Rhein kills Actinobacillus pleuropneumoniae, reduces biofilm formation, and effectively treats bacterial lung infections in mice.

Background. Actinobacillus pleuropneumoniae, a member of the Pasteurellaceae family, is known for its highly infectious nature and is the primary causative agent of infectious pleuropneumonia in pigs. This disease poses a considerable threat to the global pig industry and leads to substantial economic losses due to reduced productivity, increased mortality rates, and the need for extensive veterinary care and treatment. Due to the emergence of multi-drug-resistant strains, Chinese herbal medicine is considered one of the best alternatives to antibiotics due to its unique mechanism of action and other properties. As a type of Chinese herbal medicine, Rhein has the advantages of a wide antibacterial spectrum and is less likely to develop drug resistance, which can perfectly solve the limitations of current antibacterial treatments.Methods. The killing effect of Rhein on A. pleuropneumoniae was detected by fluorescence quantification of differential expression changes of key genes, and scanning electron microscopy was used to observe the changes in A. pleuropneumoniae status after Rhein treatment. Establishing a mouse model to observe the treatment of Rhein after A. pleuropneumoniae infection.Results. Here, in this study, we found that Rhein had a good killing effect on A. pleuropneumoniae and that the MIC was 25 µg ml-1. After 3 h of action, Rhein (4×MIC) completely kills A. pleuropneumoniae and Rhein has good stability. In addition, the treatment with Rhein (1×MIC) significantly reduced the formation of bacterial biofilms. Therapeutic evaluation in a murine model showed that Rhein protects mice from A. pleuropneumoniae and relieves lung inflammation. Quantitative RT-PCR (Quantitative reverse transcription polymerase chain reaction is a molecular biology technique that combines both reverse transcription and polymerase chain reaction methods to quantitatively detect the amount of a specific RNA molecule) results showed that Rhein treatment significantly downregulated the expression of the IL-18 (Interleukin refers to a class of cytokines produced by white blood cells), TNF-α, p65 and p38 genes. Along with the downregulation of genes such as IL-18, it means that Rhein has an inhibitory effect on the expression of these genes, thereby reducing the activation of inflammatory cells and the production of inflammatory mediators. This helps reduce inflammation and protects tissue from further damage.Conclusions. This study reports the activity of Rhein against A. pleuropneumoniae and its mechanism, and reveals the ability of Rhein to treat A. pleuropneumoniae infection in mice, laying the foundation for the development of new drugs for bacterial infections.

Tea Polyphenols Protects Tracheal Epithelial Tight Junctions in Lung during Actinobacillus pleuropneumoniae Infection via Suppressing TLR-4/MAPK/PKC-MLCK Signaling.

Actinobacillus pleuropneumoniae (APP) is the causative pathogen of porcine pleuropneumonia, a highly contagious respiratory disease in the pig industry. The increasingly severe antimicrobial resistance in APP urgently requires novel antibacterial alternatives for the treatment of APP infection. In this study, we investigated the effect of tea polyphenols (TP) against APP. MIC and MBC of TP showed significant inhibitory effects on bacteria growth and caused cellular damage to APP. Furthermore, TP decreased adherent activity of APP to the newborn pig tracheal epithelial cells (NPTr) and the destruction of the tight adherence junction proteins ß-catenin and occludin. Moreover, TP improved the survival rate of APP infected mice but also attenuated the release of the inflammation-related cytokines IL-6, IL-8, and TNF-α. TP inhibited activation of the TLR/MAPK/PKC-MLCK signaling for down-regulated TLR-2, TLR4, p-JNK, p-p38, p-PKC-α, and MLCK in cells triggered by APP. Collectively, our data suggest that TP represents a promising therapeutic agent in the treatment of APP infection.

Beneficial or detrimental activity of regulatory T cells, indoleamine 2,3-dioxygenase, and heme oxygenase-1 in the lungs is influenced by the level of virulence of Mycobacterium tuberculosis strain infection.

