Non-coding regulatory sRNAs from bacteria of the Burkholderia cepacia complex.

Small non-coding RNAs (sRNAs) are key regulators of post-transcriptional gene expression in bacteria. Hundreds of sRNAs have been found using in silico genome analysis and experimentally based approaches in bacteria of the Burkholderia cepacia complex (Bcc). However, and despite the hundreds of sRNAs identified so far, the number of functionally characterized sRNAs from these bacteria remains very limited. In this mini-review, we describe the general characteristics of sRNAs and the main mechanisms involved in their action as regulators of post-transcriptional gene expression, as well as the work done so far in the identification and characterization of sRNAs from Bcc. The number of functionally characterized sRNAs from Bcc is expected to increase and to add new knowledge on the biology of these bacteria, leading to novel therapeutic approaches to tackle the infections caused by these opportunistic pathogens, particularly severe among cystic fibrosis patients. KEY POINTS: •Hundreds of sRNAs have been identified in Burkholderia cepacia complex bacteria (Bcc). •A few sRNAs have been functionally characterized in Bcc. •Functionally characterized Bcc sRNAs play major roles in metabolism, biofilm formation, and virulence.

Surface-Exposed Protein Moieties of Burkholderia cenocepacia J2315 in Microaerophilic and Aerobic Conditions.

Burkholderia cepacia complex infections remain life-threatening to cystic fibrosis patients, and due to the limited eradication efficiency of current treatments, novel antimicrobial therapies are urgently needed. Surface proteins are among the best targets to develop new therapeutic strategies since they are exposed to the host's immune system. A surface-shaving approach was performed using Burkholderia cenocepacia J2315 to quantitatively compare the relative abundance of surface-exposed proteins (SEPs) expressed by the bacterium when grown under aerobic and microaerophilic conditions. After trypsin incubation of live bacteria and identification of resulting peptides by liquid chromatography coupled with mass spectrometry, a total of 461 proteins with ≥2 unique peptides were identified. Bioinformatics analyses revealed a total of 53 proteins predicted as localized at the outer membrane (OM) or extracellularly (E). Additionally, 37 proteins were predicted as moonlight proteins with OM or E secondary localization. B-cell linear epitope bioinformatics analysis of the proteins predicted to be OM and E-localized revealed 71 SEP moieties with predicted immunogenic epitopes. The protegenicity higher scores of proteins BCAM2761, BCAS0104, BCAL0151, and BCAL0849 point out these proteins as the best antigens for vaccine development. Additionally, 10 of the OM proteins also presented a high probability of playing important roles in adhesion to host cells, making them potential targets for passive immunotherapeutic approaches. The immunoreactivity of three of the OM proteins identified was experimentally demonstrated using serum samples from cystic fibrosis patients, validating our strategy for identifying immunoreactive moieties from surface-exposed proteins of potential interest for future immunotherapies development.

A Polyclonal Antibody against a Burkholderia cenocepacia OmpA-like Protein Strongly Impairs Pseudomonas aeruginosa and B. multivorans Virulence.

Despite advances in therapies, bacterial chronic respiratory infections persist as life-threatening to patients suffering from cystic fibrosis (CF). Pseudomonas aeruginosa and bacteria of the Burkholderia cepacia complex are among the most difficult of these infections to treat, due to factors like their resistance to multiple antibiotics and ability to form biofilms. The lack of effective antimicrobial strategies prompted our search for alternative immunotherapies that can effectively control and reduce those infections among CF patients. Previous work from our group showed that the anti-BCAL2645 goat polyclonal antibody strongly inhibited Burkholderia cenocepacia to adhere and invade cultured epithelial cells. In this work, we showed that the polyclonal antibody anti-BCAL2645 also strongly inhibited the ability of P. aeruginosa to form biofilms, and to adhere and invade the human bronchial epithelial cell line CFBE41o-. The polyclonal antibody also inhibited, to a lesser extent, the ability of B. multivorans to adhere and invade the human bronchial epithelial cell line CFBE41o. We also show that the ability of B. cenocepacia, P. aeruginosa and B. multivorans to kill larvae of the Galleria mellonella model of infection was impaired when bacteria were incubated with the anti-BCAL2645 antibody prior to the infection. Our findings show that an antibody against BCAL2645 possesses a significant potential for the development of new immunotherapies against these three important bacterial species capable of causing devastating and often lethal infections among CF patients.

