Differential effects of beta-lactams on human IFN-gamma activity

Ceftazidime reduces cellular Skp2 to promote type-I interferon activity

Skp2 plays multiple roles in malignant tumours. Here, we revealed that Skp2 negatively regulates type-I interferon (IFN-I)-mediated antiviral activity. We first noticed that Skp2 can promote virus infection in cells. Further studies demonstrated that Skp2 interacts with IFN-I receptor 2 (IFNAR2) and promotes K48-linked polyubiquitination of IFNAR2, which accelerates the degradation of IFNAR2 proteins. Skp2-mediated downregulation of IFNAR2 levels inhibits IFN-I signalling and IFN-I-induced antiviral activity. In addition, we uncovered for the first time that the antibiotic ceftazidime can act as a repressor of Skp2. Ceftazidime reduces cellular Skp2 levels, thus enhancing IFNAR2 stability and IFN-I antiviral activity. This study reveals a new role of Skp2 in regulating IFN-I signalling and IFN-I antiviral activity and reports the antibiotic ceftazidime as a potential repressor of Skp2.

Antibiotic Resistance to Mycobacterium tuberculosis and Potential Use of Natural and Biological Products as Alternative Anti-Mycobacterial Agents

Background: Tuberculosis (TB) is an infectious disease caused by the bacillus Mycobacterium tuberculosis (Mtb). TB treatment is based on the administration of three major antibiotics: isoniazid, rifampicin, and pyrazinamide. However, multi-drug resistant (MDR) Mtb strains are increasing around the world, thus, allowing TB to spread around the world. The stringent response is demonstrated by Mtb strains in order to survive under hostile circumstances, even including exposure to antibiotics. The stringent response is mediated by alarmones, which regulate bacterial replication, transcription and translation. Moreover, the Mtb cell wall contributes to the mechanism of antibiotic resistance along with efflux pump activation and biofilm formation. Immunity over the course of TB is managed by M1-macrophages and M2-macrophages, which regulate the immune response against Mtb infection, with the former exerting inflammatory reactions and the latter promoting an anti-inflammatory profile. T helper 1 cells via secretion of interferon (IFN)-gamma, play a protective role in the course of TB, while T regulatory cells secreting interleukin 10, are anti-inflammatory. Alternative therapeutic options against TB require further discussion. In view of the increasing number of MDR Mtb strains, attempts to replace antibiotics with natural and biological products have been object of intensive investigation. Therefore, in this review the anti-Mtb effects exerted by probiotics, polyphenols, antimicrobial peptides and IFN-gamma will be discussed. All the above cited compounds are endowed either with direct antibacterial activity or with anti-inflammatory and immunomodulating characteristics.

Cefiderocol Protects against Cytokine- and Endotoxin-Induced Disruption of Vascular Endothelial Cell Integrity in an In Vitro Experimental Model

The severe course of bloodstream infections with Gram-negative bacilli can lead to organ dysfunctions and compromise the integrity of the vascular barrier, which are the hallmarks of sepsis. This study aimed to investigate the potential effect of cefiderocol on the barrier function of vascular endothelial cells (vECs) in an in vitro experimental set-up. Human umbilical vein cells (HUVECs), co-cultured with erythrocyte-depleted whole blood for up to 48 h, were activated with tumor necrosis factor-alpha (TNF-α) or lipopolysaccharide (LPS) to induce endothelial damage in the absence or presence of cefiderocol (concentrations of 10, 40 and 70 mg/L). The endothelial integrity was quantified using transendothelial electrical resistance (TEER) measurement, performed at 0, 3, 24 and 48 h after stimulation. Stimulation with TNF-α and LPS increased the endothelial permeability assessed by TEER at 24 and 48 h of co-culture. Furthermore, cefiderocol reduces interleukin-6 (IL-6), interleukin-1β (IL-1β) and TNF-α release in peripheral blood mononuclear cells (PBMCs) following LPS stimulation in a dose-dependent manner. Collectively, the data suggest that cefiderocol may have an influence on the cellular immune response and might support the maintenance of vEC integrity during inflammation associated with infection with Gram-negative bacteria, which warrants further investigations.