Tuberculosis (TB) caused by the complex Mycobacterium tuberculosis (Mtb) is the main cause of death by a single bacterial agent. Last year, TB was the second leading infectious killer after SARS-CoV-2. Nevertheless, many biological and immunological aspects of TB are not completely elucidated, such as the complex process of immunoregulation mediated by regulatory T cells (Treg cells) and the enzymes indoleamine 2,3-dioxygenase (IDO) and heme oxygenase 1 (HO-1). In this study, the contribution of these immunoregulatory factors was compared in mice infected with Mtb strains with different levels of virulence. First Balb/c mice were infected by intratracheal route, with a high dose of mild virulence reference strain H37Rv or with a highly virulent clinical isolate (strain 5186). In the lungs of infected mice, the kinetics of Treg cells during the infection were determined by cytofluorometry and the expression of IDO and HO-1 by RT-PCR and immunohistochemistry. Then, the contribution of immune-regulation mediated by Treg cells, IDO and HO-1, was evaluated by treating infected animals with specific cytotoxic monoclonal antibodies for Treg cells depletion anti-CD25 (PC61 clone) or by blocking IDO and HO-1 activity using specific inhibitors (1-methyl-D,L-tryptophan or zinc protoporphyrin-IX, respectively). Mice infected with the mild virulent strain showed a progressive increment of Treg cells, showing this highest number at the beginning of the late phase of the infection (28 days), the same trend was observed in the expression of both enzymes being macrophages the cells that showed the highest immunostaining. Animals infected with the highly virulent strain showed lower survival (34 days) and higher amounts of Treg cells, as well as higher expression of IDO and HO-1 one week before. In comparison with non-treated animals, mice infected with strain H37Rv with depletion of Treg cells or treated with the enzymes blockers during late infection showed a significant decrease of bacilli loads, higher expression of IFN-g and lower IL-4 but with a similar extension of inflammatory lung consolidation determined by automated morphometry. In contrast, the depletion of Treg cells in infected mice with the highly virulent strain 5186 produced diffuse alveolar damage that was similar to severe acute viral pneumonia, lesser survival and increase of bacillary loads, while blocking of both IDO and HO-1 produced high bacillary loads and extensive pneumonia with necrosis. Thus, it seems that Treg cells, IDO and HO-1 activities are detrimental during late pulmonary TB induced by mild virulence Mtb, probably because these factors decrease immune protection mediated by the Th1 response. In contrast, Treg cells, IDO and HO-1 are beneficial when the infection is produced by a highly virulent strain, by regulation of excessive inflammation that produced alveolar damage, pulmonary necrosis, acute respiratory insufficiency, and rapid death.

Multistate Outbreak of Melioidosis Associated with Imported Aromatherapy Spray.

Melioidosis, caused by the bacterium Burkholderia pseudomallei, is an uncommon infection that is typically associated with exposure to soil and water in tropical and subtropical environments. It is rarely diagnosed in the continental United States. Patients with melioidosis in the United States commonly report travel to regions where melioidosis is endemic. We report a cluster of four non-travel-associated cases of melioidosis in Georgia, Kansas, Minnesota, and Texas. These cases were caused by the same strain of B. pseudomallei that was linked to an aromatherapy spray product imported from a melioidosis-endemic area.

Effects of repeated infections with non-typeable Haemophilus influenzae on lung in vitamin D deficient and smoking mice.

