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.

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.

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.

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.

Burkholderia Sepsis in Children as a Hospital-Acquired Infection.

PURPOSE: Hospital-acquired Burkholderia cepacia (B. cepacia) infection are not commonly recorded in patients without underlying lung disease, such as cystic fibrosis and chronic granulomatous disease. However, in 2014, B. cepacia appeared more frequently in pediatric blood samples than in any other year. In order to access this situation, we analyzed the clinical characteristics of B. cepacia infections in pediatric patients at our hospital. MATERIALS AND METHODS: We conducted a retrospective study of blood isolates of B. cepacia taken at our hospital between January 2004 and December 2014. Patient clinical data were obtained by retrospective review of electronic medical records. We constructed a dendrogram for B. cepacia isolates from two children and five adult patients. RESULTS: A total of 14 pediatric patients and 69 adult patients were identified as having B. cepacia bacteremia. In 2014, higher rates of B. cepacia bacteremia were observed in children. Most of them required Intensive Care Unit (ICU) care (12/14). In eleven children, sputum cultures were examined, and five of these children had the same strain of B. cepacia that grew out from their blood samples. Antibiotics were administered based on antibiotic sensitivity results. Four children expired despite treatment. Compared to children, there were no demonstrative differences in adults, except for history of ICU care. CONCLUSION: Although there were not many pediatric cases at our hospital, awareness of colonization through hospital-acquired infection and effective therapy for infection of B. cepacia is needed, as it can cause mortality and morbidity.

Investigating the Role of the Host Multidrug Resistance Associated Protein Transporter Family in Burkholderia cepacia Complex Pathogenicity Using a Caenorhabditis elegans Infection Model.

This study investigated the relationship between host efflux system of the non-vertebrate nematode Caenorhabditis elegans and Burkholderia cepacia complex (Bcc) strain virulence. This is the first comprehensive effort to profile host-transporters within the context of Bcc infection. With this aim, two different toxicity tests were performed: a slow killing assay that monitors mortality of the host by intestinal colonization and a fast killing assay that assesses production of toxins. A Virulence Ranking scheme was defined, that expressed the toxicity of the Bcc panel members, based on the percentage of surviving worms. According to this ranking the 18 Bcc strains were divided in 4 distinct groups. Only the Cystic Fibrosis isolated strains possessed profound nematode killing ability to accumulate in worms' intestines. For the transporter analysis a complete set of isogenic nematode single Multidrug Resistance associated Protein (MRP) efflux mutants and a number of efflux inhibitors were interrogated in the host toxicity assays. The Bcc pathogenicity profile of the 7 isogenic C. elegans MRP knock-out strains functionality was classified in two distinct groups. Disabling host transporters enhanced nematode mortality more than 50% in 5 out of 7 mutants when compared to wild type. In particular mrp-2 was the most susceptible phenotype with increased mortality for 13 out 18 Bcc strains, whereas mrp-3 and mrp-4 knock-outs had lower mortality rates, suggesting a different role in toxin-substrate recognition. The use of MRP efflux inhibitors in the assays resulted in substantially increased (>40% on average) mortality of wild-type worms.

Application of ethylene diamine tetra acetic acid degrading bacterium Burkholderia cepacia on biotreatment process.

Ethylene diamine tetra acetic acid (EDTA), the effluent of secondary biotreatment units, can be properly biodegraded by Burkholderia cepacia. Through batch degradation of EDTA, the raw wastewater of EDTA was controlled at 50 mg/L, and then nutrients was added in diluted wastewater to cultivate activated sludge, which the ratio of composition is depicted as "COD:N:P:Fe = 100:5:1:0.5". After 27 days, the removal efficiency of Fe-EDTA and COD was 100% and 92.0%, correspondingly. At the continuous process, the raw wastewater of EDTA was dictated at 166 mg/L before adding nutrients to cultivate activated sludge, in which the ratio of composition did also follow with batch process. After 22 days, the removal efficiency of Fe-EDTA and COD for experimental group was 71.46% and 62.58%, correspondingly. The results showed that the batch process was more suited for EDTA biodegradation.