Simultaneous studies of gene expression and alternative polyadenylation in primary human immune cells

Transcription termination in eukaryotic cells involves the recognition of polyadenylation signals (PAS) that signal the site of pre-mRNA cleavage and polyadenylation. Most eukaryotic genes contain multiple PAS that are used by alternative polyadenylation (APA), a co-transcriptional process that increases transcriptomic diversity and modulates the fate of the mRNA and protein produced. However, current tools to pinpoint the relationship between mRNAs in different subcellular fractions and the gene expression outcome are lacking, particularly in primary human immune cells, which, due to their nature, are challenging to study. Here, we describe an integrative approach using subcellular fractionation and RNA isolation, chromatin-bound and nucleoplasmic RNA-Sequencing, 3' RNA-Sequencing and bioinformatics, to identify accurate APA mRNA isoforms and to quantify gene expression in primary human macrophages. Our protocol includes macrophage differentiation and polarization, co-culture with cancer cells, and gene silencing by siRNA. This method allows the simultaneous identification of macrophage APA mRNA isoforms integrated with the characterization of nuclear APA events, the identification of the molecular mechanisms involved, as well as the gene expression alterations caused by the cancer-macrophage crosstalk. With this methodology we identified macrophage APA mRNA signatures driven by the cancer cells that alter the macrophage inflammatory and transcriptomic profiles, with consequences for macrophage physiology and tumor evasion.

Selective toxicity of antibacterial agents-still a valid concept or do we miss chances and ignore risks?

BACKGROUND

Selective toxicity antibacteribiotics is considered to be due to interactions with targets either being unique to bacteria or being characterized by a dichotomy between pro- and eukaryotic pathways with high affinities of agents to bacterial- rather than eukaryotic targets. However, the theory of selective toxicity oversimplifies the complex modes of action of antibiotics in pro- and eukaryotes.

METHODS AND OBJECTIVE

This review summarizes data describing multiple modes of action of antibiotics in eukaryotes.

RESULTS

Aminoglycosides, macrolides, oxazolidinones, chloramphenicol, clindamycin, tetracyclines, glycylcyclines, fluoroquinolones, rifampicin, bedaquillin, ß-lactams inhibited mitochondrial translation either due to binding to mitosomes, inhibition of mitochondrial RNA-polymerase-, topoisomerase 2ß-, ATP-synthesis, transporter activities. Oxazolidinones, tetracyclines, vancomycin, ß-lactams, bacitracin, isoniazid, nitroxoline inhibited matrix-metalloproteinases (MMP) due to chelation with zinc and calcium, whereas fluoroquinols fluoroquinolones and chloramphenicol chelated with these cations, too, but increased MMP activities. MMP-inhibition supported clinical efficacies of ß-lactams and daptomycin in skin-infections, and of macrolides, tetracyclines in respiratory-diseases. Chelation may have contributed to neuroprotection by ß-lactams and fluoroquinolones. Aminoglycosides, macrolides, chloramphenicol, oxazolidins oxazolidinones, tetracyclines caused read-through of premature stop codons. Several additional targets for antibiotics in human cells have been identified like interaction of fluoroquinolones with DNA damage repair in eukaryotes, or inhibition of mucin overproduction by oxazolidinones.

CONCLUSION

The effects of antibiotics on eukaryotes are due to identical mechanisms as their antibacterial activities because of structural and functional homologies of pro- and eukaryotic targets, so that the effects of antibiotics on mammals are integral parts of their overall mechanisms of action.