BACKGROUND: In chronic obstructive pulmonary disease (COPD), exacerbations cause acute inflammatory flare-ups and increase the risk for hospitalization and mortality. Exacerbations are common in all disease stages and are often caused by bacterial infections e.g., non-typeable Heamophilus influenzae (NTHi). Accumulating evidence also associates vitamin D deficiency with the severity of COPD and exacerbation frequency. However, it is still unclear whether vitamin D deficiency when combined with cigarette smoking would worsen and prolong exacerbations caused by repeated infections with the same bacterial strain. METHODS: Vitamin D sufficient (VDS) and deficient (VDD) mice were exposed to nose-only cigarette smoke (CS) for 14 weeks and oropharyngeally instilled with NTHi at week 6, 10 and 14. Three days after the last instillation, mice were assessed for lung function, tissue remodeling, inflammation and immunity. The impact of VDD and CS on inflammatory cells and immunoglobulin (Ig) production was also assessed in non-infected animals while serum Ig production against NTHi and dsDNA was measured in COPD patients before and 1 year after supplementation with Vitamin D3. RESULTS: VDD enhanced NTHi eradication, independently of CS and complete eradication was reflected by decreased anti-NTHi Ig's within the lung. In addition, VDD led to an increase in total lung capacity (TLC), lung compliance (Cchord), MMP12/TIMP1 ratio with a rise in serum Ig titers and anti-dsDNA Ig's. Interestingly, in non-infected animals, VDD exacerbated the CS-induced anti-NTHi Ig's, anti-dsDNA Ig's and inflammatory cells within the lung. In COPD patients, serum Ig production was not affected by vitamin D status but anti-NTHi IgG increased after vitamin D3 supplementation in patients who were Vitamin D insufficient before treatment. CONCLUSION: During repeated infections, VDD facilitated NTHi eradication and resolution of local lung inflammation through production of anti-NTHi Ig, independently of CS whilst it also promoted autoantibodies. In COPD patients, vitamin D supplementation could be protective against NTHi infections in vitamin D insufficient patients. Future research is needed to decipher the determinants of dual effects of VDD on adaptive immunity. TRAIL REGISTRATION: ClinicalTrials, NCT00666367. Registered 23 April 2008, https://www.clinicaltrials.gov/ct2/show/study/NCT00666367 .

Oral vaccination of piglets against Mycoplasma hyopneumoniae using silica SBA-15 as an adjuvant effectively reduced consolidation lung lesions at slaughter.

Mycoplasma (M.) hyopneumoniae is the main pathogen of porcine enzootic pneumonia (PEP). Its controlling is challenging, and requires alternative strategies. This study aimed to develop an oral vaccine against M. hyopneumoniae using a nanostructured mesoporous silica (SBA-15) as an adjuvant, and compare its effect with an intramuscular (IM) commercial vaccine (CV). Fifty 24 day-old M. hyopneumoniae-free piglets composed five equal groups for different immunization protocols, consisting of a CV and/or oral immunization (OI). Control piglets did not receive any form of immunization. All piglets were challenged with M. hyopneumoniae strain 232 on D49 by tracheal route. IgA antibody response in the respiratory tract, bacterial shedding and serum IgG were evaluated. The piglets were euthanized on 28 (D77) and 56 (D105) days post-infection. Lung lesions were macroscopically evaluated; lung fragments and bronchoalveolar fluid (BALF) were collected for estimation of bacterial loads by qPCR and/or histopathology examination. All immunization protocols induced reduction on Mycoplasma-like macroscopic lung lesions. IgA Ab responses anti-M. hyopneumoniae, the expression of IL-4 cytokine and a lower expression of IL-8 were induced by CV and OI vaccines, while IgG was induced only by CV. Oral immunization using silica as a carrier-adjuvant can be viable in controlling M. hyopneumoniae infection.

Evaluation of Berberine as an Adjunct to TB Treatment.

Tuberculosis (TB) is the global health problem with the second highest number of deaths from a communicable disease after COVID-19. Although TB is curable, poor health infrastructure, long and grueling TB treatments have led to the spread of TB pandemic with alarmingly increasing multidrug-resistant (MDR)-TB prevalence. Alternative host modulating therapies can be employed to improve TB drug efficacies or dampen the exaggerated inflammatory responses to improve lung function. Here, we investigated the adjunct therapy of natural immune-modulatory compound berberine in C57BL/6 mouse model of pulmonary TB. Berberine treatment did not affect Mtb growth in axenic cultures; however, it showed increased bacterial killing in primary murine bone marrow-derived macrophages and human monocyte-derived macrophages. Ad libitum berberine administration was beneficial to the host in combination with rifampicin and isoniazid. Berberine adjunctive treatment resulted in decreased lung pathology with no additive or synergistic effects on bacterial burdens in mice. Lung immune cell flow cytometry analysis showed that adjunctive berberine treatment decreased neutrophil, CD11b+ dendritic cell and recruited interstitial macrophage numbers. Late onset of adjunctive berberine treatment resulted in a similar phenotype with consistently reduced numbers of neutrophils both in lungs and the spleen. Together, our results suggest that berberine can be supplemented as an immunomodulatory agent depending on the disease stage and inflammatory status of the host.

