years, with the overall rate being 27.2/1000 (16,946 total RSVHs). Median age at first RSVH was 137 days (interquartile range [IQR] 62-264), with 84.3% of admissions occurring by 1 year. Median length of stay was 2 (IQR 1-4) days and intensive care unit (ICU) admission was required by 4.3% (727) for a median 5 (IQR 2-8) days. RSVHs accounted for 6.9% (5089/73,525) of ICU bed days and 6.2% (64,395/1,033,121) of overall bed days (5370/year). RSVHs represented 8.5% (14,243/168,205) of all admissions between October and March and 14.2% (8470/59,535) between December and January. RSVH incidence ranged from 1.7 to 2.5%/year over the study period. Preterms (RSVH incidence 5.2%), and those with congenital heart disease (10.5%), congenital lung disease (11.2%), Down syndrome (14.8%), cerebral palsy (15.5%), cystic fibrosis (12.6%), and neuromuscular disorders (17.0%) were at increased risk of RSVH.Conclusions: RSV causes a substantial burden on Scottish paediatric services during the winter months.What is known:• Respiratory syncytial virus (RSV) is a leading cause of childhood hospitalisation.What is new:• This 12-year study is the first to estimate the burden of RSV hospitalisation (RSVH) in Scotland and included all live births from 2000 to 2011 and followed > 600,000 children until 2 years old.• The overall RSVH rate was 27.2/1000 children, with 2.1% being hospitalised ≥ 1 times.• RSVHs accounted for 6.2% of all inpatient bed days, which rose to 14.2% during the peak months of the RSV season (December-January), equating to over 1400 hospitalisations and nearly 5500 bed days each year.

PMID: 31912234 [PubMed - as supplied by publisher]

Targeting Muscles in the Brain to Enhance Cerebral Perfusion.

JACC Basic Transl Sci. 2019 Dec;4(8):959-961

Authors: Lee JM, Diwan A, Zipfel GJ

PMID: 31909771 [PubMed]

CFTR Therapeutics Normalize Cerebral Perfusion Deficits in Mouse Models of Heart Failure and Subarachnoid Hemorrhage.

JACC Basic Transl Sci. 2019 Dec;4(8):940-958

Authors: Lidington D, Fares JC, Uhl FE, Dinh DD, Kroetsch JT, Sauvé M, Malik FA, Matthes F, Vanherle L, Adel A, Momen A, Zhang H, Aschar-Sobbi R, Foltz WD, Wan H, Sumiyoshi M, Macdonald RL, Husain M, Backx PH, Heximer SP, Meissner A, Bolz SS

Abstract
Heart failure (HF) and subarachnoid hemorrhage (SAH) chronically reduce cerebral perfusion, which negatively affects clinical outcome. This work demonstrates a strong relationship between cerebral artery cystic fibrosis transmembrane conductance regulator (CFTR) expression and altered cerebrovascular reactivity in HF and SAH. In HF and SAH, CFTR corrector compounds (C18 or lumacaftor) normalize pathological alterations in cerebral artery CFTR expression, vascular reactivity, and cerebral perfusion, without affecting systemic hemodynamic parameters. This normalization correlates with reduced neuronal injury. Therefore, CFTR therapeutics have emerged as valuable clinical tools to manage cerebrovascular dysfunction, impaired cerebral perfusion, and neuronal injury.

PMID: 31909302 [PubMed]

Changes in Clinical Markers During A Short-Term Transfer Program of Adult Cystic Fibrosis Patients from Pediatric to Adult Care.

Open Respir Med J. 2019;13:11-18

Authors: Welsner M, Sutharsan S, Taube C, Olivier M, Mellies U, Stehling F

Abstract
Background: Transition from child-oriented to adult-oriented health care in Cystic Fibrosis (CF) has become more important over recent decades as the survival of people with this disease has increased. The transition process usually begins in adolescence, with full transfer completed in early adulthood.
Objective: This study investigated the impact of a short-term transfer program on clinical markers in an adult CF cohort still being managed by pediatricians.
Methods: Clinically relevant data from the year before (T-1), the time of Transfer (T) and the year after the transfer (T+1) were analysed retrospectively.
Results: 39 patients (median age 29.0 years; 64% male) were transferred between February and December 2016. Lung function had declined significantly in the year before transfer (in % predicted: Forced Expiratory Volume in 1 second (FEV), 62.8 vs. 57.7, p <0.05; Forced Vital Capacity (FVC), 79.9 vs. 71.1, p<0.05), but remained stable in the year after transfer (in % predicted: FEV: 56.3; FVC 68.2). BMI was stable over the whole observational period. There was no relevant change in chronic lung infection with P. aeruginosa, Methicillin-Resistant Staphylococcus aureus (MRSA) and Burkholderia sp. during the observation period. The number of patient contacts increased significantly in the year after versus the year before transfer (inpatient: 1.51 vs. 2.51, p<0.05; outpatient: 2.67 vs. 3.41, p<0.05).
Conclusions: Our data show that, within the framework of a structured transfer process, it is possible to transfer a large number of adult CF patients, outside a classic transition program, from a pediatric to an adult CF center in a short period of time, without any relevant changes in clinical markers and, stability.

PMID: 31908684 [PubMed]

Clonal Diversity, Biofilm Formation, and Antimicrobial Resistance among Stenotrophomonas maltophilia Strains from Cystic Fibrosis and Non-Cystic Fibrosis Patients.