Anti-Staphylococcus aureus single-chain variable region fragments provide protection against mastitis in mice

Staphylococcus aureus is a leading causative agent of bovine mastitis, which can result in significant economic losses to the dairy industry. However, available vaccines against bovine mastitis do not confer adequate protection, although passive immunization with antibodies may be useful to prevent disease. Hence, we constructed a bovine single-chain variable region fragment (scFv) phage display library using cDNAs from peripheral blood lymphocytes of cows with S. aureus-induced mastitis. After four rounds of selection, eight scFvs that bound S. aureus antigens with high affinity were obtained. The framework regions of the variable domains (VH and VL) of the eight scFvs were highly conserved, and the complementarity-determining regions (CDRs) displayed significant diversity, especially CDR3 of the VH domain. All eight scFvs inhibited S. aureus growth in culture medium. Lactating mice were challenged by injecting S. aureus into the fourth mammary gland. Histopathological analysis showed that treatment with these scFvs prior to bacterial challenge maintained the structure of the mammary acini, decreased infiltration of polymorphonuclear neutrophils, increased levels of interferon-gamma and interleukin-4, and reduced tumor necrosis factor-alpha levels in mammary tissues, as compared with mice treatment with physiological saline (P < 0.05). These novel bovine scFvs may be suitable candidates for therapeutic agents for the prevention of S. aureus-induced bovine mastitis.

Effect of Antibiotic Class on Stroke Outcome

BACKGROUND AND PURPOSE

Infections are common after stroke and associated with worse outcome. Clinical trials evaluating the benefit of prophylactic antibiotics have produced mixed results. This study explores the possibility that antibiotics of different classes may differentially affect stroke outcome.

METHODS

Lewis rats were subjected to transient cerebral ischemia (2 hours) and survived for 1 month. The day after stroke they were randomized to therapy with ceftiofur (a β-lactam antibiotic), enrofloxacin (a fluoroquinolone antibiotic), or vehicle (as controls) and underwent the equivalent of 7 days of treatment. Behavioral tests were performed weekly until euthanization. In a subset of animals, histology was done.

RESULTS

There were no differences in outcomes at 24 hours or 1 week after stroke among the different groups. At 1 month after stroke, however, performance on the rotarod was worse in enrofloxacin-treated animals when compared with control animals.

CONCLUSIONS

Independent of infection, the antibiotic enrofloxacin was associated with worse stroke outcome. These data echo the clinical observations to date and suggest that the secondary effects of antibiotics on stroke outcome should be considered when treating infection in subjects with stroke. The mechanism by which this antibiotic affects outcome needs to be elucidated.

Maternal history of autoimmune disease and later development of tourette syndrome in offspring

OBJECTIVE

In a nationwide prospective cohort study, we examined the possible association between maternal autoimmune disease (AD) and later diagnosis of Tourette syndrome (TS) in offspring.

METHOD

Data from national Danish health registers identified a cohort consisting of all children born in Denmark between 1990 and 2007 (n = 1,116,255), followed prospectively from birth until 2011, date of TS diagnosis, death, or emigration/disappearance, whichever came first. The incidence rate ratio (IRR) of TS, dependent on whether or not the mother had a prior diagnosis of AD, was estimated by Poisson regression with 95% CIs and adjusted for age, calendar time, place of birth, maternal and paternal age, parental psychiatric diagnoses other than TS, and parental TS.

RESULTS

The cohort contributed a total of 13,000,162 person years and 2,442 participants with a diagnosis of TS (414 females and 2,028 males). Prior maternal AD was found in 110 of the 2,442 children with TS, corresponding to an increased risk of TS, with an adjusted IRR of 1.22 (95% CI = 1.01-1.48). Maternal history of a prior AD increased the risk of TS in males, with an adjusted IRR of 1.29 (95% CI = 1.05-1.58), but not in females, with an adjusted IRR of 0.89 (95% CI = 0.52-1.52).

CONCLUSION

Maternal AD was associated with a 29% increased incidence rate of TS in male offspring. This finding supports the hypothesis that neuroimmunological disorders may act as a component in the etiology of a subset of TS.