Advances in Human Pathogen Control-A 21st Century Challenge.

The emergence of new pathogens, coupled with the reemergence of old pathogens and the steep worldwide increase in multiple resistances to available antimicrobials, poses major challenges to human health at the global scale [...].

Identification of Burkholderia cenocepacia non-coding RNAs expressed during Caenorhabditis elegans infection.

Small non-coding RNAs (sRNAs) are key regulators of post-transcriptional gene expression in bacteria. Despite the identification of hundreds of bacterial sRNAs, their roles on bacterial physiology and virulence remain largely unknown, as is the case of bacteria of the Burkholderia cepacia complex (Bcc). Bcc is a group of opportunistic pathogens with relatively large genomes that can cause lethal lung infections amongst cystic fibrosis (CF) patients. To characterise sRNAs expressed by Bcc bacteria when infecting a host, the nematode Caenorhabditis elegans was used as an infection model by the epidemic CF strain B. cenocepacia J2315. A total of 108 new and 31 previously described sRNAs with a predicted Rho independent terminator were identified, most of them located on chromosome 1. RIT11b, a sRNA downregulated under C. elegans infection conditions, was shown to directly affect B. cenocepacia virulence, biofilm formation, and swimming motility. RIT11b overexpression reduced the expression of the direct targets dusA and pyrC, involved in biofilm formation, epithelial cell adherence, and chronic infections in other organisms. The in vitro direct interaction of RIT11b with the dusA and pyrC messengers was demonstrated by electrophoretic mobility shift assays. To the best of our knowledge this is the first report on the functional characterization of a sRNA directly involved in B. cenocepacia virulence. KEY POINTS: • 139 sRNAs expressed by B. cenocepacia during C. elegans infection were identified • The sRNA RIT11b affects B. cenocepacia virulence, biofilm formation, and motility • RIT11b directly binds to and regulates dusA and pyrC mRNAs.

Antitumoral and Antimicrobial Activities of Block Copolymer Micelles Containing Gold Bisdithiolate Complexes.

Gold(III) bisdithiolate complexes have been reported as potential antimicrobial and antitumoral agents. The complex [Au(cdc)2]- (cdc=cyanodithioimido carbonate) displayed antimicrobial and outstanding antitumor activity against the ovarian cancer cells A2780 and A2780cisR, which are sensitive and resistant to cisplatin, respectively. However, poor water solubility may hamper its clinical use. Block copolymer micelles (BCMs) may solubilize hydrophobic drugs, improving their bioavailability and circulation time in blood. Aiming to provide water solubility, prolonged availability, and enhanced therapeutic indexes, BCMs loaded with [Au(cdc)2]- were synthesized and characterized. The BCM-[Au(cdc)2] micelles were prepared with a loading efficiency of 64.6% and a loading content of 35.3 mg [Au(cdc)2]-/gBCM. A hydrodynamic diameter of 77.31 ± 27.00 nm and a low polydispersity index of 0.18 indicated that the micelles were homogenous and good candidates for drug delivery. Cytotoxic activity studies against A2780/A2780cisR cells showed that BCM-[Au(cdc)2] maintained relevant cytotoxic activity comparable to the cytotoxicity observed for the same concentration of gold complexes. The Au uptake in A2780 cells, determined by PIXE, was ca. 17% higher for BCMs-[Au(cdc)2] compared to [Au(cdc)2]-. The BCMs-[Au(cdc)2] presented antimicrobial activity against S. aureus Newman and C. glabrata CBS138. These results evidenced the potential of BCM-[Au(cdc)2] for drug delivery and its promising anticancer and antimicrobial activities.

