Probiotics have shown excellent application prospects in preventing and treating many diseases. However, their sensitivity to the harsh environment in vivo always leads to a massive loss of viability and insufficient therapeutic effect. Fortunately, modified probiotics have emerged and provide multiple possibilities for their use in various diseases. Modification not only endows probiotics with extra capacity to resist severe environments but also gives them exogenous characteristics, such as prolonged retention time and improved therapeutic effects. Modified probiotics could combine with other therapies, which has opened up new avenues to enhance the efficacy of probiotic-based therapy. In this review, we have summarized the current physicochemical and biological modification strategies of probiotics. In addition, the progress of research on probiotic-based combination therapy has also been extensively reviewed, which contributes to the enhanced delivery of probiotics or other active constituents and provides new ideas for disease treatment, bioimaging, and diagnosis.

Objective To analyze the influence of meteorological factors on the number of influenza-like illness (ILI) cases in Urumqi, Xinjiang, and establish an ARIMAX (autoregressive integrated moving average model-X) model to make short-term prediction of the number of ILI cases, so as to provide theoretical basis for the prevention and control of influenza in Urumqi. Methods The number of ILI cases in Urumqi from January 2015 to September 2017 and meteorological data of the same period were used to establish ARIMAX model and predict the number of ILI cases in Urumqi from October 2017 to March 2018. Results The ARIMA (0,1,1) (1,1,0)₁₂ model was established from January 2015 to September 2017, AIC = 200.09. According to residual correlation function (CCF), there was a positive correlation between monthly average relative humidity and ILI cases, and a negative correlation between monthly sunshine hours and ILI cases. The average monthly relative humidity and monthly sunshine hours were taken as influencing variables to establish the ARIMAX model. Among them, the ARIMAX model incorporating the lagging order of 0 of monthly sunshine hours had the smallest AIC (AIC=197.63), and all parameters of the model were statistically significant. Compared with the univariate time series ARIMA model, the mean absolute percentage error (MAPE) of fitting was reduced by 1.3687%, the predicted MAPE was reduced by 5.25%, and the prediction accuracy was improved. Conclusion The ARIMAX model with meteorological factors established in this study can better predict the incidence trend of ILI cases in a short time, providing evidence for influenza surveillance and prevention and control.

Staphylococcus aureus (S. aureus) is an important human pathogen which can cause a chronic condition with a high relapse rate despite the aggressive antimicrobial treatment. Recent studies showed that intracellular pattern recognition receptors (including NOD) in response to bacteria or bacterial products play a proinflammatory role by activating nuclear transcription factor-κB (NF-κB). But how NOD2 mediates the proinflammatory response to S. aureus in mast cells (MCs) is unclear. So, in this study, we attempted to examine the role of NOD2 in inflammatory responses of MCs to S. aureus. P815 cells (a mouse mast cell line) were cultured. Real-time PCR was used to detect the NOD2 mRNA expression in P815 cells during S. aureus infection. The siRNA against NOD2 gene was synthesized and transfected into S. aureus-infected P815 cells. By using the methods of ELISA and flow cytometry, the effects of NOD2 gene silencing on cell phagocytosis, cytokine secretion, NF-κB activation and cell apoptosis of the S. aureus-infected P815 cells were examined. It was found that S. aureus infection could increase the expression of NOD2 mRNA in P815 cells. NOD2 gene interference in P815 cells reduced the number of S. aureus engulfed by P815 cells, the level of cytokines and the activation of NF-κB. In addition, S. aureus could induce the apoptosis of P815 cells, but NOD2 gene silencing did not affect the cell apoptosis rate. Our data suggested that NOD2 plays a key role in pathogen recognition, signal transduction, and NF-κB activation in the inflammatory responses of MCs infected by S. aureus.

In order to investigate the role of the MexA-MexB-OprM efflux pump system in the pathogenesis of Pseudomonas aeruginosa (PA)-induced pulmonary infection, pulmonary infection models were established by intratracheal injection of K767 (wild type), nalB (MexA-MexB-OprM up-regulated mutant), and ΔmexB (knockout) strains, separately. All mice were treated with Meropenem (intraper Δ itoneal injection, 100 mg/kg body weight, twice every day), and strain-related pathology, bacteria count, cytokine level, myeloperoxidase (MPO, indicator of neutrophil recruitment) activity, and macrophage inflammatory protein-2 (MIP-2) expression were evaluated at early (3rd day post-infection) and late (7th and 14th day post-infection) stages of infection. E-test showed that ΔmexB was more significantly Δ sensitive to panipenan (ETP), meropenem (MP) and imipenem (IP) than K767 and nalB strains. There was no significant difference in sensitivity to cefepime (TM) among the three stains. In contrast to the K767 and nalB groups, the ΔmexB group showed decreased bacteria burden over time and less exte Δ nsive pathological change. Additionally, MPO activity and levels of inflammatory cytokines (IL-1b, IL-12, and TNF-α) were increased at the early stage (day 3) and decreased at the later stage (day 14). Serum MIP-2 expression level was steadily increased in all three groups from early to late stages, but significantly higher in ΔmexB group than in K767 and nalB groups ( Δ P<0.05). In conclusion, the MexA-MexB-OprM efflux pump system might play an important role in PA-induced chronic pulmonary infection. High expression of the MexA-MexB-OprM efflux pump could increase antibacterial resistance and promote infection.