Pharmacokinetics and pharmacodynamics of aerosolized antibacterial agents in chronically infected cystic fibrosis patients

Bacteria adapt to growth in lungs of patients with cystic fibrosis (CF) by selection of heterogeneously resistant variants that are not detected by conventional susceptibility testing but are selected for rapidly during antibacterial treatment. Therefore, total bacterial counts and antibiotic susceptibilities are misleading indicators of infection and are not helpful as guides for therapy decisions or efficacy endpoints. High drug concentrations delivered by aerosol may maximize efficacy, as decreased drug susceptibilities of the pathogens are compensated for by high target site concentrations. However, reductions of the bacterial load in sputum and improvements in lung function were within the same ranges following aerosolized and conventional therapies. Furthermore, the use of conventional pharmacokinetic/pharmacodynamic (PK/PD) surrogates correlating pharmacokinetics in serum with clinical cure and presumed or proven eradication of the pathogen as a basis for PK/PD investigations in CF patients is irrelevant, as minimization of systemic exposure is one of the main objectives of aerosolized therapy; in addition, bacterial pathogens cannot be eradicated, and chronic infection cannot be cured. Consequently, conventional PK/PD surrogates are not applicable to CF patients. It is nonetheless obvious that systemic exposure of patients, with all its sequelae, is minimized and that the burden of oral treatment for CF patients suffering from chronic infections is reduced.

The immune response and antibacterial therapy

The host's immune defence mechanisms are indispensable factors in surviving bacterial infections. However, in many circumstances, the immune system alone is inadequate. Since the 1940s, the use of antibacterial therapy has saved millions of lives, improving the span and quality of life of individuals. Unfortunately, we are now facing an era where antibacterial agents are threatened by resistance. In addition to targeting bacteria, some antibacterial agents affect various aspects of the immune response to infection. Since many antibacterial drugs are failing in efficacy due to resistance, it has been strongly suggested that any synergy between these drugs and the immune response be exploited in the treatment of bacterial infections. This review explores the influence of antibacterial therapy on the immune response and new approaches that could exploit this interaction for the treatment of bacterial infections.

Antibiotic treatment attenuates behavioral and neurochemical changes induced by exposure of rats to group a streptococcal antigen

Post-streptococcal A (GAS) sequelae including movement and neuropsychiatric disorders have been associated with improvement in response to antibiotic therapy. Besides eradication of infection, the underlying basis of attenuation of neuropsychiatric symptoms following antibiotic treatment is not known. The aim of the present study was to test the efficacy of antibiotic treatment in a rat model of GAS-related neuropsychiatric disorders. In the model, rats were not infected but were exposed to GAS-antigen or to adjuvants only (Control rats) and treated continuously with the antibiotic ampicillin in their drinking water from the first day of GAS-antigen exposure. Two additional groups of rats (GAS and Control) did not receive ampicillin in their drinking water. Behavior of the four groups was assessed in the forced swim, marble burying and food manipulation assays. We assessed levels of D1 and D2 dopamine receptors and tyrosine hydroxylase in the prefrontal cortex and striatum, and IgG deposition in the prefrontal cortex, striatum and thalamus. Ampicillin treatment prevented emergence of the motor and some of the behavioral alterations induced by GAS-antigen exposure, reduced IgG deposition in the thalamus of GAS-exposed rats, and tended to attenuate the increase in the level of TH and D1 and D2 receptors in their striatum, without concomitantly reducing the level of sera anti-GAS antibodies. Our results reinforce the link between exposure to GAS antigen, dysfunction of central dopaminergic pathways and motor and behavioral alterations. Our data further show that some of these deleterious effects can be attenuated by antibiotic treatment, and supports the latter's possible efficacy as a prophylactic treatment in GAS-related neuropsychiatric disorders.