Anti-inflammatory and antibacterial activities of Pyrrosia petiolosa ethyl acetate (PPEAE) against Staphylococcus aureus in mice.

P. petiolosa as a typical Chinese herbal medicine has been generally utilized as Chinese native medicine formulation for treatment of chronic bronchitis, bronchial asthma and pneumoconiosis. The objective of this study was to evaluate the anti-inflammatory and antibacterial activities of P. petiolosa ethyl acetate extract (PPEAE) against S. aureusin mice. In our study, mice were infected pneumonia by S. aureus, colonization of S. aureus in lung tissue was calculated and the number of white blood cells (WBC) in blood was measured. Meanwhile, the hematoxylin-eosin staining (H&E) was observed and the Real-time PCR was employed to determine the relative mRNA expression. The results showed that, after treated with PPEAE the wet/dry (W/D) weight ratio and the number of WBC decreased dramatically, the number of S. aureus was significantly reduced. Furthermore, H&E staining showed that PPEAE obviously relieved the inflammation of infected mice and real-time PCR results indicated that PPEAE significantly down regulated the inflammatory iNOS, TNF-α and up regulated the anti-inflammatory HO-1 mRNA. In summary, our study revealed that application of crude product PPEAE had prominent antibacterial activity against S. aureus. PPEAE significantly reduced the biomass of S. aureus and effectively relieved the inflammation of S. aureus-induced pneumonia.

mSphere of Influence: Forgotten Questions.

Laura-Isobel McCall studies the relationship between location and disease pathogenesis, with a focus on infectious diseases and neglected diseases of poverty. In this mSphere of Influence article, she reflects on how three papers, "Opposing effects of fasting metabolism on tissue tolerance in bacterial and viral inflammation" (A. Wang, S. C. Huen, H. H. Luan, S. Yu, et al., Cell 166:1512-1525.e12, 2016, https://doi.org/10.1016/j.cell.2016.07.026), "Three-dimensional microbiome and metabolome cartography of a diseased human lung" (N. Garg, M. Wang, E. Hyde, R. R. da Silva, et al., Cell Host Microbe 22:705-716.e4, 2017, https://doi.org/10.1016/j.chom.2017.10.001), and "'It's like a phantom disease': patient perspectives on access to treatment for Chagas disease in the United States" (C. J. Forsyth, S. Hernandez, C. A. Flores, M. F. Roman, et al., Am J Trop Med Hyg 98:735-741, 2018, https://doi.org/10.4269/ajtmh.17-0691), shaped her spatial approach to infectious disease pathogenesis and helped her broaden her perspective from a pathogen-centric focus to a holistic view that include diseases tolerance mechanisms and barriers to health care access.

Longer-Term Omega-3 LCPUFA More Effective Adjunct Therapy for Tuberculosis Than Ibuprofen in a C3HeB/FeJ Tuberculosis Mouse Model.

Advancement in the understanding of inflammation regulation during tuberculosis (TB) treatment has led to novel therapeutic approaches being proposed. The use of immune mediators like anti-inflammatory and pro-resolving molecules for such, merits attention. Drug repurposing is a widely used strategy that seeks to identify new targets to treat or manage diseases. The widely explored nonsteroidal anti-inflammatory drug (NSAID) ibuprofen and a more recently explored pharmaconutrition therapy using omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs), have the potential to modulate the immune system and are thus considered potential repurposed drugs in this context. These approaches may be beneficial as supportive therapy to the already existing treatment regimen to improve clinical outcomes. Here, we applied adjunct ibuprofen and n-3 LCPUFA therapy, respectively, with standard anti-TB treatment, in a C3HeB/FeJ murine model of TB. Bacterial loads, lung pathology, lung cytokines/chemokines and lung lipid mediators were measured as outcomes. Lung bacterial load on day 14 post-treatment (PT) was lower in the n-3 LCPUFA, compared to the ibuprofen group (p = 0.039), but was higher in the ibuprofen group than the treated control group (p = 0.0315). Treated control and ibuprofen groups had more free alveolar space initially as compared to the n-3 LCPUFA group (4 days PT, p= 0.0114 and p= 0.002, respectively); however, significantly more alveolar space was present in the n-3 LCPUFA group as compared to the ibuprofen group by end of treatment (14 days PT, p = 0.035). Interleukin 6 (IL-6) was lower in the ibuprofen group as compared to the treated control, EPA/DHA and untreated control groups at 4 days PT (p = 0.019, p = 0.019 and p = 0.002, respectively). Importantly, pro-resolving EPA derived 9-HEPE, 11-HEPE, 12-HEPE and 18-HEPE lipid mediators (LMs) were significantly higher in the EPA/DHA group as compared to the ibuprofen and treated control groups. This suggests that n-3 LCPUFAs do improve pro-resolving and anti-inflammatory properties in TB, and it may be safe and effective to co-administer as adjunct therapy with standard TB treatment, particularly longer-term. Also, our results show host benefits upon short-term co-administration of ibuprofen, but not throughout the entire TB treatment course.