In order to investigate the role of the MexA-MexB-OprM efflux pump system in the pathogenesis of Pseudomonas aeruginosa (PA)-induced pulmonary infection, pulmonary infection models were established by intratracheal injection of K767 (wild type), nalB (MexA-MexB-OprM up-regulated mutant), and ΔmexB (knockout) strains, separately. All mice were treated with Meropenem (intraper Δ itoneal injection, 100 mg/kg body weight, twice every day), and strain-related pathology, bacteria count, cytokine level, myeloperoxidase (MPO, indicator of neutrophil recruitment) activity, and macrophage inflammatory protein-2 (MIP-2) expression were evaluated at early (3rd day post-infection) and late (7th and 14th day post-infection) stages of infection. E-test showed that ΔmexB was more significantly Δ sensitive to panipenan (ETP), meropenem (MP) and imipenem (IP) than K767 and nalB strains. There was no significant difference in sensitivity to cefepime (TM) among the three stains. In contrast to the K767 and nalB groups, the ΔmexB group showed decreased bacteria burden over time and less exte Δ nsive pathological change. Additionally, MPO activity and levels of inflammatory cytokines (IL-1b, IL-12, and TNF-α) were increased at the early stage (day 3) and decreased at the later stage (day 14). Serum MIP-2 expression level was steadily increased in all three groups from early to late stages, but significantly higher in ΔmexB group than in K767 and nalB groups ( Δ P<0.05). In conclusion, the MexA-MexB-OprM efflux pump system might play an important role in PA-induced chronic pulmonary infection. High expression of the MexA-MexB-OprM efflux pump could increase antibacterial resistance and promote infection.
Animals ; Bacterial Outer Membrane Proteins ; metabolism ; Lung ; microbiology ; Membrane Transport Proteins ; metabolism ; Mice ; Mice, Inbred BALB C ; Pseudomonas Infections ; metabolism ; microbiology ; Pseudomonas aeruginosa ; metabolism

Staphylococcus aureus (S. aureus) is an important human pathogen which can cause a chronic condition with a high relapse rate despite the aggressive antimicrobial treatment. Recent studies showed that intracellular pattern recognition receptors (including NOD) in response to bacteria or bacterial products play a proinflammatory role by activating nuclear transcription factor-κB (NF-κB). But how NOD2 mediates the proinflammatory response to S. aureus in mast cells (MCs) is unclear. So, in this study, we attempted to examine the role of NOD2 in inflammatory responses of MCs to S. aureus. P815 cells (a mouse mast cell line) were cultured. Real-time PCR was used to detect the NOD2 mRNA expression in P815 cells during S. aureus infection. The siRNA against NOD2 gene was synthesized and transfected into S. aureus-infected P815 cells. By using the methods of ELISA and flow cytometry, the effects of NOD2 gene silencing on cell phagocytosis, cytokine secretion, NF-κB activation and cell apoptosis of the S. aureus-infected P815 cells were examined. It was found that S. aureus infection could increase the expression of NOD2 mRNA in P815 cells. NOD2 gene interference in P815 cells reduced the number of S. aureus engulfed by P815 cells, the level of cytokines and the activation of NF-κB. In addition, S. aureus could induce the apoptosis of P815 cells, but NOD2 gene silencing did not affect the cell apoptosis rate. Our data suggested that NOD2 plays a key role in pathogen recognition, signal transduction, and NF-κB activation in the inflammatory responses of MCs infected by S. aureus.
Animals ; Cell Line ; Cytokines ; immunology ; Inflammation Mediators ; immunology ; Mast Cells ; immunology ; microbiology ; Mice ; NF-kappa B ; immunology ; Nod2 Signaling Adaptor Protein ; immunology ; Staphylococcus aureus ; physiology

Objective To investigate the efficacy of small interfering RNA against Pseudomonos aeruginosa expressing MexA-MexB-OprM multidrug efflux pump in vivo.Methods Two short hairpin (sh)RNA expression vectors targeting the MexB gene,and negative controls,were designed,synthesized,and electrotransformed into the P.aeruginosa strain PAO1.The in vivo therapeutic efficacy of the MexB small interfering (si)RNAs was determined by infecting a murine model of chronic P.aeruginosa lung infection (1 × 107 CFU/ml).The mice were killed on day 3,5 and 7 after infection with the Pseudomonas aeruginosa strains.Results In the murine infection model,treatment with MexB-siRNAs led to significantly reduced bacteria burden of the bellows by day 5 and 7 post-infection,and reduced the P.aeruginosa-induced pathological changes.In addition,MexB-siRNA2 treatment enhanced neutrophil recruitment and production of inflammatory cytokines (IL-1β,IL-12) in the early infection stage (day 3) (P＜0.05),both of which decreased by day 7.Conclusion MexB-siRNA could inhibit both mRNA expression and the activity of P.aeruginosa in vitro.siRNA was effective in reducing the bacterial load in a murine model of chronic lung infection.Targeting of MexB with siRNA appears to be a novel strategy for treating P.aeruginosa infections.