Comparison of Virulence-Factor-Encoding Genes and Genotype Distribution amongst Clinical Pseudomonas aeruginosa Strains.

Pseudomonas aeruginosa is an opportunistic pathogen encoding several virulence factors in its genome, which is well-known for its ability to cause severe and life-threatening infections, particularly among cystic fibrosis patients. The organism is also a major cause of nosocomial infections, mainly affecting patients with immune deficiencies and burn wounds, ventilator-assisted patients, and patients affected by other malignancies. The extensively reported emergence of multidrug-resistant (MDR) P. aeruginosa strains poses additional challenges to the management of infections. The aim of this study was to compare the incidence rates of selected virulence-factor-encoding genes and the genotype distribution amongst clinical multidrug-sensitive (MDS) and MDR P. aeruginosa strains. The study involved 74 MDS and 57 MDR P. aeruginosa strains and the following virulence-factor-encoding genes: lasB, plC H, plC N, exoU, nan1, pilA, and pilB. The genotype distribution, with respect to the antimicrobial susceptibility profiles of the strains, was also analyzed. The lasB and plC N genes were present amongst several P. aeruginosa strains, including all the MDR P. aeruginosa, suggesting that their presence might be used as a marker for diagnostic purposes. A wide variety of genotype distributions were observed among the investigated isolates, with the MDS and MDR strains exhibiting, respectively, 18 and 9 distinct profiles. A higher prevalence of genes determining the virulence factors in the MDR strains was observed in this study, but more research is needed on the prevalence and expression levels of these genes in additional MDR strains.

Microbial Antigen Identification and Vaccine Delivery Systems.

Vaccine efficacy and immunogenicity depend on the host, pathogen, and pathogenesis of the disease [...].

Antibody-Based Immunotherapies as a Tool for Tackling Multidrug-Resistant Bacterial Infections.

The discovery of antimicrobials is an outstanding achievement of mankind that led to the development of modern medicine. However, increasing antimicrobial resistance observed worldwide is rendering commercially available antimicrobials ineffective. This problem results from the bacterial ability to adapt to selective pressure, leading to the development or acquisition of multiple types of resistance mechanisms that can severely affect the efficacy of antimicrobials. The misuse, over-prescription, and poor treatment adherence by patients are factors strongly aggravating this issue, with an epidemic of infections untreatable by first-line therapies occurring over decades. Alternatives are required to tackle this problem, and immunotherapies are emerging as pathogen-specific and nonresistance-generating alternatives to antimicrobials. In this work, four types of antibody formats and their potential for the development of antibody-based immunotherapies against bacteria are discussed. These antibody isotypes include conventional mammalian polyclonal antibodies that are used for the neutralization of toxins; conventional mammalian monoclonal antibodies that currently have 100 IgG mAbs approved for therapeutic use; immunoglobulin Y found in birds and an excellent source of high-quality polyclonal antibodies able to be purified noninvasively from egg yolks; and single domain antibodies (also known as nanobodies), a recently discovered antibody format (found in camelids and nurse sharks) that allows for a low-cost synthesis in microbial systems, access to hidden or hard-to-reach epitopes, and exhibits a high modularity for the development of complex structures.

Tuning the Biological Activity of Camphorimine Complexes through Metal Selection.

