Gut bacterium Burkholderia cepacia (BsNLG8) and immune gene Defensin A contribute to the resistance against Nicotine-induced stress in Nilaparvata lugens (Stål).

Nicotine, a naturally occurring alkaloid found in tobacco, is a potent neurotoxin extensively used to control Nilaparvata lugens (Stål), a destructive insect pest of rice crops. The insect gut harbors a wide array of resident microorganisms that profoundly influence several biological processes, including host immunity. Maintaining an optimal gut microbiota and immune homeostasis requires a complex network of reciprocal regulatory interactions. However, the underlying molecular mechanisms driving these symbiotic exchanges, particularly between specific gut microbe and immunity, remain largely unknown in insects. Our previous investigations identified and isolated a nicotine-degrading Burkholderia cepacia strain (BsNLG8) with antifungal properties. Building on those findings, we found that nicotine intake significantly increased the abundance of a symbiotic bacteria BsNLG8, induced a stronger bacteriostatic effect in hemolymph, and enhanced the nicotine tolerance of N. lugens. Additionally, nicotine-induced antimicrobial peptides (AMPs) exhibited significant antibacterial effects against Staphylococcus aureus. We adopted RNA-seq to explore the underlying immunological mechanisms in nicotine-stressed N. lugens. Bioinformatic analyses identified numerous differentially expressed immune genes, including recognition/immune activation (GRPs and Toll) and AMPs (i.e., Defensin, Lugensin, lysozyme). Temporal expression profiling (12, 24, and 48 hours) of immune genes revealed pattern recognition proteins and immune effectors as primary responders to nicotine-induced stress. Defensin A, a broad-spectrum immunomodulatory cationic peptide, exhibited significantly high expression. RNA interference-mediated silencing of Defensin A reduced the survival, enhanced nicotine sensitivity of N. lugens to nicotine, and decreased the abundance of BsNLG8. The reintroduction of BsNLG8 improved the expression of immune genes, aiding nicotine resistance of N. lugens. Our findings indicate a potential reciprocal immunomodulatory interaction between Defensin A and BsNLG8 under nicotine stress. Moreover, this study offers novel and valuable insights for future research into enhancing nicotine-based pest management programs and developing alternative biocontrol methods involving the implication of insect symbionts.

Safety of continuous 12-hour delivery of antimicrobial doses of inhaled nitric oxide during ex vivo lung perfusion.

INTRODUCTION: High-dose nitric oxide (NO) has been shown effective against a variety of micro-organisms in vitro, including common bacteria found in donor organs. However, clinical obstacles related to its implementation in vivo are the formation of methemoglobin and the accumulation of toxic nitrogen compounds. Ex vivo lung perfusion (EVLP) is a platform that allows for organ maintenance with an acellular perfusion solution, thus overcoming these limitations. The present study explores the safety of continuous high-dose inhaled (iNO) during EVLP for an extended period of 12 hours. METHODS: Lungs procured from Yorkshire pigs were randomized into control (standard ventilation) and treatment (standard ventilation + 200 ppm iNO) groups, then perfused with an acellular solution for 12 hours (n = 4/group). Lung physiology and biological markers were evaluated. RESULTS: After 12 hours of either standard EVLP or EVLP + 200 ppm iNO, we did not notice any significant physiologic difference between the groups: pulmonary oxygenation (P = .586), peak airway pressures (P = .998), and dynamic (P = .997) and static (P = .908) lung compliances. In addition, no significant differences were seen among proinflammatory cytokines measured in perfusate and lung tissue. Importantly, most common toxic compounds were kept at safe levels throughout the treatment course. CONCLUSIONS: High-dose inhaled NO delivered continuously over 12 hours appears to be safe without inducing any significant pulmonary inflammation or deterioration in lung function. These findings support further efficacy studies to explore the use of iNO for the treatment of infections in donor lungs during EVLP.

Trends and correlation between antibacterial consumption and carbapenem resistance in gram-negative bacteria in a tertiary hospital in China from 2012 to 2019.