Prednisolone and cefapirin act synergistically in resolving experimental Escherichia coli mastitis

Mastitis in dairy cows is typically treated with intramammary antibiotics. The combination of antibiotics with corticosteroids tends to have a large market share where these products are registered. Our objective was to investigate the effect of prednisolone in combination with cefapirin on the inflammatory response of experimentally induced Escherichia coli mastitis. Six midlactating Holstein-Friesian cows were challenged in 3 quarters with E. coli and treated at 4, 12, 24, and 36 h postinfection with 300 mg of cefapirin in 1 quarter and a combination of 300 mg of cefapirin and 20mg of prednisolone in another quarter. At 24h (n=3) or 48 h (n=3) postinfection cows were euthanized for tissue sampling. Clinical scores, somatic cell count, and California mastitis test scores, as well as IL-1β, IFN-γ, IL-4, and IL-10 levels and bacterial growth in milk, were measured every 6h. Experimental inoculation caused a moderate clinical mastitis in all cows in challenged, untreated quarters. The E. coli challenge strain was recovered from all infected quarters and confirmed by PCR-based fingerprinting. Challenged, untreated control quarters showed increased concentrations of all measured cytokines together with recruitment of polymorphonuclear neutrophilic leukocytes at 24 and 48 h postchallenge. Both treatments reduced udder swelling and sensitivity with no statistically significant difference between treatment groups. Administration of cefapirin alone or in combination with prednisolone resulted in significantly lower concentrations of IFN-γ, IL-1β, and IL-10 compared with challenged, untreated quarters. Treated quarters did show IL-4 production, but concentrations were significantly decreased compared with untreated, challenged quarters. Quarters treated with the combination of cefapirin and prednisolone showed a significantly lower concentration of IL-4 compared with cefapirin-only treatment. At both 24 and 48 h postinoculation, the level of polymorphonuclear neutrophilic leukocyte recruitment was lowest in challenged quarters treated with a combination of cefapirin and prednisolone, followed by cefapirin alone. Taken together, treatment with cefapirin alone inhibited bacterial growth in milk and reduced the host inflammatory responses. Addition of prednisolone to cefapirin had a synergistic effect, resulting in a lower density of leukocytes in tissue and milk and a quicker restoration of milk quality.

The immunobiology of Tourette's disorder, pediatric autoimmune neuropsychiatric disorders associated with Streptococcus, and related disorders: a way forward

Obsessive-compulsive disorder (OCD) and related conditions including Tourette's disorder (TD) are chronic, relapsing disorders of unknown etiology associated with marked impairment and disability. Associated immune dysfunction has been reported and debated in the literature since the late 80s. The immunologic culprit receiving the most interest has been Group A Streptococcus (GAS), which began to receive attention as a potential cause of neuropsychiatric symptoms, following the investigation of the symptoms reported in Sydenham's chorea (SC) and rheumatic fever, such as motor tics, vocal tics, and both obsessive-compulsive and attention deficit/hyperactivity symptoms. Young children have been described as having a sudden onset of these neuropsychiatric symptoms temporally associated with GAS, but without supporting evidence of rheumatic fever. This presentation of OCD and tics has been termed pediatric autoimmune neuropsychiatric disorders associated with Streptococcus (PANDAS). Of note, SC, OCD, and TD often begin in early childhood and share common anatomic areas--the basal ganglia of the brain and the related cortical and thalamic sites--adding support to the possibility that these disorders might share a common immunologic and/or genetic vulnerability. Relevant manuscripts were identified through searches of the PsycINFO and MedLine databases using the following keywords: OCD, immune, PANDAS, Sydenham chorea, Tourette's disorder Group A Streptococcus. Articles were also identified through reference lists from research articles and other materials on childhood OCD, PANDAS, and TD between 1966 and December 2010. Considering the overlap of clinical and neuroanatomic findings among these disorders, this review explores evidence regarding the immunobiology as well as the relevant clinical and therapeutic aspects of TD, OCD, and PANDAS.