Microorganismos involucrados en las infecciones respiratorias de pacientes con fibrosis quísitca / Microorganisms involved in respiratory infections in cystic fibrosis patients

La fibrosis quística es la enfermedad autosómica recesiva letal más frecuente en la infancia. Se caracteriza por presentar una evolución crónica, progresiva y compromiso multisistémico. El objetivo de este trabajo fue conocer la frecuencia de los microorganismos implicados en las infecciones respiratorias de pacientes fibroquísticos atendidos en el Hospital de Pediatría Prof. Dr. Juan P. Garrahan durante el año 2012 y su resistencia a los antimicrobianos. Para la identificación bacteriana se utilizaron pruebas bioquímicas convencionales, sistemas automatizados y semiautomatizados. En la identificación de miembros del complejo Burkholderia cepacia se utilizaron además métodos moleculares. De esta manera se pudo lograr la clasificación genética de las especies incluidas dentro de ese complejo presentes en los pacientes fibroquísticos de nuestro medio. Este trabajo nos permitió conocer la situación microbiológica actual de las infecciones respiratorias en los pacientes fibroquísticos. Tanto el estudio minucioso de los cultivos convencionales como la caracterización molecular de las especies de B. cepacia deben seguirse en los pacientes colonizados por microorganismos multirresistentes y son imprescindibles en el control postratamiento después del aislamiento de estos patógenos (AU)

Cystic fibrosis is the most common lethal autosomal recessive disease in childhood. It is characterized by a chronic, progressive evolution and multisystemic involvement. The aim of this study was to assess the incidence of the microorganisms involved in respiratory infections of patients with cystic fibrosis seen at the Pediatric Hospital Prof. Dr. Juan P. Garrahan in 2012 and their resistance to antimicrobial agents. To identify the microorganisms conventional biochemical tests with automatized and semiautomatized systems were used. For the identification of members of the Burkholderia cepacia complex molecular studies were additionally used. Species of this complex found in cystic fibrosis patients in our setting were genetically classified allowing for the definition of the current microbiological situation of respiratory infections in cystic fibrosis patients. Careful study of conventional cultures as well as molecular typing of the B. cepacia species should be routinely performed in patients colonized by multiresistant microorganisms and is fundamental in the post-treatment monitoring after the isolation of these pathogens (AU)

Investigating the role of matrix components in protection of Burkholderia cepacia complex biofilms against tobramycin.

BACKGROUND: Burkholderia cepacia complex (Bcc) organisms produce a wide variety of potential virulence factors, including exopolysaccharides (EPS), and exhibit intrinsic resistance towards many antibiotics. In the present study we investigated the contribution of Bcc biofilm matrix components, including extracellular DNA, cepacian and poly-ß-1,6-N-acetylglucosamine, to tobramycin susceptibility. METHODS: The in vitro bactericidal activity of tobramycin in combination with recombinant human DNase (rhDNase), NaClO and dispersin B was tested against Bcc biofilms. RESULTS: EPS degradation by NaClO pretreatment and specific PNAG degradation by dispersin B significantly increased the bactericidal effect of tobramycin towards some of the Bcc biofilms tested, including the strains of Burkholderia cenocepacia, B. cepacia and Burkholderia metallica. The presence of rhDNase during biofilm treatment and/or development had no influence on tobramycin activity. CONCLUSION: These results suggest that EPS play a role in tobramycin susceptibility of Bcc biofilms and that matrix degrading combination therapy could improve treatment of Bcc biofilm infections.

Biodiesel production from Jatropha oil catalyzed by immobilized Burkholderia cepacia lipase on modified attapulgite.

Lipase from Burkholderia cepacia was immobilized on modified attapulgite by cross-linking reaction for biodiesel production with jatropha oil as feedstock. Effects of various factors on biodiesel production were studied by single-factor experiment. Results indicated that the best conditions for biodiesel preparation were: 10 g jatropha oil, 2.4 g methanol (molar ratio of oil to methanol is 1:6.6) being added at 3h intervals, 7 wt% water, 10 wt% immobilized lipase, temperature 35°C, and time 24h. Under these conditions, the maximum biodiesel yield reached 94%. The immobilized lipase retained 95% of its relative activity during the ten repeated batch reactions. The half-life time of the immobilized lipase is 731 h. Kinetics was studied and the Vmax of the immobilized lipases were 6.823 mmol L(-1). This immobilized lipase catalyzed process has potential industrial use for biodiesel production to replace chemical-catalyzed method.

Microcalorimetric investigation of the effect of non-ionic surfactant on biodegradation of pyrene by PAH-degrading bacteria Burkholderia cepacia.

