The Use of Bacterial Lysate for the Prevention of Wheezing Episodes in Preschool Children: A Cost-Utility Analysis

BACKGROUND

Although increasing recent evidence has shown the efficacy of bacterial lysate therapy for the prevention of wheezing episodes and asthma exacerbations in pediatric patients, evidence of its cost-effectiveness in preschool patients is scarce.

OBJECTIVES

To evaluate the cost-utility of bacterial lysate therapy as an add-on to standard care of preschool children with recurrent wheezing.

METHODS

To achieve the objectives of the study, we used a Markov simulation model with 3 mutually exclusive nonabsorbent states (regular Markov chain). Effectiveness parameters were obtained from a recent systematic review of the literature with meta-analyses (5 randomized controlled trials, 433 children). Cost data were obtained from hospital bills and from the national manual of drug prices in Colombia. The study was carried out from the perspective of the national health care system in Colombia. The main outcome of the model was quality-adjusted life-years. To assess the robustness of the model's results, we performed deterministic and probabilistic sensitivity analysis.

RESULTS

Compared with standard care, bacterial lysate add-on therapy to standard care was associated with lower overall treatment costs (US $694.03 vs $830.71 average cost per patient) and the greatest gain in QALYs (0.9211 vs 0.9154 QALYs on average per patient), thus showing dominance.

CONCLUSIONS

In Colombia, compared with standard care, bacterial lysate add-on therapy to standard care for treating preschool children with recurrent wheezing is a dominant strategy because it showed a greater gain in QALYs at lower total treatment costs.

Airway administration of OM-85, a bacterial lysate, blocks experimental asthma by targeting dendritic cells and the epithelium/IL-33/ILC2 axis

BACKGROUND

Microbial interventions against allergic asthma have robust epidemiologic underpinnings and the potential to recalibrate disease-inducing immune responses. Oral administration of OM-85, a standardized lysate of human airways bacteria, is widely used empirically to prevent respiratory infections and a clinical trial is testing its ability to prevent asthma in high-risk children. We previously showed that intranasal administration of microbial products from farm environments abrogates experimental allergic asthma.

OBJECTIVES

We sought to investigate whether direct administration of OM-85 to the airway compartment protects against experimental allergic asthma; and to identify protective cellular and molecular mechanisms activated through this natural route.

METHODS

Different strains of mice sensitized and challenged with ovalbumin or Alternaria received OM-85 intranasally, and cardinal cellular and molecular asthma phenotypes were measured. Airway transfer experiments assessed whether OM-85-treated dendritic cells protect allergen-sensitized, OM-85-naive mice against asthma.

RESULTS

Airway OM-85 administration suppressed allergic asthma in all models acting on multiple innate and adaptive immune targets: the airway epithelium/IL-33/ILC2 axis, lung allergen-induced type 2 responses, and dendritic cells whose Myd88/Trif-dependent tolerogenic reprogramming was sufficient to transfer OM-85-induced asthma protection.

CONCLUSIONS

We provide the first demonstration that administering a standardized bacterial lysate to the airway compartment protects from experimental allergic asthma by engaging multiple immune pathways. Because protection required a cumulative dose 27- to 46-fold lower than the one reportedly active through the oral route, the efficacy of intranasal OM-85 administration may reflect its direct access to the airway mucosal networks controlling the initiation and development of allergic asthma.

The OM-85 bacterial lysate inhibits SARS-CoV-2 infection of epithelial cells by downregulating SARS-CoV-2 receptor expression

Background

Treatments for coronavirus disease 2019, which is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), are urgently needed but remain limited. SARS-CoV-2 infects cells through interactions of its spike (S) protein with angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2) on host cells. Multiple cells and organs are targeted, particularly airway epithelial cells. OM-85, a standardized lysate of human airway bacteria with strong immunomodulating properties and an impeccable safety profile, is widely used to prevent recurrent respiratory infections. We found that airway OM-85 administration inhibits Ace2 and Tmprss2 transcription in the mouse lung, suggesting that OM-85 might hinder SARS-CoV-2/host cell interactions.

Objectives

We sought to investigate whether and how OM-85 treatment protects nonhuman primate and human epithelial cells against SARS-CoV-2.

Methods

ACE2 and TMPRSS2 mRNA and protein expression, cell binding of SARS-CoV-2 S1 protein, cell entry of SARS-CoV-2 S protein–pseudotyped lentiviral particles, and SARS-CoV-2 cell infection were measured in kidney, lung, and intestinal epithelial cell lines, primary human bronchial epithelial cells, and ACE2-transfected HEK293T cells treated with OM-85 in vitro.