BACKGROUND: To investigate the trends and correlation between antibacterial consumption and carbapenem resistance in Gram-negative bacteria from 2012 to 2019 in a tertiary-care teaching hospital in southern China. METHODS: This retrospective study included data from hospital-wide inpatients collected between January 2012 and December 2019. Data on antibacterial consumption were expressed as defined daily doses (DDDs)/1000 patient-days. Antibacterials were classified according to the Anatomical Therapeutic Chemical (ATC) classification system. The trends in antimicrobial usage and resistance were analyzed by linear regression, while Pearson correlation analysis was used for assessing correlations. RESULTS: An increasing trend in the annual consumption of tetracyclines, ß-lactam/ß-lactamase inhibitor (BL/BLI) combinations, and carbapenems was observed (P < 0.05). Carbapenem resistance in Acinetobacter baumannii (A. baumannii) significantly increased (P < 0.05) from 18% in 2012 to 60% in 2019. Moreover, significant positive correlations were found between resistance to carbapenems in A. baumannii (P < 0.05) and Escherichia coli (E. coli; P < 0.05) and consumption of carbapenems, while the resistance rate of A. baumannii to carbapenems was positively correlated with cephalosporin/ß-lactamase inhibitor (C/BLI) combinations (P < 0.01) and tetracyclines usage (P < 0.05). We also found that use of quinolones was positively correlated with the resistance rate of Burkholderia cepacia (B. cepacia) to carbapenems (P < 0.05), and increasing uses of carbapenems (P < 0.01) and penicillin/ß-Lactamase inhibitor (P/BLI) combinations (P < 0.01) were significantly correlated with reduced resistance of Enterobacter cloacae (E. cloacae) to carbapenems. CONCLUSION: These results revealed significant correlations between consumption of antibiotics and carbapenem resistance rates in Gram-negative bacteria. Implementing proper management strategies and reducing the unreasonable use of antibacterial drugs may be an effective measure to reduce the spread of carbapenem-resistant Gram-negative bacteria (CRGN), which should be confirmed by further studies.

Bacterial defenses against a natural antibiotic promote collateral resilience to clinical antibiotics.

Bacterial opportunistic human pathogens frequently exhibit intrinsic antibiotic tolerance and resistance, resulting in infections that can be nearly impossible to eradicate. We asked whether this recalcitrance could be driven by these organisms' evolutionary history as environmental microbes that engage in chemical warfare. Using Pseudomonas aeruginosa as a model, we demonstrate that the self-produced antibiotic pyocyanin (PYO) activates defenses that confer collateral tolerance specifically to structurally similar synthetic clinical antibiotics. Non-PYO-producing opportunistic pathogens, such as members of the Burkholderia cepacia complex, likewise display elevated antibiotic tolerance when cocultured with PYO-producing strains. Furthermore, by widening the population bottleneck that occurs during antibiotic selection and promoting the establishment of a more diverse range of mutant lineages, PYO increases apparent rates of mutation to antibiotic resistance to a degree that can rival clinically relevant hypermutator strains. Together, these results reveal an overlooked mechanism by which opportunistic pathogens that produce natural toxins can dramatically modulate the efficacy of clinical antibiotics and the evolution of antibiotic resistance, both for themselves and other members of clinically relevant polymicrobial communities.

Clinico-microbiological profile of Burkholderia cepacia keratitis: a case series.

BACKGROUND: Burkholderia cepacia, an opportunistic pathogen mainly affecting patients with cystic fibrosis or immunocompromised, has rarely been documented as a cause of corneal infection. The clinical and microbiological profiles of B. cepacia keratitis are reported herein. METHODS: We retrospectively reviewed the medical record of 17 patients with culture-proven B. cepacia keratitis, treated between 2000 and 2019 at Chang Gung Memorial Hospital, Taiwan. Our data included predisposing factors, clinical presentations, treatments, and visual outcomes of B. cepacia keratitis as well as the drug susceptibility of the causative agent. RESULTS: The most common predisposing factor for B. cepacia keratitis was preexisting ocular disease (seven, 41.2%), particularly herpetic keratitis (five). Polymicrobial infection was detected in seven (41.2%) eyes. All B. cepacia isolates were susceptible to ceftazidime. Main medical treatments included levofloxacin or ceftazidime. Surgical treatment was required in five (29.4%) patients. Only four (23.5%) patients exhibited final visual acuity better than 20/200. CONCLUSIONS: B. cepacia keratitis primarily affects patients with preexisting ocular disease, particularly herpetic keratitis, and responds well to ceftazidime or fluoroquinolones. However, the visual outcomes are generally poor.