The cytotoxic activity of four sets of camphorimine complexes based on the Cu(I), Cu(II), Ag(I), and Au(I) metal sites were assessed against the cisplatin-sensitive A2780 and OVCAR3 ovarian cancer cells. The results showed that the gold complexes were ca. one order of magnitude more active than the silver complexes, which in turn were ca. one order of magnitude more active than the copper complexes. An important finding was that the cytotoxic activity of the Ag(I) and Au(I) camphorimine complexes was higher than that of cisplatin. Another relevant aspect was that the camphorimine complexes did not interact significantly with DNA, in contrast with cisplatin. The cytotoxic activity of the camphorimine complexes displayed a direct relationship with the cellular uptake by OVCAR3 cells, as ascertained by PIXE (particle-induced X-ray emission). The levels of ROS (reactive oxygen species) formation exhibited an inverse relationship with the reduction potentials for the complexes with the same metal, as assessed by cyclic voltammetry. In order to gain insight into the toxicity of the complexes, their cytotoxicity toward nontumoral cells (HDF and V79 fibroblasts) was evaluated. The in vivo cytotoxicity of complex 5 using the nematode Caenorhabditis elegans was also assessed. The silver camphorimine complexes displayed the highest selectivity coefficients (activity vs. toxicity).

Spontaneous Bacterial Peritonitis in Cirrhotic Patients: A Shift in the Microbial Pattern? A Retrospective Analysis.

Introduction: Over the last decade, a shift in the spontaneous bacterial peritonitis (SBP) microbial pattern toward an increasing incidence of gram-positive and multidrug-resistant (MDR) bacteria has been reported. Systematic surveillance of the local microbiological scenario and antibiotic resistance is crucial to SBP treatment success. The main objective of this study was to evaluate the microbiological profile and bacterial resistance of SBP pathogens in a Portuguese cohort to allow selection of the most appropriate empirical antibiotics. Methods: This is a single-center retrospective study including 63 adult cirrhotic patients with culture-positive SBP. Patients were identified using a hospital general diagnostic database and searching for all SBP events (neutrophil count in ascitic fluid ≥250/mm3) from January 1, 2012, to December 31, 2017. Patients were excluded if they had culture-negative SBP, secondary peritonitis, peritoneal dialysis, a liver transplant, or immunodeficiency. The site of SBP acquisition was classified as nosocomial if it was diagnosed 48 h or longer after hospitalization or as nonnosocomial if it was diagnosed within the first 48 h. MDR bacteria were those with an acquired resistance to at least 1 agent in 3 or more antimicrobial categories. All statistical analyses were carried out using IBM SPSS Statistics software version 22 (IBM, New York, USA). Results: The study cohort comprised 53 (84.1%) men. The mean age of the patients was 60.6 ± 11.2 years. Alcohol was the most common etiology (88.9%) and most patients had advanced liver cirrhosis (87.1%, Child C). Gram-negative bacteria were slightly more frequent than gram-positive bacteria (56.9 vs. 43.1%). Escherichia coli was the most common pathogen (33.8%). Nineteen (31.7%) bacteria were classified as MDR. Resistance to third-generation cephalosporins, quinolones, piperacillin-tazobactam, and carbapenems was found in 31.7, 35, 26.7, and 18.3% of the cases, respectively. The rates of gram-positive bacteria were similar between nosocomial and nonnosocomial episodes (45 vs. 42.2%; p = 0.835). MDR bacteria were more common in the nosocomial group (50 vs. 23.8%; p = 0.046). Resistance to third-generation cephalosporins (50 vs. 23.8%; p = 0.046), piperacillin-tazobactam (44.4 vs. 19.1%; p = 0.041), and carbapenems (33.3 vs. 11.9%; p = 0.049) occurred more frequently in nosocomial episodes. Resistance to first-line antibiotic occurred in 29.3% of the patients, being more common in the nosocomial group (44.4 vs. 22.5%; p = 0.089). Conclusion: Although gram-negative bacteria remain the most common causative microorganisms, our results emphasize the shift in SBP microbiological etiology, as almost half of the isolated microorganisms were gram positive. The emergence of bacteria resistant to traditionally recommended empirical antibiotics underlines the importance of basing this choice on local flora and antibiotic susceptibility data, allowing a more rational and successful use of antibiotics.