Results

OM-85 significantly downregulated ACE2 and TMPRSS2 transcription and surface ACE2 protein expression in epithelial cell lines and primary bronchial epithelial cells. OM-85 also strongly inhibited SARS-CoV-2 S1 protein binding to, SARS-CoV-2 S protein–pseudotyped lentivirus entry into, and SARS-CoV-2 infection of epithelial cells. These effects of OM-85 appeared to depend on SARS-CoV-2 receptor downregulation.

Conclusions

OM-85 inhibits SARS-CoV-2 epithelial cell infection in vitro by downregulating SARS-CoV-2 receptor expression. Further studies are warranted to assess whether OM-85 may prevent and/or reduce the severity of coronavirus disease 2019.

Polyvalent Mechanical Bacterial Lysate Administration Improves the Clinical Course of Grass Pollen-Induced Allergic Rhinitis in Children: A Randomized Controlled Trial

BACKGROUND

Recent studies highlight the immunoregulatory potential of bacterial lysates, indicating their potential use in the prevention and treatment of allergic diseases.

OBJECTIVE

To investigate the clinical efficacy of polyvalent mechanical bacterial lysates (PMBLs) in children with grass pollen-induced allergic rhinitis.

METHODS

Seventy children with seasonal allergic rhinitis were enrolled to this study and were randomly assigned to the PMBL and placebo groups. Severity of seasonal allergic rhinitis symptoms was assessed by the total nasal symptom score, total ocular symptom score, and visual analogue scale. During 3 visits, peak nasal inspiratory flow was measured, and nasal smears for the presence of eosinophils and nasal lavage fluids for the presence of allergen-specific IgE against timothy grass pollen allergens were sampled.

RESULTS

A statistically significant decrease in total nasal symptom score (P = .001), total ocular symptom score (P = .04), and visual analogue scale score for nasal and eye symptoms (P < .001 and P < .001, respectively) and an increase in peak nasal inspiratory flow (P = .04) were observed in the PMBL group versus the placebo group. During the grass pollen season, an increase and then a decrease in the number of eosinophils in nasal smears was observed in both groups; however, the number of eosinophils was significantly lower in the PMBL group versus the placebo group. No significant changes in allergen-specific IgE concentrations were observed in the PMBL group, whereas in the placebo group a statistically significant increase in allergen-specific IgE concentration was observed.

CONCLUSIONS

Sublingual administration of PMBLs during the grass pollen season offers significant efficacy in alleviating seasonal allergic rhinitis symptoms in children sensitized to grass pollen allergens. PMBLs probably affect mucosal immunity, weakening the response of T_H2 cells.

Viral infections and wheezing-asthma inception in childhood: is there a role for immunomodulation by oral bacterial lysates?

Severe and recurrent infections of the respiratory tract in early childhood constitute major risk factors for the development of bronchial hyper-responsiveness and obstructive respiratory diseases in later life. In the first years of life, the vast majority of respiratory tract infections (RTI) leading to wheezing and asthma are of a viral origin and severity and recurrence are the consequence of a greater exposure to infectious agents in a period when the immune system is still relatively immature. Therefore, boosting the efficiency of the host immune response against viral infections seems to be a rational preventative approach. In the last decades it has been demonstrated that living in farm environments, i.e. early-life exposure to microbes, may reduce the risk of allergic and infectious disorders, increasing the immune response efficacy. These findings have suggested that treatment with bacterial lysates could promote a nonspecific immunomodulation useful in the prevention of recurrent RTIs and of wheezing inception and persistence. Experimental and clinical studies showing the reduction of RTI frequency and severity in childhood and elucidating the involved mechanisms can support this hypothesis.

Establishing a high microbial load maternal-offspring asthma model in adult mice

BACKGROUND

Although it is widely accepted that the "hygiene hypothesis" explains the increased incidence of asthma, the lack of suitable animal models hinders further in-depth studies of the underlying molecular immune mechanisms. Therefore, we aimed to develop a robust mouse asthma model to investigate the role of bacteria in preventing asthma.

METHODS

BALB/c female mice were fed a mixture of eight common bacterial lysates (BL; Broncho-Vaxom®) and a commercial probiotic (Bifidobacterium tetravaccine tablets) at different concentrations before and during pregnancy to simulate different microbial load levels. Faeces from the mother mice were subjected to bacterial 16S rRNA sequencing to quantify the maternal microbial load. TLR2/4 expression and the proportion of regulatory T cells (Tregs) in the intestinal tract of female mice were determined, and the safety of the microbial load was evaluated. An asthma model was established in the offspring mice after weaning, and the extent of pulmonary pathological changes and Treg proportion were evaluated.