Adhatoda Vasica attenuates inflammatory and hypoxic responses in preclinical mouse models: potential for repurposing in COVID-19-like conditions.

BACKGROUND: COVID-19 pneumonia has been associated with severe acute hypoxia, sepsis-like states, thrombosis and chronic sequelae including persisting hypoxia and fibrosis. The molecular hypoxia response pathway has been associated with such pathologies and our recent observations on anti-hypoxic and anti-inflammatory effects of whole aqueous extract of Adhatoda Vasica (AV) prompted us to explore its effects on relevant preclinical mouse models. METHODS: In this study, we tested the effect of whole aqueous extract of AV, in murine models of bleomycin induced pulmonary fibrosis, Cecum Ligation and Puncture (CLP) induced sepsis, and siRNA induced hypoxia-thrombosis phenotype. The effect on lung of AV treated naïve mice was also studied at transcriptome level. We also determined if the extract may have any effect on SARS-CoV2 replication. RESULTS: Oral administration AV extract attenuates increased airway inflammation, levels of transforming growth factor-ß1 (TGF-ß1), IL-6, HIF-1α and improves the overall survival rates of mice in the models of pulmonary fibrosis and sepsis and rescues the siRNA induced inflammation and associated blood coagulation phenotypes in mice. We observed downregulation of hypoxia, inflammation, TGF-ß1, and angiogenesis genes and upregulation of adaptive immunity-related genes in the lung transcriptome. AV treatment also reduced the viral load in Vero cells infected with SARS-CoV2. CONCLUSION: Our results provide a scientific rationale for this ayurvedic herbal medicine in ameliorating the hypoxia-hyperinflammation features and highlights the repurposing potential of AV in COVID-19-like conditions.

The Manipulation of the Lipid Mediator Metabolism as Adjunct Host-Directed Therapy in Tuberculosis.

Host-directed therapies (HDTs) enhance the host response to tuberculosis (TB) infection to reduce disease severity. For instance, the manipulation of lipid mediator production diminishes the hyperactive immune response which is a known pathological feature of TB that generates lung tissue damage. Non-steroidal anti-inflammatory drugs (NSAIDs) and omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) are examples of such HDTs. In this mini-review, we recapitulate the literature available on the effects of NSAIDs and n-3 LCPUFA in TB as well as the immunological pathways underpinning these effects. Many NSAIDs have a great deal of data describing their effects and safety and in many jurisdictions are inexpensive, and sold over the counter in neighborhood convenience stores and supermarkets. The potential benefits of NSAIDs in TB are well-documented in pre-clinical studies. The reduction of pro-inflammatory lipid mediator production by inhibiting cyclooxygenase (COX) pathways with NSAIDs has been found to improve lung histopathology, bacterial control, and survival. Additionally, n-3 LCPUFA and its novel bioactive metabolites produced by COX and lipoxygenase (LOX) have been identified as safe and effective pro-resolving and antibacterial pharmaconutrients. Nevertheless, heterogeneous results have been reported in pre-clinical TB studies. Recently, the importance of the correct timing of NSAIDs and n-3 LCPUFA administration in TB has also been highlighted. This mini-review will provide a better understanding of the potential contribution of these therapies toward reducing inflammatory lung damage and improving bactericidal activity, especially during later stages of TB infection. It further highlights that clinical trials are required to confirm benefit and safety in TB patients.