Antibiotics (Basel). 2020 Jan 02;9(1):

Authors: Pompilio A, Savini V, Fiscarelli E, Gherardi G, Di Bonaventura G

Abstract
The intrinsic antibiotic resistance of Stenotrophomonas maltophilia, along with its ability to form biofilm both on abiotic surfaces and host tissues, dramatically affects the efficacy of the antibiotic therapy. In this work, 85 S. maltophilia strains isolated in several hospital of central Italy and from several clinical settings were evaluated for their genetic relatedness (by pulsed-field gel electrophoresis, PFGE), biofilm formation (by microtiter plate assay), and planktonic antibiotic resistance (by Kirby-Bauer disk diffusion technique). The S. maltophilia population showed a high genetic heterogeneity: 64 different PFGE types were identified, equally distributed in cystic fibrosis (CF) and non-CF strains, and some consisted of multiple strains. Most of the strains (88.2%) were able to form biofilm, although non-CF strains were significantly more efficient than CF strains. CF strains produced lower biofilm amounts than non-CF strains, both those from respiratory tracts and blood. Non-CF PFGE types 3 and 27 consisted of strong-producers only. Cotrimoxazole and levofloxacin were the most effective antibiotics, being active respectively against 81.2% and 72.9% of strains. CF strains were significantly more resistant to piperacillin/tazobactam compared to non-CF strains (90% versus 53.3%), regardless of sample type. Among respiratory strains, cotrimoxazole was more active against non-CF than CF strains (susceptibility rates: 86.7% versus 75%). The multidrug resistant phenotype was significantly more prevalent in CF than non-CF strains (90% versus 66.7%). Overall, the multidrug-resistance level was negatively associated with efficiency in biofilm formation. Our results showed, for the first time, that in S. maltophilia both classical planktonic drug resistance and the ability of biofilm formation might favor its dissemination in the hospital setting. Biofilm formation might in fact act as a survival mechanism for susceptible bacteria, suggesting that clinical isolates should be routinely assayed for biofilm formation in diagnostic laboratories.

PMID: 31906465 [PubMed]

Gradual adaptation of facultative anaerobic pathogens to microaerobic and anaerobic conditions.

FASEB J. 2019 Dec 27;:

Authors: Pedraz L, Blanco-Cabra N, Torrents E

Abstract
Many notable human pathogens are facultative anaerobes. These pathogens exhibit redundant metabolic pathways and a whole array of regulatory systems to adapt to changing oxygen levels. However, our knowledge of facultative anaerobic pathogens is mostly based on fully aerobic or anaerobic cultures, which does not reflect real infection conditions, while the microaerobic range remains understudied. Here, we examine the behavior of pathogenic and nonpathogenic strains of two facultative anaerobes, Escherichia coli and Pseudomonas aeruginosa, during the aerobic-anaerobic transition. To do so, we introduce a new technique named AnaeroTrans, in which we allow self-consumption of oxygen by steady-state cultures and monitor the system by measuring the gas-phase oxygen concentration. We explore the different behavior of the studied species toward oxygen and examine how this behavior is associated with the targeted infection sites. As a model, we characterize the adaptation profile of the ribonucleotide reductase network, a complex oxygen-dependent enzymatic system responsible for the generation of the deoxyribonucleotides. We also explore the actions of the most important anaerobic regulators and how these regulators influence bacterial fitness. Our results allow us to classify the different elements that compose the aerobic-anaerobic transition into reproducible stages, thus showing the different adaptation mechanisms of the studied species.

PMID: 31908067 [PubMed - as supplied by publisher]

Oxidative Stress Influences Pseudomonas aeruginosa Susceptibility to Antibiotics and Reduces Its Pathogenesis in Host.

Curr Microbiol. 2020 Jan 07;:

Authors: Mohamed FA, Shaker GH, Askoura MM

Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes serious infections in humans, notably cystic fibrosis. P. aeruginosa faces various stresses such as oxidative stress either in the environment or within the host during infection. In the present study, the influence of oxidative stress on both Pseudomonas antibiotic susceptibility and host pathogenesis was characterized. Prior exposure to H2O2 significantly altered P. aeruginosa susceptibility to tested antibiotics; colistin, ciprofloxacin, tobramycin, and ceftazidime. The minimum inhibitory concentrations (MICs) of tested antibiotics either increased or decreased following H2O2 exposure. Importantly, RT-qPCR revealed that expression of quorum sensing genes, that regulate virulence factors production in P. aeruginosa, was significantly higher in unstressed relative to H2O2-stressed cells. The impact of P. aeruginosa exposure to oxidative stress by H2O2 on bacterial pathogenesis was investigated using in vivo mice infection model. Interestingly, exposure to oxidative stress markedly reduces P. aeruginosa pathogenesis in mice. Unstressed P. aeruginosa was able to kill more mice as compared to H2O2-stressed bacteria. In addition, body weight of mice infected with unstressed P. aeruginosa was lower than that of mice inoculated with stressed bacteria. Isolated organs (spleen, liver, and kidney) from mice infected with unstressed bacteria exhibited increased weight as well as bacterial load in comparison with mice infected with stressed bacteria. In summary, current data highlight the impact of oxidative stress on P. aeruginosa antibiotic susceptibility as well as host pathogenesis. These findings could be helpful in treatment of infections caused by this important pathogen.

PMID: 31907601 [PubMed - as supplied by publisher]