Outer membrane vesicles produced by Burkholderia cepacia cultured with subinhibitory concentrations of ceftazidime enhance pro-inflammatory responses.

BURKHOLDERIA CEPACIA: is an opportunistic pathogen that infects patients with debilitating underlying diseases. This study investigated the production of outer membrane vesicles (OMVs) by B. cepacia cultured with sub-minimum inhibitory concentrations (MICs) of antibiotics and examined their pathogenic roles both in vitro and in vivo. B. cepacia ATCC 25416 produced more OMVs under antibiotic stress conditions than controls. OMVs isolated from B. cepacia cultured in Luria-Bertani (LB) broth (OMVs/LB) induced cytotoxicity and the expression of pro-inflammatory cytokine genes in A549 cells in a dose-dependent manner. Host cell cytotoxicity and pro-inflammatory responses were significantly higher in A549 cells treated with B. cepacia OMVs cultured with 1/4 MIC of ceftazidime (OMVs/CAZ) than in the cells treated with OMVs/LB, OMVs cultured with 1/4 MIC of trimethoprim/sulfamethoxazole (OMVs/SXT), or OMVs cultured with 1/4 MIC of meropenem. Intratracheal injection of B. cepacia OMVs also induced histopathology in vivo in mouse lungs. Expressions of IL-1ß and TNF-α genes were significantly up-regulatedin the lungs of mice treated with OMVs/CAZ compared to mice administered other OMVs; the expression of the GRO-α gene, however, was significantly up-regulated in OMVs/SXT. In conclusion, OMVs produced by B. cepacia under different antibiotic stress conditions induce different host responses that may contribute to the pathogenesis of B. cepacia.

Comparative efficacy of hospital disinfectants against nosocomial infection pathogens.

BACKGROUND: Due to the increasing rate of hospital-acquired infections, it is essential to select appropriate disinfectant agents. In this study, the efficacy of hospital disinfectants against nosocomial infection pathogens was compared. METHODS: High level disinfectants (Steranios 2%, Deconex HLDPA, and Microzed Quatenol) were tested for their antibacterial effects by determining their minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) against Enterococcus faecalis ATCC 29212 and Burkholderia cepacia ATCC 10673. RESULTS: E. faecalis, as gram-positive bacterium, was more susceptible to high level disinfectants compared to gram-negative B.cepacia. The MIC = MBC values of 2% Steranios, Deconex HLDPA and Microzed Quatenol against E. faecalis and B.cepacia were 0.31, 9.77, 2.2 mg/L and 9.8, 78.13, 70.31 mg/L, respectively. CONCLUSIONS: According to the findings of this study, the most effective disinfectants against both E. faecalis and B.cepacia were Steranios 2%, Microzed Quatenol, and Deconex HLDPA in order. Considering the importance of these bacterial strains in healthcare-associated infections, the use of these effective disinfectants is recommended in the hospitals.

Sulfonamide-based diffusible signal factor analogs interfere with quorum sensing in Stenotrophomonas maltophilia and Burkholderia cepacia.

Aim:Stenotrophomonas maltophilia (Sm) and Burkholderia cepacia complex (BCC) are Gram-negative bacterial pathogens, which are typically multidrug resistant and excellent biofilm producers. These phenotypes are controlled by quorum sensing (QS) systems from the diffusible signal factor (DSF) family. We aim to interfere with this QS system as an alternative approach in combatting such difficult-to-treat infections. Materials & methods: A library of sulfonamide-based DSF bioisosteres was synthesized and tested against the major phenotypes regulated by QS. Results & conclusion: Several analogs display significant antibiofilm activity while the majority increase the action of the last-resort antibiotic colistin against Sm and BCC. Most compounds inhibit DSF synthesis in the Sm K279a strain. Our results support the strategy of interfering with QS communications to combat multidrug resistance.

In Vitro Activity of Cefiderocol, a Siderophore Cephalosporin, Against Gram-Negative Bacilli Isolated by Clinical Laboratories in North America and Europe in 2015-2016: SIDERO-WT-2015.