Ceftolozane/tazobactam for Pseudomonas aeruginosa pulmonary exacerbations in cystic fibrosis adult patients: a case series.

Management of cystic fibrosis (CF) patients colonized with Pseudomonas aeruginosa is challenging due to its virulence and multi-drug resistance. Ceftolozane/tazobactam (C/T) is a promising new antipseudomonal agent, and clinical data on CF are limited. We describe our experience in the use of C/T for P. aeruginosa-related pulmonary exacerbations (PE) in CF adults admitted within 2016 and 2019 at Careggi Hospital, Florence, Italy. PE was diagnosed as deterioration of respiratory function, worsening cough, and increasing of sputum. C/T was given at the dose of 3 g every 8 h. C/T was used in ten patients. Mean length of C/T treatment was 16.3 days, and tobramycin was the most frequently combined antipseudomonal agent. All patients were successfully treated although susceptibility testing on sputum sample showed C/T resistance in two cases. No adverse effects related to C/T were reported. To our knowledge this is the largest case series on CF patients treated with C/T. Clinical responses were encouraging even where C/T resistant P. aeruginosa was isolated, probably due to multiple phenotypes colonizing CF lungs. C/T could play a promising role in combination therapy against P. aeruginosa as a part of a colistin-sparing regime.

Effect of Qingfei Huatan Huoxue Decoction combined with azithromycin on pulmonary function and inflammatory factors in children with Mycoplasma pneumonia.

To investigate the effect of Qingfei Huatan Huoxue Decoction combined with azithromycin on pulmonary function and inflammatory factors in children with Mycoplasma pneumonia. A total of 155 children with Mycoplasma pneumonia of toxic heat blocking lung syndrome were randomly divided into the control group (n=77) and the observation group (n=78) from March 2020 to March 2021. Both groups of children were given conventional treatment and azithromycin intravenous drip and the observation group was additionally given oral administration of Qingfei Huatan Huoxue Decoction, with 7 days as a course of treatment totaling 2 courses. The lung function, inflammatory factor level, immune function and coagulation function were compared between the two groups before and after treatment. After treatment, the symptom integral of fever, cough and pulmonary wet rales in the two groups were reduced, while FEV1, PEF and FEV1/ FVC were significantly increased, serum TNF-α, IFN- γ and IL-6 were significantly reduced, the levels of Immunoglobulin M (IgM), IgG and IgA were significantly reduced and plasma PT and APTT were significantly reduced, with more significant changes observed in the observation group (all P<0.05). The disappearance time of fever, cough and pulmonary moist rales in the observation group was significantly shorter than that in the control group (P<0.05). The recovery rate of the observation group was significantly higher than that of the control group (P<0.05). Qingfei Huatan Huoxue Decoction combined.

Proteomic and mechanistic study of Qingxuan Tongluo formula and curcumin in the treatment of Mycoplasma pneumoniae pneumonia.