Objective To investigate the effect and mechanism of siHybrids technique on inhibiring the efflux pump gene mexB of Pseudomonas aeruginosa PAO1 in vitro. MethodsTargeting the efflux pump gene mexB of Pseudomonas aeruginosa PAO1 ,we designed and synthesized three siHybrids molecule and one negative scamble siHybrids molecule. Pseudomonas aeruginosa PAO1 were intervened by the siHybrids molecules in 50 nmol/L, respectively. And the experiments were made of control groups[blank and scamble (sc) -001]and intervened groups[siHybrids( si ) -001, siHybrids( si ) -002 and siHybrids(si) -003]of Pseudomonas aeruginosa PAO1. The targeting efflux pump gene mexB mRNA expressions of Pseudomonas aeruginosa PAO1, including all groups, were measured by real-time PCR in 12 h and 24 h after interference in vitro. Further, the minimal inhibitory concentration (MIC) of chlormycetinCP, erythrocin( EM ), levofloxacin ( L-OFLX), ceftazidime ( CAZ), meropenem (MER) to those groups were detected by using Mueller-Hinton broth dilution before and after interference. ResultsThe relative mexB mRNA amounts of Pseudomonas aeruginosa PAO1 intervened by different siHybrids were not much more different from each other after 12 h,but the expression of mexB mRNA of the intervened group ( si-001 ,si-002 ,si-003 ) was much lower than control groups after interference for 24 h. The relative mexB mRNA amounts, comparing 12 h with 24 h, we would find the blank control and negative control submit escalating trend. And the intervened control ,three different siHybrids were all with a downward tendency. However, in presence of 50 nmol/L siHybrids, the minimal inhibitory concentration(MIC) of CP, EM, L-OFLX, CAZ, MER to those controls were not much more different before and after interference. Conclusion On level of the mRNA expressions, siHybrids could inhibit the efflux pump gene mexB of Pseudomonas aeruginosa PAO1 in vitro, and within 24 h would be able to function effectively. Further, the effect was time-dependent.

Objective To identify the efficacy small interfering RNA against Pseudomonas aeruginosa expressing MexA-MexB-OprM efflux pumps.Methods Four siRNA ( siRNA1,siRNA2,siRNA3 and siRNA4) against mexB gene were designed and prepared by electricity transference in vitro.MICs of antibiotic combined with efflux pump inhibitors against multiple resistant strain PAO1 and PAO3 were determined by E-test method.The mRNA expression levels of efflux pump gene (mexB) were quantified by real time fluorescent quantitative PCR.Results siRNA expression vectors were constructed success by enzyme cut method.48 after PAO1 and multiple drug resistant PAO3 transfected with siRNA4,the sensibilities to antibiotic were enhanced.48 after PAO1 and multiple drug resistant PAO3 transfected with siRNAl,siRNA2 and siRNA3,the sensibilities to antibiotic didn't change obviously.48 after PAO1 and multiple drug resistant PAO3 ttransfected with siRNA4,the expression level of mexB was decreased obviously (P ＜ 0.05 ).48 after PAO1 and multiple drug resistant PAO3 transfected with siRNA1,siRNA2 and siRNA3,the expression level of mexB didn't change obviously.Conclusion siRNA against Pseudomonas aeruginosa expressing MexA-MexB-OprM efflux pumps enhanced the sensibility to antibiotic and inhibited the expression of mexB gene.Our results demonstrate the using RNAi may be potential targets for novel therapies directed against treatment of antibiotic-resistant infections.

ObjectiveTo investigate the alteration of MexB protein expression by plasmid containing siRNA template strand was transformed into Pseudomonas aeruginosa.Methods siRNA molecules specifically against mexB were designed and ligated into pGPU6/GFP/Neo vector to construct the recombinant plasmid pGPU6/GFP/Neo-siRNA.MexB gene was cloned into expression vector pET22b+ to construct plasmid pET22b+/mexB,the recombinant expression plasmid was transformed into E.coli BL21 (DE3)plysS and protein MexB was induced to express,then purified protein MexB was used to prepare specific antibodies in rabbits.The plasmids with siRNA molecules specifically against mexB were transformed into wild type strain,clinical multiresistant strain and mexB overexpression strain of Pseudomonas aeruginosa by electroporation respectively,and the changes of the expression of MexB were detected in 8,12,24 h respectively by Western blot.ResultspGPU6/GFP/Neo-siRNA was constructed successfully.Protein MexB was expressed successfully and the rabbit polyclonal antibodies against MexB was prepared well.The gene silence of mexB by siRNA molecules was effective in the three strains of Pseudomonas aeruginosa,but it depended on the silencing time.ConclusionThe expression of MexB was reduced in 8 h and 12 h,but in 24 h,the expression was unchanged.