A beta-lactam antibiotic dampens excitotoxic inflammatory CNS damage in a mouse model of multiple sclerosis

In multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE), impairment of glial “Excitatory Amino Acid Transporters” (EAATs) together with an excess glutamate-release by invading immune cells causes excitotoxic damage of the central nervous system (CNS). In order to identify pathways to dampen excitotoxic inflammatory CNS damage, we assessed the effects of a β-lactam antibiotic, ceftriaxone, reported to enhance expression of glial EAAT2, in “Myelin Oligodendrocyte Glycoprotein” (MOG)-induced EAE. Ceftriaxone profoundly ameliorated the clinical course of murine MOG-induced EAE both under preventive and therapeutic regimens. However, ceftriaxone had impact neither on EAAT2 protein expression levels in several brain areas, nor on the radioactive glutamate uptake capacity in a mixed primary glial cell-culture and the glutamate-induced uptake currents in a mammalian cell line mediated by EAAT2. Moreover, the clinical effect of ceftriaxone was preserved in the presence of the EAAT2-specific transport inhibitor, dihydrokainate, while dihydrokainate alone caused an aggravated EAE course. This demonstrates the need for sufficient glial glutamate uptake upon an excitotoxic autoimmune inflammatory challenge of the CNS and a molecular target of ceftriaxone other than the glutamate transporter. Ceftriaxone treatment indirectly hampered T cell proliferation and proinflammatory INFγ and IL17 secretion through modulation of myelin-antigen presentation by antigen-presenting cells (APCs) e.g. dendritic cells (DCs) and reduced T cell migration into the CNS in vivo. Taken together, we demonstrate, that a β-lactam antibiotic attenuates disease course and severity in a model of autoimmune CNS inflammation. The mechanisms are reduction of T cell activation by modulation of cellular antigen-presentation and impairment of antigen-specific T cell migration into the CNS rather than or modulation of central glutamate homeostasis.

Effect of feline interferon-omega on the survival time and quality of life of cats with feline infectious peritonitis

BACKGROUND

There is no therapy with proven efficacy to treat cats with feline infectious peritonitis (FIP).

HYPOTHESIS

Feline interferon-omega (FeIFN-omega) prolongs survival time and increases quality of life in cats with FIP.

ANIMALS

Thirty-seven privately owned cats were subjects of this study.

METHODS

The study was performed as a placebo-controlled double-blind trial. Feline infectious peritonitis was confirmed by histology or immunostaining of feline coronavirus (FCoV) antigen in effusion or tissue macrophages or both. The cats were randomly selected for treatment with either FeIFN-omega or a placebo. All cats received adjunctive treatment with glucocorticoids and antibiotics and passive immunization with Feliserin.

RESULTS

There was no statistically significant difference in the survival time of cats treated with FeIFN-omega versus placebo or in any other variable evaluated (with the exception of the lymphocyte count). The cats survived between 3 and 200 days (median, 9 days). There was only 1 long-term survivor (> 3 months), and the cat was in the FeIFN-omega group.

CONCLUSION AND CLINICAL RELEVANCE

No effect of FeIFN-omega on survival time or quality of life could be demonstrated in this study.

Effect of feline interferon-omega on the survival time and quality of life of cats with feline infectious peritonitis

Background: There is no therapy with proven efficacy to treat cats with feline infectious peritonitis (FIP).

Hypothesis: Feline interferon‐omega (FeIFN‐ω) prolongs survival time and increases quality of life in cats with FIP.

Animals: Thirty‐seven privately owned cats were subjects of this study.

Methods: The study was performed as a placebo‐controlled double‐blind trial. Feline infectious peritonitis was confirmed by histology or immunostaining of feline coronavirus (FCoV) antigen in effusion or tissue macrophages or both. The cats were randomly selected for treatment with either FeIFN‐to or a placebo. All cats received adjunctive treatment with glucocorticoids and antibiotics and passive immunization with Feliserin.

Results: There was no statistically significant difference in the survival time of cats treated with FeIFN‐ω versus placebo or in any other variable evaluated (with the exception of the lymphocyte count). The cats survived between 3 and 200 days (median, 9 days). There was only 1 long‐term survivor (>3 months), and the cat was in the FeIFN‐ω group.

Conclusion and Clinical Relevance: No effect of FeIFN‐ω on survival time or quality of life could be demonstrated in this study.