OBJECTIVE: Mycoplasma pneumoniae (MP) is the only pathogen in the Mycoplasma family that can cause respiratory symptoms, including acute upper respiratory tract infection and bronchitis, which are often attributed to Mycoplasma pneumoniae pneumonia (MPP). MPP is one of the diseases that commonly affects the pediatric respiratory system, but its pathogenesis is unclear. This study investigated the therapeutic effects and mechanisms of Qingxuan Tongluo formula and its main component, curcumin, on MPP. METHODS: A mouse model of MPP was obtained by nasal drip of the MP strain. The effects of Qingxuan Tongluo formula and curcumin on the treatment of MPP were studied. The proteomic profiles of the alveolar lavage fluid of mice in the model group, Qingxuan Tongluo formula group and curcumin group were evaluated by LC-MS/MS. ELISA and immunohistochemistry were used to verify the possible presence of MP infection biomarkers and drug target proteins. RESULTS: Compared with the mice in the model group, the MPP mice in the Qingxuan Tongluo formula group had significantly reduced fever and cough and prolonged the cough incubation period. Moreover, the pulmonary pathology of the MPP mice was significantly improved, and the lung histopathological score was decreased. After treatment with Qingxuan Tongluo formula and curcumin, the functional and pathway abnormalities caused by MP were mainly inhibited. Levels of HSP90AA1, GRP94, ENO1 and PLG expression were verified by ELISA and immunohistochemistry. CONCLUSION: Qingxuan Tongluo formula significantly reduced fevers and cough and prolonged the cough incubation period of MPP mice. Qingxuan Tongluo formula and curcumin significantly improved the pathological changes in lung tissue caused by MP infection. Proteomics analyses indicated that Qingxuan Tongluo formula and curcumin may have therapeutic effects on MPP by regulating energy metabolism, relieving oxidative stress and activating the fibrinolytic system. ENO1 and PLG were found to be potential drug targets.

Influenza virus infection augments susceptibility to respiratory Yersinia pestis exposure and impacts the efficacy of antiplague antibiotic treatments.

Various respiratory viral infections in general and seasonal influenza in particular may increase the susceptibility to bacterial infections. Plague caused by Yersinia pestis endangers large populations during outbreaks or bioterrorism attacks. Recommended antibiotic countermeasures include well-established protocols based on animal studies and corroborated by effective treatment of human cases. Until now, prior exposure to viral respiratory infections was not taken into consideration when selecting the appropriate treatment for plague. Here, we show that as late as 25 days after exposure to influenza virus, convalescent mice still exhibited an increased susceptibility to sublethal doses of Y. pestis, presented with aberrant cytokine expression, and impaired neutrophil infiltration in the lungs. Increased levels of M2 alveolar macrophages and type II epithelial cells, as well as induction in metalloproteases expression and collagen and laminin degradation, suggested that the previous viral infection was under resolution, correlating with enhanced susceptibility to plague. Surprisingly, postexposure prophylaxis treatment with the recommended drugs revealed that ciprofloxacin was superior to doxycycline in mice recovering from influenza infection. These results suggest that after an influenza infection, the consequences, such as impaired immunity and lung tissue remodeling and damage, should be considered when treating subsequent Y. pestis exposure.

In vivo bactericidal effect of colistin-linezolid combination in a murine model of MDR and XDR Acinetobacter baumannii pneumonia.

Recently, paradoxical combinations of colistin with anti-Gram-positive bacterial agents were introduced as a treatment alternative for multidrug-resistant Acinetobacter baumannii (MDRAB) infection. We assessed the therapeutic efficacy of the colistin-linezolid combination regimen in vitro and in a murine model of Acinetobacter baumannii pneumonia. A multidrug-resistant clinical strain (MDRAB31) and an extensively drug-resistant clinical strain (XDRAB78) were used in this study. The survival rates of mice and bacterial counts in lung tissue were used to assess the effects of colistin-linezolid combination. The survival rates of colistin-linezolid combination groups significantly increased compared with colistin groups for MDRAB31 (72% versus 32%, P = 0.03) and for XDRAB78 (92% versus 68%, P = 0.031). The colistin-linezolid combination groups significantly reduced the bacterial counts in lung tissue compared with colistin groups for MDRAB31 and for XDRAB78 (P < 0.05). The colistin-linezolid combination had a bactericidal and synergistic effect compared with colistin alone in time-kill assay and in murine model of pneumonia. Our data demonstrated the synergistic effect of colistin-linezolid combination regimen as a treatment alternative for the severe pulmonary infection caused by MDRAB and XDRAB.

Overexpression of the celA1 gene in BCG modifies surface pellicle, glucosamine content in biofilms, and affects in vivo replication.