Polycyclic aromatic hydrocarbons (PAHs) are widespread in various ecosystems and are pollutants of great concern due to their potential toxicity, mutagenecity and carcinogenicity. Surfactant has become a hot topic for its wide application in the bioremediation of PAHs. The aim of this work is to explore a microcalorimetric method to determine the toxic effect of pyrene on Bacillus subtilis (B. subtilis) and the PAH-degrading bacteria Burkholderia cepacia (B. cepacia) and to evaluate the effect of Tween 80 on biodegradation of pyrene. Power-time curves were studied and calorimetric parameters including the growth rate constant (k), half inhibitory concentration (IC50), and total thermal effect (Q(T)) were determined. B. subtilis, B. cepacia and B. cepacia with Tween 80 were completely inhibited when the concentration of pyrene were 200, 800 and 1600 µg mL⁻¹, respectively. B. cepacia shows better tolerance to pyrene than B. subtilis. Tween 80 significantly improves the biodegradation of pyrene by increasing the bioavailability of pyrene. In addition, the expression of catechol 2,3-dioxygenase (C23O) in B. cepacia is responsible for the degradation of pyrene and plays an important role in improving the biodegradation of pyrene. Moreover, the activity of C23O increases with the application of Tween 80. The enhanced bioavailability and biodegradation of pyrene by Tween 80 shows the potential use of Tween 80 in the PAHs bioremediation.

Biodegradation of petroleum hydrocarbons in the presence of nickel and cobalt.

Bioremediation of environments co-contaminated with hydrocarbons and heavy metals often pose a challenge as heavy metals exert toxicity to existing communities of hydrocarbon degraders. Multi-resistant bacterial strains were studied for ability to degrade hydrocarbons in chemically defined media amended with 5.0 mM Ni(2+), and Co(2+). The bacteria, Pseudomonas aeruginosa CA207Ni, Burkholderia cepacia AL96Co, and Corynebacterium kutscheri FL108Hg, utilized crude oil and anthracene without lag phase at specific growth rate spanning 0.3848-0.8259 per day. The bacterial populations grew in hydrocarbon media amended with nickel (Ni) and cobalt (Co) at 0.8393-1.801 days generation time (period of exponential growth, t = 15 days). The bacteria degraded 96.24-98.97, and 92.94-96.24% of crude oil, and anthracene, respectively, within 30 days without any impedance due to metal toxicity (at 5.0 mM). Rather, there was reduction of Ni and Co concentrations in the axenic culture 30 days post-inoculation to 0.08-0.12 and 0.11-0.15 mM, respectively. The metabolic functions of the bacteria are active in the presence of toxic metals (Ni and Co) while utilizing petroleum hydrocarbons for increase in biomass. These findings are useful to other baseline studies on decommissioning of sites co-contaminated with hydrocarbons and toxic metals.

Cellulase inhibits Burkholderia cepacia biofilms on diverse prosthetic materials.

Burkholderia cepacia is an opportunistic pathogen causing infections in patients with cystic fibrosis. Patients with implanted devices are prone to B. cepacia infections due to its ability to grow as biofilms. Knowing the importance of polysaccharides in a biofilm, enzymes that degrade them were targeted as a possible candidate for antibiofilm agents. In this study, the antibiofilm potential of cellulase against B. cepacia biofilms formed on various prosthetic materials was tested. Cellulase exhibited significant antibiofilm activity against B. cepacia without having much action on its growth, thus ruling out the chance of selection pressure and subsequent development resistance.

Proteomic tracking and analysis of a bacterial mixed culture.

To improve the understanding of microbial behaviors in communities, proteomic tracking, an approach for relative quantification of species-specific population dynamics of mixed cultures, was developed. Therefore, a bacterial mixed culture was analyzed during batch cultivations with and without addition of the antibiotic Ceftazidime. The community was composed of Burkholderia cepacia, Pseudomonas aeruginosa, and Staphylococcus aureus, pathogens causing infections in cystic fibrosis patients. Gel-based proteomics and mass spectrometry were used to obtain qualitative and quantitative proteomic data. During cultivation, P. aeruginosa became dominant within the mixed culture while S. aureus was inhibited in growth. Analysis of samples - taken along cultivation - revealed about 270 differentially expressed proteins. Some of those proteins are related to bacterial interactions, response to antibiotic treatment or metabolic shifts. For instance, the enzymes PhzS(flavin-containing monooxygenase), PhzD (phenazine biosynthesis protein), and PhzG2 (pyridoxamine 5'-phosphate oxidase) indicated the production of the antibiotic pigment pyocyanine by P. aeruginosa that is related to oxidative stress and therefore, might inhibit growth of S. aureus. Overall, the strategy applied not only allows species-specific tracking of the community composition but also provides valuable insights into the behavior of mixed cultures.

A rare case of community acquired Burkholderia cepacia infection presenting as pyopneumothorax in an immunocompetent individual.