Cefiderocol (S-649266) is a parenteral siderophore cephalosporin in phase III of clinical development. In this study, we determined the in vitro susceptibility to cefiderocol and comparators of a 2015-2016 collection of 8954 clinical isolates of Gram-negative bacilli (GNB), provided by 100 clinical laboratories in North America and Europe, using the Clinical and Laboratory Standards Institute broth microdilution method. Iron-depleted cation-adjusted Mueller-Hinton broth was used to test cefiderocol. The concentration of cefiderocol inhibiting 90% of isolates (MIC90) was 0.5 mg/L (North America; n=2470) and 1 mg/L (Europe; n=3,543) for Enterobacteriaceae, 0.5 mg/L (North America; n=619) and 0.5 mg/L (Europe; n=921) for Pseudomonas aeruginosa, 1 mg/L (North America; n=308) and 2 mg/L (Europe; n=664) for Acinetobacter spp., 0.5 mg/L (North America; n=165) and 0.25 mg/L (Europe; n=175) for Stenotrophomonas maltophilia, and 0.12 mg/L (North America; n=40) and 0.5 mg/L (Europe; n=49) for Burkholderia cepacia complex spp. Cefiderocol MICs were ≤4 mg/L for 99.9% (6005/6013) of Enterobacteriaceae, 99.9% (1539/1540) of P. aeruginosa, 96.4% (937/972) of Acinetobacter spp., 99.4% (338/340) of S. maltophilia, and 94.4% (84/89) of Burkholderia cepacia complex spp. isolates tested. Against meropenem-non-susceptible isolates, MICs to cefiderocol were ≤4 mg/L for 99.6% (245/246) of Enterobacteriaceae, 99.7% (394/395) of P. aeruginosa, 96.1% (540/562) of Acinetobacter spp., and 87.1% (27/31) of B. cepacia complex spp. We conclude that cefiderocol demonstrated potent in vitro activity (MIC ≤4 mg/L) against the majority (99.4%, 8903/8954) of clinical isolates of GNB in a recent (2015-2016), multi-continent collection, including carbapenem-non-susceptible isolates.

Photodynamic inactivation of Burkholderia cepacia by curcumin in combination with EDTA.

Burkholderia cepacia (B. cepacia) is an aerobic Gram-negative bacillus found in various aquatic environments and can cause food contamination. We investigated the photodynamic antibacterial effects of food additive curcumin combined with EDTA on B. cepacia. We found a ~4-log reduction in B. cepacia viability when photo-irradiated with curcumin at 50 µM by blue LED light (16 mW/cm2) for 30 min with 0.4% (w/v) EDTA. Moreover, the bacterial morphological alterations and the leakage of intracellular contents were observed after photodynamic treatment. There were also obvious genomic DNA cleavage and a general loss of bacterial proteins assigned to large-scale protein degradation after photodynamic inactivation treatment. Collectively, curcumin in combination with EDTA illuminated by blue LED is a potential candidate for photodynamic inactivation of B. cepacia.

Targeting the Nonmevalonate Pathway in Burkholderia cenocepacia Increases Susceptibility to Certain ß-Lactam Antibiotics.

The nonmevalonate pathway is the sole pathway for isoprenoid biosynthesis in Burkholderia cenocepacia and is possibly a novel target for the development of antibacterial chemotherapy. The goals of the present study were to evaluate the essentiality of dxr, the second gene of the nonmevalonate pathway, in B. cenocepacia and to determine whether interfering with the nonmevalonate pathway increases susceptibility toward antibiotics. To this end, a rhamnose-inducible conditional dxr knockdown mutant of B. cenocepacia strain K56-2 (B. cenocepacia K56-2dxr) was constructed, using a plasmid which enables the delivery of a rhamnose-inducible promoter in the chromosome. Expression of dxr is essential for bacterial growth; the growth defect observed in the dxr mutant could be complemented by expressing dxr in trans under the control of a constitutive promoter, but not by providing 2-C-methyl-d-erythritol-4-phosphate, the reaction product of DXR (1-deoxy-d-xylulose 5-phosphate reductoisomerase). B. cenocepacia K56-2dxr showed markedly increased susceptibility to the ß-lactam antibiotics aztreonam, ceftazidime, and cefotaxime, while susceptibility to other antibiotics was not (or was much less) affected; this increased susceptibility could also be complemented by in trans expression of dxr A similarly increased susceptibility was observed when antibiotics were combined with FR900098, a known DXR inhibitor. Our data confirm that the nonmevalonate pathway is essential in B. cenocepacia and suggest that combining potent DXR inhibitors with selected ß-lactam antibiotics is a useful strategy to combat B. cenocepacia infections.