Biofilm formed in vitro by mycobacteria has been associated with increased antibiotic tolerance as compared with planktonic cells. Cellulose has been identified as a component of DTT-exposed biofilms formed by M. tuberculosis. The celA1 gene of M. tuberculosis encodes a cellulase, which could affect the formation of biofilm by slow-growing mycobacteria. In this work, the celA1 gene of M. tuberculosis was cloned into the integrative pMV361 plasmid and then transformed into M. bovis BCG Pasteur to produce BCG:celA1, to have celA1 expressed from the strong promoter hsp60. We compared planktonic and biofilm growth, possible presence of CelA1 in whole protein extracts, quantitated biofilm, presence of monosaccharides, and bacillary burden in lungs after aerosol infection in BALB/c mice. Differences in the appearance of the surface pellicle and of the biofilm attached to the substrate were observed. In biofilms, we observed a significant decrease of glucosamine in BCG:celA1 compared with BCG:pMV361. Finally, BCG:celA1 had lower viable bacteria than the BCG:pMV361 strain after 24 h and 3 weeks post-infection, but no difference was found at 9 weeks post-infection.

Omega-3 Fatty Acid and Iron Supplementation Alone, but Not in Combination, Lower Inflammation and Anemia of Infection in Mycobacterium tuberculosis-Infected Mice.

Progressive inflammation and anemia are common in tuberculosis (TB) and linked to poor clinical outcomes. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have inflammation-resolving properties, whereas iron supplementation in TB may have limited efficacy and enhance bacterial growth. We investigated effects of iron and EPA/DHA supplementation, alone and in combination, on inflammation, anemia, iron status markers and clinical outcomes in Mycobacterium tuberculosis-infected C3HeB/FeJ mice. One week post-infection, mice received the AIN-93 diet without (control) or with supplemental iron (Fe), EPA/DHA, or Fe+EPA/DHA for 3 weeks. Mice supplemented with Fe or EPA/DHA had lower soluble transferrin receptor, ferritin and hepcidin than controls, but these effects were attenuated in Fe+EPA/DHA mice. EPA/DHA increased inflammation-resolving lipid mediators and lowered lung IL-1α, IFN-γ, plasma IL-1ß, and TNF-α. Fe lowered lung IL-1α, IL-1ß, plasma IL-1ß, TNF-α, and IL-6. However, the cytokine-lowering effects in the lungs were attenuated with Fe+EPA/DHA. Mice supplemented with EPA/DHA had lower lung bacterial loads than controls, but this effect was attenuated in Fe+EPA/DHA mice. Thus, individually, post-infection EPA/DHA and iron supplementation lowered systemic and lung inflammation and mitigated anemia of infection in TB, but not when combined. EPA/DHA also enhanced bactericidal effects and could support inflammation resolution and management of anemia.

Fatal respiratory infection due to ST308 VIM-1-producing Pseudomonas aeruginosa in a lung transplant recipient: case report and review of the literature.

BACKGROUND: Data regarding the prevalence of metallo-ß-lactamases (MBLs) among Pseudomonas aeruginosa isolates in cystic fibrosis patients are scarce. Furthermore, there is limited knowledge on the effect of MBL production on patient outcomes. Here we describe a fatal respiratory infection due to P. aeruginosa producing VIM-type MBLs in a lung transplant recipient and the results of the subsequent epidemiological investigation. CASE PRESENTATION: P. aeruginosa isolates collected in the index patient and among patients temporally or spatially linked with the index patient were analyzed in terms of antibiotic susceptibility profile and MBL production. Whole-genome sequencing and phylogenetic reconstruction were also performed for all P. aeruginosa isolates producing VIM-type MBLs. A VIM-producing P. aeruginosa strain was identified in a lung biopsy of a lung transplant recipient with cystic fibrosis. The strain was VIM-1-producer and belonged to the ST308. Despite aggressive treatment, the transplant patient succumbed to the pulmonary infection due to the ST308 strain. A VIM-producing P. aeruginosa strain was also collected from the respiratory samples of a different cystic fibrosis patient attending the same cystic fibrosis center. This isolate harbored the blaVIM-2 gene and belonged to the clone ST175. This patient did not experience an adverse outcome. CONCLUSIONS: This is the first description of a fatal infection due to P. aeruginosa producing VIM-type MBLs in a lung transplant recipient. The circulation of P. aeruginosa isolates harboring MBLs pose a substantial risk to the cystic fibrosis population due to the limited therapeutic options available and their spreading potential.