Introdução: Na última década assistiu-se a uma mudança no padrão microbiológico da peritonite bacteriana espontânea (PBE), com aumento da incidência de bactérias gram-positivas e multirresistentes. Uma vigilância sistemática do cenário microbiológico e da resistência antibiótica é crucial para o sucesso do tratamento da PBE. O principal objetivo deste estudo foi avaliar o perfil microbiológico e os padrões de resistência antibiótica dos agentes bacterianos responsáveis pelos casos de PBE numa coorte portuguesa de doentes cirróticos, de modo a permitir uma seleção mais apropriada da antibioterapia empírica. Métodos: Estudo retrospetivo unicêntrico, que incluiu 63 doentes adultos cirróticos com PBE culturapositiva. A identificação dos doentes foi efetuada a partir da base de dados eletrónica do centro hospitalar, pesquisando todos os internamentos por PBE (contagem de neutrófilos no líquido ascítico ≥250/mm3) entre 1 janeiro de 2012 e 31 de dezembro de 2017. Foram aplicados como critérios de exclusão: cultura de líquido ascítico negativa, peritonite secundária, diálise peritoneal, transplante hepático ou imunodeficiência. O local de aquisição da PBE foi classificado como nosocomial se diagnóstico após as primeiras 48 horas de hospitalização, e não-nosocomial se diagnóstico nas primeiras 48 horas. Multirresistência foi definida como resistência adquirida a pelo menos um agente em três ou mais categorias antimicrobianas. A análise estatística foi efetuada com recurso ao software IBM SPSS Statistics versão 22 (IBM, New York, USA). Resultados: A coorte incluiu 53 (84.1%) doentes cirróticos do género masculino. A idade média dos doentes foi de 60.6 ± 11.2 anos. O álcool constituiu a etiologia mais comum (88.9%) e a maioria dos doentes apresentava uma cirrose em estadio avançado (87.1%, Child-C). As bactérias gram-negativas revelaram-se ligeiramente mais frequentes que as gram-positivas (56.9 vs. 43.1%). Escherichia coli foi o microrganismo mais frequente (33.8%). Dezanove (31.7%) das bactérias isoladas foram classificadas como multirresistentes. As resistências às cefalosporinas de terceira-geração, às quinolonas, à piperacilina-tazobactam e aos carbapenemes foram de 31.7, 35, 26.7 e 18.3%, respetivamente. A taxa de bactérias gram-positivas foi similar entre PBE nosocomial e não-nosocomial (45 vs. 42.2%; p = 0.835). As bactérias multirresistentes foram mais frequentes no grupo nosocomial (50 vs. 23.8%; p = 0.046). A resistência às cefalosporinas de terceira-geração (50 vs. 23.8%; p = 0.046), à piperacilina-tazobactam (44.4 vs. 19.1%; p = 0.041) e aos carbapenemes (33.3 vs. 11.9%; p = 0.049) foi significativamente superior nas infeções nosocomiais. A resistência à antibioterapia empírica de primeira linha ocorreu em 29.3% dos doentes, sendo mais frequente no grupo nosocomial (44.4 vs. 22.5%; p = 0.089). Conclusão: Apesar de as bactérias gram-negativas constituírem, nesta coorte, a maioria dos microrganismos responsáveis pela PBE, os nossos resultados enfatizam a mudança na etiologia microbiológica da PBE, na medida em que, quase metade dos microrganismos isolados foram gram-positivos. A emergência de bactérias resistentes aos antibióticos empíricos tradicionalmente recomendados sublinha a importância de basear esta escolha nos dados locais sobre flora bacteriana e susceptibilidade antibiótica, permitindo uma escolha mais racional e um uso bem-sucedido dos antibióticos.

Broad Spectrum Functional Activity of Structurally Related Monoanionic Au(III) Bis(Dithiolene) Complexes.