Synergy between Active Efflux and Outer Membrane Diffusion Defines Rules of Antibiotic Permeation into Gram-Negative Bacteria.

Gram-negative bacteria are notoriously resistant to antibiotics, but the extent of the resistance varies broadly between species. We report that in significant human pathogens Acinetobacter baumannii, Pseudomonas aeruginosa, and Burkholderia spp., the differences in antibiotic resistance are largely defined by their penetration into the cell. For all tested antibiotics, the intracellular penetration was determined by a synergistic relationship between active efflux and the permeability barrier. We found that the outer membrane (OM) and efflux pumps select compounds on the basis of distinct properties and together universally protect bacteria from structurally diverse antibiotics. On the basis of their interactions with the permeability barriers, antibiotics can be divided into four clusters that occupy defined physicochemical spaces. Our results suggest that rules of intracellular penetration are intrinsic to these clusters. The identified specificities in the permeability barriers should help in the designing of successful therapeutic strategies against antibiotic-resistant pathogens.IMPORTANCE Multidrug-resistant strains of Gram-negative pathogens rapidly spread in clinics. Significant efforts worldwide are currently directed to finding the rules of permeation of antibiotics across two membrane envelopes of these bacteria. This study created the tools for analysis of and identified the major differences in antibacterial activities that distinguish the permeability barriers of P. aeruginosa, A. baumannii, Burkholderia thailandensis, and B. cepacia We conclude that synergy between active efflux and the outer membrane barrier universally protects Gram-negative bacteria from antibiotics. We also found that the diversity of antibiotics affected by active efflux and outer membrane barriers is broader than previously thought and that antibiotics cluster according to specific biological determinants such as the requirement of specific porins in the OM, targeting of the OM, or specific recognition by efflux pumps. No universal rules of antibiotic permeation into Gram-negative bacteria apparently exist. Our results suggest that antibiotic clusters are defined by specific rules of permeation and that further studies could lead to their discovery.

Neutrophil granule proteins generate bactericidal ammonia chloramine on reaction with hydrogen peroxide.

The neutrophil enzyme, myeloperoxidase, by converting hydrogen peroxide (H2O2) and chloride to hypochlorous acid (HOCl), provides important defense against ingested micro-organisms. However, there is debate about how efficiently HOCl is produced within the phagosome and whether its reactions with phagosomal constituents influence the killing mechanism. The phagosome is a small space surrounding the ingested organism, into which superoxide, H2O2 and high concentrations of proteins from cytoplasmic granules are released. Previous studies imply that HOCl is produced in the phagosome, but a large proportion should react with proteins before reaching the microbe. To mimic these conditions, we subjected neutrophil granule extract to sequential doses of H2O2. Myeloperoxidase in the extract converted all the H2O2 to HOCl, which reacted with the granule proteins. 3-Chlorotyrosine, protein carbonyls and large amounts of chloramines were produced. At higher doses of H2O2, the extract developed potent bactericidal activity against Staphylococcus aureus. This activity was due to ammonia monochloramine, formed as a secondary product from protein chloramines and dichloramines. Isolated myeloperoxidase and elastase also became bactericidal when modified with HOCl and antibacterial activity was seen with a range of species. Comparison of levels of protein modification in the extract and in phagosomes implies that a relatively low proportion of phagosomal H2O2 would be converted to HOCl, but there should be sufficient for substantial protein chloramine formation and some breakdown to ammonia monochloramine. It is possible that HOCl could kill ingested bacteria by an indirect mechanism involving protein oxidation and monochloramine formation.

Report - Prevalence of hospital acquired Burkholderia cepacia infection and its antimicrobial susceptibility in a Chinese hospital.