Burkholderia cepacia (B. cepacia) infection is rarely reported in an immunocompetent host. It is a well known occurence in patients with cystic fibrosis and chronic granulomatous disease where it increases both morbidity and mortality. It has also been included in the list of organisms causing nosocomial infections in an immunocompetent host, most of them transmitted from the immunocompromised patient in which this organism harbors. We report a rare case of isolation of B. cepacia from the bronchoalveolar lavage fluid of an immunocompetent agriculturist who presented with productive cough and fever associated with a pyopneumothorax. This is the first case of community acquired infection reported in an immunocompetent person in India.

Extractive fermentation for improved production and recovery of lipase derived from Burkholderia cepacia using a thermoseparating polymer in aqueous two-phase systems.

An extractive fermentation technique was developed using a thermoseparating reagent to form a two-phase system for simultaneous cell cultivation and downstream processing of extracellular Burkholderia cepacia lipase. A 10% (w/w) solution of ethylene oxide-propylene oxide (EOPO) with a molecular mass of 3900 g/mol and pH 8.5, a 200 rpm speed, and 30 °C were selected as the optimal conditions for lipase production (55 U/ml). Repetitive batch fermentation was performed by continuous replacement of the top phase every 24h, which resulted in an average cell growth mass of 4.7 g/L for 10 extractive batches over 240 h. In scaling-up the process, a bench-scale bioreactor was tested under the conditions that had been optimized in flasks. The production rate and recovery yield were higher in the bioreactor compared to fermentation performed in flasks.

[Burkholderia cepacia bacteremia: a prospective analysis of 33 episodes]. / Bacteriemias por Burkholderia cepacia: análisis prospectivo de 33 episodios.

INTRODUCTION: The aim of this study is to describe clinical characteristics and outcome of Burkholderia cepacia bacteraemia, susceptibility of the isolates and differences between cases from epidemic outbreaks and sporadic cases. MATERIAL AND METHODS: From 1993 to 2009, episodes of B. cepacia bacteraemia were prospectively collected in a university hospital. RESULTS: A total of 33 episodes were included, of which 21 were part of two outbreaks (9 in 1994 and 12 in 2006). Outbreak cases had a median age of 58 years, 45% had neoplasia, median length of stay until bacteraemia was 15 d (range 0-120) and 82% had received an antibiotic. The most prevalent sources of bacteraemia were catheter (48%) and unknown (33%). On the other hand, sporadic cases stayed longer until diagnosis (median 25 days versus 11, p=0.041) and showed a trend to have neoplasia more frequently (83% versus 33%, p=0.083). Susceptibility to antibiotics was varied and co-trimoxazole was the only active agent against all strains. CONCLUSIONS: B. cepacia is an uncommon pathogen, which affects patients with prolonged hospitalization and severe comorbidities. The identification of more than one case in a short term of time should raise the suspicion of an outbreak.

Clinical characteristics and outcomes of patients with Burkholderia cepacia bacteremia in an intensive care unit.

The purpose of this study was to investigate a cohort of patients with Burkholderia cepacia bacteremia in the intensive care unit (ICU) at our institution. A large outbreak of B. cepacia bacteremia involving 95 patients lasted for 4 years in an ICU in northern Taiwan. The clinical characteristics and antimicrobial treatment responses of these patients were analyzed. Minimal inhibitory concentrations were determined and pulse-field gel electrophoresis was performed for the 73 available isolates. Overall, the in-hospital mortality rate was 53.8% and the 14-day mortality rate was 16.8%. Most patients (95.6%) had several underlying diseases and all but 1 patient had tracheal intubation. Malignancy (37.5% versus 13.9%, P = 0.02) and higher Sequential Organ Failure Assessment (SOFA) scores at the onset of bacteremia (11.9 ± 4.7 versus 7.9 ± 3.6, P < 0.001) were significant risk factors for 14-day mortality. In contrast, treatment with ceftazidime (76.0% versus 43.7%, P = 0.02) and diabetes (51.9% versus 13.8%, P = 0.01) were associated with decreased mortality. In the multivariate analysis, malignancy and higher SOFA score were significant risk factors for mortality [odds ratio (OR) 12.45, 95% confidence interval (CI) 2.35-65.94; OR 1.20, 95% CI 1.00-1.45, respectively]. Meropenem, ceftazidime, and piperacillin-tazobactam were the most active agents (susceptible rate 100%, 97.3%, and 97.3%, respectively). Pulsed-field gel electrophoresis results indicated 49 of the 73 isolates could be classified as outbreak-related strains. There was no significant difference in the clinical characteristics and outcomes of patients with bacteremia due to outbreak-related and non-outbreak-related strains. In conclusion, malignancy and a higher SOFA score at onset of bacteremia predicted increased mortality, but the clinical presentation and outcome of patients with outbreak and non-outbreak strains were similar.