The biological properties of sixteen structurally related monoanionic gold (III) bis(dithiolene/ diselenolene) complexes were evaluated. The complexes differ in the nature of the heteroatom connected to the gold atom (AuS for dithiolene, AuSe for diselenolene), the substituent on the nitrogen atom of the thiazoline ring (Me, Et, Pr, iPr and Bu), the nature of the exocyclic atom or group of atoms (O, S, Se, C(CN)2) and the counter-ion (Ph4P+ or Et4N+). The anticancer and antimicrobial activities of all the complexes were investigated, while the anti-HIV activity was evaluated only for selected complexes. Most complexes showed relevant anticancer activities against Cisplatin-sensitive and Cisplatin-resistant ovarian cancer cells A2780 and OVCAR8, respectively. After 48 h of incubation, the IC50 values ranged from 0.1-8 µM (A2780) and 0.8-29 µM (OVCAR8). The complexes with the Ph4P+ ([P]) counter-ion are in general more active than their Et4N+ ([N]) analogues, presenting IC50 values in the same order of magnitude or even lower than Auranofin. Studies in the zebrafish embryo model further showed that, despite their marked anticancer effect, the complexes with [P] counter-ion exhibited low in vivo toxicity. In general, the exocyclic exchange of sulfur by oxygen or ylidenemalononitrile (C(CN)2) enhanced the compounds toxicity. Most complexes containing the [P] counter ion exhibited exceptional antiplasmodial activity against the Plasmodium berghei parasite liver stages, with submicromolar IC50 values ranging from 400-700 nM. In contrast, antibacterial/fungi activities were highest for most complexes with the [N] counter-ion. Auranofin and two selected complexes [P][AuSBu(=S)] and [P][AuSEt(=S)] did not present anti-HIV activity in TZM-bl cells. Mechanistic studies for selected complexes support the idea that thioredoxin reductase, but not DNA, is a possible target for some of these complexes. The complexes [P] [AuSBu(=S)], [P] [AuSEt(=S)], [P] [AuSEt(=Se)] and [P] [AuSeiPr(=S)] displayed a strong quenching of the fluorescence intensity of human serum albumin (HSA), which indicates a strong interaction with this protein. Overall, the results highlight the promising biological activities of these complexes, warranting their further evaluation as future drug candidates with clinical applicability.

A Less Common Cause of Acute Hepatitis in Kidney Transplant Recipients: A Case Series.

BACKGROUND: Hepatitis E virus (HEV) is a cause of significant morbidity and mortality, representing an important global public health problem. Immunocompetent patients with acute hepatitis E can clear the infection spontaneously; however, in approximately two thirds of cases, immunosuppressed patients, such as kidney transplant (KT) recipients, fail to clear the HEV infection and develop chronic hepatitis. PATIENTS AND METHODS: We report 3 cases of HEV infection in KT patients. Two presented only with laboratory abnormalities and elevated liver enzymes, and 1 presented with symptomatic disease motivating hospital admission. None was able to clear the infection spontaneously, and they were all treated with ribavirin, accompanied with reduction of immunosuppressive drugs. Adverse effects of the treatment were reported in 2 patients, and in 1 case, a dose reduction was necessary. All patients responded to the treatment and have no current evidence of active disease. No alterations of basal kidney function during or related to the treatment were registered. DISCUSSION: HEV screening in KT patients presenting with abnormal liver function of undetermined cause is fundamental, as it might have poorer outcomes in this specific population. The treatment with ribavirin seems to be safe and effective, although we must always be alert to potential side effects, maintaining a close follow-up of these patients.

LipNanoCar Technology - A Versatile and Scalable Technology for the Production of Lipid Nanoparticles.