This study aimed to investigate antimicrobial susceptibility of hospital acquired Burkholderia cepacia infection in Shanxi (China) during August 2009 and December 2012. To characterize an emerging nocosomial infection. The medical records of 112 patients that were tested positive for B. cepacia were retrospectively analyzed. The K-B disk diffusion method was used to determine the drug susceptibility of the isolated strains. A hundred and fifty strains of B. cepacia were isolated from 112 patients. The sensitivity rates of B. cepacia to meropenem, imipenem, cotrimoxazole, minocycline and ceftazidime were 65.7%, 14.3%, 76.0%, 68.1% and 74.1%, respectively. All patients suffered from more than two underlying diseases, 89 (79.5%) from another bacterial infection and 92 (82.1%) with indwelling catheter. All patients were given antibiotics, including 62 patients that received carbapenem antibiotics. The average duration of hospitalization before detection of B. cepacia was 31±24 days, after which 65 patients (58.0%) improved, 22 (19.0%) died, 8 (7.1%) quit the therapy, and 17 (15.2%) were discharged after full recovery. The prevalence of hospital acquired B. cepacia infection and drug-resistance in the hospital is reported and risk factor exploration requires further study.

Prevalence of Burkholderia species, including members of Burkholderia cepacia complex, among UK cystic and non-cystic fibrosis patients.

PURPOSE: We aimed to establish the prevalence of different Burkholderia species among UK cystic fibrosis (CF) and non-CF patients over a 2 year period. METHODOLOGY: Matrix-assisted laser desorption/ionization-time of flight mass spectrometry was used to identify isolates to genus level, followed by recA/gyrB sequence clustering or species-specific PCR. In all, 1047 Burkholderia isolates were submitted for identification from 361 CF patients and 112 non-CF patients, 25 from the hospital environment and three from a commercial company. Potential cross-infection was assessed by pulsed-field gel electrophoresis (PFGE) and multi- locus-sequence typing (MLST). MICs were determined for 161 Burkholderia cepacia complex (Bcc) isolates. CF Trust registry data were sought to examine clinical parameters relating to Bcc infection. RESULTS: Burkholderia multivorans was the most prevalent species among CF patients affecting 56 % (192) patients, followed by Burkholderia cenocepacia IIIA (15 %; 52 patients). Five novel recA clusters were found. Among non-CF patients, Burkholderia cepacia was the most prevalent species (37/112; 34 %), with 18 of 40 isolates part of a UK-wide B. cepacia 'cluster'. This and three other clusters were investigated by PFGE and MLST. Cable-pili positive isolates included two novel sequence types and representatives of ET12. Antibiotic susceptibility varied between and within species and CF/non- CF isolates. CF Trust registry data suggested no significant difference in lung function between patients harbouring B. cenocepacia, B. multivorans and other Bcc species (P=0.81). CONCLUSION: The dominance of B. multivorans in CF, the presence of a B. cepacia cluster among non-CF patients and the existence of putative novel species all highlighted the continuing role of Burkholderia species as opportunistic pathogens.

Survival after lung transplantation for cystic fibrosis in Sweden.

Objectives: In Sweden, lung transplantation has been performed in patients with end-stage lung disease since 1990. We assessed survival after lung transplantation for cystic fibrosis (CF) with focus on early mortality and outcome for patients infected with certain multiresistant bacteria, considered a relative contraindication for lung transplantation. Methods: Review of CF and transplant databases and patient charts. The Kaplan-Meier method and log-rank test were used for survival analysis and group comparison. Results: From November 1991 to December 2014, 115 transplantations were performed in 106 CF patients (9 retransplantations): 3 heart-lung, 106 double lung-, 1 double lobar- and 5 single lung transplantations, constituting 13% (115/909) of all lung-transplant procedures performed in Sweden. The mean age at surgery was 31 (SD 10, range 10-61) years and there were 48% females. Overall 1-year survival after lung transplantation for CF was 86.4%, 5-year survival was 73.7% and 10-year survival was 62.4%. The mean and median survival after transplantation were 13.1 (95% confidence interval (CI): 11-15.3) and 14.6 (95% CI: 9.3-19.8) years, respectively, and there was no significant difference for gender or transplant centre. Extracorporeal membrane oxygenation was used as a bridge to transplantation in 11 cases and five patients received reconditioned lungs. Vascular and infectious complications contributed to eight deaths within the first three postoperative months. The mean survival for 14 patients infected pretransplant with Mycobacterium abscessus or Burkholderia cepacia complex was 8.8 (95% CI: 6.1-11.6) years compared to 13.2 (95% CI: 10.9-15.8) years for patients negative for these bacteria. Nineteen patients (14% of all listed), of whom three were listed for retransplantation, died while waiting a median time of 94 days (range 4 days-2.5 years) after listing. Conclusions: Survival after lung transplantation in Sweden is good, also for patients with pretransplant infection with M. abscessus or B. cepacia complex, and comparable to international data.