RESULTS

A BL concentration of 1 mg/kg enriched the intestinal flora, increased the proportion of Tregs, and increased the expression of TLR2/4 in the maternal mice. The proportion of peripheral blood Tregs was increased, whereas the risk of asthma decreased only in the offspring from mothers with a high microbial load relative to control mice.

CONCLUSION

This study established a safe and stable high microbial load maternal-offspring mouse asthma model, laying the foundation for a study on the molecular mechanism underlying the protective effects of a high microbial load against asthma.

A randomized, placebo-controlled, double-blinded, single-centre, phase IV trial to assess the efficacy and safety of OM-85 in children suffering from recurrent respiratory tract infections

BACKGROUND

Over many years, OM-85, a lysate of 21 common bacterial respiratory pathogens, has been demonstrated to prevent respiratory recurrences in children. However, further studies are needed to explore the true importance of OM-85 in the prevention of respiratory tract infections (RTIs) in children. This study was planned to further contribute to the evaluation of the role played by OM-85 in prevention of recurrent RTIs in children.

METHODS

This study was a randomized (3:3:1), placebo-controlled, double-blind, single-centre, phase IV trial carried out in Italy to assess the efficacy of OM-85 (Broncho-Vaxom®; Vifor Pharma; Meyrin 2/Geneva, Switzerland) in reducing the number of new RTI episodes in 288 children aged 1 to 6 years with a history of recurrent RTIs and to compare the efficacy of the standard 3-month regimen with that of administration of OM-85 for 6 months during a 6-month study period.

RESULTS

The number of RTIs and of children who experienced at least one RTI were significantly lower among patients receiving OM-85 for 3 months than among those given placebo (33% vs 65.1%, p < 0.0001). Differences were statistically significant for upper RTIs (i.e., common cold/viral pharyngitis and acute otitis media; p < 0.0001 and p = 0.006, respectively). Days of absence from day-care for children and working days lost by parents were significantly lower in the group with children treated with OM-85 for 3 months than in the placebo group (p = 0.007 and p = 0.004, respectively). No difference was seen between children who received OM-85 for 3 and those who received OM-85 for 6 months. The prevalence of atopy as well as the history of recurrent wheezing and age of the study child did not influence the results. Benefit was maximally evident among children with a history of frequent recurrences. OM-85 was well tolerated and safe, even in children who received an influenza vaccination.

CONCLUSIONS

The use of OM-85 for 3 months in 3 series of 10 consecutive days each time reduces the risk of recurrent RTIs in children, with a favourable safety profile. The greater effect observed in children prone to several respiratory episodes than in non-prone children seems to indicate that this lysate should be administered especially to children with a proven high susceptibility to RTIs.

Label-free electrical sensing of bacteria in eye wash samples: A step towards point-of-care detection of pathogens in patients with infectious keratitis

The diagnosis of keratitis is based on visual exam, tissue cytology, and standard microbial culturing to determine the type of the infectious pathogen. To prescribe appropriate therapy, it is important to distinguish between bacterial, fungal, and viral keratitis, as the treatments are quite different. Diagnosis of the causative organism has a substantial prognostic importance. Further, timely knowledge of the nature of the pathogen is also critical to adapt therapy in patients unresponsive to empiric treatment options, which occurs in 10% of all cases. Currently, the identification of the nature of the pathogen that causes keratitis is achieved via microbial culture screening, which is laboratory-based, expensive, and time-consuming. The most frequent pathogens that cause the corneal ulcers are P. aeruginosa and S. aureus. Here, we report a microchip for rapid (<1h) detection of P. aeruginosa (6294), S. aureus(LAC), through on-chip electrical sensing of bacterial lysate. We evaluated the microchip with spiked samples of PBS with bacteria concentration between 10¹ to 10⁸ CFU/mL. The least diluted bacteria concentration in bacteria-spiked samples with statistically significant impedance change was 10 CFU/mL. We further validated our assay by comparing our microchip results with the standard culture-based methods using eye washes obtained from 13 infected mice.