The extensive knowledge in the miniemulsion technique used in biocatalysis applications by the authors allowed the development of drug delivery systems that constitutes the LipNanoCar technology core for the production of lipid nanoemulsions and solid lipid nanoparticles. The LipNanoCar technology, together with adequate formulations of different oils, fatty acids, surfactants, and temperature, allows the entrapment of several bioactive and therapeutic compounds in lipid nanoparticles for cosmetic, nutrition, and pharmaceutical applications.The LIpNanoCar technology allowed lipid nanoparticles production with average sizes ranging from 100 to 300 nm and Zeta Potentials between -55 and -20 mV. Concomitantly, high entrapment or encapsulation efficiencies (%EE) were achieved, as illustrated in this work for ß-carotene and vitamins derivatives (>85%) for cosmetic application, and for antibiotics currently used in chemotherapy, like rifampicin (69-85%) and pyrazinamide (14-29%) against Mycobacterium tuberculosis (TB), and ciprofloxacin (>65%) and tobramycin (~100%) in Cystic Fibrosis (CF) respiratory infections therapy. Ciprofloxacin presented, for example, a quick-release from the lipid nanoparticles using a dialysis tubing (96% in the first 7 h), but slower than the free antibiotic (95% in the first 3 h). This result suggests that ciprofloxacin is loaded near the external surface of the lipid nanoparticles.The toxicity and validation of entrapment of antibiotics in lipid nanoparticles for Cystic Fibrosis therapy were assessed using Caenorhabditis elegans as an animal model of bacterial infection. Fluorescence microscopy of an entrapped fluorescent dye (DiOC) confirmed the uptake of the lipid nanoparticles by ingestion, and their efficacy was successfully tested in C. elegans. Burkholderia contaminans IST408 and Burkholderia cenocepacia K56-2 infections were tested as model bacterial pathogens difficult to eradicate in Cystic Fibrosis respiratory diseases.

Bioelectricity generation using long-term operated biocathode: RFLP based microbial diversity analysis.

In the present work, power generation and substrate removal efficiencies of long-term operated microbial fuel cells, containing abiotic cathodes and biocathodes, were evaluated for 220 days. Among the two microbial fuel cell (MFC) types, the one containing biocathode showed higher power density (54 mW/m2), current density (122 mA/m2) coulombic efficiency (33%), and substrate removal efficiency (94%) than the abiotic cathode containing MFC. Voltammetric analysis also witnessed higher and sustainable electron discharge for the MFC with biocathode, when compared with the abiotic cathode MFC. Over the tested period, both MFC have shown a cell voltage drop, after 150 and 165, days, for the MFC with biocathode and abiotic cathodes, respectively. Polymerase chain reaction (PCR) based restriction fragment length polymorphism (RFLP) analysis identified 281 clones. Bacteria belonging to Acinetobacter, Acidovorax, Pseudomonas and Burkholderia were observed in the abiotic cathode MFC. Bacteria belonging to Geobacter, Cupriavidus and Acidobacteria were observed in the biocathode MFC. Almost similar types of archaea (Methanosarcinales, Methanolinea, Nitrososphaera and Methanomicrobiales) were observed in both MFCs.

A Polyclonal Antibody Raised against the Burkholderia cenocepacia OmpA-like Protein BCAL2645 Impairs the Bacterium Adhesion and Invasion of Human Epithelial Cells In Vitro.

Respiratory infections by bacteria of the Burkholderia cepacia complex (Bcc) remain a life threat to cystic fibrosis (CF) patients, due to the faster lung function decline and the absence of effective eradication strategies. Immunotherapies are regarded as an attractive alternative to control and reduce the damages caused by these infections. In this work, we report the cloning and functional characterization of the OmpA-like BCAL2645 protein, previously identified and found to be immunoreactive against sera from CF patients with a record of Bcc infections. The BCAL2645 protein is shown to play a role in biofilm formation, adherence to mucins and invasion of human lung epithelial cells. The expression of the BCAL2645 protein was found to be increased in culture medium, mimicking the lungs of CF patients and microaerophilic conditions characteristic of the CF lung. Moreover, a polyclonal antibody raised against BCAL2645 was found to inhibit, by about 75 and 85%, the ability of B. cenocepacia K56-2 to bind and invade in vitro CFBE41o- human bronchial epithelial cells. These results highlight the potential of anti-BCAL2645 antibodies for the development of passive immunization therapies to protect CF patients against Bcc infections.