Influence of triethyl phosphate on phosphatase activity in shooting range soil: Isolation of a zinc-resistant bacterium with an acid phosphatase.

Phosphatase-mediated hydrolysis of organic phosphate may be a viable means of stabilizing heavy metals via precipitation as a metal phosphate in bioremediation applications. We investigated the effect of triethyl phosphate (TEP) on soil microbial-phosphatase activity in a heavy-metal contaminated soil. Gaseous TEP has been used at subsurface sites for bioremediation of organic contaminants but not applied in heavy-metal contaminated areas. Little is known about how TEP affects microbial activity in soils and it is postulated that TEP can serve as a phosphate source in nutrient-poor groundwater and soil/sediments. Over a 3-week period, TEP amendment to microcosms containing heavy-metal contaminated soil resulted in increased activity of soil acid-phosphatase and repression of alkaline phosphatase, indicating a stimulatory effect on the microbial population. A soil-free enrichment of microorganisms adapted to heavy-metal and acidic conditions was derived from the TEP-amended soil microcosms using TEP as the sole phosphate source and the selected microbial consortium maintained a high acid-phosphatase activity with repression of alkaline phosphatase. Addition of 5mM zinc to soil-free microcosms had little effect on acid phosphatase but inhibited alkaline phosphatase. One bacterial member from the consortium, identified as Burkholderia cepacia sp., expressed an acid-phosphatase activity uninhibited by high concentrations of zinc and produced a soluble, indigo pigment under phosphate limitation. The pigment was produced in a phosphate-free medium and was not produced in the presence of TEP or phosphate ion, indicative of purple acid-phosphatase types that are pressed by bioavailable phosphate. These results demonstrate that TEP amendment was bioavailable and increased overall phosphatase activity in both soil and soil-free microcosms supporting the possibility of positive outcomes in bioremediation applications.

Protein-protein interaction and molecular dynamics analysis for identification of novel inhibitors in Burkholderia cepacia GG4.

The lack of complete treatments and appearance of multiple drug-resistance strains of Burkholderia cepacia complex (Bcc) are causing an increased risk of lung infections in cystic fibrosis patients. Bcc infection is a big risk to human health and demands an urgent need to identify new therapeutics against these bacteria. Network biology has emerged as one of the prospective hope in identifying novel drug targets and hits. We have applied protein-protein interaction methodology to identify new drug-target candidates (orthologs) in Burkhloderia cepacia GG4, which is an important strain for studying the quorum-sensing phenomena. An evolutionary based ortholog mapping approach has been applied for generating the large scale protein-protein interactions in B. Cepacia. As a case study, one of the identified drug targets; GEM_3202, a NH (3)-dependent NAD synthetase protein has been studied and the potential ligand molecules were screened using the ZINC database. The three dimensional structure (NH (3)-dependent NAD synthetase protein) has been predicted from MODELLERv9.11 tool using multiple PDB templates such as 3DPI, 2PZ8 and 1NSY with sequence identity of 76%, 50% and 50% respectively. The structure has been validated with Ramachandaran plot having 100% residues of NadE in allowed region and overall quality factor of 81.75 using ERRAT tool. High throughput screening and Vina resulted in two potential hits against NadE such as ZINC83103551 and ZINC38008121. These molecules showed lowest binding energy of -5.7kcalmol-1 and high stability in the binding pockets during molecular dynamics simulation analysis. The similar approach for target identification could be applied for clinical strains of other pathogenic microbes.