Aflatoxin B1 degradation by liquid cultures and lysates of three bacterial strains

Aflatoxin contamination remains a daunting issue to address in food safety. In spite of the efforts geared towards prevention and elimination of this toxin, it still persists in agricultural commodities. This has necessitated the search for other measures such as microbial degradation to combat this hazard. In this study, we investigated the biodegradation of aflatoxin B1 (AFB1), using lysates of three bacterial strains (Pseudomonas anguilliseptica VGF1, Pseudomonas fluorescens and Staphylococcus sp. VGF2) isolated from a gold mine aquifer. The bacterial cells were intermittently lysed in the presence and absence of protease inhibitors to obtain protease free lysates, subsequently incubated with AFB1 for 3, 6, 12, 24, and 48h to investigate whether any possible AFB1 degradation occurred using high performance liquid chromatography (HPLC) for detection. Results obtained revealed that after 6h of incubation, protease inhibited lysates of Staphylococcus sp. VGF2 demonstrated the highest degradation capacity of 100%, whereas P. anguilliseptica VGF1 and P. fluorescens lysates degraded AFB1 by 66.5 and 63%, respectively. After further incubation to 12h, no residual AFB1 was detected for all the lysates. Lower degrading ability was however observed for liquid cultures and uninhibited lysates. Data on cytotoxicity studies against human lymphocytes showed that the degraded products were less toxic than the parent AFB1. From this study, it can thus be deduced that the mechanism of degradation by these bacterial lysates is enzymatic. This study shows the efficacy of crude bacterial lysates for detoxifying AFB1 indicating potential for application in the food and feed industry.

Clinical and Immunological Benefits of OM-85 Bacterial Lysate in Patients with Allergic Rhinitis, Asthma, and COPD and Recurrent Respiratory Infections

Purpose

The aim of this study was to evaluate the efficacy of OM-85 in reducing the incidence of respiratory tract infections (RTIs) in patients with allergic rhinitis, asthma, or chronic obstructive pulmonary disease (COPD), and its effect on immunological parameters, namely serum and secretory IgA levels.

Methods

This was an open-label, prospective, sequential study which included 84 consecutive patients aged 16–65 years, who presented with recurrent (three or more) respiratory infections during the year prior to study entry. In the first year of the study, patients received standard optimized care (SOC), according to their underlying disease condition (asthma, allergic rhinitis, or COPD). In the following year, patients received treatment with OM-85 oral bacterial lysate (one 7 mg capsule daily for ten consecutive days per month, for 3 months), with a 6-month follow-up. Medical history, clinical symptoms, serum, and secretory IgA levels, and the number of infections and exacerbations were evaluated before and after treatment.

Results

There was a decrease in the total number of RTIs before the OM-85 treatment period (SOC only) compared to the year before the study start [69/266 (corresponding to a 74 % reduction)] and an additional decrease [38/69 (corresponding to a 45 % reduction)] after OM-85 treatment; p < 0.05. There was also a significant reduction in the total number of exacerbations related to the patients’ underlying medical conditions, which decreased from 55 to 35 during OM-85 (+SOC) treatment, corresponding to a reduction of 36 %. In addition, an increase in serum and secretory IgA levels which coincided with the administration of OM-85 was observed.

Conclusions

Our results showed the clinical benefits of OM-85 in reducing RTIs and exacerbations of the underlying medical condition, in patients with allergic rhinitis, asthma, or COPD.

Impact of a mixed bacterial lysate (OM-85 BV) on the immunogenicity, safety and tolerability of inactivated influenza vaccine in children with recurrent respiratory tract infection

It is known that the immunogenicity and efficacy of conventional inactivated influenza vaccines (IIVs) are not completely satisfactory in children. The aim of this prospective, randomised, single-blind study was to compare the immune response to, and the effectiveness and safety of, an IIV (Fluarix, GlaxoSmithKline Biologicals, Rixensart, Belgium) administered to 68 children aged 36-59 months affected by recurrent respiratory tract infections (RRTIs) who were vaccinated with (n=33) or without (n=35) the mixed bacterial lysate OM-85 BV (Broncho-vaxom, Vifor Pharma, Geneva, Switzerland). OM-85 BV had no effect on seroconversion or seroprotection rates, geometric mean titres, or dendritic cells, which were not significantly different between the two groups. Moreover, OM-85 BV did not significantly increase the pool of the memory B cells that produce IgG and IgM antibodies against the influenza antigens. However, respiratory morbidity was significantly lower in the children treated with OM-85 BV (p<0.05), thus confirming its positive effect on the incidence of RRTIs. There was no difference in the incidence of adverse events between the two groups. These findings show that the immune response of children to influenza vaccine is not significantly influenced by the administration of OM-85 BV. However, the use of OM-85 before and at the same time as IIV seems to reduce respiratory morbidity, and seems to be safe and well tolerated.