Synthesis and Characterization of Camphorimine Au(I) Complexes with a Remarkably High Antibacterial Activity towards B. contaminans and P. aeruginosa.

Fourteen new camphorimine Au(I) complexes were synthesized and characterized by spectroscopic (NMR, FTIR) and elemental analysis. The structural arrangement of three selected examples were computed by Density Functional Theory (DFT) showing that the complexes essentially keep the {AuI-CN} unit. The Minimum Inhibition Concentrations (MIC) were assessed for all complexes showing that they are active towards the Gram-negative strains E. coli ATCC25922, P. aeruginosa 477, and B. contaminans IST408 and the Gram-positive strain S. aureus Newman. The complexes display very high activity towards P. aeruginosa 477 and B. contaminans IST408 with selectivity towards B. contaminans. An inverse correlation between the MIC values and the gold content was found for B. contaminans and P. aeruginosa. However, plots of MIC values and Au content for P. aeruginosa 477 and B. contaminans IST408 follow distinct trends. No clear relationship could be established between the MIC values and the redox potentials of the complexes measured by cyclic voltammetry. The MIC values are essentially independent of the redox potentials either cathodic or anodic. The complexes K3[{Au(CN)2}3(A4L)] (8, Y = m-OHC6H4) and K3[{Au(CN)2}3(B2L)]·3H2O (14, Z = p-C6H4) display the lower MIC values for the two strains. In normal fibroblast cells, the IC50 values for the complexes are ca. one order of magnitude lower than their MIC values, although higher than that of the precursor KAu(CN)2.

Bacterial Nosocomial Infections: Multidrug Resistance as a Trigger for the Development of Novel Antimicrobials.

Nosocomial bacterial infections are associated with high morbidity and mortality, posing a huge burden to healthcare systems worldwide. The ongoing COVID-19 pandemic, with the raised hospitalization of patients and the increased use of antimicrobial agents, boosted the emergence of difficult-to-treat multidrug-resistant (MDR) bacteria in hospital settings. Therefore, current available antibiotic treatments often have limited or no efficacy against nosocomial bacterial infections, and novel therapeutic approaches need to be considered. In this review, we analyze current antibacterial alternatives under investigation, focusing on metal-based complexes, antimicrobial peptides, and antisense antimicrobial therapeutics. The association of new compounds with older, commercially available antibiotics and the repurposing of existing drugs are also revised in this work.

Immunization and Immunotherapy Approaches against Pseudomonas aeruginosa and Burkholderia cepacia Complex Infections.

Human infections caused by the opportunist pathogens Burkholderia cepacia complex and Pseudomonas aeruginosa are of particular concern due to their severity, their multiple antibiotic resistance, and the limited eradication efficiency of the current available treatments. New therapeutic options have been pursued, being vaccination strategies to prevent or limit these infections as a rational approach to tackle these infections. In this review, immunization and immunotherapy approaches currently available and under study against these bacterial pathogens is reviewed. Ongoing active and passive immunization clinical trials against P. aeruginosa infections is also reviewed. Novel identified bacterial targets and their possible exploitation for the development of immunization and immunotherapy strategies against P. aeruginosa and B. cepacia complex and infections are also presented and discussed.

Multiresistent Cupriavidus pauculus infection in an immunocompromised elderly patient.

Cupriavidus pauculus is a gram-negative bacillus aerobic bacteria widely distributed in nature that can cause, in rare cases, serious infections both in immunocompromised and immunocompetent patients. We describe a case of an elderly patient admitted in emergency room with septic shock and diagnosed with a urinary tract infection. During his hospital stay, his clinical and analytical conditions have deteriorated. Blood cultures were positive for C. pauculus only sensitive to minocycline. Despite every effort, due to multiple comorbidities and a nosocomial pneumonia, the patient ends up dying.